CFD Simulation of RTD and Mixing in the Annular Region of a Taylor-Couette Contactor

Flow between two concentric cylinders, with either or both of them rotating, has potential advantages over the conventional process equipment. This flow, also termed as Taylor-Couette flow, which reveals a variety of flow regimes, is studied using computational fluid dynamics (CFD) simulations. The vortex motion causes mixing in the annulus, which necessitates the understanding of residence time of the fluid in the annulus and the mixing time. A systematic study of residence time distribution (RTD) and the mixing phenomenon in the annular region of the Taylor-Couette contactor has been carried out. The RTD predictions have been found to be in good agreement with the established experimental results. Axial dispersion in the Taylor vortex regime and the turbulent regime has been predicted, and it can be said that, with an increase in the radial mixing, the effect of velocity profile on the dispersion parameter significantly reduces at higher rotational speeds. Effect of axial flow, annular gap width, and rotational speed has been investigated on the axial dispersion. The dispersion number and the dispersion coefficient have been predicted.