Question

A pipe is transporting saturated steam at 1 bar (100°C) . The pipe has an inside diameter of 100 mm with a 9 mm thick wall. The pipe is mild steel with a thermal conductivity of 80 W m-1 K-1. Covering the pipe is a 20 mm thick layer of polythene insulation with a thermal conductivity of 0.04 W m-1 K-1. The convective heat transfer coefficient of the steam is 513.4 W m-2 K-1. The convective heat transfer coefficient of the air around the insulated pipe is 22.9 W m-2 K-1 which is at 22°C. Calculate the heat lose per unit area (1 m) of the insulated pipe in watts (W) (1 DP). Neglect radiation heat transfer.

Answer 1

Summary: Heat loss per unit area = 142.93 W