Question

Heat Transfer

Problem 1: A 50-m long section of an AISI 316 stainless steel pipe,with an inner diameter of 20 cm and a wall thickness of 2 cm,transports steam through an open space of air at T=20°C and a heat transfer coefficient of 20 W/m?K. The steady-state inside wall temperature of the steam pipe is measured to be 180°C.Note that you can look up thermal conductivity and other thermo physical properties in Appendix A of the course textbook,or through other reputable sources. You MUST reference your source for material properties.

Determine the rate of heat loss from the steam pipe.

(b) If we want to reduce the heat loss to 10% of its value from part (a), what thickness of calcium silicate pipe insulation should be added to the outside of the pipe? You can assume that the inside surface temperature of the steam pipe remains at 180°C, as well as the outside air conditions. You may need to use an iterative solver (such as Excel's Goal Seek, in Data->What If Analysis->Goal Seek; or perhaps Matlab,or even a guess-and-check method). Ans: 3.3 cm