CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM

Temperature-dependent properties and mass conservation in porousExplicitSourceReactin

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

LinkBack Thread Tools Display Modes
Old   October 26, 2010, 06:46
Default Temperature-dependent properties and mass conservation in porousExplicitSourceReactin
Robertas N.
Join Date: Mar 2009
Location: Kaunas, Lithuania
Posts: 53
Rep Power: 10
r08n is on a distinguished road
Hi *,

I modified the 'porousExplicitSourceReactingParcelFoam' to include heat sources in the energy equation and set up a very simple simulation: a box filled with pure N2, no mass flows (U=uniform(0,0,0)) and a uniform field of the heat source, in order to raise the temperature; that's just for testing purposes -- the setup will get more complex in the future. The solver uses
the polynomial coefficients defined in constant/thermo.incompressiblePoly for temperature-dependent parameters: density, heat capacity @p=const and some other. As the temperature rises, the density gets lower, therefore, the total mass in the box (calculated as m=sum_over_cells(rho(cell)*V(cell))) diminishes, but the pressure stays constant. Of course, this setup is incorrect -- it must use heat capacity @ constant volume, not @ constant pressure, and assume the compressible fluid (gas in this case). I have a few questions:
1) Is it possible to obtain somewhere the polynomial coefficients for heat capacity at constant volume? Where are the data in thermo.incompressiblePoly taken from? I couldn't find any references -- ChemKin, maybe?
2) Why does the pressure stay constant in the current simulation? Isn't 'porousExplicitSourceReactingParcelFoam' meant to be compressible solver?

The modified energy equation looks like this:
fvm::ddt(rho, h) + mvConvection->fvmDiv(phi, h)
- fvm::laplacian(turbulence->alphaEff(), h)
pWork() + parcels.Sh() + radiation->Sh(thermo) + Q_heat

All the terms on the RHS are zero, except for Q_heat, which is defined as a volScalarField with constant power density (in W/m^3).
Did I overlook something? Thank you for any pointers, hints, keywords for searching...
r08n is offline   Reply With Quote


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
Constant velocity of the material Sas CFX 15 July 13, 2010 08:56
Simulation of a single bubble with a VOF-method Suzzn CFX 18 October 2, 2009 04:18
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 08:07
Mass Properties of Axial Fan Bladegen Katamish CFX 2 May 12, 2009 05:39
Two-Phase Buoyant Flow Issue Miguel Baritto CFX 4 August 31, 2006 12:02

All times are GMT -4. The time now is 10:31.