SF_5
Function SF_5 provides the shape factor ([m] or [ft])for conduction between the internal and external surfaces of a tube associated with an N-sided regular polygon within an N-sided regular polygon.
Inputs:
d_in = diameter of circle inscribed in inner polygon ([m] or [ft])
d_out = diameter of circle inscribed in outer polygon ([m] or [ft])
L = length of tube ([m] or [ft])
N = number of sides ([m] or [ft])
Example: SF = SF_5(d_in, d_out, L, N)
Reference: Rohsenow W., Harnet J. & Cho, Y. (1998). Handbook of heat transfer, 3rd ed. Madison, Wisconsin: McGraw Hill. p. 3.21.