CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM

Problem with alpha.water > 1 in multiphase flow

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 9, 2022, 11:54
Default Problem with alpha.water > 1 in multiphase flow
  #1
New Member
 
Marc Baydoun
Join Date: Aug 2022
Location: paris
Posts: 1
Rep Power: 0
mbaydoun is on a distinguished road
Hello everyone!
I'm new to this community and I'm a beginner in openfoam programming so bare that in mind. I'm simulating a gas generation from a porous media into a liquid bassin. The two domains are resolved via two previously developed openfoam codes:
porous media code: Handles the generation of gas and the transport of gas governed by Darcy equation
liquid bassin code: Handles fluid flow (based on compressible flow)


I developed a code for the interface boundary conditions for:alpha.water, U and P


The U and P conditions are the based on pressurePermeableAlphaInletOutletVelocity and prghPermeableAlphaTotalPressureFvPatchScalarField that are used in the dam break tutorial.


For the alpha.water condition, I want to precise that when the gas pressure in the porous medium surpasses that of the neighbouring cell in the liquid bassin, the gas bubble can flow and thus:


if(p_Porous>p_Bassin):

{
this->refValue()=0.9;
this->valueFraction()=1,0;
}


else
{
this->refValue()=1.0;
this->valueFraction()=0,0;
}



However, the alpha.water during calculations becomes greater than 1 and, at some point, the simulation diverges because of a "negative initial temperature".


What is wrong with the conditions specified? what might be the source of the error?


Any help is appreciated.


Thanks




initial conditions for alpha.water:


boundaryField
{
walls
{
type zeroGradient;
}
atmosphere
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}
interface
{
type coupledmixedAlphaMultiphaseBC; (developed library)
neighbourFieldName poreMedia;
value uniform 1;
}
}



For the U file:


boundaryField
{
walls
{
type fixedValue;
value uniform (0 0 0);}

atmosphere
{
type pressureInletOutletVelocity;
value uniform (0.0 0.0 0.0);
}

Interface
{
type coupledMixedVelocityMultiphaseBC ; (developed library)
value uniform (0 0 0);
alphaMin 0.01;

}





and for the P file:


boundaryField
{
walls
{
type fixedFluxPressure;
}
atmosphere
{
type totalPressure;
p0 uniform 101325;
U U;
phi phi;
rho rho;
psi none;
gamma 1;
value uniform 101325;
}


Interface
{
type mycoupledmixedPressureMultiphaseBC; (developed library)
value uniform 101325;
alphaMin 0.01;

}
mbaydoun is offline   Reply With Quote

Reply

Tags
alpha.water, multiphase boundary wall, multiphase flow

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
unable to run dynamic mesh(6dof) and wave UDF shedo Fluent UDF and Scheme Programming 0 July 1, 2022 18:22
Free Surface Ship Flow timfranke OpenFOAM Running, Solving & CFD 322 March 3, 2021 10:04
Free surface issues with interDyMFoam for hydroturbine oumnion OpenFOAM Running, Solving & CFD 0 October 6, 2017 15:05
Modeling unsteady multiphase flow in porous media - convergence problem Vaibhav Kumar Main CFD Forum 1 July 22, 2012 05:32
Multiphase flow problem lentil FLUENT 1 November 30, 2005 05:39


All times are GMT -4. The time now is 08:04.