压气机轴向扩压器叶片断裂分析

Fracture Analysis of Compressor Axial Diffuser Blade

为了确定航空发动机压气机轴向扩压器叶片断裂故障的断裂性质和产生原因,通过外观检查、断口分析、组织检查、硬度测试等手段进行初步检验,并从材料、设计、加工以及环境方面进行详细的故障分析。结果表明:轴向扩压器叶片断裂故障为高周疲劳断裂。在航空发动机工作状态下轴向扩压器发生共振,且在工作温度下轴向扩压器叶尖与后盖为过盈配合,此时叶尖与后盖发生刮摩,叶尖出现毛刺及划痕,在轴向扩压器叶片从靠近叶尖的共振节线处共振应力最大点的叶盆侧开始产生裂纹,最终发生高周疲劳断裂。建议增大轴向扩压器叶片厚度与前、后缘圆角和轴向扩压器叶片与后盖之间的配合间隙,以避免类似故障发生。

In order to determine the nature and cause of the axial diffuser blade fracture of an aeroengine compressor,the preliminary inspections were carried out through visual inspection,fracture analysis,microstructure inspection,hardness testing,etc.and detailed fail-ure analysis was carried out from the aspects of materials,design,processing,and environment.The results show that the fracture failure of the axial diffuser blade is a high cycle fatigue fracture.The axial diffuser resonates under engine working conditions,and its blade tip and the rear cover are in an interference fit under working temperature,causing the scraping of the blade tip and the rear cover and the occur-rence of burrs and scratches.Cracks initiate on the blade concave side of the axial diffuser from the maximum resonance stress point near the resonance nodal line of the blade tip and eventually lead to the high cycle fatigue fracture of the axial diffuser blade.To avoid the occur-rence of similar failures,it is recommended to increase the thickness of the axial diffuser blade and the fillet radii of the leading and trailing edges,and to increase the clearance between the axial diffuser blade and the rear cover.