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-   -   dsmcFoam - rhoN zero yet a particle source ? (http://www.cfd-online.com/Forums/openfoam/79313-dsmcfoam-rhon-zero-yet-particle-source.html)

archymedes August 19, 2010 11:06

dsmcFoam - rhoN zero yet a particle source ?
 
Hi everybody,

I i've tried to do some dsmc simulations through a microchannel injecting gas in a bigger volume.
The big volume has an outlet at the other end.

Strange observations is, it seems like as if the volume is filled with gas from the outlet side.

basically i've only set the pressures ( rhoN ) at the microchannel inlet and the volume outlet. the pressure at the outlet is zero, yet there is a high concentration of dsmcParticles around it.

obviously I am not defining an vacuum outlet here but despite setting rhoN,rhoM and dsmcRhoN to zero, what should I do to make it an outlet ?

boundaryU, linearKE, internalE and momentum are set to "calculated"

Thanks for any response
archy

archymedes September 6, 2010 12:50

It seems as the amount of particles injected to the system by the outlet depends on the boundaryT Temperature at outlet.
If set to Room temperature you can clearly see particles being injected to the source, if you set it to 1e-12 it sucks out particles as expected from an vacuum outlet.

I would like to set it to zeroGradient but cant ( Error) so how do you treat your boundaryT conditions for an vacuum outlet ?

Thanks,
Archy


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