New Phenomena of Mass Transfer in Gas/Liquid Flows

Abstract

Abstract Due to a lack of knowledge of mass transfer in multiphase flows, investigation into mass transfer is in great demand in order to obtain a better understanding of local phenomena. This paper describes the experimental investigation into mass transfer, in particular the influence of flow conditions around bubbles, contact time between phases, bubble size and viscosity of the liquid. Single bubbles are injected into a bubble column (diameter dR = 100 mm). The laser-induced fluorescence measuring technique (LIF) is used to visualize the concentration field around a freely rising bubble. A special experimental set-up has been developed which permits a three-dimensional (3d) reconstruction of the local concentration field around bubbles. Oxygen concentration fields of ellipsoid gas bubbles with equivalent diameters between 4mm and 8mm in aqueous solutions are shown and local mass flows are presented.