Thermohydrodynamic Model of Cavitating Flow and Dynamic Characteristic Calculation for High-Speed Water-Lubricated Pump-Out Spiral Groove Bearing

摘要

A complete thermohydrodynamic lubrication model for pump-out spiral groove thrust bearings (SGTB) with cavitating flow is established based on two-phase flow and transport theory. Various effects (cavitating flow interface effect, convective heat transfer effect, heat conduction effect, inertia effect, breakage and coalescence of bubbles) of water lubricant at high speed are included when modeling. The bubble size distributions, bubble number density of the cavitating flow, and the dynamic coefficients of the SGTB are predicted using this model. The probability distribution of the bubble size, bubble number density, and axial film stiffness coefficient agree with the experimental values. The results show that the number of small-sized bubbles is much larger than the number of large-sized bubbles in cavitating flow. When the SGTB has a specified spiral angle, the direct stiffness coefficients increase and the cross-stiffness coefficients decrease due to the cavitation effect, but the influence of the cavitation effect on the damping coefficient is not obvious.