The Research On Steady-state And Dynamical Characterization Of Hubricating Gaseous Film In The Sprial Grooved Gas Seals

The technology of dry gas seal comes from the developed industrial countries, and our products have relied on import for a long time.Our research on the dry gas seal technology and development of its product are just at the beginning stage.The whole system of design,development and manufacture of dry gas seal product has not yet been set up.Therefore carrying out its research has important significance for improving our level of dry gas seal technology.The paper takes spiral groove dry gas seal as research project,whose gaseous film flow and dynamical property are studied by theoretical calculation and experimental verification,and the influence as well as influence degree of the spiral groove's geometric parameters on the seal performance are analyzed,in order to find out optimized geometric parameters and obtain its optimum values.Based on the N-S equation and slip boundary condition,a nonlinear Reynolds equation for a steady-state and micro-scale flow field was derived.Using PH linearization,the nonlinear partial differential equation can be transformed into the linear partial differential equation,and then using complex function it can be transformed into two linear differential equation again.The problem was solved by using small parameter iterative method,and the approximate function expression of gas dynamic pressure in the spiral groove was obtained,and then the solution of flow velocity and spillage were found out,The calculating results in this paper agree well with the experimental one in the reference.It's useful for optimization design of gas seals about geometric parameters.Using multi-objective optimization method,a trade-off function of rigidity-to-spillage ratio was derived and optimized geometric parameters were acquired by solving the objective function under soft Maple programme.The given trade-off function of rigidity-to-spillage ratio was a nondimensional equation with universal adaptivity,so optimized geometric parameters under different process condition were obtained by solving it,which offers reliability theory foundation for optimization design of gas seals.Using PH linearization and variation method,A nonlinear Reynolds equation for a transient state and micro-scale flow field was solved,and the approximate function expressions of gaseous film rigidity on axial perturbation and angular eddy motion were derived.And then the steady-state boundary value problem for gaseous film was solved by using complex function and small parameter iterative method, and the approximate solutions of gaseous film rigidity were obtained.The best helix angles under different dielectric viscosity,pressure and rotating speed were acquired by analyzing the dynamic stability.The result shows that gaseous film rigidity will rise and its stability will be better when the pressure and rotating speed increase.The experimental investigation of a YTG-CTâ…¡type of groove dry gas seal was conducted on the 1800r/min high-speed centrifugal compressor test device in ChengDu YiTong Seal Co.,Ltd.The research finished overall plan of instrumentation system and hardware eonfignration,tested leakage,power lose and gaseous film rigidity,obtained test results and analyzed error between test and calculation data. Comparing some data from experiments with that of approximate calculation,the results show that dynamical and mathematical model of the gas flow between seal faces is validated correctly,and the developed program of approximate analysis method is practicable.