叶尖开孔对风力机流场的影响研究

以NREL Phase VI叶片的1/8缩比模型为研究对象,在叶片叶尖区域设计由前缘到叶尖端面的3个环形通气孔,改变叶尖流场分布.采用CFD的方法,通过转速变化分析叶尖表面的压力分布情况及其叶尖涡的发展过程,进而研究叶尖开孔对风力机叶尖涡的影响.研究结果表明:转速低于900 r/min时,叶尖开孔对叶片气动性能影响不大;而转速高于900 r/min时,叶尖开孔可降低涡核强度,加速叶尖涡耗散,提高叶片气动效率.从环形通气孔中喷射的气流对来流有明显的抑制作用,能够减小尾流区内的轴向速度.在加速叶尖涡的耗散和降低叶尖涡的强度方面,风力机叶尖处开孔在转速超过900 r/min以上时被视为一种比较有效的设计.

Study on effect of blade tip slot on blade tipflow field of the wind turbine

Taking the 1/8 scaled model of the NREL Phase VI blade as the research object, three annular slots from the leading edge to the tip surface of the blade are designed in the blade tip region to change the distribution of the blade tip flow field. Using the CFD method, the pressure distribution on the blade tip surface and the development process of the tip vortex are analyzed through the speed change, and the influence of the blade tip slot on the tip vortex of the wind turbine is studied. The research results show that when the speed is lower than 900 r/min, the blade tip slot has little effect on the aerodynamic performance of the blade. When the speed is higher than 900 r/min, the blade tip slot can reduce the strength of the vortex core, accelerate the tip vortex dissipation, and increase the aerodynamic efficiency of the blade. The air flow jetted from the annular slots has a significant blocking effect on the incoming flow, and can reduce the axial velocity in the wake region. In terms of accelerating the dissipation of the tip vortex and reducing the strength of the tip vortex, the slot at the blade tip of the wind turbine is considered to be an effective design when the speed is higher than 900 r/min.