An experimental investigation of the flow and mass transfer behavior in a vertical aeration process with orifice ejector

Abstract

Vertical two-phase jets are widely used in environmental and industrial applications for their capacities to enhance fluid mixing, reaction and mass transfer rates. This paper presents an experimental investigation on the flow and mass transfer characteristics of vertical aeration process with the operational and design parameters of orifice ejector. The primary and suction flow rates, dissolved oxygen concentration and electric input power were measured, and a direct visualization technique with a high-speed camera was used to capture the image of the vertical two-phase jet. The experimental data were used to calculate the air volume fraction, specific input power, volumetric mass transfer coefficient and mass transfer efficiency. It was found that the air volume fraction and the mass transfer efficiency decreased with Reynolds number, whereas the input power and volumetric mass transfer coefficient increased. The air volume fraction, volumetric mass transfer coefficient and mass transfer efficiency were higher for the orifice ejector configuration with a smaller throat area ratio. The experimental data was used to propose empirical correlations to predict the volumetric mass transfer coefficient.