Evaluation of Computational Models for Simulations of Multiperforated Bubble Column

Abstract

Bubble columns are widely used in industrial applications due to their simple construction and operation. Plates are often placed inside the bubble column to generate bubbles and enhance mixing efficiency. Transient gas-liquid flows in partially aerated bubble columns were simulated using an Eulerian-Eulerian based large eddy simulation approach. In this study, perforated plates in 3×3, 5×5 and 7×7 arrangements were considered. The characteristics of flow dynamics, spectra induced by air flow passing through perforated plates into a stagnant bubble column and global gas holdup were investigated. Effects of multiperforation simulation techniques, namely full and quarter flow domain setups were also examined. It was observed that using quarter flow domain simulation strategy could introduce unrealistic physical artefacts in the numerical results. Numerical data showed the presence of the classic -5/3 law of power spectrum density for the vertical liquid velocity in the low frequency region (<10 Hz) while a faster decay was found in the high frequency region (> 10Hz). The global gas holdup was found to decrease with increased perforation array size.