薄膜润滑中双电层效应的理论分析与实验研究

建立了考虑双电层效应的有限宽组合滑块薄膜润滑数学模型,并利用组合滑块与圆盘的滑动摩擦试验对双电层效应进行研究,利用实验结果修正了润滑过程中双电层效应的计算,给出电粘度的计算公式并进行数值分析.结果表明:在薄膜厚度较薄的情况下,双电层效应使得流体的等效粘度随膜厚减小而迅速增加;随着膜厚增加,双电层的电粘度效应逐渐减弱;随着电场强度增加,双电层的电粘度效应增加,当电场强度达到一定程度时,双电层的电粘度效应开始减弱.

Theoretical Analysis and Experimental Study on Influence of Electric Double Layer on Thin Film Lubrication

A new mathematical model on the condition of thin film lubrication is established by taking into account the effect of electric double layer.In the present paper,experiments are carried out on a self-made tester.With a composite block and a sliding disk,influence of electric double layer on thin film lubrication is studied.Two different methods are used to reconstruct the field of electric double layer so as to change the effect of electric double layer.One is to change ionic concentration of lubricants by adding additives,and the other is to apply an external electric field on friction pair.According to theoretical analysis,both methods will apparently change electro-viscosity of the lubricant film so as to change the lubrication performances.After theoretical calculation of electro-viscosity is amended according to the experimental results,the equations of electro-viscosity are presented.The results show that equivalent viscosity of fluid induced by the effect of electric double layer apparently increases with decrease of thickness of the film while lubrication film is thin enough.Effect of electro-viscosity is weakened as thickness of the film increases.Moreover,effect of electro-viscosity increases with increase of external electric field at first.When value of voltage reaches a certain value,electro-viscosity begins to decrease.