涡轴发动机空中停车故障分析与验证

针对航空涡轴发动机在使用过程中发生的空中停车故障,通过对损伤件及其断口进行宏观和微观检查、金相组织观察、化学成分分析,以及损伤件的温度分析和磨痕对比,确定了首断件。结合发动机参数分析和质量复查,查明故障原因为发动机返厂检修重新装配时,前篦齿封严环与导流盘在规定的压紧螺母拧紧力矩下轴向压缩量偏小,在高转速状态出现轴向间隙,前篦齿封严环松动;前篦齿封严环与静子封严环径向间隙不均匀,切向摩擦力增大造成前篦齿封严环与导流盘相对转动而剧烈摩擦,局部温度升高,导流盘破裂,导致发动机空中停车。通过计算和螺母拧紧力矩试验进一步研究了故障机理,并针对故障机理开展部件和整机模拟试验,复现了故障现象。

Analysis and Verification of Turboshaft Engine Air Parking Fault

Aiming at the air parking failure of aero-turboshaft engine in service,the first fracture was determined by macroscopic and microscopic examination,metallographic observation,chemical composition analysis,temperature analysis and wear marks comparison of the damaged parts. Based on the analysis of engine parameters and quality review,it was found that the failure reason was that when the engine was repaired and reassembled,the axial compression of the front labyrinth sealing ring and guide plate was small under the tightening torque of the prescribed tightening nut,the axial clearance occured at high speed,the front labyrinth sealing ring was loosened. The radial clearance between the front grate sealing ring and the static sealing ring was uneven,and the increase of tangential friction caused the relative rotation of the front labyrinth sealing ring and the guide plate,resulting in severe friction between the front labyrinth sealing ring and the guide plate,the increase of local temperature and the rupture of the guide plate,which leads to the engine air parking. The fault mechanism was further studied by calculation and nut tightening torque test. The simulation test of components and the whole machine was carried out according to the fault mechanism,and the fault phenomenon was repeated.