FDiff_14

Element on longitudinal strip on inside of right circular cylinder to the outer concentric right circular cylinder

FDiff_14(r1, r2, z, h) provides the view factor from a differential element (1) on a longitudinal strip on the inside of right circular cylinder with radius r2 to the interior surface of the outeter concentric right circular cylinder (2).

Inputs:
r1   is the radius of the smaller concentric cylinder [m or ft]
r2   is the radius of the larger concentric cylinder [m or ft]
z     is the height of the element above the base [m or ft]
h     is the height of the cylinders [m or ft]

Example:
$UnitSystem SI K Pa J deg
"The following program compares the integrated view factor between the inside of a cylinder with its base to the more direct result from f3d_5.    FDiff_14 can be used when the surface temperature or properties vary with position."
$VarInfo z units=m
r1=0.5 [m]
r2=1 [m]
h=2 [m]
F_12=integral(fdiff_14(r1,r2,z, h)*2*pi*r2,z,0,h)/(2*pi*r2*h)
F_12`=f3d_5(r1, r2, h)

{Solution:
F_12 = F_12` = 0.3286}

Reference: http://www.me.utexas.edu/~howell/sectionb/B-56.html

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