Influence of the Water Nature on the Two-phase Flow in an Air-lift Column

Abstract

The aim of this study is to determine the phase indicator functions of a two-phase flow in an air-lift vacuum column. The outcome of this study is to master the hydrodynamics in a vertical column when determining the size, the velocities of the bubbles and the void rate then the gas-liquid interphase. The functions are the vacuum rate, the interface speed and bubble size, the flow rate and the speed of the liquid phase. The vacuum lift air column that is the subject of this study is based on the principle of air lift and flotation, all under vacuum. In its operation, the column combines hydraulic pumping, solute transfer and particle phase separation functions, which has the particularity of minimizing energy costs. The process of air-lift columns under the vacuum is still at the development stage and the experimental study of its hydrodynamics is one of the determining axes in the course of the exploration with a assessment to optimizing its design and functioning. The experiments were carried out on a vertical column composed of two concentric plexiglas tubes connected to a water recirculation tank and to a vacuum pump. For all experiments performed, demineralized water and salt water are used and the flow rate is measured using a flow meter. The experimental analysis is done using two-phase instrumentation consisting of a bi-probe and the use of experimental techniques has enabled a better understanding of the hydrodynamics of the two-phase flow.