风机叶片涂层雨蚀研究

研究了风电叶片在雨水冲击下的失效过程,利用有限元方法建立雨水冲击的数值模型,分析了雨滴的冲击角度、直径、涂层性能等对涂层受力的影响,并对双雨滴及四雨滴耦合模型进行了研究。结果表明:风雨耦合流场中叶片最大载荷在叶尖处,涂层的冲击受力与雨滴冲击角度和雨滴直径的大小呈正相关。低模量涂层能大幅降低涂层受冲击时的拉伸应力,小幅增加其压缩应力。同一平面内的双雨滴耦合时,拉伸应力受影响的范围较大,压缩应力受影响的范围较小。不同高度差下的双雨滴耦合中,随着高度差的增大,材料拉伸和压缩应力都呈现先增后减的趋势,其中压缩应力随高度差的变化幅度明显大于拉伸应力。四雨滴耦合时压缩应力对间距的变化更加敏感。涂层失效的过程主要为:涂层表面拉应力疲劳产生微裂纹;液压渗透引起裂纹扩展,涂层质量减少,表面粗糙度增加;表面小范围破坏后形成的凹面结构促进涂层的失效。

Research on wind erosion of wind turbine blades

In order to obtain the effect of rain load on the coating of wind turbine blades,the wind turbine blades under rain load is studied and the rain erosion effect is investigated.The wind field and raindrop are regarded as continuous phase and discrete phase,respectively.The fluid dynamics finite element method is used to simulate the rainwater impact process,and the impact force distribution of the rain load on the blade surface is obtained.Finally,the impact process of the single raindrop on the blade is numerically simulated,and the coating partial force during the impact process is obtained.The results show that the maximum load of the blade in the wind-rain coupled flow field is 5.63kPa at the tip of the blade,and the velocity in this position is 95.9m/s.When the diameter of the raindrop reaches 6mm,the maximum deformation in the Z direction is 1.39mm,the maximum compressive stress is 4.244MPa,and the maximum tensile stress in the X and Y directions is 28.921MPa.In the double raindrop coupling effect,the stress changes in the Z direction at different intervals are small,but the tensile stress in the X and Y directions increases as the distance between the raindrops decreases,which increases the stress fatigue of the coating material,results in the appearance of microcracks in the surface of the material.