LES analysis of the flow in a simplified PWR assembly with mixing grid

Bieder, Ulrich; Falk, François; Fauchet, Gauthier

doi:10.1016/j.pnucene.2014.03.014

Cited by 48 publications

(20 citation statements)

References 13 publications

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“…Under static state, due to the symmetrical geometry of the subchannel, the transverse velocity fields at the cross-sections are axially symmetrical with two vortices rotating reversely in the rod gaps (Figure 5a), with a sketch of the subchannel in the lower left corner). A similar transverse flow field is also obtained in Bieder et al's study [34]. Further downstream, the nucleate boiling intensifies, and the transverse velocity increases.…”

Section: Transverse Flowsupporting

confidence: 84%

Numerical Study of the Effect of the Rolling Motion on the Subcooled Flow Boiling in the Subchannel

et al. 2022

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The marine environment may change the force on the fluid and inevitably influence bubble behavior and the two-phase flow in the reactor core, which are vital to the safety margin of a nuclear reactor. To explore the effect of the marine motion on the flow and heat transfer features of subcooled flow boiling in the reactor core, the volume of fluid (VOF) method is employed to reveal the interaction between the interface structure and two-phase flow in the subchannel under rolling motion. The variations of several physical parameters are obtained, including the transverse flow, the vapor volume fraction, the vapor adhesion ratio, and the phase distribution of boiling two-phase flow with time. Sensitivity analyses of the amplitude and the period of the rolling motion were performed to demonstrate the mechanisms of the influence of the rolling motion. We found that the transverse flow in the subchannel was mainly affected by the Euler force under the rolling motion. In contrast to the two-phase flow in the static state, the vapor volume fraction and vapor adhesion ratio show different characteristics under rolling motion. Additionally, the onset of significant void (OSV) point changes periodically under rolling motion.

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Section: Transverse Flowsupporting

confidence: 84%

Numerical Study of the Effect of the Rolling Motion on the Subcooled Flow Boiling in the Subchannel

et al. 2022

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“…Many recent attempts to simulate the fluid flow in a fuel assembly can be found in the literature. Bieder et al [16] showed that, downstream close to the mixing vane the turbulence is isotropic and anisotropic further downstream. Chen et al in [17] showed that simulation should count at least a 4 by 4 rod bundle to represent a full bundle.…”

Section: Introduction: Industrial Challenge and Purpose Of The Papermentioning

confidence: 99%

Advanced benchmark of the flow through a mixing vane grid – Large eddy simulation validation

Farges¹,

Gauffre

Benhamadouche³

et al. 2021

Nuclear Engineering and Design

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“…Numerous experimental or numerical studies have shown the existence of reorganisation phenomena in the transverse flow large-scale structures (see the review in appendix A from Kang and Hassan [1]). In particular, the AGATE experimental results [2] featured a global 90°rotation of the cross-flow pattern between the near and the far wake of a mixing grid. This reorganisation is shown in Figure 1: a sketch of a 5 Â 5 rod bundle fitted with a mixing grid, as well as colour plots of the transverse flow downstream a mixing grid are shown.…”

Section: Introductionmentioning

confidence: 99%

Hydraulic and statistical study of metastable phenomena in PWR rod bundles

Müller

2020

EPJ Nuclear Sci. Technol.

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The analysis of fuel rod bundle flows constitutes a key element of Pressurized-Water Reactors (PWR) safety studies. The present work aims at improving our understanding of nefarious reorganisation phenomena observed by numerous studies in the flow large-scale structures. 3D simulations allowed identifying two distinct reorganisations consisting in a sign change for either a transverse velocity in rod-to-rod gaps or for a subchannel vortex. A Taylor “frozen turbulence” hypothesis was adopted to model the evolution of large-scale 3D structures as transported-2D. A statistical method was applied to the 2D field to determine its thermodynamically stable states through an optimization problem. Similarities were obtained between the PWR coherent structures and the stable states in a simplified 2D geometry. Further, 2D simulations allowed identifying two possible flow bifurcations, each related to one of the reorganisations observed in 3D simulations, laying the foundations for a physical explanation of this phenomenon.

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LES analysis of the flow in a simplified PWR assembly with mixing grid

Cited by 48 publications

References 13 publications

Numerical Study of the Effect of the Rolling Motion on the Subcooled Flow Boiling in the Subchannel

Numerical Study of the Effect of the Rolling Motion on the Subcooled Flow Boiling in the Subchannel

Advanced benchmark of the flow through a mixing vane grid – Large eddy simulation validation

Hydraulic and statistical study of metastable phenomena in PWR rod bundles

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