接触角滞后与流体动压润滑的相关性研究

Correlation between Contact Angle Hysteresis and Hydrodynamic Lubrication

理论研究表明不同润湿性界面对流体动压润滑油膜厚度有着显著地影响,一般采用接触角(CA)来表征固液界面润湿性.而由热力学原理推导出的界面势能垒理论模型不仅与接触角相关,也是接触角滞后(CAH)的函数.本文作者通过对不同基体材料的滑块进行表面张力修饰,获得了不同亲和性的界面.利用干涉法及荧光法分别测量了不同润湿性界面的流体动压润滑膜厚及油膜受剪切的流动特性,研究了接触角及接触角滞后两个界面参数对流体动压润滑油膜厚度的影响,并对势能垒与接触角滞后的关系进行了讨论.结果表明:接触角与流体动压润滑油膜厚度的相关性较差,接触角滞后可以更好地表征界面效应对流体动压润滑油膜厚度的影响.

Theoretical studies have proved that different solid-liquid affinity surfaces have significant effects on hydrodynamic lubrication film.In general,contact angle(CA)is used to characterize the wettability of solid-liquid interface.However a theoretical model derived based on thermodynamic principles shows that the potential energy barrier of a surface is not only a function of contact angle,but also of another interfacial parameter,contact angle hysteresis(CAH).By modifying the surface of the slider,different affinity interfaces were obtained.The lubricating film thickness and the continuity of flow velocity were measured by a fixed-inclined slider bearing system using optical interference method and fluorescence method respectively.This study thus evaluated the two,CA and CAH,by conducting thin film hydrodynamic lubrication experiments with surfaces of hydrophilic and hydrophobic.Fundamental relation between the potential energy barrier and CAH was discussed.The results show that the correlation between CA and hydrodynamic lubrication oil film thickness was unsatisfactory.But CAH can better characterize the influence of interface effect on the hydrodynamic lubrication film thickness.