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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Sprache: Englisch
Whether in a solar thermal power plant or at the heart of a nuclear reactor, convection is an important mode of energy transfer. This mode is unique; it obeys specific rules and correlations that constitute one of the bases of equipment-sizing equations. In addition to standard aspects of convention, this book examines transfers at very high temperatures where, in order to ensure the efficient transfer of energy for industrial applications, it is becoming necessary to use particular heat carriers, such as molten salts, liquid metals or nanofluids. With modern technologies, these situations are becoming more frequent, requiring appropriate consideration in design calculations. Energy Transfers by Convection also studies the sizing of electronic heat sinks used to ensure the dissipation of heat and thus the optimal operation of circuit boards used in telecommunications, audio equipment, avionics and computers.
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Veröffentlichungsjahr: 2019
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Table of Contents
Cover
Preface
Introduction
1 Methods for Determining Convection Heat Transfer Coefficients
1.1. Introduction
1.2. Characterizing the motion of a fluid
1.3. Transfer coefficients and flow regimes
1.4. Using dimensional analysis
1.5. Using correlations to calculate
h
2 Forced Convection inside Cylindrical Pipes
2.1. Introduction
2.2. Correlations in laminar flow
2.3. Correlations in transition zone
2.4. Correlations in turbulent flow
2.5. Dimensional correlations for air and water
3 Forced Convection inside Non-cylindrical Pipes
3.1. Introduction
3.2. Concept of hydraulic diameter
3.3. Hydraulic Nusselt and Reynolds numbers
3.4. Correlations in established laminar flow
3.5. Correlations in turbulent flow for non-cylindrical pipes
4 Forced Convection outside Pipes or around Objects
4.1. Introduction
4.2. Flow outside a cylindrical pipe
4.3. Correlations for the stagnation region
4.4. Correlations beyond the stagnation zone
4.5. Forced convection outside non-cylindrical pipes
4.6. Forced convection above a horizontal plate
4.7. Forced convection around non-cylindrical objects
4.8. Convective transfers between falling films and pipes
4.9. Forced convection in coiled pipes
5 Natural Convection Heat Transfer
5.1. Introduction
5.2. Characterizing the motion of natural convection
5.3. Correlations in natural convection
5.4. Vertical plates subject to natural convection
5.5. Inclined plates subject to natural convection
5.6. Horizontal plates subject to natural convection
5.7. Vertical cylinders subject to natural convection
5.8. Horizontal cylinders subject to natural convection
5.9. Spheres subject to natural convection
5.10. Vertical conical surfaces subject to natural convection
5.11. Any surface subject to natural convection
5.12. Chambers limited by parallel surfaces
5.13. Inclined-plane chambers
5.14. Chambers limited by two concentric cylinders
5.15. Chambers limited by two concentric spheres
5.16. Simplified correlations for natural convection in air
5.17. Finned surfaces: heat sinks in electronic systems
5.18. Optimizing the thermal resistance of a heat sink
5.19. Optimum circuit-board assembly
5.20. Superimposed forced and natural convections
6 Convection in Nanofluids, Liquid Metals and Molten Salts
6.1. Introduction
6.2. Transfers in nanofluids
6.3. Transfers in liquid metals
6.4. Transfers in molten salts
6.5. Reading: Eugène Péclet and Lord Rayleigh
7 Exercises and Solutions
Appendices
Appendix 1 Database
Appendix 2 Regressions
Bibliography
Index
End User License Agreement
List of Tables
Chapter 2
Table 2.1.
Variations in the heat transfer coefficient according to the distance...
Table 2.2.
Calculating the heat transfer coefficient according to the distance w...
Table 2.3.
Determining h for different flow rates
Table 2.4.
Calculation of heat transfer coefficient for different flow rates
Table 2.5.
Pipe roughnesses factor
Chapter 3
Table 3.1.
for rectangular or square pipes
Table 3.2.
Nu
H
for elliptical pipes
Table 3.3.
Nu
H
for triangular pipes
Table 3.4.
Configurations considered
Table 3.5.
Flow regimes for rectangular pipes
Table 3.6.
Flow regimes for elliptical pipes
Table 3.7.
Heat transfer coefficients for the two configurations
Table 3.8.
Data relating hot and cold fluids
Table 3.9.
Dimensions of the rectangular and elliptical pipes
Table 3.10.
Determining the flow regimes
Table 3.11.
Calculating the heat transfer coefficients
Table 3.12.
Comparison of results
Table 3.13.
Data relating to oil and water
Chapter 4
Table 4.1.
Values of constants
C
and
M
for flow through a cylindrical pipe
Chapter 5
Table 5.1.
Parameters C and n (*hot plate located at the bottom)
Table 5.2.
Critical inclinations
Table 5.3.
Examples of thermal resistances in electronic heat sinks
Table 5.4.
Physical properties of air at different temperatures
Table 5.5.
Physical properties of air between 30 and 60°C
Table 5.6.
Calculating the operating temperature
Table 5.7.
Factors and for the Martinelli-Boelter correlation
Chapter 6
Table 6.1.
Approximate particle size
Table 6.2.
Comparison of thermal conductivities
Table 6.3.
Fusion and boiling temperatures and heat conductivities of several me...
Table 6.4.
Physical properties of HTS
Table 6.5.
Draw salt and HTS compositions and fields of application
Appendix 1
Table A1.1.
Densities for metals and alloys (kg/m
3
)
Table A1.2.
Densities for construction materials (kg/m
3
)
Table A1.3.
Densities of different thermal insulation materials (in kg/m
3
)
Table A1.4.
Sensible heats for metals and alloys (J kg
-1
°C)
Table A1.5.
Sensible heats for certain construction materials (J kg
-1
°C)
Table A1.6.
Sensible heats of certain thermal insulation materials
Table A1.7.
Heat conductivities (metals and alloys)
Table A1.8.
Heat conductivities (construction materials)
Table A1.9.
Conductivities of certain thermal insulation materials
Table A1.10.
Physical data and mechanical properties of heat insulators
Table A1.11.
Density (ρ), sensible heat (Cp), thermal conductivity (λ), thermal ...
Table A1.12.
Density(ρ), sensible heat (Cp), thermal conductivity (λ), thermal d...
Table A1.13.
(ω1 solutions according to the Biot number, for planar, cylindrical...
Table A1.14.
Aω1 coefficients according to the Biot number for planar, cylindric...
Table A1.15.
Evolution of the function
Γ
for the first natural numbers
Table A1.16.
Molar composition of FLiNaK
Table A1.17.
Density of FLiNaK according to temperature (T is expressed in K, ρ ...
Table A1.18.
Viscosity of FLiNaK according to temperature (T is expressed in K, ...
Table A1.19.
Viscosity of FLiNaK according to temperature (T is expressed in K, ...
Table A1.20.
Physical properties of FLiNaK according to temperature
Table A1.21.
Molar composition of FLiBe
Table A1.22.
Density of FLiBe as a function of temperature (T is expressed in K,...
Table A1.23.
Physical properties of FLiBe according to temperature
Table A1.24.
Physical properties of KMgCl according to temperature
Table A1.25.
Molar composition of NaNOK
Table A1.26.
Thermal conductivities of NaNOK
Table A1.27.
Physical properties of NaNOK according to temperature
Table A1.28.
Unit conversion table
Table A1.29.
Fundamental constant values
List of Illustrations
Chapter 1
Figure 1.1.
Flow regimes
Figure 1.2.
Determining flow regime
Figure 1.3.
Laminar and turbulent convective fluxes
Figure 1.4.
Deetermining the convective flux
Chapter 2
Figure 2.1.
Cylindrical pipe of length L
.
For a color version of this figure
, se...
Figure 2.2.
Volume element
.
For a color version of this figure
, see www.iste.co....
Figure 2.3.
Volume element of fluid between x and
x + dx. For a color version of...
Figure 2.4.
Differential fluid element
.
For a color version of this figure
, see ...
Chapter 3
Figure 3.1.
Pipe presenting a rectangular cross-section area
Figure 3.2.
Pipe presenting an elliptical cross-section area
Figure 3.3.
Pipe presenting a triangular cross-section area
Figure 3.4.
Circulation in an annular pipe. For a color version of this figure, ...
Figure 3.5.
Evolution of the Nusselt number with the ratio D1/D2, for an annular...
Figure 3.6.
Evolution of the Nusselt number with the ratio D1/D2 for an annular ...
Figure 3.7.
Triangular pipe
Figure 3.8.
Elliptical pipe
Chapter 4
Figure 4.1.
Multi-tube heat exchanger. For a color version of this figure, see w...
Figure 4.2.
Flow outside a pipe: v∞. is in fact the flow velocity far from the p...
Figure 4.3.
Straight square
Figure 4.4.
Inclined square
Figure 4.5.
Ellipse
Figure 4.6.
Hexagonal cross-section with two horizontal sides
Figure 4.7.
Hexagonal cross-section with two vertical sides
Figure 4.8.
Horizontal plate
Figure 4.9.
Plate with constant flow density. For a color version of this figure...
Figure 4.10.
Forced convection around a plane parallel to the flow
Figure 4.11.
Forced convection around a sphere
Figure 4.12.
Coil tank. For a color version of this figure, see www.iste.co.uk/b...
Figure 4.13.
Turbine with blade disk
Figure 4.14.
Straight-blade turbine
Chapter 5
Figure 5.1.
Natural convection. For a color version of this figure, see www.iste...
Figure 5.2.
Vertical plate. For a color version of this figure, see www.iste.co....
Figure 5.3.
Inclined plate. For a color version of this figure, see www.iste.co....
Figure 5.4.
Underfloor heating. For a color version of this figure, see www.iste...
Figure 5.5.
Cooling from the top. For a color version of this figure, see www.is...
Figure 5.6.
Vertical cylinder. For a color version of this figure, see www.iste....
Figure 5.7.
Horizontal cylinder. For a color version of this figure, see www.ist...
Figure 5.8.
Immersed sphere. For a color version of this figure, see www.iste.co...
Figure 5.9.
Immersed cone. For a color version of this figure, see www.iste.co.u...
Figure 5.10.
Fluid between two horizontal plates. For a color version of this fi...
Figure 5.11.
Fluid between two vertical plates. For a color version of this figu...
Figure 5.12.
Inclined chamber. For a color version of this figure, see www.iste....
Figure 5.13.
Inclined chamber
Figure 5.14.
Inclined chamber
Figure 5.15.
Transistor on heat sink assembly
Figure 5.16.
Different models of heat sinks for electronic assemblies
Figure 5.17.
Simplified electrical representation of heat transfer between a hea...
Figure 5.18.
Detailed electrical representation of heat transfer between an elec...
Figure 5.19.
Details of the heat-sink fins
Figure 5.20.
Algorithm to optimize the surface of a heat sink
Figure 5.21.
Positioning of circuit boards on a rack. For a color version of thi...
Figure 5.22.
Optimization of electronic board installation on racks
Figure 5.23.
Natural and forced convections in a vertical tube. For a color vers...
Figure 5.24.
Natural and forced convections in a horizontal tube. For a color ve...
Figure 5.25.
Rotating cylinder
Figure 5.26.
Disk in rotation
Figure 5.27.
Sphere in rotation
Chapter 6
Figure 6.1.
Flow on a plate. For a color version of this figure, see www.iste.co...
Figure 6.2.
Eugène Péclet (1793–1857)
Figure 6.3.
John William Strutt, Lord Rayleigh (1842–1919)
Appendix 1
Figure A1.1.
Bessel function of order 0
Figure A1.2.
Bessel function of order 1
Guide
Cover
Table of Contents
Begin Reading
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Energy Engineering Set
coordinated byAbdelhanine Benallou
Volume 3
Energy Transfers by Convection
Abdelhanine Benallou
First published 2019 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:
ISTE Ltd
27–37 St George’s Road
London SW19 4EU
UK
www.iste.co.uk
John Wiley & Sons, Inc.
111 River Street
Hoboken, NJ 07030
USA
www.wiley.com
© ISTE Ltd 2019
The rights of Abdelhanine Benallou to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.
Library of Congress Control Number: 2018962094
British Library Cataloguing-in-Publication Data
A CIP record for this book is available from the British Library
ISBN 978-1-78630-276-2
Preface
“The secret of change is to focus all your energy not on fighting the old, but on building the new.”
Dan Millman (1946–), artist, author, record-holder and sportsman
For several years, I have cherished the wish of devoting enough time to the writing of a series of books on energy engineering. The reason is simple: for having practiced for years teaching as well as consulting in different areas ranging from energy planning to rational use of energy and renewable energies, I have always noted the lack of formal documentation in these fields to constitute a complete and coherent source of reference, both as a tool for teaching to be used by engineering professors and as a source of information summarizing, for engineering students and practicing engineers, the basic principles and the founding mechanisms of energy and mass transfers leading to calculation methods and design techniques.
But between the teaching and research tasks (first as a teaching assistant at the University of California and later as a professor at the École des mines de Rabat, Morocco) and the consulting and management endeavors conducted in the private and in the public sectors, this wish remained for more than twenty years in my long list of priorities, without having the possibility to make its way up to the top. Only providence was able to unleash the constraints and provide enough time to achieve a lifetime objective.
This led to a series consisting of nine volumes:
–
Volume 1:
Energy and Mass Transfers;
–
Volume 2:
Energy Transfers by Conduction;
–
Volume 3:
Energy Transfers by Convection;
–
Volume 4:
Energy Transfers by Radiation;
–
Volume 5:
Mass Transfers and Physical Data Estimation;
–
Volume 6:
Design and Calculation of Heat Exchangers;
–
Volume 7:
Solar Thermal Engineering;
–
Volume 8:
Solar Photovoltaic Energy Engineering;
–
Volume 9:
Rational Energy Use Engineering.
The present book is the third volume of this series. It concerns the study of convection heat transfer.
As we will see, the calculation methods established in this book present multiple applications in engineering: heat exchanger calculation, demand-side energy, improvement of heat dissipation in electronic circuits, etc.
A series of exercises is presented at the end of the book, aimed at enabling students to implement new concepts as rapidly as possible. These exercises are designed to correspond as closely as possible to real-life situations occurring in industrial practice or everyday life.
Abdelhanine BENALLOU October 2018
