On the use of rotor equivalent wind speed to improve CFD wind resource mapping. Yavor V. Hristov, PhD Plant Performance and Modeling Vestas TSS

Transcription

1 On the use of rotor equivalent wind speed to improve CFD wind resource mapping Yavor V. Hristov, PhD Plant Performance and Modeling Vestas TSS

2 Firestorm- Number 53 on Top500 list from June processors on 1222 hosts each with 2 Intel X5670 (hex core) processors and 24 GB memory 24 GPU s with 192 GB RAM and M2070Q graphic card 4xQDR (40Gbit) Infiniband network 2.6 PetaB fast parallel storage 150+ TFLOP/S Energy consumption -0.5 MW, cooling only uses 10% of the power

3 VestasFOAM- CFD process based on OpenFOAM Vestas Site automated Check provides reports industry (turbulence standard wasp structured VestasFOAM map contour hyperbolic customized file mesh extrusion from intensity, inflow angles, wind shear) in simplefoam Pointwise with Glyph2 macro wasp.map Vestas -> plot3d Site conversion Check input and cut for Load to turbine utility standard buffer distance used ABL to generate steady profiles calculations hanging node architecture Terrain edge k-epsilon smoothing turbulence for even model inlets with wind flow parameters at hub height for and mesh msh modified extrusion format constants resource considerations map OpenFOAM calculationsformat unstructured customized inlet/outlet meshing also and available terrain boundary conditions fluent3dmeshtofoam VestasFOAM

4 Level 2- VestasFOAM special cases- forest, extremely complex terrain Echo Echo First echo = Vegetation Last echo = Ground

5 Level 3- Unsteady (Hybrid RANS/LES) simulations with VestasFOAM

6 Level 3- Unsteady (Hybrid RANS/LES) simulations with VestasFOAM

7 Level 4 Mesoscale- CFD coupling Atmospheric boundary layer stability considered CustomizedbuoyantBoussinesqPimpleFoam surface heat flux buoyancy Boussinesq approximated DES turbulence model Height (m) Height (m) temperature and velocity profiles obtained from WRF Horizontal Velocity (m/s) Temperature (K)

8 Level 5 Mesoscale- CFD - ALM coupled model When mesoscale data indicates predominant non-neutral conditions, mesoscale profiles are dynamically coupled with CFD (LES) in order to link real-wind with the microscale domain. In addition turbine wake interactions are investigated using actuator line modeling.

9 CFD wind resource mapping validation based on 50 projects in operation Run 36 sectors CFD simulation Multiple masts Long term corrected to Vestas 13 year mesoscale WRF model data Extrapolation of mast data to hub height according to CFD predicted wind shear Scaling CFD wind velocity field to match measurements at mast positions Inverse distance interpolation together with directional wind distribution frequencies for each met mast is used to calculate the Weibull parameters with 25 m resolution Creating RSF file Annual production based on SCADA data extracted and compared to CFD predicted AEP

10 Vestas site 22 V90-3MW with HH 80 m Mast 1 Mast 2

11 Mast 2 60 m adjustment of wind speed Reference correction function for Mid-West USA Turbulence intensity measured at Mast 2 Anna Marsh, 2013 Resource Assessment Methods Incorporating Rotor Equivalent Wind Speed, Density and Turbulence on a Time Step Basis

12 Mast 2 60 m adjustment of wind speed deg Correc tion TI Wind Shear Correction factors, TI measured and CFD simulated Wind Shear per sector

13 Validation of CFD predicted AEP WTG AEP CFD AEP CFD AEP_REWS Error CFD Error CFD_REWS improvement % 16.22% 1.68% % 14.95% 1.85% % 14.76% 1.98% % 12.89% 1.81% % 12.76% 2.13% % 12.55% 2.06% % 14.90% 2.42% % 14.38% 2.54% % 12.96% 2.35% % 12.94% 2.21% % 11.75% 2.33% % 9.86% 2.21% % 11.15% 2.27% % 10.82% 2.24% % 8.31% 1.97% % 9.99% 2.25% % 12.48% 2.56% % 9.60% 2.51% % 9.36% 2.43% % 10.77% 2.44% % 7.73% 2.32% % 8.96% 2.44% total % 11.76% 2.23%

14 Discussion 1. Can rotor equivalent wind speed relation to TI at the assessed site be used for other sites? Under what conditions? 2. What is the microscale/mesoscale phenomena behind strong correlation between wind shear and TI? Stable stratification leading to less mixing hence low TI and high wind shear typical for Mid-West US? 3. What is the uncertainty in deriving the rotor equivalent wind speed through integrating wind profiles based on mesoscale profiles across rotor plane?

15 Thank you for your attention Copyright Notice The documents are created by Vestas Wind Systems A/S and contain copyrighted material, trademarks, and other proprietary information. All rights reserved. No part of the documents may be reproduced or copied in any form or by any means - such as graphic, electronic, or mechanical, including photocopying, taping, or information storage and retrieval systems without the prior written permission of Vestas Wind Systems A/S. The use of these documents by you, or anyone else authorized by you, is prohibited unless specifically permitted by Vestas Wind Systems A/S. You may not alter or remove any trademark, copyright or other notice from the documents. The documents are provided as is and Vestas Wind Systems A/S shall not have any responsibility or liability whatsoever for the results of use of the documents by you.