Research On The Influence Of Face Shape On The Main Pump Seal With Streamline Groove

In order to study the influence of the seal faces'shape on the performance of the nuclear main pump mechanical seal.This article takes the dynamic pressure mechanical seal of the nuclear main pump streamline groove as the research object.Based on the micro-element volume method and the average flow model analysis,a Reynolds equation mathematical model suitable for analyzing the dynamic pressure mechanical seal performance of the streamline groove considering the influence of the seal faces'shape is established.The geometric model of the streamline groove and the mathematical model of Reynolds equation considering the seal faces'shape are established.The finite difference method is used to solve and analyze.Use MATLAB to write calculation program.The effects of surface roughness,surface morphology parameters,liquid film thickness and working condition parameters on the opening force,leakage,liquid film stiffness and rigid-leakage ratio of the streamline groove dynamic pressure mechanical seal were studied,and the relevant laws were obtained.Provide a theoretical basis for in-depth analysis of the lubrication friction of the end face of the dynamic pressure seal of the nuclear main pump.The specific conclusions are:(1)The opening force,liquid film rigidity and rigid-leakage ratio of the streamline groove mechanical seal decrease with the increase of the liquid film thickness,and the leakage amount becomes larger with the increase of the liquid film thickness.Although the leakage increased,the leakage remained within a reasonable range,far less than 1.5m~3/h.In the area where the thickness of the liquid film is less than 4?m,the smaller the thickness of the liquid film,the greater the variation range of the opening force and the rigidity of the liquid film.(2)When the film thickness and surface morphology parameters are fixed,as the film thickness ratio increases,the opening force,leakage,liquid film stiffness,and rigid-leakage ratio of the mechanical seal of the streamline groove gradually decrease,and eventually tend to stable.When the film thickness ratio is less than 4,as the film thickness ratio increases,the opening force,leakage,liquid film stiffness and rigid-leakage ratio of the mechanical seal of the streamline groove are greatly reduced,which shows that a larger surface roughness will have a certain impact on the performance of mechanical seals.When the film thickness ratio is greater than 5,regardless of the sealing opening force,leakage,stiffness or rigid-leakage ratio,the influence law is basically the same,and the surface roughness has little effect on the performance of the mechanical seal of the streamline groove,and it can be ignored.(3)When the film thickness ratio is a fixed value,as the speed increases,the opening force,leakage,liquid film rigidity and rigid-leakage ratio become larger.As the rotation speed increases,the smaller the film thickness ratio(the greater the surface roughness),the greater the change in opening force,leakage,liquid film stiffness,and rigid-leakage ratio.(4)When the liquid film thickness is a fixed value,as the film thickness ratio increases,when the surface morphology parameter??1,the opening force,leakage,liquid film stiffness and rigid-leakage ratio are gradually reduced,and eventually tend to stabilize.When the surface morphology parameter?<1,the sealing performance parameter gradually increases,and eventually tends to be stable.In the area of film thickness ratio 1~4,the opening force,leakage amount,liquid film stiffness and rigid-leakage ratio of the mechanical seal of the streamline groove changed significantly.(5)When the film thickness ratio is a fixed value,the larger the surface morphology parameter,the opening force,leakage,liquid film rigidity and rigid-leakage ratio of the mechanical seal of the streamline groove will also increase.When the surface morphology parameter?>1,the mechanical seal of the streamline groove will have a good opening force,liquid film rigidity and rigid-leakage ratio,but it will also have a larger leakage.However,considering comprehensively,when the surface topography parameter?>1,the sealing performance is better,therefore,it is recommended to choose a sealing ring with surface topography parameter?>1.