Gases have to be specifically mixed with a continuous liquid phase to perform a reaction with high yield and selectivity. The time scales of mixing are determined by the transport processes in the boundary layer close to the phase boundary and by bubble swarm turbulence. For clarification of the local mass transfer in bubbly flows, an experimental setup is developed and successfully used to investigate single rectilinear (spherical), helical (ellipsoid) and irregular rising bubbles with and without chemical reaction. Therefore, the time resolved scanning laser induced fluorescence technique is further developed and applied for the first time to bubbly flows to allow new insights in the mass transfer processes.
