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-   -   Incompressible Ideal Gaz in a closed system - Help (http://www.cfd-online.com/Forums/fluent/48913-incompressible-ideal-gaz-closed-system-help.html)

JB July 31, 2008 07:53

Incompressible Ideal Gaz in a closed system - Help
 
Hey everyone,

Can you think of any example where it can be relevant to use the Incompressible Ideal Gaz density formulation together with a closed system, and run a transient simulation where you heat up the system?

I'm just curious (I've tried it, it doesn't crash, but my results do not make any sense: some mass seem to disapear from my closed system, and ALL my particles are moving towards the cold reagion, i.e. no recirculation... what's happening??)

Thanks a lot for your insight. /JB

Emmanuel Resch July 31, 2008 14:56

Re: Incompressible Ideal Gaz in a closed system -
 
prob something to do with the boundaries... how do you have them set?

JB August 1, 2008 04:16

Re: Incompressible Ideal Gaz in a closed system -
 
my test case is very simple: it's a square (2d model). 3 walls out of 4 are adiabatic. the 4th wall has a fixed temperature. I initialize the solution with an homogemeous lower temperature, and then run a transient analysis.

The tank heats up, but the velocity results do not make any sense to me.

Again, maybe it's just dumb to use IIG density formulation in a closed tank. But once again, I'd like to understand what's happening... do I need to go through a 500 page book for that, or do you guys have an OK simple explanation for me?

Thanks /JB


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