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Pierre Mathieu May 21, 2010 05:43

Searching for a multispecies solver with buoyant dispersion

I want to simulate the injection of helium into air in a garage, at constant temperature. I used the reactingFoam solver adding the gravity effect (rho*g) in the UEqn.

The point is that I can't see any buoyancy effects on my results : HE and air are mixing like if there was no difference of density effect between species and I don't understand why...
This effect is very important for my simulation because after a while the injection is turned down in order to observe the dispersion of helium.

Have I to modify the scalar transport equation? Is an other solver better for my case?

I've seen another way using alpha, like in the twoLiquidMixingFoam solver, but I don't know if I can adapt it to my simulation because even if I have two species to transport, I have only one phase.

Thank you in advance for your answers !


Pierre Mathieu May 26, 2010 04:21


If some of you is interested in my case, I think I found my problem :
reactingFoam resolves U equation with a constant density, so doesn't take into account variation of density in the flow due to mixing of species.
To solve this problem I am now running twoLiquidMixingFoam solver which calculates changes in density and return it to the velocity equation so that the changes of density impact on the flow.
I hope better results with this solver !

thekay May 26, 2010 08:07

Thank you for the update Pierre. Are your new results better?

Pierre Mathieu May 27, 2010 03:38

Hi Thekay,
No there not, and I don't understand why... I obtained quite the same results with both solvers.

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