FDiff_9

Differential element or ring on disk 1 to coaxial parallel disk 2

FDiff_9(r_1, r_2, x_1, x_2) provides the view factor from a differential element (1) or ring at the base of a right circular cylinder to a finite cirumferential ring on the interior of the the cylinder (2).

Inputs:
r_1 is the radius of the differential ring [m or ft]
r_2 is the radius of the cylinder [m or ft]
x_1 is the distance between the differential ring and the lower bound of the circumferential ring [m or ft]
x_2 is the distance between the differential ring and the upper bound of the circumferential ring [m or ft]

Example:
$UnitSystem SI K Pa J deg
"Note: This routine uses FDiff_9 to determine the view factor between the differential ring and a disk. Subtraction of the view factors between the upper and lower disks provides the view factor to the circumferential ring. The following program uses integration to calculate the view factor between the bottom of a right circular cylinder and the internal cylinder walls."
$TabStops 4 in
$VarInfo r units=m
r_2=1 [m]
x_1=0 [m] "setting x_1 to 0 results in a view factor from the base to the interior of the cylinder"
x_2=2 [m]
F=fdiff_9(r,r_2,x_1,x_2) "differential view factor"
F_12=integral(F*2*pi*r,r,0,r_2,0.0005 [m])/(pi*r_2^2)    "integration of differential view factor"
F_12`=f3d_17(r_2, x_2) "base to internal cylinder view factor relation"

{Solution:
F_12 = F_12` = 0.828}

View Factor Index