Heat source in porous zone
 

Hello Foamers,

I want to model a flow with a porous zone which works well using rhoPorousSimpleFoam in OF 1.6.x.
In a next step, I want to add a heat sink to the porous medium. Is it a good idea to use (and probably extend) the porousZone machinery to this end or is it a better idea to do something on the solver level?
A possible approach is to modify the hEqn with an appropriate source term and multiply it with a field value which corresponds to 1 in the porous region and 0 elsewhere, but this seems not to be very elegant.
What do you think?

Best regards,
-Thomas

hallo Thomas,
i want as well to add a heat source to the porous zone like you, and want to ask how you handle this?

kind regards,
Dima

great job guys
looks like what i am looking for is implemented in OF 2.0.0

best regards, Dima

What theory model are you using?

I have the same problem, but I have resolved it applying a modify to hentalpy equation, changing the laplacian therm

at the moment i am using just test models, like pitzDaily or a simple inlet outlet channel (tube) with a pZone in it

i was going to resolve it by applying a modify to hEqn as well, changing the source term -> not finished at the moment, just at the beginning

in the new version of OpenFoam there is a thermalPorousZone model (fixedTemperature)

in my further work i will try to add a new model something like fixedEnthaly
but my knowledge of the OF source structure is low at the moment, so i hope there is not a lot of change to do

Hi Dima,

Did you succeed in using the fixedTemperature model for thermalPorousZone ?

When I try it on the rhoPorousMRFSimpleFoam tutorial, it gives me strange behaviour with T (near 0 after the thermal porousZone) and with rho (limited at 1.5 by fvSolution also after the porousZone).

I get this behaviour with different values for the temperature coefficient (even 0).

Could you tell me if you experienced this model ?

Best regards,
Fabien

Hi Fabien,

i didn't succeed in using the angledDuct case too, the same problems occur

so something might be wrong to the calculation (hDiag and hSource) in fixedTemperature.C
or the (rho) settings in the fvSolution ...

but i am not familiar with that at the moment

regards, Dima

hello,

i changed the fixedTemperature.C

...
forAll(zones, zoneI)
{
const labelList& cells = mesh.cellZones()[zones[zoneI]];

forAll(cells, i)
{
hDiag[cells[i]] += 1/rate*V[cells[i]]*rho[cells[i]];

hSource[cells[i]] += V[cells[i]]*rho[cells[i]]*T_;

}
}

it looks much better now, but not correct at all
would be nice if someone who knows how to handle this could reply

regards, Dima

Hi Dima,
I'm workin on thermal porous media too.
I checked the OF 2.1 and the fixedTemperature eqn. source is fixed with Cp:

I did not check if is correct yet...
I'm trying also to implement non-fixedT, maybe a powerLaw, but I don't know which kind of law I can use.
Do you know something about it?

Hi Andrea,

Did you manage to implement a non-fixedT law in the thermalPorousZone ?

If yes, would you mind sharing it with me ?

I tried by myself but I'm stuck with hDiag and hSource, I don't unserstand how it works with hEqn.

No matter what I try, I got weird results in the temperature field (mostly very low or very high T field).

Thanks,
Fabien

Hi Fabien,
no I did not implement it... what law did you use for it?
I'm also interesting to add different thermal conductivity (kappa field) just inside the porous medium.
I'm thinking at: kappa_eff = porosity*kappa_porous_medium + (1-porosity)*kappa_fluid.
Do you know something about this?

Thanks

Andrea

Hello Andrea,

did you managed to calculate an effective conductivity as function of the porosity?

I am so intrested in this subject!

thanks a lot,
Nadine