為了提高都市區域的風能發電量，本研究提出了螺旋式交叉軸風力發電機(Helical-CAWT)。本試驗中，螺旋葉式交叉軸風力發電機將於風洞中和木製網格、導流板及障礙物在不同雷諾數(Re)下進行測試，以進行風力發電機組於屋頂運行的模擬，並且將透過網格及三種導流板角度(0、30、45度)和不同形狀的障礙物(圓筒型、尖角型、平面型)來進行紊流(T.I.)、垂直向風速(v)、來流方向風速(u)以及螺旋葉式交叉軸風力發電機的動態及靜態性能討論。並且發現在0度導流板和平面型障礙物的影響下螺旋葉式交叉軸風力發電機有最高的風機效率(Cp)提升和最高的自由轉動測試轉速。

For enhancing the wind power generation in urban area, the Helical-cross axis wind turbine (Helical-CAWT) was proposed in this study. The performance of Helical-CAWT was examined through wind tunnel experiment, with the additions of mesh, decline board and obstacles operating at various Reynolds numbers (Re), for the purpose of mimicking the turbine operation at the rooftop of building. The turbulence intensities (T.I.), vertical wind speeds (v) and streamwise flow velocities (u) as well as the dynamic and static performances of Helical-CAWT were investigated through the applications of mesh as well as three different angles of decline board (0°, 30° and 45°) and three shapes of obstacles (cylinder, pitch and flat). The highest improvement of peak power coefficient (Cp) and greatest free-run rotational speed for Helical-CAWT were found with the existences of 0° decline board and flat shape obstacle.

1. GWEC. Global Status of Wind Power. 2016; Available from: http://gwec.net/global-figures/wind-energy-global-status/.
2. Pagnini, L.C., M. Burlando, and M.P. Repetto, Experimental power curve of small-size wind turbines in turbulent urban environment. Applied Energy, 2015. 154: p. 112-121.
3. Shahizare, B., et al., Novel investigation of the different Omni-direction-guide-vane angles effects on the urban vertical axis wind turbine output power via three-dimensional numerical simulation. Energy Conversion and Management, 2016. 117: p. 206-217.
4. Li, Q.a., et al., Study on power performance for straight-bladed vertical axis wind turbine by field and wind tunnel test. Renewable Energy, 2016. 90: p. 291-300.
5. Eboibi, O., L.A.M. Danao, and R.J. Howell, Experimental investigation of the influence of solidity on the performance and flow field aerodynamics of vertical axis wind turbines at low Reynolds numbers. Renewable Energy, 2016. 92: p. 474-483.
6. Howell, R., et al., Wind tunnel and numerical study of a small vertical axis wind turbine. Renewable energy, 2010. 35(2): p. 412-422.
7. Peng, H. and H. Lam, Turbulence effects on the wake characteristics and aerodynamic performance of a straight-bladed vertical axis wind turbine by wind tunnel tests and large eddy simulations. Energy, 2016. 109: p. 557-568.
8. Didane, D.H., et al., Performance evaluation of a novel vertical axis wind turbine with coaxial contra-rotating concept. Renewable Energy, 2018. 115: p. 353-361.
9. Battisti, L., et al., Experimental benchmark data for H-shaped and troposkien VAWT architectures. Renewable Energy, 2018. 125: p. 425-444.
10. Ayhan, D. and Ş. Sağlam, A technical review of building-mounted wind power systems and a sample simulation model. Renewable and Sustainable Energy Reviews, 2012. 16(1): p. 1040-1049.
11. Ricci, A., et al., Wind tunnel measurements of the urban boundary layer development over a historical district in Italy. Building and Environment, 2017. 111: p. 192-206.
12. Adaramola, M. and P.-Å. Krogstad, Experimental investigation of wake effects on wind turbine performance. Renewable Energy, 2011. 36(8): p. 2078-2086.
13. Ledo, L., P. Kosasih, and P. Cooper, Roof mounting site analysis for micro-wind turbines. Renewable Energy, 2011. 36(5): p. 1379-1391.
14. Becker, S., H. Lienhart, and F. Durst, Flow around three-dimensional obstacles in boundary layers. Journal of Wind Engineering and Industrial Aerodynamics, 2002. 90(4-5): p. 265-279.
15. Abohela, I., N. Hamza, and S. Dudek, Effect of roof shape, wind direction, building height and urban configuration on the energy yield and positioning of roof mounted wind turbines. Renewable Energy, 2013. 50: p. 1106-1118.
16. Chong, W.T., et al., Performance assessment of a hybrid solar-wind-rain eco-roof system for buildings. Energy and Buildings, 2016. 127: p. 1028-1042.
17. Chong, W.T., et al., Cross axis wind turbine: Pushing the limit of wind turbine technology with complementary design. Applied Energy, 2017. 207: p. 78-95.
18. Wong, K.H., et al., Experimental and simulation investigation into the effects of a flat plate deflector on vertical axis wind turbine. Energy Conversion and Management, 2018. 160: p. 109-125.
19. Wang, W.-C., W.T. Chong, and T.-H. Chao, Performance analysis of a cross-axis wind turbine from wind tunnel experiments. Journal of Wind Engineering and Industrial Aerodynamics, 2018. 174: p. 312-329.
20. Wang, W.C., T.T. Wang, and W.T. Chong, The effects of unsteady wind on the performances of a newly developed cross-axis wind turbine: A wind tunnel study. Renewable Energy, 2018.
21. Scheurich, F. and R.E. Brown, Modelling the aerodynamics of vertical‐axis wind turbines in unsteady wind conditions. Wind Energy, 2013. 16(1): p. 91-107.
22. Rahman, M., et al., Numerical and Experimental Investigation of Aerodynamic Performance of Vertical-Axis Wind Turbine Models with Various Blade Designs. Journal of Power and Energy Engineering, 2018. 6(05): p. 26.
23. Montelpare, S., et al., Experimental study on a modified Savonius wind rotor for street lighting systems. Analysis of external appendages and elements. Energy, 2018. 144: p. 146-158.
24. Tummala, A., et al., A review on small scale wind turbines. Renewable and Sustainable Energy Reviews, 2016. 56: p. 1351-1371.
25. King, L.V., XII. On the convection of heat from small cylinders in a stream of fluid: Determination of the convection constants of small platinum wires with applications to hot-wire anemometry. Phil. Trans. R. Soc. Lond. A, 1914. 214(509-522): p. 373-432.
26. Taylor, F.C., A suggested method for measuring turbulence. 1931.
27. Kao, Y., Calibration of the ABRI environment wind tunnel and experimental study of 2-D bluff-body aerodynamic flows. 2005, MS Thesis, Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, Taiwan, ROC.
28. Bearman, P. and T. Morel, Effect of free stream turbulence on the flow around bluff bodies. Progress in aerospace sciences, 1983. 20(2-3): p. 97-123.
29. Hsieh, W., et al. Wind Tunnel Analysis on Performance of H-Rotor VAWTs with NACA 64xx Blades. in Advanced Materials Research. 2012. Trans Tech Publ.
30. Hsieh, W., et al. Experimental study on performance of vertical axis wind turbine with NACA 4-digital series of blades. in Advanced Materials Research. 2012. Trans Tech Publ.
31. Tjiu, W., et al., Darrieus vertical axis wind turbine for power generation I: Assessment of Darrieus VAWT configurations. Renewable Energy, 2015. 75: p. 50-67.
32. Roy, S. and U.K. Saha, An adapted blockage factor correlation approach in wind tunnel experiments of a Savonius-style wind turbine. Energy Conversion and Management, 2014. 86: p. 418-427.
33. Hackett, J., D. Wilsden, and D. Lilley, Estimation of tunnel blockage from wall pressure signatures: a review and data correlation. 1979.
34. Pope, A. and J.J. Harper, Low Speed Wind Tunnel Testing, John Willy and Sons. New York, 1966.
35. Peckham, D. and S. Atkinson, Preliminary results of low speed wind tunnel tests on a gothic wing of aspect ratio 1.0. 1957: Royal Aircraft Establishment.
36. Wu, P.-H., Investigation of Velocity Measurement in Turbulent Flow by Intrusive Anemometry. Institute of Aeronautics and Astronautics National Cheng Kung University Tainan, Taiwan, R.O.C., 2013: p. 1-115.
37. Sponfeldner, T., et al., The structure of turbulent flames in fractal-and regular-grid-generated turbulence. Combustion and Flame, 2015. 162(9): p. 3379-3393.