Performance Analysis Of Foil Journal Aerodynamic Gas Bearing

Foil journal aerodynamic gas bearing uses gas as lubricant, its friction loss is very low. So it can be used in high speed rotation. The foil journal aerodynamic gas bearing has been widely used in military field, turbine expansion engine and other machines working on high rotating speed abroad, but in China, because it is difficult to study, and its complex structure and high production costs, this kind of bearing can not be applied in practice. So doing more research on the foil journal aerodynamic gas bearing's performance has great significance. In this papers, we do deeply research on the foil journal aerodynamic gas bearing's static characteristics, temperature field and dynamic characteristics based on the related theories of elastic mechanics, tribology and finite difference method. The conclusions of this paper can be used as theoretical foundation for future research.In this paper, we did the following jobs:1.We did deeply research on the foils'elastic deformation. Using the related theories of elastic mechanics, we got the cylindrical element's balance differential equations, deformation geometry equations and physical equations. Then we got the foils'deformation equation. The deformation of the foils can be used to calculate the bearing's static characteristics, temperature field and dynamic characteristics.2. Based on the hydrodynamic lubrication theory, we got the compressible fluids unsteady Reynolds equation. Then we solve the equation by finite difference method. At last, with the impact of the foils'deformation, we got the pressure distribution of the bearing's gas film and calculated its static characteristics. The static characteristics are the basic of the temperature field and dynamic characteristics research.3.Based on the energy equation, we built the bearing's temperature field model and solve it by finite difference method. At last, we got the temperature distribution of the bearing in workspace with the impact of temperature.4. Based on the concept of dynamic characteristics, we built the mathematical model of the bearing's damping and stiffness and solve the dynamic equation by finite difference method to got the bearing's dynamic stiffness and dynamic damped coefficient.