Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470501979
Author: Frank P. Incropera, David P. DeWitt, Theodore L. Bergman, Adrienne S. Lavine
Publisher: Wiley, John & Sons, Incorporated
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Textbook Question
Chapter 2, Problem 2.30P
The steady-state temperature distribution in a one-dimensional wall of thermal conductivity
- What is the heat generation rate
- Determine the heat fluxes at the two wall faces. In what manner are these heat fluxes related to the heat generation rate?
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One-dimensional heat transfer through a composite wall is shown in the following
figure. Please calculate the heat flow through the composite wall according to the equivalent
thermal circuit. It is known that the thermal conductivity are ka=46.5 W/(m.K), kp=1.1 W/(m.K),
kc =0.06 W/(m.K), respectively. The thickness of the three materials is Ax,=Axg=Axc=10mm. The
temperature of wall 1 and wall 4 are t=80°C, t4=15°C, respectively. (Please give the compution
process and the result.)
A
- Temperature
profile
RA
Rg
Rc
T3 Axc
A B
1
4
Figure for question 9
PROBLEM 3
In the given schematic of heat transfer for a wall, there is heat conduction through the wall
and the outer surface of the wall is subject to both convection and radiation.
T₁ = 308 K
k = 0.3 W/m-K
L = 3 mm
-T₁
-ε = 0.95
111
Air
Tsur = 297 K
T = 297 K
h = 2 W/m² K (Air)
(a) Write the energy conservation equation for the system in terms of the three heat
transfer modes.
(b) Find the surface temperature Ts in °C.
Derive the general heat conduction equation in Cartesian coordinates. b) Electric heater wires are installed in a solid wall having a thickness of 8 cm and k =2.5W/m ◦C.The right face is exposed to an environment with h=50W/m2◦C and T∞ = 30°C, while the left face is exposed to h=75W/m2◦C and T∞ =50◦C. What is the maximum allowable heat-generation rate such that the maximum temperature in the solid does not exceed 300◦C?
Chapter 2 Solutions
Fundamentals of Heat and Mass Transfer
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