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

heat transfer with OpenFoam

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

Like Tree2Likes

Reply
 
LinkBack Thread Tools Display Modes
Old   March 30, 2011, 02:25
Default
  #21
Senior Member
 
Join Date: Mar 2011
Posts: 155
Rep Power: 6
tH3f0rC3 is on a distinguished road
Hello,

I have another question to
-k=turbulent energy
-epsilon=dissipation
-nut=turbulent viscosity

I have to set up these files in the 0-file as boundary cinditions.
k and epsilon must have a value for the inlet surfaces. But how can I calculate these values?
And what is meant with the values
Cmu 0.09;
kappa 0.41;
E 9.8;
They are automatically set up as written above.

What do they mean?

Best Regards,
tH3f0rC3
tH3f0rC3 is offline   Reply With Quote

Old   March 30, 2011, 10:58
Default
  #22
New Member
 
Fatih
Join Date: Sep 2010
Location: Hamburg
Posts: 12
Rep Power: 6
ang_dipl_ing_fd is on a distinguished road
hi dirk,
may be this will help you

http://www.cfd-online.com/Wiki/Turbu...ary_conditions

the other values are default model coefficients which i would not change.
ang_dipl_ing_fd is offline   Reply With Quote

Old   March 30, 2011, 11:34
Default
  #23
Senior Member
 
Join Date: Mar 2011
Posts: 155
Rep Power: 6
tH3f0rC3 is on a distinguished road
Hi,

thank you, that's a very good link! :-)
tH3f0rC3 is offline   Reply With Quote

Old   March 31, 2011, 03:34
Default
  #24
Senior Member
 
Join Date: Mar 2011
Posts: 155
Rep Power: 6
tH3f0rC3 is on a distinguished road
In the description is written that k and epsilon must be specified for the inlet boundaries.
But how do I set up the walls or outlets?

The suggestion of ANSA is to set zeroGradient to walls and outlets. ANSA suggests this by outputting the file as an OpenFoam case. So i don't know if this is right.

Another question is how to set up inlet and outlet layers in nut. For walls I can use nutwallfunction but what shall I use for inlet and outlets.
The suggestion of ANSA in this case is also zeroGradient.

Best Regards,
tH3f0rC3

Last edited by tH3f0rC3; March 31, 2011 at 03:59.
tH3f0rC3 is offline   Reply With Quote

Old   March 31, 2011, 06:50
Default
  #25
New Member
 
Fatih
Join Date: Sep 2010
Location: Hamburg
Posts: 12
Rep Power: 6
ang_dipl_ing_fd is on a distinguished road
hi dirk,
i would use for k and epsilon:
...
outlet
{
type inletOutlet;
inletValue $internalField; // or you calculate with estimated values
value $internalField; // only a placeholder
}
...

and for nut:

"(inlet|outlet)" // so you specify inlet AND outlet at the same time
{
type calculated;
}

for walls you can use wall function for k and epsilon
"(wallA|wallB|wallC)"
{
type kqRWallFunction; // wall function for k, q and R
}

and

wall
{
type epsilonWallFunction;
}

This is for incompressible simulation!!!
If you are fluid is compressible than you have to set

type compressible::"Wall_Function";
ang_dipl_ing_fd is offline   Reply With Quote

Old   August 18, 2011, 11:55
Default
  #26
Member
 
A. Bernath
Join Date: Jun 2011
Location: Karlsruhe, Germany
Posts: 39
Rep Power: 6
derkermit is on a distinguished road
Quote:
Originally Posted by tH3f0rC3 View Post
Hi,

is there someone else, who understands the following error message?

Create time
Create mesh for time = 0

Reading g
Reading thermophysical properties
Selecting thermodynamics package hPsiThermo<pureMixture<constTransport<specieThe rmo<hConstThermo<perfectGas>>>>>
#0 Foam::error:rintStack(Foam::Ostream&) in "/data/caehgb.za/studienarbeit-di rk/work/OpenFoam_ParaView/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPOpt/libOpenFOA M.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/data/caehgb.za/studienarbeit-dirk/work /OpenFoam_ParaView/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 __restore_rt in "/lib64/tls/libc.so.6"
#3 Foam::hPsiThermo<Foam:ureMixture<Foam::constTran sport<Foam::specieThermo<F oam::hConstThermo<Foam:erfectGas> > > > >::calculate() in "/data/caehgb.za/stu dienarbeit-dirk/work/OpenFoam_ParaView/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPO pt/libbasicThermophysicalModels.so"
#4 Foam::hPsiThermo<Foam:ureMixture<Foam::constTran sport<Foam::specieThermo<F oam::hConstThermo<Foam:erfectGas> > > > >::hPsiThermo(Foam::fvMesh const&) in "/data/caehgb.za/studienarbeit-dirk/work/OpenFoam_ParaView/OpenFOAM/OpenFOAM-1.7 .1/lib/linux64GccDPOpt/libbasicThermophysicalModels.so"
#5 Foam::basicPsiThermo::addfvMeshConstructorToTable< Foam::hPsiThermo<Foam:ur eMixture<Foam::constTransport<Foam::specieThermo<F oam::hConstThermo<Foam:erfec tGas> > > > > >::New(Foam::fvMesh const&) in "/data/caehgb.za/studienarbeit-dirk /work/OpenFoam_ParaView/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPOpt/libbasicTher mophysicalModels.so"
#6 Foam::basicPsiThermo::New(Foam::fvMesh const&) in "/data/caehgb.za/studienar beit-dirk/work/OpenFoam_ParaView/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPOpt/lib basicThermophysicalModels.so"
#7 main in "/data/caehgb.za/studienarbeit-dirk/work/OpenFoam_ParaView/OpenFOAM/ OpenFOAM-1.7.1/applications/bin/linux64GccDPOpt/buoyantSimpleRadiationFoam"
#8 __libc_start_main in "/lib64/tls/libc.so.6"
#9 Foam::regIOobject::writeObject(Foam::IOstream::str eamFormat, Foam::IOstream: :versionNumber, Foam::IOstream::compressionType) const in "/data/caehgb.za/studi enarbeit-dirk/work/OpenFoam_ParaView/OpenFOAM/OpenFOAM-1.7.1/applications/bin/li nux64GccDPOpt/buoyantSimpleRadiationFoam"
Floating point exception
I got a similar error a few days ago when solving a heat-transfer-case. I got rid of it by not setting the temperature to 0 K anywhere
Maybe that helps someone...
derkermit is offline   Reply With Quote

Old   August 25, 2011, 10:42
Default Change pressure
  #27
New Member
 
Peter
Join Date: Feb 2011
Posts: 9
Rep Power: 6
Peter88 is on a distinguished road
You probably have a zero pressure at the internalField. Any how, I got the same message and it went away when I was changing the internal pressure and pressure at outlet.

Gr Peter
Peter88 is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Heat transfer problem seojaho CFX 6 May 6, 2010 00:32
Heat Transfer Coefficient los OpenFOAM Running, Solving & CFD 5 January 31, 2010 18:44
Which Heat transfer coeffcient to use? tengra FLUENT 1 May 1, 2009 13:49
No results for solid domain Gary Holland CFX 10 March 13, 2009 04:30
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 16:55


All times are GMT -4. The time now is 00:19.