1. NAME AND TITLE
A Lagrangian-based computational fluid dynamics code for nuclear thermal hydraulics
and safety applications.
The SOPHIA code is mainly a
solver program. Therefore, it requires a preprocessor for input
generation and a
postprocessor for data analysis.
A MATLAB script can be used for
input generation. For postprocessing, the results can be
processed using ParaView
since they are formatted in *.vtk.
Soo Kim (Professor of Seoul National University)
Young Beom Jo, So Hyun Park, Hae Yoon Choi, Tae Soo Choi, Su-San Park, Hee Sang
Yoo, Yelyn Ahn, Jin Hyun Kim, Tae Hoon Lee, Hoon Chae, Jin Woo Kim, Joo Ryong
Park, Do Hyun Kim
Department of Nuclear Engineering
National University, Gwanak-ro 1, Gwanak-gu
South Korea (08826)
Through the OECD Nuclear Energy
Agency Data Bank, Issy-Les Moulineaux, France.
3. CODING LANGUAGE AND COMPUTER
on a LINUX or UNIX Operating System
RSICC ID: C00857MNYCP00;
NEADB identifier is NEA-1911/01
4. NATURE OF PROBLEM SOLVED
methods used in nuclear safety analyses are generally mesh-based (or
grid-based), such as the finite difference method (FDM), finite element method
(FEM), and finite volume method (FVM). These mesh-based methods have a long
history and are thus very mature both mathematically and numerically. Based on
their robustness and efficiency, they dominate the CFD field and have been used
in many applications, for which these methods produce very accurate results. Mesh-based
methods are generally good for confined computational domains and computation in
which the boundaries and interfaces do not move. However, they may not be the
most efficient for modeling highly nonlinear deformation or interface regions,
which are often involved in the severe accident and natural disasters related
to nuclear power plants. Because of this, a multiphysics smoothed-particle
hydrodynamics (SPH) code framework, SOPHIA, was recently developed at Seoul
National University (SNU) that focuses on key thermal hydraulics and safety-related
phenomena in nuclear reactor systems. SPH is one of the most well-known
Lagrangian methods; it can handle various types of physics extensively because
of its simplicity and ease of expressing and solving mathematical equations. SOPHIA
is written in C++ and is parallelized using graphics processing units. Like
other conventional CFD analysis codes, the applications of SOPHIA are mainly for
fundamental thermal hydraulics, multiphase flow, severe accidents, natural
disasters, and so on for various nuclear reactor types. Thus, the main physics
behind this code include (1) fluid flow, (2) heat transfer, (3) turbulence, (4)
melting/solidification, (5) multiphase, (6) natural convection, and (7)
diffusion. However, in principle, the SOPHIA code can be easily extended to and
is well suitable for other phenomena with some necessary modifications to the
equation of state (EOS) and the physical models.
5. METHOD OF SOLUTION
The SOPHIA code is
based on SPH, which is a meshless numerical method. It solves mass, momentum, and
energy conservations with the EOS and physical models in multidimensional space
and time (2D/3D). The basic mathematical equations are quite similar to conventional
CFDcode, except that the equations are solved in a Lagrangian framework.
6. RESTRICTIONS OR LIMITATIONS
There are no
limitations of the number of particles (the size of the problems) if sufficient
GPU memory is available. For a single GPU, the maximum number of particles is 10
to 15 million.
7. TYPICAL RUNNING TIME
The typical run
time highly depends on the sizes and types of problems being solved. Lagrangian‑based
numerical methods generally require a large amount of computational time. It
may take a couple of minutes to a couple of weeks.
8. COMPUTER HARDWARE REQUIREMENTS
parallelized using GPUs. Therefore, to run this code, a GPU card should be
installed with the CUDA library.
9. COMPUTER SOFTWARE REQUIREMENTS
The current SOPHIA
code runs in a Linux (Ubuntu) environment. However, a Windows version can be
generated with some modifications, if required.
S.H., Jo, Y.B., Kim, E.S., “Development of Multi-GPU-Based Smoothed Particle
Hydrodynamics Code for Nuclear Thermal-hydraulics and Safety: Potential and
Challenges,” Frontiers in Energy Research, Vol. 8, 2020.
Y.B., Park, S.H., Choi, H.Y., Jung, H.W., Kim, Y.J., Kim, E.S., “SOPHIA:
Development of Lagrangian-based CFD Code for Nuclear Thermal-Hydraulics and
Safety Applications,” Annals of Nuclear Energy, Vol. 124, pp. 132–149,
S.H., Choi, T.S., Choi, H.Y., Jo, Y.B., Kim, E.S., “Simulation of a
Laboratory-scale Experiment for Wave Propagation and Interaction with a
Structure of Undersea Topography Near a Nuclear Power Plant using a
Divergence-Free SPH,” Annals of Nuclear Energy, Vol. 122, pp. 340–351,
S.H., Jo, Y.B., and Kim, E.S., “High Resolution 3-D Simulation of Melt Jet
Break-up Phenomenon using Multi-GPU-based Smoothed Particle Hydrodynamics Code
and Comparison with Experimental Result,” ICONE-28, August 2–6, Anaheim, USA,
Y.B., and Kim, E.S., “Numerical Simulation on LMR Molten-Core Centralized
Sloshing Behaviors with Single/Multi-Phase Smoothed Particle Hydrodynamics
Based on Novel Density Formulation,” NURETH-18, August 18–23, 2019 Portland,
Oregon, USA, 2019.
Y., Jo, Y.B., Park, S.H., Kim, J.W., and Kim, E.S., “SPH Simulation on Single
Bubble Behavior in Linear Shear Flow,” NURETH-18, August 18–23, 2019 Portland,
Oregon, USA, 2019.
et al., “Development of SOPHIA-MARS Integrated Code Based on Smoothed Particle
Hydrodynamics Method and Preliminary Simulation on In-Vessel Retention and
External Reactor Vessel Cooling,” Transactions of the Korean Nuclear Society
Spring Meeting Jeju, Korea, May 21–22, 2020.
et al., “Simulation of Jet Break-up in Complicated Structure in BWR Lower
Plenum using Smoothed Particle Hydrodynamics,” Transactions of the Korean
Nuclear Society Spring Meeting Jeju, Korea, May 21–22, 2020.
11. CONTENTS OF CODE PACKAGE
The package is transmitted digitally
as a download link in .zip format. It includes reference material,
documentation, source files, and sample problems. Application executables are
included with the package.
12. DATE OF ABSTRACT
KEYWORDS: Lagrange equations, accident analysis,
hydrodynamics, multiphase flow, safety analysis, severe accident, thermal