基于U-ABL理论屋顶风力机微观选址数值方法探究

针对国际能源署Task27项目子课题——复杂城市建筑环境屋顶风力机微观选址数值分析方法研究,引入了较传统指数分布更精确、更适宜城市建筑环境的城市大气边界层(U-ABL)理论,探索性提出一种基于城市大气边界层内建筑屋顶风湍流特性分析的屋顶风力机微观选址的数值研究分析新方法.建立了呼和浩特南郊某建筑模型及适宜当地的相关入流函数;计算、分析了建筑屋顶各参考分析点的湍流强度、风加速因子、湍流厚度及理想功率增大因子等湍流特性参数随高度的变化规律;确定了屋顶选定水平轴风力机最佳安装位置为建筑前沿点、最佳安装高度约为1.50倍建筑高度;该实例验证了所提新方法的可行性,能为城市环境风湍流特征分析提供理论依据及新思路,亦对建筑屋顶风力机的微观选址具有理论和工程应用价值.

Study on numerical method for roof mounted wind turbine micrositing based on U-ABL

Based on project IEA Task 27- study on numerical method for wind turbines micrositing on top of buildings in complex urban building environment, the urban atmospheric boundary layer(U-ABL)is involved, and a new CFD numerical analysis method is explored for micrositing of small building-mounted wind turbines. In the method, the wind turbulent characteristics are analyzed by using U-ABL, consequently, more accurate and suitable inflow condition is established for the urban building environment. By making use of this method, a building in southern suburb in Hohhot city is modelled in CFD and a suitable inflow condition is included by UDF. Then, the turbulent characteristic parameters such as turbulent intensity, wind acceleration factor, average turbulent boundary layer thickness and ideal power amplifying factor in the vertical direction above the building are predicted and analyzed. The results turn out that the optimum installation location is at the leading edge of the building for a horizontal axis wind turbines and the turbines should be above the building as high as 1.50 times the building height. The case has confirmed the feasibility of the new numerical method, and provides a new idea for analyzing the wind turbulent characteristics. Meanwhile, the method also has theoretical and practical significance for small building-mounted wind turbines micrositing.