CFD study of constructal microchannel networks for liquid-cooling of electronic devices

Highlights: • Constructal-inspired scaling ratios were used to analyze different heat sink configurations. • Heat dissipation was improved with branched microchannel networks. • Thermal-hydraulic behavior was numerically compared for different designs. • A comparison was carried out for ratios different than the golden number and the allometric ratio used in this work. • The best performance was obtained with a geometrical channel ratio of 1.618 (golden number). - Abstract: The heat transfer performance of liquid-cooled heat sinks with a constructal design of the flow field configurations is assessed in the present investigation. Y- and Ψ-shaped microfluidic networks embedded on a silicon substrate are numerically analyzed and compared in order to propose an alternative cooling layer for integrated circuits (ICs). The shape, path and geometric dimensions of the flow channels are designed with the Phi number and Allometric scaling laws based on constructal networks, resulting in tree-shaped flow paths with variable hydraulic diameter. The thermal and hydraulic performances of eight different configurations are discussed in terms of the average surface temperature and pressure drop, respectively. Results indicate that the Ψ-shaped heat sink designs offer a higher degree of temperature uniformity than Y-shaped designs, with the penalty of a slightly higher flow restriction. It was observed that the Phi number ratio has a strong effect on thermal performance, with enhanced results for higher ratios. Discussions about heat transfer area, temperature uniformity and pressure drop are given for the different cases, proposing an enhanced design for electronics cooling applications.