On the role of the macroscopic deformation in liquid film drainage between bubbles

Abstract

The collision of bubbles in multiphase reactors is critical to bubble size distribution. However, the theoretical models that can reasonably predict collision outcomes and the experimental data that can be used to directly verify the models are still very lacking. We studied the collision of two bubbles in clean water through experiments and theoretical modeling, revealing the mechanism that the collision result shifts from coalescence to rebound with increasing collision velocity. The macroscopic deformation (MacrD) of bubbles is associated with the film drainage via a segmented linear equation as a function of the film radius and initial Weber number. Thus, the current model can reflect the effect of MacrD in a self‐consistent way. The coalescence times and critical coalescence velocities predicted by the model were in good agreement with the experiments. This work provides novel insights into bubble coalescence modeling and serves to improve the accuracy of reactor simulations.

Polydisperse particle inline image method and its application onto gas–liquid flow in a stirred tank

“…For examples, on the mesoscale, bubbles frequently coalesce and break up through the interaction with liquid vortices or other bubbles. 9,10 On the reactor scale, it significantly accounts for the change in flow structure and flow regime. 11 Hence, it is of significance to deeply understand the polydisperse bubble hydrodynamics, to help modeling gas-liquid systems and consequently providing instructions for the design and scale-up of industrial gas-liquid reactors.…”

“…The coexistence of large and small bubbles in a bubble swarm results in more complex multiphase hydrodynamics. For examples, on the mesoscale, bubbles frequently coalesce and break up through the interaction with liquid vortices or other bubbles 9,10 . On the reactor scale, it significantly accounts for the change in flow structure and flow regime 11 .…”