blob: c198ebab973c15b7873d92a1791ea0c933467272 (
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
|
clear;
clc;
printf('FUNDAMENTALS OF HEAT AND MASS TRANSFER \n Incropera / Dewitt / Bergman / Lavine \n EXAMPLE 13.5 Page 834 \n')// Example 13.5
// Heat gain by the fluid passing through the inner tube
// Percentage change in heat gain with radiation shield inserted midway between inner and outer tubes
T2 = 300 ;//[K] Temperature of inner surface
D2 = .05 ;//[m] Diameter of Inner Surface
e2 = .05 ;// emissivity of Inner Surface
T1 = 77 ;//[K] Temperature of Outer Surface
D1 = .02 ;//[m] Diameter of Inner Surface
e1 = .02 ;// emissivity of Outer Surface
D3 = .035 ;//[m] Diameter of Shield
e3 = .02 ;// emissivity of Shield
stfncnstt = 5.670*10^-8 ;//[W/m^2.K^4] Stefan Boltzman Constant
//From Equation 13.20 Heat balance
q = stfncnstt*(%pi*D1)*(T1^4-T2^4)/(1/e1 + (1-e2)/e2*D1/D2) ;//[W/m]
RtotL = (1-e1)/(e1*%pi*D1) + 1/(%pi*D1*1) + 2*[(1-e3)/(e3*%pi*D3)] + 1/(%pi*D3*1) + (1-e2)/(e2*%pi*D2) ;//[m^-2]
q2 = stfncnstt*(T1^4 - T2^4)/RtotL; //[W/m]
printf('\n Heat gain by the fluid passing through the inner tube = %.2f W/m \n Percentage change in heat gain with radiation shield inserted midway between inner and outer tubes is = %.2f percent',q,(q2-q)*100/q);
|
