Thermal management of high-power electronics is a critical engineering challenge, with junction temperatures directly governing device reliability and failure rates. Micro-channel heat sinks (MCHS) offer significantly enhanced surface-area-to-volume ratios compared to conventional heat sinks, but their thermal performance is constrained by the thermophysical properties of the working fluid. Hybrid nanofluids — suspensions incorporating two or more nanoparticle species — present a promising avenue for augmenting convective heat transfer beyond what single-species nanofluids can achieve. This study presents a combined experimental and CFD investigation of Al₂O₃/TiO₂ hybrid nanofluid (60:40 volumetric ratio) at concentrations of 0.1%, 0.5%, and 1.0% vol. in a rectangular MCHS (Wₙ=300µm, Hₙ=600µm) over Re=200–900. The hybrid nanofluid at 1.0% vol. achieves peak Nusselt number enhancement of 38.4%, thermal resistance reduction of 29.6%, and a PEC of 1.31 — confirming net thermal-hydraulic benefit after accounting for the 18.7% pressure drop penalty. Maximum junction temperature is reduced by 11.4°C under 150 W/cm² heat flux. CFD velocity contours reveal secondary flow vortices near channel corners that contribute disproportionately to heat transfer augmentation at higher Re.
Arjun Krishnamurthy, Priya Subramaniam, Tanushree Bhattacharya (2026) studied this question.