blob: b660a3be6083ff0bec4334385bff06541d7eeead (
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
|
clc;
clear;
//Example 3.38
v=23.13*10^-6 ; //[m^2/s]
k=0.0321 ; //[W/m.K]
Beta=2.68*10^-3; //[K^-1]
Tw=443 ;//[K]
T_inf=303 ; //[K]
dT=Tw-T_inf; //[K]
g=9.81 ; //[m/s^2]
Npr=0.688; //Prandtl number
D=100 ; //Diameter [mm]
D=D/1000 //Diameter [m]
Nra=(g*Beta*dT*(D^3)*Npr)/(v^2)
Nnu=0.53*(Nra^(1.0/4.0)) //Nusselt number
h=Nnu*k/D //[W/(m^2.K)]
h=7.93 //Approximation
e=0.90; //Emissivity
sigma=5.67*10^-8 ;
//Q=Q_conv+Q_rad //Total heat loss
//for total heat loss per meter length
Q_by_l=h*%pi*D*dT+sigma*e*%pi*D*(Tw^4-T_inf^4) //[W/m]
printf("Total heat loss per metre length of pipe is %f W/m",Q_by_l)
|
