A numerical investigation of thermally mediated droplet formation in a T-junction

The present article presents a numerical investigation on the effect of thermal forcing for droplet formation in a T-junction. Thermal forcing, generated by a heater embedded into the channel wall, induces a non-uniform temperature field which results in the variation the fluids' properties and affects the droplet formation process in a desirable manner. In the present article, droplet formation process is posed as an incompressible immiscible two-phase flow problem with the motion of the two-phases strongly coupled via the related interfacial conditions. It is governed by the three-dimensional Navier-Stokes and the energy equations. The interface is captured with a narrow-band particle level-set method. Solutions are obtained using a finite volume method on a staggered mesh. The numerical model is validated against droplet formation in a cross junction. With the formation of water droplet in oil within the squeezing formation regime as a case study, the physics underlying droplet formation process in a T-junction affected by a thermal forcing is investigated. The combined effect of variations in both viscosities and surface tension result in a larger droplet. It is believed that the behavior of fluids system under an imposed thermal forcing depends strongly on the characteristics of temperature dependent viscosities and surface tension.