Regime transition in bubble columns: experimental and predictions

The present paper examines the effects of sparger design and dispersion height on the regime transition. Experiments were performed in a 0.385 m i.d. bubble column. Twenty-two designs of sieve plate spargers were employed. Free area was varied in the range of 0.136-5.0% and the hole diameter was varied in the range of 0.8-50 mm. The height to diameter ratio was varied in the range of 1-8. The effect of coalescing nature of the liquid phase was also investigated. In order to reduce the coalescing behavior as compared to air-water system, aqueous solution of 0.2 M NaCl formed the liquid phase. For enhancing the coalescing behavior, the liquid phase was 1% (w/w) solution of carboxy methyl cellulose. A mathematical model has been developed for the prediction of critical gas hold-up on the basis of linear stability analysis. A comparison has been presented between the model prediction and the experimental observations. (C) 2003 Elsevier Inc. All rights reserved.