Research On Contact Sealing Material And Performance For High Speed And High Temperature Rotary Shaft

In aircraft engines, sliding contact tribo-parts in typical tribo-elements (e.g. seals) often run with critical conditions tending to the material limitations, such as high speed, high temperature, low temperature and alternative high-low temperatures. Increases of wear often occur in the tribo-parts due to high contact pressure, intensified frictional heat and lubrication failure in aircraft engines that are trending for high thrust-weight ratio, high reliability and long life. Although materials and structures of seals has been gradually improved to meet requirements of aircraft engines, limitation of the materials has come in the applications in critical conditions. Therefore, researches on tribological performance of high speed and high temperature sliding contact tribo-materials are essential for theoretical and practical development of aircraft engine techniques. Enhance law and failure mechanism of composites under critical conditions can be revealed, severing well to design evaluation of new materials and design system of aerospace tribology.In the paper, sealing materials were designed under high speed and high temperature conditions combined with sealing medium of aircraft engines. Researches on wear behaviors of high speed and high temperature sealing composites in aircraft engines were carried out, the wear model of lip structure and leakage model were also established for seal performance and failure, providing theoretical basis to life prolonging and reliability growth of seals in aircraft engines.The matrix and fillers contents of composites,filled with CF, SG and FG, were adopted, basic performance and formed technique were tested. The tribologcial performances were tests by M-200test rig, and mechanic performances were tests by impact strength measurement，shore D hardness tester and tensile strength measurement. And components of composite was preliminary determinayed by tests. The temperature-controlling high-speed sliding contact test device, developed for investigating wear behaviors of composites, was designed according to parameters of limiting conditions in aircraft engines. The wear rate of PTFE composites with different sliding speed, temperture and fillers contents were tested by self-maded high-speed sliding contact test rig, results show that velocity, temperature and flake graphite has a significant influence on the wear rate.The worn surface and corss-section of composites were examed by SEM. Enhance law and failure mechanism of composites were also researched. Finding that CF can improved the intension and toughness of composites, as function of the skeleton stopping the matrix flow, SG decreased the friction coefficient of composites, FG improved the heat-conductiong properties and thermostabilities, the mechanical strength of composites decreased with FG added.Structure and contacted property under different lubrication condition during wear process were simulated by establishing a wear model based on Archard wear model and W-M wear model. Simulation results show that asymmetrical contacted pressure phenomenon diappeared with wear time running. Lubricated condition of high-speed lip seal steady operating period was fluid lubrication.Leakage rate and reverse pumping rate were analysed by establishing leakage model and reverse pumping model based on “pumping effect”. Experiment reseach at motor working condition was studied, it seemed fitted simulation well, and has none leakage during given running time.