modelling of chemical batch reactor for the course cfd ...hani/kurser/os_cfd_2015/... · modelling...
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Modelling of chemical batch reactorfor the course
CFD with OpenSource Software
Rajukiran Antham
Applied Mechanics/Fluid Dynamics,Chalmers University of Technology,
Gothenburg, Sweden
December 8, 2015
Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 1 / 16
Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Contents
Introduction
Geometry
cfMesh
Modelling of rotation
scalar transport equation
Tutorial
Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 2 / 16
Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Introduction
Modelling of Chemical batch reactor using availabletechniques in OpenFOAM.
Generation of Mesh using cfMesh.
Physical Modelling of rotation is done by using MRFand mesh motion.
Implementation of scalar transport equation to checkmixing statistics.
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Geometry
Figure: Geometry of batch reactor
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
cfMesh
cfMesh is a open source library for automatic meshgeneration.
It uses inside out meshing strategy.
supports all recent versions of OpenFOAM and foamextend
It supports four meshing Work flows.
carteisanMesh can be run using MPI parallelisation.
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Input geometry and meshDict file
File formats suggested for input geometry are fms, ftrand .stl files.
Generates mesh based on the settings given inmeshDict filetwo mandatory settings are required to initializemeshing.
maxCellSizesurfaceFile
Various refinement settings are available.
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Problems
Cannot generate Mesh if we have multipledisconnected domains.
Will delete all the cells in the region which has lessnumber of cells.
Individual .stl files for surface and edge refinements.
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Individual patches vs single patch
a) with individual patches b) with single patch
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Final Mesh
Figure: Final Mesh
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Modelling of rotation
This is done by using two techniques MRF and meshmotion.
MRF - equations are solved in multiple reference frame
mesh motion- it includes mesh motion (Sliding meshmethod)
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
MRF
• Implemented in different ways in OpenFOAM and foam extend.
OpenFOAM foam extendsimpleFoam + fvOptions MRFsimpleFoam + MRFZones
fvOptions is present in system/fvOptions
MRFZones is present in constant/MRFZones
Does not account for interaction between stator and rotor.
type of mesh interface between stator and rotor can be chosenfrom AMI, GGI and mixing plane.
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
mesh motion
Accounts for the transient stator-rotor interaction.
mesh motion is defined usingconstant/dynamicMeshDict.
AMI interface is used between stator and rotor.
pimpleDyMFoam is used.
larger computational time.
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Implementaion of scalar transport equation
∂C
∂t+
∂(uiC)
∂xi=
∂(DC · ∂C∂xi
)
∂xi+ s
C is concentration and s is source term.
DC is diffusion term.
Tracer is implemented after the solution is converged.
Nacl is used as tracer.
Probes are located at point locations to plot concentration over timeto check mixing statistics.
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Tutorial MRF
run
cd ProjectMRF
mergeMeshes stator rotor
rm -r rotor
cd stator
rm -r constant/polyMesh
mv 0.005/polyMesh constant/
transformPoints -scale ’(0.001 0.001 0.001)’
setSet
topoSet
• boundary file and boundary conditions should to be changed beforegoing to next step
simpleFoam
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Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial
Tutorial AMI
It is similar to MRF, since same interface and same mesh is used.
mesh motion is defined in dynamicMeshDict file.
It is time consuming so tutorial is not done here.
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