Challenge

Week 11 - Simulation of Flow through a pipe in OpenFoam

SSwasthika D.S23 Nov 2021

CFD MATLAB

Aim:

To simulate flow through a circular pipe in openFoam
To write a MATLAB program to automate the generation of blockMeshDict filr for the circular pipe
To validate the simulation results using Hagen-Poiseulle's equation for fully devoloped flow

Given Data & Assumed Data

Reynolds number (Re)=2100

Diameter(D)=8mm

Wedge Angle=2.5degree

Length(L)=200mm

Density(`rho`)=995kg/m^3

Viscocity(`mu`)=8.97e-4

Hagen-Poiseullis Equation: Poiseulli's equation describes about the pressure drop in the floe due to the viscosity of the fluid and

Assumption

Incompressible flow
Incompressible flow
Newtonian fluid
Laminar flow
Steady flow
Cylindrical Symmetry
No gevitational Effect
Fully Devoloped Flow
No Roughness Facto

MatLab main code

clear all
close all
clc

L=200;
Re=2100;
D=8;
theta=2.5;
rho=997;
R=D/2;
mu=8.97e-4;

nx=50;
ny=1;
nz=500;

file = blockMesh(R,theta,L,nx,ny,nz);

Mat Lab function code

function [f1] = blockMesh(R,theta,L,nx,ny,nz)
f1 = fopen('blockMeshDict','W');
%introduction of the file
fprintf(f1,  '/*--------------------------------*- C++ -*----------------------------------*\n' );
fprintf(f1,' =========                 |n');
fprintf(f1,' \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox n');
fprintf(f1,'  \\    /   O peration     | Website:  https://openfoam.org n');
fprintf(f1,'   \\  /    A nd           | Version:  8 n');
fprintf(f1,'    \\/     M anipulation  |n');
fprintf(f1,'\*---------------------------------------------------------------------------*/n');
fprintf(f1,'FoamFile n');
fprintf(f1,'{n');
fprintf(f1,'  version     2.0; n');
fprintf(f1,'format      ascii; n');
fprintf(f1,'class       dictionary; n');
fprintf(f1,'object      blockMeshDict;n');
fprintf(f1,'}n');
fprintf(f1,'// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // n');
fprintf(f1,'n');
fprintf(f1,'convertToMeters 0.01;n');
fprintf(f1,'n');
fprintf(f1,'verticesn');

%Vertices of the wedge geometry
fprintf(f1,'(n');
fprintf(f1,'    (0 0 0) // Vertex 0 n');
fprintf(f1,'    (0 %f %f) // Vertex 1 n', R*cosd(theta/2),-R*sind(theta/2));
fprintf(f1,'    (0 %f %f) // Vertex 2 n', R*cosd(theta/2),R*sind(theta/2));
fprintf(f1,'    (%d 0 0) // Vertex 3 n', L);
fprintf(f1,'    (%d %f %f) // Vertex 4 n', L,R*cosd(theta/2),-R*sind(theta/2));
fprintf(f1,'    (%d %f %f) // Vertex 5 n', L,R*cosd(theta/2),R*sind(theta/2));
fprintf(f1,');n');

%BLOCKS
fprintf(f1,'blocks n');
fprintf(f1,'(n');
fprintf(f1,'   hex(0 1 2 0 4 5 3)(%d %d %d)simle grading(0.1 1 10)n',nx,ny,nz);
fprintf(f1,');n');

%Edges
fprintf(f1,'n');
fprintf(f1,'edges n');
fprintf(f1,'(n');
fprintf(f1,'   arc 1 2 (0 %d 0) n',R);
fprintf(f1,'   arc 4 5 (%d %d 0) n',L,R);
fprintf(f1,');n');

%Boundary
fprintf(f1,'n');
fprintf(f1,'boundary n');
fprintf(f1,');n');
%Axis
fprintf(f1,'axis n');
fprintf(f1,'{ n');
fprintf(f1,'  type empty; n');
fprintf(f1,'  facesn');
fprintf(f1,'(n');
fprintf(f1,'   (0 3 3 0) n');
fprintf(f1,'   );n');
fprintf(f1,'   }n');
fprintf(f1,'n');

%Inlet
fprintf(f1,'inletn');
fprintf(f1,'{ n');
fprintf(f1,'    type patch; n');
fprintf(f1,'    faces n');
fprintf(f1,'    (n');
fprintf(f1,'    ( 0 0 2 1) n'); 
fprintf(f1,'     );n');
fprintf(f1,'     }n');
fprintf(f1,'n');

%Wall
fprintf(f1,'  wall n');
fprintf(f1,'  {');
fprintf(f1,'    type wall; n');
fprintf(f1,'    faces n');
fprintf(f1,'    (n');
fprintf(f1,'    ( 2 5 4 1) n'); 
fprintf(f1,'     );n');
fprintf(f1,'     }n');
fprintf(f1,'n');

%Outlet
fprintf(f1,'  outlet n');
fprintf(f1,'  {');
fprintf(f1,'    type patch; n');
fprintf(f1,'    faces n');
fprintf(f1,'    (n');
fprintf(f1,'    ( 3 4 5 3) n'); 
fprintf(f1,'     );n');
fprintf(f1,'     }n');
fprintf(f1,'n');

%Front Side
fprintf(f1,'  front n');
fprintf(f1,'  {');
fprintf(f1,'    type wedge; n');
fprintf(f1,'    faces n');
fprintf(f1,'    (n');
fprintf(f1,'    ( 0 3 5 2) n'); 
fprintf(f1,'     );n');
fprintf(f1,'     }n');
fprintf(f1,'n');

%Back
fprintf(f1,'  back n');
fprintf(f1,'  {');
fprintf(f1,'    type wedge; n');
fprintf(f1,'    faces n');
fprintf(f1,'    (n');
fprintf(f1,'    ( 0 1 4 23) n'); 
fprintf(f1,'     );n');
fprintf(f1,'     }n');
fprintf(f1,'n');
fprintf(f1,');n');
%End
fprintf(f1,'n');
fprintf(f1,'mergePatchPairs n');
fprintf(f1,'(n');
fprintf(f1,');n');
fprintf(f1,'n');
fprintf(f1,'// ************************************************************************* /');
end

blockMeshDict

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 0.001;

vertices
(
    (0 0 0)//Vertex0
    (0 3.999048 -0.087260)//Vertex1
    (0 3.999048 0.087260)//Vertex2
    (200 0 0)//Vertex3
    (200 3.999048 -0.087260)//Vertex4
    (200 3.999048 0.087260)//Vertes5
    
);

blocks
(
    hex (0 1 2 0 3 4 5 3) (50 1 500) simpleGrading (0.1 1 1)
);

edges
(
	arc 1 2 (0 4 0)
	arc 4 5 (200 4 0)
);

boundary
(
    axis
    {
        type empty;
        faces
        (
            (0 3 3 0)
        );
    }
    inlet
    {
        type patch;
        faces
        (
            (0 0 2 1)
            
        );
    }
    wall
    {
        type wall;
        faces
        (
            (2 5 4 1)
            
        );
    }
    outlet
    	(
    		(3 4 5 3)
    	);
    }
    front
    {
    	type wedge;
    	faces
    	(
    		(0 3 5 2)
    	);
    }
    back
    {
         type wedge;
         faces
         (
         	(0 1 4 3)
         );
    }


);

mergePatchPairs
(
);

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

ControlDict

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     icoFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         0.2;

deltaT          0.00005;

writeControl    timeStep;

writeInterval   20;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;


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

Boundary Condetion

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    axis
    {
        type            empty;
    }

    inlet
    {
        type            zeroGradient;
    }

    wall
    {
        type            zeroGradient;
    }
    outlet
    {	type            fixedValue;
        value           uniform 10;
    }
    front
    {
    	type            wedge;
    }
    back
    	type            wedge;
    	
    }
}

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

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volVectorField;
    object      U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 1 -1 0 0 0 0];

internalField   uniform (0.50929 0 0);

boundaryField
{
    axis
    {
        type            empty;
        
    }

    inlet
    {
        type            fixedValue;
        value           uniform(0.50929 0 0 );
    }

    wall
    {
        type            fixedvalue;
        value            uniform (0 0 0);
    }
    outlet
    {
        type            inletOutlet;
        inletValue      uniform (0.50929 0 0);
        value            uniform (0.50929 0 0);
    }
    front
    {
    	type            wedge;
    }
    back
    {
    	type            wedge;
    }
    
}

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

Post Processing Results

velocity at inlet

Velocity at outlet

Pressure at inlet

Presuure at outlet

Week 11 - Simulation of Flow through a pipe in OpenFoam

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