Forced convection heat transfer and friction factor of water/bio-glycol mixture based TiO2-SiO2 nanofluids

Abstract

The research on nanofluids as heat transfer fluid has been done for many years and the manipulation of nanoparticles kept evolving as time passes by. After an exceptional heat transfer performance enhancement was found in single nanofluids, combining two types of nanoparticles in a base fluid has garnered researcher’s attention all over the globe. The study on performance of heat transfer for a combination of two types of nanoparticle in a mixture of water and Bio-glycol has yet to be established; hence, the present study was conducted to investigate the heat transfer performance of TiO2-SiO2 nanofluids in 60:40 mixture of water and Bio-Glycol. The TiO2-SiO2 nanofluids was prepared by using the two-step method at three different particle concentration, namely 0.5%, 1.0% and 1.5%. Forced convection heat transfer experiment was carried out at bulk temperature 30°C and Reynolds number in the range of 1000 to 8000. A constant heat flux was supplied to the test section throughout the experiment. The Nusselt number of TiO2-SiO2 nanofluids was found at particle concentration 1.5%, 70.11% enhanced from the base fluid. The average enhancement of heat transfer coefficient for each particle concentration 0.5%, 1.0% and 1.5% are 40.3%, 63.4% and 70.3%, respectively. Heat transfer coefficient enhancement for 1.0% and 1.5% particle concentration almost similar at low concentration, however, as Reynolds number increase, the augmentation gap increases. The results of friction factor displayed a decrease trend with the increase of Reynolds number. While the friction factor of TiO2-SiO2 nanofluids insignificantly increased from the base fluid, the increment between particles concentration almost negligible.