不同工作参数下水轴承的空化程度及微形貌特征对减阻效果的影响

目的为了提高水轴承高速下的减阻效果以及预测水轴承的空蚀区域,研究了高速水静压轴承的空化与减阻性能。方法基于低雷诺数Launder-Sharma模型和空化气泡的动力学模型,分析了不同工作参数下水轴承的空化程度研究及微形貌特征对减阻效果的影响。结果空化气泡主要出现在静压轴承水腔之间的负压封水面及小孔节流器附近,空化气泡溃灭时容易造成轴承材料的空蚀破坏。高速小偏心率时,相比流向和展向微形貌,凸柱微形貌特征表面具有较好的减阻效果,且减阻效果受轴颈线速度的影响较大。结论转速、供水压力和偏心率等物理参数影响水静压轴承空化气泡分布和静态性能,微形貌界面的速度滑移有利于提高减阻效果。

Influence of Cavitation and Microtopography of High-speed Water-lubricated Hydrostatic Bearing on Drag-reduction Effects

The woks aims to improve the drag reduction effects of water-lubricated hydrostatic bearing at high speed and predict the cavitation erosion area of the bearing by studying the cavitation and drag-reduction performance. A low-Re k-epsilon model allowing for cavitation was built based on Launder-Sharma Model and the Rayleigh-Plesset equation in order to analyze the influence of cavitation and microtopography of high-speed water-lubricated hydrostatic bearing on drag-reduction effects under different working parameters. Cavitation bubbles mainly appeared in vacuum water sealing suface between water cavities of hydrostatic bearing and near a restrictor orifice, which easily caused cavitation damage to bearing materials. At high speed and small eccentricity, compared with flow direction and spanwise microtopography, column-grooved microtopographic surface had better remarkable drag reduction effect among the three grooved surfaces, and the linear velocities of journal had significant influence on drag-reduction rate. Bearing parameters such as speed, supply pressure, eccentricity ratio can influence the distribution and static property of cavitation bubbles in water-lubricated hydrostatic bearing. In addition, obvious velocity slip contributes to improving drag reduction effect.