Rise of a bubble through a self-rewetting fluid under the combined influence of gravity-driven convection and Marangoni convection

Abstract

In this study, the influence of gravity-driven convection and Marangoni convection due to the temperature-dependent surface tension gradient on the rise of an axisymmetric bubble moving in another fluid in a self-rewetting system inside a rectangular tube is studied in the presence and absence of a magnetic field. The axisymmetric bubble (fluid 1) moving in another fluid (fluid 2) is considered immiscible. A two-dimensional cylindrical polar coordinate system has been chosen to present the sketch of the problem. Partial differential equations governing the mentioned flow situations are written and converted into non-dimensional forms and their analytical solutions have been obtained. The deformation in the bubble in the form of its radius and length is simulated. The motion of the droplet is also analysed in the microgravity region by graphing the position of the bubble. The graphical results show that there is a decrease in the contribution of the Marangoni effect and gravitational effect when the magnetic field is increased. In the absence of a magnetic field, the contribution of both the Marangoni effect and gravitational effect decrease on increasing the relative viscosity.