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talib March 1, 2012 16:25

void fraction
 
I'm trying to simulate 2Phase, gas-solid flow.
I've defined void fraction to the 2ndary phase via "velovity inlet" bc, in eulerian model.
I'm getting a bizar result. The model is converged in terms of net mass flux and residuals. velocity distribution is physical and makes sense.
However, void fraction value is at least 2 orders of magnitude below the bc boundary.
I've tried to simulate steady and transient problems.
I've tried to solve even via mixture model.
All result in the same result. It seems that the granular fluid is being "pushed away" from the domain. eg. for transient problem, if initializing value of 0.05, the value close to the inlet region is 5e-4, whilst the region close to the outlet is maintained at the initializing value. the region of low VF value increases with time. namely, the granular phase is being pushed away towards the exit.

I hope I explained myself properly.
Thank you very much in advance.
Talib


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