Evaluation of gas-lift effect by bubbles rising in a vertical circular pipe

Abstract

The gas-lift effect appears in various types of gas-liquid two-phase flows. Information on the effect in a still liquid however is very limited compared to that in a moving liquid. Experiments were carried out in this study on the case that air bubbles rose in sill water contained in a vertical circular pipe made of transparent acrylic resin. The flow pattern covered bubbly and slug flow regimes. The effect is composed of bath surface elevation effect and liquid flow induction effect. The latter effect was quantitatively evaluated in terms of the pipe friction loss in the pipe. An empirical equation on an apparent frictional coefficient was proposed for predicting the loss. The experimental results reveal that the liquid flow induction effect is weak in the bubbly flow regime, while prevails significantly in the slug flow regime.

Keywords

• two-phase flow
• gas-lift effect
• void fraction
• frictional loss
• apparent kinematic viscosity