Modelling of chemical batch reactor for the course CFD with - - PowerPoint PPT Presentation

Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial

Modelling of chemical batch reactor for 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 available techniques in OpenFOAM. Generation of Mesh using cfMesh. Physical Modelling of rotation is done by using MRF and mesh motion. Implementation of scalar transport equation to check mixing statistics.

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 3 / 16

Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial

Geometry

Figure: Geometry of batch reactor

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 4 / 16

Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial

cfMesh

cfMesh is a open source library for automatic mesh generation. It uses inside out meshing strategy. supports all recent versions of OpenFOAM and foam extend It supports four meshing Work flows. carteisanMesh can be run using MPI parallelisation.

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 5 / 16

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, ftr and .stl files. Generates mesh based on the settings given in meshDict file two mandatory settings are required to initialize meshing.

maxCellSize surfaceFile

Various refinement settings are available.

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 6 / 16

Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial

Problems

Cannot generate Mesh if we have multiple disconnected domains. Will delete all the cells in the region which has less number of cells. Individual .stl files for surface and edge refinements.

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 7 / 16

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

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 8 / 16

Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial

Final Mesh

Figure: Final Mesh

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 9 / 16

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 mesh motion. MRF - equations are solved in multiple reference frame mesh motion- it includes mesh motion (Sliding mesh method)

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 10 / 16

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 extend simpleFoam + 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 chosen from AMI, GGI and mixing plane.

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 11 / 16

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 using constant/dynamicMeshDict. AMI interface is used between stator and rotor. pimpleDyMFoam is used. larger computational time.

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 12 / 16

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 time to check mixing statistics.

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 13 / 16

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 before

going to next step simpleFoam

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 14 / 16

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.

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 15 / 16

Contents Introduction Geometry cfMesh Modelling of rotation Implementaion of scalar transport equation Tutorial

That’s it

Thank you! Questions?

Rajukiran Antham Modelling of chemical batch reactor December 8, 2015 16 / 16