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

Can CFX do CHT simulations with a solid domain rotating in a stationary fluid domain?

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

Like Tree1Likes
  • 1 Post By stumpy

Reply
 
LinkBack Thread Tools Display Modes
Old   January 7, 2010, 11:36
Default Can CFX do CHT simulations with a solid domain rotating in a stationary fluid domain?
  #1
New Member
 
Join Date: Dec 2009
Posts: 3
Rep Power: 7
acro is on a distinguished road
I tried to rotate a solid impeller in a stationary fluid domain. What's I am trying to do is that the solid impeller rotates by itself and pushes the surrounding fluid.

I set the the solid impeller as a rotating domain, and the fluid as a stationary domain. And tried various options for the interface between solid and fluid. But none of them worked.

Could anybody guide me? Thanks a lot.
acro is offline   Reply With Quote

Old   January 7, 2010, 13:20
Default
  #2
Senior Member
 
Attesz's Avatar
 
Attesz
Join Date: Mar 2009
Posts: 355
Rep Power: 8
Attesz is an unknown quantity at this point
Hi,

I think it will not working. You have do define the fluid as a rotating domain, to set to the flow tangencial velocity component. But why do you want to do your simulation this way? Wit rotating domain option, you can get very accurate results, with transient simulation you can set "Transient Rotor Stator" Frame Change model, which "rotates" the domain...

Attesz
Attesz is offline   Reply With Quote

Old   January 7, 2010, 16:13
Default
  #3
New Member
 
Join Date: Dec 2009
Posts: 3
Rep Power: 7
acro is on a distinguished road
Quote:
Originally Posted by Attesz View Post
Hi,

I think it will not working. You have do define the fluid as a rotating domain, to set to the flow tangencial velocity component. But why do you want to do your simulation this way? Wit rotating domain option, you can get very accurate results, with transient simulation you can set "Transient Rotor Stator" Frame Change model, which "rotates" the domain...

Attesz
Thanks for your reply.

What you suggested is: set the fluid as a rotating domain. How about the solid domain? stationary or rotating? Do I need to make some settings to the interface?

Now that CFX can set a solid as a rotating domain, I suppose this option is somehow useful. But if I set solid as rotating domain and fluid as stationary domain, it turned out that the solid rotation has no effect on the fluid flow. I guess I might miss some settings?
acro is offline   Reply With Quote

Old   January 7, 2010, 17:53
Default
  #4
Senior Member
 
Join Date: Apr 2009
Posts: 513
Rep Power: 12
stumpy is on a distinguished road
Rotating solid domains essentially add a rotational advection term to the energy equation in the solid domain, so they are only needed when you need to account for the advection of energy due to the rotation of the solid domain (e.g. a brake disk). In your case just use a rotating fluid domain and a stationary solid domain.
liuzexiang likes this.
stumpy is offline   Reply With Quote

Old   January 7, 2010, 17:57
Default
  #5
Senior Member
 
Attesz's Avatar
 
Attesz
Join Date: Mar 2009
Posts: 355
Rep Power: 8
Attesz is an unknown quantity at this point
The solid domain is useful, when you want to take into account the heat transfer for example. Of course, you have to make it rotating. But this rotation will not rotate the flow, you have to define it separately. Otherwise, in first step, you should simulate only the flow field. Taking into account of the solid body is a refinement. The walls of the rotating body will be set rotating. If there are standing walls in the rotating body, you have to set them "Counter Rotating Walls". But I think, there is a good tutorial about it in CFX help!

Good luck,
Attesz
Attesz is offline   Reply With Quote

Old   January 7, 2010, 18:49
Default
  #6
New Member
 
Join Date: Dec 2009
Posts: 3
Rep Power: 7
acro is on a distinguished road
Thank Attesz and stumpy. I asked questions in other forums, but never got quick answers like here. I appreciate your kind help very much.

Back to my question.

My goal is to simulate a solid impeller pushing liquid. But what you suggested is to make the liquid rotating by itself. Sounds like different from the original problem. Can this kind of simulation give me accurate flow pattern just like the stationary liquid is pushed by a rotating impeller?


By the way, I do need to do conjugate heat transfer. The impeller (actually it's not a real impeller, just some solid bodies with irregular shape) generates heat.
acro is offline   Reply With Quote

Old   January 7, 2010, 18:57
Default
  #7
Senior Member
 
Attesz's Avatar
 
Attesz
Join Date: Mar 2009
Posts: 355
Rep Power: 8
Attesz is an unknown quantity at this point
This kind of simulation is the general method for modelling rotating things. I"ve never heard, and I've got absolutely no idea how to do that, what do you want!
If the solid body has effect to the flow, then model it, but note, that you need more cells.

Otherwise, I'm simulating now an RC quad rotor helicopter's propeller. We have measures for the trust, and the difference between CFD and measure is very small. We made the simulation before, to check the goodness of the propeller blades, and after that we measured them. Without solids. But by using rotating fluid domain, like we said.

Regards,
Attesz
Attesz is offline   Reply With Quote

Old   July 8, 2013, 00:43
Default how could i merge two domains in one simulation?
  #8
New Member
 
omid kazemi
Join Date: Jun 2013
Posts: 1
Rep Power: 0
Omid is on a distinguished road
Hi buddies
I want to simulate a simple physic environment, in which one's outlet would be another's inlet, the first's outlet flow will receive to second domain after about 20 seconds, how could I define this correlation?
Regards,
Omid.
Omid is offline   Reply With Quote

Old   July 8, 2013, 08:11
Default
  #9
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,807
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Periodic boundaries can do it - but not with a time delay.
ghorrocks 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
Specify fluid in domain with CFX pre pierre CFX 2 August 10, 2006 04:48
How to apply negtive pressure to outlet bioman66 CFX 5 June 3, 2006 01:40
porous rotating solid domain kiran choudar FLUENT 0 March 4, 2006 07:19
heat transfer in solid and fluid domain Rafael CFX 1 October 5, 2005 18:29
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 16:55


All times are GMT -4. The time now is 04:41.