考虑变桨效应大型风力机塔架-叶片体系气动性能精细化分析

EFINEMENT ANALYSIS ON AERODYNAMIC PERFORMANCE OF LARGE WIND TURBINE SYSTEM CONSIDERING BLADE PITCH ANGLE EFFECT

以某5 MW风力机为研究对象,基于大涡模拟方法,考虑不同叶片桨距角大型风力机体系表面流场信息和气动力分布模式进行模拟,并与规范及实测结果进行对比验证大涡模拟的有效性。在此基础上,对比分析不同叶片桨距角下风力机塔架及叶片表面平均和脉动风压、升力与阻力系数、绕流及尾流特性的分布模式,总结叶片桨距角和干扰对风力机体系气动性能的影响规律。研究表明:随着叶片桨距角的增大,叶片迎风面正压分布区域逐渐减小,塔架显著干扰区段迎风面0°和侧风面90°处的平均风压、极值风压逐渐增大,而脉动风压逐渐减小,层升力系数减小,阻力系数增大。塔架未干扰区段平均风压、脉动风压、极值风压和层阻力系数均未呈现明显变化,在桨距角较大(70°~90°)时,叶片尾迹对塔架绕流影响逐渐减弱,塔架气动力分布与未受叶片变桨和干扰时较为接近。综合分析表明,叶片桨距角为0°时,叶片和塔架之间的相互干涉作用最为明显,风力机体系气动性能最为不利。

Taking a 5 MW wind turbine as the research object,large eddy simulation method was used to analyzed the of flow field and aerodynamic force of the large-scale wind turbine system by considering different blade pitch angles. The numerical simulation results were compared with code and measurement results to validate the effectiveness of large eddy simulation. On this basis,a comparative analysis of influences of blade pitch angle on average wind pressure,fluctuating wind pressure,lift coefficient,drag coefficient,flow-around,and wake characteristics on the surface of large-scale wind turbine system was carried out. The study found that:as blade pitch angle enlarges,the windward pressure distribution area on the windward side of the blade gradually decreases. On the significant interference zone of the tower,the average wind pressure and extreme pressure at 0° on the windward side and 90° on the crosswind side increases gradually and the fluctuating wind pressure gradually reduces,the layer lift coefficient decreases and the drag coefficient increases. On the towet’s non-interference zone,the mean wind pressure,pulsating wind pressure,extreme wind pressure and layer drag coefficient show no significant changes. When the pitch angle is relatively large(70°-90°),influence of blade wake on flowaround characteristics of significant tower interference zone is weakened,and aerodynamic force distribution is approximate to the non-interfered zone at the moment. Comprehensive analysis shows that under 0° blade pitch angle,the interaction between the blade and the tower is most obvious,and the aerodynamic performance of the wind turbine system is the most unfavorable.