垂直轴风力机变桨规律及气动性能优化研究

Study on the rule of pitch change and aerodynamic performance optimization of vertical axis wind turbine

以H型Darrieus垂直轴风力机为研究对象,基于最大切向力原则和Fourier函数,提出了一种适用于不同叶尖速比的变桨策略,即基于最大切向力原则确定最优攻角,进而生成理论变桨规律曲线;同时为保证变桨规律的周期性和便于实施,将理论变桨规律曲线离散成控制点,采用Fourier函数进行二次优化拟合,进而以数值模拟的方式,从垂直轴风力机的静态启动性能及动态输出性能方面研究变桨规律对其气动性能的影响。结果表明,变桨后垂直轴风力机各叶尖速比的功率系数显著提升,且提升效果在叶尖速比较低时尤为显著,最优叶尖速比为1.25,其功率系数峰值提升了13.5%;同时垂直轴风力机各相位角的静态启动性能大幅提升,静态力矩系数最大处较变桨前提升了261.1%。研究结果可为垂直轴风力机的气动性能优化提供参考依据。

Based on the principle of maximum tangential force and Fourier function,it takes Darrieus vertical axis wind turbine of type H as the research object.In other words,the optimal angle of attack is determined based on the principle of maximum tangential force,and the theoretical curve of pitch variation is generated.Meanwhile,in order to ensure the periodicity and ease of implementation of the rule of pitch variation,the control points are discretized from the theoretical pitch curve,and Fourier function is used for quadratic optimization and fitting.Then,the influence of variable pitch rule on the aerodynamic performance of vertical axis wind turbines is studied from the aspects of static start-up performance and dynamic output performance by numerical simulation.The results show that the power coefficient of vertical axis wind turbines is significantly improved at different tip speed ratios,and the improvement effect is particularly significant when the tip speed ratio is low,and the peak power coefficient is increased by 13.5%at the optimal tip speed ratio of 1.25.At the same time,the static starting performance of vertical wind turbine under each phase angle is greatly improved,and the maximum static torque coefficient is increased by 261.1%compared with that before variable pitch.The research results can provide a reference for the optimization of aerodynamic performance of vertical wind turbines.