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ME 324
HW #1
21.02.2011
1.
A square isothermal chip is of width
w
= 5 mm on a side and is mounted in a substrate such that
its side and back surfaces are well insulated, while the front surface is exposed to the flow of a
coolant at
T
= 20 ºC. From the reliability consideration, the chip temperature must not exceed
T
= 85ºC.
(1)
If the coolant is air and the corresponding convection coefficient is
h
= 200 W/m
2
K, what is
the maximum allowable chip power?
(2)
If the coolant is a dielectric liquid for which
h
= 3000 W/m
2
K, what is the maximum
allowable power?
w
= 5 mm
Coolant
chip
2.
A sphere 4.0 cm in diameter is heated to a temperature of 150ºC and is enclosed in a large room at
20ºC. Air in the room is also at 20ºC. The average convection heat transfer coefficient is 9.8
W/m
2
K. The surface emissivity of the sphere is 0.65. Calculate the total heat loss due to both
convection and radiation.
3.
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This note was uploaded on 10/05/2011 for the course ME me352 taught by Professor Koraykadirsafak during the Spring '11 term at Yeditepe Üniversitesi.
 Spring '11
 koraykadirsafak

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