4955
Rehab El-Sayed Abdel-Aziz Negida
PREPARATION AND INVESTIGATION OF SOME CERAMIC NANOFLUIDS FOR DIFFERENT APPLICATIONS
Nanofluids / titania, / zirconia / Zeta potential
Recently, it has been demonstrated that colloidal nanoparticles have many advantages and applications. These advantages are realized by controlling and manipulating the force between the suspended nanoparticles in the liquid. Nanofluids are dilute liquid suspentions of nanoparticles smaller than 100 nm. In this study, water-base ceramic nanofulids containing TiO2, Al2O3 and ZrO2 nanoparticles were prepared using ultrasonication method. Different amounts of suitable dispersant agent for each metal oxide nanofluids i.e. 0.1, 0.2, 0.3, 0.6, 1 and 1.5 wt.%, were tested to stabilize the prepared nanofluids. The stability of the prepared nanofluids was verified using optical microscope, transmission electron microscope and Zeta potential. After selecting the suitable amount of dispersant, nanofluids having different volume fractions of metal oxide nanoparticles were prepared e.g. 0.1, 0.15, 0.2, 0.5, 0.75 vol.%. The stabilized nanofluids were subjected for measuring rheological behavior and electrical conductivity. The measured electrical conductivity was correlated to the thermal conductivity according to Wiedemann-Franz law. The results revealed that the electrical conductivity increases with increasing particle concentration and reducing particle size. The influence of surfactant is found to increase the stability and decrease the electrical conductivity of the nanofluids by increasing its viscosity. There is a rise in electrical conductivity of nanofluids having low electrolyte concentration whereas a decrement is observed in nanofluids having high electrolyte concentration due to reduced surface conductance. Also, the rheological properties such as viscosity of nanofluids increased firstly with increasing shear rate thendecreased and increased with increasing particle concentration. The experimental observations on titania, alumina and zirconia nanofluids are compared to each other.
2015
M.Sc
Zagazig
Science