A review on heat transfer and hydrodynamic characteristics of nano/microencapsulated phase change slurry (N/MPCS) in mini/microchannel heat sinks

Mini/microchannel heat sinks are currently widely used in a variety of thermal and energy applications with the advantages of compactness, light weight and higher heat transfer performance. In order to further improve the performance of such heat sink, many recent studies have introduced the nano/microencapsulated phase change slurry (N/MPCS) as the working fluid due to their high storage capacity during phase change. This paper concerns the channel with hydraulic diameter from 10 μm to 3 mm, covering the range of microchannel and minichannel. Firstly, the existed review works relate to mini/microchannel heat sinks are summarized, with topics covering manufacturing processes and geometric designs, thermal and hydrodynamic performance with different working fluids, and their typical and potential applications. Then, the N/MPCS used in mini/microchannels from experimental and numerical simulation works are discussed, with focuses placed on the base fluid, core and shell materials, and thermophysical properties of slurry. Next, the local, average and overall heat transfer and hydrodynamic characteristics of mini/microchannel heat sinks with N/MPCS flowing inside are reviewed and analyzed, considering different flow conditions, material and dimension of test section, and composition and fraction of such slurry. Finally, the proposed heat transfer and pressure drop correlations in this research field are evaluated. The purpose of this review article is to provide exhaustive and comprehensive study of recent published works in this new area and supply useful information for the design of compact heat exchangers and thermal storage systems with N/MPCS as working fluid.