Liquid film transport around Taylor bubble in a microchannel with gas cavities

Abstract

In Taylor flow, the low velocity in liquid film around the bubbles limits the mass transfer between the bubble body and liquid phase. To overcome this deficiency, a cross-junction Microchannel with gas Cavities (MGC) is designed and processed. The restricted inert nitrogen in the gas cavities provided partial slip boundaries, which makes it distinctive from the conventional Straight Microchannel (SM). The liquid film thickness and velocity distribution in the liquid film are investigated. It is found that the bubble shape in MGC is more sensitive to the capillary number. A thicker liquid film and a sharper bubble shape can be observed under the same operating conditions. These changes lead to a larger specific surface area (about 110 % of SM) and a remarkable increment of leakage flow rate (132.2–181.1 % of SM). Then, the intensifying mechanism of liquid transport in the liquid film is analyzed by numerical simulation. The results reveal that the slip and radial fluctuation of velocity at the gas cavity interface prominently improved the liquid transport. The high specific surface area and strong renewal ability of liquid film demonstrates a great potential for mass transfer in MGC.