Influence of Venturi Tube Geometry and Particle Properties on the Hydrodynamic Cavitation for Fine Particle Flotation

Abstract

In this study, the influences of both Venturi tube geometry and particle properties on the hydrodynamic cavitation are investigated. In the geometry study, we investigated numerically and experimentally the influence of several geometrical parameters on the cavitation inception and bubble generation. Using a dimensionless number analysis, an inverse relation is found between the cavitation inception and the single-phase flow resistance set by the geometry. In the cavitation regime, the flow resistance induced by cavitation follows a single trend regardless of the studied geometries. The small outlet angle associated with low inception velocity was found to be favorable for cavitation activities. Moreover, the amount of bubbles generated was found to be correlated to extra flow resistance induced by the cavitation process and the dissolved gas concentration. The insights gained in this study provided a guideline to design efficient Venturi tube in regard to the cavitation process for fine particle flotation. In industrial applications in mineral processing, fluid under hydrodynamic cavitation has large amount of particle content with different properties. In this work, the changes in cavitation behavior were examined with the particles of different surface properties. The results were quantified by dimensionless number method developed in the geometry study. In comparison with water, the hydrophobic particles were found to be favorable for cavitation. Finally, the significant drop in cavitation inception velocity with bubble injection was observed by using the existing equipment and experimental methods.