CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > CFX

Problem with rotating impeller in centrifugal pump

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

Reply
 
LinkBack Thread Tools Display Modes
Old   October 4, 2013, 02:49
Default Problem with rotating impeller in centrifugal pump
  #1
New Member
 
Join Date: Oct 2013
Posts: 3
Rep Power: 3
Kalybre is on a distinguished road
Hello,

I have work with Ansys but not too much with CFX. I am having a problem with a centrifugal pump. I think my problem is due to the boundary conditions or perhaps the interface, I am not sure. I have check the rest of the thread but I couldn't find an answer and the tutorial is only for an impeller, not for a complete pump.

I describe my set up in the enclosed file.


All advise is grateful
Attached Files
File Type: docx Centrifugal pump Setup.docx (52.5 KB, 41 views)

Last edited by Kalybre; October 4, 2013 at 07:31.
Kalybre is offline   Reply With Quote

Old   October 4, 2013, 06:06
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,671
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
The document is not readable. Please do not post it on links, just post it on the forum.
ghorrocks is offline   Reply With Quote

Old   October 4, 2013, 08:07
Default
  #3
New Member
 
anonymous
Join Date: Jan 2013
Posts: 3
Rep Power: 4
filippogalli is on a distinguished road
From my point of view there are two errors:

- For the impeller define the rotation as "Domain motion: rotating" and not as "Rotating Wall"
- Domain Interface: Interface Model-Frame Change/Mixing Model: here you have to use either Stage or Frozen Rotor otherwise this can not work.
filippogalli is offline   Reply With Quote

Old   October 4, 2013, 08:41
Default
  #4
New Member
 
Join Date: Oct 2013
Posts: 3
Rep Power: 3
Kalybre is on a distinguished road
Quote:
Originally Posted by filippogalli View Post
From my point of view there are two errors:

- For the impeller define the rotation as "Domain motion: rotating" and not as "Rotating Wall"
- Domain Interface: Interface Model-Frame Change/Mixing Model: here you have to use either Stage or Frozen Rotor otherwise this can not work.
For the impeller I only have the options:
- No slip wall (this is the only that allow add rotary velocity)
- Free slip wall
- Specific shear

Perhaps I should define the DEFAULT DOMAIN rotating?
Kalybre is offline   Reply With Quote

Old   October 4, 2013, 08:56
Default
  #5
New Member
 
anonymous
Join Date: Jan 2013
Posts: 3
Rep Power: 4
filippogalli is on a distinguished road
I don't understand what your default domain is!

You should define different domains for each component (impeller, volute, inlet pipe) and then define the stationary domains as stationary (volute and inlet pipe) and the rotating domain (runner) as rotating with your RPM set and the no slip wall condition for hub, shroud and blades.

If you do this right the default domain will disappear as it normal contains only parts that have not defined in another domain.
filippogalli is offline   Reply With Quote

Old   October 8, 2013, 05:32
Default
  #6
New Member
 
Join Date: Oct 2013
Posts: 3
Rep Power: 3
Kalybre is on a distinguished road
Quote:
Originally Posted by filippogalli View Post
I don't understand what your default domain is!

You should define different domains for each component (impeller, volute, inlet pipe) and then define the stationary domains as stationary (volute and inlet pipe) and the rotating domain (runner) as rotating with your RPM set and the no slip wall condition for hub, shroud and blades.

If you do this right the default domain will disappear as it normal contains only parts that have not defined in another domain.
Yes, you were right, I had defined the impeller like sub-domain, for that I didn't have th options that you told me.

Now I have defined 3 different domains: 2 stationary and one rotating (impeller).
The Domain interface: Frame Change/Mixing Model : Frozen Rotor ( y tried with stage too), between : Inlet pipe - impeller & impeller - Casing.
With these should work, but I have obtained the results on the enclosed picture.

Why the impeller is stationary? I can't understand it.
Attached Images
File Type: jpg CFX Results.jpg (86.3 KB, 28 views)
Kalybre is offline   Reply With Quote

Old   October 8, 2013, 05:44
Default
  #7
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,671
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Have you read the documentation about rotating frames of reference? There are many different ways of doing this - you need to understand the assumptions behind the models to understand the results.
ghorrocks is offline   Reply With Quote

Old   July 26, 2014, 17:42
Default
  #8
New Member
 
Bilal Waseem
Join Date: Mar 2014
Posts: 11
Rep Power: 3
billy7590 is on a distinguished road
I am having similar issues.
When I use frozen rotor interface, CFX asks for pitch setting as well. My inlet pipe side of interface has a different mesh than the mesh on impeller side of interface. Does that have an adverse effect ??
billy7590 is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to Create the Rotating Reference Frame of a MRF Problem in DM wrt to an Interface Zev Xavier FLUENT 11 October 14, 2014 08:46
Rotating Impeller Naith FloEFD, FloWorks & FloTHERM 22 November 5, 2012 09:53
Pump Impeller aboazm ANSYS 0 November 2, 2012 17:51
Want Impeller Driven Fluid Flow: What Inlet and Outlet BC to use for Centrifugal Pump Zev Xavier FLUENT 2 May 9, 2012 08:52
Need Help, rotating Impeller ajinsan CFX 6 December 15, 2010 05:30


All times are GMT -4. The time now is 02:51.