144
CHAPTER 5
HEAT-TRANSFER FUNDAMENTALS
G. P. Peterson
Rensselaer Polytechnic Institute
Troy, New York
1 CONDUCTION HEAT TRANSFER 146
1.1 Thermal Conductivity
147
1.2 One-Dimensional Steady-State
Heat Conduction
148
1.3 Two-Dimensional Steady-State
Heat Conduction
155
1.4 Heat Conduction with Convection
Heat Transfer on the Boundaries
156
1.5 Transient Heat Conduction
160
1.6 Conduction at the Microscale
164
2 CONVECTION HEAT TRANSFER 167
2.1 Forced Convection—Internal
Flow
167
2.2 Forced Convection—External
Flow
169
2.3 Free Convection
174
2.4 The Log-Mean Temperature
Difference
176
3 RADIATION HEAT TRANSFER
177
3.1 Blackbody Radiation
178
3.2 Radiation Properties
180
3.3 Configuration Factor
186
3.4 Radiative Exchange among
Diffuse-Gray Surfaces in
an Enclosure
190
3.5 Thermal Radiation Properties
of Gases
193
4 BOILING AND CONDENSATION
HEAT TRANSFER
197
4.1 Boiling
198
4.2 Condensation
201
4.3 Heat Pipes
203
REFERENCES
209
BIBLIOGRAPHY
210
SYMBOLS AND UNITS
A
area of heat transfer
Bi
Biot Number, hL/k, dimensionless
C
circumference, m, constant defined in text
Cp
specific heat under constant pressure, J /kg K
D
diameter, m
e
emissive power, W/m2
f
drag coefficient, dimensionless
F
cross flow correction factor, dimensionless
Fi-j
configuration factor from surface i to surface j, dimensionless
Fo
Fourier Number, tA2 /V 2, dimensionless
Fo-T
radiation function, dimensionless
G
irradiation, W/m2; mass velocity, kg/m2 s
g
local gravitational acceleration, 9.8 m/s2
gc
proportionality constant, 1 kg m/N s2
Gr
Grashof number, gL3T /v2 dimensionless
h
convection heat transfer coefficient, equals q/AT, W/m2 K
hfg
heat of vaporization, J /kg
J
radiosity, W/m2
k
thermal conductivity, W/m K
K
wick permeability, m2
L
length, m
Ma
Mach number, dimensionless
N
screen mesh number, m1
Mechanical Engineers’ Handbook: Energy and Power, Volume 4, Third Edition.
Edited by Myer Kutz
Copyright
2006 by John Wiley & Sons, Inc.
Heat-Transfer Fundamentals
145
Nu
Nusselt number, NuL hL /k, NuD hD /k, dimensionless
Nu
N