Droplet breakage and coalescence in liquid–liquid dispersions: Comparison of different kernels with EQMOM and QMOM

Abstract

Droplet coalescence and breakage in turbulent liquid–liquid dispersions is simulated by using computational fluid dynamics (CFD) and population balance modeling. The multifractal (MF) formalism that takes into account internal intermittency was here used for the first time to describe breakage and coalescence in a surfactant‐free dispersion. The log‐normal Extended Quadrature Method of Moments (EQMOM) was for the first time coupled with a CFD multiphase solver. To assess the accuracy of the model, predictions are compared with experiments and other models (i.e., Coulalogou and Tavlarides kernels and Quadrature Method of Moments [QMOM]). EQMOM and QMOM resulted in similar predictions, but EQMOM provides a continuous reconstruction of the droplet‐size distribution. Transient predictions obtained with the MF kernels result in a better agreement with the experiments. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2293–2311, 2017

Modelling of Bubbly Flow Using CFD-PBM Solver in OpenFOAM: Study of Local Population Balance Models and Extended Quadrature Method of Moments Applications

“…QMOM and EQMOM have been recently compared in the study of liquid-liquid dispersion in a stirred tank [33,37]. Li et al [37] performed a comparison between QMOM and EQMOM in turbulent liquid-liquid dispersion, and they observed that these two methods provided similar predictions.…”

“…While this reconstruction is not unique for the set of transported moments, examining the reconstructed NDF can provide a better insight into the behavior of the dispersed phase. In order to plot NDF, weights and abscissae calculated by EQMOM and extracted from CFD-PBM solver are utilized to approximate Equation (37). Figure 4 indicates the shape of NDF in the liquid phase (water zone) at t = 60 s. It can be observed that the mean bubble diameter ranges from 1 mm to 6 mm, and thus, the monodispersity is not a suitable approximation.…”

“…Li et al [37] performed a comparison between QMOM and EQMOM in turbulent liquid-liquid dispersion, and they observed that these two methods provided similar predictions. They managed to reconstruct the droplet size distribution by using EQMOM.…”

Application of extended quadrature method of moments for simulation of bubbly flow and mass transfer in gas‐liquid stirred tanks

“…Their model predictions were validated against experimental data. Li et al compared EQMOM with QMOM in a turbulent liquid‐liquid mixing and they found these two approaches make similar predictions. They performed reconstruction of the droplet size distribution with the use of EQMOM.…”

A study on liquid‐liquid dispersions in a continuous mixer via computational fluid dynamics (CFD) simulation combined with population balance model (PBM)

“…To predict the evolution of DSD, the two‐fluid model coupled with a breakage and coalescence model have been adopted in the literature . The multifractal kernel model was successfully applied to predict the liquid‐liquid dispersions in stirred tanks by Li et al and Gao et al…”