High-fidelity CFD simulations of pulsed sieve-plate extraction columns

The pulsed sieve-plate extraction column (PSEC) is a technology for liquid-liquid extraction processes widely used in various industries, and commonly employed in nuclear fuel reprocessing. A high fidelity computational fluid dynamic model of a solvent PSEC has been developed and run with single-phase water. The PSEC investigated consists of two perforated plate internals, operated under 1 Hz pulsing frequency, 20 mm amplitude and a plate spacing of 50 mm. The CFD used was based on unsteady flow calculations undertaken with a conventionally used RANS model, closed with the standard k-e turbulence model, and a large eddy simulation (LES). Results are compared with experimental data, where available, and agreement is improved by using the more accurate predictions of the turbulent flow in the column offered by large eddy simulation. Significant differences between predictions of the RANS and LES approaches are also found, drawing into question the usefulness of the former for predicting these complex flows. The CFD analysis brings useful insight into the hydrodynamics in PSECs, which provides better understanding for further work on both single- and two-phase flows in these devices.