diff options
| author | prashantsinalkar | 2017-10-10 12:27:19 +0530 |
|---|---|---|
| committer | prashantsinalkar | 2017-10-10 12:27:19 +0530 |
| commit | 7f60ea012dd2524dae921a2a35adbf7ef21f2bb6 (patch) | |
| tree | dbb9e3ddb5fc829e7c5c7e6be99b2c4ba356132c /965 | |
| parent | b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b (diff) | |
| download | Scilab-TBC-Uploads-7f60ea012dd2524dae921a2a35adbf7ef21f2bb6.tar.gz Scilab-TBC-Uploads-7f60ea012dd2524dae921a2a35adbf7ef21f2bb6.tar.bz2 Scilab-TBC-Uploads-7f60ea012dd2524dae921a2a35adbf7ef21f2bb6.zip | |
initial commit / add all books
Diffstat (limited to '965')
224 files changed, 4899 insertions, 0 deletions
diff --git a/965/CH11/EX11.1/1.sci b/965/CH11/EX11.1/1.sci new file mode 100644 index 000000000..b6ad157f9 --- /dev/null +++ b/965/CH11/EX11.1/1.sci @@ -0,0 +1,12 @@ +clc;
+clear all;
+disp("rate of energy emmission")
+A=0.12;//m^2
+T=527+273;// K
+sigma=5.67*10^(-8);
+Eb=sigma*A*T^4;//W
+disp("W",Eb,"The total rate of energy emmision, Eb =")
+Ibn=sigma*(T/100)^4/10^(-8);// W/m^2 sr
+disp("W/m^2 .sr",Ibn,"Intensity of normal radiation , Ibn =")
+lmax=2898/T;//mu.m
+disp("mu m",lmax, "Wavelength of maximum monochromatic emmissive power = ")
diff --git a/965/CH11/EX11.2/2.sci b/965/CH11/EX11.2/2.sci new file mode 100644 index 000000000..8d1aac88b --- /dev/null +++ b/965/CH11/EX11.2/2.sci @@ -0,0 +1,10 @@ +clc;
+clear all;
+disp("surface temperature of sun")
+lmax=0.49;//mu m
+T=2898/lmax;//mu.m
+disp("K",T, "surface temperature of sun = ")
+
+sigma=5.67*10^(-8);
+Eb=sigma*T^4;//W/m^2
+disp("W/m^2",Eb,"The total rate of energy emmision, Eb =")
diff --git a/965/CH11/EX11.3/3.sci b/965/CH11/EX11.3/3.sci new file mode 100644 index 000000000..8b1ef396d --- /dev/null +++ b/965/CH11/EX11.3/3.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("monochromatic emmisive power")
+T=2500+273;//K
+l=1.2*10^(-6);// m
+e=0.9;
+sigma=5.67*10^(-8);
+C1=3.742*10^(-15);// W m^4/m2
+C2=1.4388*10^(-2);// mK
+Elb=(C1*l^(-5))/(exp(C2/(l*T))-1);// W/m^2
+disp("W/m^2",Elb,"monochromatic emmisive power at l= 1.2 mu m = ")
+lmax=2898/T;
+disp("mu m",lmax,"wavelength at which the emission is maximum is")
+Elbmax = (1.285*10^(-5))*T^5;// W/m^2
+disp("W/m^2 per meter length",Elbmax,"Maximum emissive power =")
+Eb=sigma*T^4;//W/m^2
+disp("W/m^2",Eb,"total emissive power =")
+Eeb= e*Eb;//W/m^2
+disp("W/m^2",Eeb,"Total emissive power with emissivity =")
diff --git a/965/CH11/EX11.4/4.sci b/965/CH11/EX11.4/4.sci new file mode 100644 index 000000000..63a049e0d --- /dev/null +++ b/965/CH11/EX11.4/4.sci @@ -0,0 +1,24 @@ +clc;
+clear all;
+disp("Energy emitted by sun")
+T=5750;//K
+ds=1.4*10^9;//m diameter of sun
+de=12.8*10^6;//m diameter of earth
+d=15*10^10;//m distance between earth and sun
+
+rs=ds/2;
+re=de/2;
+sigma=5.67*10^(-8);
+As=4*%pi*rs^2;//m^2 surface area of sun
+Eb=sigma*As*T^4;//W
+disp("W",Eb,"total energy emitted by sun =")
+Eo= Eb/(4*%pi*d^2);
+disp("W/m^2",Eo, "Energy received outside earth''s atmosphere =")
+Ee=Eo*%pi*re^2;
+disp("W/m^2",Ee, "Energy received by earth =")
+x=(1-0.42)*Eo// direct energy reaching the earth
+y=0.22*x// diffusion rate
+z=x+y// total radiation reaching the collector
+ap=1.6*1.6*cos(%pi*40/180)// projected area
+Es=ap*z;
+disp("W",Es,"The energy received by the solar collector =")
diff --git a/965/CH13/EX13.1/1.sci b/965/CH13/EX13.1/1.sci new file mode 100644 index 000000000..c6bf289f9 --- /dev/null +++ b/965/CH13/EX13.1/1.sci @@ -0,0 +1,31 @@ +clc;
+clear all;
+disp("fracion and pressure")
+
+Ma=24;
+Mb=48;
+M=30;
+rho=1.2;// kg/m^3
+T=290;// K
+C=rho/M;// mole concentration of the mixture
+//Ca=C-Cb
+//rhoA+rhoB=rho;
+//rhoA=Ma*Ca
+//rhoB=Mb*Cb
+//24*(C-Cb)+48*Cb=rho
+Cb=(rho-24*C)/24;//kg mole/m^3
+Ca=C-Cb;//kg mole/m^3
+rhoA=Ma*Ca;// kg/m^3
+rhoB=Mb*Cb;// kg/m^3
+xA=Ca/C;
+disp(xA,"mole fraction of A, xA =")
+xB=Cb/C;
+disp(xB,"mole fraction of B, xB =")
+mA=rhoA/rho;
+disp(mA,"mole fraction of A, mA =")
+mB=rhoB/rho;
+disp(mB,"mole fraction of B, mB =")
+G=8.314;// kJ/(kgmole*K)
+p=rho*G*T/M;
+disp("kPa",p,"Total pressure p =")
+
diff --git a/965/CH13/EX13.10/10.sci b/965/CH13/EX13.10/10.sci new file mode 100644 index 000000000..24a1b424e --- /dev/null +++ b/965/CH13/EX13.10/10.sci @@ -0,0 +1,12 @@ +clc;
+clear all;
+disp("Mass transfer coefficient")
+U=6.2;// m/s
+d=35/1000;// m
+v=15.5*10^(-6);//m^2/s
+D=0.82*10^(-5);//m^2/s
+Sc=v/D;// Schmidt No.
+Re=U*d/v;// Reynolds No.
+Sh=0.023*((Re)^0.83)*(Sc)^0.44;
+hm=Sh*D/d;// m/s
+disp("m/s",hm,"mass transfer coefficient = ")
diff --git a/965/CH13/EX13.11/11.sci b/965/CH13/EX13.11/11.sci new file mode 100644 index 000000000..f6cc4549b --- /dev/null +++ b/965/CH13/EX13.11/11.sci @@ -0,0 +1,30 @@ +clc;
+clear all;
+disp("evaporation rate calculation")
+U=2.8;// m/s
+L=300/1000;//m
+rho=1.205;//kg/m^3
+v=15.06*10^(-6);//m^2/s
+D=4.166*10^(-5);//m^2/s
+
+Re=U*L/v;// Reynolds No.
+Re
+if Re<5*10^5
+disp("flow is laminar")
+end
+Sc=v/D;// Schmidt No.
+Sc
+Sh=0.664*((Re)^0.5)*(Sc)^(0.33);
+Sh
+L=320/1000;//m
+hm=Sh*D/L;// m/s
+disp("m/s",hm,"mass transfer coefficient = ")
+disp("mass transfer based on pressure difference ")
+T=15+273;//K
+R=287;
+hmp=hm/(R*T);// m/s
+A=0.32*0.42;//m^2
+pw1=0.017*10^(5);
+pw2=0.0068*10^(5);
+mw=hmp*A*(pw1-pw2)*3600;
+disp("kg/h",mw,"mass diffusion of water =")
diff --git a/965/CH13/EX13.12/12.sci b/965/CH13/EX13.12/12.sci new file mode 100644 index 000000000..f7e6175c2 --- /dev/null +++ b/965/CH13/EX13.12/12.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("molar diffusion flux")
+D=5.2*10^(-6);// m^2/s
+mbl=0.2;//mole of benzene in liquid phase
+mbv=0.55;//mole of benzene in vapor phase
+pv=0.72;//bar vapor pressure of toulene
+p=1;// bar atmospheric pressure
+pt1=(1-mbl)*pv;// bar
+pt2=(1-mbv)*p;// bar
+L=0.35/1000;//m
+G=8314;// gas constant
+T=105+273;// K
+Nt=D*(pt1-pt2)*10^5/(G*L*T);//kg mole/(m^2*s)
+disp("kg mole/(m^2*s)",Nt,"molar diffusion flux of toulene Nt =")
+
+
diff --git a/965/CH13/EX13.13/13.sci b/965/CH13/EX13.13/13.sci new file mode 100644 index 000000000..686c7ea07 --- /dev/null +++ b/965/CH13/EX13.13/13.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("diffusion flux rate")
+p=2.5*10^5;// N/m^2
+r1=12/1000;//m
+r2=24/1000;//m
+T=25+273;//K
+R=4160;//J/(kg.K)
+D=2.1*10^(-8);// m^2/s
+S=0.055*2.5;//m^3/m^3 rubber tubing
+V=S;
+Ch1=p*V/(R*T);// kg/m^3 of rubber tuning
+disp("kg/m^3",Ch1,"at inner surface of pipe Ch1 =")
+Ch2=0;
+L=1;//m
+x=r2-r1;//m
+Am=2*3.1416*L*(r2-r1)/log(r2/r1);//m^2
+disp("m^2",Am,"Am =")
+m=D*(Ch1-Ch2)*Am/x;
+m
+disp("kg/s.m",m,"diffusion flux through the cylinder = ")
+
+
+
+
+
+
diff --git a/965/CH13/EX13.14/14.sci b/965/CH13/EX13.14/14.sci new file mode 100644 index 000000000..7aae69917 --- /dev/null +++ b/965/CH13/EX13.14/14.sci @@ -0,0 +1,37 @@ +clc;
+clear all;
+disp("diffusivity of air")
+A=0.5;//m^2
+pi=2.2;// bar
+pf=2.18;// bar
+T=300;// K
+S=0.072;//m^2
+V=0.028;//m^3
+L=10/1000;//m
+R=287;// gas constant
+
+mi=pi*10^5*V/(R*T);//kg
+mi
+mf=pf*10^5*V/(R*T);//kg
+mf
+ma=mi-mf;//kg
+ma
+Na=ma/(6*24*3600)*A;// kg/(s.m^2)
+Na
+pm=(pi+pf)/2;
+S=0.072*pm;//m^3//m^3 of rubber
+S
+p1=2.19*10^(5);
+p2=1*10^(5);
+V1=0.1577;
+V2=0.072;
+Ca1=p1*V1/(R*T);// kg/m^3
+Ca1
+Ca2=p2*V2/(R*T);// kg/m^3
+Ca2
+//Na=D*(Ca1-Ca2)/L;
+D=Na*L/(Ca1-Ca2);
+
+disp("m^2/s",D,"diffusivity = ")
+
+
diff --git a/965/CH13/EX13.15/15.sci b/965/CH13/EX13.15/15.sci new file mode 100644 index 000000000..3aaaefe3e --- /dev/null +++ b/965/CH13/EX13.15/15.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("rate of diffusion")
+T=273;// K
+D=0.17;// cm^2/s
+Ra=82.06;// cm^2atm/(g mole K)
+A=1;//m^2
+pA1=90/760;// atm
+pA2=20/760;// atm
+pB1=1-pA1;
+pB2=1-pA2;
+pBlm=(pB2-pB1)/log(pB2/pB1);
+G=82.06;
+L=3.5*10^(-3);
+p=1;
+Na=(D*A*p/(Ra*T*L))*(pA1-pA2)/pBlm;
+disp("gm moles/s",Na,"rate of diffusion =")
+
+
+
+
diff --git a/965/CH13/EX13.16/16.sci b/965/CH13/EX13.16/16.sci new file mode 100644 index 000000000..ca8e3587f --- /dev/null +++ b/965/CH13/EX13.16/16.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("Nitrogen diffusion rate ")
+A=1;
+T=25+273;
+L=12/1000;//m
+G=8314;// gas constant
+xB=0.2;
+Dab=16*10^(-6);
+xC=0.1;
+Dac=14*10^(-6);
+xD=0.7;
+Dad=9*10^(-6);
+D=1/(xB/Dab+xC/Dac+xD/Dad);//m^2/s
+p=1.013;
+pN1=0.15;//bar
+pN2=0.08;//bar
+pM1=p-pN1;
+pM2=p-pN2;
+Mn=28;
+mn=(D*A*Mn*p*10^5/(G*T*L))*log(pM2/pM1)
+disp("kg/m^2",mn,"diffusion rate of gaseous mixture =")
+
+
+
+
+
diff --git a/965/CH13/EX13.17/17.sci b/965/CH13/EX13.17/17.sci new file mode 100644 index 000000000..d9f1b200c --- /dev/null +++ b/965/CH13/EX13.17/17.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("time for evaporation")
+A=1;
+T=25+273;
+L=6/1000;//m
+G=8314;// gas constant
+p=1;// bar
+D=0.25*10^(-4);//m^2/s
+Mw=18;
+W=1.8*10^(-3);
+pw1=0.03169;// bar
+
+//W=0.622*pw2/(p-pw2);
+pw2=p/(0.622/W+1)
+
+mw=(D*A*Mw*p*10^5/(G*T*L))*log((p-pw2)/(p-pw1));
+disp("kg/m^2",mw,"diffusion rate of gaseous mixture =")
+d=1.2/1000;//m
+M=A*d*1000;//kg
+t=M/mw;
+disp("h",t/3600,"time required =")
+
+
+
+
+
diff --git a/965/CH13/EX13.2/2.sci b/965/CH13/EX13.2/2.sci new file mode 100644 index 000000000..ad749e77e --- /dev/null +++ b/965/CH13/EX13.2/2.sci @@ -0,0 +1,34 @@ +clc;
+clear all;
+disp("composition determination")
+T=273+15;// K
+G=8314;// kJ/(kgmole*K)
+p=1.1*10^(5);// N/m^2
+pO2=0.21*p;
+pN2=0.79*p;
+
+CO2=pO2/(G*T);// kg mole/m^3
+disp("kg mole/m^3",CO2,"molar concentration of O2, CO2 =")
+CN2=pN2/(G*T);// kg mole/m^3
+disp("kg mole/m^3",CN2,"molar concentration of N2, CN2 =")
+
+MO2=32;
+MN2=28;
+
+rhoO2=MO2*CO2;//kg/m^3
+rhoN2=MN2*CN2;//kg/m^3
+disp("kg/m^3",rhoO2,"molar density of O2 rhoO2 =")
+disp("kg/m^3",rhoN2,"molar density of N2, rhoN2 =")
+
+rho=rhoO2+rhoN2;
+xO2=rhoO2/rho;
+disp(xO2,"mass fraction of O2 xO2 =")
+xN2=rhoN2/rho;
+disp(xN2,"mass fraction of N2, xN2 =")
+
+C=CO2+CN2
+mO2=CO2/C;
+disp(xO2,"mole fraction of O2, mO2 =")
+mN2=CN2/C;
+disp(xN2,"mole fraction of N2, mN2 =")
+
diff --git a/965/CH13/EX13.3/3.sci b/965/CH13/EX13.3/3.sci new file mode 100644 index 000000000..57df0c2fe --- /dev/null +++ b/965/CH13/EX13.3/3.sci @@ -0,0 +1,14 @@ +clc;
+clear all;
+disp("Diffusion coefficient determination")
+MA=17;
+MB=29;
+Va=26.43;// cm^3/gm mole
+Vb=30.6;// cm^3/gm mole
+
+T=273+27;// K
+p=1;// atm
+
+DAB=0.0043*(T^1.5)*(1/MA+1/MB)^0.5/(p*(Va^(1/3)+Vb^(1/3))^2);
+disp("cm^2/s",DAB,"Diffusion coefficient DAB =")
+
diff --git a/965/CH13/EX13.4/4.sci b/965/CH13/EX13.4/4.sci new file mode 100644 index 000000000..e087b6eb6 --- /dev/null +++ b/965/CH13/EX13.4/4.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("Diffusion coefficient determination")
+T=273+27;//K
+sigA=3.996 ;//Angstrom
+eAK=190;//K
+MA=44;
+
+sigB=3.167;//Angstrom
+eBK=97;//K
+MB=29;
+
+sigAB=(sigA+sigB)/2;// Angstrom
+sigAB
+eABK=(eAK*eBK)^0.5;
+eABKT=eABK/T;
+Kt=1/eABKT;
+
+Kt=[2 2.1 2.2 2.3]
+rho=[1.075 1.057 1.041 1.026]
+// By interpolation
+rho=1.057-(1.057-1.041)*(2.195-2.1)/(2.2-2.1)
+p=1;//atm
+
+DAB=0.001858*(T^1.5)*(1/MA+1/MB)^0.5/(p*rho*(sigAB)^2);
+disp("cm^2/s",DAB,"Diffusion coefficient DAB =")
+
diff --git a/965/CH13/EX13.5/5.sci b/965/CH13/EX13.5/5.sci new file mode 100644 index 000000000..ddd3ffc26 --- /dev/null +++ b/965/CH13/EX13.5/5.sci @@ -0,0 +1,12 @@ +clc;
+clear all;
+disp("molar diffusion flux")
+L=16/1000;//m
+CA1=1.2;// kg mole/m^3
+CA2=0;// kg mole/m^3
+Da=0.248*10^(-12);//m^2/s
+
+Na= Da*(CA1-CA2)/L;// kg mole /(m^2*s)
+disp("kg mole /(m^2*s)",Na,"molar diffusion flux rate, Na =")
+
+
diff --git a/965/CH13/EX13.6/6.sci b/965/CH13/EX13.6/6.sci new file mode 100644 index 000000000..937ee4c70 --- /dev/null +++ b/965/CH13/EX13.6/6.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("molar concentration & flux")
+S=0.00145;// kg mole/m^3-bar
+p1=2.4;//bar
+p2=1;//bar
+L=0.3/1000;//m
+D=8.6*10^(-8);// m^2/s
+Ch1=S*p1;// kg mole/m^3
+Ch2=S*p2;// kg mole/m^3
+disp("kg mole/m^3", Ch1,"Molar concentration of hydrogen Ch1 =")
+disp("kg mole/m^3", Ch2,"Molar concentration of hydrogen Ch2 =")
+Nh=D*(Ch1-Ch2)/L;
+disp("kg mole/m^2*s", Nh,"Molar diffusion flux of hydrogen Nh = *")
+
+
+
+
+
+
+
+
diff --git a/965/CH13/EX13.7/7.sci b/965/CH13/EX13.7/7.sci new file mode 100644 index 000000000..e685c0629 --- /dev/null +++ b/965/CH13/EX13.7/7.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("Mass transfer rate")
+L=25;//m
+r=3.5/2000;//m
+pA1=1.01325*10^5;//atm
+pA2=0;//atm
+D=0.3*10^(-4);// m^2/s
+D=D*3600;// m^2/h
+T=27+273;//K
+G=8314;
+A=3.1416*r*r;//m^2
+
+Na=(D*A)/(G*T)*(pA1-pA2)/L;
+disp("kg mole/h",Na,"Rate of diffusion Na =")
+
+MNH3=17;
+Mair=29;
+NNH3=Na*MNH3;
+disp("kg/h",NNH3," mass flow rate of NH3 =")
+
+Nair=Na*Mair;
+disp("kg/h",Nair," mass flow rate of air =")
diff --git a/965/CH13/EX13.8/8.sci b/965/CH13/EX13.8/8.sci new file mode 100644 index 000000000..d95cc9cb1 --- /dev/null +++ b/965/CH13/EX13.8/8.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("time required for evaporation")
+L=15/1000;// m
+T=40+273;// K
+D=0.25*10^(-4);// m^2/s
+pw1=0.07384;// bar
+pw2=0;
+Mw=18;
+A=1;
+G=8314;
+p=1.0132;// N/m^2
+
+mw=(D*A*Mw*p*10^5/(G*T*L))*log((p-pw2)/(p-pw1));//kg/(m^2*s)
+disp("kg/(m^2*s)",mw,"mw = ")
+M=0.015*1*1000;//kg/m^2
+t=M/(mw*3600); //h
+disp("h",t,"time required t = ")
diff --git a/965/CH13/EX13.9/9.sci b/965/CH13/EX13.9/9.sci new file mode 100644 index 000000000..84d292672 --- /dev/null +++ b/965/CH13/EX13.9/9.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("time for evaporation")
+L=2.8/1000;// m
+T=20+273;// K
+D=8.3*10^(-6);// m^2/s
+A=3.1416*(5.5/2)^2;//m^2
+pb1=0.13;// bar
+pb2=0;
+Mb=78;
+p=1.013;//bar
+pa1=p-pb1;//bar
+pa2=p-pb2;//bar
+G=8314;
+rho=880;//kg/m^2
+h=1/1000;//m
+mb=(D*A*Mb*p*10^5/(G*T*L))*log((pa2)/(pa1));//kg/s
+disp("kg/s",mb,"diffusion rate of benzene mb = ")
+M=A*h*rho
+t=M/(mb*60); //h
+disp("min",t,"time required t = ")
diff --git a/965/CH2/EX2.10/10.sci b/965/CH2/EX2.10/10.sci new file mode 100644 index 000000000..813c68a87 --- /dev/null +++ b/965/CH2/EX2.10/10.sci @@ -0,0 +1,10 @@ +clc;
+clear all;
+disp("Heat loss rate")
+L=0.2;//m
+t1=300;// degree C
+t2=30;// degree C
+a=0.3;
+b=5*10^(-6);
+q= (a+(b/3)*(t1*t1+t1*t2+t2*t2))*(t1-t2)/L;// W/m^2 rate of heat transfer
+disp ("W/m^2",q,"rate of heat transfer is = ")
diff --git a/965/CH2/EX2.11/11.sci b/965/CH2/EX2.11/11.sci new file mode 100644 index 000000000..dc5ad899b --- /dev/null +++ b/965/CH2/EX2.11/11.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("Steady state conduction")
+disp("thickness of wall : L")
+disp("temperature of surfaces : t1, t2")
+disp("relation of variation of thermal conductivity : k= k0*t^2")
+disp("i) Expression for heat conduction through wall")
+disp("Heat conduction through plane wall is given by Q = -k*A*dt/dx")
+disp("Heat conduction through plane wall is given by Q = -k0*t^2*A*dt/dx")
+disp("By rearranging and integrating within limits t1 to t2, we get :")
+disp("Required expression, Q =k0*A(t1^3-t2^3)/(3*L)")
+
+disp("ii) Temperature at which mean thermal conductivity be evaluated in order to get the same heat flow by its substitution in simplified Fourier''s equation")
+disp("from above equation k0*A(t1^3-t2^3)/(3*L) = km*A(t1-t2)/L")
+disp("from above equation k0*A(t1^3-t2^3)/(3*L) = k0*tm^2*A(t1-t2)/L")
+disp("thus required temperature is , tm =(((t1^2+t2^2+t1*t2)/3)^0.5")
+
diff --git a/965/CH2/EX2.12/12.sci b/965/CH2/EX2.12/12.sci new file mode 100644 index 000000000..da627203f --- /dev/null +++ b/965/CH2/EX2.12/12.sci @@ -0,0 +1,10 @@ +clc;
+clear all;
+disp("1-D heat flow")
+disp("Fourier''s equation: q = -k*dt/dx")
+disp("k=k0*(1+at+bt^2)")
+disp("q = k0*(1+at+bt^2)*dt/dx")
+disp("q.dx = k0*(1+at+bt^2)*dt")
+disp("integrating above equation within limits t1 to t2")
+disp("the required expression is, q = -k*(t2-t1)*(1+a*(t1+t2)/2+b*(t1^2+t2^2+t1*t2)/3)/L")
+
diff --git a/965/CH2/EX2.13/13.sci b/965/CH2/EX2.13/13.sci new file mode 100644 index 000000000..5cc2a4ccf --- /dev/null +++ b/965/CH2/EX2.13/13.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("pipe location distance")
+L=1.2;//m thickness of wall
+// temperature of wall surfaces
+t1= 200;// degree C
+t2=60;// degree C
+t= 120;// degree C
+//k= 0.28*(1+0.036*t);// thermal conductivity relation
+// rate of heat transfer Q= km*(A/L)*(t1-t2)
+// 0.28*(1+(0.036/2)*(200+60))*(A/1.2)*(200-60)=0.28*(1+(0.036/2)*(200+120))*(A/x)*(200-120)
+x=151.42/185.54;//m
+disp("m",x,"the distance at which the pipe should be imbedded from hot surface = ")
+
+
+
diff --git a/965/CH2/EX2.14/14.sci b/965/CH2/EX2.14/14.sci new file mode 100644 index 000000000..05bc8ccae --- /dev/null +++ b/965/CH2/EX2.14/14.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("steady state flux")
+t1=600;// degree C
+t3=300;// degree C
+La=0.05;//m
+Lb=0.1;//m
+//kmA=0.05*(1+0.0065*(t1+t2)/2)
+//kmB=0.04*(1+0.0075*(t3+t2)/2)
+// q= Q/A=(t1-t2)/(La/kmA)=(t2-t3)/(Lb/kmB)
+// (600-t2)/(0.05/(0.05*(1+0.0065*(600+t2)/2)))=(t2-300)/(0.1/(0.04*(1+0.0075*(300+t2)/2)))
+//t2^2+294.7*t2-426315=0
+t2=(-294.7+(294.7^2+4*426316)^(0.5))/2
+kmA=0.05*(1+0.0065*(t1+t2)/2);// W/(m*C)
+disp (kmA,"thermal conductivity of A = ")
+ q=(t1-t2)/(La/kmA);
+ disp ("W/m^2",q,"rate of heat transfer = ");
+
diff --git a/965/CH2/EX2.15/15.sci b/965/CH2/EX2.15/15.sci new file mode 100644 index 000000000..e326f59fe --- /dev/null +++ b/965/CH2/EX2.15/15.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("temperature at interface")
+La=0.12;//m
+Lb=0.6;//m
+//kA=0.25*(1+0.0009*t)
+kB=0.8;// W/(m*C)
+t1=1250;// degree C
+tair=40;// degree C
+delT=(t1-tair);
+//kAm=0.25*(1+0.0009*(t2+1250)/2)
+A=1;// area
+//RthA= La/(kAm*A); thermal resistivity of fire clay
+RthB= Lb/(kB*A); //thermal resistivity of re4d brick
+//heat loss for 1 m^2 furnace wall = Q = delT/(RthA+RthB)=(t2-40)/0.8
+//1210/(1/(2.083+0.000937*(1250+t2))+0.75)=(t2-40)/0.8
+//0.000703*(t2^2)+2.505*t2-3287.47
+t2=(-2.505+(2.505^2+4*0.000703*3287.47)^0.5)/(2*0.000703);
+disp ("degree C", t2, "temperature t2 = ")
+Q=(t2-40)/RthB;
+disp ("W",Q,"heat loss = ")
+
+
diff --git a/965/CH2/EX2.16/16.sci b/965/CH2/EX2.16/16.sci new file mode 100644 index 000000000..6054d7ded --- /dev/null +++ b/965/CH2/EX2.16/16.sci @@ -0,0 +1,26 @@ +clc;
+clear all;
+disp("heat flow rate")
+La=0.03;//m
+Aa=0.1*0.1;//m^2
+kA= 150;//W/(m*C)
+RthA=La/(kA*Aa);
+Lb=0.08;//m
+Ab=0.1*0.03;//m^2
+kB= 30;//W/(m*C)
+RthB=Lb/(kB*Ab);
+Lc=0.08;//m
+Ac=0.1*0.07;//m^2
+kC= 65;//W/(m*C)
+RthC=Lc/(kC*Ac);
+Ld=0.05;//m
+Ad=0.1*0.1;//m^2
+kD= 50;//W/(m*C)
+RthD=Ld/(kD*Ad);
+Req=RthB*RthC/(RthB+RthC);
+Rtotal=RthA+Req+RthD
+t1=400;// degree C
+t2=60;// degree C
+Q=(t1-t2)/Rtotal;
+disp ("W",Q,"heat transfer = ")
+
diff --git a/965/CH2/EX2.17/17.sci b/965/CH2/EX2.17/17.sci new file mode 100644 index 000000000..f156db400 --- /dev/null +++ b/965/CH2/EX2.17/17.sci @@ -0,0 +1,33 @@ +clc;
+clear all;
+disp ("(i)When the layers are glued")
+A=1
+kA=0.12;//W/(m*C)
+kB=0.02;//W/(m*C)
+kC=0.12;//c
+La=0.02;//m
+RthA=La/(kA*A);
+Lb=0.1;//m
+RthB=Lb/(kB*A);
+Lc=0.02;//m
+RthC=Lc/(kC*A);
+t1=35;// degree C
+t4=20;// degree C
+Rtotal=RthA+RthB+RthC;
+q=(t1-t4)/Rtotal;//W/m^2
+disp ("W/m^2",q,"heat flow per m^2 area = ")
+disp ("(ii)When the layers are joined by steel bolts")
+n=4;// number of bolts
+dB=0.01 ;//m diameter of bolt
+A=3.14*(dB^2)/4;// m^2
+kD=40;//W/(m*C)
+RthD=(La+Lb+Lc)/(kD*A);// C/W
+Rtotal=(RthA+RthB+RthC)*RthD/(4*(RthA+RthB+RthC)+RthD);
+q=(t1-t4)/Rtotal;//W/m^2
+disp ("W/m^2",q,"heat flow per m^2 area = ")
+
+
+
+
+
+
diff --git a/965/CH2/EX2.18/18.sci b/965/CH2/EX2.18/18.sci new file mode 100644 index 000000000..9a1b3a8eb --- /dev/null +++ b/965/CH2/EX2.18/18.sci @@ -0,0 +1,38 @@ +clc;
+clear all;
+disp("composite wall system")
+La=0.12;//m
+Aa=1;//m^2
+kA= 14.5;//W/(m*C)
+RthA=La/(kA*Aa);
+
+La1=0.000025;//m
+Aa1=0.15;//m^2
+kA1= 14.5;//W/(m*C)
+RthA1=La1/(kA1*Aa1);
+
+Lb=0.12;//m
+Ab=1;//m^2
+kB= 210;//W/(m*C)
+RthB=Lb/(kB*Ab);
+
+Lb1=0.000025;//m
+Ab1=0.15;//m^2
+kB1= 210;//W/(m*C)
+RthB1=Lb1/(kB1*Ab1);
+
+Lc=0.000025;//m
+Ac=0.7;//m^2
+kC=0.032;//W/(m*C)
+RthC=Lc/(kC*Ac);
+
+Req=RthA1*RthB1*RthC/(RthA1*RthC+RthB1*RthA1+RthB1*RthC);
+
+Rtotal=RthA+Req+RthB
+t1=220;// degree C
+t2=30;// degree C
+Q=(t1-t2)/Rtotal;
+disp ("W",Q,"heat transfer = ")
+delT=Q*Req;
+disp("degree C",delT,"temperature drop in contact")
+
diff --git a/965/CH2/EX2.19/19.sci b/965/CH2/EX2.19/19.sci new file mode 100644 index 000000000..8c8fbba31 --- /dev/null +++ b/965/CH2/EX2.19/19.sci @@ -0,0 +1,15 @@ +clc;
+clear all;
+disp("heat loss rate")
+L=0.012;// m
+Thf=95;// degree C
+Tcf=15;// degree C
+k=50;// W/(m*C)
+hhf=2850;// W/(m^2*C)
+hcf=10;// W/(m^2*C)
+U=1/(1/hhf+1/hcf+L/k);
+q=U*(Thf-Tcf);
+disp("W/m^2",q,"rate of heat loss per m^2 of the tank surface area = ")
+//q=hcf*(t2-tcf)
+t2=q/hcf+Tcf;
+disp("degree C",t2,"temperature of the outside surface of the tank = ")
diff --git a/965/CH2/EX2.2/2.sci b/965/CH2/EX2.2/2.sci new file mode 100644 index 000000000..60890c9f0 --- /dev/null +++ b/965/CH2/EX2.2/2.sci @@ -0,0 +1,9 @@ +clc;
+clear all;
+disp("Heat transfer rate")
+t1=60;// degree C temperature of inner surface of the wall
+t2=35;// degree C temperature of outer surface of the wall
+L=0.22;// m thickness of the wall
+k=0.51;// W/m*C thermal conductivity of the brick
+q = k*(t1-t2)/L ;// = Q/A W/m^2 rate of heat transfer
+disp ("W/m^2",q,"the heat transfer rate is = ")
diff --git a/965/CH2/EX2.20/20.sci b/965/CH2/EX2.20/20.sci new file mode 100644 index 000000000..63fb7772a --- /dev/null +++ b/965/CH2/EX2.20/20.sci @@ -0,0 +1,14 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+Theater=350;// degree C
+Tsolution=95;// degree C
+xCI=0.025;///m
+xenamel=0.8*10^(-3);//m
+hsol=5.5*10^(3);//W/(m^2*K)
+kCI=50;//W/(m*K)
+kenamel=1.05;//W/(m*K)
+U=1/(xCI/kCI+xenamel/kenamel+1/hsol);
+disp("W/(m*K)",U,"overall heat transfer coefficient U= ")
+Q=U*(Theater-Tsolution);
+disp("kW/m^2",Q/1000,"rate of heat transfer per unit area = ")
diff --git a/965/CH2/EX2.21/21.sci b/965/CH2/EX2.21/21.sci new file mode 100644 index 000000000..a9ba45054 --- /dev/null +++ b/965/CH2/EX2.21/21.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("thickness of insulation")
+ti=310;// degree C
+t0=45;// degree C
+//tair=12 to 32 degree C
+k=0.036;//W/(m*C)
+h0=12;//W/(m^2*C)
+//q=Q/A=(ti-tair)/(L/k+1/h0);
+//(ti-tair)/(L/k+1/h0)=(t0-tair)/(1/h0);
+//L=(k/h0)*(ti-t0)t/(t0-tair)
+disp ("thickness of insulation will be large for tair = 32 degree C")
+tair=32;// degree C
+L=(k/h0)*(ti-t0)/(t0-tair);
+disp("mm",L*1000,"thickness of insulation = ")
+
diff --git a/965/CH2/EX2.22/22.sci b/965/CH2/EX2.22/22.sci new file mode 100644 index 000000000..e33ce024e --- /dev/null +++ b/965/CH2/EX2.22/22.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("upper surface temperature")
+thf=1020;// temperature of hot gases
+L=1.2*10^(-3);// thickness of blade
+k=12;//W/(m*C)
+A=1;// area
+hhf=2750;//W/(m^2*C) heat transfer coefficients
+hcf=1400;//W/(m^2*C) heat transfer coefficients
+t1=900;// temperature of the upper surface
+Q=hhf*A*(thf-t1);//W/m^2 rate of heat transfer per unit area
+disp ("W/m^2",Q,"rate of heat transfer per unit area = ")
+//Q=k*A*(t1-t2)/L;
+t2=t1-(Q*L/(k*A));
+disp("degree C",t2,"t2 is =")
+//Q=hcf*A*(t2-tcf)
+tcf=t2-(Q/(hcf*A));
+disp("degree C",tcf,"tcf is =")
+
+
+
+
+
diff --git a/965/CH2/EX2.23/23.sci b/965/CH2/EX2.23/23.sci new file mode 100644 index 000000000..c15db4cce --- /dev/null +++ b/965/CH2/EX2.23/23.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+disp("heat transfer rate")
+A=1;
+thf=100;// temperature of hot fluid
+tcf=25;// temperature of cold fluid
+L=4*10^(-3);// thickness of blade
+k=95.5;//W/(m*C)
+hhf=14500;//W/(m^2*C) heat transfer coefficients
+hcf=2250;//W/(m^2*C) heat transfer coefficients
+Rthhf=(1/hhf);
+Rthcf=(1/hcf);
+Rth12=L/k;
+Rtotal=Rthhf+Rthcf+Rth12;
+q=(thf-tcf)/Rtotal;//W/m^2 rate of heat transfer per unit area
+disp ("W/m^2",q,"i)rate of heat transfer per unit area = ")
+//Q=U*A*(thf-tcf)/L;
+U=q/(A*(thf-tcf));
+disp("W/(m^2*C)",U,"ii)overall heat transfer coefficient =")
+//q=delT/Rhfthhf
+delThf=q*Rthhf;
+disp("degree C",delThf,"temperature drop in vapour film =")
+//q=delT12/Rth12
+delT12=q*Rth12;
+disp("degree C",delT12,"temperature drop in metal =")
+//q=delTcf/Rthcf
+delTcf=q*Rthcf;
+disp("degree C",delTcf,"temperature drop in water film =")
+
diff --git a/965/CH2/EX2.24/24.sci b/965/CH2/EX2.24/24.sci new file mode 100644 index 000000000..f0678f5ca --- /dev/null +++ b/965/CH2/EX2.24/24.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("rate of heat removal")
+La=0.003;//m
+Lb=0.05;//m
+Lc=0.003;//m
+kA=46.5;//W/(m*C)
+kB=0.046;//W/(m*C)
+kC=46.5;//W/(m*C)
+h0=11.6;//W/(m^2*C)
+hi=14.5;//W/(m^2*C)
+t0=25;// degree C temperature
+ti=6;// degree C temperature
+A=0.5*0.5*2+0.5*1*4;
+Q=A*(t0-ti)/(1/h0+La/kA+Lb/kB+Lc/kC+1/hi);
+disp("W",Q,"rate of heat removal = ")
+//Q=h0*A*(25-t1)
+t1=25-Q/(h0*A);// degree C temperature of outer surface
+disp ("degree C",t1,"temperature of outer surface of metal sheet= ")
+
diff --git a/965/CH2/EX2.25/25.sci b/965/CH2/EX2.25/25.sci new file mode 100644 index 000000000..6e23da513 --- /dev/null +++ b/965/CH2/EX2.25/25.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("heat flux calculation")
+La=0.2;//m thickness of chrome bricks
+Lb=0.1;//m thickness of kaolin bricks
+Lc=0.1;//m thickness of masonary bricks
+kA=1.25;//W/(m*C)
+kB=0.074;//W/(m*C)
+kC=0.555;//W/(m*C)
+hhf=74;//W/(m^2*C)
+thf=1670;// degree C temperature of hot fluid
+t4=70;// temperature of outer surafce
+q= (thf-t4)/(1/hhf+La/kA+Lb/kB+Lc/kC);
+disp("W/m^2",q,"rate of heat flow per m^2 = ")
+//q=(thf-t1)/(1/hhf)=(t1-t2)/(La/kA)=(t2-t3)/(Lb/kB)
+t1=thf-q/hhf;
+disp ("degree C",t1,"temperature t1 = ")
+t2=t1-q*La/kA;
+disp ("degree C",t2,"temperature t2 = ")
+t3=t2-q*Lb/kB;
+disp ("degree C",t3,"temperature t3 = ")
diff --git a/965/CH2/EX2.26/26.sci b/965/CH2/EX2.26/26.sci new file mode 100644 index 000000000..58e38dfef --- /dev/null +++ b/965/CH2/EX2.26/26.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("Heat removal by refrigeration")
+La=0.22;//m thickness of brick wall
+Lb=0.09;//m thickness of plastic foam
+Lc=0.016;//m thickness of wood
+thf=25;// degree C temperature of hot fluid
+tcf=-3;// degree C temperature of cold fluid
+kA=0.99;//W/(m*C)
+kB=0.022;//W/(m*C)
+kC=0.17;//W/(m*C)
+A=85;//m^2
+hhf=11;//W/(m^2*C) hot fluid
+hcf=30;//W/(m^2*C) cold fluid
+U=1/(1/hhf+La/kA+Lb/kB+Lc/kC+1/hcf)
+Q= U*A*(thf-tcf);
+disp("W/m^2",Q,"rate of heat flow per m^2 = ")
+//Q=U*A*(thf-t2)
+U=1/(1/hhf+La/kA);
+t2=thf-Q/(U*A);
+disp ("degree C",t2,"temperature of inside surface of brick t2 = ")
+
diff --git a/965/CH2/EX2.27/27.sci b/965/CH2/EX2.27/27.sci new file mode 100644 index 000000000..2d986c639 --- /dev/null +++ b/965/CH2/EX2.27/27.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("thickness of layer")
+L=0.55;//m
+kA=2.3;//W/(m*K)
+kB=0.2;//W/(m*K)
+thf=900;// degree C
+t2=520;// degree C
+hhf=230;//W/(m^2*C)
+hcf=46;//W/(m^2*C)
+tcf=30;// degree C
+//q=(thf-t2)/(1/hhf+La/kA)=(t2-tcf)/(1/hcf+(0.55-La)/kB)
+La=1051.13/2113;//m
+Lb=L-La;//m
+disp ("mm",La*10^3,"La=")
+disp ("mm",Lb*10^3,"Lb=")
+q=(thf-t2)/(1/hhf+La/kA);
+disp("W/m^2",q,"rate of heat transfer = ")
+
diff --git a/965/CH2/EX2.28/28.sci b/965/CH2/EX2.28/28.sci new file mode 100644 index 000000000..6e6100f18 --- /dev/null +++ b/965/CH2/EX2.28/28.sci @@ -0,0 +1,13 @@ +clc;
+clear all;
+disp("Heat transfer flux")
+L=0.2;//m
+t1=1350;// degree C
+tcf=40;// degree C
+k=1.35;// W/(m*C)
+//q=(t1-t2)/(L/k)=(t2-tcf)/(1/h)
+//(1350-t2)/(0.2/1.35)=(t2-40)*(7.85+0.08*(t2-40))
+//t2^2+102.5*t2-116231=0
+t2=(-102.5+(102.5^2+4*116231)^0.5)/2;
+q=(t1-t2)/(L/k);
+disp("W/m^2",q,"rate of heat transfer = ")
diff --git a/965/CH2/EX2.29/29.sci b/965/CH2/EX2.29/29.sci new file mode 100644 index 000000000..3959570a5 --- /dev/null +++ b/965/CH2/EX2.29/29.sci @@ -0,0 +1,42 @@ +clc;
+clear all;
+disp("interface temperature")
+La=0.12;//m
+Lb=0.12;//m
+Lc=0.012;//m
+
+hcf=18;//W/(m^2*C)
+
+kA=1.6;//W/(m*C)
+kB=0.3;//W/(m*C)
+kC=0.14;//W/(m*C)
+
+Rair=0.16;//K/W
+
+thf=1090;// degree C temperature
+tcf=20;// degree C temperature
+
+Rtotal =(La/kA)+Rair+(Lb/kB)+(Lc/kC)+1/hcf
+
+q=(thf-tcf)/Rtotal;
+
+disp("W",q,"rate of heat flow per m^2 surface area = ")
+
+
+//q=(thf-t2)/(La/kA)
+t2=thf-q*(La/kA);
+disp ("degree C",t2,"t2 = ")
+
+//q=(t2-t3)/(Rair)
+t3=t2-q*(Rair);
+disp ("degree C",t3,"t3 = ")
+
+//q=(t3-t4)/(Lb/B)
+t4=t3-q*(Lb/kB);
+disp ("degree C",t4,"t4= ")
+
+
+//q=(t4-t5)/(Lc/kC)
+t5=t4-q*(Lc/kC);
+disp ("degree C",t5,"t5 = ")
+
diff --git a/965/CH2/EX2.3/3.sci b/965/CH2/EX2.3/3.sci new file mode 100644 index 000000000..c1690409e --- /dev/null +++ b/965/CH2/EX2.3/3.sci @@ -0,0 +1,9 @@ +clc;
+clear all;
+disp("Net heat flux")
+t1=100;// degree C temperature of one surface of the slab
+t2=0;// degree C temperature of another surface of the slab
+L=0.25;// m thickness of the wall
+k=387.6;// W/(m*K) thermal conductivity of the brick
+q = k*(t1-t2)/L ;// = Q/A W/m^2 rate of heat transfer
+disp ("W/m^2",q,"the heat transfer rate is = ")
diff --git a/965/CH2/EX2.30/30.sci b/965/CH2/EX2.30/30.sci new file mode 100644 index 000000000..3f950e74b --- /dev/null +++ b/965/CH2/EX2.30/30.sci @@ -0,0 +1,42 @@ +clc;
+clear all;
+disp("unknown thermal conductivity")
+La=250/1000;//m
+Lb=100/1000;//m
+Lc=150/1000;//m
+
+hhf=25;//W/(m^2*C)
+hcf=12;//W/(m^2*C)
+
+kA=1.65;//W/(m*C)
+kC=9.2;//W/(m*C)
+
+
+thf=1250;// degree C temperature
+t1=1100;// degree C temperature
+
+q=(thf-t1)*hhf;//W/m^2
+disp("W/m^2",q,"rate of heat transfer = ")
+//q=(delT)/Rtotal;
+
+//Rtotal =(La/kA)+1/hhf+(Lb/kB)+(Lc/kC)+1/hcf;
+//3750(0.289+0.1/kB)=1225;
+kB=0.1/0.0355;
+disp("W/(m*C)",kB,"thermal conductivity = ")
+
+Rtotal =(La/kA)+1/hhf+(Lb/kB)+(Lc/kC)+1/hcf;
+U=1/(Rtotal);
+disp("W/(m^2*C)",U,"overall heat transfer coefficient = ")
+
+//q=(tcf-t2)/(La/kA)
+t2=t1-q*(La/kA);
+disp ("degree C",t2,"t2 = ")
+
+//q=(t2-t3)/(Lb/kB)
+t3=t2-q*(Lb/kB);
+disp ("degree C",t3,"t3 = ")
+
+//q=(t3-t4)/(Lc/kC)
+t4=t3-q*(Lc/kC);
+disp ("degree C",t4,"t4 = ")
+
diff --git a/965/CH2/EX2.31/31.sci b/965/CH2/EX2.31/31.sci new file mode 100644 index 000000000..95e5e0992 --- /dev/null +++ b/965/CH2/EX2.31/31.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("Maximum system temperature")
+La=0.02;//m
+Lb=0.01;//m
+kA=50;//W/(m*C)
+kB=0.2;//W/(m*C)
+h1=200;//W/(m^2*C)
+h2=50;//W/(m^2*C)
+A=0.15*0.15;//m^2
+A
+Q=1000;//W rating of heater
+Q
+ta=25;// degree C
+//Q=A*(Tmax-ta)*(1/(La/kA+1/h1)+1/(Lb/kB+1/h2))
+Tmax=Q/(A*(1/(La/kA+1/h1)+1/(Lb/kB+1/h2)))+ta;
+disp("degree C",Tmax,"Tmax =")
+
+disp("To find outer surface temperature of two slabs")
+//QA=kA*A*(tmax-t1)/La=h1*A*(t1-ta)
+t1=249.8/1.08;
+disp("degree C",t1,"temperature t1 =")
+//QB=kB*A*(tmax-t2)/La=h2*A*(t2-ta)
+t2=310.3/3.5;
+disp("degree C",t2,"temperature t2 =")
+
+
diff --git a/965/CH2/EX2.32/32.sci b/965/CH2/EX2.32/32.sci new file mode 100644 index 000000000..150420d62 --- /dev/null +++ b/965/CH2/EX2.32/32.sci @@ -0,0 +1,41 @@ +clc;
+clear all;
+disp("thickness of layer")
+La=0.25;//m
+//kA=0.28*(1+0.000833*t);//W/(m*C)
+//kB=0.113*(1+0.000206*t);//W/(m*C)
+hhf=30;//W/(m^2*C)
+hcf=10;//W/(m^2*C)
+thf=1300;// degree C
+tcf=30;// degree C
+q=750;// W/m^2 loss of heat to the surroundings
+
+//q=(thf-t1)/(1/hhf)=(t3-tcf)/(1/hcf)=(t1-t2)/(La/kmA)=(t2-t3)/(Lb/kmB)
+//kmA=0.28*(1+0.000833*(t1+t2)/2);//W/(m*C)
+//kmB=0.113*(1+0.000206*(t2+t3)/2);//W/(m*C)
+
+t1=thf-q*(1/hhf);// degree C
+disp("degree C",t1,"t1=")
+
+t3=tcf+q*(1/hcf);// degree C
+disp("degree C",t3,"t3=")
+
+//(t3-tcf)*hcf=kmA*(t1-t2)/La
+//(t3-tcf)*hcf=0.28*(1+0.000833*(t1+t2)/2)*(t1-t2)/La
+//-0.0004165*(t2^2)+t2-1282.5=0
+X=4*0.0004165*1282.5;
+Y=(1+X)^0.5;
+Z=(-1+Y)/(2*0.0004165);
+t2=Z;
+//t2=(-1+(1+4*0.0004165*1282.5)*0.5)/(2*0.0004165);
+disp("degree C",Z,"t2 =")
+
+t=(t1+t2)/2
+kmA=0.28*(1+0.000833*(t1+t2)/2);//W/(m*C)
+disp("W/(m*C)",kmA,"kmA =")
+kmB=0.113*(1+(0.000206/2)*(t2+t3));//W/(m*C)
+disp("W/(m*C)",kmB,"kmB =")
+
+//kmA*(t1-t2)/La=kmB*(t2-t3)/Lb
+Lb=(kmB/kmA)*La*(t2-t3)/(t1-t2);
+disp("mm",Lb*1000,"Lb = ")
diff --git a/965/CH2/EX2.33/33.sci b/965/CH2/EX2.33/33.sci new file mode 100644 index 000000000..8dfc0162f --- /dev/null +++ b/965/CH2/EX2.33/33.sci @@ -0,0 +1,37 @@ +clc;
+clear all;
+disp("temperature profile in furnace")
+thf=810;// degree C
+t1=808;// degree C
+t2=777;// degree C
+t3=78.5;// degree C
+t4=78.4;// degree C
+tcf=26;// degree C
+La=6.5/100;//m
+Lb=12/100;//m
+Lc=0.65/100;//m
+kA=1.13;// W/(m*C)
+efb=0.82;
+sigma=5.67*10^(-8);// W/(m^2*K^4)
+disp("i)rate of heat transfer per unit area of furnace wall")
+//q=qhf=qA=qB=qC=qcf
+q=(t1-t2)/(La/kA);// W/(m^2)
+disp("W/m^2",q,"rate of heat transfer per unit area of furnace wall, q = ")
+qA=q;// W/(m^2)
+
+disp("ii)Thermal conductivities of block insulation kB and kC")
+kB=q*Lb/(t2-t3);// W/(m*C)
+disp("W/(m*C)",kB,"Thermal conductivity of block insulation, kB =")
+
+kC=q*Lc/(t3-t4);// W/(m*C)
+disp("W/(m*C)",kC,"Thermal conductivity of block insulation, kC =")
+
+ho=q/(t4-tcf);
+disp("W/(m^2*C)",ho,"Combined convective and radiative heat transfer coefficient on the outside surface =")
+qrad=efb*sigma*((thf+273)^4-(t1+273)^4);
+disp("W/m^2",qrad,"Heat exchange by radiation = ")
+//q=qrad+qconv
+qconv=q-qrad
+disp("W/(m^2*C)")
+hi=qconv/(thf-t1);
+disp("W/(m^2*C)",hi,"convectiv heat transfer coefficient for the inside surface of furnace wall hconv =")
diff --git a/965/CH2/EX2.34/34.sci b/965/CH2/EX2.34/34.sci new file mode 100644 index 000000000..6dd6c1fa1 --- /dev/null +++ b/965/CH2/EX2.34/34.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("heat transfer rate")
+La=0.22;//m
+Lb=0.22;//m
+kA=3.5;// W/(m*C)
+kB=0.65;// W/(m*C)
+thf=1300;// degree C
+tcf=40;// degree C
+hconvi=16.4;//W/(m^2*C)
+hconvo=11.5;//W/(m^2*C)
+hradi=17.5;//W/(m^2*C)
+hrado=7.2;//W/(m^2*C)
+//q= qconvi+qradi=qA+qB=qconvo+qrado
+//q=delT/Rtotal=(thf-tcf)/Rtotal
+hi=hconvi+hradi;
+ho=hconvo+hrado;
+Rtotal=1/hi+1/ho+La/kA+Lb/kB;
+q=(thf-tcf)/Rtotal;// W
+disp("W/m^2",q,"rate of heat transfer through wall are unit area =")
+//q=hi*(thf-t1)=(t1-t2)/(La/kA)
+t1=thf-q/hi;// degree C
+t2=t1-q*(La/kA);// degree C
+disp ("degree C",t2,"maximum temperature to which common brick is subjected t2 =")
+
+
+
diff --git a/965/CH2/EX2.35/35.sci b/965/CH2/EX2.35/35.sci new file mode 100644 index 000000000..3980db2aa --- /dev/null +++ b/965/CH2/EX2.35/35.sci @@ -0,0 +1,11 @@ +clc;
+clear all;
+disp("heat loss per length")
+r1=10*10^(-3);//m
+r2=20*10^(-3);//m
+r3=(20+30)*10^(-3);//m
+t1=600;// degree C
+t3=1000;// degree C
+kB=0.2;// W/(m*C)
+Ql=2*3.1416*(t1-t3)/((log (r3/r2))/kB);
+disp("W/m",Ql,"heat transfer per unit length = ")
diff --git a/965/CH2/EX2.36/36.sci b/965/CH2/EX2.36/36.sci new file mode 100644 index 000000000..a5254b8d8 --- /dev/null +++ b/965/CH2/EX2.36/36.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("interface temperature calculation")
+r1=25;//mm
+r2=r1+6.4;//mm
+r3=r2+25;//mm
+t1=393;// degree K
+t3=311;// degree K
+kA=0.166;// W/(m*C)
+kB=0.0485;// W/(m*C)
+Ql=2*3.1416*(t1-t3)/((log (r3/r2))/kB+(log (r2/r1))/kA);
+disp("W/m",Ql,"heat transfer per unit length = ")
+//Ql=2*3.1416*(t1-t2)/((ln (r2/r1))/kA;
+t2=t1-Ql*((log (r2/r1))/kA)/(2*3.146);
+disp("degree C",t2-273,"interface temperature between asbestos and fibre glass =")
+
diff --git a/965/CH2/EX2.37/37.sci b/965/CH2/EX2.37/37.sci new file mode 100644 index 000000000..828d84214 --- /dev/null +++ b/965/CH2/EX2.37/37.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("thermal conductivity of gas")
+ rt=10^(-3);//m inside radius of tube
+ L=0.25;//m length of tube
+ rw=0.025*10^(-3);// m radius of electric wire
+ tt=150;// degree C inside tube temperature
+ tw=175;// degree C wire temperature
+ I=0.5;// A current through element
+ V=4;// V voltage across element
+ Q=V*I;// W
+ disp("W",Q,"heat transfer rate =")
+ //Q=2*3.1416*L*k*(tw-tt)/log(rt/rw)
+ X=(2*3.1416*L*(tw-tt)/log(rt/rw))
+ k=Q/X;// thermal conductivity of the gas
+ disp("W/(m*C)",k,"thermal conductivity of the gas =")
+
+
diff --git a/965/CH2/EX2.38/38.sci b/965/CH2/EX2.38/38.sci new file mode 100644 index 000000000..15dea1f31 --- /dev/null +++ b/965/CH2/EX2.38/38.sci @@ -0,0 +1,24 @@ +clc;
+clear all;
+disp("minimum thickness of insulation")
+r1=25*10^(-3);//m
+r2=(55/2)*10^(-3);//m
+t2=300;// degree C
+t3=100;// degree C
+kA=20;// W/(m*C)
+kB=0.02;// W/(m*C)
+Ql=600;// W/m
+//Ql=2*3.1416*(t2-t3)/((log (r3/r2))/kB);
+X=2*3.1416*(t2-t3)*kB;
+Y=X/Ql;
+r3=r2*exp(Y);
+//r3=r2*exp((Ql/kB)/(2*3.14*(t2-t3)));
+r3 = 0.1*ceil(r3*10000)
+disp("mm",r3,"radius =")
+t = r3-r2*1000
+r1 = r1*1000;
+r2 = r2*1000;
+disp("mm",t,"minimum thickness of insulation required t =")
+//Ql=2*3.1416*(t1-t2)/((log (r2/r1))/kA);
+t1=Ql*(log (r2/r1)/kA)/(2*3.1416)+t2;
+disp("degree C",t1,"temperature of inside surface of pipe =")
diff --git a/965/CH2/EX2.39/39.sci b/965/CH2/EX2.39/39.sci new file mode 100644 index 000000000..11dad8cb6 --- /dev/null +++ b/965/CH2/EX2.39/39.sci @@ -0,0 +1,24 @@ +clc;
+clear all;
+disp("Heat loss in pipe")
+ri=0.04;//m inner radius of pipe
+ro=0.05;//m outer radius of pipe
+ti=160;// degree C temperature of hot gases
+to=25;// degree C temperature of space in which the pipe is located
+k=180;// W/(m*C)
+L=1;//m
+
+Q=(ti-to)/(log(ro/ri)/(2*3.1416*k*L))
+disp("W/m",Q,"the heat loss through pipe per unit length =")
+
+r=(ri+ro)/2;//m midway between inner and outer surfaces
+r
+disp("m")
+R=(log(r/ri))/(2*3.1416*k)
+t=ti-Q*R;
+disp("degree C",t,"temperature at a point halfway inner radius of pipe =")
+
+Am=2*3.1416*L*(ro-ri)/log(ro/ri);//m^2
+disp("m^2",Am,"equivalent log-mean area =")
+
+
diff --git a/965/CH2/EX2.4/4.sci b/965/CH2/EX2.4/4.sci new file mode 100644 index 000000000..5125628de --- /dev/null +++ b/965/CH2/EX2.4/4.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("Thickness of brick")
+t1=1325;// degree C
+t2=1200;// degree C
+t3=25 ;// degree C
+L=0.32;// m
+kA=0.84 ;// W/(m*C)
+kB=0.16 ;// W/(m*C)
+// q = (t1-t3)/(La/kA +Lb/kB) = (t1-t2)/(La/kA)=(t2-t3)/(Lb/kB)
+//(1325-25)/(La/0.84+Lb/0.16)=(1325-1200)/(La/0.84)
+//(1325-25)/(La/0.84+(L-La)/0.16)=(1325-1200)/(La/0.84)
+//1300/(1.19La+2-6.25La)=105/La
+La=210/(1300+531.3);//m
+Lb=L-La;//m
+disp("mm",Lb*1000,"thickness of insulation is = ")
+q=(t1-t2)/(La/kA);// W/m*m
+disp("W/m^2",q,"heat loss per unit area is = ")
+
diff --git a/965/CH2/EX2.40/40.sci b/965/CH2/EX2.40/40.sci new file mode 100644 index 000000000..e499875ed --- /dev/null +++ b/965/CH2/EX2.40/40.sci @@ -0,0 +1,26 @@ +clc;
+clear all;
+disp("heat loss per hour")
+r1=120;//mm
+r2=r1+50;//mm
+r3=r2+40;//mm
+kA=0.092;//W/(m*C)
+kB=0.062;//W/(m*C)
+t1=390;// degree C
+t3=40;// degree C
+L=210;//m
+Q1=2*3.1416*L*(t1-t3)/((log(r2/r1))/kA+(log (r3/r2))/kB);
+Q=(3600/1000)*2*3.1416*L*(t1-t3)/((log(r2/r1))/kA+(log (r3/r2))/kB);
+disp("kJ/hr",Q,"total heat loss per hour =")
+X=2*3.1416*r1*L
+qp=Q*1000/X;
+disp("kJ/(m^2*hr)",qp,"total heat loss per m^2 of pipe surface =")
+
+qo=Q*1000/(2*3.1416*r3*L);
+disp("kJ/(m^2*hr)",qo,"total heat loss per m^2 of outer surface =")
+
+//Q=2*3.1416*L(t1-t2)/(log(r2/r1)/kA)
+t2=t1-Q1/(2*3.1416*L/(log(r2/r1)/kA));
+disp ("degree C",t2,"temperature between two layers =")
+
+
diff --git a/965/CH2/EX2.41/41.sci b/965/CH2/EX2.41/41.sci new file mode 100644 index 000000000..66b08869b --- /dev/null +++ b/965/CH2/EX2.41/41.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("Heat loss per hour")
+r1=120/2;// mm outer radius of pipe
+r2=r1+45;//mm radius of layer 1
+r3=r2+30;//mm radius of layer 2
+kA=0.08;// W/(m*C)
+kB=0.12;// W/(m*C)
+t3=25;// degree C
+L=30;//m length of pipe
+tsat=212.4;// degree c saturation temperature at pressure of 20 bar(from steam tables)
+t1=tsat+50;// temperature of steam
+
+Q1=2*3.146*L*(t1-t3)/((log(r2/r1))/kA+(log(r3/r2))/kB);
+Q=Q1*3600/1000;
+disp("W/m",Q,"heat transfer per hour = ")
+
+//Q1=2*3.14*L*(t1-t2)/((ln (r2/r1))/kA
+X=Q1*((log (r2/r1))/kA)/(2*3.146*L);
+t2=t1-X;
+disp ("degree C",t2,"interface temperature of lagging =")
diff --git a/965/CH2/EX2.42/42.sci b/965/CH2/EX2.42/42.sci new file mode 100644 index 000000000..b5908c9eb --- /dev/null +++ b/965/CH2/EX2.42/42.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("minimum thickness")
+r1=80/2;//mm
+k=0.2;// W/(m*C)
+L=25;//m
+t2=25;// degree C
+tsat=217.2;// degree C corresponding to 22 bar pressure
+t1=tsat;
+hfg=1868.1;// kJ/kg from steam tables
+dfi=0.99;// dryness factor of entering steam
+dfo=0.97;// dryness factor of outgoing steam
+
+Q=(dfi-dfo)*hfg;// heat loss per kg of steam passing through the pipe
+Qloss=Q*800/3600;//total heat loss through the pipe per second
+disp("W",Qloss*1000,"total heat loss through the pipe per second")
+
+//Qloss=2*3.1416*L*k*(t1-t2)/1og (r2/r1);
+X=2*3.1416*L*(t1-t2)*k
+r2=r1*exp(X/(Qloss*1000))
+t=r2-r1;
+disp("mm",t,"mimimum thickness of insulation =")
+
+
+
diff --git a/965/CH2/EX2.43/43.sci b/965/CH2/EX2.43/43.sci new file mode 100644 index 000000000..d255f7175 --- /dev/null +++ b/965/CH2/EX2.43/43.sci @@ -0,0 +1,37 @@ +clc;
+clear all;
+disp("heat loss per meter")
+r1=150/2;//mm inner radius of a steam pipe
+r2=160/2;//mm layer 1 radius of a steam pipe
+r3=r2+30;// mm layer 2 radius of steam pipe
+r4=r3+50;// mm outer radius of pipe
+t1=320;// degree C
+t4=40;// degree C
+kA=58;//W/(m*C)
+kB=0.18;//W/(m*C)
+kC=0.09;//W/(m*C)
+
+Q=2*3.1416*(t1-t4)/(log (r2/r1)/kA+log (r3/r2)/kB+log (r4/r3)/kC);
+disp("W",Q,"heat lost per meter =")
+
+//Q=2*3.1416*(t1-t2)/(log (r2/r1)/kA);
+X=2*3.1416/(log (r2/r1)/kA);
+t2=t1-Q/X;
+disp("degree C",t2,"temperature t2 =")
+
+//Q=2*3.1416*(t2-t3)/(log (r3/r2)/kB);
+X=2*3.1416/(log (r3/r2)/kB);
+t3=t2-Q/X;
+disp("degree C",t3,"temperature t3 =")
+
+hsteam=2703;//kJ/kg total heat pf steam when it is saturated at 320 degree C
+m=0.32;//kg/min
+Qsteam=m*hsteam-Q*60/1000;// kJ/min
+disp("kJ/min",Qsteam,"steam carried by steam per minute after losing heat in the pipe = ")
+
+//Qsteam=m*(hf+x*hfg)
+hf=1463;//kJ/kg
+hfg=1240;//kJ/kg
+x=((Qsteam/m)-hf)/hfg;
+disp(x,"amount of steam coming out of one meter pipe =")
+
diff --git a/965/CH2/EX2.44/44.sci b/965/CH2/EX2.44/44.sci new file mode 100644 index 000000000..476173e81 --- /dev/null +++ b/965/CH2/EX2.44/44.sci @@ -0,0 +1,9 @@ +clc;
+clear all;
+disp("Heat flow per meter")
+disp("k = a+b*T+c*T^2")
+disp("consider Hollow ring with radius r and thickness dr of a hollow cylinder.")
+disp(" heat flow across the ring per unit length is Q = -k*Ar*dT/dr = -k*2*%pi*r*dT/dr")
+disp("Q*dr/r = -2*%pi*(a+b*T+c*T^2)*dT")
+disp("integrating from inner to outer radiu2*s we get")
+disp("Q = 2*%pi*(T1-T2)*(a+b(T1+T2)/2+c*(T1^2+T1*T2+T2^2)/3)/(log(r2/r1)")
diff --git a/965/CH2/EX2.45/45.sci b/965/CH2/EX2.45/45.sci new file mode 100644 index 000000000..6e3ecb5a1 --- /dev/null +++ b/965/CH2/EX2.45/45.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+disp("heat storage rate")
+r1=0.3;//m inner radius of cylinder
+r2=0.5;//m outer radius of cylinder
+k=58;// W/(m*C)
+a=0.004;//m^2/h
+//T=800+1000*r-5000*r*r
+//gradT=1000-10000*r
+//Q=-k*A1*gradT;
+A1=2*3.1416*r1;
+gradT1=1000-10000*r1
+Q1=-k*A1*gradT1;//rate of heat flow at inside surface per unit length
+disp("W/m",Q1,"rate of heat transfer (in outward direction) =")
+
+A2=2*3.1416*r2;
+gradT2=1000-10000*r2
+Q2=-k*A2*gradT2;//rate of heat flow at outer surface per unit length
+disp("W/m",Q2,"rate of heat transfer (in outward direction) =")
+
+Q=Q1-Q2
+disp("W/m",Q,"rate of heat storage per unit length")
+
+//gradTtau=a*(1000/r-20000);
+gradTtau1=a*(1000/r1-20000);// rate of change of temperature at the inner surface
+gradTtau2=a*(1000/r2-20000);// rate of change of temperature at the outer surface
+
+disp("degree C/h",gradTtau1,"rate of change of temperature at the inner surface")
+disp("degree C/h",gradTtau2,"rate of change of temperature at the outer surface")
diff --git a/965/CH2/EX2.46/46.sci b/965/CH2/EX2.46/46.sci new file mode 100644 index 000000000..68e0ec7f1 --- /dev/null +++ b/965/CH2/EX2.46/46.sci @@ -0,0 +1,24 @@ +clc;
+clear all;
+disp("heat flow per length")
+r1=110;//mm outer radius of pipe
+r2=r1+50;//mm outer radius of insulation
+//k=0.06(1+0.0018*t);// W/(m*C)
+ti=280;// degree C
+to=50;// degree C
+
+km=0.06*(1+(0.0018/2)*(ti+to));
+km
+Q=2*3.1416*km*(ti-to)/(log (r2/r1));
+disp("W/m",Q,"heat transfer per unit length = ")
+
+// to calcuate the temperature at the mid thickness
+//Q=2*3.1416*k*(ti-tmt)/((ln (rmt/r1));
+rmt=(r1+r2)/2;
+//k=0.06(1+0.0018*(t1+tmt)/2)
+//Q=2*3.1416*0.06(1+0.0018*(t1+tmt)/2)*(ti-tmt)/((ln (rmt/r1))
+//0.0009*tmt^2+tmt-187.56
+tmt=(-1+(1+4*0.0009*187.56)^0.5)/(2*0.0009);
+disp("degree C",tmt,"The temperature at the mid thickness =")
+
+
diff --git a/965/CH2/EX2.47/47.sci b/965/CH2/EX2.47/47.sci new file mode 100644 index 000000000..3af270325 --- /dev/null +++ b/965/CH2/EX2.47/47.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("i) When better insulation inside")
+r1=30/2;//mm outer radius of pipe
+r2=r1+20;//mm outer radius of insulation1
+r3=r2+20;//mm outer radius of insulation2
+//kB=5*kA// W/(m*C)
+//t1 degree C
+//t3 degree C
+
+//Q1=2*3.1416*L*(t1-t3)/((log (r2/r1))/kA+(log (r3/r2))/(5*kA));
+//Q1=1.0662*2*3.1416*L*kA*(t1-t3)
+disp("heat transfer rate Q1=1.0662*2*3.1416*L*kA*(t1-t3) W ")
+
+disp("ii) When better insulation outside")
+
+//Q2=2*3.1416*L*(t1-t3)/((log (r2/r1))/(5*kA)+(log (r3/r2))/kA)
+//Q2=1.609*2*3.1416*L*kA*(t1-t3)
+//Q2/Q1=(1.609*2*3.1416*L*kA*(t1-t3))/(1.0662*2*3.1416*L*kA*(t1-t3))=1.509
+disp("Q2>Q1 hence putting better insulation next to the pipe decreases heat flow")
+//percent decrease in heat transfer=(Q2-Q1)/Q1=Q2/Q1-1
+A=1.509;//Q2/Q1
+disp("%",(A-1)*100,"percent decrease in heat transfer = ")
diff --git a/965/CH2/EX2.48/48.sci b/965/CH2/EX2.48/48.sci new file mode 100644 index 000000000..5bfe72381 --- /dev/null +++ b/965/CH2/EX2.48/48.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+
+disp("rate of heat loss")
+
+r1=60;//mm radius of pipe
+r2=r1+60;//mm radius of insulation1
+r3=r2+40;//mm radius of insulation2
+kA=0.24;// W/(m*C)
+kB=0.4;// W/(m*C)
+thf=65;// degree C
+tcf=20;// degree C
+hhf=60;// W/(m^2*C)
+hcf=12;// W/(m^2*C)
+L=60;//
+
+Q=2*3.1416*L*(thf-tcf)/(1/(hhf*r1*10^(-3))+(log (r2/r1))/kA+(log (r3/r2))/kB+1/(hcf*r3*10^(-3)));
+
+disp("W",Q,"rate of heat loss Q = ")
+
+
diff --git a/965/CH2/EX2.49/49.sci b/965/CH2/EX2.49/49.sci new file mode 100644 index 000000000..08c3b72ed --- /dev/null +++ b/965/CH2/EX2.49/49.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+
+disp("to find rate of heat loss per unit length")
+
+r1=1;//cm outer radius of pipe
+r2=r1+0.2;//mm outer radius of insulation1
+r3=r2+2;//mm outer radius of insulation2
+kA=46;// W/(m*C)
+kB=0.05;// W/(m*C)
+thf=200;// degree C
+tcf=30;// degree C
+hhf=10;// W/(m^2*C)
+hcf=5;// W/(m^2*C)
+disp ("Q=Ai*Ui*delT")
+//Ai=2*3.1416*r1*L
+Ai=2*3.1416*r1;//m area per unit length
+delT=(thf-tcf);
+Ui=1/(1/hhf+(r1*10^(-2)*(log (r2/r1))/kA)+(r1*10^(-2)*(log (r3/r2))/kB)+(r1/r3)/hcf);
+disp("W/(m^2*C)",Ui,"over all heat transfer coefficient Ui = ")
+Ql=Ai*delT*Ui*10^(-2);
+disp("W",Ql,"rate of heat loss per unit length Ql = ")
diff --git a/965/CH2/EX2.5/5.sci b/965/CH2/EX2.5/5.sci new file mode 100644 index 000000000..67ee2306b --- /dev/null +++ b/965/CH2/EX2.5/5.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("Heat loss rate")
+La=0.12;//m
+Lb=0.24;//m
+kA=1.7;// W/(m*C)
+kB=5.8;// W/(m*C)
+Rcont=0.0035;// C/W
+t1= 725;// degree C
+t4=110;// degree C
+RthA=La/kA;// C/W
+RthB=Lb/kB;// C/W
+Rth= RthA+Rcont+RthB;// C/W
+q= (t1-t4)/Rth;// W/m^2
+disp("W/m^2",q,"rate of heat loss per unit area of the wall is =")
+// q= (t1-t2)/RthA= (t3-t4)/RthB
+t2=t1-q*RthA;// degree C
+t3=q*RthB+t4;// degree C
+disp ("degree C",t2-t3,"the temperature drop is = ")
diff --git a/965/CH2/EX2.50/50.sci b/965/CH2/EX2.50/50.sci new file mode 100644 index 000000000..9ea452543 --- /dev/null +++ b/965/CH2/EX2.50/50.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("case 1:to find rate of heat transfer per unit length")
+r1=100/2;//mm inner radius of pipe
+r2=120/2;//mm outer radius of pipe
+kA=185;// W/(m*C) thermal conductivity of pipe material
+thf=110;// degree C
+tcf=30;// degree C
+hcf=15;// W/(m^2*C)
+
+Ql=2*3.1416*(thf-tcf)/((log(r2/r1))/kA+1000/(hcf*r2));
+
+disp("W",Ql,"rate of heat transfer per unit length Ql = ")
+
+disp("case 2:to find rate of heat transfer per unit length")
+
+r3=r2+50;//mm insulation radius
+kA=185;// W/(m*C) thermal conductivity of pipe material
+kB=0.2;// W/(m*C) thermal conductivity of insulation material
+thf=110;// degree C
+tcf=30;// degree C
+
+hcf=15;// W/(m^2*C)
+
+Ql=2*3.1416*(thf-tcf)/((log(r2/r1))/kA+(log(r3/r2))/kB+1000/(hcf*r3));
+
+disp("W",Ql,"rate of heat transfer per unit length of pipe Ql = ")
diff --git a/965/CH2/EX2.51/51.sci b/965/CH2/EX2.51/51.sci new file mode 100644 index 000000000..ffc5e83b3 --- /dev/null +++ b/965/CH2/EX2.51/51.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+disp("case 1:to find out thickness of insulation")
+r1=120/2;//mm inner radius of pipe
+r2=160/2;//mm outer radius of pipe
+kA=42;// W/(m*C) thermal conductivity of pipe material
+kB=0.8;// W/(m*C) thermal conductivity of insulation material
+thf=150;// degree C
+tcf=20;// degree C
+hcf=100;// W/(m^2*C)
+hcf=30;// W/(m^2*C)
+r=150/2;//mm mean radius
+//A=2*3.1416*r*L area for heat transfer
+//Q=2.1*2*3.1416*r*L
+//Q=2*3.1416*L*(thf-tcf)/(1000/(hhf*r1)+(log(r2/r1))/kA+(log(r3/r2))/kB+1000/(hcf*r3));
+//2.1*2*3.1416*r*L = 2*3.1416*L*(thf-tcf)/(1000/(hhf*r1)+(log(r2/r1))/kA+(log(r3/r2))/kB+1000/(hcf*r3))
+//2.1*r = (thf-tcf)/(1000/(hhf*r1)+(log(r2/r1))/kA+(log(r3/r2))/kB+1000/(hcf*r3))
+//(log(r3/r2))/kB+1/(30*r3)=0.6524
+//1.25*log(r3/r2)+1/(30*r3)=0.6524
+// By trial and error r3=0.105m= 105mm
+disp(" By trial and error, r3=0.105m= 105mm ")
+r3=105;//mm
+t=r3-r2;
+
+disp("m",t,"Thickness of insulation t =")
+
+
+
+
diff --git a/965/CH2/EX2.52/52.sci b/965/CH2/EX2.52/52.sci new file mode 100644 index 000000000..d1c40e33a --- /dev/null +++ b/965/CH2/EX2.52/52.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("case 1:Without extra layer of lagging")
+r1=160/2;//mm outer radius of pipe
+r2=r1+40;//mm outer radius of layer 1
+kA=0.8;// W/(m*C) thermal conductivity of pipe material
+ho=10;// W/(m^2*C)
+//ts= temperature of steam
+//ta=temperature of air
+L=1;//m length of pipe
+
+//Q1=2*3.1416*(ts-ta)/(1000/(ho*r2)+(log(r2/r1))/kA));
+//Q1=2*3.1416*(ts-ta)/1.34;
+disp("Without extra layer of lagging Q1 = 2*3.1416*(ts-ta)/1.34")
+
+disp("case 1:With extra layer of lagging")
+r3=r2+40;//mm outer radius of layer 2
+kB=1.2;// W/(m*C) thermal conductivity of insulation material
+ho=10;// W/(m^2*C)
+
+//Q2=2*3.1416*(ts-ta)/(1000/(ho*r3)+(log(r2/r1))/kA)+(log(r3/r2))/kB));
+//Q2=2*3.1416*(ts-ta)/1.343;
+disp("With extra layer of lagging Q2 = 2*3.1416*(ts-ta)/1.343")
+//(Q2-Q1)/Q1=0.00223
+t=0.00223*100;
+disp("%",t,"percentage decrease in heat flow due to extra addition of insulation =" )
+
diff --git a/965/CH2/EX2.53/53.sci b/965/CH2/EX2.53/53.sci new file mode 100644 index 000000000..dc8f12ec9 --- /dev/null +++ b/965/CH2/EX2.53/53.sci @@ -0,0 +1,31 @@ +clc;
+clear all;
+disp("case 1:Without extra layer of lagging")
+r1=70/2;//mm inner radius of pipe
+r2=85/2;//mm outer radius of pipe
+r3=r2+35;//mm radius of insulation layer 1
+r4=r3+25;//mm radius of insulation layer 2
+L=50;//m
+kA=45;// W/(m*C) thermal conductivity of pipe material
+kB=0.15;// W/(m*C) thermal conductivity of layer 1
+kC=0.075;// W/(m*C) thermal conductivity of layer 2
+hhf=220;// W/(m^2*C)
+hcf=6.5;// W/(m^2*C)
+ts= 350;// degree Ctemperature of steam
+ta=30;// ambient temperature
+
+Q=2*3.1416*L*(ts-ta)/(1000/(hhf*r1)+(log(r2/r1))/kA+(log(r3/r2))/kB+(log(r4/r3))/kC+1000/(hcf*r4));
+disp("W",Q,"Loss of heat")
+
+disp("To find overall heat transfer coefficients Ui,Uo")
+//Q=Uo*Ao*delT=Ui*Ai*delT
+delT=ts-ta;
+Ao=2*3.1416*r4*10^(-3)*L;//m^2
+Ai=2*3.1416*r1*10^(-3)*L;//m^2
+Ui=Q/(Ai*delT);//W/(m^2*C)
+Uo=Q/(Ao*delT);//W/(m^2*C)
+disp("W/(m^2*C)",Uo,"overall heat transfer coefficient Uo = ")
+disp("W/(m^2*C)",Ui,"overall heat transfer coefficient Ui = ")
+
+
+
diff --git a/965/CH2/EX2.54/54.sci b/965/CH2/EX2.54/54.sci new file mode 100644 index 000000000..e91304f7a --- /dev/null +++ b/965/CH2/EX2.54/54.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+
+disp("case 1:single layer of insulation")
+
+r1=90/2;//mm outer radius of pipe
+r2=r1+45;//mm outer radius of insulation 1
+kA=0.05;// W/(m*C)
+ho=8.4;// W/(m^2*C)
+RthA=(log(r2/r1))/(kA*2*3.1416);
+Rthconv=1000/(ho*r2*2*3.1416);
+Rth=RthA+Rthconv;
+disp("C/W per meter length",Rth,"total thermal resistance per meter length =")
+
+disp("case 1:Two layers of insulation")
+
+kB=0.07;// W/(m*C)
+//Rthconv=1000/(ho*r3*2*3.1416);
+//RthB=log(r3/r2))/(kB*2*3.1416)
+//Rth=RthA+Rthconv+RthB
+//Rth=2.206+2.274*(log(r3/0.09))+0.019/r3;
+//2.206+2.274*(log(r3/0.09))+0.019/r3=2*RthA
+disp("By trial and error,r3 =275 mm")
+r3=275;//mm
+t=r3-r2;
+disp("mm",t,"Thickness of insulation t =")
+
+
+
diff --git a/965/CH2/EX2.55/55.sci b/965/CH2/EX2.55/55.sci new file mode 100644 index 000000000..a577e9e36 --- /dev/null +++ b/965/CH2/EX2.55/55.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("To find area of superheater")
+r1=35/2;//mm inner radius of pipe
+r2=45/2;//mm outer radius of pipe
+kA=38.5;// W/(m*C) thermal conductivity of pipe material
+ho=82;// W/(m^2*C)
+hi=1120;// W/(m^2*C)
+to= 920;// degree C
+Cps=192;//kJ/(kg*C)
+ms=55;//kg
+tsup=480;// degree C
+tsat=324.6;// degree C
+ti=(tsup+tsat)/2;
+Q=ms*Cps*(tsup-tsat);//kJ/s
+//Q=2*3.1416*L*(to-ti)/(1000/(ho*r2)+(log(r2/r1))/k+1000/(hi*r1));
+L=(16410.24*10^(3))/5425.8
+disp("m")
+A=2*3.1416*r2*L/1000;
+disp("m^2",A,"Outer surface area of superheater = ")
+
+
+
diff --git a/965/CH2/EX2.56/56.sci b/965/CH2/EX2.56/56.sci new file mode 100644 index 000000000..8edbdbb5b --- /dev/null +++ b/965/CH2/EX2.56/56.sci @@ -0,0 +1,15 @@ +clc;
+clear all;
+disp("Heat loss rate")
+r1=0.250/2;// mm
+r2=0.500/2;// mm
+e=0.06;//m
+L=10;//m
+k=0.48;// W/(m*C)
+t1=280;// degree C
+t2=50;// degree C
+rp=((r1+r2)^2-e*e)^0.5;
+rm=((r2-r1)^2-e*e)^0.5;
+Rth=(1/(2*3.1416*k*L))*log((rp+rm)/(rp-rm))
+Q=(t1-t2)/Rth;
+disp("W",Q," Heat loss Q =")
diff --git a/965/CH2/EX2.57/57.sci b/965/CH2/EX2.57/57.sci new file mode 100644 index 000000000..a35109dfa --- /dev/null +++ b/965/CH2/EX2.57/57.sci @@ -0,0 +1,24 @@ +clc;
+clear all;
+disp("maximum temperature calculation")
+r1=25/2;//mm
+r2=17;//mm
+kA=0.058;// W/(m*C)
+kB=0.42;// W/(m*C)
+ho=20.5;//W/(m^2*C)
+tsurr=15;// degree C
+r3=1000*kB/ho;
+disp("mm",(r3-r2)," thickness of plastic insulation =")
+
+I=950;//A current flow
+R=22*10^(-6);// ohm/m
+L=1;//m
+Q=(I^2)*R;
+Rth= (log(r2/r1))/(2*3.1416*kA*L)+(log(r3/r2))/(2*3.1416*kB*L)+1000/(2*3.1416*r3*L*ho);// C/W
+//(t1-tsurr)/Rth=Q
+t1=Q*Rth+tsurr;
+disp("degree C",t1,"Temperature of copper rod t1 = ")
+RthA=(log(r2/r1))/(2*3.1416*kA*L);
+t2=t1-Q*RthA;// degree C
+disp("degree C",t2," Maximum temperature in plastic layer t2 = ")
+
diff --git a/965/CH2/EX2.58/58.sci b/965/CH2/EX2.58/58.sci new file mode 100644 index 000000000..612dd38d7 --- /dev/null +++ b/965/CH2/EX2.58/58.sci @@ -0,0 +1,11 @@ +clc;
+clear all;
+disp("To find heat flow rate")
+x1=50/1000;//m
+x2=250/1000;//m
+t1=400;// degree C
+t2=200;// degree C
+c=0.22;
+k=3.6 ;// W/(m*C)
+Q=3.1416*c*c*k*(t1-t2)/(4*(1/x1-1/x2));
+disp("W",Q," Heat flow rate = ")
diff --git a/965/CH2/EX2.59/59.sci b/965/CH2/EX2.59/59.sci new file mode 100644 index 000000000..e64628d88 --- /dev/null +++ b/965/CH2/EX2.59/59.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("Midpoint temperature calculation")
+r1=50/(2*1000);//m
+r2=25/(2*1000);//m
+t1=227;// degree C
+t2=27;// degree C
+k=40;// W/(m*C)
+L=0.2;//m
+Q=k*3.1416*r1*r2*(t1-t2)/L;
+disp("W",Q," Heat flow rate = ")
+disp("Temperature at the midpoint of the rod")
+//Q=3.1416*(r1+r2)*r2*k*(t-t2)/L
+t=t2+Q*L/(3.1416*(r1+r2)*r2*k);
+disp("degree C",t,"Temperature at the midpoint of the rod t =")
+
diff --git a/965/CH2/EX2.6/6.sci b/965/CH2/EX2.6/6.sci new file mode 100644 index 000000000..17b978d1a --- /dev/null +++ b/965/CH2/EX2.6/6.sci @@ -0,0 +1,15 @@ +clc;
+clear all;
+disp("Thickness of insulation")
+La=1;//m
+Lb=0.04;//m
+kA=0.7;// W/(m*C)
+kB=0.48;//W/(m*C)
+kC=0.065;//W/(m*C)
+//Q1 = A(delT)/(La/kA+Lb/kB+)=A(delT)/(0.1/0.7+0.04/0.48)
+//Q2 = A(delT)/(La/kA+Lb/kB+Lc/kC)=A(delT)/(0.1/0.7+0.04/0.48+x/0.065)
+//Q2=(1-0.8)Q1
+//A(delT)/(0.1/0.7+0.04/0.48+x/0.065)=0.2*A(delT)/(0.1/0.7+0.04/0.48)
+//0.1/0.7+0.04/0.48+x/0.065 =(0.1/0.7+0.04/0.48)/0.2
+x=(0.2261/0.2-0.2261)/15.385;//m
+disp ("mm",x*1000,"thickness of the rock wool insulation should be = ")
diff --git a/965/CH2/EX2.61/61.sci b/965/CH2/EX2.61/61.sci new file mode 100644 index 000000000..e12264ede --- /dev/null +++ b/965/CH2/EX2.61/61.sci @@ -0,0 +1,9 @@ +clc;
+clear all;
+disp("Heat leakage rate")
+r2=1.4/2;//m
+r1=r2-90/1000;//m
+delT=220;//degree C
+k=0.083;// W/(m*C)
+Q=4*3.1416*k*r1*r2*delT/(r2-r1);
+disp("W",Q,"Rate of heat leakage Q =")
diff --git a/965/CH2/EX2.62/62.sci b/965/CH2/EX2.62/62.sci new file mode 100644 index 000000000..244c95c07 --- /dev/null +++ b/965/CH2/EX2.62/62.sci @@ -0,0 +1,14 @@ +clc;
+clear all;
+disp("Rate of boiling")
+r1=.5/2;//m
+r2=r1+25/1000;//m
+t1=-196;//degree C
+t2=27;//degree C
+k=0.0017;// W/(m*C)
+ho=20;// W/(m^2*C)
+Q=4*3.1416*(t1-t2)/((r2-r1)/(k*r1*r2)+1/(ho*r2*r2));
+disp("W",-1*Q,"Rate of heat in Q =")
+hfg=2*10^5;
+mN2=(-1*Q*3600)/hfg;
+disp("kg/h",mN2,"Rate of N2 boil off mN2 =")
diff --git a/965/CH2/EX2.63/63.sci b/965/CH2/EX2.63/63.sci new file mode 100644 index 000000000..44cf1a723 --- /dev/null +++ b/965/CH2/EX2.63/63.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("Heat transfer rate")
+r1=2/2;//m
+r2=r1+2/100;//m
+r3=r2+5/1000;//m
+t1=300;//degree C
+t2=50;//degree C
+kA=58;// W/(m*C)
+kB=0.116;// W/(m*C)
+Rfilm=0.0023;// K/W
+RthA=(r2-r1)/(4*3.1416*kA*r1*r2)
+RthB=(r3-r2)/(4*3.1416*kB*r3*r2)
+Q=(t1-t2)/(RthA+RthB+Rfilm);
+disp("kW",Q/1000,"Rate of heat in Q =")
+
diff --git a/965/CH2/EX2.64/64.sci b/965/CH2/EX2.64/64.sci new file mode 100644 index 000000000..44cf1a723 --- /dev/null +++ b/965/CH2/EX2.64/64.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("Heat transfer rate")
+r1=2/2;//m
+r2=r1+2/100;//m
+r3=r2+5/1000;//m
+t1=300;//degree C
+t2=50;//degree C
+kA=58;// W/(m*C)
+kB=0.116;// W/(m*C)
+Rfilm=0.0023;// K/W
+RthA=(r2-r1)/(4*3.1416*kA*r1*r2)
+RthB=(r3-r2)/(4*3.1416*kB*r3*r2)
+Q=(t1-t2)/(RthA+RthB+Rfilm);
+disp("kW",Q/1000,"Rate of heat in Q =")
+
diff --git a/965/CH2/EX2.65/65.sci b/965/CH2/EX2.65/65.sci new file mode 100644 index 000000000..1245f5c42 --- /dev/null +++ b/965/CH2/EX2.65/65.sci @@ -0,0 +1,10 @@ +clc;
+clear all;
+disp("expression for rate")
+disp("k = k0*(1+a*t+b*t^2)")
+disp("considering steady state equation through hollow sphere r= r and thickness dr/dt, ")
+disp("Q = -k*A*dt/dr = -k*4*%pi*r^2*dt/dr =-k0*(1+a*t+b*t^2)*4*%pi*r^2*dt/dr")
+disp("thus, Q/4%pi * dr/r^2=-k0*(1+a*t+b*t^2)*dt ")
+disp("integrating the above equation in range r1 to r2 and t1 to t2 respectively, we get")
+disp("Q = (4*pi*r1*r2/(r1-r2))*k0*(t1-t2)*(1+a(t1+t2)/2)+b*(t1^2+t2^2+t2*t2)/3)")
+
diff --git a/965/CH2/EX2.66/66.sci b/965/CH2/EX2.66/66.sci new file mode 100644 index 000000000..e49770c17 --- /dev/null +++ b/965/CH2/EX2.66/66.sci @@ -0,0 +1,11 @@ +clc;
+clear all;
+disp("Heat transfer rate")
+disp("k=k1+(k2-k1)*(t-t1)/(t2-t1)")
+disp("A=4*%pi*r^2")
+disp("Q=-k*4*%pi*r^2*dt/dr")
+disp("Q=-(k1+(k2-k1)*(t-t1)/(t2-t1))*4*%pi*r^2*dt/dr")
+disp("Q*dr/r^2 =-(k1+(k2-k1)*(t-t1)/(t2-t1))*4*%pi*dt ")
+disp("By integrating both sides in the limits r1 to r2 and t1 to t2, we get,")
+disp("Q = 4*%pi*r1*r2*(k1+k2)*(t1-t2)/(2*(r2-r1))")
+
diff --git a/965/CH2/EX2.67/67.sci b/965/CH2/EX2.67/67.sci new file mode 100644 index 000000000..a1fe6024f --- /dev/null +++ b/965/CH2/EX2.67/67.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("/minimum nusselt number")
+disp("Heat flow byconduction through sphere is given by Q = (t1-t2)/((R1-R2)/4*%pi*k*R1*R2)= (t1-t2)/Rth cond")
+disp("Heat flow by convection at R2 to air is given by (t1-t2)/(1/4*%pi*h*R2^2)= (t1-t2)/Rth conv")
+disp("Rth cond = 1/(4*%pi*k)*(1/R1-1/R2)")
+disp("on neglecting motion of fluid, heat transfer will be conduction through small sphere and resistance of this shell to heat flow will be ")
+disp("Rthcond = 1/(4*%pi*r*k")
+disp("Q = (t2-ta)/(1/(4*%pi*r*k) - (1)")
+disp("Heat flow can also be given by introducing h as")
+disp("Q = (t2-ta)/(1/4*%pi*h*r^2 - (2)")
+disp("Equating (1) and (2) we get")
+disp("(t2-ta)/(1/(4*%pi*r*k)=(t2-ta)/(1/4*%pi*h*r^2")
+disp("Thus, h = k/r = 2*k/d")
+disp("Hence hd/k =2")
+disp("Thus Nu = 2")
+
diff --git a/965/CH2/EX2.69/69.sci b/965/CH2/EX2.69/69.sci new file mode 100644 index 000000000..03fbe5f6b --- /dev/null +++ b/965/CH2/EX2.69/69.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("Thermal conductivity of insulation")
+r1=1.5/2;//m
+r2=r1+0.1;//m
+Lcyl=8-1.5;//m
+m=10.8;//kg/h
+hv=214;//kJ/kg
+Qboil=m*hv;//kJ/h
+Qcyl=Qboil/(1+(2*r1*r2*log(r2/r1))/(Lcyl*(r2-r1)));
+disp("kJ/h",Qcyl,"Rate of heat in Q =")
+Qcyl=Qcyl/3.6;
+disp("J/s",Qcyl,"Rate of heat in Q =")
+ti=-183;//degree C
+to=27;//degree C
+delT=to-ti;
+k=Qcyl*(log(r2/r1))/(delT*2*3.1416*Lcyl);// W/(m*C)
+disp("W/(m*K)",k,"Thermal conductivity of insulation =")
+
+
+
diff --git a/965/CH2/EX2.7/7.sci b/965/CH2/EX2.7/7.sci new file mode 100644 index 000000000..9347bc9a4 --- /dev/null +++ b/965/CH2/EX2.7/7.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("Thickness of insulation")
+delT=1150-40;// degree C
+kA=1.52 ;//W/(m*C)
+kB= 0.138;//W/(m*C)
+kC=45;// W/(m*C)
+kD= 0.138;//W/(m*C)
+q= 400;//W/m^2
+// q = Q/A = delT/(La/kA+Lb/kB+Lc/kC+Ld/kD)
+//400 = 1110/(0.2/1.52+x/0.138+0.006/45+0.1/0.138)
+//0.8563+7.2*x = 1110/400=2.775
+x=(2.775-0.8563)/7.2
+disp ("mm",x*1000,"thickness of insulation brick is= ")
+//q=400=(tSO-40)/(Ld/kD)
+//400=(tSO-40)/(0.1/0.138)
+tSO=400/1.38+40;// degree C
+disp ("degree C",tSO,"temperature of outer surface of steel plate is = ")
diff --git a/965/CH2/EX2.70/70.sci b/965/CH2/EX2.70/70.sci new file mode 100644 index 000000000..703d35167 --- /dev/null +++ b/965/CH2/EX2.70/70.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("Radius of insulation")
+k=0.172;// W/(m*C)
+t1=475;//degree C
+t2=300;//degree C
+r1=60/2;//mm
+ho=2.8;// W/(m^2*K)
+rc=1000*k/ho;//mm
+Rthcd=(log(rc/r1))/k;
+Rthcv=1000/(ho*rc);
+disp("mm",rc,"critical radius of insulation =")
+Qwi=2*3.1416*(t1-t2)/(Rthcd+Rthcv);
+disp("W/m",Qwi,"with insulation Qwi =")
+
+Qwoi=2*3.1416*r1*ho*(t1-t2)/1000;
+disp("W/m",Qwoi,"with insulation Qwoi =")
+
diff --git a/965/CH2/EX2.71/71.sci b/965/CH2/EX2.71/71.sci new file mode 100644 index 000000000..846fe0ce6 --- /dev/null +++ b/965/CH2/EX2.71/71.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("Critical radius of insulation")
+k=0.155;// W/(m*C)
+t1=65;//degree C
+tair=20;//degree C
+r1=10/2;//mm
+ho=8.5;// W/(m^2*K)
+rc=1000*k/ho;//mm
+t=rc-r1;
+disp("mm",rc,"critical radius of insulation =")
+disp("mm",t,"thickness upto which rubber insulation is effective in heat dissipation t =")
+Rthcd=(log(rc/r1))/k
+Rthcv=1000/(ho*rc)
+Ql=2*3.1416*(t1-tair)/(Rthcd+Rthcv);
+disp("W/m",Ql,"with insulation Ql=")
diff --git a/965/CH2/EX2.72/72.sci b/965/CH2/EX2.72/72.sci new file mode 100644 index 000000000..07e63fedb --- /dev/null +++ b/965/CH2/EX2.72/72.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("heat flow through wire")
+k=0.12;// W/(m*C)
+r1=2/2;//mm
+r2=r1+0.8;//mm
+ho=35;// W/(m^2*K)
+rc=1000*k/ho;//mm
+disp("mm",rc,"critical radius of insulation =")
+
+disp("i) heat flow through an insulated wire")
+Rthcd=(log(r2/r1))/k;
+Rthcv=1000/(ho*r2);
+Rth12=Rthcd+Rthcv;
+//Q12=2*pi*L*(t1-tair)/Rth12;
+
+Rthcd=(log(rc/r1))/k;
+Rthcv=1000/(ho*rc);
+Rth1c=Rthcd+Rthcv;
+//Q1c=2*pi*L*(t1-tair)/Rth1c;
+//(Q1c-Q12)/Q12*100
+change=(1/Rth1c-1/Rth12)*100/(1/Rth12)
+disp("%")
diff --git a/965/CH2/EX2.73/73.sci b/965/CH2/EX2.73/73.sci new file mode 100644 index 000000000..38f1d621d --- /dev/null +++ b/965/CH2/EX2.73/73.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("increase in heat dissipation")
+k=0.174;// W/(m*C)
+r1=6.5/2;//mm
+ho=8.722;// W/(m^2*K)
+rc=1000*k/ho;//mm
+L=1;//m
+t1=60;// degree C
+tair=20;// degree C
+disp("mm",rc,"critical radius of insulation =")
+t=rc-r1;
+disp("mm",t,"minimum insulation of thickness t = ")
+
+disp("i) without insulation ")
+Rthcv=1000/(ho*r1);
+Q1=2*3.1416*L*(t1-tair)/Rthcv;
+disp("W/m",Q1," heat flow without insulation Q1 =")
+Rthcd=(log(rc/r1))/k;
+Rthcv=1000/(ho*rc);
+Rth2=Rthcd+Rthcv;
+Q2=2*3.1416*L*(t1-tair)/Rth2;
+disp("W/m",Q2," heat flow with insulation Q2 =")
+change=(Q2-Q1)*100/Q1;
+disp("%",change,"Percent increase in heat dissipation =")
diff --git a/965/CH2/EX2.74/74.sci b/965/CH2/EX2.74/74.sci new file mode 100644 index 000000000..152142e9e --- /dev/null +++ b/965/CH2/EX2.74/74.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("critical radius of insulation")
+kins=0.3;// W/(m*C)
+kcork=0.038;// W/(m*C)
+
+ro=30/2;//mm
+ho=12;// W/(m^2*K)
+rc=1000*kins/ho;//mm
+disp("mm",rc,"critical radius of insulation =")
+kins=ro*ho;
+disp("W/(m*C)",kins,"for insulation to be effective kins <=")
+
+L=1;//m
+
+//(log(rci/ro))/0.038+1/(12*rci)=25.25
+rci=36;//mm
+disp("By trial and error rci = 36 mm")
+disp("mm",rci-ro,"Thickness of cork insulation =")
diff --git a/965/CH2/EX2.75/75.sci b/965/CH2/EX2.75/75.sci new file mode 100644 index 000000000..928d67ae1 --- /dev/null +++ b/965/CH2/EX2.75/75.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("Thickness of insulation")
+r1=8/2;//mm
+k=0.18;// W/(m*C)
+ho=12.5;// W/(m^2*C)
+rc=1000*k/ho;//mm
+r2=rc;//mm
+t=r2-r1;//mm
+L=1;//m
+disp("mm",t,"Thickness of insulation = ")
+
+t1=45;// degree C
+t2=20;// degree C
+delT=t1-t2;
+A=2*3.1416*L*r1/1000;
+Q1=ho*A*delT;
+disp("W/m",Q1,"heat flow per unit length (without insulation) = ")
+
+//Q2=2*3.1416*L*(delT)/(1/(ho*r2)+(log(r2/r1))/k);
+//Q2=0.495*(t2-20)
+Q2=Q1;
+t2=Q2/.495+20;
+disp("degree C",t2," surface temperature of insulated cable t2 = ")
+
diff --git a/965/CH2/EX2.76/76.sci b/965/CH2/EX2.76/76.sci new file mode 100644 index 000000000..82838e44d --- /dev/null +++ b/965/CH2/EX2.76/76.sci @@ -0,0 +1,32 @@ +clc;
+clear all;
+disp("temperature at interfaces")
+L=0.16;//m thickness of slab
+qg=1.2*10^(6);// W/m^3
+k=180;// W/(m*C)
+t1=120;// degree C
+t2=t1;
+tw=t1;
+A=1;//m^2
+
+x=L/2;
+tmp=(qg/(2*k))*(L-x)*x+tw;
+Qmp=qg*A*x;
+gradTmp=-Qmp/(A*k);
+disp("degree C",tmp,"temperature at mid plane tmp = ")
+disp("W/m^2",Qmp,"heat flow rate mid plane Qmp = ")
+disp("C/m",gradTmp,"temperature gradient at the mid plane = ")
+
+x=L/4;
+t14=qg*(L-x)*x/(2*k)+tw;
+Q14=qg*A*x;
+gradT14=-Q14/(A*k);
+disp("degree C",t14,"temperature at x=L/4 = ")
+disp("W/m^2",Q14,"heat flow rate at x=L/4 Qmp = ")
+disp("C/m",gradT14,"temperature gradient at x=L/4 = ")
+
+x=3*L/4;
+t34=qg*(L-x)*x/(2*k)+tw;
+disp("degree C",t34,"temperature at x=3L/4 = ")
+
+
diff --git a/965/CH2/EX2.77/77.sci b/965/CH2/EX2.77/77.sci new file mode 100644 index 000000000..c04f8eed9 --- /dev/null +++ b/965/CH2/EX2.77/77.sci @@ -0,0 +1,12 @@ +clc;
+clear all;
+disp("Microwave heating capacity")
+L=25/1000;//m thickness of slab
+k=1;// W/(m*C)
+tmax=100;// degree C
+ta=30;
+h=20;//W/(m^2*C)
+
+//tmax=qg*(L/(2*h)+L*L/(8*k))+ta
+qg=(tmax-ta)/(L/(2*h)+L*L/(8*k));// W/m^3
+disp("kW/m^3",qg/1000,"Microwave heating capacity = ")
diff --git a/965/CH2/EX2.78/78.sci b/965/CH2/EX2.78/78.sci new file mode 100644 index 000000000..47dae472c --- /dev/null +++ b/965/CH2/EX2.78/78.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("Heat transfer coefficient")
+L=2/100;//m thickness of slab
+qg=7*10^(6);// W/m^3
+k=26;// W/(m*C)
+tmax=180;// degree C
+ta=30;//degree C
+
+//tmax=qg*(L/(2*h)+L*L/(8*k))+ta
+delT=tmax-ta;
+X=delT/qg;
+Y=X-L*L/(8*k);
+Z=L/(2*Y);
+h=Z;
+disp("W/(m^2*C)",h,"heat transfer coefficient h = ")
diff --git a/965/CH2/EX2.79/79.sci b/965/CH2/EX2.79/79.sci new file mode 100644 index 000000000..420c2fb3e --- /dev/null +++ b/965/CH2/EX2.79/79.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("heat flow rate")
+L=25/1000;//m
+qg=30*10^(6);// W/m^3
+k=48;// W/(m*C)
+tw1=180;// degree C
+tw2=120;//degree C
+
+//t=180+5412.5*x-312500*x*x
+// gradT=5412.5-2*312500*x
+x=5412.5/(2*312500);
+Tmax=180+5412.5*x-312500*x*x;// degree C
+disp ("degree C",Tmax,"Tmax=","mm",x*1000,"x =","value and position of maximum temperature are ")
+x=0;// at the left face
+gradT=5412.5-2*312500*x;
+Q=-k*A*gradT;
+disp("W/(m^2)",Q,"heat flow at the left face Q = ")
+x=L;// at the right face
+gradT=5412.5-2*312500*x;
+Q=k*A*gradT;
+disp("W/(m^2)",Q,"heat flow at the right face Q = ")
diff --git a/965/CH2/EX2.8/8.sci b/965/CH2/EX2.8/8.sci new file mode 100644 index 000000000..77ba284bc --- /dev/null +++ b/965/CH2/EX2.8/8.sci @@ -0,0 +1,28 @@ +clc;
+clear all;
+disp("temperature between layers")
+La=0.22;//m
+Lb=0.15;//m
+Lc=0.05;//m
+Ld=0.003;//m
+kA=4;// kJ/(mh*C)
+kB=2.8;// kJ/(mh*C)
+kC=0.24;// kJ/(mh*C)
+kD=240;// kJ/(mh*C)
+t1= 1500;// degree C
+t5=90;// degree C
+RthA=La/kA;//(m^2)*h*C/kJ
+RthB=Lb/kB;// (m^2)*h*C/kJ
+RthC=Lc/kC;// (m^2)*h*C/kJ
+RthD=Ld/kD;// (m^2)*h*C/kJ
+Rtotal= RthA+RthB+RthC+RthD;// (m^2)*h*C/kJ
+disp ("(m^2)*h*C/kJ",Rtotal,"total thermal resistance is = ")
+q= (t1-t5)/Rtotal;// kJ/(h*m^2)
+disp("kJ/(h*m^2)",q,"rate of heat loss per unit area of the wall is =")
+// q= (t1-t2)/RthA= (t3-t4)/RthB
+t4=t5+q*RthD;// degree C
+disp ("degree C",t4,"the temperature t4 is = ")
+t3=t4+q*RthC;// degree C
+disp ("degree C",t3,"the temperature t3 is = ")
+t2=t3+q*RthB;// degree C
+disp ("degree C",t2,"the temperature t2 is = ")
diff --git a/965/CH2/EX2.80/80.sci b/965/CH2/EX2.80/80.sci new file mode 100644 index 000000000..bc7bb8688 --- /dev/null +++ b/965/CH2/EX2.80/80.sci @@ -0,0 +1,11 @@ +clc;
+clear all;
+disp("Maximum temperature")
+L=1;//m thickness of slab
+qg=500;// W/m^3
+k=25;// W/(m*C)
+t1=350;// degree C
+// Maximum temperature at x =0
+x=0;
+Tmax=qg*L*L(1-(0.5*x)^2)/(2*k)+t1;// degree C
+disp("degree C",Tmax,"Maximum temperature at x = 0, Tmax =")
diff --git a/965/CH2/EX2.9/9.sci b/965/CH2/EX2.9/9.sci new file mode 100644 index 000000000..2796e77ee --- /dev/null +++ b/965/CH2/EX2.9/9.sci @@ -0,0 +1,15 @@ +clc;
+clear all;
+disp("Heat transfer rate")
+L=0.6;//m
+r=.12;//m
+theta=3.14/3;// adian=(60)degree
+t1=125;// degree C
+t2=25;// degree C
+k0=115;// W/(m*C)
+B=10^(-4);
+tm=(t1+t2)/2;
+km=k0*(1-B*tm);
+A=(r^2)*theta/2;
+Q=(-1)*km*A*(t2-t1)/L;
+disp ("W",Q,"rate of heat transfer is = ")
diff --git a/965/CH3/EX3.1/1.sci b/965/CH3/EX3.1/1.sci new file mode 100644 index 000000000..5518f928a --- /dev/null +++ b/965/CH3/EX3.1/1.sci @@ -0,0 +1,40 @@ +clc;
+clear all;
+disp("steady state temperature distribution")
+disp("Let th = t-ta")
+disp("the controllign differential equation for the given problem is given by")
+disp("d2th/dx2+d2th/dy2 =0------(1)")
+disp("the boundary conditions are :")
+disp("i) at x = infinity, th =0")
+disp("ii) at x = 0, th =th0")
+disp("iii) at y =L, th =0")
+disp("iv) at y = 0, th =0")
+disp("The solution of eq. 1 is th = X(x)Y(y) ------ (2)")
+disp("substituting the solution in controlling equation, we get ")
+disp("1/X*d2X/dx2 =-1/Y*d2Y/dy2 = + or - lambda^2")
+disp("The required equations are :")
+disp("d2X^2/dx2-lambda^2*X =0 ------(iii)")
+disp("d2Y^2/dy2+lambda^2*Y =0 ------(iv)")
+disp("the solutions of eqns are :")
+disp("X = A*exp(lambda*x)+B*exp(-lambda*x)")
+disp("Y = C*cos(lambda*y)+D*sin(lambda*y)")
+disp("th = (A*exp(lambda*x)+B*exp(-lambda*x))*(C*cos(lambda*y)+D*sin(lambda*y))")
+disp(" from boundary condition i), we have ")
+disp("0 = (A*exp(lambda*x)+B*exp(-lambda*x))*(C*cos(lambda*y)+D*sin(lambda*y)")
+disp("A = 0 and th =B*(C*cos(lambda*y)+D*sin(lambda*y)")
+disp("from boundary condition iv), we have")
+disp("0 = C*B*exp(-lambda*x)")
+disp("hence C = 0 and equation reduces to th = B*D*sin(lambda*y)*exp(-lambda*x)")
+disp("from boundary condition iii) we get, 0 = E*exp(-lambda*x)*sin(lambda*L), where E = B*D")
+disp("since E is not 0, sin (lambda*L)=0")
+disp("lambda = 0, %pi/L,2*%pi/L.....")
+disp("lambdan = n*%pi/L, where n = 0,1,2....")
+disp("hence , th = E*exp(-lambdan*x)*sin(lambdan*y)")
+disp("from boundary eqn ii) we have ")
+disp("th = sum(En*sin(lambdan*y), 1, infinity)")
+disp("This is an expression of th0 in terms of Fourier series, where En are Fourier coefficients.")
+disp("by integrating we get")
+disp("th = 2*th0/L*(sum(((1-(-1)^n)/lambdan *exp(-lambdan*x)*sin(lambdan*y))")
+
+,
+
diff --git a/965/CH3/EX3.3/3.sci b/965/CH3/EX3.3/3.sci new file mode 100644 index 000000000..f5ec0484a --- /dev/null +++ b/965/CH3/EX3.3/3.sci @@ -0,0 +1,12 @@ +clc;
+clear all;
+disp("Heat loss calculation")
+r=0.6/2;//m
+L=1;//m
+H=1.8;//m
+k=0.51;// W/(m*C)
+tp=95;// degree C
+te=25;// degree C
+Sfc=2*3.1416*L/(log(2*H/r));
+Q=k*Sfc*(tp-te);
+disp("W",Q,"Heat loss from the pipe meter length, Q =")
diff --git a/965/CH3/EX3.4/4.sci b/965/CH3/EX3.4/4.sci new file mode 100644 index 000000000..545ca9a36 --- /dev/null +++ b/965/CH3/EX3.4/4.sci @@ -0,0 +1,14 @@ +clc;
+clear all;
+disp("Sphere Surface temperature")
+r=1.6/2;//m
+
+H=5.5;//m
+k=0.51;// W/(m*C)
+Qg=580;// W
+
+te=6;// degree C
+Sfc=4*3.1416*r/(1-r/(2*H));
+//Qg=k*Sfc*(t-te);
+t=Qg/(k*Sfc)+te;
+disp("degree C",t,"surface temperature of sphere, t =")
diff --git a/965/CH3/EX3.5/5.sci b/965/CH3/EX3.5/5.sci new file mode 100644 index 000000000..52758e6cf --- /dev/null +++ b/965/CH3/EX3.5/5.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("Heat loss/length")
+a=0.6;// m
+b=0.45;//m
+H=1.5;//m
+k=0.51;// W/(m*C)
+tp=105;// degree C
+ts=5;// degree C
+
+x=log(1+H/a);
+y=H/b;
+
+Sfc=2.756*((x^(-.59))*(y^(-.078)));
+
+Q=k*Sfc*(tp-ts);
+
+disp("W",Q,"Heat loss per meter length, Q =")
diff --git a/965/CH3/EX3.6/6.sci b/965/CH3/EX3.6/6.sci new file mode 100644 index 000000000..b95cbc9e2 --- /dev/null +++ b/965/CH3/EX3.6/6.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("heat transfer rate, temperature")
+r1=0.600/2;// m
+r2=0.18/2;//m
+D=1.8;//m
+L=90;//m
+tp1=180;// degree C
+tp2=12;// degree C
+k=0.45;// W/(m*C)
+
+Sfc=2*3.1416*L/(acosh((D^2-r1^2-r2^2)/(2*r1*r2)));
+Sfc
+Q=k*Sfc*(tp1-tp2);
+
+disp("W",Q,"Heat loss per meter length, Q =")
diff --git a/965/CH3/EX3.7/7.sci b/965/CH3/EX3.7/7.sci new file mode 100644 index 000000000..2332ec997 --- /dev/null +++ b/965/CH3/EX3.7/7.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("Heat loss calculations")
+k=1.05;// W/(m*C)
+ti=600;//degree C
+to=70;// degree C
+L=0.12;//m
+A=0.6*0.6;//m^2
+Sfcwall=A/L;
+
+D=0.6;//m
+Sfcedge=0.54*D;
+
+Sfccorner=0.15*L;
+Sfct=6*Sfcwall+12*Sfcedge+8*Sfccorner;
+
+Q=k*Sfct*(ti-to);
+
+disp("W",Q,"Heat loss through walls, Q =")
diff --git a/965/CH3/EX3.8/8.sci b/965/CH3/EX3.8/8.sci new file mode 100644 index 000000000..839c75bee --- /dev/null +++ b/965/CH3/EX3.8/8.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("Heat loss rate")
+ti=350;// degree C
+to=50;// degree C
+k=1.5;// W/(m*C)
+x=0.3;// m
+l=4.5;//m
+b=3.75;//m
+h=3;//m
+Ai=2*(l*b+l*h+b*h);//m^2
+y=4*(l+b+h);// length of edges
+Sfce=y;
+Sfcc=0.15*x;
+
+Am=Ai+Sfce*.54*x+8*Sfcc*x;
+Am
+disp("m^2")
+Q=k*Am*(ti-to)/x;
+disp("W",Q,"rate of heat loss Q =")
+
+
diff --git a/965/CH4/EX4.1/1.sci b/965/CH4/EX4.1/1.sci new file mode 100644 index 000000000..962b43411 --- /dev/null +++ b/965/CH4/EX4.1/1.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("required time calculation")
+As=2*0.5*0.5;// m^2 surface area of plate
+V=0.5*0.5*0.00625;// m^3 volume of plate
+Lc=V/As;// m characteristic length of plate
+h=90; //W/m^2/C
+k=370;//W/m.C
+rho=9000;// kg/m^3
+C=380;//J/kg.C
+t=108;// degree C
+ta= 36;// degree C
+ti=300;// degree C
+Bi=h*Lc/k;// biot number
+if (Bi< 0.1)
+disp("Bi is less than 0.1 hence lumped heat capacity method can be applied")
+disp("Temperature distribution is given by : (t-ta)/(ti-ta) = exp((-h*As*tau)/rho*V*C)")
+m=(t-ta)/(ti-ta);
+x=-h*As/(V*rho*C);
+disp("sunstituting the values we get,")
+tau = (log(m))/x;
+disp("sec",tau,"time required to attend the temperature is ")
diff --git a/965/CH4/EX4.10/10.sci b/965/CH4/EX4.10/10.sci new file mode 100644 index 000000000..ee6e65c77 --- /dev/null +++ b/965/CH4/EX4.10/10.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("temperature and time")
+R=40/2000;//m
+ti=20;// degree C
+tau=4*60;//s
+ta=100;// degree C
+k=10;// W/m.C
+rho=1200;// kg/m^3
+c=2000;// J/kg.C
+h=100;//W/m^2.C
+Lc=R/3;// for sphere
+Bi=h*Lc/k
+
+t=ta+(ti-ta)*exp(-h*3*tau/(R*rho*c))
+disp("degree C")
+ti=5;// degree C
+X=(t-ta)/(ti-ta);
+Y=-h*3/(R*rho*c)
+tau=(log (X))/Y;// sec
+disp("min",tau/60,"time taken tau =")
diff --git a/965/CH4/EX4.11/11.sci b/965/CH4/EX4.11/11.sci new file mode 100644 index 000000000..decc11189 --- /dev/null +++ b/965/CH4/EX4.11/11.sci @@ -0,0 +1,33 @@ +clc;
+clear all;
+disp("ingot time required")
+R=50/2000;//m
+L=200/1000;//m
+k=60;// W/m.C
+c=200;// J/kg.C
+rho=800;// kg/m^3
+hw=200;//W/m^2.C
+ha=20;//W/m^2.C
+ta=30;// degree C
+ti=800;// degree C
+
+Lc=R/2;
+Bi=hw*Lc/k;
+disp(Bi,"Bi =")
+t=500;// degree C
+As=2*3.1416*R*L;//m^2
+V=3.1416*R*R*L;//m^3
+X=hw*As/(rho*V*c)
+tau1=(-1/X)*log((t-ta)/(ti-ta));
+disp(tau1,"tau1 =")
+
+t=100;// degree C
+ti=500// degree C
+X=ha*As/(rho*V*c);
+tau2=(-1/X)*log((t-ta)/(ti-ta));
+disp(tau2,"tau2 =")
+
+tau=tau1+tau2;
+disp("min",tau/60,"total time, tau =")
+
+
diff --git a/965/CH4/EX4.12/12.sci b/965/CH4/EX4.12/12.sci new file mode 100644 index 000000000..e946c3a3e --- /dev/null +++ b/965/CH4/EX4.12/12.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("spherical thermocouple junction")
+h=400;//W/m^2.C
+k=20;// W/m.C
+c=400;// J/kg.C
+rho=8500;// kg/m^3
+tau=1;//second
+
+
+R=tau*h*3/(rho*c)
+disp("mm",2*R*1000,"Diameter =")
+
+Lc=R/3;
+Bi=h*Lc/k;
+disp(Bi,"Bi =")
+
+ti=25;//degree C
+t=198;//degree C
+ta=200;// degree C
+
+As=4*3.1416*R*R;//m^2
+V=4*3.1416*(R^3)/3;//m^3
+
+X=h*As/(rho*V*c);
+tau=(-1/X)*log((t-ta)/(ti-ta));
+disp("s",tau,"tau =")
diff --git a/965/CH4/EX4.13/13.sci b/965/CH4/EX4.13/13.sci new file mode 100644 index 000000000..71609efaa --- /dev/null +++ b/965/CH4/EX4.13/13.sci @@ -0,0 +1,32 @@ +clc;
+clear all;
+disp("spherical thermocouple junction")
+R=8/2000;//m
+hg=40;//W/m^2.C
+ha=10;//W/m^2.C
+k=40;// W/m.C
+c=420;// J/kg.C
+rho=8000;// kg/m^3
+
+As=4*3.1416*R*R;//m^2
+V=4*3.1416*(R^3)/3;//m^3
+
+
+tau1=rho*V*c/(hg*As);
+disp("s",tau1,"tau* =")
+
+ta=300;// degree C
+ti=40;//degree C
+tau2=10;//s
+X=-1*tau2/tau1;
+t=ta+(ti-ta)*exp(X);
+disp("degree C",t,"temperature during heating t =")
+
+tau3=20;//s
+tau4=rho*R*c/(3*ha);//s
+disp("s",tau4,"tau* =")
+ti=t;// degree C
+X=-1*tau3/tau4;
+ta=30;//degree C
+t=ta+(ti-ta)*exp(X);//degree C
+disp("degree C",t,"temperature during cooling t =")
diff --git a/965/CH4/EX4.14/14.sci b/965/CH4/EX4.14/14.sci new file mode 100644 index 000000000..92b2ea5ee --- /dev/null +++ b/965/CH4/EX4.14/14.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("cylindrical thermometer ")
+R=3/2000;//m
+h=55;//W/m^2.C
+k=8.8;// W/m.C
+a=0.0166;// m^2/h
+c=420;// J/kg.C
+L=1;//m
+
+As=2*3.1416*R*L;//m^2
+V=3.1416*(R^2);//m^3
+
+
+tau1=k*V*3600/(h*a*As);
+disp("s",tau1,"tau* =")
+disp("for temperature to reach half its final")
+//theta/thetai=0.5=exp(-tau/tau1)
+tau= -tau1*log(0.5);
+disp("s",tau,"time required to temperature to half its final value t =")
diff --git a/965/CH4/EX4.15/15.sci b/965/CH4/EX4.15/15.sci new file mode 100644 index 000000000..82ac133fc --- /dev/null +++ b/965/CH4/EX4.15/15.sci @@ -0,0 +1,34 @@ +clc;
+clear all;
+disp("copper-constantan thermometer")
+R=2.5/2000;//m
+ti=25;//degree C
+ta=215;// degree C
+t=165;// degree C
+rho=8750;// kg/m^3
+c=380;// J/kg.C
+h=145;//W/m^2.C
+kth=28;// W/m.C
+
+As=4*3.1416*R*R;//m^2
+V=4*3.1416*(R^3)/3;//m^3
+Lc=V/As;
+a=k/(rho*c);
+//Fo=a*tau/Lc^2;
+Bi=h*Lc/k;
+th=t-ta;
+tha=ti-ta;
+thm=th/tha;
+
+Fo=(-1/Bi)*log(thm);
+tau=(Fo*Lc^2)/a;
+disp("s",tau,"tau =")
+
+Fo=1/Bi;
+tau=(Fo*Lc^2)/a;
+disp("s",tau,"tau* =")
+thm=exp(-1);
+th=thm*tha;
+t=th+ta;
+
+disp("degree C",t,"temperature t =")
diff --git a/965/CH4/EX4.16/16.sci b/965/CH4/EX4.16/16.sci new file mode 100644 index 000000000..0440c8aac --- /dev/null +++ b/965/CH4/EX4.16/16.sci @@ -0,0 +1,28 @@ +clc;
+clear all;
+disp("temperation variation")
+L=60/2000;//m
+k=42.6;// W/(m.C)
+a=0.043;// m^2/h
+ti=440;// degree C
+h=235;// W/(m^ 2.C)
+ta=50;// degree C
+tau=4.3*60;//seconds
+Lc=L;// characteristic length
+Fo=a*tau/Lc^2;
+Bi=h*Lc/k;
+if Bi>1
+disp("Internal temperature gradients are not small and can not be neglected")
+end
+Bii=1/Bi;
+x=0;// midplane
+//(to-ta)/(ti-ta)=0.6
+to=0.6*(ti-ta)+ta;
+disp("Degree C",to,"Temperature at midplane Tm =")
+ x=0.015/L;
+ Bii=6.06;
+ ti=to;
+ //(to-ta)/(ti-ta)=0.97
+ to=0.97*(ti-ta)+ta;
+ disp("Degree C",to,"Temperature inside the plate 15mm from the midplane To =")
+
diff --git a/965/CH4/EX4.17/17.sci b/965/CH4/EX4.17/17.sci new file mode 100644 index 000000000..918f54b29 --- /dev/null +++ b/965/CH4/EX4.17/17.sci @@ -0,0 +1,31 @@ +clc;
+clear all;
+disp("time and temperature ")
+L=6/2000;//m
+rho=7800;// kg/m^3
+c=460;// J/(kg.C)
+k=55;// W/(kgm.C)
+ti=30;// degree C
+ta=2150;// degree C
+t=1100;// degree C
+
+Lc=L;// characteristic length
+Bi=h*Lc/k;
+if Bi>1
+disp("Internal temperature gradients are not small and can not be neglected")
+end
+Fo=a*tau/Lc^2;
+T1=(t-ta)/(ti-ta);
+//T2=(to-ta)/(ti-ta);
+//T3=(t-ta)/(to-ta);
+T3=0.93;
+T2=T1/T3;
+Bii=1/Bi;
+Fo=4.4;
+//a*tau/Lc^2
+a=k/(rho*c);
+tau=Fo*Lc*Lc/a;
+disp("sec",tau,"Tau =")
+ to=0.495*(ti-ta)+ta;
+ disp("Degree C",to,"Temperature inside To =")
+
diff --git a/965/CH4/EX4.18/18.sci b/965/CH4/EX4.18/18.sci new file mode 100644 index 000000000..2b1dbd809 --- /dev/null +++ b/965/CH4/EX4.18/18.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+disp("time and temperature")
+R=80/1000;//m
+k=17.4;// W/(m.C)
+ti=830;// degree C
+ta=40;// degree C
+t=120;// degree C
+a=0.019;// m^2/h
+h=180;// W/(m^2.C)
+
+Lc=3.1416*R*R*L/(2*3.1416*R*L);// characteristic length
+Bi=h*Lc/k;
+if Bi>1
+disp("Internal temperature gradients are not small and can not be neglected")
+end
+Bii=1/Bi;
+Fo=3.2;
+tau=3600*Fo*Lc^2/a;
+disp("sec",tau,"Tau =")
+r=R;
+Bii=1/Bi;
+T1=0.83;
+t1=T1*(t-ta)+ta;
+ts=t1;
+disp("degree C",ts,"Temperature at the surface Ts =")
+gradt=h*(ts-ta)/k;
+disp("C/m",gradt,"Temperature gradient =")
+
diff --git a/965/CH4/EX4.19/19.sci b/965/CH4/EX4.19/19.sci new file mode 100644 index 000000000..b778dcd8e --- /dev/null +++ b/965/CH4/EX4.19/19.sci @@ -0,0 +1,26 @@ +clc;
+clear all;
+disp("temperature at centre")
+R=60/1000;//m
+rho=990;// kg/m^3
+c=4170;//J/(kg.C)
+k=0.58;// W/(m.C)
+ti=25;// degree C
+ta=6;// degree C
+tau=2*3600;// seconds
+h=5.8;// W/(m^2.C)
+
+Lc=(4/3)*3.1416*R*R*R/(4*3.1416*R*R);// characteristic length
+Bi=h*Lc/k;
+if Bi>1
+disp("Internal temperature gradients are not small and can not be neglected")
+end
+Bii=1/Bi;
+Fo=k*tau/(rho*c*R^2);
+r=0;// midplane of the apple
+Bii=1/Bi;
+
+T1=0.75;
+t1=T1*(ti-ta)+ta;
+disp("degree C",t1,"Temperature Tm =")
+
diff --git a/965/CH4/EX4.2/2.sci b/965/CH4/EX4.2/2.sci new file mode 100644 index 000000000..b55742fda --- /dev/null +++ b/965/CH4/EX4.2/2.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("required time calculation")
+As=2*0.4*0.4;// m^2 surface area of plate
+V=0.4*0.4*4/1000;// m^3 volume of plate
+Lc=V/As;// m characteristic length of plate
+h=20000;//kJ/m^2.h.C
+k=370;//W/m.C
+rho=3000;// kg/m^3
+C=0.8;//kJ/kg.C
+t=-70;// degree C
+ta=-183;// degree C
+ti=200;// degree C
+Bi=h*Lc/k;// biot number
+if (Bi< 0.1)
+disp("Bi is less than 0.1 hence lumped heat capacity method can be applied")
+end
+disp("Temperature distribution is given by : (t-ta)/(ti-ta) = exp((-h*As*tau)/rho*V*C)")
+m= (t-ta)/(ti-ta);
+x=-h/(Lc*rho*C);
+tau=3600*(log(m))/x;
+disp("sec",tau,"time required to attend the temperature is ")
diff --git a/965/CH4/EX4.20/20.sci b/965/CH4/EX4.20/20.sci new file mode 100644 index 000000000..6b94fe4f1 --- /dev/null +++ b/965/CH4/EX4.20/20.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("time required")
+x=12/1000;//m
+a=1.2*10^(-5);//m^2/s
+ti=745;// degree C
+ta=20;// degree C
+t=595;// degree C
+
+
+T1=(t-ta)/(ti-ta);
+erfM=T1;
+M=0.9;// from tables
+tau=((x/M)^2)/(4*a);
+disp("seconds",tau,"Tau =")
+
+
diff --git a/965/CH4/EX4.21/21.sci b/965/CH4/EX4.21/21.sci new file mode 100644 index 000000000..8b231d397 --- /dev/null +++ b/965/CH4/EX4.21/21.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("to find Depth")
+a=2.75*10^(-3);//m^2/h
+ti=5.4;// degree C
+ta=-6;// degree C
+t=0;// degree C
+tau=9.5;// hours
+
+
+T1=(t-ta)/(ti-ta);
+erfM=T1;
+M=0.5;// from tables
+x=2*M*(a*tau)^0.5;
+disp("m",x,"x =")
+
+
+
diff --git a/965/CH4/EX4.22/22.sci b/965/CH4/EX4.22/22.sci new file mode 100644 index 000000000..b6e69e9fb --- /dev/null +++ b/965/CH4/EX4.22/22.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("Time and Temperature")
+L=60/1000;// m
+a=1.22*10^(-5);//m^2/s
+ti=30;// degree C
+ta=110;// degree C
+tau=1.5*60;// seconds
+
+taumax=L^2/(4*a*0.25);
+disp("s",taumax,"maximum time that the slab be treated asa semi infinite body taumax=")
+x=L/2;
+M=x/(2*(a*tau)^0.5);
+//erfM=0.47=T1;
+T1=0.47;
+t=ta+T1*(ti-ta);
+disp("degree C",t,"temperature at the centre of slab T =")
+
+
diff --git a/965/CH4/EX4.23/23.sci b/965/CH4/EX4.23/23.sci new file mode 100644 index 000000000..ad029ad64 --- /dev/null +++ b/965/CH4/EX4.23/23.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("Temperature & heat rate")
+x=80/1000;// m
+a=1.6*10^(-3);//m^2/h
+ti=25;// degree C
+ta=340;// degree C
+k=0.94;// W/(m.C)
+tau=8;//hours
+
+M=x/(2*(a*tau)^0.5);
+M
+//erfM=0.37=T1;
+T1=0.37;
+
+t=ta+T1*(ti-ta);
+disp("degree C",t,"temperature at the centre of slab T =")
+
+Q=k*(ti-ta)*(exp(-M*M))/(3.1416*a*tau)^0.5;
+disp("W/m^2",Q,"instantaneous heat flow rate Q =")
+ Qs=k*(ti-ta)/(3.1416*a*tau)^0.5;
+disp("W/m^2",Qs,"heat flow rate at the surface Qs =")
diff --git a/965/CH4/EX4.24/24.sci b/965/CH4/EX4.24/24.sci new file mode 100644 index 000000000..06b67e43d --- /dev/null +++ b/965/CH4/EX4.24/24.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("Time Required")
+x=0;// m
+gradT=400;// C/m
+a=0.42;//m^2/h
+ti=120;// degree C
+ta=6;// degree C
+k=0.94;// W/(m.C)
+tau=8;//hours
+
+//Qs=k*gradT=k*(ti-ta)/(3.1416*a*tau)^0.5;
+//gradT=(ti-ta)/(3.1416*a*tau)^0.5
+tau=(((ti-ta)/gradT)^2)/(3.1416*a);
+disp("seconds",tau*3600,"time required Tau =")
+
+
diff --git a/965/CH4/EX4.25/25.sci b/965/CH4/EX4.25/25.sci new file mode 100644 index 000000000..0fef49ef0 --- /dev/null +++ b/965/CH4/EX4.25/25.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+
+disp("Maximum temperature rise")
+a=1.25*10^(-5);//m^2/s
+k=54;// W/(m.C)
+A=4*360*10^(-4);//m^2
+m=1600;//kg
+v=90;// km/h
+tau=9;//seconds
+
+KE=0.5*m*v*v*(1000/3600)^2;
+Q=KE/tau;
+Qs=Q;
+disp("W",Q,"heat flow rate at surface Qs =")
+//Qs=-k*(ti-ta)/(3.1416*a*tau)^0.5;
+delT=Qs*((3.1416*a*tau)^0.5)/(k*A);
+
+disp("degree C",delT,"temperature rise ta-ti =")
+
+
diff --git a/965/CH4/EX4.26/26.sci b/965/CH4/EX4.26/26.sci new file mode 100644 index 000000000..67e503075 --- /dev/null +++ b/965/CH4/EX4.26/26.sci @@ -0,0 +1,24 @@ +clc;
+clear all;
+disp("Time and Temperature")
+R=300/1000;//m
+a=1.12*10^(-4);//m^2/s
+ti=20;//degree C
+ta=480;// degree C
+t=350;// degree C
+tau=3*60;//seconds
+
+M=a*tau/R^2;
+erfM=0.32;
+T1=erfM;
+
+t=ta+T1*(ti-ta);
+disp("degree C",t,"temperature at the centre of surface T=")
+t=350;//
+T1=(t-ta)/(ti-ta);
+M=0.23;
+tau=M*(R^2)/a;
+
+disp("sec",tau,"time required Tau =")
+
+
diff --git a/965/CH4/EX4.27/27.sci b/965/CH4/EX4.27/27.sci new file mode 100644 index 000000000..f599e5dde --- /dev/null +++ b/965/CH4/EX4.27/27.sci @@ -0,0 +1,15 @@ +clc;
+clear all;
+disp("The Time lag")
+x=300/1000;//m
+rho=1600;// kg/m^3
+k=0.65;//W/(m.C)
+c=440;// J/(kg.C)
+n=1/24;// h^-1
+n
+a=k*3600/(rho*c);
+a
+deltau = (x/2)*(1/(3.1416*a*n)^(0.5));
+
+disp("h",deltau,"time lag =")
+
diff --git a/965/CH4/EX4.28/28.sci b/965/CH4/EX4.28/28.sci new file mode 100644 index 000000000..c3a448aef --- /dev/null +++ b/965/CH4/EX4.28/28.sci @@ -0,0 +1,9 @@ +clc;
+clear all;
+disp("Depth and Temperature")
+a=0.044;//m^2/h
+n=1400*60;// h^-1
+theta=2/100;
+
+x=-((a/(3.1416*n))^0.5)*log (theta);
+disp("mm",x*1000,"depth x =")
diff --git a/965/CH4/EX4.29/29.sci b/965/CH4/EX4.29/29.sci new file mode 100644 index 000000000..c8404ab54 --- /dev/null +++ b/965/CH4/EX4.29/29.sci @@ -0,0 +1,35 @@ +clc;
+clear all;
+disp("Heat rate & energy")
+A=5;//m^2
+k=1.2;// W/(m.C)
+a=1.77*10^(-3);//m^2/h
+//t =(120-100*x+24*x^2+40*x^3-30*x^4
+//gradT=-100+48*x+120*x*x-120*x^3;
+//d2T=48+240*x-360*x*x
+
+x=0;
+t=120-100*x+24*x^2+40*x^3-30*x^4;
+gradT=-100+48*x+120*x*x-120*x^3;
+Qin=-k*A*gradT;
+disp("W",Qin," heat entering the slab Qin =")
+x=0.5;
+gradT=-100+48*x+120*x*x-120*x^3;
+Qout=-k*A*gradT;
+disp("W",Qout," heat leaving the slab Qout =")
+
+Qs=Qin-Qout;
+disp("W",Qs," heat stored in the unit time Qs =")
+
+x=0;
+d2T=48+240*x-360*x*x;
+Tt=a*d2T;
+disp("C/h",Tt,"rate of temperature change at inlet =")
+
+x=0.5;
+d2T=48+240*x-360*x*x;
+Tt=a*d2T;
+disp("C/h",Tt,"rate of temperature change at outlet =")
+//d3T =240-720x =0
+x=240/720;//m
+disp("m",x,"point where rate of heating/cooling is maximum x =")
diff --git a/965/CH4/EX4.3/3.sci b/965/CH4/EX4.3/3.sci new file mode 100644 index 000000000..280eb7335 --- /dev/null +++ b/965/CH4/EX4.3/3.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("required temperature calculation")
+D=0.1;//m dimeter
+R=D/2;//m radius
+As=4*%pi*(R^2);// m^2 surface area of sphere
+V=4*%pi*(R^3)/3;// m^3 volume of sphere
+Lc=V/As;// m characteristic length of sphere
+h=200; //W/m^2/C
+k=386;//W/m.C
+rho=8954;// kg/m^3
+C=383;//J/kg.C
+ta=50;// degree C
+ti=250;// degree C
+tau = 5*60;//sec
+Bi=h*Lc/k;// biot number
+if (Bi< 0.1)
+disp("Bi is less than 0.1 hence lumped heat capacity method can be applied")
+disp("Temperature distribution is given by : (t-ta)/(ti-ta) = exp((-h*As*tau)/(rho*V*C))")
+t = ta+(ti-ta)*exp((-h*As*tau)/(rho*V*C));
+disp("degree C",t,"the temperature attained is ")
diff --git a/965/CH4/EX4.30/30.sci b/965/CH4/EX4.30/30.sci new file mode 100644 index 000000000..a0e36eda3 --- /dev/null +++ b/965/CH4/EX4.30/30.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("Temperautre and rate")
+R=50/1000;//m
+ti=900;// degree C
+ta=30;//degree C
+h=20;// W/(m^2.C)
+rhos=7800;//kg/m^3
+cs=460;// J/kg.C
+tau=30;//s
+k=40;//W/(m.C)
+
+
+Lc=R/3;//m
+Bi=h*Lc/k;
+As=4*3.1416*R^2;
+V=4/3*3.1416*R^3;
+X=h*As*tau/(rhos*V*cs);
+M=exp(-X);
+t=ta+(ti-ta)*M;
+disp("degree C",t," temperature of ball after 30 sec, t =")
+
+gradT=(ti-ta)*M*(-X/tau);
+disp("C/min",gradT*60," rate of cooling after 30 seconds =")
+
diff --git a/965/CH4/EX4.31/31.sci b/965/CH4/EX4.31/31.sci new file mode 100644 index 000000000..5fbbc1621 --- /dev/null +++ b/965/CH4/EX4.31/31.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("Time for cooling")
+L=20/1000;//m
+ti=150;// degree C
+ta=30;//degree C
+hw=100;// W/(m^2.C)
+ha=20;// W/(m^2.C)
+t=90;// degree C
+rho=8800;//kg/m^3
+c=400;// J/kg.C
+k=360;//W/(m.C)
+
+As=4*3.1416*R^2;
+Lc=L/2;//m
+Bi=h*Lc/k;
+
+C=120;
+tau=-rho*L*c*log((t-ta)/(ti-ta))/C
+disp("minutes",tau/60," time, Tau =")
+
+
+
diff --git a/965/CH4/EX4.32/32.sci b/965/CH4/EX4.32/32.sci new file mode 100644 index 000000000..2ce6fe94a --- /dev/null +++ b/965/CH4/EX4.32/32.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("contact surface temperature")
+disp("The rate of heat flow at a surface x =0 is given by")
+disp(" Q = -k*A*delT/(%pi*a*tau)^0.5")
+disp("Heat received by each unit area of contact surface from the body at a temperature t1 is")
+disp("Q = -k1*A*(t1-ts)/(%pi*a1*tau)^0.5")
+disp("Heat received by each unit area of contact surface from the body at a temperature t2 is")
+disp("Q = -k2*A*(ts-t2)/(%pi*a2*tau)^0.5")
+disp(" The contact surface will remain at a constant temperature if ")
+disp("-k1*A*(t1-ts)/(%pi*a1*tau)^0.5 = -k2*A*(ts-t2)/(%pi*a2*tau)^0.5")
+disp("-k1*A*(t1-ts)/(tau)^0.5 = -k2*A*(ts-t2)/(tau)^0.5")
+disp("ts(k1*a2^0.5+k2*a1^0.5)= k1*t1*a2^0.5+k2*t2*a1^0.5")
+disp("ts =(k1*t1*a2^0.5+k2*t2*a1^0.5)/(k1*a2^0.5+k2*a1^0.5)")
+disp("dividing numerator and denomenator by (a1*a2)^0.5,")
+disp("ts =(k1*t1/a1^0.5+k2*t2/a2^0.5)/(k1/a1^0.5+k2/a2^0.5)")
diff --git a/965/CH4/EX4.4/4.sci b/965/CH4/EX4.4/4.sci new file mode 100644 index 000000000..1af28d192 --- /dev/null +++ b/965/CH4/EX4.4/4.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+L=0.04;//m length of plate
+Lc=L/2;// m characteristic length of plate
+k=386;//W/m.C
+rho=9000;// kg/m^3
+C=380;//J/kg.C
+t=165;//degree C
+ta=90;// degree C
+ti=200;// degree C
+tau = 4.5*60;//sec
+disp("Temperature distribution is given by : (t-ta)/(ti-ta) = exp((-h*As*tau)/(rho*V*C))")
+m = (t-ta)/(ti-ta);
+x=(-tau)/(rho*Lc*C);
+h=(log(m))/x;
+disp("W/m^2.C",h,"the heat transfer coefficient is ")
diff --git a/965/CH4/EX4.5/5.sci b/965/CH4/EX4.5/5.sci new file mode 100644 index 000000000..ebaaba41f --- /dev/null +++ b/965/CH4/EX4.5/5.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+R=12.5/2000;//m radius of sphere
+Lc=R/3;// m characteristic length of sphere
+k=386;//W/m.C
+rho=8850;// kg/m^3
+C=400;//J/kg.C
+t=54;//degree C
+ta=28;// degree C
+ti=65;// degree C
+tau = 1.15*60;//sec
+disp("Temperature distribution is given by : (t-ta)/(ti-ta) = exp((-h*As*tau)/(rho*V*C))")
+m = (t-ta)/(ti-ta);
+x=(-tau)/(rho*Lc*C);
+h=(log(m))/x;
+disp("W/m^2.C",h,"the heat transfer coefficient is ")
diff --git a/965/CH4/EX4.6/6.sci b/965/CH4/EX4.6/6.sci new file mode 100644 index 000000000..6bc58b726 --- /dev/null +++ b/965/CH4/EX4.6/6.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("Initial cooling rate ")
+R=25/1000;//m radius of steel ball
+rho=7800;//kg/m^3
+c=2;//kJ/kg.K
+ti=900;// degree C
+ta=30;// degree C
+tau=1*60;//seconds
+h=30;// W/m^2.C
+
+//(t-ta)/(ti-ta)=exp(-h*As*tau/(rho*V*cp))
+t=ta+(ti-ta)*exp(-h*3*tau/(rho*R*c*1000));
+disp("degree C", t,"temperature t =")
+R=ti-t;
+disp("C/min",ceil(R),"Rate of cooling =")
+
diff --git a/965/CH4/EX4.7/7.sci b/965/CH4/EX4.7/7.sci new file mode 100644 index 000000000..42f361787 --- /dev/null +++ b/965/CH4/EX4.7/7.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("Ingot velocity ")
+D=10/100;//m Diameter of cylindrical ingot
+L=30/100;//m
+ti=1250;// degree C
+t=800;// degree C
+ta=90;// degree C
+k=40;// W/m.C
+h=100;// W/m^2.C
+a=1.16*10^(-5);//m^2/s
+Lc=D*L/(4*L+2*D);//m
+Lc
+Bi=h*Lc/k;
+disp(Bi,"Bi =")
+//(t-ta)/(ti-ta)=exp(-a*h*As*tau/(k*V))
+//h*As/rho*V*c =-a*h*As/(k*V)=-a*h*tau/(k*Lc)
+X=-a*h/(k*Lc);
+////(t-ta)/(ti-ta)=exp(X*tau)
+tau=(1/X)*log((t-ta)/(ti-ta));
+disp("S", tau,"time required tau =")
+Lf=6;//m furnace length
+vel=Lf/tau;
+disp("m/s",vel,"velocity of ingot passing through furnace =")
+
diff --git a/965/CH4/EX4.8/8.sci b/965/CH4/EX4.8/8.sci new file mode 100644 index 000000000..569b25de9 --- /dev/null +++ b/965/CH4/EX4.8/8.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+disp("sphere exposed to airflow ")
+R=15/2000;//m radius of steel sphere
+ti=550;// degree C
+t=90;// degree C
+ta=20;// degree C
+k=42;// W/m.C
+h=120;// W/m^2.C
+a=0.045;//m^2/h
+Lc=R/3;//m
+rho=7850;// kg/m^3
+c=475;// J/kg.C
+As=4*3.1416*R^2;
+V=4*3.1416*(R^3)/3;
+Bi=h*Lc/k;
+disp(Bi,"Bi =")
+//Fo=a*tau/Lc^2;
+//(t-ta)/(ti-ta)=exp(Bi*Fo))
+X=-log((t-ta)/(ti-ta))
+Fo=X/Bi;
+disp(Fo,"Fo =")
+tau=Fo*Lc*Lc/(a/3600);
+disp("s",tau,"time required tau =")
+Fo=7200*0.0333;
+Qi=-h*As*(ti-ta)*(exp(-1*Bi*Fo));
+disp("W",Qi,"Instantaneous heat transfer rate 2 minutes after the start of cooling Qi =")
+Q = rho*V*c*(ti-ta)*((exp(-Bi*Fo))-1);
+disp("W",Q,"Total heat energy transfer from sphere during firsh 2 minutes Q =")
diff --git a/965/CH4/EX4.9/9.sci b/965/CH4/EX4.9/9.sci new file mode 100644 index 000000000..c177318d8 --- /dev/null +++ b/965/CH4/EX4.9/9.sci @@ -0,0 +1,31 @@ +clc;
+clear all;
+disp("time for cooling")
+D=10/1000;//m Diameter of plastic sphere
+ti=75;// degree C
+t=35;// degree C
+ta=23;// degree C
+V=10;// m/s
+//for copper
+kcu=400;// W/m.K
+rhocu=8933;// kg/m^3
+ccu=380;// J/kg.C
+//for air at 23 degree C
+mu=18.16*10^(-6);// N.s/m^2
+v=15.36*10^(-6);//m^2/s
+ka=0.0258;// W/m.K
+Pr=0.709
+mus=19.78*10^(-6);// N.s/m^2 at 35 degree C
+
+Re=V*D/v
+l=Re^0.5;
+m=Re^(2/3);
+n=Pr^0.4;
+p=(mu/mus)^0.25;
+Nu=2+(0.4*l+0.06*m)*n*p
+h=ka*Nu/D;
+X=(t-ta)/(ti-ta);
+Y=-h*6/(rhocu*ccu*D);
+tau=(log (X))/Y;// sec
+disp("s",tau,"time taken to cool tau =")
+
diff --git a/965/CH6/EX6.6/6.sci b/965/CH6/EX6.6/6.sci new file mode 100644 index 000000000..0ca14b0d3 --- /dev/null +++ b/965/CH6/EX6.6/6.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("Heat transfer coefficient")
+V =[2 5 10 20]
+h =[39.5 71.2 106.5 165.3]
+Dp=50/1000;//m
+Dm=50/(5*1000);//m
+Vp=4;//m/s
+t1=140;// degree C
+t2=20;// degree C
+//(VD/v)m=(VD/v)p
+//vm=vp
+Vm=Vp*Dp/Dm;
+
+plot2d(V,h)
+xtitle("V vs h","V(m/s)","h(W/(m^2*C))")
+V=Vm;
+h=165.3;
+disp("W/(m^2*C)",h,"heat transfer ocefficient h =")
+A=3.1416*Dp*1;
+Q=A*h*(t1-t2);
+disp("W",Q,"rate of heat transfer per meter length of actual cylinder Q =")
diff --git a/965/CH7/EX7.1/1.sci b/965/CH7/EX7.1/1.sci new file mode 100644 index 000000000..11c8becc2 --- /dev/null +++ b/965/CH7/EX7.1/1.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("displacement thickness")
+disp("velocity distribution = u/U=y/d")
+disp("i) the displacement thickness, d*:")
+disp("d*=intergrate((1-u/U,U,0,d)")
+disp("d*=d/2")
+disp("ii) the momentum thickness, th")
+disp("th = integrate(u(1-u/U)/U,u,0,d)")
+disp("th=d/6")
+disp("iii) The energy thickness de")
+disp("de=integrate (u/U*(1-(u/U)^2),U,0,d")
+disp("de=d/4")
+disp("iv) The value of d*/th")
+disp("d*/th =3")
+
+
diff --git a/965/CH7/EX7.10/10.sci b/965/CH7/EX7.10/10.sci new file mode 100644 index 000000000..5a0ad2a18 --- /dev/null +++ b/965/CH7/EX7.10/10.sci @@ -0,0 +1,37 @@ +clc;
+clear all;
+disp("Laminar flow over plate")
+
+x=0.28;//m
+U=3;//m/s velocity of air
+rho=1.1374;//kg/m^3 density of air
+k=0.02732;// W/(m.C)
+cp=1005;// kJ/kg.K
+v=1.6768*10^(-5);//mm^2/s kinematic viscosity of air
+Pr=0.7;// Prandlt number
+Ts=56;// degree C
+Ta=20;// degree C
+A=0.28*0.28;//m^2
+Rex=U*x/v;// Reynold's number
+Rex
+delta=5*x*1000/(Rex)^0.5;//mm
+disp("mm",delta,"Boundary layer thickness =")
+Cfx=0.664/(Rex)^0.5;
+disp(Cfx,"local friction coefficient =")
+Cf=1.328/(Rex)^0.5;
+disp(Cf,"Average friction coefficient =")
+tau=Cfx*0.5*rho*U^2;// shear stress
+disp("N/m^2",tau,"Shear stress , =")
+deltath=delta/(Pr)^(1/3);
+disp("mm",deltath,"Thickness of thermal boundary level =")
+hx=0.332*(k/x)*Rex^0.5*Pr^(1/3);
+disp("W/(m^2.C)",hx,"Local convective heat transfer coefficient, hx =")
+h=0.664*(k/x)*Rex^0.5*Pr^(1/3);
+disp("W/(m^2.C)",h,"average convective heat transfer coefficient, h =")
+Qconv=h*A*(Ts-Ta);
+disp("W",Qconv,"Rate of heat transfer by convection, Qconv =")
+tau=0.01519;
+Fd=tau*A;
+disp("N",Fd,"drag force on one the plate, =")
+m=5*rho*U*0.00626/8;
+disp("kg/s",m,"Total mass flow rate through the boundary =")
diff --git a/965/CH7/EX7.11/11.sci b/965/CH7/EX7.11/11.sci new file mode 100644 index 000000000..68d38f47d --- /dev/null +++ b/965/CH7/EX7.11/11.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("Local HT coefficient")
+
+U=5;//m/s velocity of air
+rho=0.815;//kg/m^3 density of air
+k=0.0364;// W/(m.C)
+mu=24.5*10^(-6);//Ns/m^2 viscosity of air
+Pr=0.7;// Prandlt number
+Ts=200;// degree C
+Ta=120;// degree C
+x=0.5;//m width of plate
+v=mu/rho;
+Rex=U*x/v;// Reynold's number
+Rex
+delta=5*x*1000/(Rex)^0.5;//mm
+disp("mm",delta,"Boundary layer thickness =")
+deltath=delta/(Pr)^(1/3);
+disp("mm",deltath,"Thickness of thermal boundary level =")
+hx=0.332*(k/x)*(Rex)^0.5*Pr^(1/3);
+disp("W/(m^2.C)",hx,"Local convective heat transfer coefficient, hx =")
+
diff --git a/965/CH7/EX7.12/12.sci b/965/CH7/EX7.12/12.sci new file mode 100644 index 000000000..85aff7a4a --- /dev/null +++ b/965/CH7/EX7.12/12.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("Laminar air flow")
+
+L=2;//m length of plate
+U=5;//m/s velocity of air
+rho=0.815;//kg/m^3 density of air
+k=0.03025;// W/(m.C)
+Pr=0.6965;// Prandlt number
+Ts=120;// degree C
+Ta=40;// degree C
+v=2.107*10^(-5);//m^2/s kinematic viscosity
+
+Re=U*L/v;// Reynold's number
+
+Nu=0.664*(Re^0.5)*Pr^(1/3);
+Nu
+h=k*Nu/L;
+disp("W/(m^2.C)",h," convective heat transfer coefficient, h =")
+Q=h*(L*1)*(Ts-Ta);
+disp("W",Q,"Rate of heat transfer =")
+
diff --git a/965/CH7/EX7.13/13.sci b/965/CH7/EX7.13/13.sci new file mode 100644 index 000000000..e08461655 --- /dev/null +++ b/965/CH7/EX7.13/13.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("booundary layer thickness")
+T=27+273;// degree K
+U=2;//m/s velocity of air
+L=0.4;//m length
+mu=19.8*10^(-6);//kg/m.s
+Tp=60+273;// degree K temperature of plate
+R=287;// N.m/ kg.m gas constant
+P=10^(5);//N/m^2
+v=17.36*10^(-6);// m^2/s
+k=0.02749;//W/m.C
+Cp=1006;//J/kg.K
+Pr=0.7;// prandlt number
+rho=P/(R*T);//kg/m^3
+Re=rho*L*U/mu;
+delta=4.64*L/(Re)^0.5;
+disp("mm",delta*1000,"Boundary layer thickness =")
+mx=5*rho*U*delta/8;
+disp("kg/s",mx,"Mass flow rate per meter width =")
+Nu=0.664*Re^0.5*Pr^(1/3);
+h=k*Nu/L;
+disp("W/m^2.C",h,"Heat transfer coefficient =")
+Q=h*(L*1)*(Tp-T);
+disp("W",Q*3.6,"Heat transfered per hour =")
diff --git a/965/CH7/EX7.14/14.sci b/965/CH7/EX7.14/14.sci new file mode 100644 index 000000000..e921559db --- /dev/null +++ b/965/CH7/EX7.14/14.sci @@ -0,0 +1,26 @@ +clc;
+clear all;
+disp("booundary layer thickness")
+
+T=30+273;// degree C
+U=1.2;//m/s velocity of air
+L1=0.25;//m length
+mu=0.06717;//kg/hm
+R=287;// N.m/ kg.m gas constant
+L2=0.5;//m
+
+rho=P/(R*T);//kg/m^3
+rho
+Re1=rho*L1*U*3600/mu;
+Re1
+delta1=4.64*L1/(Re1)^0.5;
+disp("mm",delta1*1000,"Boundary layer thickness 1=")
+Re2=rho*L2*U*3600/mu;
+Re2
+delta2=4.64*L2/(Re2)^0.5;
+disp("mm",delta2*1000,"Boundary layer thickness 1=")
+mx=5*rho*U*(delta2-delta1)/8;
+disp("kg/h",mx*3600,"Mass entrainment = ")
+
+
+
diff --git a/965/CH7/EX7.15/15.sci b/965/CH7/EX7.15/15.sci new file mode 100644 index 000000000..d9a2708f1 --- /dev/null +++ b/965/CH7/EX7.15/15.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+disp("booundary layer thickness")
+
+T=20;// degree C
+Tp=100;// degree C
+U=2;//m/s velocity of air
+v=18.97*10^(-6);// kinematic viscosity
+L=0.5;//m length
+w=0.2;//m width
+k=0.025;//W/m.C
+Pr=0.7;
+disp("When flow is parallel to 500 mm side")
+Re=U*L/v;
+Re
+Nu=0.664*Re^0.5*Pr^(1/3);
+h=Nu*k/L;
+disp("W/m^2.c",h,"Heat transfer coefficient =")
+Q=h*(L*w)*(Tp-T);
+disp("W",Q,"Heat transfer rate =")
+
+disp("When flow is parallel to 200 mm side")
+Re=U*w/v;
+Re
+Nu=0.664*Re^0.5*Pr^(1/3);
+h=Nu*k/w;
+disp("W/m^2.c",h,"Heat transfer coefficient =")
+Q=h*(L*w)*(Tp-T);
+disp("W",Q,"Heat transfer rate =")
diff --git a/965/CH7/EX7.16/16.sci b/965/CH7/EX7.16/16.sci new file mode 100644 index 000000000..c7b95a2fb --- /dev/null +++ b/965/CH7/EX7.16/16.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+disp("Rate of cooling")
+
+A=1;//m^2
+T=20;// degree C
+Ts=90;// degree C
+U=2;//m/s velocity of air
+rhog=2500;// kg/m^3 density of glass
+mu=19.8*10^(-6);// N.s/m^2 viscosity
+L=1;//m length
+k=0.0286;//W/m.C
+cpa=1008;//J/kg.K
+rhoa=1.076;// kg/m^3 density of air
+
+Re=rhoa*U*L/mu;
+Pr=mu*cpa/k;
+
+Nu=0.664*Re^0.5*Pr^(1/3);
+h=Nu*k/L;
+disp("W/m^2.C",h,"Heat transfer coefficient =")
+Q=2*h*A*(Ts-T);
+disp("W",Q,"Heat transfer rate =")
+t=3/1000;// thickness
+m=rhog*A*t;// mass of glass
+cp=670;//J/kg.K
+delT=Q/(m*cp);
+disp("degree C/s",delT,"Initial heating rate =")
+
diff --git a/965/CH7/EX7.17/17.sci b/965/CH7/EX7.17/17.sci new file mode 100644 index 000000000..4b32eed35 --- /dev/null +++ b/965/CH7/EX7.17/17.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("To find velocity")
+w=1;//m width
+L=1.5;//m length
+Tp=90;// degree C
+Ta=10;// degree C
+Q=3.75*1000;// W rate of energy dissipation
+rho=1.09;// kg/m^3
+k=0.028;// W/m.C
+cp=10007;// J/kg.C
+mu=2.03*10^(-5);//kg/m-s viscosity
+Pr=0.7;
+A=L*w;//m^2
+h=Q/(A*(Tp-Ta));
+h
+Nu=h*L/k;
+Nu
+//Nu=0.664*Re^0.5*Pr^(1/3)
+Re=(Nu/(.664*Pr^(1/3)))^2;
+
+U=Re*mu/(rho*L);
+disp("m/s",U,"Velocity = ")
diff --git a/965/CH7/EX7.18/18.sci b/965/CH7/EX7.18/18.sci new file mode 100644 index 000000000..d6085eed0 --- /dev/null +++ b/965/CH7/EX7.18/18.sci @@ -0,0 +1,32 @@ +clc;
+clear all;
+disp("Heat transfer coefficient")
+Ta=20;// degree C
+Ts=100;// degree C
+U=1.8;//m/s
+L=2.2;//m
+B=1;//m
+//Properties of air
+rho=1.06;// kg/m^3
+cp=1005;//J/kg.C
+k=0.02894;// W/m.C
+Pr=0.696;
+v=18.97*10^(-6);//m^2/s
+
+Re=U*L/v;
+disp("Using exact solution: ")
+Nu=0.664*Re^0.5*Pr^(1/3);
+disp(Nu,"Nu =")
+
+h=Nu*k/L;
+disp(" W/m^2.C",h,"heat transfer coefficient =")
+Q=h*L*B*(Ts-Ta);
+disp("W",Q,"Heat transfer from plate =")
+disp("Using approximate solution: ")
+Nu=0.646*Re^0.5*Pr^(1/3);
+disp(Nu,"Nu =")
+h=Nu*k/L;
+disp(" W/m^2.C",h,"heat transfer coefficient =")
+Q=h*L*B*(Ts-Ta);
+disp("W",Q,"Heat transfer from plate =")
+
diff --git a/965/CH7/EX7.19/19.sci b/965/CH7/EX7.19/19.sci new file mode 100644 index 000000000..b2e0289e9 --- /dev/null +++ b/965/CH7/EX7.19/19.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("skin friction coefficient")
+Ta=30;// degree C
+U=1.8;//m/s
+L=0.75;//m
+rho=1.165;// kg/m^3
+v=16*10^(-6);//m^2/s
+mu=6.717*10^(-6);//kg/hm
+Re=U*L/v;
+Cf=1.328/Re^0.5;
+disp(Cf,"Average skin friction Cf =")
+tau=0.5*rho*U^2*Cf;
+disp("N/m^2",tau,"Average shear stress Tau =")
+
+Cfx=0.664/Re^0.5;
+disp(Cfx," skin friction coefficient at the trailing edge, Cf =")
+taux=0.5*rho*U^2*Cfx;
+R=tau/taux;
+
+disp(R,"Ratio of average shear stress to the shear stress at the trailing edge R =")
+
diff --git a/965/CH7/EX7.2/2.sci b/965/CH7/EX7.2/2.sci new file mode 100644 index 000000000..aa1a790fa --- /dev/null +++ b/965/CH7/EX7.2/2.sci @@ -0,0 +1,13 @@ +clc;
+clear all;
+disp("i) displacement thickness to boundary thickness ratio")
+disp("velocity distribution: u/U=3y/(2*d)-y^2/(2*d^2)")
+disp("d* = integrate (1-3y/(2*d)-y^2/(2*d^2),y,0,d)")
+disp("d*/d = 5/12")
+disp("displacement thickness to bloundary thickness ratio : d*/d =5/12")
+disp("ii) momentum thickness to boundary layer thickness ratio")
+disp("th = integrate(u/U*(1-u/U),y,0,d)")
+disp("th = integrate(((1-3y/(2*d)-y^2/(2*d^2))*(1-((1-3y/(2*d)-y^2/(2*d^2))),y,0,d)")
+disp("thus, th/d = 19/120")
+disp(" momentum thickness to boundary layer thickness ratio = 19/120")
+
diff --git a/965/CH7/EX7.20/20.sci b/965/CH7/EX7.20/20.sci new file mode 100644 index 000000000..9a42330bb --- /dev/null +++ b/965/CH7/EX7.20/20.sci @@ -0,0 +1,28 @@ +clc;
+clear all;
+disp("Heat loss calculation")
+ta=30;//degree C
+ts=90;// degree C
+U=2.8;// m/s
+v=18.97*10^(-6);// m^2/s
+kp=25;// W/m.C
+L=1;//m
+ka=0.02894;// W/m.C
+rho=1.06;//kg/m^3
+Cp=1005;//J/kg.K
+L=1;//m
+B=600/1000;// m
+Pr=0.696;
+delta = 25/1000;//m
+disp("i)Heat lost by the plate :")
+Re = U*L/v;// Reynold's number at trailing edge
+Nu=0.664*(Re^0.5)*(Pr^(1/3));
+h=Nu*ka/L;// W/m^2.C
+As=1*0.6;//m^2;// W
+Q=h*As*(ts-ta);
+disp("W",Q,"Heat loss by the plate is ")
+disp("ii) Bottom temperature of plate, tb :")
+tb = -1*Q*delta/(kp*As)+ts;// degree C
+disp("degree C",tb,"Bottom temperature of the plate is ")
+
+
diff --git a/965/CH7/EX7.21/21.sci b/965/CH7/EX7.21/21.sci new file mode 100644 index 000000000..a4c7db719 --- /dev/null +++ b/965/CH7/EX7.21/21.sci @@ -0,0 +1,36 @@ +clc;
+clear all;
+disp("heat transfer rate")
+ta=30;//degree C
+U=2.2;//m/s
+v=18.97*10^(-6);// m^2/s
+ts=90;// degree C
+L=900/1000;//m
+B=0.45;//m
+Pr=0.696;
+k=0.02894;//W/m.C
+rho=1.06;//kg/m^3
+mu=7.211;//kg/hm
+disp("i) Heat transfer rate from first half of the plate")
+// for first half of the plate,
+x=L/2;
+Rex=U*x/v;
+if(Rex<5*10^5)
+disp("Flow is laminar")
+end
+Nux=0.332*(Rex^0.5)*Pr^(1/3);
+hx=Nux*k/x;
+ha=2*hx;// average heat transfer rate
+Qx=ha*x*B*(ts-ta);//W
+disp("W",Qx,"Heat transfer rate from first half of the plate, Qx =")
+disp("ii) heat transfer from full plate")
+// for full plate
+x=L;
+ReL=U*x/v;
+NuL=0.664*ReL^0.5*Pr^(1/3);
+h=NuL*k/x;
+QL=h*L*B*(ts-ta);//W
+disp("W",QL,"Heat transfer rate from entire plate QL =")
+disp("iii) heat transfer rate from next half of the plate")
+Q=QL-Qx;
+disp("W",Q,"heat transfer rate from next half of the plate Q =")
diff --git a/965/CH7/EX7.22/22.sci b/965/CH7/EX7.22/22.sci new file mode 100644 index 000000000..4a5347e2a --- /dev/null +++ b/965/CH7/EX7.22/22.sci @@ -0,0 +1,31 @@ +clc;
+clear all;
+disp("Boundary layer thickness")
+ta=25;// degree C
+U=0.1;//m/s
+v=0.65*10^(-4);// m^2/s
+ts=95;// degree C
+L=4.5;//m
+k=0.213;//W/m.C
+rho=956.8;//kg/m^3
+a=7.2*10^(-8);//m^2/s
+disp("i) The hydrodynamic and thermal boundary layer thickness, del, delth")
+ReL=U*L/v;// Reynolds number at the end of the plate
+del=5*L/ReL^0.5;// hydrodynamic boundary layer thickness
+disp("mm",del*1000,"hydrodynamic boundary layer thickness, del =")
+Pr=v/a;
+delth=del/Pr^(1/3);//Thermal boundary layer thickness according to Pohlhausen
+disp("mm",delth*1000,"Thermal boundary layer thickness, del =")
+disp("ii) the total drag force per unit width on one side of plate. Fd :")
+Cf=1.328/ReL^0.5;
+Fd=Cf*(0.5*rho*U^2)*(L*1);// N/m width The drag force
+disp("N/m width",Fd,"The drag force, Fd = ")
+disp("iii) The total heat transfer coefficient at the trailing edge, hx (x =L)")
+Nux=0.332*ReL^0.5*Pr^(1/3);
+hx=Nux*k/L;
+disp("W/m^2.C",hx, "The total heat transfer coefficient, hx =")
+disp("iv) The heat transfer rate")
+ha=2*hx;
+As=L*1;
+Q=ha*As*(ts-ta);//W
+disp("W",Q,"Heat transfer rate")
diff --git a/965/CH7/EX7.23/23.sci b/965/CH7/EX7.23/23.sci new file mode 100644 index 000000000..aa75c266a --- /dev/null +++ b/965/CH7/EX7.23/23.sci @@ -0,0 +1,31 @@ +clc;
+clear all;
+disp("boundary layer thickness")
+ta=20;//degree C
+U=4.5;//m/s
+v=16.96*10^(-6);// m^2/s
+ts=60;// degree
+Pr=0.699
+k=0.02755;//W/m.C
+rho=1.128;//kg/m^3
+Re=5*10^5;
+xc=Re*v/U;//m distance from the leading edge at which the flow in boundary layer changes from laminar to turbulent
+del=4.64*xc/Re^0.5;//m
+disp("mm",del*1000,"Thickness of hydrodynamic layer =")
+delth=del/Pr^(1/3);
+disp("mm",delth*1000,"Thermal boundary layer =")
+Nuc=0.332*Re^0.5*Pr^(1/3);
+hc=Nuc*k/xc;
+disp("W/m^2.C",hc,"local heat transfer coefficient =")
+h=2*hc;//Average heat transfer coefficient
+disp("W/m^2.C",h,"average heat transfer coefficient =")
+As=1.88*1;
+Q=h*2*As*(ts-ta);// W
+disp("W",Q,"Heat transfer rate from both sides for, unit width of the plate, Q =")
+del1=0;//m
+del2=del;//m
+m=5/8*rho*U*(del2-del1);// kg/s
+mh=m*3600;//kg/hr
+disp("kg/hr",mh, "Mass entrainment in boundary layer =")
+Cfx=0.646/Re^0.5;//skin friction coefficient
+disp(Cfx, "Skin friction coefficient =")
diff --git a/965/CH7/EX7.24/24.sci b/965/CH7/EX7.24/24.sci new file mode 100644 index 000000000..98973af3c --- /dev/null +++ b/965/CH7/EX7.24/24.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("Boundary layer thickness")
+ta=20;//degree C
+U=1.8;//m/s
+L=0.6;//m
+rho=1.205;//kg/m^3
+mu=0.06533/3600;//kg/ms
+disp("boundary layer thickness by exact solution : del=5*(v*x/U)^0.5")
+disp("at the midpoint of the boundary layer y= del/2 occurs at ")
+disp("nu = y*(U/v*x)=2.5")
+disp("thus we get u/U =0.736")
+disp("m/s",U*0.736,"u =")
+ReL=rho*U*L/mu;
+delL=5*L/ReL^0.5;
+disp("m",delL,"The maximum boundary layer thickness, delL =")
+disp("The maximum value of normal component of velocity occurs at the outer edge of the boundary layer where u =U")
+//u/U*ReL^0.5=0.86;
+u=0.86*U/ReL^0.5;
+disp("m/s",u,"the maximum value of normal component of velocity at the trailing edge is ")
diff --git a/965/CH7/EX7.25/25.sci b/965/CH7/EX7.25/25.sci new file mode 100644 index 000000000..dc2b06a97 --- /dev/null +++ b/965/CH7/EX7.25/25.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("Average velocity")
+R=0.12;// radius of circular tube
+ts=90;//degree C
+disp("u = 2.7*r-3.2*r^2")
+u=(2/R^2)*integrate('2.7*r-3.2*r^2','r',0,R);
+disp("m/s",u,"Average velocity =")
+disp("t=85*(1-2.2*r)")
+m=integrate('(2.7*r-3.2*r^2)*(85*(1-2.2*r)*r)','r',0,R);
+n=integrate('(2.7*r-3.2*r^2)*r','r',0,R);
+tb=m/n;
+disp("degree C",tb,"mean bulk temperature tb =")
+Q=1000;//kJ/h
+Q=Q*1000/3600;//J/s
+A=2*%pi*R*1;
+h=Q/(A*(ts-tb));
+disp("W/m^2.C",h,"Heat transfer coefficient, h =")
+
+
+
diff --git a/965/CH7/EX7.26/26.sci b/965/CH7/EX7.26/26.sci new file mode 100644 index 000000000..529d73c82 --- /dev/null +++ b/965/CH7/EX7.26/26.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("required tube length")
+ti=60;// degree C
+d=1/100;//m diameter of tube
+ta=40;//degree C
+t=45;//degree C
+rho=865;//kg/m^3
+k=0.14;// W/m.K
+cp=1780;//J/kg.C
+U=3;//m/s
+Nu=3.657
+Af=%pi*d^2/4;// m^2 flow area
+m=rho*Af*U;
+Q=m*cp*(ti-t);
+h=Nu*k/d;// W/m^2.K
+t1=ti-ta;
+t2=t-ta;
+tm=(t1-t2)/log(t1/t2);// degree C
+//A=%pi*d*L
+L=Q/(h*%pi*d*tm);
+disp("m",L,"Required tube length is L =")
diff --git a/965/CH7/EX7.27/27.sci b/965/CH7/EX7.27/27.sci new file mode 100644 index 000000000..1a2cafbfb --- /dev/null +++ b/965/CH7/EX7.27/27.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("required tube legth")
+m=0.5;//mg/min
+D=0.02;//m
+v=0.478*10^(-6);//m^2/s
+cp=4.178*10^3;//J/kg.K
+Nu=3.65;
+rho=983.2;//k/m^3
+k=0.659;//W/m.C
+ti=20;// degree C
+to=50;// degree C
+ta=85;//degree C
+A=%pi*D^2/4;//m^2
+m=m/60;//kg/sec
+u=m/(rho*A);//m/s
+Re=D*u/v;
+h=Nu*k/D
+tb=(ti+to)/2;//degree C
+Q=m*cp*(to-ti)
+L=Q/(%pi*D*h*(ta-tb));//m
+disp("m",L,"length of tube required for fully developed flow, L =")
+
diff --git a/965/CH7/EX7.28/28.sci b/965/CH7/EX7.28/28.sci new file mode 100644 index 000000000..8b9d86395 --- /dev/null +++ b/965/CH7/EX7.28/28.sci @@ -0,0 +1,13 @@ +clc;
+clear all;
+disp("drag force value")
+L=5;//m
+W=0.75;//m
+U=5;//m/s
+v=0.011*10^(-4);//m^2/s/m^3
+rho=1000;//kg
+ReL=U*L/v;// reynolds number at the end of plate
+A=L*W;
+Cf=0.455/(log10(ReL))^2.58;
+Fd=2*Cf*(0.5*rho*A*U^2);
+disp("N",Fd,"Drag force =")
diff --git a/965/CH7/EX7.29/29.sci b/965/CH7/EX7.29/29.sci new file mode 100644 index 000000000..f314f6030 --- /dev/null +++ b/965/CH7/EX7.29/29.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("Total power required")
+L=50;//m
+D=5;//m
+U=8;//m/s
+ta=20;// degree C
+rho=1030;//kg/m^3
+v=10^(-6);//m^2/s
+ReL=U*L/v;
+Rex=5*10^5;
+x=Rex*v/U;
+Cf=0.455/(log10(ReL))^2.58;
+A=%pi*D*L;//m^2
+Fd=Cf*0.5*rho*A*U^2;
+P=Fd*U/1000;//kW
+disp("kW",P,"Power required =")
diff --git a/965/CH7/EX7.3/3.sci b/965/CH7/EX7.3/3.sci new file mode 100644 index 000000000..e5d1ff7ff --- /dev/null +++ b/965/CH7/EX7.3/3.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("velocity distribution")
+disp("velocity distribution : u =a+b*y+c*y^2")
+disp("the following boundary conditions must be satisfied:")
+disp("at y = 0, u= 0")
+disp("0 =a+0+0")
+disp("hence a =0")
+disp("at y =d, du/dy = 0")
+disp("b+2*c*d =0")
+disp("b=-2*c*d")
+disp(" at y = d, u = U")
+disp("U=b*d+c*d^2")
+disp("U = -2*c*d*d+c*d*d")
+disp("c =-U/d^2")
+disp("b = 2*U/d")
+disp("u =2*U/d*y-U*y^2/d^2")
+disp("u/U = 2(y/d)-(y/d)^2")
+
diff --git a/965/CH7/EX7.30/30.sci b/965/CH7/EX7.30/30.sci new file mode 100644 index 000000000..430bdeab9 --- /dev/null +++ b/965/CH7/EX7.30/30.sci @@ -0,0 +1,13 @@ +clc;
+clear all;
+disp("turbulent boundary layer")
+disp("Cf=0.072/ReL^0.2")
+disp("For entire plate, ReL=U*L/v")
+disp("For first half of the plate, Rex= U*L/(2*v)")
+disp("Drag force per unit width for entire plate is, Fd=Cf*rho*U^2/2*Area per unit width")
+disp("Drag force per unit width for entire plate is, Fd=Cf*rho*U^2/2*L")
+disp("similarly the drag force per unit width for the front half portion of the plate is")
+disp("Fd1 = (0.072/ReL^0.2)*rho*U^2/2*L/2")
+disp("Fd2=Fd-Fd1 = (0.072/ReL^0.2)*rho*U^2/2*L/2(1-0.5*2^0.2)")
+disp(" Fd1/Fd2 = (0.5*2^(1/5))/(1-0.5*2^(1/5))")
+disp("Fd1/Fd2 =1.347")
diff --git a/965/CH7/EX7.31/31.sci b/965/CH7/EX7.31/31.sci new file mode 100644 index 000000000..f175e6af7 --- /dev/null +++ b/965/CH7/EX7.31/31.sci @@ -0,0 +1,15 @@ +clc;
+clear all;
+disp("surface drag of train")
+L=200;//m
+p=9;//m perimeter above wheels
+v=1.5*10^(-5);//m^2/s
+rho=1.24;//kg/m^3
+u=90;//km/h
+U=u*5/18;//m/s
+A=L*p;
+ReL=U*L/v;
+Cf=0.455/(log10(ReL))^2.58-1670/ReL;
+Fd=Cf*0.5*rho*A*U^2;
+disp("N",Fd,"Drag force =")
+
diff --git a/965/CH7/EX7.32/32.sci b/965/CH7/EX7.32/32.sci new file mode 100644 index 000000000..204d819f5 --- /dev/null +++ b/965/CH7/EX7.32/32.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("Total drag force")
+L=30;//m
+A=30*10;//m^2
+U=0.6;//m/s
+ReL=5*10^5;
+rho=998;//kg/m^3
+v=10^(-6);//m^2/s
+xc=ReL*v/U;//m
+del=5*xc/ReL^0.5;//m
+disp("mm",del*1000,"Maximum boundary layer thickness =")
+ReL=U*L/v;
+Cf=0.455/(log10(ReL))^2.58-1670/ReL;
+Fd=Cf*0.5*rho*A*U^2;//N
+disp("N",Fd,"The total drag force =")
+P=Fd*U;//W
+disp("W",P,"Power required =")
diff --git a/965/CH7/EX7.33/33.sci b/965/CH7/EX7.33/33.sci new file mode 100644 index 000000000..82924fa1d --- /dev/null +++ b/965/CH7/EX7.33/33.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("percentage error calculation")
+ta=20;// degree C
+U=10;//m/s
+L=5;//m
+B=3;//m
+ts=40;//degree C
+Recr=5*10^5;
+k=0.0263;//W/m.C
+v=15.89*10^(-6);//m^2/s
+Pr=0.707;
+ReL=U*L/v;
+Nu=0.0375*(ReL^0.8-23200)*Pr^(1/3);
+h=Nu*k/L;
+A=L*B;
+Q1=ceil(h*A*(ts-ta))// combination of laminar and turbulent
+
+Nu=0.0375*(ReL^0.8)*Pr^(1/3);
+h=Nu*k/L;
+Q2=ceil(h*A*(ts-ta))// if entire boundary layer is assumed as turbulent
+e=(Q2/Q1-1)*100;
+disp("%",e,"Percentage error =")
+
+
diff --git a/965/CH7/EX7.34/34.sci b/965/CH7/EX7.34/34.sci new file mode 100644 index 000000000..aa1704eff --- /dev/null +++ b/965/CH7/EX7.34/34.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("local HT coefficient")
+U=50;//m/s
+Cfx=0.004;
+k=0.035;//W/m.C
+cp=1001;//J/kg.K
+rho=0.88;//kg/m^3
+mu=2.286*10^(-5);//kg.m/s
+Pr=mu*cp/k
+m=rho*cp*U
+//St=hx/m
+//St*Pr^(2/3)=Cfx/2
+St=Cfx/(2*Pr^(2/3))
+hx=St*m;
+disp("W/m^2.K",hx,"local HT coefficient, hx = ")
diff --git a/965/CH7/EX7.35/35.sci b/965/CH7/EX7.35/35.sci new file mode 100644 index 000000000..dc55712c4 --- /dev/null +++ b/965/CH7/EX7.35/35.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("Hear loss from crank")
+A=80*20*10^(-4);//m^2
+ta=15;//degree C
+U=25;//m/s
+ts=85;// degree C
+L=0.8;//m
+B=0.2;//m
+Pr=0.698
+k=0.02824;//W/m.C
+v=17.95*10^(-6);// m^2/s
+ReL=U*L/v;
+Nu=0.036*(ReL^0.8)*Pr^(1/3);
+h=Nu*k/L;
+Q=h*A*(ts-ta);//W
+disp("W",Q,"Heat loss from crank is Q=")
diff --git a/965/CH7/EX7.36/36.sci b/965/CH7/EX7.36/36.sci new file mode 100644 index 000000000..7d1b7177d --- /dev/null +++ b/965/CH7/EX7.36/36.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("heat transfer from plate")
+ta=20;//degree C
+U=40;//m/s
+ts=60;// degree C
+L=1;//m
+B=1;//m
+Pr=0.699;
+k=0.0275;//W/m.C
+v=16.96*10^(-6);// m^2/s
+rho=1.128;//kg/m^3
+cp=1005;//J/kg.K
+ReL=U*L/v;;
+Nu=(0.037*(ReL^0.8)-850)*Pr^(1/3)
+h=Nu*k/L;
+Q=h*L*B*(ts-ta);//W
+disp("W",Q,"Heat loss from plate is Q=")
diff --git a/965/CH7/EX7.37/37.sci b/965/CH7/EX7.37/37.sci new file mode 100644 index 000000000..f96a1ad5e --- /dev/null +++ b/965/CH7/EX7.37/37.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("heat loss from gases")
+U=70;//m/s
+L=1.2;//m
+B=0.8;//m
+ts=950;//degree C
+ta=280;//degree C
+ReL=5*10^5;
+Pr=0.625;
+k=0.075;//W/m.C
+v=95*10^(-6);// m^2/s
+ReL=U*L/v;
+Nu=(0.036*(ReL^0.8)-836)*Pr^(1/3)
+h=Nu*k/L;
+Q=h*L*B*(ts-ta);//W
+disp("kW",Q/1000,"Heat loss from crank is Q=")
diff --git a/965/CH7/EX7.38/38.sci b/965/CH7/EX7.38/38.sci new file mode 100644 index 000000000..a325f4356 --- /dev/null +++ b/965/CH7/EX7.38/38.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("heat transfer from surface")
+ta=20;//degree C
+U=35;//m/s
+ts=60;// degree C
+L=0.75;//m
+B=1;//m
+mu=1.906*10^(-5);//kg.m/s
+cp=1007;//J/kg.K
+k=0.0272;//W/m.C
+P=1.0132*10^5;//Pa
+R=287;
+Pr=mu*cp/k
+rho=P/(R*(ta+273))//kg/m^3
+ReL=rho*U*L/mu
+Nu=(0.037*(ReL^0.8)-850)*Pr^(1/3);
+h=Nu*k/L
+Q=h*L*B*(ts-ta);//W
+disp("W",Q,"Heat loss from surface is Q=")
diff --git a/965/CH7/EX7.39/39.sci b/965/CH7/EX7.39/39.sci new file mode 100644 index 000000000..92a569717 --- /dev/null +++ b/965/CH7/EX7.39/39.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("velocity of air")
+ta=10;//degree C
+ts=90;// degree C
+L=1.5;//m
+B=1;//m
+mu=2.209*10^(-5);//kg.m/s
+cp=1007.3;//J/kg.C
+k=0.02813;//W/m.C
+rho=1.0877;//kg/m^3
+Pr=0.703;
+Q=3.75*1000;//W
+As=L*B;
+h=Q/(As*(ts-ta));
+Nu=h*L/k;
+ReL=((Nu/Pr^(1/3)+836)/0.036)^(1/0.8)
+U=ReL*mu/(rho*L);
+disp("m/s",U,"Velocity of air is")
diff --git a/965/CH7/EX7.4/4.sci b/965/CH7/EX7.4/4.sci new file mode 100644 index 000000000..ee2d07b93 --- /dev/null +++ b/965/CH7/EX7.4/4.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("Boundary layer thickness")
+//uU=X
+//y/delta=Y
+//X=2*Y-Y^2;
+L=1.5;//m length of plate
+w=1;// m width of plate
+v=0.12;// m/s velocity of water
+mu=10^(-3);// N-s/m^2
+U=0.12;//m/s free stream velocity
+rho=1000;//kg/m^3 density of water
+ReL=rho*U*L/mu;
+delta=5.48*L*1000/(ReL)^0.5;//mm
+disp("mm",delta,"thickness of boundary layer =")
+Cf=1.46/((ReL)^0.5);// coefficent of drag
+disp(Cf,"Coefficient of drag =")
+
diff --git a/965/CH7/EX7.40/40.sci b/965/CH7/EX7.40/40.sci new file mode 100644 index 000000000..a450ff495 --- /dev/null +++ b/965/CH7/EX7.40/40.sci @@ -0,0 +1,26 @@ +clc;
+clear all;
+disp("Heat loss from wing")
+U=450*1000/3600//m/s
+L=6;//m
+B=1.2;//m
+p=1.013*65/76*10^5;//Pa
+R=287;
+k=0.2511;//W/m.C
+v=14.16*10^(-6);//m^2/s
+Pr=0.705;
+ta=10;//degree C
+rho=p/(R*(ta+273));//kg/m^3
+ReL=U*B/v;
+Rec=5*10^5;
+xc=Rec*v/U;//m
+Nu=(0.036*ReL^0.8-836)*Pr^(1/3);
+h=Nu*k/B;
+A=L*B;
+delT=19-1;//degree C
+Q=h*A*delT;//W
+disp("W",Q,"Heat loss from wing =")
+Cf=(0.072/ReL^0.2-1670/ReL);
+Fd=Cf*0.5*rho*A*U^2;
+disp("N",Fd,"Drag force on the wing =")
+
diff --git a/965/CH7/EX7.41/41.sci b/965/CH7/EX7.41/41.sci new file mode 100644 index 000000000..5ed59b317 --- /dev/null +++ b/965/CH7/EX7.41/41.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+Fd=10.5;//N
+ts=95;//degree C
+ta=25;//degree C
+U=30;//m/s
+rho=1.06;//kg/m^3
+cp=1005;//J/kg.K
+v=18.97*10^(-6);// m^2/s
+Pr=0.696;
+//ReL=U*L/v
+//Cf=0.072/ReL^0.2
+//A=L^2;
+//F=Cf*0.5*rho*A*U^2;
+//10.5=2.05*L^0.8
+L=(10.5/2.05)^(1/1.8)
+ReL=U*L/v;
+Cf=0.072/ReL^0.2;
+h=rho*cp*U*Cf/(2*Pr^(2/3));
+disp("W/m^2.C",h,"Heat transfer coefficient =")
+Q=h*L^2*(ts-ta);
+disp("W",Q,"Heat lpss from plate surface = ")
diff --git a/965/CH7/EX7.42/42.sci b/965/CH7/EX7.42/42.sci new file mode 100644 index 000000000..909012ba9 --- /dev/null +++ b/965/CH7/EX7.42/42.sci @@ -0,0 +1,26 @@ +clc;
+clear all;
+disp("heat transfer from plate")
+L=0.8;//m
+U=45;//m/s
+ts=300;//degree C
+ta=20;// degree C
+Re=5*10^5;
+k=0.03638;// W/m.C
+v=30.08*10^(-6);//m^2/s
+Pr=0.682;
+xc=Re*v/U;
+h=0.664*(k/xc)*Re^0.5*Pr^(1/3);
+A=xc*1;
+Qlam=h*A*(ts-ta);
+disp("W",Qlam,"Heat transfer from laminar portion =")
+ReL=U*L/v;
+h=0.036*k/(L-xc)*(ReL^0.8-Re^0.8)*Pr^(1/3)
+Qturb=h*(0.8-A)*(ts-ta);
+disp("W",Qturb,"Heat transfer from turbulent portion =")
+Qtotal=Qlam+Qturb;
+disp("W",Qtotal,"Heat transfer from both portions =")
+h=0.036*k/L*(ReL^0.8)*Pr^(1/3);
+Qt=h*L*(ts-ta);
+e=(Qt/Qtotal-1)*100;
+disp("%",e,"Percentage error =")
diff --git a/965/CH7/EX7.43/43.sci b/965/CH7/EX7.43/43.sci new file mode 100644 index 000000000..2b878312a --- /dev/null +++ b/965/CH7/EX7.43/43.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("average HT coefficient")
+D=2/100;//m diameter of tube
+tf=30;//degree C
+m=2940;//kg/h
+ts=100;// degree C
+L=5;//m
+k=0.12;//W/m.C
+cp=2000;//J/kg.K
+v=5.14*10^(-6);// m^2/s
+rho=850;//kg/m^3
+m1=m/3600;//kg/s
+As=%pi*D^2/4;
+U=m1/(As*rho)//m/s
+Pr=v*rho*cp/k
+ReL=10^3*ceil(U*D/v/10^3)
+Nu=0.023*(ReL^0.8)*Pr^(1/3)
+h=Nu*k/D;
+disp("W/m^2.C",h,"Average heat transfer coefficiet h =")
+
diff --git a/965/CH7/EX7.44/44.sci b/965/CH7/EX7.44/44.sci new file mode 100644 index 000000000..56a0cb13f --- /dev/null +++ b/965/CH7/EX7.44/44.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("HT coefficient from tube")
+D=0.06;//m diameter of tube
+U=12;//m/s
+ti=15;//degree C
+to=45;//degree C
+ts=70;// degree C
+k=61.714/100;//W/m.C
+cp=4174;//J/kg.K
+v=0.805*10^(-6);// m^2/s
+rho=995.7;//kg/m^3
+Pr=5.42;
+ReL=U*D/v
+Nu=0.023*(ReL^0.8)*Pr^(1/3)
+h=Nu*k/D;
+disp("W/m^2.C",h,"heat transfer coefficiet from tube surface h =")
+m=rho*%pi/4*D^2*U;// kg/s
+Q=m*cp*(to-ti);//W
+tb=(ti+to)/2;
+disp("W",Q,"The heat transferred Q =")
+L=Q/(h*%pi*D*(ts-tb));
+disp("m",L,"The length of tube is L =")
diff --git a/965/CH7/EX7.45/45.sci b/965/CH7/EX7.45/45.sci new file mode 100644 index 000000000..4ba0b751e --- /dev/null +++ b/965/CH7/EX7.45/45.sci @@ -0,0 +1,28 @@ +clc;
+clear all;
+disp("Required tube length")
+m=50/60;//kg/sec
+di=2.5/100;//m inner diameter
+ts=100;// degree C
+ti=25;// degree C
+to=55;// degree C
+cp=4187;//J/kg.C
+t1=100-25;
+t2=100-55;
+tm=(t1-t2)/log(t1/t2);
+Q=m*cp*(to-ti);//W
+As=%pi/4*di^2;
+;tw=(ts+(ti+to)/2)/2;// degree C temperature at which the properties of water should be taken
+mu=405*10^(-6);// kg.m/s
+rho=977.8;//kg/m^3
+k=66.72/100;//W/m.C
+U=m/(As*rho);//m/s
+Re=rho*U*di/mu;
+Pr=mu*cp/k;
+Nu=0.023*Re^0.8*Pr^0.4;
+h=Nu*k/di;// W/m^2.C
+L=Q/(h*%pi*di*tm);//m
+disp("m",L,"Required tube length =")
+
+
+
diff --git a/965/CH7/EX7.46/46.sci b/965/CH7/EX7.46/46.sci new file mode 100644 index 000000000..5ebd3615f --- /dev/null +++ b/965/CH7/EX7.46/46.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("heat transfer rate")
+tw=25;//degree C
+D=1.5/100;//m outer diameter of copper tube
+U=2;//m/s
+t=75;//degree C
+rho=988;//kg/m^3
+k=0.648;//W/m.K
+mu=549.2*10^(-6);// kg.m/s
+cp=4174;//J/kg.K
+Re=rho*U*D/mu;
+Pr=mu*cp/k;
+Nu=0.3+0.62*(Re^0.5)*(Pr^(1/3))*(1+(Re/282000)^0.5)/(1+(0.4/Pr)^(2/3))^0.25;
+h=Nu*k/D;
+Ql=h*%pi*D*(t-tw);
+disp("W/m",Ql,"heat transfer rate per unit length is Q/L =")
diff --git a/965/CH7/EX7.47/47.sci b/965/CH7/EX7.47/47.sci new file mode 100644 index 000000000..88e206dc9 --- /dev/null +++ b/965/CH7/EX7.47/47.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("incerease in bulk temperature")
+tb1=200;//degree C
+d=25.4/1000;//m diameter of tube
+U=10;//m/s
+tw=20;// degree C
+L=3;//m length of tube
+rho=1.493;//kg/m^3
+mu=2.57*10^(-5);//Ns/m^2
+k=0.0386;//W/m.C
+cp=1025;// J/kg.C
+Re=rho*U*d/mu
+Pr=mu*cp/k
+Nu=0.0023*Re^0.8*Pr^0.4
+h=Nu*k/d
+Q=h*%pi*d*(tb1-tw)
+m=rho*%pi*d^2*U;
+delT=Q/(m*cp);
+disp("degree C",delT,"Increase in bulk temperature is = ")
+
diff --git a/965/CH7/EX7.48/48.sci b/965/CH7/EX7.48/48.sci new file mode 100644 index 000000000..27cbb7cb9 --- /dev/null +++ b/965/CH7/EX7.48/48.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("heat transfer rate")
+d=300/1000;//m diameter
+L=3.5;//m
+delT=40;//degree C =ts-ti
+f=0.022;// friction factor
+St=f/2;
+disp("The energy balance yields Q=h*A*(ts-ta)=m*cp*(to-ti)")
+disp("h*(%pi*D*L)*(ts-(to+ti)/2)=rho*(%pi*D^2*U/4)*cp(to-ti)")
+disp("(h/(rho*U*cp))*L*(ts-to+ts-ti)/2=D/4*(to-ti)")
+disp("St*L/2*(ts-to+ts-ti)=D/4*((ts-ti)-(ts-to))")
+disp("f/8*L/2*(ts-to+ts-ti)=D/4*((ts-ti)-(ts-to))")
+disp("thus by putting the values, ")
+
+t1=(d/4-f/8*L/2)*delT/(f/8*L/2+d/4)// ts-to
+t=delT-t1;
+disp("degree C",t,"Rise in the temperature of fluid at the end =")
+
diff --git a/965/CH7/EX7.49/49.sci b/965/CH7/EX7.49/49.sci new file mode 100644 index 000000000..b72315478 --- /dev/null +++ b/965/CH7/EX7.49/49.sci @@ -0,0 +1,28 @@ +clc;
+clear all;
+disp("bulk temperature increase")
+p=2*10^5;// Pa pressure of air
+d=30/1000;//m tube diameter
+U=10;//m/s
+tw=100;//degree C wall temperature
+mu=20.6*10^(-6);// Ns/m^2
+Pr=0.694;
+cp=1009;// J/kg.C
+k=0.0297;// kg/m.C
+ti=40;//degree C air temperature
+rho=p/(287*(ti+273));// kg/m^3
+Re=rho*U*d/mu;
+Nu=0.023*Re^0.8*Pr^0.4;
+h=Nu*k/d
+disp("Q=h*A*(AMTD)=m*cp*(to-ti)")
+disp("where AMTD = (tw-(ti+to)/2)")
+A=%pi*d*1;// m^2
+m=%pi*d^2*U*rho/4// kg/s
+to=(h*A*(tw-ti/2)+m*cp*ti)/(m*cp+h*A/2);
+disp("degree C",to,"Thus rise in bulk temperature of air =")
+Q=m*cp*(to-ti);
+disp("W/m",Q,"heat transefer rate =")
+
+
+
+
diff --git a/965/CH7/EX7.5/5.sci b/965/CH7/EX7.5/5.sci new file mode 100644 index 000000000..7e92e37ee --- /dev/null +++ b/965/CH7/EX7.5/5.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("Boundary layer thickness")
+//uU=X
+//y/delta=Y
+//X=2*Y-Y^2;
+L=1.1;//m length of plate
+w=0.9;// m width of plate
+Re=2*10^5;// Reynold's number
+v=0.15*10^(-4);//m^2/s stokes kinematic viscocity
+U=12;//m/s velocity ofair
+x=Re*v/U;
+disp("m",x,"Maximum distance from the leading edge upto which laminar boundary layer exists, x =")
+
+delta=5.48*x*1000/(Re)^0.5;//mm
+disp("mm",delta,"Maximum thickness of boundary layer =")
+
diff --git a/965/CH7/EX7.50/50.sci b/965/CH7/EX7.50/50.sci new file mode 100644 index 000000000..964f2eeba --- /dev/null +++ b/965/CH7/EX7.50/50.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("heat transferred per meter")
+ta=15+273;//K air temperature
+ts=605+273;//K plate temperature
+U=6.5;// m/s velocity of air
+x=0.35;//m distance
+tf=(ts+ta)/2;// mean film temperature
+rho=0.614;//kg/m^3
+cp=1046;//J/kg.K
+k=0.04593;// W/m.C
+mu=29.7*10^(-6);//kg/m.s
+Pr=0.675;,
+Re=rho*U*x/mu;
+Nux=0.332*Pr^(1/3)*Re^0.5*(ts/ta)^0.117;
+hx=Nux*k/x;
+h=2*hx;
+Q=2*h*x*1*(ts-ta);
+disp("W",Q,"heat transfer from both sides of the plate, per meter width =")
+
diff --git a/965/CH7/EX7.51/51.sci b/965/CH7/EX7.51/51.sci new file mode 100644 index 000000000..47a3a03e4 --- /dev/null +++ b/965/CH7/EX7.51/51.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("average heat transfer coefficient")
+d=22.5/1000;// m diameter of tubes
+L=5;//m length of each tube
+ti=21;//degree C
+to=29;// degree C
+tb=(ti+to)/2;// bulk temperature
+rho=996.65;// kg/m^3
+mu=0.862*10^(-3);// kg/m.s
+k=0.6079;// W/m.C
+cp=4178;// J/kg.K
+Pr=mu*cp/k;
+n=200;// number of tubes
+m=160/n;// kg/s mass flow rate per tube
+Re=4*m/(%pi*d*mu);
+Nu=0.023*Re^0.8*Pr^0.4;// mcAdams correlation
+h=Nu*k/d;
+disp("W/m^2.C",h,"Average heat transfer coefficient =")
+
diff --git a/965/CH7/EX7.52/52.sci b/965/CH7/EX7.52/52.sci new file mode 100644 index 000000000..11e0d8ee2 --- /dev/null +++ b/965/CH7/EX7.52/52.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("required tube length")
+ti=20;//degree C temperature of water
+m= 0.015;//kg/s water flow rate
+t=90;//degree C temperature of tube
+d=2.5/100;// m ID of tube
+to=70;// degree C
+tb=(ti+to)/2;// bulk temperature
+Nu=3.657;
+rho=992.3;// kg/m^3
+cp=4180;// J/kg.K
+k=0.638;// W/m.C
+v=0.613*10^(-6);// m^2/s
+h=Nu*k/d;//W/m^2.C
+disp("W/m^2.C",h,"Heat transfer coefficient =")
+Q=m*cp*(to-ti);// W
+th1=t-ti;
+th2=t-to;
+thm=(th1-th2)/log(th1/th2);
+A=Q/(h*thm);
+L=A/(%pi*d);
+disp("m",L,"Required tube legth is ")
diff --git a/965/CH7/EX7.53/53.sci b/965/CH7/EX7.53/53.sci new file mode 100644 index 000000000..96a593cf6 --- /dev/null +++ b/965/CH7/EX7.53/53.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("temperature of mixed sand")
+m=0.08/3600;// m^3/s sand feeding rate
+d=30/1000;// pipe diameter
+L=6;//m legth of pipe
+ts=100;// degree C inside temperature of pipe
+rho=1500;// kg/m^3
+k=0.3;// W/m.C
+cp=840;// J/kg.K
+ta=20;//degree C temperature of sand entering
+disp("Q=h*A*(ts-(ti+to)/2)=m*cp*(to-ti)")
+disp("h*A/2*((ts-ti)+(ts-to))= m*cp*((ts-ti)-(ts-to))")
+m=m*rho//kg/sec
+Nu=5.78;
+h=Nu*k/d;
+disp("W/m^2.C",h,"Heat transfer coefficient =")
+A=%pi*d*L;// m^2
+t=(m*cp-h*A/2)*(ts-ti)/(h*A/2+m*cp);
+to=ts-t;
+disp("degree C",to," temperature of mixed sand =")
+
diff --git a/965/CH7/EX7.54/54.sci b/965/CH7/EX7.54/54.sci new file mode 100644 index 000000000..c6193bf40 --- /dev/null +++ b/965/CH7/EX7.54/54.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("heat loss from duct")
+m=0.06;//kg/s
+d=180/1000;// m diameter
+ts=110;// degree C temperature of air entering
+L=4.5;//m length
+t=70;// degree C temperature of cooled air
+ta=5;// degree C ambient temperature
+ho=6.5;// W/m^2.C
+tb=(ts+t)/2;// bulk temperature
+rho=0.972;// kg/m^3
+cp=1009;// J/kg.C
+k=0.03127;// W/m.C
+v=22.1*10^(-6);// m^2/s
+mu=22.14*10^(-6);// kg/m.s
+Pr=0.69;
+Re=4*m/(%pi*d*mu);
+Q=m*cp*(ts-t);
+disp("W",Q,"Heat loss from duct over its 4.5 m length =")
+Nu=0.023*Re^0.8*Pr^(1/3);
+hi=k*Nu/d;
+Rth=1/hi+1/ho;// thermal resistance
+Qa=(t-ta)/Rth;// heat flux
+disp("W/m^2",Qa,"Heat flux Q/A =")
+tl=t-Qa/hi;
+disp("degree C",tl,"Surface temperature at a length of 4.5 m =")
diff --git a/965/CH7/EX7.55/55.sci b/965/CH7/EX7.55/55.sci new file mode 100644 index 000000000..0943b645f --- /dev/null +++ b/965/CH7/EX7.55/55.sci @@ -0,0 +1,35 @@ +clc;
+clear all;
+disp("number of tubes")
+ts=80;//degree C saturated steam temperature
+kb=110;// W/m.C thermal conductivity of brass
+do=1.59/100;// m OD of tubes
+ro=do/2;
+di=1.34/100;// m ID of tubes
+ri=di/2;
+tc1=20;//degree C
+tc2=40;//degree C
+mw=55000/3600;//kg/s
+U=1.4;//m/s
+kw=0.659;// W/m.C thermal conductivity of water
+rho=979.8;//kg/m^3
+cp=4180;// J/kg.K
+mu=0.4044*10^(-3);//Pa.s
+ho=10760;// W/m^2.C
+Q=mw*cp*(tc2-tc1);
+Af=mw/(rho*U);
+N=ceil(4*Af/(%pi*di^2));
+disp(N,"numebr of tubes =")
+Re=rho*U*di/mu;
+Pr=mu*cp/kw;
+Nu=0.023*Re^0.8*Pr^0.4;
+hi=kw*Nu/di;
+Uo=1/(1/ho+ro*(log(ro/ri))/(2*kb)+ro/(ri*hi));
+
+th1=ts-tc1;
+th2=ts-tc2;
+thm=(th1-th2)/log(th1/th2);
+//Ao=%pi*do*L
+Ao=Q/(Uo*thm);
+L=Ao/(%pi*do*N);
+disp("m",L,"length of each tube =")
diff --git a/965/CH7/EX7.56/56.sci b/965/CH7/EX7.56/56.sci new file mode 100644 index 000000000..2ce044ede --- /dev/null +++ b/965/CH7/EX7.56/56.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("required tube length")
+m=1.6;//m/s
+d=20/1000;//m diameter of tube
+tc1=15;// degree C temperature of enterting mercury
+tc2=35;// degree C temperature of leaving mercury
+ts=50;// degree C wall temperature
+rho=13582;//kg/m^3
+k=8.69;// W/m.C
+cp=140;// J/kg.K
+v=1.5*10^(-7);// m^2/s
+Pr=0.0248;
+Re=4*m/(%pi*d*rho*v)
+Nu=7+0.025*(Pr*Re)^0.8
+h=k*Nu/d// W/m^2.C
+tc=(tc1+tc2)/2;
+Q=m*cp*(tc2-tc1)
+As=Q/(h*(ts-tc));
+L=As/(%pi*d);
+disp("m",L,"Required tube length = ")
diff --git a/965/CH7/EX7.57/57.sci b/965/CH7/EX7.57/57.sci new file mode 100644 index 000000000..2089cb64d --- /dev/null +++ b/965/CH7/EX7.57/57.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+s=20/1000;//m side of channel
+L=2.5;//m length of channel
+U=4.5;//m/s
+tb=30;// degree C
+ts=70;// degree C
+rho=995.7;// kg/m^3
+k=0.6175;// W/m.C
+v=0.805*10^(-6);// m^2/s
+Pr=5.42;
+Prs=2.55;// Pr at 70 degree C
+Deq=4*s*s/(4*s)//m
+Re=U*Deq/v
+Nu=0.021*Re^0.8*Pr^0.43*(Pr/Prs)^0.25
+h=Nu*k/Deq;
+disp("W/m^2.C",h,"heat transfer coefficient =")
+
diff --git a/965/CH7/EX7.58/58.sci b/965/CH7/EX7.58/58.sci new file mode 100644 index 000000000..b7269ed3f --- /dev/null +++ b/965/CH7/EX7.58/58.sci @@ -0,0 +1,29 @@ +clc;
+clear all;
+disp("required tube length")
+
+U=1.2;//m/s
+ti=40;//degree C
+ts=85;// degree C
+to=75;// degree C
+x=3.5/100;//m
+y=1.5/100;//m
+//As=2*(x+y)*L
+rho=985.5;//kg/m^3
+k=0.653;//W/m.C
+v=0.517*10^(-6);// m^2/s
+cp=4190;//J/kg.K
+m=x*y*rho*U;
+Q=m*cp*(to-ti);// W
+th1=ts-ti;
+th2=ts-to;
+thm=(th1-th2)/log(th1/th2);// degree C
+Lc=2*x*y/(x+y);
+Re=Lc*U/v;
+Pr=rho*v*cp/k;
+Nu=0.023*Re^0.8*Pr^(1/3);
+h=Nu*k/Lc;
+As=Q/(h*thm);
+L=As/(2*x+2*y);
+disp("m",L,"Required tube length for raise in temperature is =")
+
diff --git a/965/CH7/EX7.6/6.sci b/965/CH7/EX7.6/6.sci new file mode 100644 index 000000000..04eaafcb9 --- /dev/null +++ b/965/CH7/EX7.6/6.sci @@ -0,0 +1,26 @@ +clc;
+clear all;
+disp("Boundary layer thickness")
+
+L=0.750;//m length of plate
+w=0.250;//m width of plate
+Re=2*10^5;// Reynold's number
+v=1*10^(-4);//m^2/s stokes kinematic viscocity
+sg=0.8;// specific gravity of oil
+U=5;//m/s velocity of oil
+x=L/2;
+Re=U*x/v;
+delta=5.*x*1000/(Re)^0.5;//mm
+disp("mm",delta,"Maximum thickness of boundary layer =")
+rho=1000;//kg/m^3
+Cfx=0.664/(Re)^0.5;
+disp(Cfx,"drag coefficient =")
+tauo=Cfx*0.5*rho*sg*U^2;
+disp("N/m^2",tauo,"Shear stress at the middle of plate =")
+ReL=U*L/v;
+Cf=1.328/(ReL)^0.5;
+A=L*w;// area of the plate
+Fd=Cf*0.5*rho*sg*U^2*A;
+disp("N",Fd,"Friction drag on the plate, Fd =")
+
+
diff --git a/965/CH7/EX7.60/60.sci b/965/CH7/EX7.60/60.sci new file mode 100644 index 000000000..dd9570aa3 --- /dev/null +++ b/965/CH7/EX7.60/60.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("average heat transfer coefficient")
+tb=27;// degree C
+d=19/1000;//m diameter of tube
+U=0.061;//m/s
+L=1.5;//m length of tube
+ts=38;//degree C
+mus=5.233*10^(-4);// Pa s
+mub=5.892*10^(-4);// Pa s
+kb=0.1591;// W/m.K
+rhob=876.6;// kg/m^3
+cpb=1757;// j/kg.K
+Prb=6.5;
+Reb=rhob*U*d/mub;
+Nu=1.86*(Reb*Prb/(L/d))^0.33*(mub/mus)^0.14;
+h=k*Nu/d;
+xv=0.05*Reb*d;// velocity depth
+xt=xv*Prb;// temperature depth
+disp("m",xv,"velocity depth =")
+disp("m",xt,"temperature depth =")
diff --git a/965/CH7/EX7.62/62.sci b/965/CH7/EX7.62/62.sci new file mode 100644 index 000000000..27fe986ee --- /dev/null +++ b/965/CH7/EX7.62/62.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("heat lost by man")
+d=0.35;// m
+h=1.65;//m
+ts=28;// degree C
+ta=12;// degree C
+U=30*1000/3600;// m/s
+tf=(ts+ta)/2; // film temperature
+k=2.59*10^(-2);// W/m.C
+v=15*10^(-6);// m^2/s
+Pr=0.707;
+Re=U*d/v;
+disp("Nu=C*Re^n*Pr^(1/3)")
+C=0.027;
+n=0.805;
+Nu=C*Re^n*Pr^(1/3);
+hs=Nu*k/d
+Q=hs*%pi*d*h*(ts-ta);
+disp("w",Q,"heat lost by man =")
diff --git a/965/CH7/EX7.63/63.sci b/965/CH7/EX7.63/63.sci new file mode 100644 index 000000000..3ab5689d0 --- /dev/null +++ b/965/CH7/EX7.63/63.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+d=0.025;//m
+ta=30;// degree C
+U=2.5;// m/s
+ts=85;// degree C
+rhoc=0.0175*10^(-6);// ohm.m^3/m
+k=0.02673;// W/m.C
+v=16*10^(-6);// m^2/s
+Re=U*d/v;
+Nu=0.22*Re^0.6;
+h=Nu*k/d;
+disp("W/m^2.C",h,"The heat transfer coefficient from the surface to the air =")
+Q=h*%pi*d*1*(ts-ta);
+R=rhoc*1/(%pi*d^2/4);
+I=(Q/R)^0.5;
+disp("amps",I,"permissible current intensity for the bus bar, I =")
diff --git a/965/CH7/EX7.64/64.sci b/965/CH7/EX7.64/64.sci new file mode 100644 index 000000000..2b70a84dc --- /dev/null +++ b/965/CH7/EX7.64/64.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("heat transfer rate")
+ta=24;//degree C
+ts=130;// degree C
+U=0.4;// m/s
+Ql=100;// W
+d=0.065;//m
+tb=(ta+ts)/2;
+k=0.03;// W/m.C
+v=2.08*10^(-5);// m^2/s
+Pr=0.697;
+Re=U*d/v;
+Nu=0.37*Re^0.6;
+h=Nu*k/d;
+Q=h*%pi*d^2*(ts-ta);
+disp("W",Q,"Heat transfer rate =")
+e=Q/Ql;
+disp("%",e*100,"the percentage of power lost due to convetion =")
diff --git a/965/CH7/EX7.65/65.sci b/965/CH7/EX7.65/65.sci new file mode 100644 index 000000000..8338de675 --- /dev/null +++ b/965/CH7/EX7.65/65.sci @@ -0,0 +1,15 @@ +clc;
+clear all;
+disp("Compare HT coefficients")
+disp("In case of turbulent tube flow, the average heat transfer coefficient is given by ")
+disp("Nu=h*d/k=0.023 *Re^0.8*Pr^0.333")
+disp("or, h = k*0.023 *Re^0.8*Pr^0.333/d")
+disp("where Re= u*d/v ")
+disp("thus h = 0.023*k/v^0.28*Pr^0.333*U^0.8/d^0.2")
+disp("i) when the flow velocity and the fluid properties remain unchanged")
+disp("h2/h1 =(d1/d2)^0.2=(1/2)^0.2 = 0.87")
+disp("this shows that heat transfer coefficient decreases to 0.87 when there is two-flod increase in the diameter of tube")
+disp("ii) when the tube diameter and fluid properties remain same")
+disp("h2/h1 =(u2/u1)^0.8 =2^0.8 =1.74 ")
+disp("this shows that the heat transfer is increases to 1.74 times when there is a two-fold increase in flow velocity")
+
diff --git a/965/CH7/EX7.66/66.sci b/965/CH7/EX7.66/66.sci new file mode 100644 index 000000000..13f948b91 --- /dev/null +++ b/965/CH7/EX7.66/66.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("heat loss from four surfaces")
+U=90*1000/3600;// m/s
+ta=50;// degree C
+l=10;//m
+w=4;//m
+h=3;//m
+ts=10;// degree C
+rho=1.165;// kg/m^3
+cp=1005;// J/kg.K
+k=.02676;// W/m.C
+v=16*10^(-6);// m^2/s
+Pr=0.701;
+Rel=U*l/v;
+Nu=0.036*Rel^0.8*Pr^0.333;
+hs=k*Nu/l;
+A=2*(w+h)*l;
+Ql=hs*A*(ta-ts);//W
+Q=Ql/1000;// kQ
+disp("W",Q,"Heat loss from surfaces =")
+cc=Q*3600/14000;
+disp("TR",cc,"Cooling capacity required =")
+Cf=0.072/(Rel)^0.2;
+Fd=Cf*0.5*rho*A*U^2;
+P=Fd*U/1000;
+disp("kW",P,"Power required to overcome the resistance =")
diff --git a/965/CH7/EX7.67/67.sci b/965/CH7/EX7.67/67.sci new file mode 100644 index 000000000..f18799919 --- /dev/null +++ b/965/CH7/EX7.67/67.sci @@ -0,0 +1,36 @@ +clc;
+clear all;
+disp("temperature of cheese leaving")
+m=800;//kg/h
+D=100/1000;//m
+L=1.75;//m
+
+ts=95;//degree C
+t1=15;//degree C
+rho=1150;//kg/m^3
+cp=2750;//J/kg.C
+mu=22.5;//kg/m.s
+k=0.421;//W/(m.C)
+
+A=3.1416*(D^2)/4;
+U=(m/3600)/(rho*A);// m/s
+Re=(m/3600)*D/(A*mu);
+Pr=mu*cp/k;
+X=(D/L)*Re*Pr;
+X
+
+Nu=3.65+0.067*X/(1+0.04*X^(1/3))
+h=k*Nu/D;
+disp("W/m^2.C",h,"heat transfer coefficient h =")
+
+//tb=(t1+t2)/2;
+//t2=t1+h*A*(ts-tb)/(m*cp);
+//611.11*(t2-15)=62.4*(175-t2)
+//t2*(611.11+62.4)=175*62.4+15*611.11
+t2=(175*62.4+15*611.11)/(611.11+62.4)
+disp("degree C",t2,"temperature of cheese leaving heated section t =")
+
+Q=m*cp*(t2-t1)/3600;
+
+disp ("W",Q,"Rate of heat transfer from tube to cheese =")
+
diff --git a/965/CH7/EX7.68/68.sci b/965/CH7/EX7.68/68.sci new file mode 100644 index 000000000..2dd8f70b9 --- /dev/null +++ b/965/CH7/EX7.68/68.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+to=25;//degree C
+ti=130;//degree C
+U=16.5;// m/s
+v=15.53*10^(-6);//m^2/s
+Q=100;//W
+D=20/1000;//m
+L=120/1000;//m
+dis=0.12;// power loss
+As=3.1416*D*L;
+h=Q*(1-dis)/(As*(ti-to));
+disp("W/m^2.C",h,"heat transfer coefficient h =")
+Re=U*D/v;
+Pr=0.702;
+Prs=0.685;
+Nu=0.26*(Re^0.6)*(Pr^0.36)*(Pr/Prs)^0.25;
+disp (Nu,"Nusselt number Nu =")
+h=Nu*k/D;
+disp("W/m^2.C",h,"heat transfer coefficient ")
+
diff --git a/965/CH7/EX7.7/7.sci b/965/CH7/EX7.7/7.sci new file mode 100644 index 000000000..2e980919f --- /dev/null +++ b/965/CH7/EX7.7/7.sci @@ -0,0 +1,28 @@ +clc;
+clear all;
+disp("Boundary layer thickness")
+
+x=1.2;//m distance from the leading edge of plate
+v=15.4*10^(-6);//m^2/s kinematic viscocity
+U=2.8;//m/s velocity of air
+
+
+Re=U*x/v;// Reynold's number
+disp("Blasius solution")
+delta1=5*x*1000/(Re)^0.5;//mm
+disp("mm",delta1,"Maximum thickness of boundary layer =")
+
+Cfx1=0.664/(Re)^0.5;
+disp(Cfx1,"drag coefficient =")
+
+disp("Approximate solution")
+delta2=4.64*x*1000/(Re)^0.5;//mm
+disp("mm",delta2,"Maximum thickness of boundary layer =")
+Cfx2=0.646/(Re)^0.5;
+disp(Cfx2,"drag coefficient =")
+
+e1=(1-delta2/delta1)*100;
+disp("%",e1,"Deviation for delta =")
+
+e2=(1-Cfx2/Cfx1)*100;
+disp("%",e2,"Deviation for Drag coefficient =")
diff --git a/965/CH7/EX7.8/8.sci b/965/CH7/EX7.8/8.sci new file mode 100644 index 000000000..9ae514d95 --- /dev/null +++ b/965/CH7/EX7.8/8.sci @@ -0,0 +1,27 @@ +clc;
+clear all;
+disp("Laminar flow over plate")
+
+L=5;//m plate length
+w=2.5;//m plate width
+
+x=1.2;//m distance from the leading edge of plate
+v=15.4*10^(-6);//m^2/s kinematic viscocity
+U=4;//m/s velocity of air
+rho=1.208;//kg/m^3 density of air
+v=1.47*10^(-5);//m^2/s kinematic viscosity of air
+
+Re=5*10^5;// Reynold's number
+x=Re*v/U;// length of plste over which boundary layer is laminar
+disp("m",x,"length of plste over which boundary layer is laminar =")
+delta=5*x*1000/(Re)^0.5;//mm
+disp("mm",delta,"thickness of boundary layer =")
+Cfx=0.664/(Re)^0.5;
+disp(Cfx,"drag coefficient =")
+tau=Cfx*0.5*rho*U^2;// shear stress
+disp("N/m^2",tau,"Shear stress =")
+Cf=1.328/(Re)^0.5;
+A=x*w;//m^2 area of plate
+Fd=2*Cf*0.5*rho*A*U^2;
+disp("N",Fd,"Total drag force on both sides of plate, =")
+
diff --git a/965/CH7/EX7.9/9.sci b/965/CH7/EX7.9/9.sci new file mode 100644 index 000000000..0803b6a6d --- /dev/null +++ b/965/CH7/EX7.9/9.sci @@ -0,0 +1,23 @@ +clc;
+clear all;
+disp("Laminar flow over plate")
+
+L=0.5;//m plate length
+w=0.6;//m plate width
+U=4;//m/s velocity of air
+rho=1.24;//kg/m^3 density of air
+v=1.5*10^(-5);//m^2/s kinematic viscosity of air
+
+ReL=U*L/v;// Reynold's number
+delta=4.795*L*1000/(Re)^0.5;//mm
+disp("mm",delta,"Boundary layer thickness =")
+x=0.25;
+Re=U*x/v;// Reynold's number
+Cfx=0.654/(Re)^0.5;
+disp(Cfx,"drag coefficient =")
+tau=Cfx*0.5*rho*U^2;// shear stress
+disp("N/m^2",tau,"Shear stress at 250 mm from leading edge, =")
+Cf=1.31/(ReL)^0.5;
+A=L*w;//m^2 area of plate
+Fd=Cf*0.5*rho*A*U^2;
+disp("N",Fd,"drag force on one side of plate, =")
diff --git a/965/CH9/EX9.1/1.sci b/965/CH9/EX9.1/1.sci new file mode 100644 index 000000000..0081c4219 --- /dev/null +++ b/965/CH9/EX9.1/1.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("The heat flux")
+d=1.2/1000;//m diameter of wire
+L=0.2;//m length of wire
+p=7;// bar
+I=135;// Amp
+V=2.18;//V
+ts=200;// degree C
+A=%pi*d*L;//m^2
+tsat=164.97;// degree C corresponding to 7 bar
+Q=V*I;//W
+flux=Q/A;// W/m^2 heat flux
+disp("W/m^2",flux,"the heat flux =")
+h=flux/(ts-tsat);
+disp("W/m^2.C",h,"boiling heat transfer coefficient =")
diff --git a/965/CH9/EX9.10/10.sci b/965/CH9/EX9.10/10.sci new file mode 100644 index 000000000..d27c82347 --- /dev/null +++ b/965/CH9/EX9.10/10.sci @@ -0,0 +1,17 @@ +clc;
+clear all;
+disp("Thickness of film")
+L=0.4;//m
+tsat=100;// degree C
+hfg=2257*1000;// J/kg
+ts=90;// degree C
+rhol=965.3;// kg/m^3
+k=0.68;// W/m.C
+mu=3.153*10^(-4);// Ns/m^2
+g=9.81;// m/s^2
+del=(4*k*mu*(tsat-ts)*L/(g*hfg*rhol^2))^0.25;// m
+disp("mm",del*1000,"Thickness of film at bottom edge of the fin ")
+h=4*k/(3*del);
+disp("W/m^2.C",h,"Overall heat transfer coefficient ")
+Q=1.2*h*(tsat-ts)*L;
+disp("W",Q,"heat transfer rate wuth McAdams correction =")
diff --git a/965/CH9/EX9.11/11.sci b/965/CH9/EX9.11/11.sci new file mode 100644 index 000000000..8de29035c --- /dev/null +++ b/965/CH9/EX9.11/11.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("heat transfer rate")
+L=0.5;//m
+b=1;//m
+ts=30;// degree C
+rho=980.3;//kg/m^3
+k=66.4*10^(-2);//W/m.C
+mu=434*10^(-6);// kg/ms
+hfg=2257*10^3;// J/kg
+g=9.81;// m/s
+tsat=100;// degree C
+ts=30;// degree C
+h=0.943*(rho^2*k^3*g*hfg/(mu*L*(tsat-ts)))^0.25;
+Q=h*L*b*(tsat-ts)*3600/1000;
+disp("kJ/h",Q,"rate of heat transfer per metre width, Q =")
+m=Q*1000/hfg;
+disp("kg/h",m,"The condensate rate per metre width =")
diff --git a/965/CH9/EX9.12/12.sci b/965/CH9/EX9.12/12.sci new file mode 100644 index 000000000..c47264bcb --- /dev/null +++ b/965/CH9/EX9.12/12.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("film thickness at bottom")
+L=0.35;//m
+b=.42;//m
+ts=40;// degree C
+rho=977.8;//kg/m^3
+k=0.667;//W/m.C
+mu=400*10^(-6);// kg/ms
+hfg=2257*10^3;// J/kg
+g=9.81;// m/s
+tsat=100;// degree C
+del=(4*k*mu*(tsat-ts)*L/(g*rho^2*hfg))^0.25;
+disp("mm",del*1000,"The film thickness at the bottom of plate =")
+u=rho*g*del^2/(2*mu);
+disp("m/s",u,"Maximum velocity at the bottom of plate =")
+h=0.943*(rho^2*k^3*g*hfg/(mu*L*(tsat-ts)))^0.25;
+Q=h*L*b*(tsat-ts);
+disp("kW",Q/1000,"rate of heat transfer per metre width, Q =")
+
diff --git a/965/CH9/EX9.13/13.sci b/965/CH9/EX9.13/13.sci new file mode 100644 index 000000000..21c28b680 --- /dev/null +++ b/965/CH9/EX9.13/13.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("film thickness at bottom")
+L=0.6;//m
+b=1;//m
+ts=60;// degree C
+rhol=971.8;//kg/m^3
+k=67.413*10^(-2);//W/m.C
+mu=355.3*10^(-6);// kg/ms
+hfg=2257*10^3;// J/kg
+rhov=0.596;//kg/m^3
+g=9.81;// m/s
+tsat=100;// degree C
+del=(4*k*mu*(tsat-ts)*L/(g*rhol*(rhol-rhov)*hfg))^0.25;
+disp("mm",del*1000,"The film thickness at the bottom of plate =")
+h=4*k/(3*del);
+h=1.2*h;
+disp("W/m^2.C",h,"The overall heat transfer coefficient =")
+Q=h*L*b*(tsat-ts);
+disp("kW",Q/1000,"rate of heat transfer per metre width, Q =")
+m=Q/hfg;//kg/hr
+disp("kg/hr",m*3600,"Condensate flow rate =")
+Re=4*m/(mu*b);
+disp(Re,"Re =")
+
diff --git a/965/CH9/EX9.14/14.sci b/965/CH9/EX9.14/14.sci new file mode 100644 index 000000000..487b4324e --- /dev/null +++ b/965/CH9/EX9.14/14.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("heat transfer rate")
+d=0.06;//m diameter
+L=1.2;//m
+ts=50;// degree C
+tsat=100;//degree C
+rhol=975;//kg/m^3
+mu=375*10^(-6);// Ns/m^2
+k=0.67;// W/m.C
+rhov=0.596;// kg/m^3
+hfg=2257*10^3;// J/kg
+g=9.81;//m/s
+h=1.13*(rhol*(rhol-rhov)*k^3*g*hfg/(mu*L*(tsat-ts)))^0.25;
+Q=h*(%pi*d*L)*(tsat-ts);
+disp("kW",Q/1000,"The rate of heat transfer =")
+m=Q/hfg;//kg/s
+disp("kg/h",m*3600,"rate of condensation of steam =")
+Re=4*m/(%pi*d*mu);
+disp(Re,"Re =")
diff --git a/965/CH9/EX9.15/15.sci b/965/CH9/EX9.15/15.sci new file mode 100644 index 000000000..a91e32d7d --- /dev/null +++ b/965/CH9/EX9.15/15.sci @@ -0,0 +1,18 @@ +clc;
+clear all;
+disp("rate of condensate formation")
+d=0.02;//m diameter
+ts=84;// degree C
+tsat=100;//degree C
+rhol=963.4;//kg/m^3
+mu=306*10^(-6);// Ns/m^2
+k=0.677;// W/m.C
+rhov=0.596;// kg/m^3
+hfg=2257*10^3;// J/kg
+g=9.81;//m/s
+h=0.725*(rhol*(rhol-rhov)*k^3*g*hfg/(mu*d*(tsat-ts)))^0.25;
+Ql=h*(%pi*d)*(tsat-ts);
+disp("W/m",Ql,"The rate of heat transfer =")
+ml=Ql/hfg;//kg/s
+disp("kg/h",ml*3600,"rate of condensation of steam =")
+
diff --git a/965/CH9/EX9.16/16.sci b/965/CH9/EX9.16/16.sci new file mode 100644 index 000000000..c680f5f01 --- /dev/null +++ b/965/CH9/EX9.16/16.sci @@ -0,0 +1,19 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+n=625;// number of tubes
+N=n^0.5;
+d=0.006;//m diameter
+ts=25;// degree C
+tsat=54;//degree C
+rhol=992;//kg/m^3
+mu=663*10^(-6);// Ns/m^2
+k=0.631;// W/m.C
+rhov=0.098;// kg/m^3
+hfg=2373*10^3;// J/kg
+g=9.81;//m/s
+h=0.725*(rhol*(rhol-rhov)*k^3*g*hfg/(N*mu*d*(tsat-ts)))^0.25;
+disp("W/m^2.C",h,"The heat transfer coefficient =")
+ml=h*%pi*d*(tsat-ts)/hfg;//kg/s
+m=n*ml;
+disp("kg/s.m",m,"rate of condensation of steam for complete array =")
diff --git a/965/CH9/EX9.17/17.sci b/965/CH9/EX9.17/17.sci new file mode 100644 index 000000000..c6112b5a0 --- /dev/null +++ b/965/CH9/EX9.17/17.sci @@ -0,0 +1,32 @@ +clc;
+clear all;
+disp("square plate")
+x=0.4;//m
+L=0.75;//mm
+ts=28;// degree C
+rhol=993.95;//kg/m^3
+k=62.53*10^(-2);//W/m.C
+mu=728.15*10^(-6);// kg/ms
+hfg=2402*10^3;// J/kg
+rhov=0.561;//kg/m^3
+g=9.81;// m/s
+tsat=42;// degree C
+delx=(4*k*mu*(tsat-ts)*x/(g*rhol*(rhol-rhov)*hfg))^0.25;
+disp("mm",delx*1000,"The film thickness at the bottom of plate =")
+hx=k/delx;
+disp("W/m^2.C",hx,"heat transfer coefficient =")
+delL=(4*k*mu*(tsat-ts)*L/(g*rhol*(rhol-rhov)*hfg))^0.25;
+disp("mm",delL*1000,"The film thickness at the bottom of plate =")
+hL=4*k/(3*delL);
+disp("W/m^2.C",hL,"heat transfer coefficient =")
+h=1.2*hL;
+disp("W/m^2.C",h,"The overall heat transfer coefficient =")
+Q=h*L*L*(tsat-ts);
+disp("kW",Q/1000,"rate of heat transfer per metre width, Q =")
+m=Q/hfg;//kg/hr
+disp("kg/hr",m*3600,"Condensate flow rate =")
+hinc=h*(sin(%pi*25/180))^0.25;
+disp("W/m^2.C",hinc,"heat transfer coefficient when the plate is inclined 25 degree with the horizontal")
+Re=4*m/(mu*L);
+disp(Re,"Re =")
+
diff --git a/965/CH9/EX9.18/18.sci b/965/CH9/EX9.18/18.sci new file mode 100644 index 000000000..2a9409f45 --- /dev/null +++ b/965/CH9/EX9.18/18.sci @@ -0,0 +1,22 @@ +clc;
+clear all;
+disp("heat transfer rate")
+L=3.2;//m
+d=0.006;//m diameter
+ts=54;// degree C
+tsat=100;//degree C
+rhol=973.7;//kg/m^3
+mu=365*10^(-6);// Ns/m^2
+k=0.668;// W/m.C
+rhov=0.596;// kg/m^3
+hfg=2257*10^3;// J/kg
+g=9.81;//m/s
+disp("h=0.0077*(rhol*(rhol-rhov)*k^2*g/(mu^2))^0.333*Re^0.4")
+disp("Eliminating h from euqation we get the condition that the flow will be turbulent if ")
+disp("0.00296*((rhol*(rhol-rhov)*k^3*g*(tsat-ts)^3*L^3/(mu^5*hfg^3))^(5/9)>1800")
+x=0.00296*(rhol*(rhol-rhov)*k^3*g*(tsat-ts)^3*L^3/(mu^5*hfg^3))^(5/9);
+if(x>1800)
+Re=x
+h=0.0077*(rhol*(rhol-rhov)*k^2*g/(mu^2))^0.333*Re^0.4
+Q=h*L*1*(tsat-ts);
+disp("kW/m",Q/1000,"hear transfer rate per unit width =")
diff --git a/965/CH9/EX9.19/19.sci b/965/CH9/EX9.19/19.sci new file mode 100644 index 000000000..4ac2a64b2 --- /dev/null +++ b/965/CH9/EX9.19/19.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("heat transfer coefficient")
+m=1800/3600;// kg/s
+d=8/1000;//m
+ts=24;// degree C
+tsat=45.8;// degree C
+rhov=0.0676;// kg/m^3
+hf=2393*10^(3);// J/kg
+rhol=993.95;// kg/m^3
+k=62.53*10^(-2);// W/m.C
+mu=728.15*10^(-6);// kg/m.s
+n=400;
+N=n^0.5;
+h=0.725*(rhol*(rhol-rhov)*k^3*g*hfg/(N*mul*(tsat-ts)*d));
+disp("W/m^2.C",h,"Average heat transfer coefficient =")
+Q=m*hfg;
+L=Q/(%pi*d*h*(tsat-ts));
+disp("m",L,"Length of each tube, assuming single pass =")
+
diff --git a/965/CH9/EX9.2/2.sci b/965/CH9/EX9.2/2.sci new file mode 100644 index 000000000..bd02d43dc --- /dev/null +++ b/965/CH9/EX9.2/2.sci @@ -0,0 +1,13 @@ +clc;
+clear all;
+disp("the heat flux")
+d=1.25/1000;// m diameter of wire
+L=0.25;//m length of wire
+V=18;// V
+I=45;// amp
+Q=V*I;// W
+A=%pi*d*L;//m^2
+q=Q/A;// W/m^2
+disp("W/m^2",q,"the heat flux =")
+delTe=((1.58*q^0.75)/5.62)^(1/3);// degree C
+disp("degree C",delTe,"The excess temperature")
diff --git a/965/CH9/EX9.20/20.sci b/965/CH9/EX9.20/20.sci new file mode 100644 index 000000000..ba6b28a7d --- /dev/null +++ b/965/CH9/EX9.20/20.sci @@ -0,0 +1,28 @@ +clc;
+clear all;
+disp("cylindrical drum")
+d=0.35;// m diameter
+ts=80;// degree C
+rhol=956.4;//kg/m^3
+k=68.23*10^(-2);//W/m.C
+mu=283*10^(-6);// kg/ms
+hfg=2201.6*10^3;// J/kg
+vg=0.885;// m^3/kg
+rhov=1/vg;//kg/m^3
+g=9.81;// m/s
+m=70/3600;// kg/s
+tsat=120.2;// degree C
+disp("delL=(4*k*mu*(tsat-ts)*L/(g*rhol*(rhol-rhov)*hfg))^0.25")
+a=(4*k*mu*(tsat-ts)/(g*rhol*(rhol-rhov)*hfg))^0.25
+disp("delL=a*L^0.25")
+disp("hL=4*k/(3*delL)")
+b=1.2*4*k/(3*a)//hl=b*L^(-0.25)
+//Q=h*%pi*d*L*(tsat-ts)
+Q=m*hfg;
+L=(Q/(b*%pi*d*(tsat-ts)))^(4/3);
+disp("mm",L*1000,"length of drum =")
+delL=(4*k*mu*(tsat-ts)*L/(g*rhol*(rhol-rhov)*hfg))^0.25;
+disp("mm",delL,"Thickness of condensate layer =")
+Re=4*m/(mu*d);
+disp(Re,"Re =")
+
diff --git a/965/CH9/EX9.3/3.sci b/965/CH9/EX9.3/3.sci new file mode 100644 index 000000000..2168fe212 --- /dev/null +++ b/965/CH9/EX9.3/3.sci @@ -0,0 +1,16 @@ +clc;
+clear all;
+disp("Volatge at burnout point")
+d=0.001;//m diameter of wire
+I=190;//amp
+L=0.4;//m length of wire
+rhol=958.4;//kg/m^3
+rhov=0.5955;//kg/m^3
+hfg=2257*10^3;//J/kg
+s=58.9*10^(-3);// N/m
+g=9.81;//m/s^2
+qsc=0.18*rhov^0.5*hfg*(g*s*(rhol-rhov))^0.25;// at burnout i.e. points of critical flux
+A=%pi*d*L;
+Q=A*qsc;
+Vb=Q/I;// V
+disp("V",Vb,"Voltage at burnout point =")
diff --git a/965/CH9/EX9.4/4.sci b/965/CH9/EX9.4/4.sci new file mode 100644 index 000000000..95c81a377 --- /dev/null +++ b/965/CH9/EX9.4/4.sci @@ -0,0 +1,20 @@ +clc;
+clear all;
+disp("temperature at the bottom")
+m=25/3600;//kg/s
+d=0.28;// m diameter of copper pan
+tsat=100;// degree C
+rhol=958.4;// kg/m^3
+rhov=0.5955;// kg/m^3
+cpl=4220;//J/kg.K
+mul=279*10^(-6);//Pa.s
+Prl=1.75;
+hfg=2257*1000;// J/kg
+s=58.9*10^(-3);// N/m
+n=1;// for water
+A=%pi*d^2/4;// m^2
+qs=m*hfg/A;// W/m^2
+csl=0.013;
+te=(qs/(mul*hfg)*(s/(g*(rhol-rhov)))^0.5)^0.333*(csl*hfg*Prl/cpl);
+ts=tsat+te;
+disp("degree C",ts,"The temperature of the bottom surface of the plan")
diff --git a/965/CH9/EX9.5/5.sci b/965/CH9/EX9.5/5.sci new file mode 100644 index 000000000..8f934ce98 --- /dev/null +++ b/965/CH9/EX9.5/5.sci @@ -0,0 +1,25 @@ +clc;
+clear all;
+disp("Power of burner")
+d=0.35;// diameter of pan
+ts=115;// degree C
+rhol=958.4;// kg/m^3
+rhov=0.5955;// kg/m^3
+cpl=4220;// J/kg.K
+mul=279*10^(-6);// Ns/m^2
+Prl=1.75;
+hfg=2257*10^3;// J/kg
+s=58.9*10^(-3);// N/m
+te=15;// degree C excess temperature
+g=9.81;//m/s^2
+n=1;
+csl=0.013;
+qs=mul*hfg*(g*(rhol-rhov)/s)^0.5*(cpl*te/(csl*hfg*Prl^n))^3// W/m^2
+Q=qs*%pi*d^2/4;//
+disp("W",Q,"Power of burner to maintain boiling =")
+mw=Q/hfg*3600;// kg/hr
+disp("kg/hr",mw,"Rate of evaporation =")
+qsc=0.18*(rhov)^0.5*hfg*(g*s*(rhol-rhov))^0.25;// W/m^2
+disp("W/m^2",qsc,"Critical heat flux =")
+
+
diff --git a/965/CH9/EX9.6/6.sci b/965/CH9/EX9.6/6.sci new file mode 100644 index 000000000..bfd1f4b3d --- /dev/null +++ b/965/CH9/EX9.6/6.sci @@ -0,0 +1,21 @@ +clc;
+clear all;
+disp("power dissipation/length")
+d=0.01;//m
+e=0.92;
+ts=260;// degree C
+rhol=958.4;// kg/m^3
+hfg=2257*10^3;//J/kg
+rhov=4.807;// k/m^3
+cpv=2.56*10^3;// J/kg.K
+k=0.0331;// W/m.K
+muv=14.85*10^(-6);// Ns/m^2
+mug=muv;;
+g=9.81;//m/s
+ta=100;// degree C
+te=ts-ta;// excess temperature
+hconv=0.65*(k^3*rhov*(rhol-rhov)*g*(hfg+0.4*cpv*te)/(muv*d*te))^0.25;
+hrad=5.67*10^(-8)*e*(ts^4-ta^4)/(ts-ta);
+h=hconv+3*hrad/4;
+Q=h*%pi*d*(ts-ta);//
+disp("W",Q,"power dissipation per unit length for the heater =")
diff --git a/965/CH9/EX9.7/7.sci b/965/CH9/EX9.7/7.sci new file mode 100644 index 000000000..3a6fc3bc1 --- /dev/null +++ b/965/CH9/EX9.7/7.sci @@ -0,0 +1,15 @@ +clc;
+clear all;
+disp("different types of processes for condensation of capours on a solid surface")
+disp("there are two types of methods for condensation")
+disp("filmwise - in which condensation wets the surface forming a continuous film whic corners the entire surface")
+disp("dropwise - in which vapour condenses into small droplets of various sizes which fall down the surface in a random fashion")
+disp("filmwise - generally occurs on clean uncontaminated surfaces.")
+disp("in this type of condensation the film covering the entire surface grows in thickness as it moves down the surface by gravity.")
+disp("There exists a thermal gradient in the film and so it acts as a resistance to heat transfer")
+disp("Although a dropwise condensation would be preferred to filmwise condensation yet it is extremely difficult to achieve and maintain")
+disp("This is because most surface become wetted after being exposed to condensing vapours over a period of time. ")
+disp("Dropwise condensation can be obtained under controlled conditions with the help of certain additives to the condensate and various surface coatings,")
+disp("But its commercial viability has not yet been proved")
+disp("For this reason the condensaing equipments in use are designed on the basis of filmwise condensation.")
+
diff --git a/965/CH9/EX9.8/8.sci b/965/CH9/EX9.8/8.sci new file mode 100644 index 000000000..ffc5e3204 --- /dev/null +++ b/965/CH9/EX9.8/8.sci @@ -0,0 +1,16 @@ +clc
+clear all;
+disp("local transfer coefficient")
+tsat=90;// degree C
+ta=70;// degree C
+L=1.5;//m
+d=2.5;//m outer diameter;//
+rhol=974;//kg/m^3
+k=0.668;// W/m.K
+mul=0.335*10^(-3);//kg/m.s
+hfg=2309*1000;//J/kg
+g=9.81;// m/s^2
+hL=((rhol^2)*(k^3)*g*hfg/(4*mul*L*(tsat-ta)))^0.25;
+disp("W/m^2.C",hL,"Local heat transfer coefficient =")
+h=4*hL/3;//
+disp("W/m^2.C",h,"average heat transfer coefficient =")
diff --git a/965/CH9/EX9.9/9.sci b/965/CH9/EX9.9/9.sci new file mode 100644 index 000000000..bc3954ca6 --- /dev/null +++ b/965/CH9/EX9.9/9.sci @@ -0,0 +1,20 @@ +clc
+clear all;
+disp("average heat transfer coefficient")
+ts=120;// degree C
+d=2/100;//m
+L=0.2;//m
+ta=119;// degree C
+psat=1.985;// bar
+rhow=943;//kg/m^3
+hfg=2202.2*1000;//J/kg
+kw=0.686;// W/m.K
+mu=273.3*10^(-6);// Ns/m^2
+
+g=9.81;//m/s^2
+del=(4*kw*mu*(ts-ta)*L/(rhol^2*g*hfg))^0.25;//
+hL=k/del;
+disp("mm",del*1000,"Thickness of condensate film =")
+h=4*hL/3;
+disp("W/m^2.C",h,"Average heat transfer coefficient =")
+
|