Post Test Calculation with CFX-4 of the OECD/CSNI International Standard Problem Nr. 43

The need of the experimental support for validation of the computational tools to be applied to analyze the mixing of diluted slugs has been recognized in various countries. The test series for the International Standard Problem ISP-43 provides a platform for experiences to be applied to the simulation of a well-defined test series. Test A of the UM2x4 loop test facility was calculated with the CFD Code CFX-4.3. The results show qualitatively good agreement with the experimental data. The structure of the flow field and the form of the propagating temperature perturbation front are well modeled by the CFD code. However, deviations occur at local positions. Comparative calculations with and without taking into account buoyancy have shown, that buoyancy effects are noticeable, but the mixing is mainly momentum controlled.