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3 Publications

Modeling free surface flows relevant to a PTS scenario: comparison between experimental data and three RANS based CFD-codes - Comments on the CFD-experiment integration and best practice guideline

Bartosiewicz, Y.; Seynhaeve, J.-M.; Vallee, C.; Höhne, T.; Laviéville, J.

This paper presents some results concerning a benchmark for stratified two-phase flows conducted in the frame of the European Platform for NUclear REactor SIMulations (NURESIM). This benchmark relies on the FZD slug flow experiment performed in the Horizontal Air/Water Channel (HAWAC). For this test bench, special experimental arrangements have been taken in order to be able to properly model the boundary and initial conditions with CFD. A picture sequence recorded with a high-speed camera was used as reference for comparison with the simulations. For this benchmark, three different codes have been tried out. CFX was used with a turbulent two-fluid model in which a special turbulence damping function was implemented in the specific dissipation rate of the turbulent kinetic energy. This allowed a good qualitative representation of the slug dynamics, even though quantitative comparison were less relevant because of difficulties in modelling the inlet instabilities. The VOF approach in its laminar and turbulent form was also tried out trough the FLUENT code and was found to be inappropriate for those conditions due to the high velocity slip between phases. Moreover, NEPTUNE_CFD was tested with a new implemented model allowing free surface location and the computation of momentum transfer across this interface. This Large Interface Model (LIM) enables to detect "stratified cells" from the other and hence to apply local closure law. With this model, the results agreed well with experimental data qualitatively and quantitatively. This benchmark experience also allowed to draw basis concerning a best practice guideline in numerical simulation related to those flows in nuclear thermal hydraulics.

Keywords: stratified two-phase flow; free surface flow; slug flow; CFD; benchmark

  • Contribution to proceedings
    XCFD4NRS - Experiments and CFD Code Applications to Nuclear Reactor Safety, 10.-12.09.2008, Grenoble, France
    Paper HOR-01
  • Lecture (Conference)
    XCFD4NRS - Experiments and CFD Code Applications to Nuclear Reactor Safety, 10.-12.09.2008, Grenoble, France
  • Nuclear Engineering and Design 240(2010), 2375-2381
    DOI: doi:10.1016/j.nucengdes.2010.04.032

Permalink: https://www.hzdr.de/publications/Publ-11031
Publ.-Id: 11031