基于偏斜变形下航空发动机浮动密封激振失稳的机理研究与定量识别

针对航空飞机变姿态运行诱发浮动密封激振失稳与泄漏已成为发展高参数航空发动机的瓶颈问题。本项目基于浮动密封偏斜下的运动轨迹，充分考虑高速重载变温工况引起的浮环气膜热流固变形规律，构建气膜-密封环-柔性支撑组成的非线性动力学数值模型，从而采用高精度交替方向隐式差分法与多重网格法，获取浮环密封膜压成形规律和静动态特性参数；其次，利用Treanor积分与Lyapunov指数，开展偏斜变形过程中气膜-转子激振力诱导浮动密封非线性不平衡动力响应研究，探明密封失稳的形成模式、演变规律与多重影响机理；随后，对浮动密封在偏斜变形下的失稳参数域范围进行定量识别；最终，结合浮动密封多姿态变激振的专用试验台架进行测试分析与理论模型验证，掌握航空发动机浮动密封振动失稳的信息传递规律，为提高航空发动机服役寿命奠定理论基础。

It has become a bottleneck problem for the development of high-parameter aeroengines for the instability and leakage of floating seals induced by aeroplanes. Based on the trajectory of the floating seal deflection, this project fully considers the thermal fluid-solid deformation law of the floating ring film caused by the high-speed heavy-duty variable temperature working condition, and constructs the nonlinear dynamic numerical model composed of the gas film-seal ring-flexible support. The high-precision alternating direction implicit difference method and multi-grid method are used to obtain the pressure forming law and static and dynamic characteristic parameters of the floating ring sealing film. Secondly, using the Treanor integral and the Lyapunov exponent to carry out the film-rotor excitation during the skew deformation process. Force-induced nonlinear unbalanced dynamic response of floating seals, probing the formation mode, evolution law and multiple influence mechanism of seal instability; then, quantitatively identifying the range of instability parameters of floating seals under skew deformation; Combined with the special test rig of floating seal multi-attitude and variable vibration, the test analysis and theoretical model verification are carried out, and the information transmission law of aero-engine floating seal vibration instability is mastered, which lays a theoretical foundation for improving the service life of aero-engine.