Liquid mixing based on convection and turbulent dispersion in bubble columns

A phenomenological model for liquid mixing, that captures the essence of the observed physical phenomena in bubble columns, is presented. In this model, mixing of the liquid phase is considered to be primarily due to convective recirculation and turbulence caused by the rising gas bubbles. The mixing phenomena is thus linked with the hydrodynamics of the flow. The input parameters of the model are obtained using noninvasive experimental techniques, such as Computer Automated Radioactive Particle Tracking (CARPT) and Computer assisted Tomography (CT) to measure the local liquid velocities and void fraction distribution in the system. In addition, it is shown that model parameters can be related to the turbulent eddy diffusivity measurements obtained by CARPT. The model is shown to compare well with tracer data and to reflect a variety of experimental observations. A brief comparison with the axial dispersion model (ADM) and recycle with cross-flow (RCF) model is presented.