Bubbly Flows

The priority research ,,Analysis, Modelling and Numerical Calculations ofMul­ tiphase Flows" was running for 6 years (from 1996 to 2002) and financially sup­ ported by the Deutsche Forschungsgemeinschaft (DFG). The main objective ofthe research programme was to provide a better understanding of the physical basis for multiphase gas-liquid flows as they are found in numerous chemical and bio­ chemical reactors. The research comprised steady and unsteady multiphase flows in three frequently found reactor configurations, namely bubble columns without interiors, loop reactors, and aerated stirred vessels. For this purpose, new and im­ proved measurement techniques should be developed. From the resulting knowl­ edge and data, new and refined models for describing the underlying physical processes should result, which can be used for the establishment and improvement of analytic as well as numerical methods for predicting multiphase reactors. Thereby, the development, lay-out and scale-up ofsuch processes should be pos­ sible on a more reliable basis. For achieving this objective three research areas were defined: • development and improvement of experimental techniques which allow accu­ rate measurements in steady and unsteady multiphase flows • elaboration of new modelling approaches in order to describe the basic trans­ port processes for mass, momentum, and heat in bubbly flows • development of analytical and numerical methods supplemented by the new modelling strategies in order to support optimisation and lay-out of technical multiphase processes.