Study On Surface Texture Optimization And Active Control Of Fixed-Tilting Pads Combined Bearing

With the development of high-speed,high-precision,high-service performance of rotating machincry,etc.,the lubrication characteristics of the bearings and the operation stability of the bearing-rotor system has been widely concerned.Therefore,the research work of this paper mainly focuses on two aspects.Considering fixed-tilting pads combined bearing as the research object.On the one hand,the texture is processed on its surface and the texture parameters are optimized to improve the lubrication performance.On the other hand,the vibration control device is designed to improve the stability of the bearing-rotor system.The specific research includes the following aspects:1.The fixed-tilting pads combined bearing as the research object,and the Reynolds equation with spherical and cylindrical dimples texture is established.Based on the finite difference method,the oil film force is obtained,then the dimensionless bearing capacity and friction force are solved.On this basis,the effects of different texture shapes(spherical and cylindrical dimples texture),texture parameters(number,area ratio,maximum depth,etc.),texture position,etc.on the lubricating performance of the fixed-tilting pads combined bearing are analyzed.2.Establishing an optimized model for textured fixed-tilting pads combined bearing,with the maximum bearing capacity and the minimum friction force as optimization objectives,and by using the genetic algorithm to globally determine the distribution position and texture parameters of spherical dimples,the optimal combination of the distribution position and texture parameters under a given working condition is obtained.By comparing the bearing capacity and friction of the different textures(untextured,partial textured,and full textured)of the pads,the optimal texture is obtained.3.A model for solving the dynamic characteristics of the fixed-tilting pads combined is established,and the nonlinear dynamic behavior and stability of the combined bearing-rotor system are further analyzed.Based on the finite difference method,the oil film force is solved,and by using Runge-Kutta,the dynamic characteristics of the fixed-tilting pads combined bearing-rotor system is calculated.By using Poincare mapping,axis trajectory and time history,the dynamic response of the bearing-rotor system at different rotational speeds and different system parameters is analyzed.4.In order to further improve the stability of the fixed-tilting pads combined bearing-rotor system,based on active lubrication,the dynamic model of tilting pad bearing and Reynolds equation are established.By using finite difference method and Runge-Kutta method,the oil film force of actively lubricated tilting pad bearings is calculated.An electro-hydraulic control system based on PID control is designed,the dynamic response during PID control is analyzed and compared with the dynamics without active control.The above research provides a theoretical reference for surface texture design,optimization of texture parameters and stability in bearing-rotor systems for the fixed-tilting pads combined bearing.