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CIRCLE YOUR DIVISION:
Div. 1 (9:30 am)
Div. 2 (11:30 am)
Div. 3 (2:30 pm)
Prof
.
Ruan
.
Naik
Mr
.
Singh
School of Mechanical Engineering
Purdue University
ME315 Heat and Mass Transfer
Exam
#1
Wednesday, September 22, 2010
Instructions:
Write your name on each page
Closedbook exam – a list of equations is given
Please write legibly and show all work for your own benefit. Write on one side
of the page only.
Keep all pages in order
You are asked to write your assumptions and answers to subproblems in
designated areas. Only the work in its designated area will be graded.
Performance
1
30
2
35
3
35
Total
100
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Problem 1 [30 pts]
Consider a plane wall of thickness 100 mm and thermal conductivity 2 W/mK shown below.
One side of the wall is perfectly insulated.
The other side of the wall is exposed to surrounding
air at temperature 25
C and convective heat transfer coefficient of 10 W/m
2
K.
The radiative
heat loss from the same side to surrounding air is 400 W/m
2
.
There is uniform volumetric heat
generation of 10,000 W/m
3
in the wall.
3
W
q = 10,000
m
Assume that conduction through the wall is onedimensional and at steadystate.
(a)
Calculate the temperature (
C) of the wall surface exposed to the surrounding air.
(b)
Write the differential equation and the necessary boundary conditions to obtain
temperature distribution T(x) through the wall. Start with the generalized heat diffusion
equation in rectangular coordinate system. Solve the differential equation to obtain T(x).
List your assumptions here [3 pts]:
Steadystate
Onedimensional conduction in the wall
Constant Properties
Uniform convective heat transfer coefficient on the surface
Start your answer to part (a) here [10 pts]:
Consider energy balance at the surface:
in
out
gen
st
conv
rad
E
EE
E
q
V
q
q
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This note was uploaded on 02/09/2012 for the course ME 352 taught by Professor Staff during the Fall '08 term at Purdue University.
 Fall '08
 Staff
 Mechanical Engineering

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