水污染作为润滑油污染的常见形式,对润滑油本身以及机械系统都有巨大的危害。为了模拟实际非均匀多相系统中的界面行为,本文搭建了高精度点接触实验台来研究传统的不溶相替换问题。将目前静态平行受限空间内油水界面行为的研究推广到动态点接触楔形受限空间内,探究了游离水滴穿过点接触狭缝间毛细油池过程中的界面特性。重点关注固壁润湿性以及固壁的分离运动对整个侵入过程中液滴动态行为的影响。实验发现了铺展系数是决定油水界面融合和分离特性的关键因素,揭示了固壁润湿性和球盘间的相对分离运动会影响游离水滴穿过毛细油池之后的粘附行为。表面张力和液体与壁面之间的粘附功能够解释观测的实验现象。
As a main source of lubricant contamination, water is one of the most important causes of failure and life reduction of lubricants and mechanical systems. To simulate the interfacial behaviors of real heterogeneous systems, a high-precision point contact experiment apparatus was constructed to study the classical immiscible displacement problem. The interfacial behaviors between water and oil, which are always carried out in the static and parallel space, have been extended to the dynamic point contact wedge in a confined space. The interfacial behaviors of water droplets invading the oil pool around the dynamic point contact region were investigated. Emphasis is placed on the influences of the wettability and the relative separation motion of the solid surfaces on the dynamic behaviors of the droplets. The spreading coefficient has been determined to be the key parameter influencing the coalescing and separating behaviors of the two-phase interface. The influence of the wettability of the solid surface and the relative separation between the ball and the disc on the final coalescing form has been determined. Surface tension and adhesion energy are used to interpret these observations