NuFOAM: OpenFOAM in

nuclear safety applications Juho Peltola1 • Juhaveikko Ala-Juusela2 • Tomas Brockmann2 • Karoliina Ekström3 • Jarto Niemi1 • Giteshkumar

Patel4 • Timo Pättikangas1 • Timo Siikonen2 • Vesa Tanskanen4 • Timo Toppila3

1VTT Technical Research Centre of Finland • 2Aalto University • 3Fortum Power and Heat Oy • 4Lappeenranta

University of Technology

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sähköpostiosoitteella: vtt.visualistit@vtt.fi.

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ajoissa ennen seminaaria (miel. 5 päivää

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posteri tulostettavaksi os.

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Voit tarvittaessa noutaa itse tulostetun

posterin VTT:n värikopioinnista:

VM5, 1. kerros, Esa Tanskanen

VTT TECHNICAL RESEARCH CENTRE OF FINLAND

www.vtt.fi

CEA DEBORA5 Experiment R-12 boiling in a vertical pipe

Two-phase solver development The OpenFOAM® based two-fluid CFD solver has been

capabilities have been extended to modeling of subcooled

nucleate boiling, along with several other enhancements. The

results have been benchmarked against experimental and

numerical results. Direct contact condensation (DCC) models

have been implemented and first test simulations of steam

condensation in a water pool have been carried out.

A C E

Frank et al. (2011)

OECD/NEA PSBT 1.2211 Benchmark case A steady-state PWR subchannel experiment

OpenFOAM® and OpenCFD® are registered trademarks of OpenCFD Ltd. (ESI Group)

and this project has not been endorsed or approved by OpenCFD Ltd.

Introduction Compared to commercial solvers, the benefits of an open source

CFD code are transparency, infinite customizability and lack of

licensing fees, which brings the cost structure of massively

parallel computation down to a feasible level. Compared to other

open source CFD codes, the benefits of OpenFOAM® are a large,

active and growing user base, modern approach to mesh handling

with unstructured and polyhedral meshes, parallelization and an

object oriented code structure that makes it fast and easy to

implement new models and solvers in the top level code.

Single-phase flow simulations Fortum took part in the MATIS-H benchmark, simulating a

horizontal fuel rod bundle with a spacer grid utilizing RANS

turbulence modeling. The main emphasis of Aalto University has

been on the VVER-440 fuel rod bundle with different turbulence

modeling approaches, including Large-Eddy Simulation (LES) and

Detached-Eddy Simulation (DES).

OECD/NRC MATIS-H Benchmark Single-phase horizontal fuel rod bundle with a spacer grid. The

Fortum submission was selected as the best k-ε approximation of

the experiment.

VVER-440 fuel rod bundle simulations

1 cm above the spacer grid

k-ε k-ω SST RSTM

a) c)

b) d)

a) 1 cm

b) 2 cm

c) 5 cm

d) 20 cm

above the

spacer grid