一种水平轴风力机尾流模型及其计算方法

基于现有的尾流模式,提出一种新的尾流计算方法.新的尾流模式将尾流分为近涡区和远涡区,在近涡区,尾涡在选定的扇形截面上解析求出,在其他处通过非线性插值求得.在尾涡中选取有限的离散点数计算诱导速度,减少了计算量,根据流体连续性方程确定尾涡的扩散半径,避免了梢涡半径的不收敛性.通过具体的风力机算例,与刚性尾流模型相比,该方法计算的轴向诱导因子其分布趋势更加合理,验证了该方法的正确性和实用性,为水平轴风力机风轮气动设计和性能计算提供一种有效的尾流模型计算方法.

A wake vortex model for horizontal-axis wind turbine and its calculation method

Based on the existing wake vortex model,a new method was put forward to calculate the wake.The wake was divided into a near vortex zone and a far one in this new wake model.In the former,the wake vortex could be obtained analytically in a selected fan-shaped cross-section while in the latter the wake vortex would be determined by nonlinear interpolation.Selecting limited discrete points in the wake,the induced velocity would be calculated and the wake expanding radius determined on the basis of continuity equations of fluid flow,so that the divergence of the tip vortex radius was avoided and the amount of computation was reduced greatly.Through a typical example of wind turbine,the distribution pattern of axial induction factor computed by this method was more reasonable compared with the result obtained by the rigid wake model.This verified the correctness and practicability of this method which could provide an effective wake vortex calculation method for the aerodynamic design and performance calculation of horizontal-axis wind turbine rotors.