阵风工况下多台风力机尾流效应的非定常特性

Unsteady characteristics of wake effect for multiple wind turbines under gust wind condition

风力机实际运行中入流工况复杂,风电场中多台风力机之间的尾流效应呈现高度非定常特性,下游风力机的气动载荷亦会因此受到严重影响。本文开展了阵风工况下多台风力机尾流效应的非定常特性研究。首先,建立了LES耦合致动线模型方法,以Nibe风力机为算例验证了方法的可行性和准确性,并研究了单台风力机尾流速度的发展规律;然后,以NREL 5 MW大型风力机为例,开展了多台风力机在阵风工况下的数值模拟,获得了非定常尾流效应和尾流干扰特性,揭示了尾流中阵风涡系的发展演变规律;最后,分析总结了阵风工况下的风力机气动载荷特性。研究内容及结论对风电场布局和风力机载荷强度设计具有指导意义。

The actual operating conditions of wind turbines are complex,which leads to strong unsteady characteristics between wind turbines in the wind farm,and causes unsteady aerodynamic load of the upstream and downstream wind turbines due to the unsteady wake effect.In this study,the unsteady characteristics for the wake effect of multiple wind turbines are investigated under the gust wind condition.Firstly,an unsteady wake simulation method is established by coupling the LES(large eddge simulation)and the actuator line model,and the feasibility and accuracy are verified using the Nibe wind turbine.Meanwhile,the development characteristics of a single wind turbine wake is unveiled.Then,taking the NREL 5 MW wind turbine as an example,numerical simulations are performed for multiple wind turbines under the gust wind condition.The characteristics of unsteady wake effects and the development mechanism of the wake vortex structures under the gust wind condition are discovered.Finally,aerodynamic load characteristics of the upstream and downstream wind turbines are analyzed and summarized under the gust wind condition.The present analyses and results are significant in guiding the wind farm layout and wind turbine design.