11 September 2008 D. Schwab and A.P. Schaffarczyk (APS) CEwind and UAS (FH) Kiel

Transkript

1 Science Meets Practice Innovations for Wind Energy HUSUM WindEnergy 11 September 2008 D. Schwab and A.P. Schaffarczyk (APS) CEwind and UAS (FH) Kiel

2 Measure Yaw Misalignment: New Methods and Models The Influence of Yawing Error on Performance of Wind Turbines

3 Contents Introduction CEwind Actuator Disk Models Measurements in Wind Tunnels Summary and Outlook

4 CEwind in a Nutshell 1. Period: Period under Consideration : Eingetragene Forschungs-Genossenschaft (e.g.) Own legal form: Cooperative Society Budget about 1M /a Network of : University Kiel (Tech. Fak., FTZ Westküste), University Flensburg (Prof. Hohmeier, IPCC) all Universities of Appl. Sciences Nordakademie Elmshorn

5 Special Projects Mechanical Engineering 1. Period : 2. Period: 1. Offshore Windturbine Foundation Structural Design of Rotorblades (Prof. Dannenberg, FH Kiel) 2. Aerodynamics and Aeroelastics of Large Rotor-Blades (Prof. Schaffarczyk, FH Kiel) 3. Condition Monitoring (Prof. Krapoth / Prof. Reimers FH Flensburg) Aerodynamic Glove CM of Blades including Power Electronics (Prof. Fuchs, CAU)

6 Special Project: MSc Wind Engineering Starting NOW! Applications Welcome! Master-Thesis S3 Grid Integration And High Generator and Power Electr.. Control Systems and Automation Basics Environment Add. Courses like Add. Courses like S2 Noise & Vibration Structural Strength & Materials Aerodynamics Sustainable Energy Systems Shaping Sustainable Energy Systems Add. Courses like S1 1 CP Add. Courses like Advanced Windturbine Systems Off-Shore Mathematics Measurment and Certification External Costs of Energy Trading Energy 1 Modul = 5cp: Lectures Exercises Laboratory Course Power Train Components Emphasis Environment Business Economics Project Work

7 Offshore Measurement platform FINO 3 Construction in nm west of the island of Sylt measurements of wind and rainfall, tide and drift, interaction between foundation and ground, lightning parameters, Subproject: Measurement and analysis of high- frequency (<10 khz) turbulence parts in the offshore wind for optimization of aerodynamic profiles

8 Actuator Disk Modeling of Yawed flow (1) Yawed Flow: Wind NOT in Direction of Rotational Axis Main Questions: Which Loss in Power? What Changes in Loads? Disc = British Disk = American

9 AD Modeling of Yawed flow (2) Actuator Disk (Rankine, Froude, 19th Century) Rotor is modeled as infinitely thin solid disk no effects of finite number of blades included (Semi)-Analytical Method applicable: Solution of Axis-symmetric, inviscid Euler-Equations Mathematical formulation in terms of velocity potentials

10 AD Modeling of Yawed flow (3) Problem for applying momentum theory -> Axis Symmetry is lost! Improved AD Models (From Helicopter Applications): (1) Axial Momentum only (2) Glauert Momentum (1926) (3) Vortex Methods (Coleman et. al. 1945)

11 Results (1) Simplest Model (1) Circumferential Averaged Axial induction as function of yaw angle : Gives: cp(-max) of approx. 1 % loss for 5 deg yaw-angle *** Most used engineering formula *** (not talking about exponent 3 )

12 Results(2) Losses rather model-dependent if yaw angle becomes large: 10 Source: Wind Energy Handbook

13 New AD Model(1) Conway (2001) gives a non-linear semi-analytic AD theory for non-axi symmetric flow Special load distribution in form of polynomial Enthalpie-Streamfunction functions necessary This triggered a CFD test of the method Hub Tip

14 New AD-Method (2) Sketch of axial Flow-Field, 10 deg yaw, TSR = 6 Commercial CFD-Code FLUENT improved by User- Subroutines

15 New AD-Model(4) Total axial velocity

16 New AD-Method (3) Some difference can be seen Conway = light green

17 Yawed Flow Loads (1) Mikkelsen (2004), 30 deg yaw Flapwise root bending moment Dynamic stall important

18 NASA AMES (World Largest) Wind-Tunnel Power: 6 x 13.6 MW

19 2 bladed 10 m diameter Test-Turbine

20 Yawed Flow Loads(2) NREL-NASA-AMES Experiment (2000) Circumferential Normal Force against BEM modeling --Solid Line (meas.) Strong variation of Design-Codes -- thin lines (theory)

21 (European) Mexico Experiment ( ) 3-bladed wind-turbine in Largest European wind-tunnel Diameter 4.5 m

22 IEA-Task for Evaluation of results I(nternational) E(nergy) A(gency) Special Task starts today (Therefore APS is absent) MEXNEX(T): Analysis of Wind Tunnel Measurements and improvement of aerodynamic models Also Yawed Flow was extensively measured

23 Summary Yawed Flow is unsteady 3D therefore modelling is full of simplification ongoing research(nrel/nasa-ames, MEXICO) important for turbine control optimization -> following presentation of ixist

24 The End many thanks for your attention!