运行状态下风力机叶片涂层沙蚀磨损研究

Research on Sand Erosion Wear of Wind Turbine Blade Coating in Operation State

通过对运行状态下的1.5 MW风力机叶片缩微模型进行冲蚀磨损试验,模拟真实运行状态下风力机叶片涂层的冲蚀磨损过程,研究不同叶轮转速、叶片分区、沙粒粒径对叶片涂层冲蚀磨损量的影响,分析叶尖前缘和近后缘处表面磨损的微观形貌,明确了运行状态下风力机叶片与沙粒之间的相互作用方式及冲蚀磨损机理。运行状态下,风力机叶片涂层冲蚀磨损进程特征依次为麻面、冲蚀坑、冲蚀坑合并、涂层小块剥落和涂层大面积剥落。不同叶轮转速下叶片涂层的冲蚀磨损量虽存在差异,但冲蚀磨损进程有着较高的相似性,可将整个过程分为磨损孕育期、快速磨损期和缓慢磨损期。随着冲蚀区域与叶根距离的增大,叶片涂层的冲蚀磨损量不断增大。不同粒径沙粒冲击叶片涂层,冲蚀磨损进程总体趋势相似,但粒径越小,冲蚀磨损进程的发展越缓慢。沙粒冲蚀前缘处的相对运动可近似为垂直冲击,冲蚀磨损特征主要为近圆形冲蚀坑及横向裂纹扩展下的涂层脱落;冲击近后缘处时,冲蚀磨损程度明显低于前缘处,冲蚀磨损形式主要为凹形压痕及鳞片状薄片脱落。

The erosion process of wind turbine blade coating in real operation state was simulated,based on the erosion wear test of 1.5 MW wind tur⁃bine blade miniature model in operation state.The interaction mode and erosion mechanism between wind turbine blade and sand particles under running state were clarified,by studying the influence of different impeller speeds,blade zones and sand particle sizes on the erosion amount of blade coating,analyzing the micro⁃morphology of surface at the leading edge and near the trailing edge of the blade tip.In operation state,the erosion process of the wind turbine blade coating was characterized by surface voids,erosive pits,erosive pits combined,small coating peeling and large coating peeling.The erosion process has high similarity,although the erosion amount of blade coating under different impeller speed is not same,the whole process can be divided into wear gestation period,fast wear period and slow wear period.And the erosion amount of the blade coating increases continuously,as the distance between the erosion zones and the blade root increasing.The general trend of erosion process is similar when different size sand particles impact blade coating,but the smaller the particle size,the slower the erosion process develops.The relative motion of sand erosion leading edge can be approximately vertical impact,and the erosion characteristics are mainly near circular erosive pits and coating peeling under transverse crack propagation.The erosion degree is lower than that of the leading edge when the impact is near the trailing edge,and the erosion forms are mainly concave indentation and scaly flake off.