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

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 x10 (-aEuro parts per thousand 4) to 1.7 x10 (-aEuro parts per thousand 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 x10 (-aEuro parts per thousand 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.