Thermodynamics HW Solutions 345

Thermodynamics HW Solutions 345 - Chapter 4 Transient Heat...

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Chapter 4 Transient Heat Conduction 4-73 A short cylinder is allowed to cool in atmospheric air. The temperatures at the centers of the cylinder and the top surface as well as the total heat transfer from the cylinder for 15 min of cooling are to be determined. Assumptions 1 Heat conduction in the short cylinder is two-dimensional, and thus the temperature varies in both the axial x - and the radial r - directions. 2 The thermal properties of the cylinder are constant. 3 The heat transfer coefficient is constant and uniform over the entire surface. 4 The Fourier number is τ > 0.2 so that the one-term approximate solutions (or the transient temperature charts) are applicable (this assumption will be verified). Properties The thermal properties of brass are given to be , ρ = 8530 kg / m 3 C kJ/kg 389 . 0 ° = p C , , and C W/m 110 ° = k α 339 10 5 . m /s 2 . Analysis This short cylinder can physically be formed by the intersection of a long cylinder of radius D /2 = 4 cm and a plane wall of thickness 2 L = 15 cm. We measure x from the midplane.
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This note was uploaded on 01/19/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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