Numerical simulation of cooling performance of an exhaust gas recirculation (EGR) cooler using nano-fluids

A numerical model is developed to predict the performance of an exhaust gas recirculation (EGR) cooler using nanofluid as the coolant. The model accounts for turbulent flow of coolant and hot smokes on an integrated computational domain. Thermal and hydrodynamic behavior of four nanofluids comprising water as the base fluid and SiO2, TiO2, Al2O3 and Cu nanoparticles, were compared over a wide range of Reynolds numbers and various particle concentrations. The accuracy of predictions was verified by experimental data available in the literature. The Al2O3-water nanofluid was found to provide the greatest heat transfer enhancement. Quantitatively, Al2O3-water nanofluid with a volume fraction of 5% and Reynolds number of 5000 improves the heat transfer coefficient by about 16% compared to pure water. However, it was found that the heat transfer enhancement was achieved at the expense of increased pressure drop due to greater viscosity of nanofluids compared to the base fluid. It was also found that the effectiveness of nanofluids in improving the heat transfer rate decreases as the Reynolds number increase.