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clc();
clear;
// To calculate heat loss by natural convection in a horizontal nominal steam pipe
D=0.375; // Outer diameter in ft
T1=200; // Pipe surface temperature in degF
T2=70; // Air temperature in degF
Tf=(T1+T2)/2; // Film temperature at whih physical properties is to be measured
delT=T1-T2;
rho=0.0667/32.2; // Density in slug/ft^3
u=0.0482/32.2; // Viscosity in slug/ft-hr
b=1/(460+T2 );
Cp=0.241*32.2; // Heat capacity in Btu/slug-ft
// The value of specific heat is related to 1 lb mass so it must be multiplied to 32.2 to convert it into slugs
k=0.0164; // Thermal conductivity in Btu/hr-ft-degF
g=32.2*3600;
// Unit of time used is hour so it must be converted to sec. Hence 3600 is multiplied
Ngr=D^3*rho^2*b*g*delT/(u^3); // Grasshops number
Npr=u*Cp/k; // Prandtls number
A=log(Ngr*Npr);
// Tha value of A is 6.866
// Now seeing the value of nusselt number from the table
Nnu=25.2; // Nusselt number
h=Nnu*k/D; // Heat transfer coefficient
q=h*delT; // Heat loss per unit area in Btu/hr
printf("Heat loss per unit square foot is %d Btu/hr-ft^2",q);
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