Nanofluidos em um sistema de arrefecimento automotivo

Abstract

The present work evaluated the thermohydraulic performance of silver nanofluids based on a mixture of water and ethylene glycol (50:50) in an automotive radiator. Three nanofluid samples with volumetric concentrations of 0.001%, 0.002% and 0.003% were prepared and their thermal conductivity and viscosity were measured experimentally using a thermal conductivity meter and a rotational viscometer, respectively. For the thermal conductivity tests, the temperature range was from 25 to 55 ° C, and for viscosity, from 25 to 95 ° C. The thermohydraulic performance evaluation was conducted on an experimental bench that allows a controlled simulation with similar operation conditions of an automotive cooling system. The temperature of the air flowing to the radiator was mantained constant at 25°C, and the mass flow of nanofluid varied from 80 to 95g/s. The inlet temperature of the fluid in the radiator varied between 70-90°C, with intervals of 10°C. The results for the thermal conductivity showed a maximum relative increase of 1.7% at the concentration 0.002% at 25°C, whereas for the viscosity, a relative increase of 5.6% was observed at the concentration 0.003% at 85°C. A maximum relative increase of 3.6% was observed in the heat transfer rate of the nanofluid at a concentration of 0.003%, at 90g/s and 70°C. Related to the pressure drop, an average relative increase around 2% was observed for nanofluids in comparison with the base fluid.