Critical Radius for Insulation. A metal steam pipe having an outside diameter of 30 mm has a surface temperature of 400 K and is to be insulated with an insulation having a thickness of 20 mm and a k...

Extracted text: Critical Radius for Insulation. A metal steam pipe having an outside diameter of 30 mm has a surface temperature of 400 K and is to be insulated with an insulation having a thickness of 20 mm and a k of 0.08 W/m· K. The pipe is exposed to air at 300 K and a convection coefficient of 30 W/m² · K. (a) Calculate the critical radius and the heat loss per m of length for the bare pipe. (b) Calculate the heat loss for the insulated pipe assuming that the surface temperature of the pipe remains constant. Ans. , (b) q = 54.4 W