CFD-PBM Coupled Simulation of an Airlift Reactor with Non-Newtonian Fluid

Abstract

-Hydrodynamics of an AirLift Reactor (ALR) with tap water and non-Newtonian fluid was studied experimentally and by numerical simulations. The Population Balance Model (PBM) with multiple breakup and coalescence mechanisms was used to describe bubble size characteristics in the ALR. The interphase forces for closing the two-fluid model were formulated by considering the effect of Bubble Size Distribution (BSD). The BSD in the ALR obtained from the coupled Computational Fluid Dynamics (CFD)-PBM model was validated against results from digital imaging measurements. The simulated velocity fields of both the gas and liquid phases were compared to measured fields obtained with Particle Image Velocimetry (PIV). The simulated results show different velocity field profile features at the top of the ALR between tap water and nonNewtonian fluid, which are in agreement with experiments. In addition, good agreement between simulations and experiments was obtained in terms of overall gas holdup and bubble Sauter mean diameter. NOMENCLATURE SymbolsVolume fraction of gas/liquid phase, 1 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Bubble size distribution and gas holdup in bubble columns employing non‐Newtonian liquids: A CFD study

“…[ 23 ] Moreover, the characteristic bimodal BSD observed at higher due to the presence of a larger range of bubbles is evident at 0.15 and 0.20 ms −1 . A similar observation was also confirmed by Han et al [ 25 ] using CMC.…”

“…The higher rise velocity of larger bubbles reduced the gas residence time, thereby reducing gas holdup. The CFD study by Han et al [ 25 ] showed a bimodal BSD in aqueous CMC with an increase in . The BSD changes from uniform, narrow, and monomodal to bimodal having large bubbles in the heterogeneous regime.…”

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“…Rheology issues were widely discussed throughout the conference [7], as was the development of new interfacial rheologytechniques [8]. Finally, multiphase flow modeling is obviously another major issue for the development of innovative techniques [7,9].…”