多重激励下C/C复合材料轴间指式密封泄漏与磨损机制及动特性研究

According to the character of aeroengine intershaft seal operating in high working parameters and exciting conditions,a new type C/C composite finger seal expected to be applied in intershaft is constructed in this project.The mechanism and performance of the new intershaft finger seal with floating sealing interface are analyzed by applying comprehensive method of theoretical analysis-numerical calculation-test research.Radial clearance flow in microscale conbined with circumferential gap permeation based on porous model analysis method is presented to analyze the leakage of intershaft finger seal.The prediction on the the complicated leakage performance and flowing in microcosmic and macroscopic characters with flow-solid-interaction is carried out. The influence and variation of seal flow effects of macro/micro dimension on sealing performance are presented.Based on the multi- lubrication model and composite material wear experiment,the hydrodynamic flow ,contact model and heat transfer are coupled and the frictional wear machanism is explored.The whole seal tribodynamic analysis model with two inputs and multi-direactional excitings is put forward. The dynamic analysis results of time-varying leakage and frictional thermal and the sealing force dynamic coefficients are calculated to evaluate the dynamic stability of roter-sealing system. By means of testing the leakage and dynamic parameters of the intersharft finger seal,the theoritical analysis model will be modified and verified. The framework and key method for study on the intershaft seal system with high performance and multi stimulus are formed ultimately.The work of this project would provide a new idea for exploring the theory and method of designing floating intershaft gas seal with high performance.It is significent in scientific method and engineering for improving the sealing technology of aeroengine ulteriorly.

针对航空发动机轴间密封高参数高机动运行特征，构建C/C复合材料轴间指式密封新结构，采用理论分析—仿真模拟—试验测试相结合的方式，研究浮动界面轴间指式密封的工作机理和性能特征。提出综合微尺度效应径向间隙流与多孔介质型周向缝隙渗流的指式密封泄漏流动分析方法，实现具有热流固耦合特征的复杂流道介质流动宏观与细观特征预测；基于多润滑状态分析及材料磨损试验，探求考虑表面形貌特征的密封介质流动、摩擦接触及能量传递的耦合效应及摩擦磨损机制；建立双轴输入及多向激励下轴间密封摩擦动力学分析模型，研究密封时变流量、脉动摩擦热及动特性系数等转子系统稳定性影响因素；通过不同激励下轴间密封动态性能测试，对理论分析模型加以验证和修正，最终形成多激励轴间密封系统性能研究的框架体系和核心技术方法。本项目为探索浮动界面新型气封的设计理论和方法提供了新思路和理论依据，继而对于提高航空发动机密封技术具有重要的科学意义和工程价值。

本项目针对航空发动机在高速旋转双转子之间进行气路密封的应用需求，在综合分析现有轴间密封特点以及指尖密封研究工作基础上，提出了一种新型的自适应柔性CC复合材料轴间指式密封结构形式。构建了C/C复合材料轴间指式密封的性能分析结构模型，采用理论-仿真-试验相结合的方法，分析了C/C复合材料的性能本构关系，研究了内伸式和外伸式轴间指式密封的力学性能特征。深入开展了CC复合材料指尖密封的泄漏和磨损性能分析，建立了指尖密封径向和周向泄漏流固耦合分析模型，提出了基于多孔介质的指尖密封周向缝隙泄漏分析方法；研究了压力闭合效应、热效应、转子转动离心效应、转子径向跳动等对指尖密封泄漏和接触磨损特性的影响；研究了轴间指式密封结构参数、材料参数、工况参数对密封性能的影响规律；开展了C/C复合材料与转子材料间的摩擦磨损性能试验，建立了C/C复合材料指尖密封磨损分析模型；提出的基于改进Archard磨损模型与自适应网格法相集成的C/C复合材料指尖密封磨损预测方法。开展了C/C复合材料轴间指式密封动态特性分析，分析了指尖密封/转子间的气膜间隙变化对指尖密封工作性能、对转子系统的动力学行为及其稳定性的影响；建立了考虑工作状态的指尖密封分布质量等效动力学模型，获得了转子倾斜、装配条件、冲击效应和温度效应耦合状态下指尖密封动态性能的变化规律。开展了C/C复合材料指尖密封泄漏和耐久性能试验，测试了密封的磨损性能，试验结果验证了理论分析方法的正确性。. 本项目通过对轴间指式密封内在科学问题的探究，形成轴间指式密封泄漏与磨损行为特征研究的理论方法和关键技术，为解决高自适应性、高参数轴间封严的设计难题提供了一种新思路。本项目对于探索柔性轴间密封系统流动效应及摩擦动力学行为的内在变化规律、提高航空发动机先进浮动式密封的设计水平和可靠性，具有重要的科学意义和工程价值。