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

Temperature Gradient at Wall

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

Like Tree3Likes
  • 2 Post By santos
  • 1 Post By santos

Reply
 
LinkBack Thread Tools Display Modes
Old   June 23, 2009, 13:48
Default Temperature Gradient at Wall
  #1
Member
 
Sven Winkler
Join Date: May 2009
Posts: 70
Rep Power: 8
sven is on a distinguished road
I am simulating a laminar channel flow with heated walls. To calculate y nusselt number I first want to calculate the temperature gradient at the wall. Unfortunately I couldnt find some function similar to "WallGradU" which is able to calculate the wall temperature gradient, like "WallGradU" does it for the velocity gradient. Has anyone an idea how I could get the temperature gradient out of OpenFOAM? Can the "WallGradU" function be edited to get the temperature gradient?
sven is offline   Reply With Quote

Old   June 23, 2009, 22:18
Default
  #2
Member
 
Jitao Liu
Join Date: Mar 2009
Location: Jinan , China
Posts: 64
Rep Power: 8
awacs is on a distinguished road
Hi sven,

I am interested in this problem too. I am new to OpenFOAM. I want to simulate the filling process of non-newtonian fluids into a heated cavity.The energy equation was added to the interFoam solver to calculate the temperature field.
At the heated wall:

1) The temperature of non-newtonian fluid is assumed equal to the wall's (in my case,the thermal conductivity of the wall is much larger than that of the non-newtonian fluid ).

2) A coupled solver such as chtMultiRegionFoam can be created to solve this problem. Combination of heatConductionFoam and interHeatFoam (interFoam with energy equation) for conjugate heat transfer between a solid region and fluid region.

I am working on the second part.

If there is any development, please let me know.

Best regards,
Jitao

Last edited by awacs; July 20, 2009 at 04:42.
awacs is offline   Reply With Quote

Old   June 24, 2009, 04:27
Default
  #3
Senior Member
 
santos's Avatar
 
Jose Luis Santos
Join Date: Mar 2009
Location: Portugal
Posts: 213
Rep Power: 9
santos is on a distinguished road
Send a message via Skype™ to santos
Hi Sven,

Make a copy of wallGradU, replace U with T, volVectorField with volScalarField and dimensionedVector with dimensionedScalar. It should work!

Regards,
Jose Santos

Quote:
Originally Posted by sven View Post
I am simulating a laminar channel flow with heated walls. To calculate y nusselt number I first want to calculate the temperature gradient at the wall. Unfortunately I couldnt find some function similar to "WallGradU" which is able to calculate the wall temperature gradient, like "WallGradU" does it for the velocity gradient. Has anyone an idea how I could get the temperature gradient out of OpenFOAM? Can the "WallGradU" function be edited to get the temperature gradient?
EleCr and Hamoon like this.
santos is offline   Reply With Quote

Old   June 24, 2009, 12:16
Default
  #4
Member
 
Sven Schweikert
Join Date: Jun 2009
Posts: 38
Rep Power: 8
svens is on a distinguished road
Hi Santos - thanks for your reply.

I have the same intention like sven and tried your advise.
Sadly I received some errors while creating the new wallGradT:

Line 80 - error: Expected primary-expressions before '(' token
Line 83 - error: 'scalar' is not a class of namespace

PHP Code:
#include "fvCFD.H"

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

int main(int argcchar *argv[])
{
    
timeSelector::addOptions();
    
#include "setRootCase.H"
#   include "createTime.H"
    
instantList timeDirs timeSelector::select0(runTimeargs);
#   include "createMesh.H"

    
forAll(timeDirstimeI)
    {
        
runTime.setTime(timeDirs[timeI], timeI);
        
Info<< "Time = " << runTime.timeName() << endl;

        
IOobject Theader
        
(
            
"T",
            
runTime.timeName(),
            
mesh,
            
IOobject::MUST_READ
        
);

        
// Check U exists
        
if (Theader.headerOk())
        {
            
mesh.readUpdate();

            
Info<< "    Reading T" << endl;
            
volScalarField T(Theadermesh);

            
Info<< "    Calculating wallGradT" << endl;

            
volScalarField wallGradT
            
(
                
IOobject
                
(
                    
"wallGradT",
                    
runTime.timeName(),
                    
mesh,
                    
IOobject::NO_READ,
                    
IOobject::AUTO_WRITE
                
),
                
mesh,
                
dimensionedScalar
                
(                                                 <- line 80
                    
"wallGradT",
                    
T.dimensions()/dimLength,
                    
scalar::zero                              <- line 83
                
)
            );

            
forAll(wallGradT.boundaryField(), patchi)
            {
                
wallGradT.boundaryField()[patchi] =
                    -
T.boundaryField()[patchi].snGrad();
            }

            
wallGradT.write();
        }
        else
        {
            
Info<< "    No T" << endl;
        }
    }

    
Info<< "End" << endl;

    return 
0;

I am an absolutely beginner and I didn't find a solution for these errors so far.
About some additional help I would be really helpful.

Thanks a lot & regards
svens
svens is offline   Reply With Quote

Old   June 24, 2009, 12:20
Default
  #5
Senior Member
 
santos's Avatar
 
Jose Luis Santos
Join Date: Mar 2009
Location: Portugal
Posts: 213
Rep Power: 9
santos is on a distinguished road
Send a message via Skype™ to santos
Replace scalar::zero with 0 and all should be well.

Regards,
Jose Santos
Hamoon likes this.
santos is offline   Reply With Quote

Old   June 24, 2009, 15:23
Default
  #6
Member
 
Sven Schweikert
Join Date: Jun 2009
Posts: 38
Rep Power: 8
svens is on a distinguished road
It works! Perfect - thanks so much.
svens is offline   Reply With Quote

Old   July 23, 2010, 05:04
Default
  #7
Senior Member
 
n/a
Join Date: Sep 2009
Posts: 198
Rep Power: 7
deji is on a distinguished road
Question: I am able to compute the mean temperature gradient at a specified patch of my choosing. The is essentially 3D, hence the I have a 2D plane wall temperature gradient. Can anyone give me any feedback or advice as to how I can average the temperature gradient along a wall direction, so that I end with an output that comprises two columns such as: x dTmean/dn
x1 *****
x2 *****

Thanks.

Deji
deji is offline   Reply With Quote

Old   November 1, 2010, 18:25
Default
  #8
Member
 
Join Date: Nov 2009
Posts: 48
Rep Power: 7
farhagim is on a distinguished road
Hello Jitao,

I would like to know if you were successful with your implementation. I am interested in such a coupled solver ( combination of heatConductionFoam and interHeatFoam ). I would be so grateful if you can help me.

Thanks,

Mehran


Quote:
Originally Posted by awacs View Post
Hi sven,

I am interested in this problem too. I am new to OpenFOAM. I want to simulate the filling process of non-newtonian fluids into a heated cavity.The energy equation was added to the interFoam solver to calculate the temperature field.
At the heated wall:

1) The temperature of non-newtonian fluid is assumed equal to the wall's (in my case,the thermal conductivity of the wall is much larger than that of the non-newtonian fluid ).

2) A coupled solver such as chtMultiRegionFoam can be created to solve this problem. Combination of heatConductionFoam and interHeatFoam (interFoam with energy equation) for conjugate heat transfer between a solid region and fluid region.

I am working on the second part.

If there is any development, please let me know.

Best regards,
Jitao
farhagim 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
Wall Normal Temperature Gradient Daniel Tanner FLUENT 5 May 3, 2009 00:01
how to get the change of temperature of a wall shoeb CD-adapco 2 November 30, 2004 14:44
Multicomponent fluid Andrea CFX 2 October 11, 2004 05:12
Help,UDF for temperature derivatives in wall. jwt FLUENT 0 August 17, 2002 08:17
Direct calculation of temperature gradient J.W.Ryu FLUENT 5 December 27, 2001 07:39


All times are GMT -4. The time now is 02:54.