Surface Texture Design And Multi-field Coipling Analysis Of Non-newtonian Fluid Face Seal

With the rapid development of modern industry,the requirements of mechanical seal performance,reliability and parts service life under extreme working conditions such as high speed,high temperature,high pressure and vacuum are more and more high.The direct contact of the seal ring will lead to the failure of the mechanical seal under extreme working conditions.The traditional mechanical seal can not meet the demand.The textured non-contact mechanical seal has become a new research direction.Grease,emulsion,crude oil,chemical raw materials and other commonly used fluids show non-Newtonian characteristics,widely used,these nonNewtonian fluid medium in the production and transportation process there are sealing leakage problems.The non-Newtonian characteristics of fluid medium will affect the sealing performance of mechanical seal,so the traditional analysis method of Newtonian fluid cannot be directly applied to non-Newtonian fluid.Therefore,in the study of mechanical seal,it is necessary to consider the non-Newtonian characteristics of fluid medium to better adapt to the actual conditions.In order to deeply understand the influence of non-Newtonian characteristics of fluid on the sealing performance and reveal the leakage suppression mechanism of textured mechanical seal,this paper takes the most widely used grease as the typical analysis object,and carries out research by combining theory and experiment.The main research contents and results are as follows:(1)Select grease as the non-Newtonian characteristics of fluid research object,obtain the rheological parameters of grease at different temperatures based on the rheological test,and fit the viscosity temperature equation of grease;The non-Newtonian characteristics of greases are analyzed from viscoelastic characteristics,flow characteristics and thixotropic characteristics.The results show that the grease has the characteristics of shear thinning and heat flux,and the fluidity can be effectively changed by increasing the shear rate or temperature.(2)Taking linear grooves with different inclination angles as the research object,the leakage numerical simulation of grease sealing pair was carried out considering the viscosion-temperature relationship of grease.Through the flow field distribution and fluid rheological characteristics,the mechanism of oblique groove suppressing leakage was revealed,and the influence law of different inclination Angle and speed on the clearance flow field of seal pair was obtained.The factors such as groove parameters and working conditions that significantly affect the leakage amount are systematically explored.The results show that increasing the groove inclination Angle can effectively reduce the leakage of the seal pair,and even reverse pumping occurs.Temperature and speed are the key factors affecting seal leakage,and the fluidity of grease is different under different working conditions.(3)The fluid-solid coupling model of the seal pair was established.Based on the flow field analysis,the multi-field coupling analysis was further carried out to explore the deformation law of the seal ring through different coupling ways.The results show that there are two kinds of sealing ring deformation: thermal deformation and elastic deformation.The direction of deformation is different,and the thermal deformation is larger than the elastic deformation.(4)Based on the theoretical research of textured mechanical seal,the mechanical seal test platform was built,the seal dynamic ring was prepared by laser processing method,and the seal test scheme was designed.The test results proved the correctness of the theoretical research in this paper.The research results obtained in this paper have important guiding significance for the texturization design of the end face of non-Newtonian fluid seal and the in-depth study of the coupling deformation of the seal ring,and can provide design basis and reference for the leakage control of the texturization seal pair of grease.At the same time,it can provide basic theoretical support for the texturization design to inhibit the leakage of nonNewtonian fluid.