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Convec'on Heat Transfer
Convec'on Heat Transfer
Convec've heat transfer is the conduc'on of heat
into a moving uid.
We most o:en model convec'on heat transfer
using a heat transfer coecient h such that:
q = hA(
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Two Dimensional
Steady Conduc4on
Shape Factors
Shape factors are a simple means of accoun4ng for the geometric
factors aec4ng conduc4on in 1D, 2D and 3D systems.
The shape factor S is dened such that:
Q =
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One Dimensional
Steady Conduc3on
1 D Conduc3on Problems
We will examine a number of fundamental
onedimensional solu3ons including:
Plane wall, cylindrical shell, spherical shell
Composite systems, i.e. more than
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Conduc'on Heat Transfer
Conduc'on Equa'on
Fouriers Law
T
qx A
x
Heat ow is propor'onal to temperature
dierence and area, and inversely
propor'onal to distance. In dieren'al
form:
qx = kA
q'x' = k
T
dT
= kA
x
d
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Heat Transfer I
ENGR 6901
Fall, 2012
Dr. Y.S. Muzychka
EN 3058
Course Materials
Course Text:
Fundamentals of Heat and Mass Transfer
Bergman, Levine, Incropera and DeWiS, 7th EdiUon
6th EdiUon is also OK,
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Transient Conduc/on
Transient Conduc/on
Transient conduc/on problems occur when
the temperature eld changes in /me.
We will examine some fundamental problems
in Transient Conduc/on, namely:
Lumped Analysis T(t) onl
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Convec'on Heat Transfer
Natural Convec'on
A Quick Overview of Correla'ons
Convec'on Heat Transfer
Natural Convec'on occurs when a change in
density due to hea'ng of a uid, induces a
mo'on
Frequently other terms
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Convec'on Heat Transfer
External Flows
Convec'on Heat Transfer
External Flows (Chapter 7)
We begin by considering the most
fundamental problem in convec've heat
transfer: The Flat Plate
This is an extension of
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Radia%on Heat Transfer
Radia%on Heat Transfer
We will now consider heat transfer processes
in which thermal radia%on is important.
The simplest problems involve one surface
and a surroundings in which radiant exch
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Convec'on Heat Transfer
Internal Flows
Convec'on Heat Transfer
Internal Convec'on:
We will examine what aects the convec'on heat
transfer coecient.
We will see that the stream temperature can no
longer be consi