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Friction forces and moments FURLING AND YAW ANALYSIS (I.13) The friction force in the bearings is calculated from the sum of the reaction force in the two bearings, which is: Using a friction coefficient µs of 0.2, the friction force becomes: This is recalculated into a frictional resistance moment: A total frictional resistance moment is calculated by further adding the required starting (I.14) (I.15) (I.16) torque for the thrust bearing Mst, which is 28.8 Nmm. The calculation, which is documented in att. 3, uses the following input: � Bearing load: 997 N � The number of rotations per minute: 1 rpm � Friction coefficient in full-film condition: 0.1 µEHL, which corresponds to grease used as lubrication in the bearing. Yawing moment The aerodynamic lift and drag forces on the tail vane will tend to align the rotor with the wind, whereas the thrust force on the rotor and the above calculated frictional resistance (I.17) moment will oppose the tendency. Using principles of equilibrium it is possible to calculate a steady state yaw offset. The lift force is perpendicular to the wind direction and the drag is parallel to the wind direction, which is shown on the free body diagram of the tail vane and the rotor on figure I.3. RB Rx.B 2 Ry.B 2 � � � 354 N Rtot � RA � RB � 721N Ffr � Rtot s � 144N Mfr � Db Ffr 2 � 6.70Nm Mfr.tot � Mst � Mfr � 6.73Nm 205
LIST OF ATTACHMENTSFURLING AND YAW ANALYSIS 206 Figure I.3: Free Body Diagram of the tail vane and rotor Both the lift and drag forces may be divided into components along the x-axis and the y- axis. It is seen that both the lift and drag forces contribute to a moment (CW) about the yaw axis, which is: Where Av is the area of the tail vane equal to 1.04 m 2 and: Aerodynamically the tail vane is considered a thin flat plate. The drag coefficient is there- (I.18) (I.19) (I.20) (I.21) (I.22) fore approximated as Cd = 1.28 sin(�) and the lift coefficient as Cl = 2��, see [63] and [64, p. 557], respectively. Mv � FxLv.y � FyLv.x Fx � Fdcos ( �) � Flsin( �) Fy � Fdsin( �) � Flcos ( �) Mv � Fx Lv.x � Fy Lv.y Fl � 1 2 V2 Av Cl 1 Fd 2 V2 � Av Cd The moment from the rotor thrust force about the yaw axis is calculated as (positive CCW):
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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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ALTERNATIVE BLADE DESIGN 94 10.3 Su
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DESIGN EVALUATION 96 6 W Low-cost m
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DESIGN EVALUATION Weaknesses 1) The
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FURTHER DEVELOPMENT � Foundation
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FURTHER DEVELOPMENT 102
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CONCLUSION proposal is highly flexi
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NOMENCLATURE Abbreviation Descripti
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NOMENCLATURE Lgs Distance between u
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NOMENCLATURE 110
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BIBLIOGRAPHY [14] Magenn Power Inc.
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BIBLIOGRAPHY [53] H. J. Larsen, H.
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LIST OF ATTACHMENTSBASIS FOR CALCUL
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LIST OF ATTACHMENTSROTOR THEORY Thi
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LIST OF ATTACHMENTSROTOR THEORY 134
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LIST OF ATTACHMENTSROTOR THEORY Cho
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LIST OF ATTACHMENTSROTOR THEORY 138
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LIST OF ATTACHMENTSROTOR DESIGN TOO
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LIST OF ATTACHMENTSROTOR DESIGN TOO
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LIST OF ATTACHMENTSAIRFOIL With the
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LIST OF ATTACHMENTSAIRFOIL Complete
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LIST OF ATTACHMENTSSTRUCTURAL ANALY
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Page 161 and 162: LIST OF ATTACHMENTSSTRUCTURAL ANALY
Page 191 and 192: LIST OF ATTACHMENTSBLADE ATTACHMENT
Page 197 and 198: LIST OF ATTACHMENTSSTRUCTURAL VERIF
Page 203 and 204: LIST OF ATTACHMENTSTOWER ANALYSIS T
Page 209 and 210: LIST OF ATTACHMENTSFURLING AND YAW
Page 211: LIST OF ATTACHMENTSFURLING AND YAW
Page 221 and 222: LIST OF ATTACHMENTSALTERNATIVE AIRF
Page 231: LIST OF ATTACHMENTSCOMPLIANCE WITH
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