Analysis of flow and heat transfer characteristics in truncated branching microchannels

Purpose This paper aims to design a novel truncated branching microchannel heat sink structure to improve thermal performance. Design/methodology/approach Numerical simulations were used to systematically investigate the effects of two- to five-stage (Cases 2–5) truncated branching configurations on flow and heat transfer characteristics. A comprehensive performance evaluation criterion (PEC) was applied to assess the different structures. Findings The results indicate that the truncated structure significantly alters hydrodynamic characteristics by inducing vortex concentration and periodically disrupting the thermal boundary layer, keeping it in a thin redeveloping state. This significantly improves heat transfer efficiency and temperature uniformity. Case 5 exhibits optimal performance. Within the Re range of 200–1200, temperature decreases as Re increases. The Nu reaches a maximum of 86.9 at Re = 1200, which is 2.89 times that of Case 1. The PEC values for Case 3, Case 4 and Case 5 increase with Re. At Re = 1200, the Case 5 structure demonstrates the optimal comprehensive performance with a PEC value of 1.39, which is significantly superior to those of the other structures. Originality/value This paper introduces a novel truncated branching microchannel heat sink design, which uses the expansion–contraction effect in the truncated regions to induce strong transverse flow and vorticity distribution, thereby disrupting boundary layers and enhancing fluid mixing. This provides an effective solution for high heat flux thermal management by significantly improving heat transfer efficiency and temperature uniformity.