Direct Numerical Simulation of the Flow through a Randomly Packed Pebble Bed

Yildiz, Mustafa; Botha, Gerrit; Yuan, Haomin; Merzari, Elia; Kurwitz, Richard; Hassan, Yassin

doi:10.1115/1.4045439

Direct Numerical Simulation of the Flow through a Randomly Packed Pebble Bed

Journal Article · Thu Oct 24 00:00:00 EDT 2019 · Journal of Fluids Engineering

DOI:https://doi.org/10.1115/1.4045439· OSTI ID:1571446

Yildiz, Mustafa ^[1]; Botha, Gerrit ^[2]; Yuan, Haomin ^[3]; Merzari, Elia ^[3]; Kurwitz, Richard ^[2]; Hassan, Yassin ^[2]

Texas A & M Univ., College Station, TX (United States). Dept. of Nuclear Engineering; Texas A&M University
Texas A & M Univ., College Station, TX (United States). Dept. of Nuclear Engineering
Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Science and Engineering Division

The proposition for molten salt and high-temperature gas-cooled reactors has increased the focus on the dynamics and physics in randomly packed pebble beds. Research is being conducted on the validity of these designs as a possible contestant for fourth-generation nuclear power systems. A detailed understanding of the coolant flow behavior is required in order to ensure proper cooling of the reactor core during normal and accident conditions. In order to increase the understanding of the flow through these complex geometries and enhance the accuracy of lower-fidelity modeling, high-fidelity approaches such as direct numerical simulation (DNS) can be utilized. Nek5000, a spectral-element computational fluid dynamics code, was used to develop DNS fluid flow data. The flow domain consisted of 147 pebbles enclosed by a bounding wall. In the work presented, the Reynolds numbers ranged from 430 to 1050 based on the pebble diameter and inlet velocity. Characteristics of the flow domain such as volume averaged porosity, axial porosity, and radial porosity were studied and compared with correlations available in the literature. Friction factors from the DNS results for all Reynolds numbers were compared with correlations in the literature. First- and second-order statistics show good agreement with available experimental data. Turbulence length scales were analyzed in the flow. Reynolds stress anisotropy was characterized by utilizing invariant analysis. Overall, the results of the analysis in the current study provide deeper understanding of the flow behavior and the effect of the wall in packed beds.

View Accepted Manuscript (DOE)

Research Organization:: Texas A&M Univ., College Station, TX (United States)

Sponsoring Organization:: USDOE Office of Nuclear Energy (NE)

Grant/Contract Number:: NE0008550

OSTI ID:: 1571446

Alternate ID(s):: OSTI ID: 1632276

Journal Information:: Journal of Fluids Engineering, Journal Name: Journal of Fluids Engineering Journal Issue: 4 Vol. 142; ISSN 0098-2202

Publisher:: ASMECopyright Statement

Country of Publication:: United States

Language:: English

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