Numerical study and moth flame optimization of thermal–hydraulic performance of fractal microchannel heat sink with ribs and cavity

Abstract

With the fast integration and shrinkage of electronic equipment, managing heat has emerged as a key roadblock to developing microelectromechanical systems. This investigation presents a bio-inspired fractal microchannel heat sink (FMCHS) design featuring ribs and cavities, which is motivated by the natural mass and energy transfer capabilities found in fractal structures. For an in-depth understanding of the thermal–hydraulic performance of an FMCHS, the branching ratios in successive tree-like structures are chosen via a parameter optimization process that prioritizes minimizing flow resistance. Different thermal and flow characteristics were analyzed numerically using Ansys Fluent, and these results were compared with a plain FMCHS (FMCHS-P). The outcomes suggest that incorporating variable cross-sectional structures can enhance the thermal performance of the FMCHS. FMCHS with ribs (FMCHS-R) and FMCHS with diagonally positioned ribs (FMCHS-DR) have the highest heat transfer performance, followed by FMCHS with cavities (FMCHS-C) and FMCHS with diagonally positioned cavities (FMCHS-DC), but at the same time, ribbed-configured FMCHS has the highest pressure drop. FMCHS models were optimized using ANN and the moth flame optimization (MFO) algorithm with the objective of maximizing Nusselt number and minimizing pumping power and thermal resistance. This research suggests that a model with FMCHS with ribs has an optimal geometrical configuration. The optimal input value is found to be 26 % of the rib radius along all the paths of FMCHS with ribs (FMCHS-R) at a flow rate of 200 ml/min.