16 research outputs found
Stability and electrical conductivity of water-base Al2O3 nanofluids for different applications
In this study, Al2O3âH2O nanofluids were synthesized using sodium dodecylbenzenesulfonate (SDBS) dispersant agent by ultra-sonication method. Different amounts of SDBS i.e. 0.1, 0.2, 0.3, 0.6, 1 and 1.5Â wt.% were tested to stabilize the prepared nanofluids. The stability of nanofluids was verified using optical microscope, transmission electron microscope and Zeta potential. After selecting the suitable amount of dispersant, nanofluids with different volume fractions of Al2O3 were prepared. Zeta potential measurement of nanofluids with low alumina and intermediate fractions showed good dispersion of Al2O3 nanoparticles in water, but nanofluids with high mass fraction were easier to aggregate. The stabilized nanofluids were subjected for measuring of rheological behavior and electrical conductivity. The electrical conductivity was correlated to the thermal conductivity according to WiedemannâFranz law. The results revealed that the nanofluid containing 1% SDBS was the most stable one and settling was observed for the fluid contained 0.75Â vol.% of Al2O3 nanoparticles which gave higher viscosity. The rheological measurements indicated that the viscosity of nanofluids decreased firstly with increasing shear rate (shear thinning behavior). Addition of nanoparticles into the base liquid enhanced the electrical conductivity up to 0.2Â vol.% of Al2O3 nano-particles after which it decreased