关键词: 双重乳液/
剪切流/
形变特性/
可视化
English Abstract
Steady deformation characteristics of double emulsion droplet in shear flow
Zhang Cheng-Bin1,Yu Cheng1,
Liu Xiang-Dong2,
Jin Ou2,
Chen Yong-Ping1,2
1.School of Energy and Environment, Southeast University, Nanjing 210096, China;
2.School of Hydraulic Energy and Power Engineering, Yangzhou University, Yangzhou 225127, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant No. 51306033) and the Natural Science Foundation of Jiangsu Province, China (Grant Nos. BK20130621, BK20140488).Received Date:18 May 2016
Accepted Date:09 August 2016
Published Online:05 October 2016
Abstract:The manipulation of double emulsion droplet via shear flow field is widely encountered in microfluidic devices. However, the interface evolution and hydrodynamics behavior of double emulsion droplet in shear flow is less understood till now. In this paper, a theoretical model of double emulsion droplet in a Couette flow device is developed and numerically analyzed to characterize the interface behavior of incompressible double emulsion droplet, which is also verified by a visualization experiment. Based on this model, the mechanisms underlying the steady deformation of double emulsion droplet under shear are investigated, and the effects of radius ratio of inner droplet to the outer one and viscosities of working fluids on the steady deformation are discussed. The results indicate that the steady deformation of double emulsion droplet in the shear increases with the rise in capillary number, and the deformation resistance of inner droplet is larger than that of the outer droplet. With increasing the radius ratio of inner droplet to the outer one, the interaction between the inner and outer droplets becomes great and thus the deformation degree of the inner droplet is increased. In addition, the effect of big deformation resistance by the inner droplet tends to be obvious, leading to decreasing the deformation degree of outer droplet. The viscosities of both inner and outer droplets provide a resistance for the deformation of double emulsion droplet. With the rises in viscosities of inner and outer droplets, the deformation degree of integral double emulsion droplet decreases. In addition, the effect of outer droplet viscosity on the steady deformation is more obvious than that of the inner droplet.
Keywords: double emulsion droplet/
shear flow/
deformation characteristics/
visualization
