An evaluation of the horizontal injection microbubble generator

Abstract

The use of microbubbles has grown immensely in many fields such as the petrochemical industry and in wastewater treatment. This phenomenon offers a number of advantages that include the ability to provide larger liquid-gas surface contact areas. In addition, in shallow aeration conditions horizontal injection is preferred in order to increase the contact surface area and aeration time, thereby increasing the mass transfer rate. In this study, the orifice type of microbubble generator was set on a rectangular transparent glass box to support visualization. A set of experiments were specifically conducted in order to reveal the effects of varying both the water and air flow rate on the bubble diameter distribution and volumetric mass transfer coefficient. The bubble diameter was measured using image processing method, and the volumetric mass transfer coefficient was measured using the dynamic method. The results showed that increases to the flow rate of water produced smaller bubble diameters, and a more homogeneous bubble diameter distribution. Furthermore, it was apparent that the water flow rate had a more significant effect on changes to volumetric mass transfer coefficient, compared to the air flow rate.