考虑离心力与热应力非连续界面的微动磨损

航空发动机、重型燃气轮机等旋转机械的组合转子轮盘间多采用非连续界面连接,通过建立两轮盘的环形平面接触有限元模型,并进行冷态预紧、升速工况下的结构分析及稳态温度场下的热-结构耦合分析。研究了环形接触界面的接触应力、切应力、磨损深度等微动参量的演变规律。结果表明:预紧力单独作用下接触应力从内径到外径逐渐减小,内径处接触应力和切应力最大,磨损最严重;随转速升高,离心力增大,接触界面的最大接触应力增大,最小接触应力减小,造成接触应力分布不均匀程度及磨损加剧;稳态温度场导致盘间接触应力均值大幅度上升,严重加剧轮盘间磨损;从盘间接触应力分布均匀性与界面微动磨损情况来说,热载荷是造成组合转子非连续界面微动磨损的主要因素。

Fretting wear of discontinuous interface considering centrifugal force and thermal stress

The disks of combined rotor of the rotating machines, such as aero-engine, heavy-duty gas turbine, are often joined by discontinuous interface, both structural analysis and thermal-structural coupling analysis were carried out for cold preloading and speedup stages as well as steady-state temperature field by establishing a two-wheel contact finite element model. The evolution of fretting parameters, including contact stress, the shear stress and fretting wear depth of the annular contact interface, was investigated. Results showed that the contact stress decreased gradually from the inner diameter to the outer diameter under the action of preloading force. The contact stress and shear stress were the largest at the inner diameter, and the fretting wear was the most serious. The maximum contact stress at the annular contact interface increased and the minimum contact stress decreased with the increase of the rotational speed and the centrifugal force, which caused the non-uniformity contact stress distribution and intensified the wear. The steady-state temperature field caused a large increase of the average contact stress, and it would seriously aggravate wear. Judging from the uniformity of the contact stress distribution and fretting wear condition, the thermal load is the main factor causing fretting wear on the discontinuous interface of combined rotor.