Theoretical And Experimental Study On Liquid Lubricated End Face Seals With Directional Microporous

The directionality of surface patterns can guide the fluid flow in the seal gap, lead to fluid cumulative effect along the dimples’inclined direction, cause obvious hydrodynamic effect, reduce the seal leakage, friction and wear. Theoretical and experimental research on seal performance of mechanical seals with directional microporous with different arrangement and shapes was carried out in this paper to improve the weak hydrodynamic effect of circle style micropors in low speed or high pressure.Firstly, taking the cavitation of liquid film between the two faces into consideration, a mathematical model of directional ellipse microporous liquid lubricated mechanical seal was proposed based on the fluid lubrication theory and JFO cavitation boundary condition. The structure parameters and seal performance parameters were defined. The method to calculate the surface film pressure field was researched. The validation of the computational program was verified to ensure the correctness of the theoretical simulation and calculation method.Secondly, under different operation parameters and different geometric structure parameters, the research was made on seal performance of liquid-lubricated mechanical seals with the different arrangements and shapes of directional microporous based on the theoretical model and the calculation method. The mechanism of directional dimples producing high hydrodynamic effect and low leakage rate was investigated. The optimal micorpous structure parameters were obtained. The results showed that directional dimples display better hydrodynamic effect and lower the leakage rate than the circle style microporous in the same operating condition. The rectangle micoporous have the best hydrodynamic effect. The diamond microporous show smaller leakage rate. The ellipse micoporous have the best comprehensive properties.Finally, a new type of mechanical seal was invented to solve the failure problem of mechanical seal of Catalyst pump in LanZhou Petrochemical Company. One of the seal end face was etched with double directional microporous. The springs are mounted outside of the seal chamber. The new seal structure was tested in indoor and field under the different spring pressure, different face shapes, and the sealing medium with solid particles. The results showed that the mechanical seal displays low friction torque, low temperature and low wear. The new seal structure can ensure the long period operation of catalyst pump.The research work is helpful in perfecting design theory of laser textured porous seal and provide effective theoretical guidance for the design of mechanical seal for pump with high solid content liquids, and which has a strong value for engineering.