Gas–liquid Taylor flow in square micro-channels: New inlet geometries and interfacial area tuning

Effects of different T-junction injectors on the generation of a N2–water Taylor flow has been investigated experimentally in a channel of 300 μm by 300 μm. 4 different inlet geometries and 2 feeding configurations are evaluated in a wide range of fluid flow rates ratio 0 < QG/QL < 35. It has been demonstrated that for a given flow rate ratio different patterns of the unit cell (1bubble + 1 slug) can be formed showing the impact of inlet geometries. An attempt to rationalize the result is proposed using a Garstecki-type scaling law for bubble length prediction. A unique geometrically based scaling law is discussed and a quite good agreement is obtained to describe the whole set of experiments, provided that there is no bubble coalescence:LbubblewG=1.03⋅wG⋅wLwchannel20.33+2.17⋅wGwL⋅UGULFinally an analysis in terms of specific interfacial area location (caps or bubble body) is proposed showing the interest of such inlet geometries to tune this parameter for fixed fluid flow rates and opening new possibilities for local mass transfer studies in the G–L Taylor flow configuration in square micro-channels.