Effect of bubble-to-oil size ratio on dynamic behavior in flotation

The successful flotation of micro-oil-bubble compounds to the liquid surface is essential for removing oil after bonding bubbles and oil droplets. Nevertheless, microbubble flotation is inherently unstable. This paper investigates the dynamic behavior of microbubbles and oil droplets utilizing the OpenFOAM software. The upwelling process and flotation behavior of bubbles and oil droplets at different oil-gas diameter ratios (L) are analyzed. And a comprehensive analysis of the effects of multiple factors on microbubble flotation results is established using the dimensionless numbers Eötvös (Eo), Weber (We) and L. This analysis is conducted to select conditions that promote the stability of microbubble flotation, and to obtain the optimal range of oil-gas diameter ratios that promote upwelling at different Eo and analyzes the underlying mechanism. When L>1.3 and 0.5<L≤1, the floating stability of micro-oil-bubble compounds is improved because buoyancy is the dominant force. While, in the range of 1<L≤1.3, the horizontal lifting force becomes dominant in floating and causes the wall attachment phenomenon to occur more frequently. Upon examination of the correlation between the diameter ratio and the We, it becomes evident that We increases as the diameter ratio approaches 1.