连续凹槽基底对含非溶性活性剂薄液膜流动特性的影响  

Effect of periodic grooving topography on dynamics of Insoluble surfactant-laden thin film flow

作　　者：李春曦[1] 陈朋强 叶学民[1] 

机构地区：[1]华北电力大学,电站设备状态监测与控制教育部重点实验室,保定071003

出　　处：《物理学报》2014年第22期248-257,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10972077;11202079);中央高校基本科研业务费(批准号:13MS97)资助的课题~~

摘　　要：针对连续凹槽基底上含非溶性活性剂液膜的流动过程,采用润滑理论建立了液膜厚度和活性剂浓度演化模型,利用PDECOL程序数值模拟得到了液膜流动的动力学特征及基底结构参数的影响.研究表明:活性剂液膜流经连续凹槽时,负向台阶处形成凹陷,正向台阶处形成隆起,且随时间逐渐增大;与平整基底相比,连续凹槽下的活性剂液膜铺展速度加快;基底凹槽的高度增加或斜度减小可加速液膜破断的可能性;增大凹槽宽度可促进液膜流动;减小斜度会使液膜进入第一凹槽前形成隆起特征;重力在液膜的爬坡和下坡过程中具有相反的作用,但均使得流动稳定性变差;分子间作用力形成的结合压可加速液膜流动,进而引发去湿润现象,分离压则与之相反.Targeting the flowing of insoluble surfactant-laden film over topography substrate, the lubrication theory is adopted to derive the evolution equations of thin liquid film thickness and interfacial surfactant concentration. The flowing characteristics of the film on topography surfaces, and the influence of topography structure are examined based on the numerical simulation with PDECOL code. The results show that when the thin film of insoluble surfactant flows over periodic grooving topography, the depression appears at the negative step, while the ridge is shaped at the positive step, both of which increase gradually with time going by. Compared with the case of the flat base, the surfactant-laden film spreading speed is enhanced. Increasing the groove depth or reducing the groove steepness leads to the increase of the rupture possibility of the film. Improving the groove width promotes the film flowing. The decrease of the steepness can cause the film to form a ridge feature before entering into the first groove. Gravity has the opposite effects on the up-hilling and down-hilling processes of liquid film flow, which causes the flow stability to deteriorate. Conjoining pressure induced by intermolecular forces can accelerate the film, giving rise to a notable dewetting phenomenon, while disjoining pressure has an adverse effect.

关 键 词：活性剂液膜 非平整基底 铺展 分子间作用力 

分 类 号：O35[理学—流体力学]