Thermodynamics HW Solutions 610

Thermodynamics HW Solutions 610 - Chapter 7 External Forced...

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Chapter 7 External Forced Convection 7-83 A steam pipe is to be covered with enough insulation to reduce the exposed surface temperature to 30 ° C . The thickness of insulation that needs to be installed is to be determined. Assumptions 1 Heat transfer is steady since there is no indication of any change with time. 2 Heat transfer is one-dimensional since there is thermal symmetry about the centerline and no variation in the axial direction. 3 Thermal properties are constant. 4 The thermal contact resistance at the interface is negligible. Properties The thermal conductivities are given to be k = 52 W/m °C for cast iron pipe and k = 0.038 W/m °C for fiberglass insulation. Analysis The thermal resistance network for this problem involves 4 resistances in series. The inner radius of the pipe is r 1 = 2.0 cm and the outer radius of the pipe and thus the inner radius of insulation is r 2 = 2.3 cm. Letting r 3 represent the outer radius of insulation, the areas of the surfaces exposed to convection for a L
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This note was uploaded on 01/22/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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