Splitting of droplet with different sizes inside a symmetric T-junction microchannel using an electric field
Keivan Fallah, Ehsan Fattahi
Abstract
Abstract In the current study, droplets dynamics under an asymmetric electric field in a T-junction are numerically studied using COMSOL Multi-physics software. The effect of different factors such as dimensionless length of mother droplet (L * ), Capillary number (Ca), and electric capillary number (Ca e ) are investigated on the breakup process in symmetric T-junctions. Two novel patterns of droplets, namely, hybrid asymmetric splitting mode and sorting patterns, have been observed by imposing an electric field in one branch of the microchannel. It is also concluded that using an electric field is a promising strategy to reach droplets with arbitrary sizes and control over the splitting ratio of daughter droplets precisely in a T- junction by adjusting the electric field strength. After a certain electric capillary number ( $$\left. {Ca_{e} } \right|_{Sorting}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mfenced> <mml:mrow> <mml:mi>C</mml:mi> <mml:msub> <mml:mi>a</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:mrow> </mml:mfenced> <mml:mrow> <mml:mi>Sorting</mml:mi> </mml:mrow> </mml:msub> </mml:math> ), the mother droplet does not breakup and is sorted on the side of the branch that the electric field imposes. Furthermore, $$\left. {Ca_{e} } \right|_{Sorting}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mfenced> <mml:mrow> <mml:mi>C</mml:mi> <mml:msub> <mml:mi>a</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:mrow> </mml:mfenced> <mml:mrow> <mml:mi>Sorting</mml:mi> </mml:mrow> </mml:msub> </mml:math> increases with the increment of L * and Ca.