Chapter 4
Transient Heat Conduction
478
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 twodimensional, 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.
 Fall '10
 Dr.DanielArenas
 Thermodynamics, Mass, Heat

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