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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Chapter 3, Problem 3.78P
To determine
An expression for the radial temperature distribution and find the heat rate which must be supplied to maintain a given temperature range.
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Q1
For one -dimension heat transfer conduction consider a shielding wall for a nuclear
reactor. The wall receives a gamma-ray flux such that heat is generated within the
wall according to the relation
9x = 4, ( 2X+3)
Where q0 is the heat generation at the inner face of the wall exposed to the
ray Flux. Using this relation for heat generation, derive an expression for the
temperature distribution in a wall of thickness L, where the inside and outside
temperatures are maintained at Ti and TO, respectively. Also, obtain temperature in
the wall at X= 0.1 m. Assume, Ti-100 °C, TO=200 °C, L= 0.2 m, K = 40 w/ m.
°C, and q0 = 50 W
%D
gamma-
%3D
I 90
y FLUX
То
Ti
For one-dimension heat transfer conduction consider a shielding wall for a nuclear
reactor. The wall receives a gamma-ray flux such that heat is generated within the
wall according to the relation
9x = 90 (2X+3)
Where q0 is the heat generation at the inner face of the wall exposed to the gamma-
ray Flux. Using this relation for heat generation, derive an expression for the
temperature distribution in a wall of thickness L, where the inside and outside
temperatures are maintained at Ti and 70, respectively. Also, obtain temperature in
the wall at X= 0.1 m. Assume, Ti-100 °C, T0-200 °C, L= 0.2 m, K = 40 w / m.
°C, and q0 = 50 W
To
X-
1 90
Y FLUX
Ti
Determine the time needed to decrease the temperature of a solid cylinder from 40 C to 35 C if the ambient temperature is equal to 31 C.
The cylinder has a length equals to 0.9 m and diameter equals to 100 mm. The heat convective coefficient is equal to 1.3 W/m^2.K. The
cylinder has a conductivity equals to 2 W/m.K, a density equals to 1200 kg/m^3 and its Cp is equal to 4.700 kJ/kgK.
Select one:
a. 83325 s
O b. 10500s
O c. 45360 s
O d. 30050 s
Chapter 3 Solutions
Fundamentals of Heat and Mass Transfer
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