Comparison of pebble bed velocity profiles between high-fidelity and intermediate-fidelity codes

David Reger, Elia Merzari, Paolo Balestra, Sebastian Schunert, Yassin A. Hassan

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

1 Scopus citations


Recent interest for the development of high-temperature gas reactors has increased the need for more advanced understanding of flow characteristics in randomly packed pebble beds. A proper understanding of these flow characteristics can provide a better idea of the cooling capabilities of the system in both normal operation and accident scenarios. In order to enhance the accuracy of computationally efficient, intermediate fidelity modeling, high-fidelity simulation may be used to generate correlative data. For this research, NekRS, a GPU-enabled spectralelement computational fluid dynamics code, was used in order to produce the high-fidelity flow data for beds of 1,568 and 45,000 pebbles. Idaho National Lab's Pronghorn porous media code was used as the intermediate fidelity code. The results of the high-fidelity model were separated into multiple concentric regions in order to extract porosity and velocity averages in each region. The porosity values were input into the Pronghorn model and the resulting velocity profile was compared with that from NekRS. Both cases were run with a Reynolds number of 20,000 based on pebble diameter. The Pronghorn results were found to significantly overestimate the velocity in the outermost region indicating that changes in the porosity alone do not cause the difference in fluid velocity. We conclude that further work is necessary to develop a more effective drag coefficient correlation for the near-wall region and improve predictive capabilities of intermediate fidelity models.

Original languageEnglish (US)
Title of host publicationStudent Paper Competition
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Print)9784888982566
StatePublished - 2021
Event2021 28th International Conference on Nuclear Engineering, ICONE 2021 - Virtual, Online
Duration: Aug 4 2021Aug 6 2021

Publication series

NameInternational Conference on Nuclear Engineering, Proceedings, ICONE


Conference2021 28th International Conference on Nuclear Engineering, ICONE 2021
CityVirtual, Online

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering


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