Study On Static Characteristics Of Water-lubricated Hydrodynamic Textured Bearing Considering Cavitation Effect

Bearing as an important element in the rotation system,improve the bearing performance is critical for the whole system,this paper studies the texture effect on the properties of high speed water lubricated bearing,including radial bearing,spiral flute radial spiral groove bearing and thrust bearing,by changing the texture distribution in the bearing surface texture and texture shape size parameters on the influence law of bearing static characteristics.Due to the existence of texture,the initial cavitation number of lubrication fluid is high,and cavitation bubbles are easily generated in the high-speed lubrication state.At this time,the bearing is in the gas-liquid two-phase flow lubrication state.Based on the two-phase flow theory,a theoretical model of hydrodynamic lubrication for high speed water-lubricated cavitating bearings is established.The model includes the generalized Reynolds equation considering the gas-liquid interface effect and the population equilibrium equation describing the bubble state.The theoretical model is solved numerically.Due to both control equations for nonlinear equations in the model,so need through numerical iteration method,which USES over relaxation iteration solving the generalized Reynolds equation,the discrete time interval method and the step-by-step method to solve the bubble population balance equation,which can obtain texture of cavitation flow bearing pressure distribution and the bubble volume density distribution,and the static characteristics of the bearing.In order to verify the calculation results of the theoretical model,a high-speed waterlubricated bearing test bed was designed.The results are consistent with the experimental data,indicating the reliability of the theoretical model established in this paper.The numerical simulation results show that :(1)the probability density distribution of bubble volume is biased normal,and bubbles are concentrated in small volume region;The formation of bubbles occurs in the low pressure region where the water film diverges,and almost no bubbles exist in the high pressure region;The presence of texture leads to local pressure fluctuation and local low pressure intensifies cavitation;(2)Cavitation can increase bearing capacity,but has little effect on friction power consumption and flow;(3)The influence of texture on bearing performance depends on texture parameters such as shape,distribution and depth of texture and lubrication states such as speed and pressure;No matter which type of bearing,the presence of texture can reduce the friction power consumption of bearing,and the drag reduction effect becomes more obvious with the increase of texture area ratio and depth within a certain working range;(4)For radial bearings,the texture distribution in the liquid film convergence zone can significantly improve bearing capacity;For thrust spiral groove bearings,the influences of texture depth and area ratio on bearing capacity both increase first and then decrease,and there is an optimal value,and the optimal depth is affected by the film thickness.