Computational Fluid Dynamics for energy efficient multiphase flow processes

Multiphase flows are frequently applied in industrial processes as e.g. in chemical engineering. Reliable predictions of the flow characteristics such as local concentration of species and interfacial area density in gas-liquid flows can contribute to an optimization of the design of corresponding apparatuses and processes. Due to the high energy consumption of such process there is a considerable potential to save energy and materials. Computational Fluid Dynamics (CFD) in principle allows the simulation of such flows and provides local flow characteristics. While it is frequently used for industrial problems in case of single phase flows it is not yet mature for two-phase flows. The reason is the complex gas-liquid interface. For medium and large scale flow domains it is not feasible to resolve all details of this interface. Averaging procedures have to be applied and in most cases the so-called two- or multi-fluid approach is used. It assumes interpenetrating phases and the information on the interface gets lost by these averaging procedures. This information has to be added to the basic balance equations by so-called closure models. The development and validation of such models is done at Helmholtz-Zentrum Dresden – Rossendorf (HZDR) to obtain tools for reliable predictions of multiphase flow characteristics in medium and large industrial scales.