Dynamics Of Droplets Driven By Electric Field

The dynamic characteristics of the micro-and nanoscale fluid in electric field attracts much attention.With the decrease of the droplet size,the effects of the various surface tension of fluid and the coalescence of the droplet in electric field receive extensive concern.The combination of theoretical deduction and numerical simulation is adopted in this research.Evolution and coalescence model of fluid induced by electric field was established basing on leaky dielectric model.PEDCOL code was utilized to simulate the dynamics and coalescence of a conductive droplet in the presence of diverse electric fields,mainly includes the following contents:(1)The spreading of droplets between two plate electrodes is not only related to electric potential type,also related to change under the action of surface tension due to electric field.The influence of the proportion coefficient of surface tension on the droplet movement process is approximately same while the maximum thickness of liquid film and spreading radius variation rate are obviously different.Exerting uniform and linear electric potential does not alter the parabolic shape of spreading droplet.With the increase of the proportion coefficient,the droplet spreading is accelerated.Under the condition of nonlinear electric potential,the appearance time of indentation at liquid film center tends to be longer,the breakage possibility is decreased.Rupture process of a droplet can be controlled by applying exponential electric potential.The greatest impact of the variation of surface tension on the process of a droplet spreading is linear potential,and the least impact is exponential potential.(2)The coalescence process of two droplets produce is inhibited by electric field.The influence of different potential on the droplet coalescence process is not the same.The influence of the linear electric potential is mainly appear as the promotion of the overall migration of the two droplets and inhibition of the coalescence of the droplets.The droplets in electric field gather and form a main droplet,which is similar in shape of a arch.The electric field force in undulating electric potential influence increases then the coalescence process is inhibited even the droplets do not coalesce into one main drop.It embody that by changing the parameters of the electric field can control the droplet coalescence process.