| Due to the elastic surface, compared to the traditional bearing,foil bearing has many advantages, and it has been applied to aviation, aerospace and other power machinery. But for a long time, the research of foil bearing was mainly focused on gas lubrication, and in some environments, oil must be the lubrication, the researches of foil bearing with oil lubricated is very necessary. Combined with the multi-leaf foil bearing and bump type foil bearing, this paper puts forward a new structure of foil bearing that is called multi-bump foil bearing. The analysis is mainly about the static and dynamic characteristics of oil lubricated multi-bump type foil bearing, and a test rig is built to measure the coefficients of the designed bearing, then the results are analyzed and compared with theoretical calculation.First of all, the physical model for oil lubricated multi-bump type foil bearing is built. The geometry structure of the designed bearing is analyzed, then the oil film thickness expression formula is established, and the Reynolds equation of the oil lubricated multi-bumo foil bearing is obtained, the finite difference method and relaxation iteration method was used to solve the Reynolds eq uation. By comparing the related literature the numerical method and the program is verified correct.Secondly, by solving the coupled foil deformation equation and Reynolds equation, the static characteristics of the multi-bump type foil bearing, the influences of the static characteristics with the speed, eccentricity, deviation angle, foil thickness are analyzed. Finally, the eight dynamic coefficients of the bearing are obtained by small perturbation method.Then according to the calculation, the eight dynamic coefficients of bearing are obtained and introduced to the bearing –rotor system. The actual model of the oil lubricatied multi-bump foil bearing- rotor system is established. Using the finite element method, the critical speed and unbalance respon se of the system are calculated, and the dynamic characteristics of the system are analyzed.Finally, the test rig of measuring the bearing dynamic parameters is designed, through the recognition algorithm of the measurement data the bearing dynamic coefficients are obtained, and compared with the theoretical calculations. |
