Structure Performance Analysis Of High Speed Aerobearing And Its Experiment Research

The aerobearing is one kind of sliding bearing. The gas worked as the lubricating medium have the characteristics such as the viscosity changing little with the temperature, clean, resistant to radiation, and good compressibility. The aerobearing has merits such as low power consumption, long life period and high precision. However, the low viscosity and compressibility of the gas inhibits the application of the aerobearing in the reload areas. Aerobearing can’t improve the carrying capacity by increasing pressure of gas owing to the compressibility. Through the research, we can find that the increasing pressure of supply gas will cause congestion when gas get into film gap through inlet orifice, meanwhile the subsonic flow, supersonic flow, even the shock wave will happen in the gas film. The supersonic will lead to the pressure loss which is harmful to carrying capacity. To ensure the stability of high-speed rotor and the demanding for overload in special areas, the stability and bearing characteristics of aerobearing become the key problems. Aiming at aerobearing, this paper conduct the research on characteristics of the film flow, static characteristics of bearing, and the stability of high-speed rotor bearing system. The following work was carried out:1. According to the bearing structure and gas parameters, the gas model in the orifice and film and the calculation model were built. The hydrostatic flow field of aerobearing was analyzed. The flow field of gas film and orifice was established:first, the orifice model was built to judge whether the outlet congesting or not; second, the flowing pattern in the gas film was researched according to the gas parameters of orifice outlet and bearing structure; third, the subsonic and supersonic model were used to calculated flow field characteristics. The reasonable designing of hydrostatic aerobearing could be conducted through analyzing the relations of gas parameters, bearing structure, and the flow field in the gas film.2. Based on gas dynamic equation, continuity equation and gas state equation, the Reynolds equation of compressible gas could be derived. With the finite element method solving equation, using weighted residual method to discrete equations, the Reynolds equation in form of finite element equation could be get. The pressure distribution could be obtained through interpolation function, triangular unit, and iterative method. The carrying capacity, turbulent motion force, stiffness and damping of aerostatic bearing, hydrodynamic bearing with different were calculated type of groove, and hydro-hybrid bearing.3. The finite element model of bearing-rotor system was established, and the natural frequency was calculated. The influence of bearing, rotor to the natural frequency was studied. By analyzing the unbalance response at different rotating speed, the unbalance response was studied.The static and dynamic characteristics of aerobearing were experimented:first, the carrying capacity and stiffness were tested through static characteristic; second, based on the high-speed rotor bearing system and the nonlinear testing method, the dynamic characteristic experiments was conducted. The vibration characteristics of gas bearing-rotor system was tested, which can reflect the bearing performance. The low frequency eddy, the dual low-frequency vibration and low frequency oscillation of hydrostatic bearing; the effect of different groove line to rotor performance in hydrodynamic bearings; the characteristics of hydro-hybrid bearing were studied in the experiments.