Numerical and experimental investigation into the impact of cu/al2o3 hybrid nanofluid and higher concentration alumina nanofluids on heat transfer in a two and three-channel heat exchanger

The following work was conducted both numerically and experimentally with two nanofluid types being investigated. The first being a Cu/Al₂O₃ 2O3 hybrid nanofluid with an aluminum oxide nanostructure decorated in copper oxide nanostructures, and the latter being two higher concentration alumina nanofluids, 1% vol and 2% vol created through dilution of a stock fluid in distilled water. Both nanofluids were tested in a fluid flow system filled with an open-cell foam metal. The porous media is comprised of a 6061-T6 aluminum with a permeability of 9.54788× 10−7 m² for the hybrid nanofluid and a permeability of 2.3869 x 10^-7 m² for the high concentration alumina nanofluid, with both porous media blocks used in the investigation having a porosity of 0.91. The experiments were conducted with varying heat flux. The performance of the nanofluids was evaluated by examining changes in the Nusselt number. The copper oxide/alumina nanocomposite in conjunction with the porous media, resulted in a significant enhancement of 6-11% compared to the commercially available alumina nanofluid, The high concentration alumina saw an average thermal enhancement of 15.6% of the 1% vol nanofluid over the 2% vol.