CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

outlet boundary condition for compressor modeling

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 6, 2009, 11:07
Default outlet boundary condition for compressor modeling
  #1
New Member
 
mazda
Join Date: Jul 2009
Posts: 7
Rep Power: 17
siamak1424 is on a distinguished road
hi friends, i have several questions.
i want to solve a 3D blade of a compressor with LES of FLUENT.
boundary condition I useed is "VELOCITY INLET" for inlet . is it correct?
for the outlet, which bounadry condition I must use? is "PRESSURE OUTLET" correct?
for using "PRESSURE OUTLET", is minimum distance from outlet plane and trailing edge necessary? and how "gauge pressure" set?

i am so thankful for your attention.
siamak1424 is offline   Reply With Quote

Old   August 6, 2009, 11:38
Default
  #2
New Member
 
Ryan
Join Date: Jul 2009
Location: Windsor
Posts: 9
Rep Power: 17
RyGuy is on a distinguished road
Hello,

From my knowledge, you should not use pressure outlet with velocity inlet. I believe that you should be using the pressure inlet boundary condition. When using the pressure inlet condition, you would need to define the temperature as well for the compressible flow.

I read in the Fluent manual that when using velocity inlet condition, it should be used with the outflow condition and this would be well suited for incompressible flow.

I assume you would want your model to incorporate compressibility effects considering you are modeling a compressor, is this correct?

Gauge pressure is defined as:
p_absolute = p_gauge + p_operating

So you should define the gauge pressure accordingly to this equation

If this does not help you try looking in the Manual for more information...

Sincerely,
Ryan
RyGuy is offline   Reply With Quote

Old   August 8, 2009, 03:29
Default
  #3
New Member
 
mazda
Join Date: Jul 2009
Posts: 7
Rep Power: 17
siamak1424 is on a distinguished road
thanks ruyguy. i am thankful for your attention. a have another question about this. is there any restriction for the distance of outlet plane from trailing edge and distance of inlet plane from leadin edge?
siamak1424 is offline   Reply With Quote

Old   August 8, 2009, 05:55
Default
  #4
New Member
 
Join Date: Jul 2009
Posts: 4
Rep Power: 17
alekpopob is on a distinguished road
For the in-duct compressed flow problems, pressure inlet and pressure outlet is suitable. Anyway others also possible. for example, massflow inlet and pout. But it will be more difficult to reach convergence.

If the problem is to solve airfoil, pressure far field condition is also reasonable.

But Vin and Pout is just for compressed flow? Noway....
alekpopob is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
inlet and outlet boundary condition for turbomachinery solution siamak1424 OpenFOAM 2 August 15, 2009 11:14
outlet boundary condition khalid FLUENT 0 April 3, 2007 15:01
Outlet boundary condition CN FLUENT 6 May 22, 2005 09:37
Outlet velocity boundary condition Jay FLUENT 4 December 15, 2002 08:27
outlet Boundary condition Tol na Deen CFX 2 July 23, 2002 08:49


All times are GMT -4. The time now is 10:47.