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Title: Toward Exascale: Overview of Large Eddy Simulations and Direct Numerical Simulations of Nuclear Reactor Flows with the Spectral Element Method in Nek5000

Journal Article · · Nuclear Technology

At the beginning of the last decade, Petascale supercomputers (i.e., computers capable of more than 1 petaFLOP) emerged. Now, at the dawn of exascale supercomputing, we provide a review of recent landmark simulations of portions of reactor components with turbulence-resolving techniques that this computational power has made possible. In fact, these simulations have provided invaluable insight into flow dynamics, which is difficult or often impossible to obtain with experiments alone. We focus on simulations performed with the spectral element method, as this method has emerged as a powerful tool to deliver massively parallel calculations at high fidelity by using large eddy simulation or direct numerical simulation. We also limit this paper to constant-property incompressible flow of a Newtonian fluid in the absence of other body or external forces, although the method is by no means limited to this class of flows. We briefly review the fundamentals of the method and the reasons it is compelling for the simulation of nuclear engineering flows. We review in detail a series of Petascale simulations, including the simulations of helical coil steam generators, fuel assemblies, and pebble beds. Even with Petascale computing, however, limitations for nuclear modeling and simulation tools remain. In particular, the size and scope of turbulence-resolving simulations are still limited by computing power and resolution requirements, which scale with the Reynolds number. In the final part of this paper, we discuss the future of the field, including recent advancements in emerging architectures such as GPUbased supercomputers, which are expected to power the next generation of high-performance computers.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
DOE Contract Number:
AC02-06CH11357
OSTI ID:
1840530
Journal Information:
Nuclear Technology, Vol. 206, Issue 9
Country of Publication:
United States
Language:
English

References (34)

CFD methodology and validation for single-phase flow in PWR fuel assemblies journal September 2010
Flow-induced vibration analysis of a helical coil steam generator experiment using large eddy simulation journal October 2017
Recent progress in the development of the Elliptic Blending Reynolds-stress model journal February 2015
Direct numerical and large eddy simulations in nuclear applications journal June 1999
Large-scale large eddy simulation of nuclear reactor flows: Issues and perspectives journal February 2017
On the use of (U)RANS and LES approaches for turbulent incompressible single phase flows in nuclear engineering applications journal February 2017
Interface Tracking Investigation of Geometric Effects on the Bubbly Flow in PWR Subchannels journal August 2018
Direct Numerical Simulation and Wall-Resolved Large Eddy Simulation in Nuclear Thermal Hydraulics journal June 2019
Spectral and modal analysis of the flow in a helical coil steam generator experiment with large eddy simulation journal December 2019
Comparison of experimental and simulation results on interior subchannels of a 61-pin wire-wrapped hexagonal fuel bundle journal November 2018
Invariant analysis of the Reynolds stress tensor for a nuclear fuel assembly with spacer grid and split type vanes journal June 2019
A spectral element method for fluid dynamics: Laminar flow in a channel expansion journal June 1984
Petascale algorithms for reactor hydrodynamics journal July 2008
Direct Numerical Simulation of the Flow Through a Randomly Packed Pebble Bed journal January 2020
High-Order Methods for Incompressible Fluid Flow book January 2009
Spectral Methods: Evolution to Complex Geometrics and Applications to Fluid Dynamics book January 2007
An Overlapping Schwarz Method for Spectral Element Solution of the Incompressible Navier–Stokes Equations journal May 1997
High-pass filtered eddy-viscosity models for large-eddy simulations of transitional and turbulent flow journal June 2005
The filtering analog of the variational multiscale method in large-eddy simulation journal August 2003
A novel numerical treatment of the near-wall regions in the k ω class of RANS models journal August 2018
On the Strong Scaling of the Spectral Element Solver Nek5000 on Petascale Systems conference January 2016
Comparative study of spectral-element and finite-volume solvers for direct numerical simulation of synthetic jets journal January 2019
Large Eddy Simulation of the Flow Behavior in a Simplified Helical Coil Steam Generator journal June 2018
High-Fidelity Simulation of Flow-Induced Vibrations in Helical Steam Generators for Small Modular Reactors journal July 2018
Accurate prediction of the wall shear stress in rod bundles with the spectral element method at high Reynolds numbers journal December 2014
Numerical Simulation and Proper Orthogonal Decomposition of the Flow in a Counter-Flow T-Junction journal July 2013
Jet stability and wall impingement flow field in a thermal striping experiment journal December 2017
Spectral element applications in complex nuclear reactor geometries: Tet-to-hex meshing journal February 2020
Stereoscopic particle image velocimetry measurements of flow in a rod bundle with a spacer grid and mixing vanes at a low Reynolds number journal October 2017
On the discontinuity of the dissipation rate associated with the temperature variance at the fluid-solid interface for cases with conjugate heat transfer journal August 2017
Benchmark exercise for fluid flow simulations in a liquid metal fast reactor fuel assembly journal March 2016
Numerical simulation of turbulent flow in a 37-rod bundle journal March 2007
An MPI/OpenACC implementation of a high-order electromagnetics solver with GPUDirect communication journal July 2016
Scaling Limits for PDE-Based Simulation (Invited) conference June 2015