Deformation and Interaction of Droplet Pairs in a Microchannel Under ac Electric Fields

A numerical study of droplet deformation in a flat funnelform microchannel

Motivated by recent reported experiments, droplet deformation in a flat funnelform diverging microfluidic channel has been numerically studied. The structure of our microchannel is composed of two consecutive elements including a straight channel and a diverging channel. In this work, instead of solving the 3D Stokes equation, we solve a depth-averaged problem which is labeled two-dimensional p...

Response of shear stress to ac electric fields under steady shear flow in a droplet-dispersed phase.

We have measured the response of shear stress to ac electric fields under steady shear flow in the droplet-dispersed phase of an immiscible polymer blend. A characteristic mode was found under steady shear flow, the relaxation frequency of which increased with increasing the shear rate. In the frequency dispersion, a scaling relation derived from dimensional analysis was confirmed to hold. The ...

Electrochemical Processes in Microfluidics Systems under Ac Electric Fields

Microfluidic flow-focusing in ac electric fields.

We demonstrate the control of droplet sizes by an ac voltage applied across microelectrodes patterned around a flow-focusing junction. The electrodes do not come in contact with the fluids to avoid electrochemical effects. We found several regimes of droplet production in electric fields, controlled by the connection of the chip, the conductivity of the dispersed phase and the frequency of the ...

Dynamic and Deformation of a liquid Droplet in a Convective Two-Dimensional Laminar Flow

The objective of this research is to develop an accurate numerical method to be used in showing the deformation of a liquid fuel droplet in a convective field. To simultaneously solve the internal liquid droplet flow field as well as the external gas phase flow field, a nonstaggered rectangular grid system without any coordinate transformation is used. Transition from the gas field to the liqui...