Simulation Of Surface Roughness And Its Influence On The Properties Of Hydrodynamic Mechanical Seal

Compared with the conventional mechanical seal,the hydrodynamic mechanical seal has the advantages of low wear,high reliability and longer life.The clearance of hydrodynamic mechanical seal is usually only a few microns,and the film thickness is usually only one order of magnitude higher than that of the surface roughness,so the influence of the surface roughness on the flow field and sealing performance can not be ignored.However,the model of surface roughness and its influence on the performance of hydrodynamic mechanical seal are still in the process of exploration because of the extremely complex micro-scale flow in the clearance of hydrodynamic seal.Therefore,establishing a reasonable mechanical seal surface roughness model and analyzing the effects of surface roughness on the sealing performance can provide reference for the deep study of the mechanism of hydrodynamic mechanical seal lubrication and the design of seals.Under the support of the National Natural Science Foundation of China(project number:51279067),The simulation of the surface roughness of the mechanical seal and its influence on the hydrodynamic mechanical seal performance were studied,with the laser processing porous mechanical seal as the research object.The main research work and conclusions are as follows:1.Based on the basic theory of surface roughness,within the relevant standards range of mechanical seal,studies have shown that the surface roughness model of surface height accords with Gauss distribution,which can express the surface roughness of mechanical seal's end surface without losing loss.The random rough surface of mechanical seal is simulated by Matlab software,and the 3D coordinates of each point on the rough surface are obtained,the 3D model of liquid film water body is established by introducing UG software.2.The influence of surface roughness on hydrodynamic effects of hydrodynamic mechanical seal was simulated by Fluent software.The results show that in the range of parameters studied in this paper,when the pressure of the same medium is the same,the hydrodynamic effects of liquid film can be enhanced by considering the roughness of any part of the end surface of the seal ring,and the opening force is larger than thatof the smooth surface,and the greater the influence with the increase of the rotation speed.3.The effects of surface roughness on the properties of hydrodynamic mechanical seal was studied by respective considering the surface roughness of static ring,non micro-pores area of moving ring and micro-pores area of moving ring,and considering the surface roughness of 3 parts at the same time as an orthogonal experiment.The related experimental verification are also done.Studies have shown that,compared with smooth surface,the surface roughness of static ring,non micro-pores area of moving ring and micro-pores area of moving ring will increase the opening force and friction torque,and reduce the leakage.The experimental value of seal performance test is basically consistent with the simulated value,and the simulation results are proved to be reliable and correct within the limits of error.4.Based on the theory of hydrodynamic lubrication and the relationship between viscosity and temperature of sealing medium,the influence of surface roughness on the thermal properties of liquid film is studied when the depth of pores is 8 ?m and the temperature of sealing medium changes.The results show that the surface roughness can increase the temperature of liquid film compared with the smooth surface under the same working condition and different medium temperature,which has a negative effect on the heat dissipation of sealing gap liquid film.