On Inter-bubble Hydrodynamics and Cluster Formation in Non-Newtonian Bubbly Columns: A Review

A comprehensive understanding of the inter-bubble dynamics and the cluster formations in non-Newtonian fluids is pivotal for chemical and biomedical engineering applications. In this review, we summarize current research efforts to provide a fundamental understanding and engineering principles of the interactions between bubbles and the dynamics of bubble clusters in non-Newtonian fluids. Although the majority of research is still predominantly conducted through experimentation, the significance of computational fluid dynamics in elucidating interaction mechanisms has become increasingly prominent in recent years. Moreover, the gas-liquid systems reviewed in this paper are driven by gravity, which is closer to the actual industrial processes. We indicate the effects of non-Newtonian fluid special rheological properties (especially viscoelasticity and shear-dependent viscosity) on the interaction between multiple bubbles and the formation of clusters. We summarize the main empirical correlations in related research, which are useful for the optimization of industry. Ultimately, we address the current trends, limitations, and future directions in this research field.