Dynamics Study On Rotor-floating Ring Bearing System Of Micro-gas Turbine

In the fields of daily life, industrial production and military, micro gas turbine plays an important role that can't be ignored and has a broad space for development. Foreign developed countries attache great importance to the development of micro gas turbine. Owing to the advanced technology of floating ring bearing, the micro gas turbine has greatly enhanced energy efficiency and economic value. In view of the situation that our country has not yet fully mastered the core technology of floating ring bearing, we must launch a series of research for floating ring bearing as soon as possible so that our country can take a place in the field of advanced micro gas turbine.Based on the theory of hydrodynamic pressure lubrication of sliding bearing, this paper has deduced the Reynolds equation of floating bearing of inner and outer oil films, and then, studied of its dimensionless. Based on the DyRoBes software and finite difference method , this paper has analyzed the pressure of outer oil film by using the two ways, and got the change law of oil film pressure and floatring ring eccentricity under different speeds.By adopting the equivalent calculation method of stiffness and damping, this paper has discussed the changing of the stiffness and damping under different speeds. The stability of oil film was analyzed by using the method Routh-Hurwitz criterion. Based on the theory of Capone's cylinder bearing, the nonlinear oil film force model of floating ring bearing was deduced. Based on the dynamical equation of rotor-bearing system, this paper has deduced the dynamic equation of Jeffcot rigid rotor-floating ring bearing system. Following, this paper has studied the nonlinear dynamics characteristic of system with certain speed and certain rotor mass eccentricity.This paper has established the finite element model of the micro gas turbine rotor-floating ring bearing system. Based on the static and thermal-stress theories, the change law of radial deformation of floating ring was analyzed. Based on modal anslysis, the low-order natural frequency and vibration mode of the system under certain speed was obtained.