A Combined Multifluid-Population Balance Model Applied to Dispersed Gas–Liquid Flows

Abstract

The two-phase bubble columns are widely used for carrying out gas–liquid reactions in a variety of industrial applications. The optimal operation of many of the processes carried out in the bubble columns depends on the bubble size distribution, which determines the interfacial momentum, mass, and heat transfer fluxes through the contact area between the liquid and gas phases. In this context, the population balance equation is relevant as it can be used to quantify the amount of bubbles of different sizes present at different locations in the bubble column. The combined multifluid-population balance models use mass and momentum equations coupled with population balances for the dispersed phase, whereas the continuum mechanical equations of the two-fluid or multifluid models are used for the liquid phase. The most rigorous description is based on a kinetic theory approach with size resolution (KTAWSR). In this study, the KTAWSR model is applied to simulate bubbly flows under complex conditions, that is, significant change in the Sauter mean diameter along the axial direction of the bubble column. The model is solved using the spectral orthogonal collocation method. Both sensitivity analyzes and comparison to experimental data from the literature are used to assess the potential of the model. Fair agreement between the experimental data and model prediction is achieved. It is concluded that the model adds as a valuable tool with good potentials for the population balance community, considering both the level of details resolved with this model and its possible use in developing future breakage and coalescence models.