Study of Sedimentation Process in Nanofluids with Various Concentrations of SiO2 and Al2O3 Nanoparticles

Abstract

This work focuses on the preparation of nanoliquids with application of nanoparticles in order to study sedimentation processes in suspensions chosen. Nanoliquids on the basis of SiO₂ and Al₂O₃ nanoparticles with sizes of 50 nm are prepared at their various concentrations using water as a basic liquid. The sedimentation process of the suspension in a steady state and for a long time has been monitored. In accordance with preliminary tests, sedimentation in SiO₂-based nanoliquids is slower than that in nanoliquids on the basis of Al₂O₃ nanoparticles. The monitoring for 72 h of sedimentation of nanoliquids prepared using a two-step method with application of two types of SiO₂ nanoparticles with sizes of 12 nm and 16 nm, as well as Al₂O₃ with a size of 50 nm, reveals that sedimentation and agglomeration processes in the considered nanoliquids depend to a large extent on the size and concentration of nanoparticles. The optimal sizes of particles and their concentrations in the suspension result in a very weak sedimentation.