Semnan University Press Journal of Heat and Mass Transfer Research 2345-508X Articles in Press 2026 01 04 Numerical Investigation of Nanofluid-Based Cooling in a Heat Sink-Inspired Cavity Using the Lattice Boltzmann Method 10407 10.22075/jhmtr.2026.38804.1815 EN Abdelilah Makaoui Mechanics & Energy Laboratory, Faculty of Sciences, Mohammed First University, Oujda 60000, Morocco Youssef Admi Mechanics & Energy Laboratory, Faculty of Sciences, Mohammed First University, Oujda 60000, Morocco Mohammed Amine Moussaoui Mechanics & Energy Laboratory, Faculty of Sciences, Mohammed First University, Oujda 60000, Morocco Ahmed Mezrhab Mechanics & Energy Laboratory, Faculty of Sciences, Mohammed First University, Oujda 60000, Morocco Journal Article 2025 08 25 The present study employs a two-dimensional numerical analysis of heat transfer enhancement in a heat sink-inspired cavity using nanofluids, based on the Multiple Relaxation Time Lattice Boltzmann Method. A systematic analysis is conducted to investigate the impact of nanoparticle volume fraction (φ = 0-5%), Reynolds number (Re = 10-500), and Richardson number (Ri = 0.1,1,10) on thermal performance. The findings of the study demonstrate that augmenting the nanoparticle volume fraction substantially enhances heat transfer, particularly at low Reynolds numbers (Re ≤ 100), where natural convection exerts a predominant influence. In the case of a 5% concentration, the average Nusselt number is observed to increase by more than twofold in comparison with the base fluid. This phenomenon can be attributed to the enhanced thermal conductivity resulting from the presence of the substance under investigation. However, this enhancement diminishes as forced convection becomes dominant at higher Re. The greatest thermal performance gains occur at Ri = 0.1, indicating strong forced convection. A thorough investigation into the thermal performance factor reveals that nanofluids demonstrate optimal efficacy in low-flow regimes.