Numerical Study on Taylor Bubble Formation in a Micro-channel T-Junction Using VOF Method

Abstract

A volume of fluid (VOF) method is used to study the immiscible gas–liquid two-phase flow in a microchannel T-junction, through which the accurate interface of the Taylor bubble flow inside the micro-channel is captured and compared with visualization experiment of Taylor bubbles’ generation inside a T-junction microfluidic chip. The numerical results are in good agreement with the experimental measurements, which confirms the validation of our model. Then the length of gas–liquid slugs and velocity distribution inside slugs at various conditions are investigated with the superficial velocity of gas and liquid phase ranging from 0.01 to 0.90 m/s, and capillary number ranging from 6.4 ×10 − 4 to 1.7 ×10 − 2. A comprehensive description of mechanism of bubbles’ break-off is achieved and the transition capillary number from squeezing regime to shearing regime is found around 5.8 ×10 − 3. Finally the influences of fluid viscosity, surface tension of the gas–liquid interface and the velocity of both gas and liquid phases on the characteristic of the gas–liquid two-phase flow in micro-channel are also discussed in detail.