Wind Power Generation and Wind Turbine Design WITPRESS WIT Press publishes leading books in Science and Technology Visit our website for the current list of titles www.witpress.com WITeLibrary Home of the Transactions of the Wessex Institute, the WIT electronic-library provides the international scientific community with immediate and permanent access to individual papers presented at WIT conferences Visit the WIT eLibrary at http://library.witpress.com This page intentionally left blank Wind Power Generation and Wind Turbine Design Edited by: Wei Tong Kollmorgen Corp., USA Edited by: Wei Tong, Kollmorgen Corp., USA Published by WIT Press Ashurst Lodge, Ashurst, Southampton, SO40 7AA, UK Tel: 44 (0) 238 029 3223; Fax: 44 (0) 238 029 2853 E-Mail: witpress@witpress.com http://www.witpress.com For USA, Canada and Mexico WIT Press 25 Bridge Street, Billerica, MA 01821, USA Tel: 978 667 5841; Fax: 978 667 7582 E-Mail: infousa@witpress.com http://www.witpress.com British Library Cataloguing-in-Publication Data A Catalogue record for this book is available from the British Library ISBN: 978-1-84564-205-1 Library of Congress Catalog Card Number: 2009943185 The texts of the papers in this volume were set individually by the authors or under their supervision No responsibility is assumed by the Publisher, the Editors and Authors for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein The Publisher does not necessarily endorse the ideas held, or views expressed by the Editors or Authors of the material contained in its publications © WIT Press 2010 Printed in Great Britain by MPG Books Group, Bodmin and King’s Lynn 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, or otherwise, without the prior written permission of the Publisher Contents Preface List of Contributors xix xxiii PART I: BASICS IN WIND POWER GENERATION CHAPTER Fundamentals of wind energy Wei Tong Wind energy Wind generation 2.1 Uneven solar heating 2.2 Coriolis force 2.3 Local geography History of wind energy applications 3.1 Sailing 3.2 Wind in metal smelting processes 3.3 Windmills 3.4 Wind turbines 3.5 Kites Wind energy characteristics 4.1 Wind power 4.2 Wind characteristics Modern wind turbines 5.1 Wind turbine classification 5.2 Wind turbine configuration 5.3 Wind power parameters 5.4 Wind turbine controls Challenges in wind power generation 6.1 Environmental impacts 6.2 Wind turbine noise 6.3 Integration of wind power into grid 6.4 Thermal management of wind turbines 6.5 Wind energy storage 4 6 7 8 9 12 15 16 19 20 24 28 28 28 29 30 31 6.6 Wind turbine lifetime 6.7 Cost of electricity from wind power Trends in wind turbine developments and wind power generation 7.1 High-power, large-capacity wind turbine 7.2 Offshore wind turbine 7.3 Direct drive wind turbine 7.4 High efficient blade 7.5 Floating wind turbine 7.6 Wind turbine with contra-rotating rotors 7.7 Drivetrain 7.8 Integration of wind and other energy sources References 31 32 33 33 34 35 36 37 38 39 40 42 CHAPTER Wind resource and site assessment 49 Wiebke Langreder Initial site identification Wind speed measurements 2.1 Introduction 2.2 Instruments 2.3 Calibration 2.4 Mounting 2.5 Measurement period and averaging time Data analysis 3.1 Long-term correction 3.2 Weibull distribution Spatial extrapolation 4.1 Introduction 4.2 Vertical extrapolation 4.3 Flow models Siting and site suitability 5.1 General 5.2 Turbulence 5.3 Flow inclination 5.4 Vertical wind speed gradient Site classification 6.1 Introduction 6.2 Extreme winds Energy yield and losses 7.1 Single wind turbine 7.2 Wake and other losses 7.3 Uncertainty References 49 50 50 51 58 59 60 61 61 64 66 66 66 70 75 75 75 79 80 82 82 82 84 84 84 85 85 CHAPTER Aerodynamics and aeroelastics of wind turbines 89 Alois P Schaffarczyk Introduction Analytical theories 2.1 Blade element theories 2.2 Optimum blade shape Numerical CFD methods applied to wind turbine flow Experiments 4.1 Field rotor aerodynamics 4.2 Chinese-Swedish wind tunnel investigations 4.3 NREL unsteady aerodynamic experiments in the NASA AMES-wind tunnel 4.4 MEXICO Aeroelastics 5.1 Generalities 5.2 Tasks of aeroelasticity 5.3 Instructive example: the Baltic Thunder Impact on commercial systems 6.1 Small wind turbines 6.2 Main-stream wind turbines 6.3 Multi MW turbines Non-standard wind turbines 7.1 Vertical axis wind turbines 7.2 Diffuser systems Summary and outlook References 89 90 98 100 101 103 103 104 104 105 105 105 106 107 107 107 109 110 111 111 114 115 116 CHAPTER Structural dynamics of wind turbines 121 Spyros G Voutsinas Wind turbines from a structural stand point Formulation of the dynamic equations Beam theory and FEM approximations 3.1 Basic assumptions and equation derivation 3.2 Principle of virtual work and FE approximations Multi-component systems 4.1 Reformulation of the dynamic equations 4.2 Connection conditions 4.3 Implementation issues 4.4 Eigenvalue analysis and linear stability Aeroelastic coupling Rotor stability analysis More advanced modeling issues 7.1 Timoshenko beam model 7.2 Second order beam models 121 123 124 124 127 129 129 131 132 133 135 137 139 139 140 Structural analysis and engineering practice 8.1 Modes at stand still 8.2 Dynamic simulations 8.3 Stability assessment References 141 142 143 146 149 CHAPTER Wind turbine acoustics 153 Robert Z Szasz & Laszlo Fuchs What is noise? Are wind turbines really noisy? Definitions Wind turbine noise 4.1 Generation 4.2 Propagation 4.3 Immission 4.4 Wind turbine noise regulations Wind turbine noise measurements 5.1 On-site measurements 5.2 Wind-tunnel measurements Noise prediction 6.1 Category I models 6.2 Category II models 6.3 Category III models 6.4 Noise propagation models Noise reduction strategies Future perspective References 153 153 155 157 158 162 163 164 165 165 167 168 169 170 171 177 179 181 181 PART II: DESIGN OF MODERN WIND TURBINES CHAPTER Design and development of megawatt wind turbines 187 Lawrence D Willey Introduction 1.1 All new turbine design 1.2 Incremental improvements to existing turbine designs 1.3 The state of technology and the industry Motivation for developing megawatt-size WTs 2.1 Value analysis for wind 2.2 The systems view 2.3 Renewables, competitors and traditional fossil-based energy production 2.4 Critical to quality (CTQ) attributes 187 188 189 189 190 192 195 195 196 The product design process 3.1 Establishing the need 3.2 The business case 3.3 Tollgates 3.4 Structuring the team 3.5 Product requirements and product specification 3.6 Launching the product 3.7 Design definition: conceptual → preliminary → detailed 3.8 Continual cycles of re-focus; systems–components–systems MW WT design techniques 4.1 Requirements 4.2 Systems 4.3 Components 4.4 Mechanical 4.5 Electrical 4.6 Controls 4.7 Siting Special considerations in MW WT design 5.1 Continuously circling back to value engineering 5.2 Intellectual property (IP) 5.3 Permitting and perceptions 5.4 Codes and standards 5.5 Third party certification 5.6 Markets, finance structures and policy MW WT development techniques 6.1 Validation background 6.2 Product validation techniques Closure References 196 197 197 197 199 199 200 200 205 206 206 208 215 219 236 240 244 247 247 249 249 250 250 250 250 251 251 252 253 CHAPTER Design and development of small wind turbines 257 Lawrence Staudt Small wind technology 1.1 Small wind system configurations 1.2 Small wind turbine rotor design 1.3 System design 1.4 Tower design Future developments Conclusions References 257 260 262 267 273 274 275 276 .for scientists by scientists Tribology and Design Edited by: M HADFIEL, Bournemouth University, UK, C.A BREBBIA, Wessex Institute of Technology, UK and J SEABRA, University of Porto, Portugal Tribology and Design 2010 is the 3rd International Conference in a series that originated with two meetings held at Bournemouth University, UK in 2005 and 2007 The Tribology and Design Conference explores the role of technology and design in the broader sense It brings together colleagues from different disciplines interested in problems of surface interaction and design The applications covered range from geomechanics to nano problems and from sustainability issues to advanced materials It has never been so important for the designer to consider product and system durability in relation to reliability and sustainability issues The topics for discussion also cover studies of tribology in nature and how the resulting lessons can be applied by the designers Another important theme is the application of tribology in biomechanics, a field in which surface mechanics in general is of fundamental importance This book contains the papers presented at the Third International Conference, arranged into the following subject areas: Tribology in Space Applications; Reliability in Product Design; Nano-Tribology and Design; Tribology Under Extreme Conditions; Tribology in Geo-Mechanics; Energy Applications; Surface Measurements; Tribology in Biomechanics; LifeOriented Design; Tribology and Nature; Design Tools; Surface Engineering; Lubricant Design; Test Methods; Advanced Materials; Analytical Studies; Sustainability and Tribology; Product Reliability; Corrosion Problems WIT Transactions on Engineering Sciences, Vol 66 ISBN: 978-1-84564-440-6 eISBN: 978-1-84564-441-3 2010 304pp apx £115.00 .for scientists by scientists Structures Under Shock and Impact XI Edited by: N JONES, The University of Liverpool, UK , C.A BREBBIA, Wessex Institute of Technology, UK and Ü MANDER, University of Tartu, Estonia The shock and impact behaviour of structures presents challenges to researchers, not only because of its obvious time-dependent aspects, but also because of the difficulties in specifying the external dynamic loading characteristics and in obtaining the full dynamic properties of materials Thus it is important to recognise and fully utilise the contributions and understanding emerging from the theoretical, numerical and experimental studies, as well as investigations into material properties under dynamic loading conditions Of interest to engineers from civil, military, nuclear, offshore, aeronautical, transportation and other backgrounds, the topics covered include: Impact and Blast Loading Characteristics; Protection of Structures from Blast Loads; Energy Absorbing Issues; Structural Crashworthiness; Hazard Mitigation and Assessment; Behaviour of Steel Structures; Behaviour of Structural Concrete; Material Response to High Rate Loading; Seismic Engineering Applications; Interaction Between Computational and Experimental Results; Innovative Materials and Material Systems; Fluid Structure Interaction WIT Transactions on The Built Environment, Vol 113 ISBN: 978-1-84564-466-6 eISBN: 978-1-84564-467-3 Forthcoming apx400pp apx£152.00 Find us at http://www.witpress.com This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank This page intentionally left blank ... Trends in wind turbine developments and wind power generation 7.1 High -power, large-capacity wind turbine 7.2 Offshore wind turbine 7.3 Direct drive wind turbine 7.4... 4.1 Wind power 4.2 Wind characteristics Modern wind turbines 5.1 Wind turbine classification 5.2 Wind turbine configuration 5.3 Wind power parameters... almost all of earth’s energy needs 4 Wind Power Generation and Wind Turbine Design Wind energy represents a mainstream energy source of new power generation and an important player in the world's