LAUSR

Abstract In recent periods different categories of commercial products as coolants of the automobile radiators by different ratios of EG/water-based are manifested based on the climatic zones as tropical, arid, Mediterranean, temperate, continental, and polar. Nevertheless, little data are available to evaluate the thermal performance of the proposed fluids with different ratios of EG, so more studies are required to determine its impact on the heat transfer rate especially when mixed with nanomaterials. In this study, the performance characteristics of the vehicle radiator are experimentally carried out under the hot arid climate of Cairo-Egypt at relevant parameters leading to design optimization. This investigation is covered by different parameters such as nanoparticle concentrations, nanoparticle types, fluid type, fluid temperature, and mass flow rate. Two types of nanoparticles are examined, as (Al2O3) and cobalt oxide (Co3O4) at concentrations of 0.02, 0.05, 0.1, and 0.2%. The nanoparticles are dispersed into a base fluid to produce a mixture of nanofluid. The base fluids are prepared by considering three ratios of EG/water at 0:100%, 10:90%, and 20:80%. Experiments are accomplished in a pilot air duct with a constant air velocity of 0.6 m/s whilst the fluid mass flow rate is varied in the range 0.05–0.2 kg/s. A thermo-hydrodynamic performance index is presented to appraise the impact of Co3O4/(CH2OH)2-H2O and Al2O3/(CH2OH)2-H2O with particular reference to pure water. The results reveal that the cobalt oxide-based water exhibits high thermal performance than alumina. A higher value of the performance index is observed at a lower concentration ratio and a higher Reynolds number. The addition of EG decreases the Nusselt number and increases the pumping power in comparing with pure water. Correlations of Nusselt number, friction factor, and radiator effectiveness expressing the results are also derived.