Hybrid nanofluids based on Al2O3, TiO2 and SiO2: Numerical evaluation of different approaches

• Published in: International journal of heat and mass transfer 2017-01, Vol.104, p.852-860
• Main Author: Minea, Alina Adriana
• Format: Article
• Language: English
• Subjects: Heat transfer; Hybrid nanofluids; Oxide nanoparticle; Thermal conductivity; Viscosity
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2016.09.012

•A numerical evaluation of three oxide based nanofluids and their hybrids is proposed.•Thermal conductivity is increasing by at least 12%.•The viscosity uncertainty when using theoretical or experimental correlations was found to be very important.•New Nu correlation for alumina nanofluids and their hybrids was developed. Thermo physical properties of the nanofluids are quite essential to predict their heat transfer behavior. In this article a numerical evaluation of three oxide based nanofluids and their hybrids is proposed. It was noticed that all the nanofluids thermophysical properties are varying with the addition of nanoparticles and thermal conductivity is increasing by at least 12%. In addition, the uncertainty in viscosity estimation when using theoretical or experimental correlations was found to be very important. In regard to viscosity of hybrid nanofluids, one can notice that the HS and HT series have lower viscosity than MHT and MHS series. This discrepancy appears because of the method of calculation, as was noticed also for the alumina nanofluids. Moreover, a new Nu correlation for alumina nanofluids and their hybrids was developed. This new equation is a function of the Reynolds number, Prandtl number, and nanoparticle concentration.