Improving mass transfer coefficient prediction in bubbling columns via sphericity measurements

The prediction of the oxygen transfer coefficients (k(L)) in bubbling columns is studied. Bubbling columns have important applications as bioreactors. It is found that the coefficient is strongly influenced by the motion and geometric characteristics of the bubbles. In the experiments, it is observed that the maximum transfer coefficient is achieved when a measure of the bubble sphericity reaches a minimum and the slip velocity a maximum. The introduction of characteristic parameters to account for the bubble deformation is proposed. Their use greatly improves the prediction of the oxygen transfer coefficient using standard correlations.