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turbulentHeatFluxTemperature heat capacity of what material?

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Old   May 7, 2014, 13:22
Default turbulentHeatFluxTemperature heat capacity of what material?
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Andrew Somorjai
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Hello everyone,

Looking at the source for the turbulentHeatFluxTemperatureFvPatchScalarField class at

https://github.com/OpenFOAM/OpenFOAM...hScalarField.H

The heat capacity at constant pressure is listed

Code:
hotWall
        {
            type            turbulentHeatFluxTemperature;
            heatSource      flux;        // power [W]; flux [W/m2]
            q               uniform 10;  // heat power or flux
            alphaEff        alphaEff;    // alphaEff field name;
                                         // alphaEff in [kg/m/s]
            Cp              Cp;          // Cp field name; Cp in [J/kg/K]
            value           uniform 300; // initial temperature value
        }
If I had a box full of air with a wall made of steel transferring heat would I use the heat capacity of air or steel. I don't suppose the steel part would even matter for the simulation but I'm just not sure if it's simply the air Cp that would be needed. If it's for steel then how come there's no length requirement for the conductor (from the formula for thermal conductivity)?

thanks to anyone for clearing it up.
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Old   May 20, 2014, 11:19
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Joachim Herb
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With the turbulentHeatFluxTemperatureFvPatchScalarField boundary conditions you transfere a certain amount of heat (either defined as flux, a.k. power/area or total power for the whole surface) into the fluid. Heat conduction in the boundary is not considered, so the heat capacity is the one of the fluid. If you want to simulation also the solid and the heat conduction inside it, you have to go with the multi region solver (see the corresponding tutorias, e.g. heatTransfer/chtMultiRegionFoam etc.)
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Old   May 20, 2014, 16:16
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Andrew Somorjai
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Quote:
Originally Posted by jherb View Post
With the turbulentHeatFluxTemperatureFvPatchScalarField boundary conditions you transfere a certain amount of heat (either defined as flux, a.k. power/area or total power for the whole surface) into the fluid. Heat conduction in the boundary is not considered, so the heat capacity is the one of the fluid. If you want to simulation also the solid and the heat conduction inside it, you have to go with the multi region solver (see the corresponding tutorias, e.g. heatTransfer/chtMultiRegionFoam etc.)
Thank you, that's exactly what I was thinking too but I didn't know about the multi region solver.
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Old   May 20, 2014, 17:47
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Also have a look at this boundary condition:
https://github.com/OpenFOAM/OpenFOAM...hScalarField.H
This might also apply in your case.
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