前曲扭角增加式叶尖气动特性研究

RESEARCH ON BLADE’S AERODYNAMIC CHARACTERISTICS WITH FORWARD CURVED AND INCREASED TWISTING TIP

以某150 kW水平轴的风电机组叶片为研究对象,提出一种朝来流风方向圆弧式前曲、扭角增加的降载叶尖外形;建立以扭角增量A、弯曲角度B为变量的16组叶尖几何模型,为探究该降载设计叶片最佳适用风况,建立考虑扭角增量、弯曲角度及风速的三因素四水平正交试验表,借助ICEM完成多组仿真模型的网格划分,利用Fluent单一旋转坐标系法对叶片进行流场分析,获得各组模型的转矩、推力等参数,采用因子效应对风速、弯曲角度、扭角增量进行评估。结果表明,在接近约9 m/s风速时,叶尖扭角增量为10°,弯曲角度为30°的前曲增扭叶片具有最优的降载特性,相较于初始叶片,在保证功率基本不损失的情况下,轴向推力减少约6.5%。

Based on a certain 150 kW variable-speed variable pitch blade,a blade tip profile with arc-shaped forward bending in the direction of the incoming wind and increased torsion angle is proposed to reduce load.The influences of torsion angle increment,bending angle and wind speed on the aerodynamic characteristics of the blade are comprehensively considered,thus a 4×4×4 group of orthogonal experimental geometry models are established.After that,the flow field analysis is completed by the Fluent rotating coordinate system method,with which the parameters such as moment and thrust of each group are obtained.Comparing the simulation results of 16 sets of models,the factor effects are used to evaluate the influence of wind speed,bending angle and torsion angle increment on the aerodynamic characteristics of the blade.The main conclusions are as follows:the proposed tip shape has no obvious effect on the blade’s aerodynamic characteristics at wind speed that is far below or above the rated wind speed.Under the rated wind speed of 9 m/s,the blade tip with 10°torsion angle increment and 30°bending angle has the best load reduction characteristics compared with the initial blade,and the axial thrust is reduced by about 6.5%without power loss.