A novel generalized multifluid modelling approach for the simulation of multiphase flows: application to intensified liquid-liquid extraction

Intensified liquid-liquid extraction is a separation process found in several applications in different industries including nuclear power generation, metallurgy and biotechnology. The multiphase hydrodynamic behaviour typical of intensified liquid-liquid extraction processes often exhibits a broad range of interfacial scales, ranging from small droplets embedded in a continuous phase to large interfaces observed in the segregated flow regions. This precludes the application of standard off-the-shelf multiphase modelling approaches, which rely on the assumption of either dispersed or segregated flow regimes in the entire computational domain, for the simulation of such flows. A novel GEneralized Multifluid Modelling Approach (GEMMA) has been developed and validated to allow for the simulation of such multiscale multiphase flows. In this work this approach is applied to the simulation of the hydrodynamic behaviour for acetone absorption in a rotating disc column. It is shown that the modelling approach can accurately predict key hydrodynamic parameters such as organic phase hold-up and mean Sauter diameter. In addition, the GEMMA approach allows for an adequate representation of both the finely dispersed flow observed in the active part of the column and of the large segregated interface present in the top separator. It is concluded that the proposed approach represents a promising tool for the simulation of complex multiscale multiphase flows such as those observed in intensified liquid-liquid extraction processes.