Study On Dynamic Characteristics Of Thermal Hydrodynamic Lubrication Of High Speed Water Lubricated Spiral Groove Thrust Bearing Considering Cavitation Flow Multiple Interface Effects

The dynamic characteristics of the pumped water-lubricated spiral groove thrust bearing in the cavitation flow state are researched.Based on two-phase flow theory,the generalized Reynolds equation of cavitation flow is established,which considering the influence of multiple interface effects of gas and liquid at the laminar flow.According to the principle of conservation of particle number,the group equilibrium equationes is established,which describes the distribution of bubble volume.The source term of the micro-nucleus is considered at the high speed.The new model comparing to the single-phase mixed flow model can predict the distribution of bubble volume.The small disturbance method is used to deduce the perturbation pressure Reynolds equation of cavitation flow,and the calculation formula of stiffness and damping is given.The equations are dimensionlessly processed and the discrete is also completed.The SOR iterative method is a effective method to solve the generalized Reynolds equation,however,the N-SOR method to solve the nonlinear bubble population equilibrium equation is one of the methods.In order to expand the convergence scope,Newton's law of going downhill is one of the effective methods.The equations are coupled sovled in the boundary-fitting coordinate system,which is easy to mesh and convenient for programming using MATLAB.The program completes the numerical simulation of the equations.The results show that the experimental data of bubble probability distribution is consistent with the theoretical data,which indicates that the bubble volume equilibrium distribution model is reliable.And the theoretical data of the dynamic characteristics is in good agreement with the experimental results.The calculation results show that the population balance equation can be used to describe the evolution of bubbles size at the high speed conditions,the number of small-sized bubbles is larger than the number of large-sized bubbles.And bubbles are mainly distributed at the inlet and outlet of the spiral groove.The rotational speed and the structural parameters have a great influence on the stiffness and damping coefficients of the water-lubricated spiral groove bearing with cavitation flow.The cavitation effect causes that the direct stiffness coefficients of the cavitation are greater than the direct stiffness coefficient of the non-cavitation flow.The influence of cavitation effect for the damping coefficient is a little small.