SF_26
Function SF_26 provides the shape factor ([m] or [ft]) for radial conduction through a hollow sphere.
Inputs:
r_in = inner radius of sphere ([m] or [ft])
r_out = outer radius of sphere ([m] or [ft])
Example: SF = SF_26(rin, rout)
Reference: Barron, R.F., G.F. Nellis, J. A. Pfotenhauer, Cryogenic Heat Transfer, 2nd Edition, Taylor and Francis, New York, (2015).