diff options
Diffstat (limited to '2510/CH15')
| -rwxr-xr-x | 2510/CH15/EX15.10/Ex15_10.sce | 20 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.11/Ex15_11.sce | 39 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.12/Ex15_12.sce | 24 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.14/Ex15_14.sce | 33 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.15/Ex15_15.sce | 12 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.16/Ex15_16.sce | 10 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.18/Ex15_18.sce | 10 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.19/Ex15_19.sce | 10 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.2/Ex15_2.sce | 10 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.20/Ex15_20.sce | 14 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.21/Ex15_21.sce | 10 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.3/Ex15_3.sce | 21 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.4/Ex15_4.sce | 19 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.5/Ex15_5.sce | 17 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.6/Ex15_6.sce | 21 | ||||
| -rwxr-xr-x | 2510/CH15/EX15.8/Ex15_8.sce | 61 |
16 files changed, 331 insertions, 0 deletions
diff --git a/2510/CH15/EX15.10/Ex15_10.sce b/2510/CH15/EX15.10/Ex15_10.sce new file mode 100755 index 000000000..744313fa8 --- /dev/null +++ b/2510/CH15/EX15.10/Ex15_10.sce @@ -0,0 +1,20 @@ +//Variable declaration: +MC = 2000.0 +mc = 1000.0 +U = 2000.0 +A = 10.0 +T1 = 300.0 +t1 = 60.0 +e = %e + +//Calculation: +B = 1.0/mc +b = 1.0/MC +x = B/b +y = U*(B-b) +T2 = ((x-y)*T1 + x*(e-y)*t1)/(2*e-1) +t2 = t1+(T1-T2)/x + +//Result: +printf("T2 = : %.0f ",T2) +printf("t2 = : %.0f ",t2) diff --git a/2510/CH15/EX15.11/Ex15_11.sce b/2510/CH15/EX15.11/Ex15_11.sce new file mode 100755 index 000000000..2b49cce78 --- /dev/null +++ b/2510/CH15/EX15.11/Ex15_11.sce @@ -0,0 +1,39 @@ + +//Variable declaration: +h1 = 1200.0 //Hot film coefficient (Btu/h.ft^2..) +h2 = 1175.0 //Cold film coefficient (Btu/h.ft^2..) +L = 200.0 //Length of pipe (ft) +MC = 30000.0 +mc = 22300.0 +T1 = 300.0 //Inlet temperature of hot fluid in pipe (.) +t1 = 60.0 //Inlet temperature of cold fluid in pipe (.) +syms T2 //Outlet temperature of hot fluid . +syms t2 //Outlet temperature of cold fluid . +//From table 6.2: +ID = 2.067 //Inside diameter of pipe (in) +OD = 2.375 //Outside diameter of pipe (in) +Dx = 0.154 //Thickness of pipe (in) +Ai = 0.541 //Inside sectional area of pipe (ft^2/ft) +k = 25.0 //Thermal conductivity of pipe (Btu/h) + +//Calculation: +Ui = 1.0/((1.0/h1) +(Dx/(k*12.0))+(1.0/(h2*(OD/ID)))) //Overall heat transfer coefficient (Btu/h.ft^2..) +Ai1 = Ai*L //Inside area of pipe (ft^3/ft) +QH = MC*(T1-T2) //Heat transfer rate of hot fluid (Btu/h) +QC = mc*(t2-t1) //Heat transfer rate of cold fluid (Btu/h) +t2ht = 195 //t2 by hit and trial +[x] = fsolve(T2,QC-QH) +T2 = x(1) +DTlm = (T1-t1-T2+t2)/log((T1-t1)/(T2-t2)) //Log mean temperature difference (.) +Q = Ui*Ai1*subst(t2ht,t2,DTlm) //Total heat transfer rate (Btu/h) + +//Result: +disp("T2 :") +disp(subst(t2ht,t2,T2)) + +disp("t2 :") +disp(subst(t2ht,t2,t2)) + +disp("Qdot :") +disp(Q/10**6) +disp("x 10**6 Btu/h") diff --git a/2510/CH15/EX15.12/Ex15_12.sce b/2510/CH15/EX15.12/Ex15_12.sce new file mode 100755 index 000000000..fc71588f8 --- /dev/null +++ b/2510/CH15/EX15.12/Ex15_12.sce @@ -0,0 +1,24 @@ + +//Variable declaration: +B = 3.33*10**-5 +b = 4.48*10**-5 +//From example 15.11: +A = 108.2 //Inside area of pipe (ft^3/ft) +U = 482 //Overall heat transfer coefficient (Btu/h.ft^2..) +MC = 30000.0 +mc = 23000.0 +T1 = 300.0 //Inlet temperature of hot fluid in pipe (.) +t1 = 60.0 //Inlet temperature of cold fluid in pipe (.) +e = %e + +//Calculation: +//From equation 15.28: +T2 = ((B/b)*(e**(U*A*(B-b))-1)*t1+T1*(B/b-1))/((B/b)*e**(U*A*(B-b))-1) //Outlet temperature of hot fluid (.) +//From equation 15.32: +t2 = ((b/B)*(e**(U*A*(b-B))-1)*T1+t1*(b/B-1))/((b/B)*e**(U*A*(b-B))-1) //Outlet temperature of cold fluid (.) +DT = ((T2-t1)-(T1-t2))/(log((T2-t1)/(T1-t2))) //Log mean difference temperature (.) +Q1 = U*A*DT //Heat transfer rate of hot fluid (Btu/h) +Q2 = MC*(T1-T2) //Heat transfer rate of cold fluid (Btu/h) +Q2 = round(Q2 * 10**-3)/10**-3 +//Result: +printf("The heat load is : %f Btu/h.",Q2) diff --git a/2510/CH15/EX15.14/Ex15_14.sce b/2510/CH15/EX15.14/Ex15_14.sce new file mode 100755 index 000000000..ac607cfe1 --- /dev/null +++ b/2510/CH15/EX15.14/Ex15_14.sce @@ -0,0 +1,33 @@ +//Variable declaration: +Ts = 100.0 //Saturation temperature (u00b0C) +t1 = 25.0 //Initial temperature of water (u00b0C) +t2 = 73.0 //Final temperature of water (u00b0C) +m = 228.0/3600.0 //Mass flow rate of water (kg/s) +cp = 4174.0 //Heat capacity of water (J/kg.K) +m_s = 55.0/3600.0 //Mass flow rate of steam (kg/s) +h_vap = 2.26*10**26 //Latent heat of condensation (J/kg) +k = 54.0 //Thermal conductivity for 0.5% carbon steel (W/m.K) +rii = 0.013 //Inner radius of inner %pipe of the double %pipe heat exchanger (m) +roi = 0.019 //Outer radius of inner %pipe of the double %pipe heat exchanger (m) +Rf = 0.0002 //Fouling factor (m^2.K/W) +Uc = 0.00045 //Clean overall heat transfer coefficient (W/m^2.K) + +//Calculation: +DT1 = Ts-t1 //Temperature driving force at end 1 (K) +DT2 = Ts-t2 //Temperature driving force at end 2 (K) +DTlm = (DT1-DT2)/(log(DT1/DT2)) //Log mean difference temperature (u00b0C) +Cw =m*cp //Capacitance rate of water (W/K) +Q = Cw*(t2-t1) //Heat transfer rate (W) +Qmax1 = Cw*(Ts-t1) //Maximum heat term from the water stream (W) +Qmax2 = m_s*h_vap //Maximum heat term from the steam (W) +E = Q/Qmax1 //Effectiveness +Lmin = (Q*(log(roi/rii)))/(2*%pi*k*(Ts-t1)) //Minimum required length of heat exchanger (m) +Ud = 1.0/(1.0/Uc+Rf) //Dirty overall heat transfer coefficient (W/m^2.K) +ud = round(1/Ud * 10**-1)/10**-1 + +//Result: +printf("1. The temperature profile of the water and steam along the length of the exchanger is : %.0f C .",DTlm) +printf("2. Effectiveness of energy from steam to heat the water is : %.3f .",E) +printf("3. The minimum length of the heat exchanger is : %.3f m .",Lmin) +printf("4. The dirty overall heat transfer coefficient : %.5f W/m^2.K",Ud) +printf("5. U_dirty: %f W/m^2.K",ud) diff --git a/2510/CH15/EX15.15/Ex15_15.sce b/2510/CH15/EX15.15/Ex15_15.sce new file mode 100755 index 000000000..d635dbd84 --- /dev/null +++ b/2510/CH15/EX15.15/Ex15_15.sce @@ -0,0 +1,12 @@ +//Variable declaration: +Q = 12700.0 //Heat transfer rate (W) +Ud = 2220.0 //Dirty overall heat transfer coefficient (W/m^2.K) +DTlm = 47.0 //Log mean difference temperature (u00b0C) +rii = 0.013 //Inner radius of inner %pipe of the double %pipe heat exchanger (m) +//Calculation: +A = Q/(Ud*DTlm) //Heat transfer area (m^2) +L = A/(2*%pi*rii) //Tube length (m) + +//Result: +printf("The heat transfer area is : %.4f m^2.",A) +printf("The length of the heat exchanger is : %.2f m.",L) diff --git a/2510/CH15/EX15.16/Ex15_16.sce b/2510/CH15/EX15.16/Ex15_16.sce new file mode 100755 index 000000000..b350a9c86 --- /dev/null +++ b/2510/CH15/EX15.16/Ex15_16.sce @@ -0,0 +1,10 @@ +//Variable declaration: +Ud = 2220.0 //Dirty overall heat transfer coefficient (W/m^2.K) +A = 0.1217 //Heat transfer area (m^2) +Cw = 264.0 //Capacitance rate of water (W/K) + +//Calculation: +NTU = (Ud*A)/Cw //Number of transfer units of the exchanger + +//Result: +printf("The number of transfer units (NTU) of the exchanger is : %.2f .",NTU) diff --git a/2510/CH15/EX15.18/Ex15_18.sce b/2510/CH15/EX15.18/Ex15_18.sce new file mode 100755 index 000000000..d0fb90e83 --- /dev/null +++ b/2510/CH15/EX15.18/Ex15_18.sce @@ -0,0 +1,10 @@ +//Variable declaration: +Ao = 1.85 //Area of heat exchanger (ft^2) + +//Calculation: +//From figure 15.6: +y = 0.560*10**-3 //Intercept 1/UoAo (..h/Btu) +ho = 1.0/(Ao*y) //Thermal conductivity for heat exchanger (Btu/h.ft^2..) + +//Result: +printf("Thermal conductivity for the heat exchanger is : %.0f Btu/h.ft^2.. .",ho) diff --git a/2510/CH15/EX15.19/Ex15_19.sce b/2510/CH15/EX15.19/Ex15_19.sce new file mode 100755 index 000000000..c66dbae43 --- /dev/null +++ b/2510/CH15/EX15.19/Ex15_19.sce @@ -0,0 +1,10 @@ +//Variable declaration: +//From figure 15.7: +a = 0.00126 +b = 0.0276 + +//Calculation: +ho = 1.0/a //The value of ho (Btu/h.ft^2..) + +//Result: +printf("Thermal conductivity is : %.0f Btu/h.ft^2.. .",ho) diff --git a/2510/CH15/EX15.2/Ex15_2.sce b/2510/CH15/EX15.2/Ex15_2.sce new file mode 100755 index 000000000..e44dc7bc7 --- /dev/null +++ b/2510/CH15/EX15.2/Ex15_2.sce @@ -0,0 +1,10 @@ +//Variable declaration: +Q = 12000.0 //Heat transfer rate (Btu/h) +U = 48.0 //Overall heat coefficient (Btu/ft^2.h..) +DTlm = 50.0 //Log mean temperature difference (.) + +//Calculation: +A = Q/(U*DTlm) //Area of exchanger (ft^2) + +//Result: +printf("The area of the exchanger is : %.0f ft^2 .",A) diff --git a/2510/CH15/EX15.20/Ex15_20.sce b/2510/CH15/EX15.20/Ex15_20.sce new file mode 100755 index 000000000..8f0f73974 --- /dev/null +++ b/2510/CH15/EX15.20/Ex15_20.sce @@ -0,0 +1,14 @@ +//Variable declaration: +Di = 0.902/12.0 //Inside diameter of tube (ft) +Do = 1.0/12.0 //Outside diameter of tube (ft) +k = 60.0 //Thermal conductivity of tube (Btu/h.ft^2..) + +//Calculation: +//From example 15.19: +a = 0.00126 +Dr = (Do - Di)/2.0 //Radial thickness of tube wall (ft) +Rw = Dr/k //Resistance of wall (Btu/h..) +ho = 1.0/(a-Rw) //The revised ho (Btu/h.ft^2..) + +//Result: +printf("The revised ho is : %.0f Btu/h.ft^2.. .",ho) diff --git a/2510/CH15/EX15.21/Ex15_21.sce b/2510/CH15/EX15.21/Ex15_21.sce new file mode 100755 index 000000000..817c8e347 --- /dev/null +++ b/2510/CH15/EX15.21/Ex15_21.sce @@ -0,0 +1,10 @@ +//Variable declaration: +a1 = 0.00044 //Term 'a' for U_clean +a2 = 0.00089 //Term 'a' for U_dirty + +//Calculation: +Rs = a2 - a1 //Resistance associated with the scale +hs = 1.0/Rs //Scale film coefficient (Btu/h.ft^2..) + +//Result: +printf("The scale film coefficient neglecting the wall resistance is: %.0f Btu/h.ft^2.. .",hs) diff --git a/2510/CH15/EX15.3/Ex15_3.sce b/2510/CH15/EX15.3/Ex15_3.sce new file mode 100755 index 000000000..e529b2f38 --- /dev/null +++ b/2510/CH15/EX15.3/Ex15_3.sce @@ -0,0 +1,21 @@ +//Variable declaration: +Q = 56760 //Heat transfer rate (Btu/h) +U = 35.35 //Overall heat coefficient (Btu/ft.h..) +A = 32.1 //Area of exachanger (ft^2) +t1 = 63.0 //Outlet cold water temperature (.) +T1 = 164 //Outlet hot water temperature (.) +T2 = 99 //Inlet hot water temperature (.) +syms t2 //Inlet cold water temperature (.) + +//Calculation: +DTlm = Q/(U*A) //Log mean temperature difference (.) +dT1 = T1-t1 //Temperature approach at pipe outlet (.) +dT2 = T2-t2 //Temperature approach at pipe inlet (.) +Eq = (dT2-dT1)/log(dT2/dT1)-DTlm +R = eval(subst(0,t2,Eq)) //Inlet cold water temperature (.) + +//Result: +disp("The inlet cold water temperature is : ") +disp(round(R)) + +// There is some mistake in calculation in book. Please calculate manually. diff --git a/2510/CH15/EX15.4/Ex15_4.sce b/2510/CH15/EX15.4/Ex15_4.sce new file mode 100755 index 000000000..9b2c2d187 --- /dev/null +++ b/2510/CH15/EX15.4/Ex15_4.sce @@ -0,0 +1,19 @@ +//Variable declaration: +m = 14.6 //Flow rate of water inside the tube (lb/min) +Cp = 1 //Heat capacity of water (Btu/lb..) +t2 = 79 //Initial temperature of water (.) +t1 = 63 //Final temperature of water (.) +//From example 15.3: +Q1 = 56760 //Old heat transfer rate (Btu/h) + +//Calculation: +Q2 = m*Cp*(t2-t1) //New heat transfer rate (Btu/min) + +//Result: +printf("The new heat transfer rate is : %.0f Btu/min.",Q2) +printf("Or, the new heat transfer rate is : %.0f Btu/h.",Q2*60) +if (Q1==Q2) then + printf("This result agree with the Qu02d9 provided in the problem statement. Shakespeare is wrong, nothing is rotten there.") +else + printf("This result does not agree with the Qu02d9 provided in the problem statement. Shakespeare is right, something is indeed rotten.") +end diff --git a/2510/CH15/EX15.5/Ex15_5.sce b/2510/CH15/EX15.5/Ex15_5.sce new file mode 100755 index 000000000..c92af9937 --- /dev/null +++ b/2510/CH15/EX15.5/Ex15_5.sce @@ -0,0 +1,17 @@ +//Variable declaration: +T1 = 210.0 //Initial temperature of oil (.) +T2 = 170.0 //Final temperature of oil (.) +T3 = 60.0 //Surface temperature of oil (.) +m = 8000.0 //Flow rate of oil inside tube (lb/h) +cp = 0.55 //Heat capacity of oil (Btu/lb..) +U = 63.0 //Overall heat teansfer coefficient (Btu.h.ft^2..) + +//Calculation: +DT1 = T1-T3 //Temperature difference 1 (.) +DT2 = T2-T3 //Temperature difference 2 (.) +DTlm = (DT1-DT2)/log(DT1/DT2) //Log mean temerature difference (.) +Q = m*cp*(T1-T2) //Heat transferred (Btu/h) +A = Q/(U*DTlm) //Heat transfer area (ft^2) + +//Result: +printf("The required heat transfer area is : %.2f ft^2 .",A) diff --git a/2510/CH15/EX15.6/Ex15_6.sce b/2510/CH15/EX15.6/Ex15_6.sce new file mode 100755 index 000000000..07d4c5ca8 --- /dev/null +++ b/2510/CH15/EX15.6/Ex15_6.sce @@ -0,0 +1,21 @@ +//Variable declaration: +T1 = 140.0 //Initial temperature of hot water (.) +T2 = 110.0 //Final temperature of hot water (.) +T3 = 60.0 //Initial temperature of cold water (.) +T4 = 90.0 //Initial temperature of cold water (.) +DTlm2 = 50.0 //Log mean temerature difference for countercurrent flow, a constant (.) (part 2) +m = 100.0*60 //Water flow rate (lb/h) +cp = 1.0 ////Heat capacity of water (Btu/lb..) +U = 750.0 //Overall heat teansfer coefficient (Btu.h.ft^2..) + +//Calculation: +DT1 = T1-T3 //Temperature difference 1 (.) (part 1) +DT2 = T2-T4 //Temperature difference 2 (.) +DTlm1 = (DT1-DT2)/log(DT1/DT2) //Log mean temerature difference (.) +Q = m*cp*(T1-T2) //Heat transferred (Btu/h) +Ap = Q/(U*DTlm1) //Heat transfer area for parallel flow (ft^2) +Ac = Q/(U*DTlm2) //Heat transfer area for counter flow (ft^2) + +//Result: +printf("1. The double pipe co-current flow is : %.2f ft^2 .",Ap) +printf("1. The double pipe countercurrent flow is : %.2f ft^2 .",Ac) diff --git a/2510/CH15/EX15.8/Ex15_8.sce b/2510/CH15/EX15.8/Ex15_8.sce new file mode 100755 index 000000000..d9c07b2a4 --- /dev/null +++ b/2510/CH15/EX15.8/Ex15_8.sce @@ -0,0 +1,61 @@ +//Variable declaration: +uC = 3.7*10**-4 //Viscosity of benzene (lb/ft.s) +uH = 2.05*10**-4 //Viscosity of water @200 . (lb/ft.s) +u2 = 2.16*10**-4 //Viscosity of water @192 . (lb/ft.s) +pC = 54.8 //Density of benzene (lb/ft^3) +pH = 60.13 //Density of water (lb/ft^3) +cpC = 0.415 //Specific heat capacity of benzene (Btu/lb..) +cpH = 1 //Specific heat capacity of water (Btu/lb..) +sgC = 0.879 +kC = 0.092 //Thermal conductivity of benzene (Btu/h.ft..) +kH = 0.392 //Thermal conductivity of water @200 . (Btu/h.ft..) +k2 = 0.390 //Thermal conductivity of water @192 . (Btu/h.ft..) +mC = 2500 //Flow rate of benzene (lb/s) +mH = 4000 //Flow rate of water (lb/s) +Re = 13000 //Reynolds number +dTc = 120-60 //Difference in temperature heating for benzene +Tw = 200 //Temperatperature of hot water (.) +//For 2-inch schedule 40 pipe +Ai = 0.541 //Inside area of pipe (ft^2/ft) +Ao = 0.622 //Outside area of pipe (ft^2/ft) +Di = 2.067 //Inside diameter of pipe (inch) +Do = 2.375 //Outside diameter of pipe (inch) +Si = 0.0233 //Inside surface area of pipe (ft^2) +dXw = 0.128 //Width of pipe (ft) +pi = %pi + +//For 4-inch schedule 40 pipe +Dio = 4.026 //Inside diameter of pipe (inch) +Doi = Do //Outside diameter of pipe (inch) +kw = 26 + +//Calculations: +function [a] = St(Re,Pr) //Dittus Boelter equation + a = 0.023*Re**-0.2*Pr**-0.667 +endfunction + +//For inside tubes: +Dicalc = 4*mC/(Re*pi*uC)/3600 //Inside diameter (ft) +mHcalc = Re*pi*uH*(Doi+Dio)/4*3600/12 //Mass flow rate of water (lb/h) +Q = mC*cpC*dTc //Heat in water (Btu/h) +dTH = Q/mH //Temperature difference of water (.) +THo = Tw - dTH //Outlet temperature of water (.) +THav = (Tw+THo)/2 //Average temperature of water (.) +//For benzene: +PrC = cpC*uC/kC*3600 //Prandtl number +StC = round(St(13000, PrC) * 10**5)/10**5 //Stanton number +hi = StC*cpC*mC/Si //Heat transfer coefficient (Btu/h.ft^2..) +//For water: +ReH = 4*mH/3600/(pi*u2*(Doi+Dio)/12) //Reynolds number +PrH = cpH*(u2)/k2*3600 //Prandtl number +StH = round(St(ReH, PrH) * 10**5)/10**5 //Stanton number +Sann = pi/4*(Dio**2-Doi**2)/144 //Surface area of annulus (ft^2) +ho = round(StH*cpH*mH/Sann) //Heat transfer coefficient (Btu/h.ft^2..) +//For pipe: +Dlm = (Do-Di)/log(Do/Di)*12 //Log mean difference in diameter (ft) +Uo = 1/(Do/Di/hi + dXw*Do/kw/Dlm + 1/ho) //Overall heat transfer coefficient (Btu/h.ft^2..) +dTlm = (124.4-80)/log(124.4/80) //Log mean temperature difference (.) +L = Q/(Uo*0.622*dTlm) //Length of pipe (ft) + +//Result: +printf("The required length of pipe: %.1f ft",L) |