Abstract
Gas-liquid and liquid-liquid multiphase flows are often encountered in application of microreactors. When two immiscible fluids are introduced to a microchannel, several flow patterns may be observed depending on the fluid property, flow conditions, and the channel geometry. Slug flow is the most important flow mode among them, because the mass transfer rate across the fluid interface is greatly enhanced. The enhancement of the mass transfer was attributed to the recirculating flow within each slug, which promotes the mass transfer from the fluid interface to the interior of each slug. Thus, it is important to clarify the range of operating conditions in which slug flow can be formed. Also, to fully understand the mass transfer enhancement in slug flow regime, the fluid behavior in each slug must be studied. Many studies have been conducted to construct a general flow regime map. Also, the fluid flow within a slug has been investigated by utilizing flow visualization techniques and computational fluid dynamics simulations. This article gives an brief overview of the studies on the characteristics of multiphase flow in microchannels.
