Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The multi-fluid CFD methodology is widely used in the simulation of multiphase flows. The numerical results are able to provide insight and knowledge on local phenomena, and frequently used to assist the design, optimization and safety analysis of industrial processes. However, current multi-fluid CFD simulations often suffer from two limitations. One is that the predictability for multiphase systems is not fully guaranteed. The transferability of a setup from its calibration case to other cases, where experimental data are not available, is not always reliable, and result-oriented tuning is often necessary. The deficiency is believed to be caused majorly by the imperfectness in the closure models that are required to reconstruct the processes occuring at the interface between phases. The other is that the state of the art multi-fluid model is usually limited to certain flow regimes. It fails to capture the transition between different flow regimes, e.g. bubbly flow to churn-turbulent flow, which are frequently encountered in the practice. This work aims to present a framework for generalized modelling of multiphase flow and the efforts made in the CFD department at HZDR towards closure model development. A new solver for the realization and validation of the framework is developed on the basis of the open source CFD code OpenFOAM. It is capable of capturing both dispersed and resolved gaseous structures in the liquid as well as the transfer between them.