Experiment and Simulation Study on the Effect of Internals in Gas–Liquid Bubble Columns with a Low Aspect Ratio

The gas–liquid flow dynamics in a special bubble column with a low aspect ratio, which was equipped with annular gas distributors, were investigated through experiments and computational fluid dynamics simulation. The local gas holdup in the empty column obtained by the fiber probe and pressure sensors was used to validate the accuracy of the numerical simulation. The effect of the number of internals that were arranged near the column wall on the flow characteristics was further studied. A unique core-annular liquid circulation (ascending in the annular region and descending in the core region) was found in this special bubble column. The increasing number of internals produced weaker turbulent dissipation rates and turbulent kinetic energy in the annular region, as well as greater shear stresses which forced the bubbles to prefer to diffuse to the other radial position. The influence of a larger number of internals could be considered to divide the bubble column into subcolumns.