Numerical study of thermocapillary migration of a bubble in a channel with an obstruction

Abstract

Fully resolved numerical simulations are used to examine the thermocapillary motion of a two- and three-dimensional fully deformable bubble in a channel with an obstruction. A front-tracking/finite volume method is used to solve the Navier-Stokes equations coupled with the energy conservation equation. The results show that, for a fixed obstruction and channel size, the influence coefficient α, defined as the ratio of arrival time in channels with and without an obstruction, increases with increasing Marangoni (Ma) number for both two- and three-dimensional flows, whereas an increase in the Reynolds (Re) number leads to an increase in the influence coefficient in two-dimensional flows but a decrease in three-dimensional flows. Moreover, a change in the Capillary (Ca) number does not have a visible effect on the thermocapillary motion if the width of the narrow part of the channel is larger than the bubble diameter. Results for both two- and three-dimensional flows show that the influence coefficient increases dramatically with an increase in the obstruction size W, and a larger obstruction makes the dependence of α on the fluid parameters more obvious.