(1.Research Center for Renewable Energy Generation Engineering， Ministry of Education, Hohai University, Nanjing, Jiangsu 210098, China; 2. National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Hohai University, Nanjing, Jiangsu 210098, China; 3. North China Electric Power Research Institute Co. Ltd., Beijing 100045, China)
Abstract：In order to know more information about the complex turbulent field in vertical axis Darrieus rotors, the unsteady k-ω turbulence model and sliding mesh technique were used to model the aerodynamic characteristics and twodimensional flow field in this kind of wind rotor with straight blades of NACA0012 airfoil. The aerodynamic flow field around the blades and torque characteristics of rotor at different rotational speeds were investigated. The flow fields in the rotors at different time instances i.e. in different azimuth angles, were presented, the results revealed that the relation angle of attack with azimuth angle is not a sinusoid. The torque curves indicated that a maximum torque was generated when the blades were at the 90° azimuth angle, the blades at downstream of the rotor had a near zero or even a small negative torque, suggesting the angles of attack there were very small. At the same wind freestream velocity, the wind velocity in the rotor was reduced with increasing rotational speed. The torque curves of upstream blades showed a maximum torque at a rotational speed when the speed was increased, however, the torque on downstream blades decreased steadily and exhibited a considerable variation. The contrast of numerical results and test results prove that the turbulence model with slip grid technology can reflect the flow field in a vertical Darrieus wind turbine with straight blades.
［1］Islam Mazharul, Ting David S-K, Fartaj Amir. Aerodynamic models for Darrieustype straightbladed vertical axis wind turbines［J］. Renewable and Sustainable Energy Reviews, 2008,12(4):1087-1109.［2］杨从新,巫发明,张玉良. 基于滑移网格的垂直轴风力机非定常数值模拟［J］.农业机械学报,2009,40(6):98-102.Yang Congxin, Wu Faming, Zhang Yuliang. Numerical simulation on unsteady rotated flow of a vertical axis wind turbine based on moving meshes［J］. Transactions of the Chinese Society for Agriculture Machinery, 2009, 40(6): 98-102. (in Chinese)［3］金雪红, 梁武科, 李常. 风速对垂直轴风力机风轮气动性能的影响［J］. 流体机械,2010,38(4):45-49.Jin Xuehong, Liang Wuke, Li Chang. Aerodynamic performance of the vertical axis wind turbine on wind speed［J］. Fluid Machinery, 2010,38(4): 45-49.(in Chinese)［4］阳志钦,崔文篆. 垂直轴风力机二维非定常流场数值模拟［J］. 现代制造工程, 2009(8):56-59.Yang Zhiqin, Cui Wenzhuan. Numerical simulation for 2D unsteady flow around the vertical axis wind turbine［J］. Turbine Modern Manufacturing Engineering, 2009(8): 56-59.(in Chinese)［5］姚激, 黄剑峰, 彭明军, 等. 变攻角垂直轴风力机三维定常流场数值模拟［J］. 机械与电子, 2011(7):21-24.Yao Ji, Huang Jianfeng, Peng Mingjun, et al. Numerical simulation on 3D steady for different angles of attack of vertical axis wind turbine［J］. Mechanical and Electronics, 2011(7):21-24.(in Chinese)［6］Jiang Zhichao, Doi Yasuaki, Zhang Shuyou. Numerical investigation on the flow and power of smallsized multibladed straight Darrieus wind turbine［J］. Journal of Zhejiang University Science A, 2007,8(9):1414-1421.［7］Camporeale Sergio M, Magi Vinicio. Streamtube model for analysis of vertical axis variable pitch turbine for marine currents energy conversion［J］. Energy Conversion and Management, 2000,41(16):1811-1827.［8］Schnborn Alessandro, Chantzidakis Matthew. Development of a hydraulic control mechanism for cyclic pitch marine current turbines［J］. Renewable Energy, 2007,32(4):662-679.［9］刘磊, 徐建中. 湍流模型对风力机叶片气动性能预估的影响［J］. 工程热物理学报, 2009,30(7):1136-1139.Liu Lei, Xu Jianzhong. The effects of turbulence model on the aerodynamic performance prediction of wind turbine blade［J］. Journal of Engineering Thermophysics, 2009, 30(7):1136-1139.(in Chinese)［10］赵振宙, 郑源, 宋晨光, 等. 升阻混合风轮的性能规律［J］. 排灌机械工程学报, 2011,29(6):508-512.Zhao Zhenzhou, Zheng Yuan, Song Chenguang, et al. Performance of liftdrag combined wind turbine rotor［J］. Journal of Drainage and Irrigation Machinery Engineering, 2011,29(6):508-512.(in Chinese)［11］Raciti Castelli M, Englaro A, Benini E. The Darrieus wind turbine: Proposal for a new performance prediction model based on CFD［J］. Energy, 2011,36(8):4919-4934.
