From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001 From: priyanka Date: Wed, 24 Jun 2015 15:03:17 +0530 Subject: initial commit / add all books --- 581/CH8/EX8.1/Example8_1.sce | 27 +++++++++++++++++++++++++++ 581/CH8/EX8.3/Example8_3.sce | 26 ++++++++++++++++++++++++++ 581/CH8/EX8.4/Example8_4.sce | 33 +++++++++++++++++++++++++++++++++ 581/CH8/EX8.5/Example8_5.sce | 34 ++++++++++++++++++++++++++++++++++ 581/CH8/EX8.6/Example8_6.sce | 31 +++++++++++++++++++++++++++++++ 5 files changed, 151 insertions(+) create mode 100755 581/CH8/EX8.1/Example8_1.sce create mode 100755 581/CH8/EX8.3/Example8_3.sce create mode 100755 581/CH8/EX8.4/Example8_4.sce create mode 100755 581/CH8/EX8.5/Example8_5.sce create mode 100755 581/CH8/EX8.6/Example8_6.sce (limited to '581/CH8') diff --git a/581/CH8/EX8.1/Example8_1.sce b/581/CH8/EX8.1/Example8_1.sce new file mode 100755 index 000000000..72cf1d2ea --- /dev/null +++ b/581/CH8/EX8.1/Example8_1.sce @@ -0,0 +1,27 @@ + +clear; +clc; + +printf("\t Example 8.1\n"); + +T1=313; //fluid temp.,K +T2=287; //air temp.,K +H=0.4; //height of sides,m +Pr=0.711; //prandtl no. + + + b=1/T2; // b=1/v*d(R*T/p)/dt=1/To characterisation constant of thermal expansion of solid, K^-1 + RaL=9.8*b*(T1-T2)*H^3/((1.566*10^-5)*(2.203*10^-5)); //Rayleigh no. + + Nu=0.678*RaL^(0.25)*(Pr/(0.952+Pr))^(1/4); // nusselt no. + h=Nu*0.02614/H // average heat transfer coefficient, W/m^2/K + + q=h*(T1-T2) // average heat transfer,W/m^2 + c=3.936*((0.952+Pr)/Pr^2)^(1/4)*(1/(RaL/Pr)^0.25); //boundary layer thickness.,m + printf("\t average heat transfer coefficient is : %.2f W/m^2/K\n",h); + printf("\t average heat transfer is : %.1f W/m^2\n",q); + printf("\t boundary layer thickness is : %.3f m\n",c); + + printf("\t thus the BL thickness at the end of the plate is only 4 percent of the height, or 1.72 cm thick.this is thicker thsan typical forced convection BL but it is still reasonably thin.") + + //end \ No newline at end of file diff --git a/581/CH8/EX8.3/Example8_3.sce b/581/CH8/EX8.3/Example8_3.sce new file mode 100755 index 000000000..6afb5398a --- /dev/null +++ b/581/CH8/EX8.3/Example8_3.sce @@ -0,0 +1,26 @@ + +clear; +clc; + +printf("\t Example 8.3\n"); + +T1=323; //wall temp.,K +T2=293; //air temp.,K +H=0.3; //height of wall, m +v1=16.45*10^-6; // molecular diffusivity, m^2/s +b=1/T2; // b=1/v*d(R*T/p)/dt=1/To characterisation constant of thermal expansion of solid, K^-1 +v2=2.318*10^-5; //molecular diffusivity, m^2/s +Pr=0.71; //prandtl no. + + Ral=9.8*b*(T1-T2)*H^3/((1.566*10^-5)*(2.203*10^-5)); // Rayleigh no. + Nu=0.678*Ral^(0.25)*(Pr/(0.952+Pr))^(1/4); // nusselt no. + h=Nu*0.0267/H // average heat transfer coefficient, W/m^2/K + + Nu1=0.68+0.67*((Ral)^(1/4)/(1+(0.492/Pr)^(9/16))^(4/9)); //churchill correlation + + h1=Nu1*(0.0267/0.3)-.11; //average heat transfer coefficient, W/m^2/K + + +printf("\t correlation average heat transfer coefficient is :%.2f W/m^2/K\n",h1) +printf("\t the prediction is therefore within 5 percent of corelation .we should use the latter result in preference to the theoritical one, although the difference is slight.") + //end \ No newline at end of file diff --git a/581/CH8/EX8.4/Example8_4.sce b/581/CH8/EX8.4/Example8_4.sce new file mode 100755 index 000000000..33dd6ed59 --- /dev/null +++ b/581/CH8/EX8.4/Example8_4.sce @@ -0,0 +1,33 @@ + +clear; +clc; + +printf("\t Example 8.4\n"); + +T1=400; //hot oil temp.,K +D=0.005; //diameter of line carrying oil, m +T2=300; //temp. of air around the tube,K +Tav=350; //average BI temp.,K + +//we evaluate properties at this temp. and write g as ge*(g-level), where ge is g at the earth surface and the g-level is the fraction of ge in the space vehicle. +b=1/T2; // b=1/v*d(R*T/p)/dt=1/To characterisation constant of thermal expansion of solid, K^-1 + +v1=2.062*10^-5; // molecular diffusivity, m^2/s +v2=2.92*10^-5; //molecular diffusivity, m^2/s +Pr=0.706; //prandtl no. + +g=[10^-6 10^-5 10^-4 10^-2]; +i=1; +while(i<5) +Ral=(9.8*b*((T1-T2))*(D^(3))/(v1*v2))*g(i); // Rayleigh no. +Nu(i)=(0.6+0.387*(Ral/(1+(0.559/Pr)^(9/16))^(16/9))^(1/6))^2; +//Nu(i)=(0.6+0.387*((Ral)/(1+(0.559/Pr)^(9/16))^(16/9))^1/6)^2; //churchill correlation. +printf("\t Nusselt no. are : %.3f\n",Nu(i)); +h(i)=Nu(i)*0.0297/D; // convective heat transfer coefficient,W/(m^2*K) +printf("\t convective heat transfer coefficient are : %.2fW/(m^2*K)\n",h(i)); +Q(i)=%pi*D*h(i)*(T1-T2); //heat transfer,W/m +printf("\t heat transfer is :%.2fW/m of tube\n",Q(i)); +i=i+1; +end + +//end \ No newline at end of file diff --git a/581/CH8/EX8.5/Example8_5.sce b/581/CH8/EX8.5/Example8_5.sce new file mode 100755 index 000000000..94f4e9997 --- /dev/null +++ b/581/CH8/EX8.5/Example8_5.sce @@ -0,0 +1,34 @@ + +clear ; +clc; + +printf("\t Example 8.5\n"); + +T2=300; //air temp.,K +P=15; //delivered power,W +D=0.17; //diameter of heater,m +v1=1.566*10^-5; // molecular diffusivity, m^2/s +b=1/T2; // b=1/v*d(R*T/p)/dt=1/To characterisation constant of thermal expansion of solid, K^-1 +Pr=0.71; //prandtl no. +v2=2.203*10^-5; //molecular diffusivity, m^2/s +v3=3.231*10^-5; //molecular diffusivity at a b except at 365 K., m^2/s +v4=2.277*10^-5; //molecular diffusivity at a b except at 365 K., m^2/s +k1=0.02614; //thermal conductivity +k2=0.0314; //thermal conductivity + +//we have no formula for this situation, so the problem calls for some guesswork.following the lead of churchill and chau, we replace RaD with RaD1/NuD in eq. +//(NuD)^(6/5)=0.82*(RaD1)^(1/5)*Pr^0.034 + +delT=1.18*P/(3.14*D^(2)/4)*(D/k1)/((9.8*b*661*D^(4)/(0.02164*v1*v2))^(1/6)*Pr^(0.028)); + +//in the preceding computation, all the properties were evaluated at T2.mow we must return the calculation,reevaluating all properties except b at 365 K. + +delTc=1.18*661*(D/k2)/((9.8*b*661*D^(4)/(k2*v3*v4))^(1/6)*(0.99)); + +TS=T2+delTc; +TS1=TS-271.54 + +printf("\t average surface temp. is :%.0f K\n",TS1); + +printf("\t that is rather hot.obviously, the cooling process is quite ineffective in this case.") +//end diff --git a/581/CH8/EX8.6/Example8_6.sce b/581/CH8/EX8.6/Example8_6.sce new file mode 100755 index 000000000..52a9415fe --- /dev/null +++ b/581/CH8/EX8.6/Example8_6.sce @@ -0,0 +1,31 @@ + +clear; +clc; + +printf("\t Example 8.6\n"); + +T2=363; // temp. of strip,K +T1=373; //saturated temp.,K +H=0.3; // height of strip,m +Pr=1.86; //prandtl no. +Hfg=2257; //latent heat. kj/kg +ja=4.211*10/Hfg; //jakob no. +a1=961.9; //density of water,kg/m^3 +a2=0.6; //density of air,kg/m^3 +k=0.677; //thermal conductivity,W/(m*K) + +Hfg1=Hfg*(1+(0.683-0.228/Pr)*ja); //corrected latent heat,kj/kg + +delta=(4*k*(T1-T2)*(2.99*10^(-4))*0.3/(a1*(a1-a2)*9.806*Hfg1*1000))^(0.25)*1000; + +Nul=4/3*H/delta; //average nusselt no. +q=Nul*k*(T1-T2)/H; // heat flow on an area about half the size of a desktop,W/m^2 +Q=q*H; //overall heat transfer per meter,kW/m + +m=Q/(Hfg1); //mass rate of condensation per meter,kg/(m*s) + +printf("\t overall heat transfer per meter is :%.1f kW/m^2\n",Q); +printf("\t film thickness at the bottom is :%.3f mm\n",delta); +printf("\t mass rate of condensation per meter. is : %.4f kg/(m*s)\n",m); + +//end \ No newline at end of file -- cgit