MULTISCALE ANALYSES OF FLOW IN A 5X5 ROD BUNDLE: FROM DNS AND SUBCHANNEL TO COARSE-MESH CFD

Adam R. Kraus, Elia Merzari

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

The fast and accurate evaluation of flow and heat transfer phenomena in rod bundles has been of longstanding interest in nuclear engineering. Computational Fluid Dynamics (CFD) can provide accurate but relatively expensive estimates, such that simulations of very long transients and high spatial detail are precluded. On the other hand, subchannel codes are relatively fast and can provide pin-level estimates, but have substantial empiricism in evaluating aspects such as crossflows and turbulent mixing coefficients. A multiscale method for bridging this knowledge/speed gap, based on the Subchannel CFD (”SubChCFD”) method of Liu et al. [1], is demonstrated here for a 5x5 square rod bundle geometry. The method is implemented in the commercial code Star-CCM+, and benchmarked against Liu's data. The geometry was chosen in part due to the availability of DNS data at relevant Reynolds number of a similar configuration for comparison. The SubChCFD results are variously compared against results from DNS, LES, wall-resolved RANS, coarse CFD, and subchannel methods. As an example of the flexibility of the SubChCFD approach, the”Hi2Lo” approach is demonstrated by using the DNS data as a correction to the original friction factor correlations in the SubChCFD. These are verified to improve the predictions. The potential of SubChCFD for modeling the narrow gap instability is also assessed. Extensions of the method, including for wire-wrapped rod bundle geometries, are discussed. Future work will implement the method into Pronghorn, with a unified pipeline via the Cardinal wrapper between the codes NekRS, Pronghorn, and BISON, to solve fuel performance problems.

Original languageEnglish (US)
Title of host publicationProceedings of Advances in Thermal Hydraulics, ATH 2022 - Embedded with the 2022 ANS Annual Meeting
PublisherAmerican Nuclear Society
Pages430-444
Number of pages15
ISBN (Electronic)9780894487811
DOIs
StatePublished - 2022
Event5th International Topical Meeting on Advances in Thermal Hydraulics 2022, ATH 2022, held in conjunction with the 2022 American Nuclear Society ,ANS Annual Meeting - Anaheim, United States
Duration: Jun 12 2022Jun 16 2022

Publication series

NameProceedings of Advances in Thermal Hydraulics, ATH 2022 - Embedded with the 2022 ANS Annual Meeting

Conference

Conference5th International Topical Meeting on Advances in Thermal Hydraulics 2022, ATH 2022, held in conjunction with the 2022 American Nuclear Society ,ANS Annual Meeting
Country/TerritoryUnited States
CityAnaheim
Period6/12/226/16/22

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Nuclear Energy and Engineering
  • Nuclear and High Energy Physics

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