Thermodynamics HW Solutions 355

Thermodynamics HW Solutions 355 - Chapter 4 Transient Heat...

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Chapter 4 Transient Heat Conduction 4-78 A rectangular ice block is placed on a table. The time the ice block starts melting is to be determined. Assumptions 1 Heat conduction in the ice block is two-dimensional, and thus the temperature varies in both x - and y - directions. 2 The thermal properties of the ice block 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 the ice are given to be k = 2.22 W/m. ° C and α = 0.124 × 10 -7 m 2 /s. Analysis This rectangular ice block can be treated as a short rectangular block that can physically be formed by the intersection of two infinite plane wall of thickness 2 L = 4 cm and an infinite plane wall of thickness 2 L = 10 cm. We measure x from the bottom surface of the block since this surface represents the adiabatic center surface
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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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