Differential ring element on surface of a disk to a coaxial sphere
FDiff_6(r1, r2, h) provides the view factor from a differential ring (1) on a disk to a coaxial sphere (2).
Inputs:
r1 is the radius of the differential ring [m or ft]
r2 is the radius of the sphere [m or ft]
h is the distance between the disk and center of the sphere [m or ft]
Example:
"The following program uses integration to calculate the view factor of the entire disk to a sphere. This view factor could be found more directly using F3D_16, but use of the differential view factor allows the radiation heat transfer to be calculated even if the disk temperature varies with radius. "
r_o=1[m] "radius of disk and sphere"
h=1[m] "height of center of sphere above disk"
A_disk=pi*r_o^2 "area of disk"
F=FDiff_6(r,r_o,h) "view factor from the differential ring to the sphere"
F_12=integral(F*2*pi*r,r,0,r_o)/A_disk "view factor between the entire disk (1) and the sphere"
A_sphere=4*pi*r_o^2 "area of the sphere"
F_12`=F3D_16(r_o,h)*A_sphere/A_disk "view factor between the disk and the sphere using F3D_16 - compare to F_12"
{Solution: F_12 = F_12` =0.5858 }
Reference: Howell, www.me.utexas.edu/~howell/sectionb/B-91.html from Feingold and Gupta, 1970