Burton T. (et. al.) Wind energy Handbook
Подождите немного. Документ загружается.
WIND ENERGY
HANDBOOK
WIND ENERGY
HANDBOOK
Tony Burton
Wind Energy Consultant, Carno, UK
David Sharpe
CREST, Loughborough University, UK
Nick Jenkins
UMIST, Manchester, UK
Ervin Bossanyi
Garrad Hassan & Partners, Bristol, UK
JOHN WILEY & SONS, LTD
Chichester • New York • Weinheim • Brisbane • Singapore • Toronto
Copyright # 2001 by John Wiley & Sons, Ltd
Baffins Lane, Chichester
West Sussex, PO19 1UD, England
National 01243 779777
International (þ44) 1243 779777
e-mail (for orders and customer service enquiries): cs-books@wiley.co.uk
Visit our Home Page on: http://www.wiley.co.uk or http://www.wiley.com
All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, scanning or
otherwise, except under the terms of the Copyright Designs and Patents Act 1988 or under the terms of a
licence issued by the Copyright Licensing Agency, 90 Tottenham Court Road, London, W1P 9HE, UK,
without the permission in writing of the Publisher, with the exception of any material supplied
specifically for the purpose of being entered and executed on a computer system, for exclusive use by the
purchaser of the publication.
Neither the authors nor John Wiley & Sons Ltd accept any responsibility or liability for loss or damage
occasioned to any person or property through using the material, instructions, methods or ideas
contained herein, or acting or refraining from acting as a result of such use. The authors and Publisher
expressly disclaim all implied warranties, including merchantability of fitness for any particular purpose.
There will be no duty on the authors of Publisher to correct any errors or defects in the software.
Designations used by companies to distinguish their products are often claimed as trademarks. In all
instances where John Wiley & Sons is aware of a claim, the product names appear in initial capital or
capital letters. Readers, however, should contact the appropriate companies for more complete
information regarding trademarks and registration.
Other Wiley Editorial Offices
John Wiley & Sons, Inc., 605 Third Avenue,
New York, NY 10158-0012, USA
Wiley-VCH Verlag GmbH,
Pappelallee 3, D-69469 Weinheim, Germany
John Wiley, Australia, Ltd, 33 Park Road, Milton,
Queensland 4064, Australia
John Wiley & Sons (Canada) Ltd, 22 Worcester Road,
Rexdale, Ontario, M9W 1L1, Canada
John Wiley & Sons (Asia) Pte Ltd, 2 Clementi Loop #02-01,
Jin Xing Distripark, Singapore 129809
Library of Congress Cataloguing-in-Publication Data
Handbook of wind energy / Tony Burton ...[et al.].
p. cm.
Includes bibliographical references and index.
ISBN 0-471-48997-2
1. Wind power — Handbooks, manuals, etc. I. Burton, Tony, 1947-
TJ820.H35 2001
621.31’2136–dc21 2001024908
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
ISBN 0 471 48997 2
Typeset in 10/12pt Palatino by Keytec Typesetting Ltd, Bridport, Dorset
Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire
This book is printed on acid-free paper responsibly manufactured from sustainable forestry,
in which at least two trees are planted for each one used for paper production.
Contents
Acknowledgements xv
List of symbols xvii
1 Introduction 1
1.1 Historical Development 1
1.2 Modern Wind Turbines 6
1.3 Scope of the Book 7
References 8
Bibliography 9
2 The Wind Resource 11
2.1 The Nature of the Wind 11
2.2 Geographical Variation in the Wind Resource 12
2.3 Long-term Wind-speed Variations 13
2.4 Annual and Seasonal Variations 14
2.5 Synoptic and Diurnal Variations 16
2.6 Turbulence 17
2.6.1 The nature of turbulence 17
2.6.2 The boundary layer 18
2.6.3 Turbulence intensity 21
2.6.4 Turbulence spectra 22
2.6.5 Length scales and other para meters 23
2.6.6 Cross-spectra and coherence functions 26
2.7 Gust Wind Speeds 29
2.8 Extreme Wind Speeds 30
2.8.1 Extreme winds in standards 31
2.9 Wind-speed Prediction and Forecasting 33
2.9.1 Statistical methods 33
2.9.2 Meteorological methods 34
2.10 Turbulence in Wakes and Wind Farms 35
2.11 Turbulence in Complex Terrain 37
References 38
3 Aerodynamics of Horizontal-axis Wind Turbines 41
3.1 Introduction 41
3.2 The Actuator Disc Concept 42
3.2.1 Momentum theory 43
3.2.2 Power coefficient 44
3.2.3 The Betz limit 45
3.2.4 The thrust coefficient 46
3.3 Rotor Disc Theory 46
3.3.1 Wake rotation 47
3.3.2 Angular moment um theory 47
3.3.3 Maximum power 49
3.3.4 Wake structure 50
3.4 Vortex Cylinder Model of the Actuator Disc 51
3.4.1 Introduction 51
3.4.2 Vortex cylinder theory 52
3.4.3 Relationship between bound circulation and the induced velocity 53
3.4.4 Root vortex 54
3.4.5 Torque and power 55
3.4.6 Axial flow field 56
3.4.7 Tangential flow field 57
3.4.8 Radial flow field 58
3.4.9 Conclusions 59
3.5 Rotor Blade Theory 59
3.5.1 Introduction 59
3.5.2 Blade element theory 60
3.5.3 The blade element – momentum (BEM) theory 61
3.5.4 Determination of rotor torque and power 64
3.6 Breakdown of the Momentum Theory 65
3.6.1 Free-stream/wake mixing 65
3.6.2 Modification of rotor thrust caused by flow separ ation 66
3.6.3 Empirical determination of thrust coefficient 67
3.7 Blade Geometry 68
3.7.1 Introduction 68
3.7.2 Optimal design for variable-speed operation 68
3.7.3 A practical blade design 73
3.7.4 Effects of drag on optimal blade design 75
3.7.5 Optimal blade design for constan t-speed operation 77
3.8 The Effects of a Discrete Number of Blades 78
3.8.1 Introduction 78
3.8.2 Tip losses 78
3.8.3 Prandtl’s appro ximation for the tip-loss factor 83
3.8.4 Blade root losses 86
3.8.5 Effect of tip loss on optimum blade design and power 87
3.8.6 Incorporation of tip-loss for non-optimal operation 91
3.9 Calculated Results for an Actual Turbine 93
3.10 The Aerodynamics of a Wind Turbine in Steady Yaw 96
3.10.1 Momentum theory for a turbine rotor in steady yaw 96
vi CONTENTS
3.10.2 Glauert’s momentum theory for the yawed rotor 99
3.10.3 Vortex cylinder model of the yawed actuator disc 103
3.10.4 Flow expansion 107
3.10.5 Related theories 112
3.10.6 Wake rotation for a turbine rotor in steady yaw 113
3.10.7 The blade element theory for a turbine rotor in steady yaw 115
3.10.8 The blade element–mome ntum theory for a rotor in steady yaw 116
3.10.9 Calculated values of induced velocity 120
3.10.10 Blade forces for a rotor in steady yaw 121
3.10.11 Yawing and tilting moments in steady yaw 122
3.11 The Method of Acceleration Potential 125
3.11.1 Introduction 125
3.11.2 The general pressure distribution theory 126
3.11.3 The axi-symmetric pressure distributions 129
3.11.4 The anti-symmetric pressure distributions 133
3.11.5 The Pitt and Peters model 136
3.11.6 The general acceleration poten tial method 137
3.11.7 Comparison of methods 137
3.12 Stall Delay 138
3.13 Unsteady Flow – Dynamic Inflow 141
3.13.1 Introduction 141
3.13.2 Adaptation of the acceleration potential method to unsteady flow 142
3.13.3 Unsteady yawing and tilting moments 146
3.13.4 Quasi-steady aerofoil aerodynamics 148
3.13.5 Aerodynamic forces caused by aerofoil acceleration 149
3.13.6 The effect of the wake on aerofoil aerodynamics in unsteady flow 150
References 154
Bibliography 155
Appendix: Lift and Drag of Aerofoils 156
A3.1 Definition of Drag 156
A3.2 Drag Coefficient 159
A3.3 The Boundary Layer 160
A3.4 Boundary-layer Separation 160
A3.5 Laminar and Turbulent Boundary Layers 161
A3.6 Definition of Lift and its Relationship to Circul ation 163
A3.7 The Stalled Aerofoil 166
A3.8 The Lift Coefficient 167
A3.9 Aerofoil Drag Characteristics 168
A3.10 Variation of Aerofoil Charac teristics with Reynolds Number 169
A3.11 Cambered Aerofoils 170
4 Wind-turbine Performance 173
4.1 The Performance Curves 173
4.1.1 The C
P
º performance curve 173
4.1.2 The effect of solidity on performance 174
4.1.3 The C
Q
º curve 176
4.1.4 The C
T
º curve 176
CONTENTS vii
4.2 Constant Rotational Speed Operation 177
4.2.1 The K
P
1=º curve 177
4.2.2 Stall regulation 178
4.2.3 Effect of rotational speed change 179
4.2.4 Effect of blade pitch angle change 180
4.2.5 Pitch regulation 180
4.2.6 Pitching to stall 181
4.2.7 Pitching to feather 181
4.3 Comparison of Measured with Theoretical Performance 182
4.4 Variable-speed Operation 184
4.5 Estimation of Energy Capture 185
4.6 Wind-turbine Field Testing 190
4.6.1 Introduction 190
4.6.2 Information sources for wind-turbine testing 190
4.7 Wind-turbine Performance Measurement 191
4.7.1 Field testing methodology 192
4.7.2 Wind-speed measurement 193
4.7.3 Wind-direction measurement 194
4.7.4 Air temperature and pressure measurement 194
4.7.5 Power measurement 196
4.7.6 Wind-turbine status 196
4.7.7 Data acquisition system 196
4.7.8 Data acquisition rate 197
4.8 Analysis of Test Data 197
4.9 Turbulence Effects 198
4.10 Aerodynamic Performance Assessment 200
4.11 Errors and Uncertainty 204
4.11.1 Evaluation of uncertainty 204
4.11.2 Sensitivity factors 205
4.11.3 Estimating uncertainties 206
4.11.4 Combining uncertainties 206
References 207
5 Design Loads for Horizontal-axis Wind Turbines 209
5.1 National and International Standards 209
5.1.1 Historical development 209
5.1.2 IEC 61400-1 209
5.1.3 Germanisher Lloyd rules for certification 210
5.1.4 Danish Standard DS 472 211
5.2 Basis for Design Loads 211
5.2.1 Sources of loading 211
5.2.2 Ultimate loads 211
5.2.3 Fatigue loads 212
5.2.4 Partial safety factors for loads 212
5.2.5 Functions of the control and safety systems 213
5.3 Turbulence and Wakes 213
viii CONTENTS
5.4 Extreme Loads 214
5.4.1 Non-operational load cases – normal machine state 214
5.4.2 Non-operational load cases – machine fault state 215
5.4.3 Operational load cases – normal machine state 215
5.4.4 Operational load cases – loss of load 217
5.4.5 Operational load cases – machine fault states 218
5.4.6 Start-up and shut-down cases 218
5.4.7 Blade/tower clearance 218
5.5 Fatigue Loading 218
5.5.1 Synthesis of fatigue load spectrum 218
5.6 Stationary Blade Loading 219
5.6.1 Lift and drag coefficients 219
5.6.2 Critical configuration for different machine types 219
5.6.3 Dynamic res ponse 220
5.7 Blade Loads During Operation 228
5.7.1 Deterministic and stochastic load components 228
5.7.2 Deterministic aerodynamic loads 228
5.7.3 Gravity loads 236
5.7.4 Deterministic inertia loads 236
5.7.5 Stochastic aerodynamic loads – analysis in the frequency domain 239
5.7.6 Stochastic aerodynamic loads – analysis in the time domain 249
5.7.7 Extreme loads 252
5.8 Blade Dynamic Response 255
5.8.1 Modal analysis 255
5.8.2 Mode shapes and frequencies 258
5.8.3 Centrifugal stiffen ing 259
5.8.4 Aerodynamic and structural damping 262
5.8.5 Response to deterministic loads—step-by-step dynamic analysis 264
5.8.6 Response to stochastic loads 268
5.8.7 Response to simulated loads 271
5.8.8 Teeter motion 271
5.8.9 Tower coupling 276
5.8.10 Wind turbine dynamic analysi s codes 282
5.8.11 Aeroelastic stability 286
5.9 Blade Fatigue Stresses 287
5.9.1 Methodology for blade fatigue design 287
5.9.2 Combination of deterministic and stochastic components 288
5.9.3 Fatigue pred ictions in the frequency domain 290
5.9.4 Wind simulation 292
5.9.5 Fatigue cycle counting 293
5.10 Hub and Low-speed Shaft Loading 293
5.10.1 Introduction 293
5.10.2 Deterministic aerodynamic loads 294
5.10.3 Stochastic aerodynamic loads 296
5.10.4 Gravity loading 297
5.11 Nacelle Loading 298
5.11.1 Loadings from rotor 298
CONTENTS ix
5.11.2 Cladding loads 299
5.12 Tower Loading 300
5.12.1 Extreme loads 300
5.12.2 Dynamic response to extreme loads 300
5.12.3 Operational loads due to steady wind (determinist ic component) 304
5.12.4 Operational loads due to turbulence (stochastic component) 305
5.12.5 Dynamic response to operational loads 308
5.12.6 Fatigue loads and stresses 309
References 311
Appendix: Dynamic Response of Stationary Blade in Turbulent Wind 313
A5.1 Introduction 313
A5.2 Frequency Respo nse Function 313
A5.2.1 Equation of motion 313
A5.2.2 Frequency response function 314
A5.3 Resonant Displacement Response Ignoring Wind Variations along the
Blade 315
A5.3.1 Linearization of wind loading 315
A5.3.2 First mode displacement response 315
A5.3.3 Background and resonant response 315
A5.4 Effect of Ac-Wind Turbulence Distribution on Resonant Displacement
Response 317
A5.4.1 Formula for normalized co-spectrum 319
A5.5 Resonant Root Bending Moment 320
A5.6 Root Bending Moment Background response 322
A5.7 Peak Response 324
A5.8 Bending Moments at Intermediate Blade Positions 326
A5.8.1 Background response 326
A5.8.2 Resonant response 327
References 327
6 Conceptual Design of Horizontal Axis Wind Turbines 329
6.1 Introduction 329
6.2 Rotor Diameter 329
6.2.1 Cost modelling 330
6.2.2 Simplified cost model for machine size optimization—an illustration 330
6.3 Machine Rating 333
6.3.1 Simplified cost model for optimizing machine rating in relation to
diameter 333
6.3.2 Relationship between optimum rated wind speed and annual mean 336
6.3.3 Specific power of production machines 336
6.4 Rotational Speed 337
6.4.1 Ideal relationship between rotatio nal speed and solidity 338
6.4.2 Influence of rotational speed on blade weight 339
6.4.3 Optimum rotational speed 339
6.4.4 Noise constraint on rotational speed 339
6.4.5 Visual considerations 340
x CONTENTS