动态风载对尾迹亏损及涡量耗散的影响研究

Influence of Dynamic Wind Load on Wake Loss and Vorticity Dissipation

气流通过高速旋转的叶片会产生复杂的湍流结构,对风力机尾流发展与输出功率造成不利影响。本文对新能源实验基地自然风速进行了实时监测与分析,根据实测变风数据建立了稳定、渐变风、阵风等不同变风阶段的尾迹流场特征非稳态计算模型,探究了不同动态风速变化对尾迹流场速度分布及涡量耗散的影响规律。研究结果表明:相对于稳定入流,动态风载会造成尾迹速度亏损,不同变风阶段沿尾迹发展径向方向上的速度变化梯度存在差异。同时:涡量耗散速度受动态风速变化率影响的敏感度不同,近尾迹区域中心涡与电机绕流引起的湍流掺混会对中心涡量最大值的位置产生影响.相关成果对于提高风轮气动性能、控制尾流发展具有一定的参考价值。

The complex turbulence structure will be produced when the airflow passes through the high-speed rotating blades,which will have a negative impact on the development of the wake and the output power of the wind turbine.The real-time monitoring and analysis of the natural wind speed in the new energy experimental base are carried out in this paper.Based on the measured variable wind data,the unsteady calculation model of wake flow characteristics in different variable wind stages,such as steady,gradual and gusty wind,is established.The influence of different dynamic wind speed changes on the wake flow velocity distribution and vorticity dissipation is explored.The results show that relative to the steady inflow,the dynamic wind load will cause the wake velocity loss,and the velocity gradient along the radial direction of wake development is different in different wind changing stages.At the same time,the sensitivity of the dissipation velocity of vorticity to the change rate of dynamic wind speed is different.The mixing of the central vorticity and the turbulent flow around the motor in the near wake region will affect the position of the maximum value of the central vorticity.The relevant results have certain reference value for improving the aerodynamic performance of wind turbine and controlling the development of wake.