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-   -   Vacuum Initial condiction (http://www.cfd-online.com/Forums/flow-3d/73568-vacuum-initial-condiction.html)

club68512 March 11, 2010 08:46

Vacuum Initial condiction
 
hello, every one
i have a problem

does the Initial condiction can set Vacuum ?


thanks

MuxaB March 12, 2010 01:04

voids can be assigned pressure and temperature, but without the use of a bubble model it does not make much difference for one-fluid incompressible flow. What is the application you are using it for?

club68512 March 12, 2010 03:07

Quote:

Originally Posted by MuxaB (Post 249653)
voids can be assigned pressure and temperature, but without the use of a bubble model it does not make much difference for one-fluid incompressible flow. What is the application you are using it for?


so the voids is air?
I don't know the void means,and how to use it.

i wanna use vapor started into a tube to condensation and I think the tube should not have any fluids at first. so i wanna set the tube as vacuum condiction at first.


thank you very much! you really help me many times!

MuxaB April 6, 2010 10:20

If you want to inject vapor into a vacuum, then a void model will not work. You will need to use the two-fluid model, with fluid #1 representing liquid phase and fluid #2 representing the vapor. The initial vacuum will have to approximated by the vapor at a low density.

You can then inject vapor (fluid #2) at a mesh boundary by specifying the velocity, density and temperature at it. As it condenses it will form fluid #1, liquid that is..

club68512 April 6, 2010 10:32

Quote:

Originally Posted by MuxaB (Post 253346)
If you want to inject vapor into a vacuum, then a void model will not work. You will need to use the two-fluid model, with fluid #1 representing liquid phase and fluid #2 representing the vapor. The initial vacuum will have to approximated by the vapor at a low density.

You can then inject vapor (fluid #2) at a mesh boundary by specifying the velocity, density and temperature at it. As it condenses it will form fluid #1, liquid that is..

thank you for your reply!

The initial vacuum will have to approximated by the vapor at a low density. I don't know that means??...


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