Vacuum Initial condiction

club68512 · March 11, 2010, 07:46

hello, every one
i have a problem

does the Initial condiction can set Vacuum ?

thanks

MuxaB · March 12, 2010, 00:04

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, 02:07

Quote:

Originally Posted by MuxaB

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

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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March 11, 2010, 07:46	Vacuum Initial condiction	#1
club68512 New Member liang liam Join Date: Nov 2009 Location: Taiwan Posts: 28 Rep Power: 16	hello, every one i have a problem does the Initial condiction can set Vacuum ? thanks

March 12, 2010, 00:04		#2
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 336 Rep Power: 18	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?

April 6, 2010, 10:20		#4
MuxaB Senior Member michael barkhudarov Join Date: Mar 2009 Location: Sante Fe, New Mexico, USA Posts: 336 Rep Power: 18	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..