Theoretical And Experimental Study On Thermo-hydrodynamic Lubrication Characteristics Of T-groove Gas Face Seals

With the application of T-groove gas face seal in high speed and high temperature field,the problem of high frequency perturbation and thermal effect caused by high speed operation of equipment becomes more and more serious.In order to master the dynamic characteristics of the T-groove gas face seal,this paper carried out theoretical and experimental research on the thermo-hydrodynamic lubrication characteristics of the T-groove gas face seal.Firstly,the geometric model of the T-groove gas face seal is established,and the external disturbance factor is considered.Based on the gas thermodynamic lubrication theory,the dynamic equation,the Reynolds equation,the energy equation,the heat conduction equation,the state equation,the film thickness equation,the interface equation and the viscosity equation are established.And the mathematical model of the theoretical analysis of the thermodynamic lubrication of the T-groove gas face seal is constructed,and the boundary conditions are set.Then,the steady-state characteristics of the T-groove gas face seal were analyzed,and the pressure distribution,temperature distribution and thermal deformation regularity were numerically calculated.The results show that under high speed and high pressure conditions,the temperature of the T-groove gas seal end face decreases along the direction of leakage,and the elastic deformation and thermal deformation of the end face form divergent deformation,resulting in the reduction of the gas film thickness.When the sealing pressure is 5 MPa,the gas film thickness decreases from 5 ?m to 1.62 ?m.Secondly,the dynamic characteristics of the T-groove gas face seal are analyzed,and the influence of the external disturbance frequency on the gas film stiffness,damping and amplitude is analyzed by using the small disturbance method.The results show that the external disturbance frequency produces additional pressure and temperature.When the disturbance frequency is 10000 Hz,the additional temperature caused by the gas film stiffness is 0.25 K,and the additional temperature caused by the gas film damping is 0.2 K.The gas film stiffness,the gas film damping and the axial amplitude are all affected by the disturbance frequency.Finally,an experimental study was carried out on the T-groove gas face seal,and the temperature distribution and leakage rate change rules of the end face under the conditions of different rotating speed,medium temperature and T-groove depth were measured experimentally.The results show that with the increase of the rotational speed,the temperature at the outer diameter of the end face is higher than the temperature at the inner diameter.When the rotational speed is 15000 rpm,and the medium temperature is 150?,the outer diameter is higher than the inner diameter of nearly 10?;as the medium temperature increases,the leakage rate decreases.When the temperature of the medium is increased by 75?,the leakage amount is reduced by 57%.The increase in the depth of the groove reduces the influence of the rotational speed and the medium temperature on the end face temperature.Through theoretical and experimental research,the temperature distribution and leakage rate change rule of T-groove gas face seal under high temperature and high speed conditions were obtained,which provided theoretical and experimental support for the engineering design of T-groove gas face seal,and had certain guiding significance for the prevention of seal failure.