SF_15
Function SF_15 provides the shape factor ([m] or [ft]) for conduction between the inner and outer surfaces of a tube defined by two confocal ellipses.
Inputs:
a = major radius of inner ellipse ([m] or [ft])
b = minor radius of inner ellipse ([m] or [ft])
c = major radius of outer ellipse ([m] or [ft])
d = minor radius of outer ellipse ([m] or [ft])
L = length of tube ([m] or [ft])
Example: SF = SF_15(a, b, c, d, L)
Reference: Wong, H. (1977). Heat transfer for engineers. London: Longman Group Ltd. p. 21.