Experimental investigation of dynamic viscosity of water-based nanofluids containing tungsten oxide-multi-walled carbon nanotubes-zirconium oxide nanoparticles at mono and hybrid conditions

Recently, a great deal of study was done on the rheological characteristics and heat transfer of nanofluids (NFs). This study investigated how temperature and solid volume fraction (SVF) parameters affected the dynamic viscosity of water hybrid nanofluids (HNF), and zirconium oxide (ZrO2)-tungsten oxide (WO3)-MWCNTs (MWCNTs). Binary HNF combinations of MWCNTs-WO3/water, MCWCNTs-ZrO2/water, and WO3-ZrO2/water were examined, in addition to WO3/water mono-nucleids (MNFs), MWCNTs/water, and ZrO2/water. NFs were prepared by a two-step method and ultrasonic waves were used to stabilize NFs. Ternary HNF was tested in the SVF = 0.1 to 0.6% and the temperature range of 20 to 60 degrees C. The stability of NFs was examined using both the photographic technique and the zeta potential test, with the findings indicating that the quality of NFs is satisfactory. Brookfield viscometer was used to measure dynamic viscosity. The attained results indicated that dynamic viscosity declines in all SVFs by rising temperature and dynamic viscosity rises in all temperatures, along with rising SVF. The viscosity of a hybrid nanofluid containing SiO2, MWCNTs, and WO3 in water at SVF ranging from 0.2% to 0.6% and temperatures between 20 and 60 degrees C decreased by increasing temperature across all volume fractions. The results showed that, at a 0.2% volume fraction, viscosity decreased from 2.47 to 1.07 cP, and at 0.3%, a 57% reduction from 2.93 to 1.26 cP was observed. Similar reductions were reported for higher volume fractions (0.4% to 0.6%). Finally, to evaluate the viscosity of tested NF, a mathematical model was proposed. The results, which were attained from the presented model, showed an excellent consistency with the experiment rates.