What thickness of insulation having a thermal conductivity as given in Problem 20.22 must be added to the steam pipe of Problem 20.40 in order that the outside temperature of the insulation does not...

What thickness of insulation having a thermal conductivity as given in Problem 20.22 must be added to the steam pipe of Problem 20.40 in order that the outside temperature of the insulation does not exceed 250F?

Problem 20.22

Solve Problem 20.20 if 3 in. of insulation having a thermal conductivity of 0.060 Btu/h ft
F is applied to the outside of the pipe. Neglect radiation from the insulation. What will be the outside surface temperature of the insulation?

Problem 20.20

If the steam line described in Problem 20.40 is bare and surrounded by still air at 70F, what total heat transfer would be predicted from a 20-ft length of bare pipe? Consider the bare pipe to be a black surface and the surroundings black at 70F.

Problem 20.40

Steam at 400 psi, 800F flows through a 1-in. schedule140 steel pipe at a rate of 10; 000 lb_m/h: Estimate the value of h that applies at the inside pipe surface.