叶片数及弦长对升力型垂直轴风力机的影响

The impact of blade number and chord length on lift-type vertical-axis wind turbine

文章基于非对称翼型NACA4415,以功率系数为依据,以CFD仿真为手段,研究了在不同尖速比下叶片数与叶片弦长对升力型垂直轴风力机气动性能的影响,以及不同尖速比和叶轮实度不同时,垂直轴风力机功率系数的变化。研究结果显示,该类升力型垂直轴风力机叶轮实度取0.25~0.45,尖速比λ取2.5~3.4时,具有较高的功率系数。流场分析表明,当叶片弦长与叶片数的变化对流场的扰动能力小于垂直轴风力机从流场中获取风能的能力时,叶片弦长与叶片数的变化会增加垂直轴风力机的功率系数;反之,垂直轴风力机的功率系数降低。该研究为此类20 k W垂直轴风力机的设计与选型提供依据。

In order to provide a basis for the design of similar vertical axis wind turbine,this essay analyses the impact of blades of different number and chord length of different sizes on aerodynamic performance of a 20 kilowatts lift-type vertical-axis wind turbine made of non-symmetrical airfoil through the method of CFD, as well as the variation of the vertical axis wind turbine power coefficient under different tip speed ratio and impeller solidity. It is found that the vertical-axis wind turbine reaches a higher power coefficient with the impeller solidity from 0.25 to 0.45 and the tip speed ratio from 2.5 to 3.4. In addition, it is observed that the change of the number and chord length of the blade will increase the power coefficient of a vertical axis wind turbine when their disturbance ability is inferior to the vertical-axis wind turbine＇s ability of obtaining wind energy from the flow field. On the reverse position, this change would decrease the power coefficient.