SMM - Multi-Scale Modelling of Multiphase Flows

The main topic of the research chair on Multi-Scale Modelling of Multiphase Flows is the development of advanced reactor models for multiphase reactors with industrial relevance. At present our research focuses on the hydrodynamics in these reactors because it is generally recognized that the lack of understanding of the flow phenomena is one of the central difficulties in the design and scale-up of multiphase reactors. In the near future the interplay of flow phenomena with chemical reactions will be studied in great detail.
We use various types of computational fluid dynamics (CFD) models (both commercial codes but mostly “in house” made codes) to study the hydrodynamic phenomena at all relevant length and time scales, i.e. at the microscopic, mesoscopic and macroscopic scale. In our group both multi-fluid models are being developed and deterministic and stochastic models which treat the dispersed phase (particles, bubbles or droplets) in a discrete manner accounting for possible encounters between the dispersed elements. Furthermore, we develop various direct numerical simulation (DNS) models that account for the interfacial interaction without any prior assumptions. The latter can be used to provide closure information for the multi-fluid or discrete models.

The described area is strongly related to our development of advanced experimental techniques to measure key quantities (i.e. local volume fractions, temperature distributions, and velocities of the dispersed and continuous phase). For example we developed a digital particle image velocimetry technique to measure the velocity maps of both the liquid phase and dispersed gas bubbles in (dense) gas-liquid dispersions with the aid of high speed cameras (1000 frames per second). This type of flow very often arises in a variety of gas-liquid contactors/reactors.