Hybrid Multiphase CFD Simulation for Interfacial Area Prediction in Liquid-Liquid Extraction

A hybrid multiphase CFD solver which combines the Euler-Euler multi-fluid method with VOF sharp interface capturing has been developed using the open-source package OpenFOAM® for application to liquid-liquid extraction devices such as annular centrifugal contactors. This solver (multiphaseEulerFoam) has been extended to enable prediction of mean droplet size and liquid–liquid interfacial area through a single moment population balance method. Simulations of liquid–liquid mixing and separation in a model annular centrifugal contactor are reported. We compare several common droplet breakup/coalescence models along with efforts to calibrate model parameters versus available experimental data. Quantitative comparison is made for two different housing vane geometries and it is found that the predicted droplet size is significantly smaller for vane geometries which result in higher annular liquid holdup. Comparison with experimental observations for similar systems will be discussed along with proposed efforts to extend the methodology to include interfacial mass transfer and enable prediction of overall stage extraction efficiency.