考虑风-沙双向耦合作用大型风力机体系气动力分布研究

A study on the aerodynamic distribution of a large wind turbine system considering wind-sand coupling effect

大型风力机体系属于典型风敏感结构,在风沙条件下易产生极端荷载效应,沙粒的附着亦会影响风的湍流特征并对体系产生附加冲击力,现行规范和文献均缺乏对大型风力机体系风-沙运动特征的系统研究。以南京航空航天大学自主研发的5 MW水平轴风力机为对象,采用改进的k-ε湍流模型模拟来流风场,同时添加DPM自定义沙粒模型实现与来流空气的双相耦合,基于中、强、特强沙尘暴天气典型风速与沙粒粒径的组合工况,系统分析风-沙共同作用下水平轴风力机叶片与塔架的三维流场特性、表面沙粒分布、压力系数与载荷分布,最终提炼出风-沙荷载特征值随环境参数的变化规律。研究表明:相较于风荷载,沙荷载主要对风力机塔架中下部产生冲击作用;风沙共同作用后,大粒径沙粒在风力机塔架迎风面底部产生的荷载效应尤为显著,部分区域沙压系数可达0.517;沙粒冲击荷载与风荷载的比值最高可达22.57%。主要研究结论可为大型风力机结构风沙荷载取值提供科学依据。

A large-scale wind turbine system is a typical wind-sensitive structure,and it is prone to extreme load effects under wind and sand conditions.Adhesion of sand particles will also affect the turbulence characteristics of the wind and cause additional impact on the system.Current regulations and literature are lacking on large-scale wind turbine systems.Taking the 5 MW horizontal-axis wind turbine independently developed by Nanjing University of Aeronautics and Astronautics as the object,a modified k-εturbulence model was used to simulate the flow wind field,and a DPM-defined sand model was added to realize the biphase coupling with the incoming air.Combing typical wind speed and sand particle size in strong and extraordinarily strong dust and dust storms,systematic analysis of three-dimensional flow field characteristics,surface sand distribution,pressure coefficient and load distribution of wind turbine blades and towers under the combined action of wind and sand was performed.Finally,the effect of wind-sand load characteristics on the change of environmental parameters was obtained.The research shows that:compared with wind load,sand load mainly impacts the middle and lower part of the wind turbine tower;after the wind and sand work together,the load effect of large-size sand particles on the bottom of the wind turbine tower is particularly significant.The sand pressure coefficient can reach 0.517;the ratio of sand impact load to wind load can reach up to 22.57%.