Research On The Lubrication Performance Of Lip Seal And The Influences On The Rotor Dynamics Performance

The sealing performance of lip seal, which is an important element of machinery, is directly related to the service behavior and service life of machinery. With shaft rotating, a lubricant film between the seal and the shaft will be generated to ensure proper sealing. In the past, the random microscopic topography of both lip seal and shaft surface was not considered in most researches on hydrodynamic lubrication of lip seal. The initial elastic deformation and the randomly varied topography of lip surface when working were usually ignored in most hydrodynamic analysis. The relationship between different interference of sealing lip and lubrication and sealing performance were not studied in previous numerical researches. Moreover, the action of lip seal on the vibration performance of rotor system was not studied yet. According to above disadvantages, numerical simulation and experimental research are both carried out to study the lubrication and sealing performance of lip seal, as well as the influences of lip seal on the vibration performance of rotor system.The research and achievement of this dissertation include following aspects. The index autocorrelation function of rough surface is constructed by applying two-dimensional digital filtering technology based on AR model and computer simulation method of rough surface based on random process and time series model, the3D topography of sealing lip and shaft surface are simulated. The FEA model of the interference contact between sealing lip and shaft is established to calculate the radial deformation coefficient matrix and circumferential deformation coefficient matrix of lip seal. A numerical simulation method is proposed, in which the topography of sealing lip and shaft surface, the interference and elastic deformation of sealing lip are all considered. The numerical simulation research is conducted on the lip seal, the relation between lubrication performance and initial interference are analyzed. A numerical simulation method on leakage rate of lip seal is constructed with considering such aspect as interference, sealed pressure and flow fluctuation of each section on width direction of sealing zone. The method of analyzing the influence of shaft eccentricity on sealing performance of lip seal is established, and the sealing performance of lip seal with different interference, different sealed pressure and different shaft eccentricity is studied. A numerical simulation method on the thermoelastohydrodynamic radial lip seal behavior is proposed by applying Reynolds equation and "Global heat balance", in which the topography of sealing lip and shaft surface, interference, contact position, contact angle and contact width are considered. The relationship between rotation speed, interference and such lubrication parameters as film thickness, film pressure, friction force, heat dissipation, temperature, leakage rate is calculated and studied. The dynamic model of bearing-rotor-sealing system is established by applying transfer matrix method. The natural frequency, attenuation coefficients and modal shape of bearing-rotor-sealing system’s vibration are calculated and analyzed, as well as the influences of eccentric of impeller and belt wheel on the unbalance response amplitude of the system. The effect of lip seal on the vibration performance of the system is studied by the comparison between bearing-rotor-sealing system and bearing-rotor system. The relation between interference and temperature increment of sealing system, friction force of sealing zone are also studied by experiment. Through the comparison of numerical calculation results and experimental results, the reliability of numerical simulation done in this dissertation is certified to some extent.The research and achievement of this dissertation can provide important theoretical foundation for the further study on lip seal performance and its application in industry.