Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Comparative Analysis of k-ω SST Model and Porous Approach for HTGR Core Section Calculation

12/10/2025 2025 - #04 Modelling processes at nuclear facilities

Chubarov M.A. Zakharov M.Y. Tikhomirov G.V.

DOI: https://doi.org/10.26583/npe.2025.4.13

UDC: 621.039.52.034.3; 532.546.2

This study presents a comparative analysis of two geometric representations of the flow domain within RANS modeling for a segment of the high-temperature gas-cooled reactor (HTGR) core: a realistic representation with explicit modeling of fuel spheres and a porous one based on averaging the medium’s properties. The simulations were carried out using the LOGOS software package with the k-ω SST turbulence model. The realistic representation captures local flow and heat-transfer effects, including recirculation zones, accelerations within inter-particle gaps, and temperature peaks reaching up to 1310 K. In contrast, the porous approximation provides a smoothed, averaged picture with significantly lower values: the maximum velocity does not exceed 0.5 m/s, and the maximum temperature is 727 K. The average helium velocity in the pebble bed is 76.4% lower, and both the outlet temperature and the pressure drop differ by about 9%, accounting for the pre-computed linear resistance coefficients. The realistic approach is recommended for the analysis of local thermal-hydraulic characteristics, which are critical for transient and accident simulations, whereas the porous approximation, due to its computational efficiency, is suitable for preliminary studies and integral assessments, provided that the model is properly parameterized.

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CFD ЛОГОС HTGR ВТГР пористость TRISO

Link for citing the article: Chubarov M.A., Zakharov M.Y., Tikhomirov G.V. Comparative Analysis of k-ω SST Model and Porous Approach for HTGR Core Section Calculation. Izvestiya vuzov. Yadernaya Energetika. 2025, no. 4, pp. 175-189; DOI: https://doi.org/10.26583/npe.2025.4.13 (in Russian).

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