Research On The Performance Of Hydrostatic Bearing Of Large-type Ball Mill Based On Fluid-structure Interaction

With the advantages of high bearing capacity and long service life,hydrostatic bearing is widely applied to heavy mining equipment such as large-type ball mills. The failure of the hydrostatic bearing will result in the shutdown of the whole ball mill, and cause serious accidents and economic losses. Therefore, it is significant to study the flow fields of the hydrostatic bearing, the integrity of oil film and the static and dynamic stiffness.Based on the National Natural Science Foundation of China(NO.51265020),this thesis presents a simulation method in order to analyze and study the fluid-structure coupling of the heavy hydrostatic bearing with hollow shaft. The main contents are as follows:(1) This thesis created a simulation model on one-way fluid-structure coupling of the hydrostatic bearing of ball mill, analyzed the force performance of hydrostatic bearing under different working conditions, and obtained the working loads of hydrostatic bearing.(2) Based on the CFD simulation results of the hydrostatic bearing oil film and the FEM-contact model of the hydrostatic bearing, the one-way fluid-structure coupling of the hydrostatic bearing of ball mill is analyzed. In the thesis, the relevant laws on the stress distribution of the bearing bush and bearing seat, the contact status between the bearing bush and bearing seat, the stress and deformation distribution of rotary body is obtained. The results show that the maximum deformation between the two end faces of the hollow shaft is 0.2mm, which is close to the minimum oil film thickness.(3) The author develops a new simulation and analysis method for the two-way fluid-structure coupling of the hydrostatic bearing. After analyzing the thickness of oil film, the results show that the deformation of the hollow shaft and bearing bush has a great influence on the oil film thickness. In the position of the oil chamber, the oil film thickness is in a safe range. In the vicinity of the axial and circumferential resistive oil edges, the oil film thickness is in a more dangerous range.(4) In this part, the static stiffness of the oil film under different throttle modes is calculated. The results show that when the eccentricity of the hydrostatic bearing is small, its static stiffness is larger. The eccentricity should be less than 0.5 in the design of hydrostatic bearing. This thesis also uses the interference displacement method to analyze the dynamic stiffness coefficient of the oil film under the conditions of different loads, hollow shaft deflection angles and bearing clearances. The analysis results show that the changes of above-mentioned parameters have great influence on the dynamic stiffness coefficient of oil film.In this thesis, after simulating the fluid-structure interaction of the hydrostatic bearing in the large-type ball mill, the pressure, thickness distribution and stiffness of the oil film are obtained. The research results can be used as reference for the design of the hydrostatic bearing in large-type ball mill.