Semi-resolved function research on gas-solid two-phase coupling of high-temperature pebble beds

Zhao Peng; Wang Zhengyang; Wu hao; Niu Fenglei; Liu yang

doi:10.11884/HPLPB202638.250238

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Article Navigation > High Power Laser and Particle Beams > 2026 > Accepted Manuscript

Zhao Peng, Wang Zhengyang, Wu hao, et al. Semi-resolved function research on gas-solid two-phase coupling of high-temperature pebble beds[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250238

Citation:

Zhao Peng, Wang Zhengyang, Wu hao, et al. Semi-resolved function research on gas-solid two-phase coupling of high-temperature pebble beds[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250238

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Semi-resolved function research on gas-solid two-phase coupling of high-temperature pebble beds

doi: 10.11884/HPLPB202638.250238

School of Nuclear Science and Engineering, North China Electric Power University, Beijing 102206, China

Received Date: 2025-07-25
Accepted Date: 2025-10-28
Rev Recd Date: 2025-11-06

Available Online: 2025-11-15

Abstract

Abstract

Background
Accurately simulating the gas-solid coupled heat transfer in high-temperature pebble-bed reactors is challenging due to the complex configuration involving tens of thousands of fuel pebbles. Conventional unresolved CFD-DEM methods are limited in accuracy by their requirement for coarse fluid grids, whereas fully resolved simulations are often prohibitively expensive.
Purpose
This study aims to develop a semi-resolved function model suitable for fine fluid grids to enable accurate and efficient coupled thermal-fluid simulation in pebble beds.
Method
A Gaussian kernel-based semi-resolved function was introduced to smooth physical properties around particles and compute interphase forces via weighted averaging. The key parameter, the dimensionless diffusion time, was optimized through comparison with Voronoi cell analysis. The model was implemented in an open-source CFD-DEM framework and validated against both a single-particle settling case and a fluidized bed experiment.
Results
Voronoi cell analysis determined the optimal diffusion time to be 0.6. Exceeding this value over-smoothens the spatial distribution and obscures local bed features. The single particle settling case demonstrated excellent agreement with experimental terminal velocities under various viscosities. The fluidized bed simulation successfully captured porosity distribution and the relationship between fluid velocity and particle density, consistent with experimental data. Application to HTR-10 pebble bed thermal-hydraulics showed temperature distributions aligning well with the SA-VSOP benchmark.
Conclusions
The proposed semi-resolved function model effectively overcomes the grid size limitation of traditional CFD-DEM, accurately capturing interphase forces in sub-particle-scale grids. It provides a high-precision and computationally viable scheme for detailed thermal-fluid analysis in advanced pebble-bed reactors.
- high-temperature pebble beds,
- semi-resolved function,
- CFD-DEM,
- particle,
- Gaussian kernel function.

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References(22)

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