A COMPREHENSIVE REVIEW OF HEAT TRANSFER IN POROUS MEDIA: FOCUSING ON NANOFLUIDS, PHASE CHANGE MATERIALS, AND NANOENCAPSULATED PHASE CHANGE MATERIALS

This research investigates the recent advancements in heat transfer through nanofluids in porous media. We seek to conduct a comprehensive review of the most influential papers published since 2020, aiming to contribute significantly to this field. Initially, key parameters affecting heat transfer in porous media, such as porosity, permeability, pore shape and size, and other factors are introduced. Subsequently, the primary heat transfer mechanisms, the impact of flow velocity and patterns, heat transfer rates, thermal equilibrium and nonequilibrium conditions, and techniques to enhance heat transfer, including nanomaterials and phase change materials, are explored. Following an introduction to nanomaterials and their various types, this study delves into the methodologies for their synthesis and thermal conductivity models. Additionally, phase change materials are categorized as another effective approach to enhance heat transfer, and methods for improving their thermal conductivity are explored. A comprehensive review of recent studies, presented in tabular form, reveals that the highest heat transfer coefficient and Nusselt number for nanofluids were attained at a 30° angle and with a square porosity. In forced and mixed convection scenarios, increasing porosity and the length of the heat source led to a higher Nusselt number, whereas increasing the Hartmann number resulted in a decrease. Furthermore, a comprehensive statistical analysis of heat transfer in porous media using nanofluids demonstrated that Al₂O₃– water nanofluids with a 28.33% concentration, cylindrical geometry with 27.78%, and the Darcy–Brinkman model with 33% exhibited the most significant contributions.