backflow volume fraction

August 29, 2002, 04:33

I use the multiphase model,in the pressure outlet boundary condition,there is a "backflow volume fraction",i don't understand what's these means,maybe you can help me.Thanks for your help!!!

September 1, 2002, 11:47

the backflow vof is used only when there is a reverse flow at the outlet.your convergence would be faster if you give a reasonable value.

September 1, 2002, 21:09

thank you very much!another thing is how can get the backflow vof,may through the experiment?

September 2, 2002, 04:40

this value has to be intutively.when reverse flow is expected in your domain,then the value has to come from experiments

September 2, 2002, 19:44

your help is very useful,thank you very much.

maysmech · February 19, 2011, 07:29

Hi,
how can i set outlet volume fraction when set pressure outlet?
is it related to backflow?
regards.

VT_Bromley · February 19, 2011, 12:53

In regards to this.. could the backflow volume fraction be used to restrict the seondary phase from leaving the system at a pressure outlet?

maysmech · February 19, 2011, 14:32

Thanks,
So you mean if back flow volume fraction set to 1 only that phase can exit from that patch? What's your idea about above comments about backflow?

August 29, 2002, 04:33	backflow volume fraction	#1
fei Guest Posts: n/a	I use the multiphase model,in the pressure outlet boundary condition,there is a "backflow volume fraction",i don't understand what's these means,maybe you can help me.Thanks for your help!!!

September 1, 2002, 11:47	Re: backflow volume fraction	#2
sri Guest Posts: n/a	the backflow vof is used only when there is a reverse flow at the outlet.your convergence would be faster if you give a reasonable value.

September 1, 2002, 21:09	Re: backflow volume fraction	#3
fei Guest Posts: n/a	thank you very much!another thing is how can get the backflow vof,may through the experiment?

September 2, 2002, 04:40	Re: backflow volume fraction	#4
sri Guest Posts: n/a	this value has to be intutively.when reverse flow is expected in your domain,then the value has to come from experiments

September 2, 2002, 19:44	Re: backflow volume fraction	#5
fei Guest Posts: n/a	your help is very useful,thank you very much.

February 19, 2011, 07:29		#6
maysmech Senior Member Join Date: Jan 2010 Posts: 347 Blog Entries: 2 Rep Power: 17	Hi, how can i set outlet volume fraction when set pressure outlet? is it related to backflow? regards.

February 19, 2011, 12:53		#7
VT_Bromley New Member Michael Join Date: Nov 2010 Posts: 23 Rep Power: 16	In regards to this.. could the backflow volume fraction be used to restrict the seondary phase from leaving the system at a pressure outlet?

February 19, 2011, 14:32		#8
maysmech Senior Member Join Date: Jan 2010 Posts: 347 Blog Entries: 2 Rep Power: 17	Thanks, So you mean if back flow volume fraction set to 1 only that phase can exit from that patch? What's your idea about above comments about backflow?

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