Experiments and fully transient coupled CFD-PBM 3D flow simulations of disperse liquid-liquid flow in a baffled stirred tank. (18th May 2022)

• Record Type: Journal Article
• Authors: Rave, Kevin; Hermes, Mario; Wirz, Dominic; Hundshagen, Markus; Friebel, Anne; von Harbou, Erik; Bart, Hans-Jörg; Skoda, Romuald
• Is Part Of: Chemical engineering science. Volume 253(2022)
• Publication Date: 2022-05-18
• Subjects: Fully transient coupled CFD-PBM -- Shadowgraphic droplet size measurements -- OpenFOAM -- Rushton turbine -- Baffled stirred tank; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2022.117518
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: Inline shadowgraphic droplet size measurements at multiple locations in the tank. Kernel parameters can be fitted to match the measured droplet size. Macro-instabilities are captured in the simulation. Droplet size trends over multiple operation points are captured. Trends are explained analyzing the time scales of breakup, coalescence and mixing. Abstract: Liquid-liquid disperse multiphase flow in a baffled tank stirred by a Rushton turbine is investigated by experiments and 3D simulations for different impeller speeds and volume fractions. Droplet size distributions are experimentally measured with an inline shadowgraphic probe and compared with fully transient coupled CFD-PBM simulations using the Eulerian multi-fluid framework, the inhomogeneous Multiple Size Group approach and a statistical turbulence model. The simulation model is assessed by a variation of size class and velocity group numbers, grid resolution and simulation domain extent. The model parameters for the breakup and coalescence kernels are fitted to match the measured droplet size distribution at a selected operation point. A subsequent application to different operation points shows that experimental droplet size trends are captured, albeit aside from the fitting point, deviations to data increase. The resulting droplet size distribution is analyzed by an assessment of the turbulent mixing, breakup and coalescence time scales.