Aspect ratio of bubbles in different liquid media: a novel correlation

The bubble shape is a required parameter in the modeling and design of multiphase reactors. This communication contributes to the broader discussion and closes the knowledge gap by providing a practical correlation for the bubble shape. The correlation is based on a very large experimental dataset, encompassing a wide range of Morton numbers (Log₁₀(Mo) in the range of −10.8 and 2.3), flow conditions (single bubbles and dense bubbly flows) and considering both gravity-driven flows and flows with an extra-external pressure gradient (counter-current flows). The experimental data were post-processed to derive a simple and physics-based correlation, relating the bubble aspect ratio to the bubble Reynolds and Eötvös numbers. This correlation provides a more accurate description and covers a wider range of applicability compared with literature correlations. As such, it can be helpful in the estimation of the interfacial area and velocity of a dispersed phase rising in a continuous phase.