Research On Performance Of High-pressure Upstream Pumping Mechanical Seals

Upstream pumping mechanical seals have been widely used in industry with their non-contact end faces and zero leakage or zero overflows.However,due to the sealing face only micron film thickness,under various loads,the seal ring slight deformation and thermal deformation will have an important impact on the sealing performance.Further,the upstream pumping mechanical seal which suits in high-pressure are less,the pressure is hard to exceed 1.0MPa.Therefore,the research of the flow field,and temperature field and deformation for the high-pressure upstream pumping mechanical seals are significant.In this paper,the upstream pumping mechanical seal is selected as the object of study for the research on performance of mechanical seals based on simulation and experiment.The period model of fluid film and the period model of moving ring-stationary-fluid film for Fluent are constructed by Gambit.The flow and temperature fields of fluid film and the temperature distribution of rotating ring and static ring have been simulated.On this basis,the influence of speed,pressure and other conditions on the sealing performance has been analyzed.Further comparative analysis of the sealing performance for the seal end face with double row spiral groove or single row spiral groove has been done.For the end face with double row spiral groove,the influence of the angle of the spiral grooves on the sealing performance has been probed.Stress coupling,thermal coupling and stress-thermal coupling of the moving ring-stationary ring's deformation is computed by ANSYS Workbench.And the stress distribution with the effect of loads and constraints has been analyzed.It found that thermal deformation is much larger than the stress deformation,of the seal total deformation,it plays a major role.Also it is studied that the effect of changes in speed,pressure,temperature and other working parameters for stress coupling deformation,thermal coupling deformation and stress-thermal coupling deformation.Then the dotted line of the deformation with the changes of working parameters had been obtained.Based on the analysis for the deformation of the sealing face and the physical properties of the material used,the conclusion had been got that the seal faces should try to use the material with a high elastic modulus and low thermal expansion coefficient of the material.Finally,the performance test of the series connected upstream pumping mechanical seal had been done.It shows the pump seal test rig.A set of high-pressure upstream pumping mechanical seal and its corresponding test fixture had been designed.After a series of preparatory work with that the end surface grinding,over speed test and balancing test,the performance test for the upstream pumping mechanical seal had been done.By varying the pressure,speed and switching to the sealing rings with different groove,the experimental data had been respectively recorded.The experiment verified the numerical simulation results,and it signified that the designed upstream pumping mechanical seal could be applied to the 3.0MPa high pressure conditions.