基于正交试验凹槽-襟翼垂直轴风力机数值研究

NUMERICAL STUDY OF VERTICAL AXIS WIND TURBINE WITH DIMPLE-FLAPS BASED ON ORTHOGONAL TEST

为改善垂直轴风力机气动特性,对凹槽-襟翼开展研究。以NACA0021翼型为研究对象,采用正交试验设计对格尼襟翼高度、格尼襟翼位置及凹槽直径等参数进行组合,通过数值计算对垂直轴风力机气动性能与流场结构进行研究,分析凹槽-襟翼流动控制机理及对垂直轴风力机的作用效果。结果表明:格尼襟翼高度是影响垂直轴气动性能的主要因素,且襟翼高度为1.75%c、位置为1.50c及凹槽直径为1.50%c时效果最佳;同时,凹槽-襟翼通过改变尾缘库塔条件以加速翼型吸力面流体流动,从而改善流动分离,增加翼型表面压差,提高垂直轴风力机气动性能;凹槽-襟翼在低尖速比时对垂直轴风力机作用效果较明显,当尖速比为2.33时,凹槽-襟翼垂直轴风力机平均风能利用系数较原始翼型最大可提高35.82%。

In order to improve the aerodynamic characteristics of vertical axis wind turbine,the dimple-flap was studied in this paper.Taking NACA0021 airfoil as the research object,orthogonal experimental design was used to combine the parameters such as Gurney flap height,Gurney flap position and dimple diameter.The aerodynamic performance and flow field structure of vertical-axis wind turbine were studied by numerical calculation,and the dimple-flap flow control mechanism and its effect on vertical axis wind turbine were analyzed.The results show that the height of Gurney flap is the main factor affecting the aerodynamic performance of the vertical axis,and the best effect is achieved when the height of the flap is 1.75%c,the position is 0.05%c and the dimple diameter is 0.15%c.At the same time,dimple-flap can accelerate the flow on the suction surface of airfoil by changing the trailing edge kutta conditions,so as to improve the flow separation,increase the airfoil surface differential pressure,and improve the aerodynamic performance of the vertical axis wind turbine.The effect of dimple-flap on vertical axis wind turbine is more obvious at low tip speed ratio.When the tip speed ratio is 2.33,the average wind energy utilization coefficient of dimple-flap vertical axis wind turbine can increase by 35.82%compared with the original airfoil.