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-   -   Differents fluids separated by wall (http://www.cfd-online.com/Forums/fluent/43381-differents-fluids-separated-wall.html)

phil January 18, 2007 03:43

Differents fluids separated by wall
 
Hello everyone,

I have different fluids (lets says a dozen!), all of them separated by a wall. So I have 12 fluids separated by 11 wall. There is heat exchange in these 11 walls.

The fluids are totally differents : water, oil, anything you want... and I want to use gravity. At this step, I have a first issue : (1) I can't define different operating density for each fluid, can I ?

Now one of these 12 fluids requires "solidification/melting" because there is a phase change at 330K. For this fluid there is no velocity inlet and outflow, this fluid can't go away, there is only walls around it.

I need "gravity" to compute natural convection in the liquid phase. If I want to use the Boussinesq hypothesis, I redefine the material, and I give a value for the Boussinesq density, and the thermal expansion coefficient "beta" (so the operating density will not apply for this fluid, am I right ?)

But now, I have an issue when I use Boussinesq with solidification/melting, I can give only one value for the density. But the density of the solid phase is not the same than the liquid phase (there is 10% volume expansion between liquid/solid) !!!

(2) Is there no way to use Boussinesq for the liquid phase, and a different density for the solid phase ?

Can anyone insure me that it is not possible to do that with fluent ? or tell me if I missed something...

Thanx a lot.


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