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Diffstat (limited to '2510/CH16/EX16.21/Ex16_21.sce')
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diff --git a/2510/CH16/EX16.21/Ex16_21.sce b/2510/CH16/EX16.21/Ex16_21.sce new file mode 100755 index 000000000..5b5e22465 --- /dev/null +++ b/2510/CH16/EX16.21/Ex16_21.sce @@ -0,0 +1,51 @@ +//Variable declaration: +//From table 16.5: +t2 = 75.0 //Temperature of water leaving the shell ( C) +t1 = 35.0 //Temperature of water entering the shell ( C +T2 = 75.0 //Temperature of oil leaving the tube ( C) +T1 = 110.0 //Temperature of oil entering the tube ( C) +mw = 1.133 //Mass flowrtae of water (kg/s) +cpw = 4180.0 //Heat capacity of water (J/kg.K) +cpo = 1900.0 //Heat capacity of oil (J/kg.K) +p = 850.0 //Density of oil (kg/m^3) +Di = 0.01905 //Inside diameter of tube (m) +V = 0.3 //Average velocity of oil flow inside the tube (m/s) +Np = 2.0 //Number of passes +Uc = 350.0 //Overall heat transfer coefficient for clean heat exchanger (W/m^2) +Rf = 0.00027 //Fouling factor (m^2.K/w) +pi = %pi + +//Calculation: +Cw = mw*cpw //Water capacitance rate (W/K) +Q = Cw*(t2-t1) //Heat load (W) +Co = Q/(T1-T2) //Oil capacitance rate (W/K) +mo = Co/cpo //Total flowrate of oil (kg/s) +if (Cw<Co) then + Cmin = Cw //Minimum capacitance rate (W/K) + Cmax = Co //Maximum capacitance rate (W/K) +else + Cmin = Co //Minimum capacitance rate (W/K) + Cmax = Cw //Maximum capacitance rate (W/K) +end +m_ot = p*V*(pi/4.0)*Di**2 //Oil flowrate per tube (kg/s) +Nt = mo/m_ot //Number of tubes per pass +N = Nt*Np //Number of tubes +DT1 = T2-t1 //Temperature driving force 1 ( C) +DT2 = T1-t2 //Temperature driving force 2 ( C) +DTlm1 = ((DT1-DT2)/log(DT1/DT2)) //Log mean temperature driving force for ideal countercurrent heat exchanger ( C) +P = (t2-t1)/(T1 - t1) //Dimensionless parameter P +R = (T1-T2)/(t2-t1) //Dimensionless parameter R +//From figure 16.7: +F = 0.81 //Correction factor +DTlm2 = F*DTlm1 //Log mean temperature driving force for shell and tube exchanger ( C) +Ud = 1.0/(1.0/Uc+Rf) //Dirty overall heat transfer coefficient (W/m^2.K) +A = Q/(Ud*DTlm2) //Required heat transfer area (m^2) +L = A/(N*pi*Di) //Tube length (m) +N = round(N*10**-1)/10**-1 + +//Result: +printf("1. The mass flow rate of the oil is : %.2f kg/s .",mo) +printf("2. The minimum and maximum heat capacity rate is : %.0f and %.1f W/K",Cmin,Cmax) +printf("3. The heat load, Q is : %.0f W .",Q) +printf("4. The total number of tubes is : %f ",N) +printf("5. The tube length is : %.1f m .",L) |