Sealing Performance Analysis Of Packing Based On Mixed Lubrication Theory

Packing seal is a key component in the process equipment of petroleum,machinery,chemical industry and other industrial production fields,which plays a role in inhibiting the leakage of high pressure,high temperature and toxic media inside the equipment.The sealing performance analysis is of great significance to ensure the safety and long-term operation of the equipment.In this paper,the Y_X-shaped forming packing seal of reciprocating shaft was used as the research object,and numerical simulation analysis of sealing performance was conducted.The main research contents are as follows:Based on the theory of mixed lubrication,the mathematical model of sealing performance analysis of the molding packing seal was established which couples the hydrodynamics problems in the contact area,the elastic contact problems between rough peaks on the sealing contact surface and the problem of deformation mechanics.The FVM and FEM numerical computation scheme of Reynolds equation considering cavitation and roughness in hydrodynamic problems are derived.Python programming and commercial finite element software Comsol Multiphysics are used to solve the Reynolds equations respectively.The results of the two numerical methods are compared.The accuracy and validity of the computational method are verified.The static finite element analysis model of Yx-shaped seal was established by Ansys Mechanical.The influence of mechanical properties of materials on sealing performance was studied in view of the current situation that sealing design departments always design seals made of different materials based on the same standard.The influences of medium pressure and machining deviation on the static seal performance were analyzed,and the main geometric parameters affecting the static seal performance were found by orthogonal test and sensitivity analysis.The mixed lubrication numerical model was used to simulate and analyze the dynamic sealing performance of Y_Xshaped seal,and the variation of state parameters such as medium film thickness,the contact pressure between rough peaks and the fluid pressure with medium pressure,reciprocating speed and comprehensive roughness of sealing system was analyzed.On this basis,the variation law and mechanism of sealing performance parameters(friction force and leakage rate)with working condition parameters and surface morphology parameters are studied.The response surface optimization model of key structural parameters on seal leakage rate and external stroke friction was established to optimize the geometrical parameters of Y_Xseal,which improved the lubrication of seal,reduced the friction heat in the process of seal operation,and ensured the long-term operation of seal system.Based on the mixed lubrication model and coupled with the wear model,the wear problem of the molding packing seal was analyzed.The variation of state parameters such as wear rate,wear trace morphology,lubrication state and leakage rate with running time and the influence of operating parameters on seal’s wear behavior are studied.On this basis,the corresponding operation suggestions are given.