APPLICATION OF RESEARCH RESULTS AT LM WIND POWER

Transcription

1 APPLICATION OF RESEARCH RESULTS AT LM WIND POWER Herning / March 27 / 2014 By Jesper Madsen Chief Engineer Aerodynamics and Acoustics

2 AGENDA 1. EUDP Projects 1. DANAERO MW 2. Optimization of vortex generators on wind turbine blades 3. Design of next generation wind turbine rotors (NextRotor) 4. Overcoming critical design challenges of wind turbines 2. Conclusions 3. Suggestions for further research 2

3 EUDP projects Energiteknologiske Udviklings- og Demonstrationsprojekter DANAERO MW projects (completed): 1. Seven airfoils tested in three different wind tunnels 2. Inflow measurements on a 3.6 MW Siemens wind turbine (no LM participation) 3. A heavily instrumented 2MW NM80 wind turbine, where blade surface pressures, boundary layer noise at the tip, strain gauges, accelerometers, wind speed wind direction, power etc. were sampled Optimization of vortex generators on wind turbine blades (completed): 1. Optimal use of vortex generators that are presently used on most LM wind turbine blades Design of next generation wind turbine rotors, NextRotor (on-going): 1. Development of reliable integrated rotor design tools and to design efficient, low noise rotors that are demanded in the future wind energy market for onshore application Overcoming critical design challenges of wind turbines (on-going): 1. Design and validation of new thick airfoils 2. Identification of 2D/3D thick airfoil data 3. Identification of the standstill problem using aeroelastic 3D computational fluid dynamics 3

4 DANAERO MW Projects Tjæreborg field experiment on the 2.3 MW NM80 turbine with LM 38.8 P blades: Instrumentation on the LM38.8 blade:: Strain gauges Pressure tabs at four sections Five-hole Pitot tubes at four sections Microphones for high frequency surface pressure measurements at one section High frequency measurements of wind speed and direction from nearby met mast Wind tunnel tests in the LM Wind Power tunnel: Measurements on four airfoils with the same shape as the instrumented sections on the LM38.8 blade of the NM80 turbine 4

5 DANAERO MW Projects The DANAERO MW test that was carried out in The DANAERO MW II project was carried out in Unique data and project: First mega Watt wind turbine test in the world with Detailed pressure measurements equipment and surface mounted microphones operating in atmospheric conditions Clarifying the influence from the atmospheric inflow on the boundary layer on the airfoil and thereby the aerodynamic characteristics, which again determines the wind turbine characteristics Partners consisted of DTU Wind Energy Vestas Siemens LM Wind Power Results, e.g.: Increased the credibility of existing design codes Revealed mechanisms concerning noise generation Validation of CFD codes 5

6 3D CFD Calculations of Rotor Flow EllipSys3D Blade tip details WS = 8m/s Anemometer location 6

7 Validation of rotor CFD with DANAERO field measurements Spanwise tangential force Spanwise normal force Simulations are carried out with the EllipSys3D CFD code using k-ω SST & γ-re θ turbulence and transition models Near the blade root, for low Tu case, transitional simulation predicts higher forces compared to fully turbulent simulation 7

8 Validation of rotor CFD with DANAERO field measurements Pressure coefficient at R=13 m Conclusions: The results show good agreements Gives confidence for application of CFD for design of new blades 8

9 Optimization of vortex generators on wind turbine blades Vortex Generators, VGs: VGs are small fins placed on the surface of the wind turbine blades VGs improves the aerodynamic efficiency, which makes it possible to produce even slimmer blades Results for LM Wind Power: Comprehensive studies in the LM wind tunnel The project made it possible to optimize the placing of conventional VGs Optimized placing is now used on commercialized LM blades Furthermore there has been produced an even better VG geometry, which effect is verified by tests in the wind tunnel 9

10 Wind Tunnel Measurements of VGs Measured polars Vortex generator flow visualization Clean surface Vortex generators Lift increases with decreasing chord wise position Different VG chord wise positions Flow is separating without VGs VGs maintain attached flow 10

11 Design of next generation wind turbine rotors (NextRotor) Outcomes of the (on-going) project: Reliable tools for designing and validating high efficient, low cost and low noise rotors The tools are used for design of commercialized low noise wind turbine blades The aerodynamic and acoustic performance of the airfoils are validated experimentally By applying the developed tools, a noise reduction of 2 db(a) without reducing annual energy yield for a 2 MW wind turbine, is demonstrated 11

12 Airfoil aeroacoustic prediction Based on semi-empiric methods Methods have been widely used in (external) research and published papers Optimized code and validated against measured data Noise sources individually modeled

13 From airfoil to rotor noise

14 Comprehensive rotor acoustic results

15 L_eqA [db(a)] L_eqA [db(a)] Validation against acoustic field data Case #1 Case # Wind speed [m/s] Wind speed [m/s] Simulated Measured Simulated Measured 15

16 Overcoming critical design challenges of wind turbines Testing of thick airfoils in LM Wind Power Wind Tunnel 360 wind tunnel testing 16

17 LM Wind Power Wind Tunnel Airline layout: Top view: 37 m x 14 m Max wind speed: 105 m/s Reynolds number: 6 millions Turbulence intensity: 0.1% 17

18 Side wall effects Blower system results It can be seen that the blower system has a significant impact on the flow. A kink in the lift curve, here at AOA 4 is apparent when the blower is off. The flow is then three-dimensional. Side wall flow energized by blowers Thick airfoil Lift polars The usage of the blower system eliminates the discontinuity. No Blowing With Blowing Separated 3D Vortex flow Attached flow Flow remains mostly attached 18

19 Wind Tunnel CFD Model LM Wind Tunnel Geometry 2D WTCFD Process Automated process from grid generation to post processing Existing Wind Tunnel wall correction method implemented into process 3D WTCFD Process Automated Meshing process Outflow Wall Inflow Outflow Wall Inflow 19

20 Wind Tunnel CFD Results Vortex shedding from an airfoil at AOA 90 in wind tunnel test section 20

21 Conclusions LM Wind Power research projects and results are applied for: Continues development and validation of design tools Development of test and validation methods Overall, the application of research results helps to ensure competitive aerodynamic and acoustic performance of LM blades 21

22 Suggestions for future work in aerodynamic and acoustic research Aerodynamics and aeroelasticity: Longer flexible slender blades Up-scaling from current design methods High tip speeds (compressibility) Advanced aerodynamic sensors and controls Multi-mega-Watt turbine field testing Aeroacoustics: Further development and validation of prediction methods Understanding of low-frequency noise and amplitude modulation behavior and effects Bridging gap between small scale wind tunnel experiments and full scale rotor acoustics 22

23 Thank you for your time Contact details: Head quarters: Jesper Madsen LM Wind Power Group Chief Engineer Jupitervej 6 Aerodynamics and Acoustics 6000 Kolding Denmark Tel Tel Mob Fax E jema@lmwindpower.com E info@lmwindpower.com W lmwindpower.com Note: The contents of this presentation are confidential and may not be copied, distributed, published or reproduced in whole or in part, or disclosed or distributed by recipients to any other person. 23