Application of nanofluids under laminar flow regime in heat exchangers—a review

Nanofluids, characterized by their enhanced thermal conductivity due to the dispersion of nanoparticles, have emerged as a promising solution to improve heat transfer efficiency in industrial and non-industrial processes. This review focuses specifically on the behavior, characteristics, and applications of nanofluids under laminar flow conditions. The objective is to consolidate experimental, theoretical, and numerical research concerning heat transfer enhancement in low-Reynolds-number systems such as microchannels and compact heat exchangers. Particular emphasis is placed on thermophysical properties, performance comparisons, and flow behavior of nanofluids when viscous forces dominate the flow regime. The review highlights the advantages of nanofluids over conventional heat transfer fluids—such as water and mineral oil, particularly in laminar flow Heat exchanger applications. Through a comprehensive analysis of recent research, this paper examines the mechanisms by which nanoparticle properties, including size and material type, influence thermal performance and flow behavior. The insertion of nano particles with diameters less than 100 nano meter or fiber suspension can significantly improve the thermal properties of general fluid. Spread out, wetting, diffusion, and stability, as well as acceptable viscosity has been increased of a solid surface when a layer of nanofluid is applied on it. Nanofluids has diversified role in thermal engineering systems, including heat exchangers, refrigeration, nuclear reactor cooling, micro electromechanical systems, and others. Thermal conversion, in particular, is recognized as a significant application of nanotechnology, and numerous studies have been conducted using such fluids in the heat exchangers. Key findings highlight the significant enhancements in heat transfer and thermal stability, alongside challenges such as viscosity management and particle stability. The implications of these findings for advanced thermal systems, including plate-fin and heat pipe heat exchangers, are discussed. This review aims to provide researchers and engineers with an informed perspective on the potential and limitations of nanofluids, guiding future innovations in thermal engineering applications.