Internal convective heat transfer of nanofluids in different flow regimes: A comprehensive review

This manuscript presents detailed literature related to the studies of convection heat transfer of nanofluids in different flow regimes for different heat transfer devices like tubes, heat sinks, heat exchangers, etc. Convective heat transfer and friction factor for laminar and turbulent flow regimes are discussed in detail and available studies for transition flow regime are also compiled. Additionally, this review reports Nusselt number and friction factor correlations under different flow regimes with their limitations. Authors have highlighted the effect flow regime, type of nanofluid used, size of the nanoparticle, temperature, clustering, and concentration of nanoparticles (NPs) on the thermal characteristics of nanofluid. The generalized models and correlations developed based on experimental results under different flow regimes are also summarized with their limitations. The remarkable enhancement in heat transfer is mostly reported for turbulent flow regimes, but at the expense of greater pressure drop as compared to laminar flow.