Benchmark exercise for fluid flow simulations in a liquid metal fast reactor fuel assembly

Merzari, Elia; Fischer, Paul; Yuan, Hongyong; Tichelen, Katrien Van; Keijers, S.; Ridder, Jeroen de; Degroote, Joris; Vierendeels, Jan; Doolaard, H.; Gopala, Vinay R.; Roelofs, F.

doi:10.1016/j.nucengdes.2015.11.002

Cited by 71 publications

(23 citation statements)

References 9 publications

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“…This effort is described in Pacio et al (2017). There, it is shown that the wall resolved RANS model consisting of about 200 million cells can predict the pressure drop at similar accuracy as described earlier for Merzari et al (2016), Doolaard et al (2015), and Kennedy et al (2015). The main focus for validation was on temperatures and heat transport.…”

Section: Numerical Programmentioning

confidence: 74%

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Towards validated prediction with RANS CFD of flow and heat transport in a wire-wrap fuel assembly

Roelofs

Uitslag-Doolaard

Dovizio

et al. 2019

Nuclear Engineering and Design

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Liquid metal fast reactors (LMFRs) are foreseen to play an important role in the future of nuclear energy, thanks to their increased fuel utilization and safety features profiting from the optimal heat transfer performance of the metallic coolants. Accurate thermal-hydraulic analysis of their fuel assemblies, typically employed with wire-wraps as spacers, is recognized as a crucial scientific and engineering contribution to support the deployment of such technology. This challenges the modeling and simulation community. To this aspect, various reference databases (both experimental and numerical) for different wire-wrapped fuel assembly configurations have been created recently and are being used for validation of engineering simulation approaches based on Reynolds Averaged Navier Stokes (RANS) modelling. These databases include: • 7-pin rod bundle: A detailed experiment with Particle Image Velocimetry (PIV) is performed. In order to allow accurate measurements of the flow topology, a matched-index-of-refraction technique was used employing water as working fluid. • 19-pin bundle: A series of experiments is performed covering a wide range of Reynolds and Peclet numbers as well as thermal powers. The experiments use liquid lead-bismuth eutectic as working fluid. The measurements include pressure drop and local temperatures. • 61-pin rod bundle: This large eddy simulation including conjugate heat transfer from the pin cladding to the coolant allows to bridge the gap from small bundles (less than 37 pins) to large bundles (more than 37 pins). In literature, a fundamental different behavior has been observed for small bundles compared to large bundles. • 127-pin bundle: Isothermal experiments using lead-bismuth eutectic characterizing pressure drop are performed on a full scale fuel assembly representative for the MYRRHA reactor. • Infinite pin bundle: This reference quasi-direct numerical simulation profits from periodicity in all directions. It provides a detailed view into the flow field and in addition reveals details of the heat transfer from the rod bundle into the flow. Reference databases aim to serve the nuclear scientific community to validate engineering simulation approaches. The paper will introduce these reference databases, and how they have been used to validate RANS based turbulence modelling approaches within a mainly European context.

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Section: Numerical Programmentioning

confidence: 74%

“…The numerical benchmark reported by Merzari et al (2016), comprised 2 isotropic (realizable k-ε and SST k-ω) and 1 anisotropic (cubic k-ε) wall resolved RANS models. Mean velocities were predicted within 10% and in many cases within 5% with all applied turbulence models and a wall resolved mesh.…”

Section: Numerical Programmentioning

confidence: 99%

Towards validated prediction with RANS CFD of flow and heat transport in a wire-wrap fuel assembly

Roelofs

Uitslag-Doolaard

Dovizio

et al. 2019

Nuclear Engineering and Design

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“…For some special applications, experimental data are utilized for a specific geometry and used to validate the numerical results [17,18]. For systems with lacking the experimental results, direct numerical simulations are used for generating test cases to verify the accuracy of a numerical implementation [19,20].…”

Section: Introductionmentioning

confidence: 99%

Experimental validation of computational fluid dynamics for solving isothermal and incompressible viscous fluid flow

Abali

Savaş

2020

SN Appl. Sci.

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In order to validate a computational method for solving viscous fluid flows, experiments are carried out in an eccentric cylindrical cavity showing various flow formations over a range of Reynolds numbers. Especially, in numerical solution approaches for isothermal and incompressible flows, we search for simple experimental data for evaluating accuracy as well as performance of the computational method. Verification of different computational methods is arduous, and analytic solutions are only obtained for simple geometries like a channel flow. Clearly, a method is expected to predict different flow patterns within a cavity. Thus, we propose a configuration generating different flow formations depending on the Reynolds number and make the experimental results freely available in order to be used as an assessment criterion to demonstrate the reliability of a new computational approach.

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“…Recently, the university of Texas performed a number of experiments in a 61-rods test section for code validation, as reported in Goth et al (2018), and for studying vortical structures that may occur in the flow, as described in and in . Computational Fluid Dynamics (CFD) studies have focused on modelling the flow around a single wrapped-wire pin (Shams et al, 2018;Fischer et al, 2007), and on simulating the entire bundle for validation purposes (Pointer et al, 2008;Merzari et al, 2016;Obabko et al, 2016;Brockmeyer et al, 2017). Depending on the position of the wire, the flow is found, unexpectedly, to bend against the direction of the wire.…”

Section: Introductionmentioning

confidence: 99%

Understanding migratory flow caused by helicoid wire spacers in rod bundles: An experimental and theoretical study

Bertocchi

Rohde

Kloosterman

2019

International Journal of Heat and Fluid Flow

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The core of a Liquid Metal Fast Breeder Reactor (LMFBR) consists of cylindrical fuel rods that are wrapped by a helicoidally-wound wire spacer to enhance mixing and to prevent damage by fretting. It is known that the liquid metal close to the rod is forced to follow the wires, and that liquid metal further away from the rod crosses the wires (called: migratory flow). This work aims at gaining more insight into the physics behind migratory flow and to provide a model for its bending angle. To this purpose, the flow field in a 7-rods, wire-wrapped, hexagonal bundle with water is studied within the Reynolds number range of 4990-16330 by using Particle Image Velocimetry (PIV). Refraction of the light is minimized by using Fluorinated Ethylene Propylene (FEP), which is a refractive index-matching (RIM) material. These measurements confirm that liquid near the rod follows the helicoid path and bends crosswise with respect to the wire further away from the rod. A theoretical model for the bending angle of the flow is derived from the Euler equations and shows that the bending is primarily caused by the pressure gradient field induced by the wire. The model shows a very good correspondence with the experimentally obtained PIV data. These findings improve our understanding of the physics at play in rod bundle flows with wrapped wires and can be of assistance in developing practical correlations for frictional pressure losses and heat transfer in such bundles.

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Benchmark exercise for fluid flow simulations in a liquid metal fast reactor fuel assembly

Abstract: ABSTRACT

Cited by 71 publications

References 9 publications

Towards validated prediction with RANS CFD of flow and heat transport in a wire-wrap fuel assembly

Towards validated prediction with RANS CFD of flow and heat transport in a wire-wrap fuel assembly

Experimental validation of computational fluid dynamics for solving isothermal and incompressible viscous fluid flow

Understanding migratory flow caused by helicoid wire spacers in rod bundles: An experimental and theoretical study

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