[mizzou]

Hi,

Does anybody know how to compare the results of 2D simulation with experimental results? In case of mine, I simulated the Air and Water two phase flow in a horizontal tube and I am going to validate the results with experimental ones which is basically 3D. For example, what is the relation for the velocity of the phases (Water and Air) in experiment and simulation?

Thanks for any feedback in advance.

[ekrumrick]

Originally Posted by mizzou

Hi,

Does anybody know how to compare the results of 2D simulation with experimental results? In case of mine, I simulated the Air and Water two phase flow in a horizontal tube and I am going to validate the results with experimental ones which is basically 3D. For example, what is the relation for the velocity of the phases (Water and Air) in experiment and simulation?

Thanks for any feedback in advance.

Hi Mizzou,

You can take a look at this papers:

- Numerical Modelling of Two-Dimensional Gas-Liquid Flow Structures - Vladimir Evgenyevich Vershinin, Rodion Mikhaylovich Ganopolsky, Vitaly Olegovich Polyakov.

-Comparison of Two-Phase Pipe Flow in OpenFOAM with a Mechanistic Model Adrian M Shuard, Hisham B Mahmud and Andrew J King.


These are not comparisons against experimental data but against the mechanistical models of Taitel and Dukler (Vershinin) and Petalas and Aziz (Shuard).


Best regards,





Ezequiel

[mizzou]

Originally Posted by ekrumrick

Hi Mizzou,

You can take a look at this papers:

- Numerical Modelling of Two-Dimensional Gas-Liquid Flow Structures - Vladimir Evgenyevich Vershinin, Rodion Mikhaylovich Ganopolsky, Vitaly Olegovich Polyakov.

-Comparison of Two-Phase Pipe Flow in OpenFOAM with a Mechanistic Model Adrian M Shuard, Hisham B Mahmud and Andrew J King.


These are not comparisons against experimental data but against the mechanistical models of Taitel and Dukler (Vershinin) and Petalas and Aziz (Shuard).


Best regards,





Ezequiel

Dear Ezequiel,

I really appreciate for introducing those papers. I already checked that articles very fast. I think those are really helpful for my case. Many thanks for your help.

Best,

[ekrumrick]

Originally Posted by mizzou

Dear Ezequiel,

I really appreciate for introducing those papers. I already checked that articles very fast. I think those are really helpful for my case. Many thanks for your help.

Best,

Here is a small contribution from my part: https://www.academia.edu/30000859/PR...FLUID_DYNAMICS

Regards,

[mizzou]

Originally Posted by ekrumrick

Here is a small contribution from my part: https://www.academia.edu/30000859/PR...FLUID_DYNAMICS

Regards,

Dear Ezequiel,

Mant thanks for the link. Very nice work! I have a few questions:
1) in which cases (which flow patterns) you used interFoam and for which of interDyMFoam?
2) Why you could not capture annular flow? (is there any particular reason for that?)
3) There is no information about phase fraction (alpha). Which boundary conditions for alpha are used?

Also, if you don't mind, could you please send the blockMeshDict of your 3D case (half of the pipe)?

Thank you,
Milad

[sharonyue]

Im also validating the 2D and 3D simulations with experiments. Well, actually I started from 3D first...The 3D results show good agreement with the experimental data. I will get back to you later after my 2D simulation completes.

My test solver is twoPhaseEulerFoam. Experiments are from Diaz et al. CEJ. 2008. V139.

[ekrumrick]

Originally Posted by mizzou

Dear Ezequiel,

Mant thanks for the link. Very nice work! I have a few questions:
1) in which cases (which flow patterns) you used interFoam and for which of interDyMFoam?
2) Why you could not capture annular flow? (is there any particular reason for that?)
3) There is no information about phase fraction (alpha). Which boundary conditions for alpha are used?

Also, if you don't mind, could you please send the blockMeshDict of your 3D case (half of the pipe)?

Thank you,
Milad

Thank you, Milad,

I apologize for the delay to answer.

I will try to answer your questions as best as I can:

1) All 3D cases were run first with a coarse mesh utilizing interFoam, and then were refined up to two levels utilizing interDyMFoam, I did not simulate the finer meshes with interFoam because of the great computational time required.

2) I am not completely sure about the exact reason for not being able to capture annular flow, I assume that it was required to simulate a greater length and/or time, or perhaps, the conditions simulated were so close to the limit of the transition zone that the real flow was not annular. It is also important to understand that the mechanistic map was constructed within certain limits of experimental data and it is not expected to predict 100% of flows perfectly, mainly in the transition regions.

3) For the inlet conditions, alpha is 0.5, as it is easier to specify the superficial velocities this way. I did not track alpha after achieving developed flow conditions, may be this could be to better complete my work.

As for the blockMeshDict, I attach a version I have stored in my computer, if you are a little more patient, I can attach the final version in a couple weeks (sorry for the comments are in Spanish).

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.4.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

a1 5; //cantidad de celdas de lado para el cuadrado, dirección x
a2 10; // idem dirección y
a3 4; //cantidad de celdas de ancho para el semicírculo

c 1100; //cantidad de celdas de profundidad en z

d1 -24; //semilado del cuadrado interior
d2 24; //idem anterior
d3 0; //x simetria

e1 -28.284271247; //semilado del cuadrado exterior, que se transforma en círculo (r/sqrt(2))
e2 28.284271247; //idem anterior

f1 0; //semilongitud del cilindro en z
f2 5000; //idem anterior

g1 -40; //radio del círculo
g2 40; //radio del círculo

h1 -32; // punto de los círculos inferior/superior para simetría
h2 32;

j1 -37.5877048314363;
j2 -13.6808057330267;
j3 13.6808057330267;

convertToMeters 0.001;


vertices
(

    ($d1 $d1 $f1) //0 Los primeros ocho puntos corresponden al cuadrado pequeño
    ($d3 $d1 $f1) //1
    ($d3 $d2 $f1) //2
    ($d1 $d2 $f1) //3

    ($d1 $d1 $f2) //4
    ($d3 $d1 $f2) //5
    ($d3 $d2 $f2) //6
    ($d1 $d2 $f2) //7

    ($e1 $e1 $f1) //8 Los siguientes ocho puntos corresponden al "cuadrado" grande, que luego se transforma en el círculo exterior
    ($d3 $g1 $f1) //9
    ($d3 $g2 $f1) //10
    ($e1 $e2 $f1) //11

    ($e1 $e1 $f2) //12
    ($d3 $g1 $f2) //13
    ($d3 $g2 $f2) //14
    ($e1 $e2 $f2) //15

    (-40 0 0) //16
    (-24 0 0) //17
    (  0 0 0) //18
    (-40 0 5000) //19
    (-24 0 5000) //20
    (  0 0 5000) //21
    
);

blocks
(
    hex (17 18 2 3 20 21 6 7) ($a1 $a1 $c) simpleGrading (1 1 1) //Cuadrado interior
    hex (0 1 18 17 4 5 21 20) ($a1 $a1 $c) simpleGrading (1 1 1) //Cuadrado interior

    hex (16 17 3 11 19 20 7 15) ($a3 $a1 $c) simpleGrading (1 1 1) //Semicírculo izquierdo
    hex (8 0 17 16 12 4 20 19) ($a3 $a1 $c) simpleGrading (1 1 1) //Semicírculo izquierdo

    hex (8 9 1 0 12 13 5 4) ($a1 $a3 $c) simpleGrading (1 1 1) //Semicírculo inferior

    hex (2 10 11 3 6 14 15 7) ($a3 $a1 $c) simpleGrading (1 1 1) //Semicírculo superior

);

edges
(

arc  8 16 ($j1 $j2 $f1) //Arco izquierdo anterior
arc 16 11 ($j1 $j3 $f1) //Arco izquierdo anterior
arc 12 19 ($j1 $j2 $f2) //Arco izquierdo posterior
arc 19 15 ($j1 $j3 $f2) //Arco izquierdo posterior

arc 9 8 ($d1 $h1 $f1) 
arc 13 12 ($d1 $h1 $f2)

arc 11 10 ($d1 $h2 $f1)
arc 15 14 ($d1 $h2 $f2)

);

boundary
(
    inlet_gas
    {
        type patch;
        faces
        (
            ( 2  3 11 10)
        (18 17  3  2)
        (17 16 11  3)
        );
    }
    inlet_oil
    {
        type patch;
        faces
        (
            (0 8 16 17)
            (1 9  8  0)
            (1 0 17 18)
        );
    }
    outlet_gas
    {

        type patch;
        faces
        (
            ( 6 14 15  7)
        (20 21  6  7)
        (19 20  7 15)
        );
    }
    outlet_oil
    {
        type patch;
        faces
        (
            (20 19 12  4)
            (12 13  5  4)
            ( 4  5 21 20)
        );
    }
    walls
    {
        type wall;
        faces
        (
            ( 8  9 13 12)
            ( 8 12 19 16)
        (16 19 15 11)
        (10 11 15 14)
        );
    }

    center
    {
        type symmetryPlane;
        faces
        (
            ( 2 10 14  6)
        (18  2  6 21)
            ( 1 18 21  5)
            ( 1  9 13  5)
        );
    }

);
mergePatchPairs
(
);


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

[mizzou]

Dear Ezequiel,

Thanks for the response and I appreciate for the attached code. I've just executed the blockMeshDict, but it did not work unfortunately. I would be so grateful if you could please send the final version once you can.

Thank you,

[ekrumrick]

Dear Milad,

I apologize again for my delay to answer. I hope you could solve the problems with this dictionary.

I am sorry for the misunderstanding, I started working with OF2.4, then moved to 3.0 and didn't change the head of the file.

The uploaded blockMeshDict works fine with OF 3.0.