# Wrong boundary conditions?

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

August 25, 2011, 05:13
Wrong boundary conditions?
#1
New Member

Join Date: Aug 2011
Posts: 1
Rep Power: 0
Hello Foamers,

I want to simulate the flow through a heat exchanger and have already implemented the geometry in OpenFoam.
One part of the heat exchanger looks like the letter U. In this area I got the attached result. The picture shows a slide through the pipe.
I am confused about the flow pattern, because I expected an increase of the velocity at the edge of the curved tube.
Can this be caused by the boundary conditions?
Simulation with: SimpleFoam + k-epsilon for turbulence

Boundary conditions:

U:
boundaryField
{

inlet
{
type fixedValue;
value uniform (1.088250128 0 0);
}

outlet
{
}

Walls
{
type fixedValue;
value uniform (0 0 0);
}

symmetric
{
type symmetryPlane;
}

frontAndBack
{
type empty;
}
}

p:
dimensions [0 2 -2 0 0 0 0];

internalField uniform 101.3;

boundaryField
{
inlet
{
}

outlet
{
type fixedValue;
value uniform 101.3;
}

Walls
{
}

symmetric
{
type symmetryPlane;
}

frontAndBack
{
type empty;
}
}

The frontAndBack-Patch is not in use anymore.

Thanks for your help and good ideas,

Thomas
Attached Images
 Simulation.jpg (54.4 KB, 47 views)

 August 28, 2011, 07:17 #2 New Member   Alex Join Date: Apr 2011 Location: München Posts: 13 Rep Power: 7 Hello Thomas, I am a beginner in OpenFOAM but for me the boundary conditions look okay and I also agree to you that the results look strange. I would would expect an increase of the velocity. The only thing is, I would change the pressure outlet boundary condition to "\$internalField" than "uniform 101.23". What is your convergence criteria and the "symmetric" part of your geometry? Regards, Alex

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Thomas P. Abraham Main CFD Forum 20 July 7, 2013 05:05 cves OpenFOAM Bugs 3 May 3, 2010 03:38 mactech001 CFX 6 November 15, 2009 22:25 lyang Main CFD Forum 0 September 19, 1999 18:29 Jan Ramboer Main CFD Forum 11 August 16, 1999 08:59

All times are GMT -4. The time now is 18:11.

 Contact Us - CFD Online - Top