Research On Contact Sealing Tecnology Of High Speed And High Temperature Rotary Shaft

With the rapid development of modern aerospace and space industry, working temperature and rotational speed of rotor system rises, as well as the press of the engine's system, which causes lubricate and seal hard in working conditions. Reliability and security of system are related with the technology of seal, it is necessary that researching on the structures and materials of seal for high-temperature and high-speed rotary shaft.Aimed at the demands of rigorous operational condition and compact structure, seal material adopt Polyetherimide(PEI)-based composite, and the structure of seal adopt lip seal structure. The additions of composites were designed, and tribological performance, mechanics performance, and microstructure of worn surface and cross-section of different addition contents were studied under room temperature, and the wear mechanism was also considered. Results show that filled with graphite or PTFE can also deduce the friction coefficient and reduce the wear, the transfer film is formed in worn process, so the friction coefficient is deduced and the wear rate is reduced.Considering von mises stress and deformation under different interference amount, module and seal press, the designed structure of lip seal was analyzed by FEM. Result show that interference amount shouldn't more than 0.15mm.Microstructure, mass loss and deformation of different addition content were studied in different temperature, and glass transition temperature of different addition content was also investigated. Results show that microstructure of graphite/PEI composites changes a little after 300℃, the mass loss changes within 0.27%, and the deformation changes within 2%. And microstructure of PTFE/PEI composites have a little cavities after 300℃,the mass loss changes within -0.08%, the deformation changes within 10%. When filled with more than 20wt.% graphite, the microstructure of graphite/PEI composites changes a little after 400℃, while others composites filled with less than 20wt.% graphite or filled with PTFE have some cavities. The mass loss of graphite/PEI composites changes within 1.1%, and PTFE/PEI composites is within 1.2%. The deformation of filled with more than 20wt.% graphite, is within 10%, is less than others composites filled with less than 20wt.% graphite or filled with PTFE, is within 40%. The glass transition temperature of PEI-based composite filled with graphite increases. While the glass transition temperature of composite filled with PTFE decreases.The high-speed wear tester was designed. The high-speed experiment under simulating operational conditions was performed, and wear mechanism was studied. Results show that the wear rate of PTFE/PEI composites is lower than graphite/PEI composites, and the main wear form of PEI composites is adherence wear.