Effect of Al2O3–Cu/water hybrid nanofluid in heat transfer

In this experimental work, a fully developed laminar convective heat transfer and pressure drop characteristics through a uniformly heated circular tube using Al2O3–Cu/water hybrid nanofluid is presented. For this we synthesized Al2O3–Cu nanocomposite powder in a thermo chemical route that involves a hydrogen reduction technique and then dispersed the prepared hybrid nano powder in deionised water to form a stable hybrid nanofluid of 0.1% volume concentration. The prepared powder was characterized by X-ray diffraction and Scanning Electron Microscope to confirm the chemical composition, to determine the particle size and to study the surface morphology. The convective heat transfer experimental results showed a maximum enhancement of 13.56% in Nusselt number at a Reynolds number of 1730 when compared to Nusselt number of water. The experimental results also show that 0.1% Al2O3–Cu/water hybrid nanofluids have slightly higher friction factor when compared to 0.1% Al2O3/water nanofluid. The empirical correlations proposed for Nusselt number and friction factor are in good agreement with the experimental data.

► Synthesis and characterization of alumina–copper hybrid particles using a thermo-chemical method.
► Preparation of alumina–copper/water hybrid nanofluids by dispersion of synthesized hybrid particles in deionised water.
► Heat transfer and pressure drop studies of prepared hybrid nanofluid with volume concentration 0.1%.
► Significant enhancement in convective heat transfer due to the addition of synthesised hybrid particles compared to water.
► Empirical correlations proposed for Nusselt number and friction factor agree well with the experimental results.