新一代涡识别方法在大偏航条件下风电机组复杂尾涡辨识中的适用性研究

STUDY ON APPLICABILITY OF NEW GENERATION VORTEX IDENTIFICATION METHOD FOR COMPLEX WAKE VORTEX IDENTIFICATION OF WIND TURBINES UNDER LARGE YAW CONDITIONS

为进一步了解大偏航条件下串列风力机组的复杂尾流特性,采用4种不同的涡识别方法(第一代Vorticity、第二代Q、第三代Liutex、第三代NewOmega)可视化串列风机组的尾涡结构,以探究新一代(第三代)涡识别方法(Liutex、NewOmega)在风力机大偏航条件下的适用性。首先,基于致动线(actuator line,AL)模型和一种局部动态Smagorinsky(localized dynamic Smagorinsky,LDS)亚格子模型,开发一套精度高、计算成本低的水平轴风力机尾流精细化数值模拟框架(AL-LDS耦合模型框架)。其次,选取NREL-5MW风力机为研究对象,将AL-LDS耦合模型的模拟结果与NREL基准值进行对比,从而验证AL-LDS耦合模型的精度。最后,编写最新的第三代涡识别方法(Liutex、NewOmega)后处理程序,并将新一代涡识别方法应用到大偏航条件下串列风力机组的尾涡辨识中,进而分析多机组间的复杂尾涡流动机理。结果表明:(1)AL-LDS耦合模型具有较高的计算精度;(2)第三代涡识别方法同样适用于大偏航条件下风力机尾涡结构的可视化,且可捕捉到尾流中成对的涡脱落现象以及破碎弱涡结构。

To further understand the complex wake characteristics of tandem wind turbines under large yaw conditions,four different vortex identification methods(first generation Vorticity,second generation Q,third generation Liutex,and third generation New Omega)are used to visualize the wake vortex structure of tandem wind turbines,so as to explore the applicability of the new generation(third generation)vortex identification methods(Liutex and New Omega)under large yaw conditions.Firstly,based on the actuator line(AL)model and a localized dynamic Smagorinsky(LDS)sub-grid scale(SGS)model,a refined numerical simulation framework(AL-LDS coupling model framework)for wake simulation of the horizontal-axis wind turbine with high accuracy and low computational cost is developed.Secondly,the NREL-5MW wind turbine is selected as the research object.The simulation results of the AL-LDS coupling model are compared with the NREL reference value to validate the accuracy of the AL-LDS coupling model.Finally,the post-processing program of the latest third generation vortex identification methods(Liutex and New Omega)are compiled,and the new generation vortex identification methods are applied to the wake vortex identification of tandem wind turbines under large yaw conditions,so as to analyze the complex wake vortex flow mechanism between multiple wind turbines.The results show that the AL-LDS coupling model has high simulation accuracy,the third generation vortex identification methods are also suitable for the visualization of wind turbines wake vortex structure under large yaw conditions,and can capture the paired vortex shedding phenomenon and broken weak vortex structures in the wake.