A theoretical model describing bubble deformability and its effect on binary breakup in turbulent dispersions

This work addresses bubble deformability and binary breakup induced by turbulent fluctuations in liquid dispersion. In order to explore the dynamic process of bubble-eddy interaction, a theoretical model considering the surface deformation, is proposed through dimensional analysis in this work. Our model indicates that the bubble deformability depends on two key factors: the size ratio between the turbulent structure and the mother bubble, and the Weber number. Binary breakup of one single bubble is described through the degree of the surface deformation, and the effect of breakage constraints on it is investigated. It is found that equal-size breakage is dominated by the energy constraint, while most unequal-size breakage is dominated by the force constraint. The characteristic sizes of effective colliding eddies contributing to the bubble breakup process are computed based on the change of the surface energy. This work not only overcomes the sensitivity of the breakup models for turbulent dispersion systems to these parameters, but also gives good predication of bubble deformability in two-phase turbulent flow. (C) 2018 Elsevier Masson SAS. All rights reserved.