Cooling performance investigation of nanofluids for internal combustion engine systems

This study aims to evaluate numerically the cooling performance increase of an internal combustion engine cooling system due to the use of nanofluids. Throughout the study a set of analyses has been done to determine the performance enhancement due to addition of nanoparticles; and the performance enhancement for two nanoparticle materials, alumina and hexagonal boron nitride (hBN) is compared. First, numerical model verification is done for diamond and TiO2 containing nanofluids, comparing the model results with experimental results. Then an uncommon material in nanofluid literature, hexagonal boron nitride is introduced and its thermal performance is investigated in a horizontal tube and in turbulent regime. As a final analysis, a car radiator flow channel is modeled numerically to investigate the cooling performance of nanofluids. Water and ethylene glycol (EG) mixture (50% - 50%) is chosen as base fluid for the radiator analysis, in which the effects of two nanoparticle materials, alumina and hexagonal boron nitride in various particle volumetric concentrations up to 5% are evaluated and compared. Thermal performance increase, in terms of radiator cooling capacity increase is evaluated with respect to particle volumetric concentration, air side convection and radiator frontal area. As a result, it is shown that hexagonal boron nitride containing nanofluids have superior thermal performance with respect to alumina containing ones. However, the results indicate limited thermal performance improvement for the investigated cooling system by the use of nanofluids in general.