Formation of gas-liquid slugs in millimeter-scale T-junctions - Slug size estimation framework

Gas-liquid slug flow in micro/millimeter-scale channels is preferred in a broad range of applications because of its high mass and heat transfer rates. In most applications, the size of slugs needs to be precisely known, as the mass transfer characteristics are influenced by the slug length and its velocity. Here, a formation mechanism of gas-liquid slug is explored for the millimeter-scale T-junctions, which is different from that reported for micrometer-scale ones, and a framework is newly presented for the estimation of the slug size, which is based on a mass balance. As opposed to the gas slug size determined solely by channel geometry and liquid to gas flow ratio for micrometer-scale case, the size is strongly influenced by liquid and gas velocities.