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Note that according to [16], the first term of (D.5) reads A1 <strong>sin</strong>(�) 2 . This is an incorrect reproduction of the Viterna and Corrigan theory and it has therefore been corrected. The airfoil data of figure D.1 is valid for a Reynolds number Re of 3 × 10 6 and for airfoils with so-called NACA standard roughness. The Reynolds number for an airfoil is given by The length of the chord c and the relative wind speed W varies throughout the blade and there will thus be a variance of the Reynolds number, rendering the usage of airfoil data for a specific Reynolds number an approximation. The Reynolds number at the blade tip ranges from 3 × 10 5 to 7 × 10 5 at a wind speed of 4 m/s and 14 m/s, respectively. The significance of the deviance between the actual Reynolds numbers on the blade and AIRFOIL the Reynolds number of the airfoil data may be assessed from figure D.2, which shows the lift and drag coefficients for a NACA 4412 profile at various Reynolds numbers. Figure D.2: NACA 4412 lift and drag coefficients for various Reynolds numbers [48] (D.8) Figure D.2 reveals an invariance of the lift coefficient Cl as a function of Re. It further shows that the change in drag coefficient Cd is only 10% in the Re-range of 5 × 10 5 to 5 × 10 6 . For these reasons the usage of airfoil data that is valid for Re = 3 × 10 6 is considered to be an acceptable approximation. U<strong>sin</strong>g data that is based on the NACA standard roughness ensures conservative values of lift and drag, as it is generally considerably more severe than the roughness generally obtainable on real blade surfaces [49]. Wind tunnel tests of the airfoil performance are not carried out in the present project, as the surface properties of test specimens will vary from those of a real blade. Testing should be performed when a prototype is build, ref. chapter 12. c W Re = � 145
LIST OF ATTACHMENTSAIRFOIL Complete calculations of the airfoil data can be found in the rotor design tool. Printouts are provided as att. 8. 146 D.1 Profile shape The NACA 4412 airfoil profile shape in each blade element is described as a function of the local chord length via geometrical data found in [50]. The rotor design tool uses the data to describe the airfoil shape with 102 Cartesian coordinates per element, as shown on figure D.3. Profile height [m] 0.03 0.02 0.01 0.00 -0.01 -0.02 0.00 0.05 0.10 0.15 0.20 0.25 Figure D.3: NACA 4412 airfoil shape in all elements of the rotor design tool The coordinate data, which is provided as att. 9, is further used as shape coordinates in the 3D CAD model of the blades. Chord length [m]
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WIND TURBINE DESIGN
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ABSTRACT At the request of the Engi
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CONTENTS 1 Introduction ...........
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E Structural analysis of blades ...
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INTRODUCTION members. Today EWB-DK
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INTRODUCTION Figure 1.2: Left pictu
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INTRODUCTION 6
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PROBLEM STATEMENT reconfigured with
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PROBLEM STATEMENT 10
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METHODOLOGY Figure 3.1: Flow chart
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METHODOLOGY 14 3.1 Calculation meth
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CONCEPTUALISATION the kinetic wind
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CONCEPTUALISATION Figure 4.3: (a) D
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CONCEPTUALISATION issues due to tur
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CONCEPTUALISATION 22 Figure 4.8: Ty
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CONCEPTUALISATION � Darrieus 24 F
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CONCEPTUALISATION 26 Figure 4.13: G
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CONCEPTUALISATION Figure 4.14: Powe
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CONCEPTUALISATION 30 ID Requirement
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CONCEPTUALISATION most suitable sol
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CONCEPTUALISATION The embodiment de
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DESIGN PRESENTATION The main dimens
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DESIGN PRESENTATION The design prop
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DESIGN PRESENTATION The background
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ROTOR 42 6.1 Number of blades Moder
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ROTOR 44 Figure 6.4: Blade design s
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ROTOR Table 6.3 provides a material
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ROTOR Figure 6.7 displays the lift
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ROTOR Figure 6.9: Rotor power outpu
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ROTOR 6.2.3 Manufacturing During th
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ROTOR 54 The three sides of the tem
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ROTOR When the carving process is f
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ROTOR 58 Figure 6.17: Blade attachm
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ROTOR 60 Figure 6.19: Rotor power o
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ROTOR 62 Figure 6.22: Efficiency
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ROTOR sidering the output from the
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ROTOR 66
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GENERATOR AND ELECTRICAL SYSTEM 68
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GENERATOR AND ELECTRICAL SYSTEM The
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GENERATOR AND ELECTRICAL SYSTEM Fig
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GENERATOR AND ELECTRICAL SYSTEM 74
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YAW AND FURLING For an upwind wind
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YAW AND FURLING (16), which are bol
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YAW AND FURLING 80 8.2 Furling syst
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YAW AND FURLING 82 8.3 Summary The
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TOWER Concrete tower 84 Figure 9.1:
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TOWER 86 Figure 9.4: Turbulent air
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TOWER Figure 9.7 shows the tower ba
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TOWER models [41, p. 111]. Under ce
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ALTERNATIVE BLADE DESIGN 92 10.1 Ai
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Page 103 and 104: DESIGN EVALUATION 96 6 W Low-cost m
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Page 107 and 108: FURTHER DEVELOPMENT � Foundation
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Page 111 and 112: CONCLUSION proposal is highly flexi
Page 113 and 114: NOMENCLATURE Abbreviation Descripti
Page 115 and 116: NOMENCLATURE Lgs Distance between u
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Page 119 and 120: BIBLIOGRAPHY [14] Magenn Power Inc.
Page 121 and 122: BIBLIOGRAPHY [53] H. J. Larsen, H.
Page 123 and 124: LIST OF ATTACHMENTSBASIS FOR CALCUL
Page 139 and 140: LIST OF ATTACHMENTSROTOR THEORY Thi
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Page 143 and 144: LIST OF ATTACHMENTSROTOR THEORY Cho
Page 145 and 146: LIST OF ATTACHMENTSROTOR THEORY 138
Page 147 and 148: LIST OF ATTACHMENTSROTOR DESIGN TOO
Page 149 and 150: LIST OF ATTACHMENTSROTOR DESIGN TOO
Page 151: LIST OF ATTACHMENTSAIRFOIL With the
Page 155 and 156: LIST OF ATTACHMENTSSTRUCTURAL ANALY
Page 191 and 192: LIST OF ATTACHMENTSBLADE ATTACHMENT
Page 197 and 198: LIST OF ATTACHMENTSSTRUCTURAL VERIF
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LIST OF ATTACHMENTSTOWER ANALYSIS T
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LIST OF ATTACHMENTSFURLING AND YAW
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LIST OF ATTACHMENTSALTERNATIVE AIRF
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LIST OF ATTACHMENTSCOMPLIANCE WITH
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