凹槽基底上含不溶性活性剂液膜的流动特性

针对凹槽基底上含不溶性活性剂液膜的流动过程,采用润滑理论建立液膜厚度和浓度演化模型,通过数值模拟得到液膜的流动特性及相关参数的影响规律.研究表明:含不溶性活性剂液膜在凹槽基底上流动时,重力和活性剂浓度梯度引起的Marangoni力对液膜的流动起促进作用,表面活性剂通过引起表层液体流动进而牵引内部液体运动,但其作用力相对重力较弱,重力起主导作用;与基底尺寸有关的粘性力则起阻碍作用;提高邦德数G和减小毛细力数C具有减弱液膜变形的作用;增大凹槽高度或减小凹槽斜度,均使Marangoni力增加,促使液膜变形加大.

Flow of Thin Film Containing Insoluble Surfactant over Grooving Topography Surface

For flowing of thin film containing insoluble surfactant over grooving substrate, lubrication theory is adopted for evolution equations of liquid film thickness and interfacial surfactant concentration. Film flowing characteristics and the effects of related parameters are numerically simulated. It shows that as thin film of insoluble surfactant flowing over grooving topography, gravity and Marangoni stress driven by surfactant promotes flow of liquid film. Gravity plays a leading role since influence of surfactant is limited by fl ows of surface liquid and adjacent bulk liquid. Viscous force associated with topography has an opposite effect. Film deformation is weak as improving Bond number or reducing capillary number. Increasing groove depth or decreasing groove steepness encourages film deformation as improving Marangoni stress.