A numerical study of water based Al2O3 and Al2O3–Cu hybrid nanofluid effect on forced convective heat transfer

• CFD modeling of hybrid nanofluid's effect on Nusselt number.
• Good agreement between simulation results and experimental data.
• Addition of nanoparticles enhance heat transfer coefficient.
• Obtaining higher Nusselt number for hybrid nanofluid.
• Represent two correlations for average Nu number & friction factor based on dimensionless numbers.

In this work, a CFD modeling of a horizontal circular tube was presented to investigate the effect of nanofluids on laminar forced convective heat transfer. The water-based Al2O3 and Al2O3–Cu hybrid nanofluid with 0.1% volume concentration and average particle size of 15 nm was considered. The solutions were based on both single- and two-phase approaches. The results showed a higher convective heat transfer coefficient for the hybrid nanofluid. In comparison to the single phase approach, the proposed mixture model revealed a better agreement with the experimental data. An energetic performance of fluid flowing was evaluated too. For these hybrid nanofluids, the average Nusselt number increase was 4.73% and 13.46% in compared to Al2O3/water and pure water, respectively.