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Unknown temperature increase in cube (OpenFoam)- Help is welcomed |
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April 11, 2017, 12:21 |
Unknown temperature increase in cube (OpenFoam)- Help is welcomed
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#1 |
New Member
Sergio López Sánchez
Join Date: Mar 2017
Posts: 4
Rep Power: 9 |
Good afternoon.
I am a student from Industrial Engineering and I am doing my degree project with OpenFoam. I am new in this world. My idea was to make a cube of air and insert (as boundaries conditions) a floor at 270 K (Kelvin), a ceiling at 330 K and the rest a 300 K. The solver I am using is buoyantPimpleFoam (compressible case). Firstly, when I simulate it, it appears a temperature gradient through the height of the cube. However, I want to insert an air flow (input) because the aim of the project is an HVAC application. When I add to the velocity of floor condition U (0,1,0) [that is upwards], the temperature increases a lot and I don't know exactly why. Might it be due to the pressure increase? In addition, the simulation ended before and this message appeared: Code:
--> FOAM FATAL IO ERROR: wrong token type - expected Scalar, found on line 0 the word 'nan' file: C:/OpenFOAM/user-3.0.x/run/hotRoom/v9/system/data.solverPerformance.p_rgh at line 0. From function operator>>(Istream&, Scalar&) in file lnInclude/Scalar.C at line 93. FOAM exiting Thank you. ATTACHMENTS [/CODE]hotRoom with U velocity and Temperature increase.zip hotRoom without U.zip T.org file: Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 3.0.x | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; object T; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 0 0 1 0 0 0]; internalField uniform 300; boundaryField { floor { type fixedValue; value uniform 270; } ceiling { type fixedValue; value uniform 330; } fixedWalls { type zeroGradient; } } // ************************************************************************* // Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 3.0.x | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volVectorField; object U; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { floor { type fixedValue; value uniform (0 1 0); } ceiling { type fixedValue; value uniform (0 0 0); } fixedWalls { type fixedValue; value uniform (0 0 0); } } // ************************************************************************* // Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 3.0.x | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; object p_rgh; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [1 -1 -2 0 0 0 0]; internalField uniform 1e5; boundaryField { floor { type fixedFluxPressure; value uniform 1e5; } ceiling { type fixedFluxPressure; value uniform 1e5; } fixedWalls { type fixedFluxPressure; value uniform 1e5; } } // ************************************************************************* // |
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April 13, 2017, 18:03 |
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#2 |
Senior Member
Join Date: Sep 2013
Posts: 353
Rep Power: 21 |
You have one inlet and no outlet. The simulation hence crashes. Pumping air into a room without an outlet can only lead to compression of that air. and hence a temperature and pressure increase. This becomes unstable very fast and pressure and temperature reach unphysical values.
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April 29, 2017, 17:20 |
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#3 | |
New Member
Sergio López Sánchez
Join Date: Mar 2017
Posts: 4
Rep Power: 9 |
Quote:
And how do I do that? Which conditions? |
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Tags |
hvac, openfoam |
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