information regarding void fraction.

August 4, 2006, 09:38

hi all, can anyone help me how to view void fractions for flow through a cavitation tunnel? and can the cfx mesh be refined manually?? regards, deep

motahar · May 20, 2011, 03:33

Hi friends,
I'm simulating a tube with water flow.
The tube encounters boiling near the wall.
I intend to calculate 'void fraction versus enthalpy' along the channel.
Can you help me how to calculate void fraction?

I'm in an emergency condition.
Waiting for your comments!!!

Thanks Everybody

ghorrocks · May 20, 2011, 06:11

That sounds like the volume fraction of the vapour. This is a normal variable accessible in the post processor.

motahar · May 20, 2011, 06:46

Thanks ghorrock for your comment.

So you mean there is no difference between 'void fraction' and 'volume fraction'?

Yes I have seen volume fraction in the post processor, but I didn't know they are the same.

Again thanks a lot for your guide.

All the best

ghorrocks · May 21, 2011, 07:58

I do not know how you are defining void fraction - but you would think void fraction is the same as gas volume fraction.

motahar · May 21, 2011, 12:18

Hi ghorrocks,
Yes you're right. I mean what you said.
I've worked in single phase for more than 1 year.
But I'm beginner in multiphase flow.
Can you help me how to define multiphase in CFX-Pre?
Thanks

August 4, 2006, 09:38	information regarding void fraction.	#1
cfx user Guest Posts: n/a	hi all, can anyone help me how to view void fractions for flow through a cavitation tunnel? and can the cfx mesh be refined manually?? regards, deep

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May 20, 2011, 03:33		#2
motahar New Member M. A. Join Date: Jul 2010 Posts: 27 Rep Power: 15	Hi friends, I'm simulating a tube with water flow. The tube encounters boiling near the wall. I intend to calculate 'void fraction versus enthalpy' along the channel. Can you help me how to calculate void fraction? I'm in an emergency condition. Waiting for your comments!!! Thanks Everybody

May 20, 2011, 06:11		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	That sounds like the volume fraction of the vapour. This is a normal variable accessible in the post processor.

May 20, 2011, 06:46		#4
motahar New Member M. A. Join Date: Jul 2010 Posts: 27 Rep Power: 15	Thanks ghorrock for your comment. So you mean there is no difference between 'void fraction' and 'volume fraction'? Yes I have seen volume fraction in the post processor, but I didn't know they are the same. Again thanks a lot for your guide. All the best

May 21, 2011, 07:58		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	I do not know how you are defining void fraction - but you would think void fraction is the same as gas volume fraction.

May 21, 2011, 12:18		#6
motahar New Member M. A. Join Date: Jul 2010 Posts: 27 Rep Power: 15	Hi ghorrocks, Yes you're right. I mean what you said. I've worked in single phase for more than 1 year. But I'm beginner in multiphase flow. Can you help me how to define multiphase in CFX-Pre? Thanks