2–124E Repeat Problem 2–123E for the case of no solar
radiation incident on the surface.
2–125 Consider a steam pipe of length L, inner radius r1,
outer radius r2, and constant thermal conductivity k. Steam
flows inside the pipe at an average temperature of Ti with a
convection heat transfer coefficient of hi. The outer surface of
the pipe is exposed to convection to the surrounding air at a
temperature of T0 with a heat transfer coefficient of ho. Assuming
steady one-dimensional heat conduction through the pipe,
(a) express the differential equation and the boundary conditions
for heat conduction through the pipe material, (b) obtain
a relation for the variation of temperature in the pipe material
by solving the differential equation, and (c) obtain a relation
for the temperature of the outer surface of the pipe.