HZDR baseline model strategy
Quite different closure models are found in literature for one phenomenon. The selection of closures and related parameters usually aims on good agreement with experimental data for single or few experiments. However, the local hydrodynamic phenomena which have to be reflected by the closures are often very similar. For this reason the closures for certain flow patterns as bubbly flows or separated flows should not be limited on special applications or apparatuses.
At the HZDR baseline models for poly-dispersed bubble flows and for separated flows all closure models including all parameters are well defined. The section was done basing on physical considerations and own experiences. The baseline models are applied to different applications (e.g. for bubbly flows in pipes, bubble columns of different geometry and size, bubble plumes, air-lift reactors and others). For most of the cases good agreement with experimental data is observed. For cases that show deviations the reasons for have to be identified and better models have to be figured out. The new model should show an overall improvement. By this procedure the validity of the baseline model will be improved successively and the predictive capabilities increase.
- Lucas, D.; Rzehak, R.; Krepper, E.; Ziegenhein, Th.; Liao, Y.; Kriebitzsch, S.; Apanasevich, P.
A strategy for the qualification of multi-fluid approaches for nuclear reactor safety.
Nuclear Engineering and Design 299(2016), 2-11