Wear Menchanism And Performance Optimization Of Mechanical Seal Of Rocket Engine Turbo Pump

Mechanical seal is a kind of sealing device widely used in rotating machinery,which has the adVantages of stable structurc and low leakage.In this paper,the liquid rocket engine turbo pump mechanical seal as the research object,aiming at the high parameter mechanical seal in the devclopmcnt process of low wear and high reliability requiremcnts,the wear mechanism and performance optimization research.The main contents are as follows:Firstly,the wear mechanism of mechanical seal of turbo pump is analyzed and the performance optimization scheme is proposed.In view of the problem of abnormal wear of mechanical scaI static ring of liquid rocket engine turbo pump in N2O4 environmental test,the causes of abnormal wear were analyzed,and two hypothetical models of resin corrosion and pore cavitation corrosion were put forward.The test results proved that the cause of the large wear of the static ring of the mechanical seal was the cavitation conosion caused by the fracture of the gas-phase N2O4 inside the pores of the graphite surface,which would make the graphite surface become loose and easy to produce large pieces of falling uff during contact friction.Secondly,in order to reduce static ring wear,mechanical seal structure improvement design and parameter optimization based on dynmnic and static pressure lubrication wer e carried out.The fluid film pressure distribution of mechanical seal was solved by finite difference method based on hydrodynamics control equation.Using the open furce and leakage as evaluation indexes,the performance of different groove seals was calculated and analyzed.Fluid simulation software was used to calculate the liquid film pressure of the combined groove at different rotating speeds.The influence of working condition parameters and structural parameters on sealing performanoe was calculated and analyzed by using sealing performance software.Based on orthogonal test method,a multi-objective groove shape parameter iptimization scheme was designed,and the optimal groove shape parameters were selected.Finally,the performance improvement of the graphite material of turoine pump mechanical seal static ring is studied,and the meclianical seal test platform is dcsigned.Based on the preparation technology of graphite,a scheme to improve the tribological properties of graphite by increasing the dipping pressure was put forward.In order to validate the performance of the optimized mechanical seal,using modular design method,design of mechanical seal test platform,could be divided into driver module,supporting module,test bench test modes of five modules,such as according to the characteristics of the mechanical seal to use and test requirements,determine the end face temperature,medium pressure and speed,leakage and the thickness of liquid film parameters,such as test plan.