Experimental Study Of The Effect Of Several Factors On Pumping Rate And Numerical Simulation Of Oil Seal

Oil seal is widely applied in all kinds of mechanical equipment.The sealing failure of oil seal has a serious effect on equipment and environment,so the reliable design of oil seal is particularly important.We can estimate whether the design of oil seal is qualified by experiment,but it is not only expensive but also inefficient,therefore,we can provide a direction for experiment and reduce the times and cost of experiment through numerical simulation.In this paper,experiment and numerical simulation are combined to study the dynamic sealing mechanism and heat generation heat dissipation of oil seal.In experimental section,the oil seal is installed on the oil seal testing machine reversely,then the pumping rate of oil seal is measured when several factors(interference,shaft speed,oil temperature,stiffness coefficient of spring and roughness of shaft surface)are changed.There are two parts in numerical simulation section.One is that the 2-D axis-symmetry model of oil seal used in experiment is developed using finite element method,then the contact stress distribution is simulated in different interference and stiffness coefficient of spring.The other is that the 2-D axis-symmetry model of oil seal used in experiment is built using CFD software,then the effect on oil film thickness and heat generation heat dissipation of oil seal is analyzed in different interference,shaft speed and oil temperature.The experiment results show that interference,shaft speed,oil temperature,stiffness coefficient of spring and roughness of shaft surface have a remarkable effect on pumping rate of oil seal.At a roughness of shaft surface of 0.2?m,the pumping rate drops with the increase of interference,stiffness coefficient of spring and oil temperature,while the pumping rate is enhanced with the increase of shaft speed.The effect of the four factors on pumping rate is from interference to stiffness coefficient of spring,oil temperature and shaft speed from big to small.The results of finite element simulation show that whether the spring is installed on oil seal or not and the variation of interference have a remarkable effect on the contact stress distribution of oil seal lip.The radial contact load,contact width and maximum contact stress increase with the increase of interference and stiffness coefficient of spring.The effect of pretension on the contact stress distribution of oil seal lip is greater than that of stiffness coefficient of spring.The results of CFD simulation show that the temperature on oil seal lip surface is higher than that on shaft surface within contact width,most of the heat generated by oil seal lip(more than 98%)is imported into shaft,then exported into environment by the heat convection between shaft and environment.The heat production rate of oil seal lip increases with the increase of shaft speed and interference and decreases with the increase of oil temperature.Oil film thickness positively correlates with shaft speed and negatively with oil temperature and interference.The pumping rate of oil seal can be calculated by substituting the gradient of contact stress of oil seal lip obtained by finite element analysis and oil film thickness obtained by CFD simulation into formula of pumping rate.There are some differences between calculated pumping rate and experimental data,but the variation trends of both are identical.