Analysis of rheological behaviors of two-dimensional emulsion globules with asymmetric internal structures in modest extensional flows

Abstract

The rheological behaviors of complex emulsion globules (CEGs) and its three asymmetric daughter droplets (DDs) have been studied numerically in this paper. Unlike simple eccentric emulsion globules (SEEGs), two more DDs are added into the globules and the three DDs are located initially in an asymmetric distribution with a triangular shape. Through this investigation, an oriented shift and an inverse of CEGs are observed. Especially, the movement of CEGs under more conditions is still caused by the interaction of the asymmetric inner pressure distribution and the total outer drag force. Due to the asymmetric internal structure, the deformation of CEGs caused by the outer flow is asymmetric and so is the interfacial curvature which results in the oriented inner circulation. Compared to SEEGs, the addition of two extra DDs leads to the bigger deformation of CEGs, and more CEGs will shift to the left in the parameter range of our investigation. The increases of the parameters in the discussed ranges will promote CEGs to move to the right. In addition, DDs will move away from the original position and move away from or close to the interface of the mother droplet (MD), which may result in interface contact between DDs and MD. The results investigated in this paper further prove the mechanical mechanism of the oriented shift of the complex emulsions globules and are helpful to the controllable movement of soft globules driven by the asymmetric curvatures.