Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The qualification of Computational Fluid Dynamics (CFD) codes for two-phase flows is an important topic in the frame of German CFD initiative initiated by the Gesellschaft für Anlagen- und Reaktorsicherheit (GRS). This concerted action especially aims on phenomena in the primary system of light water reactors. Forschungszentrum Dresden-Rossendorf e.V. (FZD) is involved in both – the generation of CFD-grade databases and CFD model development and validation. The data obtained in our TOPFLOW experiments clearly show a separation of small and large bubbles over the pipe radius due to the action of the lateral lift force. This has a considerable influence on the local interfacial area density. Also the other bubble forces as drag and turbulent dispersion force clearly depend on the bubble size. For this reason it is important to introduce bubble size dependent velocities fields in a proper modeling of poly-dispersed flows.