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-   -   Have problem with 2 phase porous media (http://www.cfd-online.com/Forums/fluent-multiphase/124339-have-problem-2-phase-porous-media.html)

Juun October 2, 2013 11:16

Have problem with 2 phase porous media
 
I am doing a simple filter simulation, shown in the pic.


http://i52.photobucket.com/albums/g3...Untitled-1.png

Phase 2 (particle) will stop and accumulate on the left hand side.



Phase 1 (mixture gas) goes through porous media, wall surface reaction happens at the same time on the porous media.



Problems


1. As there is no ‘wall’, I setup volumetric reaction in porous media, Am I doing this correct?



2. How to simulate particle accumulation?


And the last one problem is that the solver runs ok without multiphase (that is only has mixture gas) … but when I switch it to 2 phases, there is error, saying



Divergence detected in AMG solver: phase-1-species-0
Divergence detected in AMG solver: phase-1-species-1
Divergence detected in AMG solver: phase-1-species-2
Divergence detected in AMG solver: phase-1-species-3
Primitive Error at Node 0: floating point exception
Primitive Error at Node 1: floating point exception
Primitive Error at Node 2: floating point exception
Primitive Error at Node 3: floating point exception


The species fractions settings are the same in both cases (with and without multiphase)


Does anyone have any idea about these problems? Many thanks.

sampathevs October 3, 2013 00:39

What is your inlet condition ?

Try increasing the pressure relaxation factor and by decreasing the momentum and volume fraction relaxation factor

Divergence in AMG solver is because of URF's .

Did u define porous zone ?

Regards,
Sampath Emani

Juun October 3, 2013 07:44

Sampath, Thanks

inlet conditions:
velocity inlet for both phases, at 5 m/s (i chose random number, at this stage),
temperature default setting 300k
mass fraction (picked randomly for this stage)
species 0: 0
species 1: 0.1
species 2: 0.3
species 3: 0.5

phase 2 volume fraction 0.1

yes, I defined a porous zone. Do you mean if I have defined porous zone, particle accumulation will automatically appear?
-----------------------------------------------------
after I reduced some URFs, the error has gone... Thanks

Thanks a lot
Juun


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