Numerical Studies on Non-Boiling Two-Phase Flows in Microtubes and Microchannels: A Review

Numerical studies on the hydrodynamic and heat transfer characteristics of two-phase flows in small tubes and channels are reviewed. These flows are gas-liquid and liquid-liquid slug flows. The review is categorized into two groups of studies: circular and non-circular channels. Different aspects such as slug formation, slug shape, flow pattern, pressure drop and heat transfer are of interest. According to this review, there are some large gaps in the research literature, including pressure drop and heat transfer in liquid-liquid slug flows. Gaps in research are also found in applications of non-circular ducts, pressure drop and heat transfer in meandering microtubes and microchannels for both of gas-liquid and liquid-liquid two-phase flows.