Technische Universität Dresden
Two-phase CFD analyses in fuel assembly sub-channels of Pressurized Water Reactors under swirl conditions
Abstract
dc:description.abstractSingle-phase CFD calculations are already widely applied in nuclear industry for the thermal-hydraulic design optimization of fuel assemblies (FA). In contrast, two-phase CFD-applications are still in the state of development. The work presented in this thesis shows contributions towards the detailed two-phase modeling of boiling flows under swirl conditions in sub-channel geometries of pressurized water reactors (PWR) FAs, including a realistic description of the critical heat flux (CHF)-phenomena and identification of two-phase indicators characterizing CHF-phenomena. The numerical simulations were conducted with a 3-D CFD code (STAR CD) for various types of swirl generating components in FA. New insights regarding local void distribution in sub-channels under swirl conditions were obtained, which are relevant for CHF (“bubble pockets”). Furthermore, an enhanced wall partitioning model provides a more realistic description of the steep increase of the rod temperature due to CHF. Presented validation studies showed good agreement with the available experiments under PWR conditions for the radial void distributions at non-CHF conditions as well as for the CHF prediction. The results performed in this thesis show the incentives and chances of two-phase CFD applications for the development of thermal-hydraulically optimized PWR spacer grids with regard to heat transfer and improvement to the CHF behaviour.
Degree
thesis:*- Level thesis:degree_level
- thesis.doctoral
- Grantor dc:publisher
- Technische Universität Dresden
- Year
- 2008
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Salnikova, Tatiana
- Contributors dc:contributor
-
- Huhn, Jörg
- Reinders, Rudi
- Lischke, Wolfgang
- Lo, Simon
- Wehle, Franz