Heat transfer performance and exergy analyses of MgO and ZnO nanofluids using water/ethylene glycol mixture as base fluid

Forced laminar convective heat transfer of MgO and ZnO nanofluids through flat tube automobile radiator was studied numerically using 0.25-3ć volume concentrations at Reynolds number ranges (250–1750) for both nanofluids. The results showed an increase in the convective heat transfer coefficient 13.76% and 17.1% at 3% concentration of ZnO and MgO nanofluids, respectively, relative to water/ethylene glycol mixture (50:50 by vol%.) as a base fluid. However, increasing the volume concentration caused an increase in the pumping power For same heat rejection of W/EG mixture, a reduction of about 4.15% and 3.1% in radiator surface area was obtained at 1% concentration of MgO and ZnO nanofluids, respectively. A decrease in total exergy destruction rate of 15.7% and 12.2% compared to the base fluid was obtained for 3 vol% of MgO and ZnO nanofluids, respectively, at Re = 1750.