Model tests of wind turbines in wind tunnels

Richard G.J. Flay

Abstrakt

This paper describes methods for testing model wind turbines in wind tunnels based on published data and the experience gained by the author through having tested many different wind turbines in wind tunnels at the University of Auckland. Wind tunnels can be used to determine the performance of small wind turbines at full scale, or larger wind turbines at reduced scale. Such experiments need to be done with care as one needs to be aware of issues regarding blockage, the effect of Reynolds number, and being able to control the speed of the turbine so that is power coefficient can be obtained over a suitable range of tip speed ratios. With rotating machinery, it is also important to have a regard to safety, so the models have to be made with care and a stress analysis carried out to ensure that the material properties are not exceeded during the testing. It is found that wind tunnel testing is a useful way of determining experimentally the performance of wind turbines in order to predict the power output, and for obtaining data to validate theoretical or numerical model predictions.

Słowa kluczowe: wind engineering, wind energy, wind tunnel test, blade aerodynamics, renewable energy, blockage correction
References

[1] B locken B., Carmeliet J., Stathopoulos T., CFD evaluation of wind speed conditions in passages between parallel buildings - effect of wall-function roughness modifications for the atmospheric boundary layer flow. Journal of Wind Engineering and Industrial Aerodynamics, Vol. 95(9-11), 2007, 941-962.

[2] Builtjes P.J.H., Milborrow D.J., Modelling of wind turbine arrays. Proc. 3rd International Symposium Wind Energy Systems, Denmark, Copenhagen 1980.

[3] Barlow J.B., Rae W.J., Pope A., Low speed wind tunnel testing, Wiley-Interscience, John Wiley and Sons, USA 1999.

[4] Bottasso C.L., Campagnolo F., Petrovi V., Wind tunnel testing of scaled wind turbine models: Beyond aerodynamics, Journal of Wind Engineering and Industrial Aerodynamics, Vol. 127, 2014, 11-28.

[5] C hasteau V.A.L., Operational experience with a 5 m Darrieus wind turbine, Proc. 6th Australasian Hydraulics and Fluid Mechanics Conference, Australia, Adelaide, 5-9 December 1977.

[6] C hen J., Fletcher D.F., Haynes B.S., Validation of the cobra probe using turbulence measurements in a fully developed pipe flow. Proc. 13th Australasian Fluid Mechanics Conference, 13-18 Dec, eds. M. C. Thompson & K. Hourigan, Monash University, Melbourne, Australia, 1998, Vol. 1, 385-388.

[7] C hen T.Y., Liou L.R., Blockage corrections in wind tunnel tests of small horizontal-axis wind turbines. Experimental Thermal and Fluid Science, Vol. 35(3), 2011, 565-569.

[8] C orkery S., Vertical axis wind turbine with new variable pitch blades, Project Report 2013-ME18, October 2013.

[9] Fitzgerald R., Wind tunnel blockage corrections for propellers, Master Thesis, University of Maryland, 2007.

[10] Gilbert B.L., Foreman K.M., Experimental demonstration of the diffuser-augmented wind turbine concept, Journal of Energy, Vol. 3(4), 1979, 235-240.

[11] Glauert H., Durand W.F. (Ed.), Aerodynamic theory, “Airplane propellers”, Vol. IV, Division I, Chapter VII, Section 4, Julius Springer, Berlin 1935, 169-360.

[12] H and M.M., Simms D.A., Fingersh L.J., Jager D.W., Cotrell J.R., Schreck S., Larwood S.M., Unsteady aerodynamics experiment phase VI: wind tunnel test configurations and available data campaigns, Technical Report NREL/TP-500-29955, NREL National Renewable Energy Laboratory, USA 2001.

[13] H ooper J.D., Musgrove A.R., Multi-hole pressure probes for the determination of the total velocity vector in turbulent single-phase flow, Proc. 4th International Symposium on Transport Phenomena in Heat and Mass Transfer, ed. J. A. Reizes, Pacific Centre of Thermal-Fluids Engineering, Sydney, Australia 1991, Vol. 4, 1364.

[14] I mraan M. Aerodynamic analysis of a wind turbine with telescopic blades, PhD thesis, Mechanical Engineering Department, The University of Auckland, New Zealand, 2013.

[15] I mraan M., Sharma R.N., Flay R.G.J., Wind tunnel testing of a wind turbine with telescopic blades: The influence of blade extension, Energy, Vol. 53, 2013, 22-32.

[16] I mraan M, Sharma, R.N., Flay, R.G.J. Wind tunnel testing of a wind turbine with telescopic blades, Proc. 13th International Conference on Wind Engineering, Amsterdam, The Netherlands, July 10-15, 2011.

[17] S orensen J.N., Wen Zhong Shen, Mikkelsen R., Wall correction model for wind tunnels with open test section, AIAA Journal, Vol. 44(8), 2006, 1890-1894.

[18] L indley D., Flay R.G.J., Bowen A.J., Field measurements of the characteristics of a rural boundary-layer near the ground: Part I; The measured data, Proc. 6th Australasian Conference on Hydraulics and Fluid Mechanics, Adelaide, Australia, Vol. 1, 1977, 182-185.

[19] Whale J., Papadopoulos K.H., Anderson C.G., Helmis C.G., Skyner D.J., A study of the near wake structure of a wind turbine comparing measurements from laboratory and full-scale experiments, Solar Energy, Vol. 56, 1996, 621-633.

[20] Phillips D.G., Richards P.J., Flay R.G.J., CFD Modelling and the development of the diffuser augmented wind turbine, Wind and Structures, Vol. 5(2-4), 2002, 267-276.

[21] Phillips D.G., An investigation on diffuser augmented wind turbine design, PhD thesis, School of Engineering, The University of Auckland, New Zealand 2003.

[21] Ross I.J., Wind tunnel blockage corrections: an application to vertical-axis wind turbines. MSc Thesis, University of Dayton, Dayton, Ohio, May 2010.

[22] Ross I.J., Altman A., Wind tunnel blockage corrections: Review and application to Savonius vertical-axis wind turbines, Journal of Wind Engineering and Industrial Aerodynamics, Vol. 99, 2011, 523-538.

[23] S chepers J.G., Snel H., Model experiments in controlled conditions – final report. Technical Report, ECN-E-07-042, ECN Wind Energy, The Netherlands 2007.

[24] S nel H., Schepers J.G., Montgomerie B., The MEXICO projec (Model EXperiments In Controlled cOnditions): the data base and first results of data processing and interpretation, Journal of Physics: Conference Series, Vol. 75, 2007.

[25] T amura Y., Kareem A. (Eds.), Advanced structural wind engineering, Springer, Japan 2013.

[26] Vermeer L.J., Sørensen J.N., Crespo A., Wind turbine wake aerodynamics, Progress in Aerospace Sciences, Vol. 39, 2003, 467-510.

[27] Wilson R.E., Lissaman P.B.S., Walker S.N., Aerodynamic performance of wind turbines – Final report, Report ERDA/NSF/04014-76/1, Department of Mechanical Engineering, Oregon State University, Corvallis, Oregon. Available from NTIS, U.S. Department of Commerce, Springfield, Virginia 22161, USA.

[28] W orld Wind Energy Association, WWEA., World Wind Energy Half Year Report, 2014, http://www.wwindea.org/home/index.php 2014.