PROBLEM 2.8
KNOWN: One-dimensional system with prescribed thermal conductivity and thickness.
FIND: Unknowns for various temperature conditions and sketch distribution.
SCHEMATIC:
ASSUMPTIONS: (1) Steady-state conditions, (2) One-dimensional conduction, (
PROBLEM 1.5
KNOWN: Inner and outer surface temperatures of a glass window of prescribed dimensions.
FIND: Heat loss through window.
SCHEMATIC:
ASSUMPTIONS: (1) One-dimensional conduction in the x-direction, (2) Steady-state
conditions, (3) Constant proper
PROBLEM 4.42.FAM
GIVEN:
A gridded silicon electric heater is used in a microelectromechanical device, as shown in Figure Pr.4.42.
The heater has an electrical resistance Re and a voltage is applied resulting in the Joule heating. For
testing purposes, the
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PROBLEM 3.50.FAM
GIVEN:
During solidication, as in casting, the melt may locally drop to temperatures below the solidication temperature Tls , before the phase change occurs. Then the melt is in a metastable state (called supercooled liquid)
and the nucle
PROBLEM 6.6
6.9
KNOWN: Variation of local convection coefficient with distance x from a heated plate with a
uniform temperature Ts.
FIND: (a) An expression for the average coefficient h12 for the section of length (x2 - x1) in terms of
C, x1 and x2, and (
PROBLEM 1.62
KNOWN: Duct wall of prescribed thickness and thermal conductivity experiences prescribed heat flux
q at outer surface and convection at inner surface with known heat transfer coefficient.
o
FIND: (a) Heat flux at outer surface required to mai
PROBLEM 3.27
KNOWN: Operating conditions for a board mounted chip.
FIND: (a) Equivalent thermal circuit, (b) Chip temperature, (c) Maximum allowable heat dissipation for
dielectric liquid (ho = 1000 W/m2K) and air (ho = 100 W/m2K). Effect of changes in ci
PROBLEM 3.110
KNOWN: Temperature sensing probe of thermal conductivity k, length L and diameter D is mounted
on a duct wall; portion of probe Li is exposed to water stream at T,i while other end is exposed to
ambient air at T,o ; convection coefficients h
PROBLEM 8.8
8.9
KNOWN: Velocity and temperature profiles for laminar flow in a parallel plate channel.
FIND: Mean velocity, um, and mean (or bulk) temperature, Tm, at this axial position. Plot the velocity
and temperature distributions. Comment on whether
PROBLEM 6.7
KNOWN: Radial distribution of local convection coefficient for flow normal to a circular
disk.
FIND: Expression for average Nusselt number.
SCHEMATIC:
ASSUMPTIONS: Constant properties
ANALYSIS: The average convection coefficient is
1
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PROBLEM 2.21
KNOWN: Diameter D, thickness L and initial temperature Ti of pan. Heat rate from stove to bottom
of pan. Convection coefficient h and variation of water temperature T(t) during Stage 1.
Temperature TL of pan surface in contact with water duri
ME 335 (HEAT TRANSFER), FALL 2013, EXAM II
OPEN BOOK, 2 SHEETS OF HAND WRITTEN NOTES
Department of Mechanical Engineering, University of Michigan
Name:
Pledge:
PROBLEM 1 (35%)
Hot-wire anemometer is used to measure the fluid velocity uf, , as shown in Fig
PROBLEM 2.5
KNOWN: End-face temperatures and temperature dependence of k for a truncated cone.
FIND: Variation with axial distance along the cone of q x , q , k, and dT / dx.
x
SCHEMATIC:
ASSUMPTIONS: (1) One-dimensional conduction in x (negligible temper
PROBLEM 8.32
8.33
KNOWN: Flow rate, inlet temperature and desired outlet temperature of water passing through a tube of
prescribed diameter and surface temperature.
FIND: (a) Required tube length, L, for prescribed conditions, (b) Required length using tu
PROBLEM 12.20
12.18
2
KNOWN: Solar flux at outer edge of earths atmosphere, 1353 W/m .
FIND: (a) Emissive power of sun, (b) Surface temperature of sun, (c) Wavelength of maximum solar
emission, (d) Earth equilibrium temperature.
SCHEMATIC:
ASSUMPTIONS: (1
PROBLEM 3.118
KNOWN: Extended surface of rectangular cross-section with heat flow in the longitudinal direction.
FIND: Determine the conditions for which the transverse (y-direction) temperature gradient is
negligible compared to the longitudinal gradient
ME 335 (HEAT TRANSFER), WINTER 2013, EXAM II
OPEN BOOK, 2 SHEETS OF HAND WRITTEN NOTES
Department of Mechanical Engineering, University of Michigan
Name:
Pledge:
PROBLEM 1 (35%)
A rectangular-shaped radiant heater (surface 1) using Joule heating (S e,J )1
ME 335 (HEAT TRANSFER), WINTER 2014, EXAM II
OPEN BOOK, 2 SHEETS OF HAND WRITTEN NOTES
Department of Mechanical Engineering, University of Michigan
PROBLEM 1 (33%)
GIVEN:
A disk of diameter D is electrically (Joule) heated at a rate of S e,J and its radia
ME 335 (HEAT TRANSFER), FALL 2013, EXAM I
OPEN BOOK, 2 SHEETS OF HAND WRITTEN NOTES
Department of Mechanical Engineering, University of Michigan
Name:
Pledge:
PROBLEM 1 (35%)
Consider cooling of human body by sweating. The average human surface area is 1.
ME 335 (HEAT TRANSFER), FALL 2013, EXAM I
OPEN BOOK, 2 SHEETS OF HAND WRITTEN NOTES
Department of Mechanical Engineering, University of Michigan
Name:
Pledge:
PROBLEM 1 (35%)
Consider cooling of human body by sweating. The average human surface area is 1.
ME 335 (HEAT TRANSFER), WINTER 2014, EXAM I
OPEN BOOK, 2 SHEETS OF HAND WRITTEN NOTES
Department of Mechanical Engineering, University of Michigan
PROBLEM 1 (33%)
In a transistor shown in Figure Pr.1(i), Joule heating occurs along the electron flow path a
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3.32
3.34
(3) Obtain an expression for the temperature distribution
T(x).
(b) What is the rate of heat transfer across the cone if it
is constructed of pure aluminum with x1 = 0.075 m,
T. : 100C,x2 = 0.225 m, and T2 = 20C?
From Figure 2.5 it is e
ME 335 (HEAT TRANSFER), FALL 2012, EXAM II
OPEN BOOK, 2 SHEETS OF HAND WRITTEN NOTES
Department of Mechanical Engineering, University of Michigan
Name:
Pledge:
PROBLEM 1 (33%)
The ice rink in hockey arena is heated by surface convection (assume thermobuoy
ME 335 (HEAT TRANSFER), FALL 2015, EXAM II, SOLUTION
Department of Mechanical Engineering, University of Michigan
PROBLEM 1 (35%)
GIVEN:
Two blackbody parallel disk surfaces of radius R are separated by a distance l. The disks are at temperatures
T1 and T