Thermal hydraulic performance of tree-like microchannel heat sink with high branching level based on the improved Murray's law

Abstract

Based on the traditional Murray's law, the tree-like microchannel heat sinks (TLMHSs) cannot distribute the branching microchannels in given heat source region, so they cannot fully match exactly with the chips. This causes that their heat dissipation capacity is not very outstanding among various heat dissipation methods, and cannot be employed as a cooling method for chips with high heat flux. This paper improves the Murray's law and enables high-level branching microchannels to cover the whole region of heat source. Based on the modified Murray's law, the TLMHSs with evenly-distributed high-level microchannels (TLMHS-Ms) are proposed and their flow and heat transfer characteristics are analyzed numerically using the commercial software Fluent. The results indicate that the improved Murray's law can avoid obvious non-branching region found in the conventional TLMHSs (TLMHS-Cs). Compared with the TLMHS-Cs, the TLMHS-Ms possess the lower maximal temperature, temperature difference and thermal resistance. Depending on the aforementioned superior heat dissipation properties, the TLMHS-Ms can afford the higher heat flow under the same conditions. It is also found that the higher branching levels in the TLMHSs tend to reduce the maximal temperature, temperature difference, thermal resistance, Nusselt number and pressure drop, but the higher coefficient of performance. Among all TLMHSs, the TLMHS-Ms with kmax=6 can afford the largest heat flux of 264 W/cm2. This work can provide a novel TLMHS with evenly-distributed high-level microchannels for cooling the chips with high heat flux.