Parametric study of overall heat transfer coefficient of CuO/water nanofluids in a car radiator

In this research, the overall heat transfer coefficient of CuO/water nanofluids is investigated experimentally under laminar flow regime (100 <= Re <= 1000) in a car radiator. The experimental system is quite similar to cars' cooling system. The nanofluids in all the experiments have been stabilized with variation of pH and use of suitable surfactant. The results show that the overall heat transfer coefficient with nanofluid is more than the base fluid. The overall heat transfer coefficient increases with the enhancement in the nanofluid concentration from 0 to 0.4 vol.%. Conversely, the overall heat transfer coefficient decreases with increasing the nanofluid inlet temperature from 50 to 80 degrees C. The implementation of nanofluid increases the overall heat transfer coefficient up to 8% at nanofluid concentration of 0.4 vol.% in comparison with the base fluid. In addition, the results are statistically analyzed using Taguchi method by implementing Qualitek-4 software. The maximum value of the overall heat transfer coefficient with nanofluid, effect of each operating parameter on the overall heat transfer coefficient and the optimum values of each parameter are determined. (C) 2012 Elsevier Masson SAS. All rights reserved.