風能在世界上被認為是重要的再生能源之一。在都市中，因為建築物不規則的排列分佈，小型的風力發電機在家庭式的電力網中扮演了一個非常重要的角色。在本研究中，一個名為混合軸的新型設計的風力發電機在低速開放式的風洞內在雷諾數為 42900、57100、71400的情況下測試其功率輸出表現。其結果將和傳統的直線翼垂直軸風力發電機做比較。性能分析的項目主要分為靜態表現、動態表現、葉片力量測等三大部分。從靜態或者動態表現都可發現到混合軸風力發電機不論是啟動能力或是功率係數皆優於傳統直線翼風力發電機。最後在水平葉片上所量測到的切線力更證明了為何混合軸風力發電機相較於傳統直線翼風力發電機更具有優勢。

Wind energy has been considered as one of the primary renewable energy sources globally. In urban areas, due to the irregular arrangement of buildings, small scale wind turbine plays an important roles for household energy grid. In this study, a newly designed small scale wind turbine namely cross-axis wind turbine (CAWT) was examined experimentally on the power performance in a low speed, open-loop circuit wind tunnel at Reynolds numbers of Re=42900, 57100 and 71400. The results were compared to a traditional straight-bladed vertical axis wind turbine (VAWT). The performance analyses are evaluated in terms of static performance, dynamic performance, and blade force measurement. The results of static and dynamic performances indicate that CAWT has not only better starting characteristics but also higher power coefficients over VAWT. The tangential forces measurement on the horizontal blade of CAWT proves its superior power performance compared to VAWT.

Reference

1. P. Gardner, A.G., L.F. Hansen, P. Jamieson, C. Morgan, F. Murray. Wind energy the facts – part I – technology. 2009.
2. Gebhardt, C., S. Preidikman, and J. Massa, Numerical simulations of the aerodynamic behavior of large horizontal-axis wind turbines. International Journal of Hydrogen Energy, 2010. 35(11): p. 6005-6011.
3. Dai, J.C., et al., Aerodynamic loads calculation and analysis for large scale wind turbine based on combining BEM modified theory with dynamic stall model. Renewable Energy, 2011. 36(3): p. 1095-1104.
4. Toja-Silva, F., A. Colmenar-Santos, and M. Castro-Gil, Urban wind energy exploitation systems: Behaviour under multidirectional flow conditions—Opportunities and challenges. Renewable and Sustainable Energy Reviews, 2013. 24: p. 364-378.
5. Fleck, B. and M. Huot, Comparative life-cycle assessment of a small wind turbine for residential off-grid use. Renewable Energy, 2009. 34(12): p. 2688-2696.
6. Bai, C.J., et al., Design of 10 kW Horizontal-Axis Wind Turbine (HAWT) Blade and Aerodynamic Investigation Using Numerical Simulation. Procedia Engineering, 2013. 67: p. 279-287.
7. Hsiao, F.-B., C.-J. Bai, and W.-T. Chong, The performance test of three different horizontal axis wind turbine (HAWT) blade shapes using experimental and numerical methods. Energies, 2013. 6(6): p. 2784-2803.
8. Hirahara, H., et al., Testing basic performance of a very small wind turbine designed for multi-purposes. Renewable Energy, 2005. 30(8): p. 1279-1297.
9. Kishore, R.A. and S. Priya, Design and experimental verification of a high efficiency small wind energy portable turbine (SWEPT). Journal of Wind Engineering and Industrial Aerodynamics, 2013. 118: p. 12-19.
10. Kang, H.S. and C. Meneveau, Direct mechanical torque sensor for model wind turbines. Measurement Science and Technology, 2010. 21(10): p. 1-10.
11. Krogstad, P.-Å. and J.A. Lund, An experimental and numerical study of the performance of a model turbine. Wind Energy, 2012. 15(3): p. 443-457.
12. Cho, T. and C. Kim, Wind tunnel test results for a 2/4.5 scale MEXICO rotor. Renewable Energy, 2012. 42: p. 152-156.
13. Kishore, R.A., T. Coudron, and S. Priya, Small-scale wind energy portable turbine (SWEPT). Journal of Wind Engineering and Industrial Aerodynamics, 2013. 116: p. 21-31.
14. Hsiao, F.-B., C.-J. Bai, and W.-T. Chong, The Performance Test of Three Different Horizontal Axis Wind Turbine (HAWT) Blade Shapes Using Experimental and Numerical Methods. Energies, 2013. 6(6): p. 2784-2802.
15. P.Monteiro, J., et al., Wind tunnel testing of a horizontal axis wind turbine rotor and comparison with simulations from two Blade Element Momentum codes. Journal of Wind Engineering and Industrial Aerodynamics, 2013. 123: p. 99-106.
16. Bai, C.-J., et al., System Integration of the Horizontal-Axis Wind Turbine: The Design of Turbine Blades with an Axial-Flux Permanent Magnet Generator. Energies, 2014. 7(11): p. 7773-7793.
17. Cho, T. and C. Kim, Wind tunnel test for the NREL phase VI rotor with 2 m diameter. Renewable Energy, 2014. 65: p. 265-274.
18. Roy, S. and U.K. Saha, Wind tunnel experiments of a newly developed two-bladed Savonius-style wind turbine. Applied Energy, 2015. 137: p. 117-125.
19. Rossander, M., et al., Evaluation of a blade force measurement system for a vertical axis wind turbine using load cells. Energies, 2015. 8(6): p. 5973-5996.
20. Li, Q.a., et al., Effect of a number of blades on aerodynamic forces on a straight-bladed vertical axis wind turbine. Energy, 2015. 90: p. 784-795.
21. McLaren, K., S. Tullis, and S. Ziada, Measurement of high solidity vertical axis wind turbine aerodynamic loads under high vibration response conditions. Journal of Fluids and Structures, 2012. 32: p. 12-26.
22. LI, Q.a., et al., Effect of blade number on flow around straight-bladed vertical axis wind turbine The Japan Society of Mechanical Engineers, 2014. 80(816): p. FE0223-FE0223.
23. Lin, T.-H. and Y.-Y. Tsui, Qualitative Analysis of the Performance of a Vertical-Axis Wind Turbine. 2010.
24. Hsieh, C., J. Miao, and J. Chen, Experimental and numerical studies of torque and power generation in a vertical axis wind turbine. National Cheng Kung University, 2009.
25. Takao, M., et al., A straight-bladed vertical axis wind turbine with a directed guide vane row — Effect of guide vane geometry on the performance —. Journal of Thermal Science, 2009. 18(1): p. 54-57.
26. Howell, R., et al., Wind tunnel and numerical study of a small vertical axis wind turbine. Renewable energy, 2010. 35(2): p. 412-422.
27. Zheng, P.-l., Three-Dimensional and Arm Effects on Aerodynamics Simulation for the Slant-H-Rotor Vertical Axis Wind Turbine. 2011.
28. Brusca, S., R. Lanzafame, and M. Messina, Design of a vertical-axis wind turbine: how the aspect ratio affects the turbine’s performance. International Journal of Energy and Environmental Engineering, 2014. 5(4): p. 333-340.
29. Liu, W.-Q., Three-dimensional Aerodynamic Model with Viscous Turbulent Effects on Vertical-axis Wind Turbine. 1994.
30. McCroskey, W., Unsteady airfoils. Annual review of fluid mechanics, 1982. 14(1): p. 285-311.
31. Kim, D. and M. Gharib, Efficiency improvement of straight-bladed vertical-axis wind turbines with an upstream deflector. Journal of Wind Engineering and Industrial Aerodynamics, 2013. 115: p. 48-52.
32. Chong, W., et al., The design, simulation and testing of an urban vertical axis wind turbine with the omni-direction-guide-vane. Applied Energy, 2013. 112: p. 601-609.
33. Ng, E., et al., Improving the wind environment in high-density cities by understanding urban morphology and surface roughness: a study in Hong Kong. Landscape and Urban Planning, 2011. 101(1): p. 59-74.
34. Ricciardelli, F. and S. Polimeno, Some characteristics of the wind flow in the lower urban boundary layer. Journal of Wind Engineering and Industrial Aerodynamics, 2006. 94(11): p. 815-832.
35. Ledo, L., P. Kosasih, and P. Cooper, Roof mounting site analysis for micro-wind turbines. Renewable Energy, 2011. 36(5): p. 1379-1391.
36. Lu, L. and K.Y. Ip, Investigation on the feasibility and enhancement methods of wind power utilization in high-rise buildings of Hong Kong. Renewable and Sustainable Energy Reviews, 2009. 13(2): p. 450-461.
37. Eriksson, S., H. Bernhoff, and M. Leijon, Evaluation of different turbine concepts for wind power. Renewable and Sustainable Energy Reviews, 2008. 12(5): p. 1419-1434.
38. Kao, Y.-M., Calibration of the ABRI Environment Wind Tunnel and Experimental Study of 2-D Bluff-Body Aerodynamic Flows. Master of Science Thesis, 2005: p. 1-141.
39. Cook, N.J., A boundary layer wind tunnel for building aerodynamics. Journal of Wind Engineering and Industrial Aerodynamics, 1975. 1: p. 3-12.
40. Manwell, J.F., J.G. McGowan, and A.L. Rogers, Wind Energy Explained: Theory, Design and Application. 2002: John Wiley & Sons, Ltd.
41. Islam, M., D.S.-K. Ting, and A. Fartaj, Aerodynamic models for Darrieus-type straight-bladed vertical axis wind turbines. Renewable and Sustainable Energy Reviews, 2008. 12(4): p. 1087-1109.
42. Oler, J., et al., Dynamic stall regulation of the Darrieus turbine. 1983: Citeseer.
43. Chen, T. and L. Liou, Blockage corrections in wind tunnel tests of small horizontal-axis wind turbines. Experimental Thermal and Fluid Science, 2011. 35(3): p. 565-569.
44. Bishop, J.D. and G.A. Amaratunga, Evaluation of small wind turbines in distributed arrangement as sustainable wind energy option for Barbados. Energy Conversion and Management, 2008. 49(6): p. 1652-1661.
45. Rae, W.H. and A. Pope, Low-speed wind tunnel testing. 1984: John Wiley.
46. Templin, R., Aerodynamic performance theory for the NRC vertical-axis wind turbine. 1974, National Aeronautical Establishment, Ottawa, Ontario (Canada).
47. Moffat, R.J., Describing the uncertainties in experimental results. Experimental thermal and fluid science, 1988. 1(1): p. 3-17.
48. Blackwell, B.F., R.E. Sheldahl, and L.V. Feltz, Wind tunnel performance data for the Darrieus wind turbine with NACA 0012 blades. 1976, Sandia Labs., Albuquerque, N. Mex.(USA).
49. Sheldahl, R.E. and P.C. Klimas, Aerodynamic characteristics of seven symmetrical airfoil sections through 180-degree angle of attack for use in aerodynamic analysis of vertical axis wind turbines. 1981, Sandia National Labs., Albuquerque, NM (USA).