Abstract The efficiency of industrial multiphase reactors is fundamentally constrained by millimeter‐sized bubbles easily coalescing into centimeter‐sized bubbles. In this study, we observe a coalescence‐inhibited dense bubble swarm (CIDS) (the local gas volume fraction ε exceeds 30%) with millimeter‐sized bubbles (ca. 5 mm) in ultrapure water. The flow regime of CIDS remains homogeneous even under high ε , while under common conditions it is heterogeneous. Compared with common bubble swarms, CIDS achieves at most an 185% increase in overall ε , a 723% increase in local ε in the downcomer, a 216% increase in mass transfer area, and a 252% increase in volumetric mass transfer coefficient. For CIDS, friction generated by the gas through the ultra‐microporous (<5 μm) ceramic membrane increases the repulsive force, inhibiting bubble coalescence. Finally, a correlation of the bubble size is established based on the orifice Weber and Reynolds numbers, with an average error of 3.86%.
Gu et al. (Fri,) studied this question.