WIND TURBINE ACOUSTICS - a sneak preview on research topics- Dr. Andree Altmikus ENERCON Research & Development

Transcription

1 WIND TURBINE ACOUSTICS - a sneak preview on research topics- Dr. Andree Altmikus ENERCON Research & Development 1

2 INTRODUCTION 1 AERO-ACOUSTICS 2 VIBRO-ACOUSTICS eddys in: STRUCTURAL VIBRATION ATMOSPHERIC BOUNDARY LAYER AIRFOIL S BOUNDARY LAYER BROAD-BAND NOISE TONAL NOISE ISO L R = L WA + K + Dc (Adiv + Aatm + Agr + Abar + Amisc) - Cmet 3 REGULATIONS 2

3 3 AERO-ACOUSTICS

4 NOISE SCALING by TIP SPEED EMPIRICAL NOISE MODEL BY HAGG 50 log 10log 9.1[dB(A)] 4

5 INFLOW NOISE TIP VORTEX LEADING EDGE SEPARATION TRAILING EDGE FLOW TURBULENCE IN ONCOMING FLOW U SURFACE BOUNDARY LAYER TRANSITION LAMINAR / TURBULENT WAKE L p [db] IT log f [Hz] 5

6 SEPARATNION NOISE TIP VORTEX LEADING EDGE SEPARATION TRAILING EDGE FLOW TURBULENCE IN ONCOMING FLOW U SURFACE BOUNDARY LAYER TRANSITION LAMINAR / TURBULENT WAKE BOUNDARY LAYER SEPARATION L p [db] IT LARGE-SCALE SEPARATION (DEEP STALL) SEP log f [Hz] SEPARATION-STALL NOISE 6

7 TURBULENT BL NOISE TIP VORTEX TURBULENT BOUNDARY LAYER TRAILING EDGE WAKE LEADING EDGE SEPARATION TURBULENCE IN ONCOMING FLOW TRAILING EDGE FLOW AIRFOIL TURBULENT- BOUNDARY-LAYER TRAILING EDGE NOISE U SURFACE BOUNDARY LAYER TRANSITION LAMINAR / TURBULENT WAKE L p [db] IT TBL-TE SEP DIRECTIVITY FUNCTION FOR THE NOISE log f [Hz] 7

8 SIMULATION vs. MEASUREMENT Excellent agreement between simulation and measurement 8

9 POWER INCREASED NOISE OPERATION MODES OM CONCEPT BM2 BM1 BM0 Power increase comes from high torque at low rotational speed n eff C L T At the same time noise decreases according to HAGG s model Same SPL same SPL n L AW 5 Power increase by increased magnetic excitation at lower rotational speeds 9

10 EFFECTS on POWER and NOISE Significant increase of nominal power at same sound power level (SPL) New modes will maximize annual energy production No increase in noise emissions, slight reduction at partial load New modes will be offered in steps of 1dB for high SPL, 2dB steps for lower SPLs 10

11 FEASIBILITY of OMs PROVEN BY FIRST MEASUREMENTS (E-115) OM Concept OM Measurement BM2 BM1 BM0 Power increase by only moderate pitching at same tip speed 11

12 FIRST MEASURMENT RESULTS on POWER New sound reduced modes have increased maximum power Further experimental consolidation is an 12

13 INCREASED POWER PERFOMANCE for ACOUSTIC OMs ENERCON: Current modes ENERCON: Modes available 2017 OM 0, I, II Steps: 1dB Steps: 2dB Nordex N117 (3.0MW) MODES OF COMPETITORS: Sound power levels in db(a) Senvion MM114 (3.2MW) Vestas V126 (3.45MW) Siemens SWT113 (3.2MW) Sound power level [db(a)] ,0 MODES WITH APPROX. SPL 101.5DB(A) Nominal Mode with approx dB 106,0 105,5 104,2 101,5 101,5 101,0 101,5 AEP delta 0,00% -5,00% -10,00% -15,00% -20,00% RESULTING AEP LOSS (compared to nominal mode at 6m/s mean wind speed) 13

14 14 VIBRO-ACOUSTICS

15 VIBROACOUSTICS ACCELERATION MEASUREMENTS EXCITATION SIMULATIONS VALIDATION ACOUSTIC MEASUREMENTS EMISSION SIMULATIONS ENERCON develops innovative simulation methods to investigate vibro-accoustic transmission from the generator via surrounding components to the environment Field validation is performed with newest techniques according to the latest regulations. 15

16 EXCITATION SOURCE Simulations of the electromagnetic forces serve as input for the dynamic turbine model 16

17 MAIN EMITTING SURFACES from SIMULATION NACELLE BLADE-ROOT The dynamic turbine model reveals the main emitting surfaces of structure born sound 17

18 PROPAGATION of STRUCTURE BORN SOUND in AIR Structural sound spectrum is propagated through the air to emission point 18

19 VALIDATION of AIR BORN SOUND SIMULATION SPL [db] 5 db Drehzahl Simulation Validation Good agreement allows for meaningful delta evaluations of noise optimization measures 19

20 IDENTIFICATION AND ANALYSIS OF ACOUSTIC PHENOMENA a. subjective listening b. frequency spectrum from airborne sound measurements c. operational displacement shapes from structure-born sound measurements d. Sound source localization using acoustic camera BLADE ROOT G-ROTOR HUB 20

21 21 REGULATIONS

22 GERMAN WORKING GROUP FOR IMMISSIONS (LAI) NOISE CALCULATIONS FOR WEC SO FAR: ISO (1998), developed for noise sources up to 30 m and m distance ISO is also fixed in LAI Hinweise (2005) for national use in Germany = Bund/Länder-Arbeitsgemeinschaft für Immissionsschutz Working group of the Federal states on immissions GENERAL QUESTION: Is the current ISO-standard valid for WEC s? NO REQUIRES RESEARCH! Source: Hirsch, Dokumentation zur Schallausbreitung

23 NEW LAI-DRAFT 2017 DRAFT IS BASED ON A SINGLE MEASUREMENT CAMPAIGN BY 10 nights, flat terrain, 2 WEC results differed from ISO with increasing distance up to 4 db development of Interimsverfahren/interims method - abolition of ground attenuation (up to 4,8 db) admission to a new LAI-draft 2016/17 for all federal states for QUESTIONS: Is one campaign enough for national rule change? Is this campaign representative for other/all sites? NO REQUIRES RESEARCH! 23

24 LAI-DRAFT 2017: POTENTIAL IMPACTS ON FUTURE PLANNINGS APPLICATION OF LAI-INTERIMS-METHOD ON A SAMPLE PROJECT: Existing wind farm with 8 WEC, new planning 6 WEC with 3 MW each (hh 149m) Strong reduction of kw-exploitation on the planning area 24

25 CALCULATION of SPREAD ACCORDING to ALTERNATIVE & INTERIM METHOD TECHNOLOGY MAKES A DIFFERENCE - E-115 W/ AND W/O TES AS AN EXAMPLE All spectra were normalized to the sound power level of 105 db(a) at hub height of 149m WECs with low energy content in the lower frequency range (TES) lead to significant lower prognosis levels in the forecast calculation when interim method is applied 25

26 THE NEW LAI-DRAFT 2017 : ENERCON s ACTIVITIES ENERCON is working actively on new propagation model to match reality better than interim method TARGET: minimize planning restrictions ENERCON teamed-up with notable noise experts TARGET: establish a more realistic propagation model and anchor it in new DIN norm ENERCON has got in contact with all federal ministries of environment TARGET: place new LAI-advice on safer ground 26

27 27 CURRENT NOISE RESEARCH

28 FURTHER NOISE RELATED RESEARCH PROJECTS SchallPro: Validation of noise propagation models on various sites OAM: Measurement and evaluation procedures for other amplitude modulation noise TremAC: Noise and infra sound propagation with psycho-acoustic evaluation SeraFin: Separation noise detection and mitigation control by new sensor techniques UBEGA: Uncertainty evaluation of noise and power performance curves UBEGA TremAC Measurement for validation of propagation models SeraFin 28

29 CONCLUSIONS ENERCON uses high fidelity simulations for WEC development ENERCON strives for systematic validation data by sophisticated prototype measurements ENERCON supports customers regarding new regulations in order to reduce planning risks ENERCON provides sophisticated technical solutions for innovative products ENERCON GmbH Dreekamp 5 D Aurich Telefon: Fax: