blob: ac607cfe1e47da373b0c36cc13ac1d75918dd41a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
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)
|
