Heat And Mass Transfer
5th Edition
ISBN: 9781259173301
Author: Çengel, Yunus A., Ghajar, Afshin J. (afshin Jahanshahi)
Publisher: Mcgraw Hill Education,
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Chapter 2, Problem 30P
Consider a medium in which the heat conduction equation is given in its simplest form as
- Is heat transfer steady or transient?
- Is heat transfer one- two-, or three-dimensional?
- Is there heat generation in the medium?
- Is the thermal conductivity of the medium constant or variable?
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1-D, steady-state conduction with uniform internal energy generation occurs in a plane wall with
a thickness of 50 mm and a constant thermal conductivity of 5 W/m/K. The temperature
distribution has the form T = a + bx + cx² °C. The surface at x=0 has a temperature of To =
120 °C and experiences convection with a fluid for which T..
surface at x= 50 mm is well insulated (no heat transfer). Find:
(a) The volumetric energy generation rate q. (15)
(b) Determine the coefficients a, b, and c.
20 °C and h 500 W/m² K. The
To:
= 120°C
T = 20°C
h = 500 W/m².K
111
Fluid
T(x)-
=
q, k = 5 W/m.K
L = 50 mm
Consider a heat conductor in the form of a long cylinder, with inner and
outer radii R1 and R2, respectively. Heat is generated within the cylinder,
where the temperature O(r, t) at position r and time t satisfies the modified
heat equation
= DV0 + H,
where D is the thermal diffusivity, and H is proportional to the rate of heat
production. The inner and outer surfaces of the cylinder are cooled by a fluid
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(a) If the temperature is in a steady state and depends only on the
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Chapter 2 Solutions
Heat And Mass Transfer
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