断油时挤压油膜阻尼器的空气气穴流型及减振特性实验研究

Experimental study on flow visualization and damping characteristics of a squeeze film damper with air cavitation under oil cut-off condition

针对挤压油膜阻尼器在断油的工况下开展实验研究,考察阻尼器的气穴现象及其对阻尼器减振特性的影响,结果表明在供油压力较低的工况下,当轴径偏心率仅为0.13时时,阻尼器便从外界吸入空气到阻尼器油腔内,气液两相流的流型呈周期性变化,且多为非均相流;在气穴的影响下,阻尼器油腔内出现恒压区,油膜压力大幅减小;等效油膜阻尼系数呈周期性变化,阻尼效果减弱;阻尼器轴径偏心率越大,空气吸入量越大,阻尼器的油膜压力和等效阻尼系数越低。

The air cavitation phenomenon and damping characteristic of squeeze film dampers (SFDs) at different eccentric ratios are investigated experimentally under oil cut-off condition. The results show that much air is ingested into SFD oil chamber at a small eccentric ratio of 0.13, when the oil supply pressure is relatively small. The flow pattern of two-phase flow varies periodically, which is dominated by nonhomogeneous flow. Constant oil film pressure zones appear due to air cavitation and the oil film pressure drops dramatically. The equivalent oil film damping changes periodically with the flow pattern, and the SFD effectiveness weakens. More air is ingested into SFD oil chamber when the eccentric ratio increases, and the oil film pressure and equivalent damping become smaller.