尾缘射流式垂直轴风力机气动特性数值分析

Numerical analysis of aerodynamic characteristic for vertical axis wind turbine of trailing edge jet

摘要:

为抑制翼型表面流动分离并提高风力机叶片气动性能,将可靠性较高的吹气射流技术应用于垂直轴风力机叶片尾缘。采用数值模拟方法分析不同尾缘射流角度对垂直轴风力机风能利用系数、力矩系数及单叶压力与整机涡量的影响。模拟结果表明:在最佳尖速比（2.63）时,10°射流可以有效降低翼型尾缘脱落涡频率,有效控制叶片尾迹效应,整机效率及运行稳定性均优于0°尾缘射流式垂直轴风力机；在较低尖速比时,风力机单叶力矩峰值均集中在120°相位角,尾缘10°射流对整机力矩系数有显著提升效果；在较高尖速比时,单叶翼型压力面存在较大正压区,风能利用系数最大可提高11%左右,气动性能明显优于无射流垂直轴风力机。尾缘射流降低了风力机叶片所需承受的轴向载荷,提高了风力机输出功率。不同角度尾缘射流均能有效降低叶片表面流动损失进而延缓流动分离,数值结果为尾缘射流式垂直轴风力机的工程应用提供了部分参考价值。

Abstract:

To restrain the flow separation phenomenon on the airfoil surface and improve the aerodynamic performance of wind turbine blade, the blowing jet technology with high reliability is applied to the blade trailing edge of vertical axis wind turbines (VAWTs). The influence of different jet angles on the wind power coefficient, torque coefficient, single blade pressure and whole vorticity of the wind turbine was analyzed by numerical simulation. The results show that, when the optimum tip-speed ratio is 2.3,0° jet can reduce the shedding vortex frequency effectively and control the wake effect of blade with a better efficiency and operation stability than 0° jet. When the tip-speed ratio is lower, the peak torque of single blade is concentrated on the 120° phase angle, and 10° jet has a noticeable effect on improving the torque coefficient of the whole machine. When the tip-speed ratio is higher, there is a large positive pressure area on the pressure surface of the single blade airfoil, the wind energy utilization coefficient increases by 11% at most, and the aerodynamic performance is superior to that of the non-jet VAWT. The wind turbine reduces the axial load that the blade needs to bear and improves the output power of the wind turbine through trailing edge jet on the whole. The trailing edge jet of different angles reduces the flow loss on the blade surface and delays the flow separation effectively, which is particularly important to enhance the market competitiveness of VAWTs.