Modelling of breakage rate and bubble size distribution in bubble columns accounting for bubble shape variations

摘要

In the study of meso-scale structures of multi-phase flow in bubble columns, accurate modelling of the interaction between the turbulence eddies and particle/bubble groups is crucial for capturing the heat and mass transfer occurring between the bubbles and surrounding carrier fluid. This work focuses on the influence of bubble shape variations on bubble breakage due to the eddy collision with the bubbles in bubble column flows. An improved breakage model accounting for the variation of bubble shapes was proposed. The improved breakage model coupled with the widely adopted isotropic, homogeneous turbulence kinetic energy spectrums, that are currently available from the open literature, takes into account the different energy requirements in forming the daughter bubbles, i.e. the increase of in surface energy and the pressure head difference of the bubble and its surrounding turbulent eddies. The simulation results compared with experimental data have clearly demonstrated that the improved model effectively describes the various shapes of bubble breakage events, which may consequently have a strong impact on the interfacial area estimation that is crucial for calculation of the transfer rates of mass and heat transfer in the bubble columns. (C) 2018 Elsevier Ltd. All rights reserved.