Chapter 3, Problem 84P

Superheated steam at an average temperature 20°C is transported through a steel pipe $(k=50\text{ W/m}{\text{.K, D}}_{\text{0}}\text{=8}{\text{.0 cm, D}}_{\text{i}}\text{=6}\text{.0 cm, and L=20}\text{.0 m)}$. The pipe is insulated with a 4-cm-thick layer of gypsum plaster (k = 0.5 WnrK). The insulated pipe is placed horizontally inside a warehouse where the average air temperature is 10°C. The steam and the air heat transfer coefficients are estimated to be 800 and 200 W/m² K, respectively. Calculate (a) the daily rate of heat transfer from the superheated steam, and (b) the teniperature on the outside surface of the gypsum plaster insulation.