Study On Lubrication Characteristics And Sealing Performance Of High Speed Carbon Ring Seal For New Energy Vehicles

As the core component of rotating machinery equipment,the sealing device is related to the safe and stable operation of the equipment,but with the continuous development of fluid machinery to the direction of high parameters,the shaft end seals used in China are prone to leakage,wear and instability,and the service life is short,so it is urgent to introduce a better sealing technology to control the leakage of rotating mechanical seals.Focusing on the great demand of high-tech energy vehicles in our country,this paper makes an indepth study on the technical bottleneck of the high-speed shaft seal of the core parts of new energy vehicles,focusing on the steady-state sealing performance and prototype test.The lubrication characteristics of the micro-gap fluid film are deeply studied from two aspects of theoretical calculation and experimental research.The main work is as follows:On the basis of the study of laminar dynamic lubrication,this paper selects the compressible Reynolds lubrication equation based on Ng-Pan turbulence theory,which can be dynamically adapted to turbulent flow pattern and laminar flow pattern,simultaneous flow state criterion and flow field boundary conditions.The finite difference method is used to iteratively solve the medium fluid pressure control equation,and the distribution law of pressure and film thickness in the flow field of carbon ring seal is obtained.And the sealing performance is preliminarily analyzed and discussed,and the influence of operating parameters on the leakage characteristics of carbon ring seals with different shaft diameters under turbulence effect is studied.An oil-gas two-phase dynamic lubrication model considering turbulence effect is established.The finite difference method is used to discretize the theoretical model,and the overrelaxation iterative method is used to iteratively solve the pressure control Reynolds equation and the film thickness equation after the difference.The distribution of flow field pressure and film thickness is obtained,and the variation rules of flow field pressure and film thickness under different aspect ratio are compared.In addition,the effects of rotational speed,inlet pressure,oil-gas ratio,eccentricity and average film gap on the buoyancy and leakage rate of fluid membrane were analyzed.Finally,in order to verify the correctness of the relevant theoretical model established in this paper,the leakage rate test of the carbon ring seal prototype under different working conditions is carried out in this chapter,and the above theoretical calculation results are compared with the experimental test values.the error between the leakage measured by the test and the turbulence theory is the smallest,and the theoretical calculation model in this paper has a certain reliability.This study can lay a foundation for the optimization of carbon ring seal design,lubrication flow field performance analysis and engineering application in the future.