毛细管出口表面活化剂包覆液滴形成过程研究 1)

DROP FORMATION FROM A CAPILLARY TUBE IN THE PRESENCE OF SURFACTANT 1)

  • 摘要: 本文研究了竖直毛细圆管出口表面活化剂包覆液滴的形成过程。基于泰勒展开和润滑近似理论, 建立了液滴形成过程的一维动力学模型,并且通过坐标变换和有限差分的方法进行了数值求解。结果显示, 液滴自由面上表面活化剂包覆层可促进液滴颈部断裂,加快液滴头部与尾部锥形区的分离过程。与此同时, 还可增大颈部断裂前液滴下落的极限位移。与表面活化剂的活性相比, 液滴自由面上表面活化剂浓度的变化对液滴形成过程以及液滴形貌变化的影响更为显著。

     

    Abstract: In this study, the growth of an incompressible Newtonian drop from a vertical circular capillary tube in the presence of surfactant is analyzed. The flow is assumed to be axisymmetric and can be reduced to a spatially one-dimensional system by using the Taylor expansion and the lubrication approximation. The finite difference method combined with a coordinate transform is adopted for the numerical simulation. The results show that the existence of the surfactant will promote the breakup process of the drop, and prolong the limit length. Furthermore, the surfactant concentration has a more critical influence on the interface shapes than the surfactant activity.

     

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