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 --- 2510/CH22/EX22.24/Ex22_24.sce | 46 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100755 2510/CH22/EX22.24/Ex22_24.sce (limited to '2510/CH22/EX22.24') diff --git a/2510/CH22/EX22.24/Ex22_24.sce b/2510/CH22/EX22.24/Ex22_24.sce new file mode 100755 index 000000000..365c0072e --- /dev/null +++ b/2510/CH22/EX22.24/Ex22_24.sce @@ -0,0 +1,46 @@ +//Variable declaration: +m1 = 62000 //Mass flowrate of alcohol (lb/h) +h1 = 365 //Enthalpy of vapour (Btu/lb) +cp = 1 //Heat capacity of water (Btu/lb. F) +T1 = 85 //Entering temperature of water ( F) +T2 = 120 //Exit temperature of water ( F) +a1 = 2.11 //Flow area for the shell side (ft^2) +N = 700 //Total number of tubes +a2 = 0.546 //Flow area per tube (in^2/tube) +n = 4 //Number of tube passes +p = 62.5 //Density of water (lb/ft^3) +L = 16 //Length of condenser (ft) +hio = 862.4 //Cooling water inside film coefficient (Btu/h.ft^2. F) +g = 9.8 //Gravitational accleration (m^2/s) +Rf = 0.003 //Fouling factor (Btu/h.ft^2. F) + +//Calculation: +Q1 = m1*h1 //Heat loss from alcohol (Btu/h) +Q2 = Q1 //Heat gained by water (Btu/h) +DT = T2-T1 //Temperature difference ( F) +m2 = Q2/(cp*DT) //Water mass flow rate (lb/h) +LMTD = ((T2-32)-(T1-32))/log((T2-32)/(T1-32)) //Log mean temperature difference ( F) +at = (N*a2)/(144*n) //Total flow area for tube side (ft^2) +G1 = m1/a1 //Mass velocity of flow in shell side (lb/h.ft^2) +G2 = m2/at //Mass velocity of flow in tube side (lb/h.ft^2) +V = G2/(3600*p) //Velocity of water (ft/s) +G3 = m1/(L*N)**(2/3) //Loading G (lb/h.ft) +//For alcohol: +kf = 0.105 //Thermal conductivity (Btu/h.ft. F) +muf = 0.55*2.42 //Dynamic viscosity (lb/ft.h) +sf = 0.79 // +pf = sf*p //Density (lb/ft^3) +h = 151*(((kf**3)*(pf**2)*g*muf)/((muf**2)*n*G3))**(1/3) //Heat transfer coefficient for the shell side (Btu/h.ft^2. F) +ho = h //Outside heat transfer coefficient of the tube bundle (Btu/h.ft^2. F) +Uc = (hio*ho)/(hio+ho) //Overall heat transfer coefficient for a new (clean) heat exchanger (Btu/h.ft^2. F) +A = N*L*0.2618 //Area for heat transfer (ft^2) +Ud = Q1/(A*DT) //Design (D) overall heat transfer coefficient (Btu/h.ft^2. F) +Rd = (Uc-Ud)/(Uc*Ud) //Dirt (d) factor (Btu/h.ft^2. F) + +//Result: +printf("The dirt (d) factor is : %.4f Btu/h.ft^2. F .",Rd) +if (Rd>Rd) then + printf("Therefore, the exchanger as specified is unsuitable for these process conditions since the fouling factor is above the recommended value. Cleaning is recommended.") +else + printf("Therefore, the exchanger as specified is suitable for these process conditions since the fouling factor is below the recommended value. Cleaning is not recommended.") +end -- cgit