Oladetan, Jeremiah O.Fujah, Faridat M.Omosehin, Oluwasegun S.Atofarati, Emmanuel O.Nwabuko, UzoOlakoyejo, Olabode T.Adelaja, Adekunle O.2025-10-162025-10-162025-07Oladetan, J.O., Fujah, F.M., Omosehin, O.S. et al. Numerical Investigation of Heat Transfer Performance of Hybrid Nanofluid in Porous Substrate in Microchannel Heat Sink. International Journal of Applied and Computational Mathematics 11, 151 (2025). https://doi.org/10.1007/s40819-025-01973-z.2349-5103 (print)2199-5796 (online)10.1007/s40819-025-01973-zhttp://hdl.handle.net/2263/104745DATA AVAILABILITY: Data will be made available on request.With the increasing integration of integrated circuits (ICs) in electronic devices such as electric vehicles, computer data centers, heat pipe technology, solar energy, and heating ventilation, air conditioning, and refrigeration (HVACR) systems, optimizing heat transfer becomes essential to ensure optimal performance and longevity. This study numerically investigates the thermal and hydraulic performance of a microchannel heat sink (MCHS) enhanced by hybrid nanofluids and porous substrate integration. A two-phase Eulerian–Eulerian model implemented in ANSYS Fluent is employed to simulate Al₂O₃/Cu–water hybrid nanofluid flow at volume concentrations ranging from 0.1 to 3.0%, and flow Reynolds number (200 < Re < 1000) with a porous substrate embedded midway along the flow path. The results reveal that both the nanoparticle concentration and Reynolds number significantly enhance heat transfer, reflected in higher average Nusselt numbers and reduced thermal resistance. The incorporation of a porous substrate further amplifies heat transfer, achieving a maximum enhancement of 80.29% compared to the baseline configuration. Overall, employing hybrid nanofluids and porous substrates improves MCHS performance, offering augmented heat transfer efficiency and thermal performance.en© The Author(s) 2025. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License.MicrochannelHeat sinkConvective heat transferPorous substrateHybrid nanofluidMicrochannel heat sink (MCHS)Article