Transient Thermocapillary Flows Induced by a Droplet Translating in an Electric Field

Abstract

A spherical dielectric droplet translating steadily in another dielectric liquid with a uniform electric field imposed in the translational direction of the droplet is studied theoretically. With the small Reynolds number and large Peclet number assumptions, analytic solutions are obtained for the stream function with a term involving the interfacial temperature distribution which is then computed numerically. The results indicate that the interfacial temperature distribution is indeed nonuniform and the thermocapillarity might exist thereby. The induced thermocapillary flows in the droplet are usually of multiple cells with which the heat transfer rate may increases or decreases depending on whether the original flow is enhanced or suppressed. For the example calculated in the present study, the heat transfer rate is decreased by the thermocapillary effect.