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-   -   VOF transfer - multiphase flow (http://www.cfd-online.com/Forums/main/10730-vof-transfer-multiphase-flow.html)

karthik February 1, 2006 03:20

VOF transfer - multiphase flow
 
Dear Friends,

I am solving a multiphase flow problem. (study of Interaction between Molten metal and air).

Problem: Molten metal is pushing air when it i getting pumped in with high velocity. The have implemented VOF (VOLUME OF FRACTION ) - PLIC method to track the movement of molten metal.

I need to transfer the VOF value depending upon the velocity at which the molten metal pushes. The case happens like if the velocity is very high, I need to ensure that the molten metal is geting transfered in the direction of flow.

I am facing a logical problem in distributing the VOF of molten metal in all the three directions (I am solving a3D Problem).

N:B) I had referred Donor acceptor method , but it will consume lot of Computational efforts.

If possible, Suggest me some logical method to distribute the VOF value in 3D.

Thanks & Regards

Karthik

kharicha February 1, 2006 03:52

Re: VOF transfer - multiphase flow
 
I do not understand your problem:

"Problem: Molten metal is pushing air when it i getting pumped in with high velocity"....is this a problem ?

"I need to transfer the VOF value depending upon the velocity at which the molten metal pushes. The case happens like if the velocity is very high, I need to ensure that the molten metal is geting transfered in the direction of flow."

What does this mean ??? You have nothing to ensure, the calculation should do it....

But maybe you have solidification ?


karthik February 1, 2006 05:09

Re: VOF transfer - multiphase flow
 
Let me put like this,

I transfer water in the form of flux from one cell (source) to other cell (sink) through a face. The sink cell will get populated from all the 6 directions ( 6 faces of a 3D cell).

Because the sink cell cannot recieve or hold the quantity of VOF more than its volume (sink cell volume). So, I have to transfer the expelled amount ( more than the sink cell could hold) to the further neighbors.In what direction of neighbors i should transfer(distribute the water).

I don't think , only having the flow direction will give a solution for the above discussed case.

I am thinking of some tactical logic to do the above activity which will comply with physics of flow.

Hope i have made it clear Karicha.( Do not think of solidification). Treat this as an interaction between water and air.

Moreover, solution process can give only the value of VOF that gets populated in the sink cell for every time step as of now.


Jim_Park February 1, 2006 10:08

Re: VOF transfer - multiphase flow
 
If I understand this, it sounds as if you're trying to overfill the receptor cell in one time step.

If that's correct, I'd consider cutting the time step so that the receptor cell is filled - but not overfilled - in one time step.

Good luck!

karthik February 2, 2006 02:25

Re: VOF transfer - multiphase flow
 
Hey Jim,

Overfill is happening as a solution process. I need to avoid that situation by further distributing the overfill amount ( more than a cell to hold - volume of cell)to the neighboring cells of receptor cell without compromising the physics of flow.

cheers Karthik



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