Numerical Simulation for Analyzing Interfacial Velocity and Interfacial Forces of a Bubble Motion in Taper Micro Gap

Abstract

Heat transfer due to the convective boiling mechanism in the microchannel plays an important role in heat transfer during boiling. Therefore, it is relevant to find ways to manipulate the vapor bubbles such that convection heat transfer is enhanced. This numerical study investigates the effects of different geometrical parameters on bubble movement through a micro tapered gap. The objective is to identify an optimal configuration such that the bubble moves at the fastest possible speed when it travels through the micro gap. To conduct this research a model is created using ANSYS-Fluent which uses the Volume of Fluid (VOF) interface tracking method. The multiphase VOF model tracks the air-water interface. A bubble is generated inside the microchannel in which fluid is flowing. The overall domain of the model consists of the surface at the bottom, having an orifice through which the air bubble is generated. Three different cases of an angled tapered surface are created 5°, 10°, and 15°. The airflow rate is kept constant throughout each simulation. Simulation results show the impact of the tapered angle on the bubble’s flow movement and flow direction. Liquid and air velocity contours can be used to analyze the flow. The impact of the taper angles on the movement and flow direction of the air bubble is discussed. It is observed that the performed simulations help to better understand the experimental observation of bubble motion; the simulations give clear evidence of the fluid dynamic behavior along the tapered microchannel.