微型涡喷发动机离心叶轮掉块分析  

Fall-block Failure Analysis of Centrifugal Impeller of Micro Turbojet Engine

作　　者：陈光炯 方君 陆瑶 曾丽芳 陈世超 曾佑杰 CHEN Guangjiong;FANG Jun;LU Yao;ZENG Lifang;CHEN Shichao;ZENG Youjie(Hangzhou Huayi Technology,Hangzhou 310000,China;School of Aeronautics and Astronautics,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]杭州华翊科技有限公司,杭州310000 [2]浙江大学航空航天学院,杭州310027

出　　处：《失效分析与预防》2024年第6期456-460,共5页Failure Analysis and Prevention

基　　金：国防基础科研计划(JCKY2019205A006,JCKY2021205B003)。

摘　　要：微型涡喷发动机在地面试车过程中,在振动加速度基频和振动速度总量未超限情况下,出现峭度因子异常(远超正常值3)情况。停车分解后发现离心叶轮有一个叶片存在较大叶尖掉块,其余叶片在前缘不同位置存在较小缺口。对试车过程监测参数进行分析,明确叶片与离心机匣发生剐蹭;采用宏观检查分析方法,判断叶尖掉块为初始断裂;通过断口分析,确定叶尖掉块叶片为前缘起裂的高周疲劳断裂;结合离心叶轮共振转速以及振动应力分布的有限元分析,确定径向扩压器叶片激起的高阶振动为叶片断裂主要原因。通过改变离心叶轮材料、优化叶型以及增大根部倒角方式,最终改变叶片固有频率,增强叶片抗高周疲劳性能,排除此类故障。In the ground test process of a micro turbojet engine,the kurtosis factor appeared abnormal,far exceeding the normal value of 3,in the case that the fundamental frequency of vibration acceleration and the total vibration velocity did not exceed the limit.After stopping test and decomposition,it was found that one blade of the centrifugal impeller had a large fall-block at tip,and the other blades had small notches at different positions of the leading edge.The monitoring parameters during test was analyzed,and it was found that the blades had scraped with the centrifuge cartridge.Through macroscopic inspection,it is judged that the tip fall-block of the blade is initial fracture.Through fracture analysis,it is determined that the tip fall-block of the blade is high-cycle fatigue fracture caused by the leading edge cracking.Combined with the finite element analysis of the resonance speed and vibration stress distribution of the centrifugal impeller,it is determined that the high order vibration induced by the radial diffuser blade is the main cause of blade fracture.By changing the centrifugal impeller material,optimizing the blade profile and increasing the root chamfering,the inherent frequency of the blades can be changed and the anti-high cycle fatigue performance of the blades can be enhanced.As a result,such failure can be prevented.

关 键 词：离心叶轮 掉块 高周疲劳 高阶振动 

分 类 号：V232.4[航空宇航科学与技术—航空宇航推进理论与工程]