Slug flow heat transfer in microchannels: A numerical study

Two-phase microchannel slug flow has attracted significant interest among researchers due to its wide range of applications. This paper will present some as yet overlooked features of slug flow heat transfer in microchannels, using numerical simulation. Numerical simulations are carried out using ANSYS FLUENT with the volume of fluid (VOF) method with a 2D axisymmetric geometry for a 100 µm inner diameter microchannel with constant wall temperature boundary conditions. Effects of slug flow parameters on heat transfer are discussed showing the heat transfer rate follows a similar trend to existing numerical results. Our results show a significant increase in Nusselt number with liquid-liquid two-phase flow compared to single-phase flow, by up to 200%. The study revealed that capillary number, size of the liquid slugs, as well as the liquid film thickness have an important impact on heat transfer.