用于转子系统的气膜密封阻尼结构稳态特性

针对航空发动机转子既转动又进动的运转情况,推导用于转子系统的带金属橡胶弹性外环的气膜密封阻尼结构(gas film seal damper,GFSD)雷诺方程.基于GFSD运动方程和位移协调关系,建立转子－气膜－金属橡胶三者之间的流固耦合关系,确定稳态压力场求解流程,并提出金属橡胶刚度的定量设计方法.采用有限差分法求解稳态压力场,研究GFSD工作参数和结构参数对稳态特性的影响,为GFSD结构参数设计提供参考,最后与直通式篦齿封严的泄漏量进行比较.结果表明:合理设计金属橡胶刚度能够使GFSD自适应地调节气膜间隙;在保证动压润滑的基础上,选取大长径比、小金属橡胶刚度和密封间隙能够使GFSD具有良好的稳态特性;GFSD的泄漏量远小于直通式篦齿封严,能够满足现代航空发动机中高进出口压比下的封严需要. 

Steady-state properties of gas film seal damper used in a rotor system

In order to describe the movement of rotor system in an aero-engine that combines the rotation and procession together,the Reynolds equation of gas film seal damper (GFSD) was deducted.The fluid-solid coupling relationship among rotor,gas film and metal rubber ring was constructed based on the movement equation and displacement coordinated relationship,so the solution process of steady-state pressure field was clear and the design method for the stiffness of metal rubber was put forward.The finite difference method was employed to solve the steady-state pressure field,and the effects of working parameters and structural parameters on the steady-state properties were analyzed,which could provide references for the structural design of GFSD,and finally the mass flow-rate between GFSD and straight labyrinth seal was compared.The results show that the appropriate stiffness of metal rubber can make GFSD adjust the clearance of gas film adaptively.In order to maintain a dynamic lubrication condition,the larger the ratio of length and diameter,and the smaller the stiffness of metal rubber and clearance of gas film is,the better the steady-state properties are.The mass flow-ratio of GFSD is much less than that of straight labyrinth seal,and therefore GFSD could meet the requirements of the seals in advanced aero-engines.