Model development for simulating bubble breakup in gas-liquid bubbly flows with the Eulerian-Lagrangian approach
The Eulerian-Lagrangian method has been widely used to simulate the flow pattern,bubble size(or gas holdup)and its distribution in gas-liquid reactors.However,this method reported in literature is mainly based on the critical Weber number viewpoint to describe the bubble breaking behavior,and the size of the broken sub-bubbles is determined by random numbers.The existing experimental and theoretical studies have shown that the viewpoint of critical Weber number cannot reflect the influence of physical parameters(e.g.gas density)such as gas density and gas redistribution within the bubble on bubble breakup behavior.In view of above shortcomings,this paper proposes a new bubble breakup model suitable for the Eulerian-Lagrangian framework that considers the contribution of gas redistribution mechanism,and develops a solver based on this new model on the basis of open-source software OpenFOAM.The model predictions are in good agreement with the measured time-averaged axial liquid velocity and bubble size distributions.Particularly,the proposed model considering gas redistribution mechanism successfully predicts the bimodal distribution characteristic of bubble size distribution observed in the experiments.