Performance of an automotive car radiator operated with nanofluid-based coolant

Coolants such as water and ethylene glycol have been used traditionally in automotive car radiators. However, due to their low thermal conductivity a class of fluids known as nanofluids is used to enhance heat transfer characteristics. Nanofluids are suspended metallic or nonmetallic oxide nanoparticles in traditional heat transfer fluids that have bulk thermal conductivity higher than that of the base fluids. This experimental study is based on the application of an aluminum oxide (Al₂O₃)-based nanofluid with water as a base fluid in automotive car radiators. The effect on the overall heat transfer coefficient, heat transfer rate, and pressure drop are calculated by varying the percentage volume fraction of nanoparticles in water, volume flow rate of the nanofluid, and also the inlet temperature of the nanofluid. It is observed that as the nanoparticle concentration increased, the overall heat transfer coefficient and heat transfer rate increase, peaking at 0.8%. As the inlet temperature of the nanofluid increases, the overall heat transfer coefficient was found to be increasing. For a nanoparticle concentration of 0.8% with water, for a flow rate of 3 LPM and for inlet temperature of 80^oC, the overall heat transfer coefficient and heat transfer rates were increased by 36.27% and 25.95%, respectively, when compared to pure water.