Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Coupling of Serpent Neutron Transport Code toOpenFOAM

Ashkhen Nalbandyan

Center for Nuclear Technologies,Technnical University of Denmark,

Roskilde, Denmark

2018-11-29

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

1 Introduction

2 Theory

3 The buoyantBoussinesqPimpleFoam solver

4 Mesh generation

5 Volumetric power source generation with Serpent

6 OpenFOAM case setup

7 ResultsAshkhen Nalabndyan Beamer slides template 2012-08-27 2 / 25

Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Aim and Motivation

The aim of this tutorial is to demonstrate the coupling mechanismbetween OpenFOAM and a neutron transport software Serpent.

The topic of the tutorial is motivated by the need to find newapproaches for tight coupling of neutron kinetics to thermalhydraulics for liquid fueled power plants.

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Prerequisites

The tutorial is developed for the OpenFOAMv1806 and Serpent2.0.The later is developed at the VTT Finalnd and can be obtained ondemand.

To maximize benefits from the tutorial some prior experience withOpenFOAM is necessary.

It is also suggested to take a look at Serpent documentation [2,3].

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Heat generation and heat transfer in nuclear fuel

Nuclear fuel is composed of heave fissile actinide elements such asU-235, U-233, Th-232.

The proccess responsible for heat generation if nuclear fission, e.g.

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Test Case

Cylindrical liquid fuel element, d=6 cm, l=20 cm

Inlet, outlet, walls

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

The buoyantBoussinesqPimpleFoam solver

buoyantBoussinesqPimpleFoam is a transient heat transfer solver forincompressible, turbulent flow with natural convection.

OFv1806

run

cd \$FOAM_SOLVERS

tree heatTransfer/buoyantBoussinesqPimpleFoam

buoyantBoussinesqPimpleFoam.C

createFields.H

Make

files

options

pEqn.H

TEqn.H

UEqn.H

1 directory, 7 filesAshkhen Nalabndyan Beamer slides template 2012-08-27 6 / 25

Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

The buoyantBoussinesqPimpleFoam.C

Description: Transient solver for buoyant, turbulent flow of incompressiblefluids.Uses the Boussinesq approximation:rho k=(1-beta(T-T ref))rho k = the effective (driving) kinematic densitybeta = thermal expansion coefficient [1/K]T = temperature [K]T ref = reference temperature [K]Valid when:beta(T - T ref)/rho ref << 1# include fvCFD.H# include singlePhaseTransportModel.H# include turbulentTransportModel.H# include radiationModel.H# include fvOptions.H# include pimpleControl.HAshkhen Nalabndyan Beamer slides template 2012-08-27 7 / 25

Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

The buoyantBoussinesqPimpleFoam.C

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

The buoyantBoussinesqPimpleFoam.C

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

TEqn.H

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Generating identical mesh for OpenFOAM and Serpent

The mesh is generated using the ANSYS CFX inbuilt mesher.Alternatively, one can use the gmesh software.

Generate the mesh file and export it in .msh format

Copy to any OpenFOAM case directory, e.g.$FOAM TUTORIALS/heatTransfer/buoyantSimpleFoam/buoyantCavity

Type: fluentMeshToFoam inputfilename.msh

Run: checkMesh

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Mesh generation

Do: (Serpent2.0 is the user case dir for Serpent)

cp points /home/asnalb/DTU/Courses/ChalmersOSCFD/Serpent2.0

cp faces /home/asnalb/DTU/Courses/ChalmersOSCFD/Serpent2.0

cp neighbour /home/asnalb/DTU/Courses/ChalmersOSCFD/Serpent2.0

cp owner /home/asnalb/DTU/Courses/ChalmersOSCFD/Serpent2.0

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Description of Serpent input

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Description of Serpent input

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Coupling interface card

Serpent Multiphysics interface is a set of routines implemented at thesource code level and intended to easily bring in temperature anddensity distributions into OpenFOAM and exporting volumetic powerin a format supported by coupled codes such as OpenFOAM.

There are 9 interfaces in total, and type 9 is based on theOpenFOAM file format and supports FOAM field and mesh files.

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

Running Serpent: volpower file

In the Serpent case dir the following files should exist:inpTs.txtrhos.txtmaterials.txtpointsneighbourfacesownersss2Serpentmeshimport.py

Execution: ./sss2 inp

a volpower file is generated in the case folder, which defines avolpower object belonging to Foam volScalarField class.

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

FOAM case

OF v1806

cd $FOAM_RUN

cp -r $F OAM_TUTORIALS/heatTransfer/buoyantBoussinesqPimpleFoam/BernardCells .

mv BernardCells testCase tree

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

0/volpower

Put the inputfile.msh in the case directory and generate mesh by fluentMeshToFoam.msh command. Alternatively, replace the constant/polymesh directory with the one generated for Serpent. \\

Open the volpower file generated by Serpent, and add boundaries from constant/polymesh/bounsaries files to the end of it:

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

system/fvoptions

FoamFile

{

version 2.0;

format ascii;

class dictionary;

location "system";

object fvOptions;

}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

heatSource

{

type FieldSource;

active yes;

selectionMode all;

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

system/fvoptions

FieldSourceCoeffs

{

fieldNames (h);

sourceFieldNames (volpower);

}

However, if one tries to run the case, an error message appears thatFieldSource is not a recognized Foam source type. Thus, we have to addit.

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

fieldSource library

Copyright (C) Timo Niemi, Riku Tuominen 2018 VTT Technical Research Centre of Finland Ltd\\

fieldDource.C

namespace Foam

{

namespace fv

{

defineTypeNameAndDebug(FieldSource, 0);

addToRunTimeSelectionTable

(

option,

FieldSource,

dictionary

);

}

}

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

fieldSource library

The structure of the the fieldSource folder

tree fieldSource

fieldSource.C

fieldSource.H

lnInclude

fieldSource.C -> ../fieldSource.C

fieldSource.H -> ../fieldSource.H

Make

files

options

Compile by :wcleanwmake

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

system/controlDict

libs ("libFieldSource.so");

application buoyantBoussinesqPimpleFoam;

startFrom latestTime;

startTime 0;

stopAt endTime;

endTime 10;

deltaT 0.1;

writeControl runTime;

writeInterval 1;

purgeWrite 0;

writeFormat ascii;

writePrecision 6;

writeCompression off;

timeFormat general;

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

iterate.py

This tutorial describes only one-through iteration between Serpentand OpenFOAM. However, it might be of interest to be able toiterate the process for a specified OpenFOAM timestep. A pythonscript is currently in development to allow to do this.

So, as it can be noticed, first the parameter x and n are specified; theiteration will either stop when the temperature variation within thecell from one iteration to another is less than x%, or when the nnumber of iterations is done.

A corresponding while loop has to be chosen to do that.

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Introduction Theory The buoyantBoussinesqPimpleFoam solver Mesh generation Volumetric power source generation with Serpent OpenFOAM case setup Results

T and volpower

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