DEM-CFD simulation of helium flow characteristics in randomly packed bed for fusion reactors

Wu, Zhenxing; Wu, Yingwei; Tang, Simiao; Liu, Di; Qiu, Suizheng; Su, G.H.; Tian, Wenxi

doi:10.1016/j.pnucene.2018.07.010

Cited by 28 publications

(10 citation statements)

References 11 publications

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“…The coolant flow characteristics can be studied by computational fluid dynamical (CFD) simulation (e.g., k ε model in ANSYS fluent (Li et al, 2012;Wu et al, 2018d), CFD-DEM coupled method (Li and Ji, 2013;Chen et al, 2016Chen et al, , 2017a, direct numerical simulation (DNS) (Shams et al, 2013b) or large eddy simulation (LES) (Ebara et al, 2010)) to study the interstitial flow between pebbles, or by thermalfluid network analysis code (e.g., Flownex (Venter and Lamprecht, 2012). In general, ANSYS fluent or most CFD codes, in combination with suitable RANS (Reynolds Averaged Navier-Stokes) and LES models, are suitable to simulate the local details of flow, turbulence and heat transfer, and limited scales whole thermal-hydraulic system, supposing the huge numbers of grids are allowed by computer-clusters or super-computers.…”

Section: Coolant Materials and Flowmentioning

confidence: 99%

A review of pebble flow study for pebble bed high temperature gas-cooled reactor

Jiang

Yang

et al. 2019

Exp. Comput. Multiph. Flow

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The pebble bed high temperature gas-cooled reactor is a promising generation-IV reactor, which uses large fuel pebbles and helium gas as coolant. The pebble bed flow is a fundamental issue for both academic investigation and engineering application, e.g., reactor core design and safety analysis. This work performed a review of recent progress on pebble flow study, focusing on the important issues like pebble flow, gas phase hydrodynamics, and inter-phase heat transfer (thermal hydraulics). Our group's researches on pebble flow have also been reviewed through the aspects of phenomenological observation and measurement, voidage distribution, geometric and parameter optimization, pebble flow mechanisms, flow regime categorization, and fundamentals of modelings of pebble flow and radiation. Finally, the major problems or possible directions of research are concluded which would be some of our focuses on the pebble bed flow study.

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Section: Coolant Materials and Flowmentioning

confidence: 99%

A review of pebble flow study for pebble bed high temperature gas-cooled reactor

Jiang

Yang

et al. 2019

Exp. Comput. Multiph. Flow

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“…The discrete element method (DEM), proposed by Cundall and Strack [55], is currently widely used. For example, DEM models were adopted in the debris bed formation simulations of the pressurized water reactor [56,57], the fluid-structure coupling behavior of multiphase flow in accelerator-driven system [58,59], and the helium flow behavior in the spherical bed of a fusion reactor [60]. Thus, the DEM model was employed in this work to simulate the pebble-packing process.…”

Section: Simulation Methods and Parametersmentioning

confidence: 99%

Effects of the Aspect Ratio and Cross-Sectional Area of Rectangular Tubes on Packing Characteristics of Mono-Sized Pebble Beds

et al. 2023

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The packing characteristics of a pebble bed are essential to understand the heat- and mass-transfer processes occurring within a granular system. Therefore, the packing characteristics of rectangular prismatic pebble beds randomly packed with mono-sized pebbles are analyzed. In terms of the average and local packing fraction distribution, coordination number, and radial distribution function, the effects of the rectangular tube aspect ratio and cross-sectional area on the packing properties of pebble beds are explored in depth. The findings indicate that the packing structures of the rectangular pebble bed exhibit noticeable fixed-wall effects. The average packing fraction and coordination number gradually decline as the rectangular tube aspect ratio rises. Close to the fixed wall, a noticeable wall effect can be seen in the distribution of axial and local packing fractions and the pebble center distribution. The wall effect has an increasing effect on the axial and local packing fraction distributions in rectangular tubes with increasing aspect ratios. Additionally, the average packing fraction and the average coordination number also increase as the cross-sectional area increases, indicating a gradual weakening of the wall effect as the cross-sectional area increases. Furthermore, the cross-sectional area and aspect ratio of the rectangular tubes affect the RDF values of the rectangular pebble beds but have no impact on the RDF features. The findings reported in this paper will be helpful for designing and optimizing pebble beds in the breeding blanket of fusion reactors.

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“…In the packed bed, the gas flows non-uniformly. Several gas flow simulations in packed beds 23,24,27,29,30) showed that the gas flow concentrated to fairly thicker flow channels rather than passing through thinner void space. Therefore, it is important to extract the flow channel structure formed in the packed bed.…”

Section: Flow Paths In Packed Bedmentioning

confidence: 99%

“…In recent year, several analyses of the fluid flow in the void space in the packed bed have been performed. [22][23][24][25][26][27][28][29][30] The shape of the void space is reflected to the computational grids. Therefore, the effects of the shape and the connection of the void space are automatically reflected to the flow behavior and the pressure drop.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Void Structure in Deforming Packed Bed of Mono-dispersed Spherical Particles

Nogami

Yamawaki

2020

ISIJ Int.

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The void structure in the deforming packed bed like cohesive zone of blast furnace was discussed. The examined packed bed consisted of mono-dispersed spherical particles and was numerically prepared by using the discrete element method. From the obtained packing particle structure, the characteristics of the void space, namely voidage, surface area, hydraulic radius, flow path network structure, width and length of the flow path, were extracted. The actual hydraulic radius deviated from the one calculated from the bed shrinkage with the bed deformation, and this deviation resulted the large difference in the pressure drop in the packed bed. The flow path (void) network was successfully extracted from the particle packing structure. Additionally, distributions of the path width and length were obtained. The choking of flow path with bed shrinkage can be quantitatively visualized. In the softening ore particle bed with nut coke mixing, the flow path structures around ore and nut coke particles showed different behavior. With the obtained characteristics of the void structure, the variations of the pressure drops in the reduction test under loading and in the softening ore layer with coke mixing can be explained.

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DEM-CFD simulation of helium flow characteristics in randomly packed bed for fusion reactors

Cited by 28 publications

References 11 publications

A review of pebble flow study for pebble bed high temperature gas-cooled reactor

A review of pebble flow study for pebble bed high temperature gas-cooled reactor

Effects of the Aspect Ratio and Cross-Sectional Area of Rectangular Tubes on Packing Characteristics of Mono-Sized Pebble Beds

Analysis of Void Structure in Deforming Packed Bed of Mono-dispersed Spherical Particles

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