CFD simulation of bubble column flows: An explicit algebraic Reynolds stress model approach

CFD study of flow hydrodynamics has been conducted in transient Euler-Euler environment by using commercial simulation software Ansys CFX 14.0. First, three different wall lubrication force models are compared. Afterwards, the influence of turbulent dispersion force models has been analyzed. Finally, the performance of Explicit Algebraic Reynolds Stress Model (EARSM) combined with k-ε and Baseline (BSL) models has been tested. Three different combinations of EARSM were included with two cases incorporating the Bubble Induced Turbulence (BIT) as well (i.e. EARSM k-ε BIT, EARSM BSL, EARSM BSL BIT). All simulations were compared for average velocity and turbulent kinetic energy profiles with experiments. The performance of these models was also compared with Re-Normalization Group (RNG) and k-ε models. EARSM k-ε model was unable to capture the axial liquid as well as gas phase velocities close to experimental values. On contrary, EARSM BSL and EARSM BSL BIT were more successful in predicting the velocity profiles and showed good agreement with experiments, with EARSM BSL slightly less accurate in predicting axial velocity profiles. All models predicted the turbulent kinetic energy profiles reasonably good both quantitatively as well as qualitatively, while near the bottom of the column; EARSM k-ε slightly under predicted the turbulent quantities. Thus, EARSM combined with BSL and BIT can be effectively exploited for simulating flow fields and turbulent quantities.