Gas-liquid flow in a rectangular bubble column was studied numerically using open source CFD code OpenFOAM. Eulerian-Eulerian approach was used to carry out the time-dependent motion of the liquid driven by gas bubbles injected at the bottom of the column through a local sparger. The incompressible two-fluid flow solver, “twoPhaseEulerFoam” (Euler-Euler type) has been developed and implemented in an open source CFD code OpenFOAM with new interfacial closures (drag and lift models), κ-ε turbulence model and modified mass and momentum equations. The two-fluid model has further been extended to implement multi-fluid model (multiPhaseEulerFoam) to understand the predictive capabilities of both the models. Size dependent drag and lift models have been studied to understand the hydrodynamics for different size group bubbles. Considering the inherently unsteady nature of the gas-liquid flows in bubble columns, three-dimensional unsteady simulations were performed in OpenFOAM to predict the dynamic and time-averaged characteristics and the predictions were compared with the available experimental results. The results of two-fluid and multi-fluid models were compared in terms of drag/lift forces on dynamic characteristics, time-averaged gas volume fraction and liquid velocity profiles.

Keywords: OpenFOAM, Bubble column, CFD, Drag-lift, Gas-liquid flow.