Hybrid microchannel heat sink using tapered channels and interconnectors for microelectronics cooling

• A hybrid interconnected microchannel heat sink has been proposed. • The optimal design can handle ∼50 % higher heat flux than conventional microchannel. • Interconnector’s position and width have negligible effect on heat sink performance. In conventional single-phase parallel-flow microchannel heat sinks (MCHS), effectively dissipating high heat flux while maintaining uniform temperature distribution becomes a prominent issue. To address these challenges, this study introduces a novel hybrid MCHS design that incorporates a combination of straight and tapered channels, which are transversely linked via interconnectors (ICs). The cross flow through the ICs is driven by the pressure differential resulting from geometric variations among adjacent microchannels. The main idea of this study is to maintain the flow consistently within the thermally developing region by leveraging the favorable flow dynamics of tapered microchannels and induced cross flow through the ICs, thereby enhancing thermal performance. Six hybrid interconnected MCHSs (ICMCHSs), featuring straight, converging, and diverging microchannels along with four ICs, are designed. To compare the performance of the proposed ICMCHSs with the conventional MCHS, numerical simulations are conducted under single phase conditions with varying coolant volumetric flow rates, and various performance parameters such as pressure drop, cross flow rate, temperature non-uniformity, maximum sink base temperature, heat transfer coefficient, overall thermal resistance, pumping power, and performance evaluation criteria (PEC) are analyzed. Moreover, to reduce the computational cost, the analysis is limited to a representative unit comprising three microchannels. Among the proposed ICMCHSs configurations, the design with converging side channels and a diverging middle channel demonstrates the best overall thermo-hydraulic performance. For example, at 225 mL/min, this configuration achieves a 30 % increase in PEC, a 48 % reduction in temperature non-uniformity, and an 8 °C reduction in maximum base temperature, albeit with a 35 % average increase in pressure drop compared to the conventional MCHS. Moreover, it is observed that the variation of ICs’ location and width has no significant impact on the overall performance of the design mentioned above. Finally, this highlighted design is reported to handle approximately 52 % more heat flux within the temperature limit of 85 °C than that of the conventional MCHS. Overall, the present work offers a general guideline for thermal engineers seeking efficient solutions for microelectronics cooling by highlighting the coupled effect of channel tapering and interconnection features.