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

Problem in cyclone simulation

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 10, 2002, 12:18
Default Problem in cyclone simulation
  #1
JiChun
Guest
 
Posts: n/a
Hello, everyone,

Right now I am solving a cyclone problem and getting some troubles.

1) It is very difficult to get converged results. Even if I get a converged result, I still doubt if it is correct because the result shows that there is no reverse flow occuring at one of the outlets.

2) According to the Fluent manual, I should use RSM turbulent model to simulate this case(for strong swirling flow), but this model fails to give me a converged result. While RNG and realized model give me a converged result.

3) Some funny things happened. Sometimes I got a converged result with reverse flow at one of the outlets and sometimes not.(I used the same boundary conditions)

Bye the way, my current computational grids are tetrhedral elements( It is hard to use hex elements to generate the meshes for this case). Could this a problem?

Your advices and suggestions are highly appreciated.

  Reply With Quote

Old   May 12, 2002, 21:37
Default Re: Problem in cyclone simulation
  #2
Jin-Wook LEE
Guest
 
Posts: n/a
1. Convergence : It is very natural that It is very difficult to get converged results for cyclone simulation. You may have couple of trials.

2. Turbulence model : It is very difficult to get 'Rankine vortex', which is common phenomenon of cyclone, by RNG model. So, many people recommend RSM.

3. Mesh : Frankly speaking, I do not exactly know why hexa is recommended. They say 'PRESTO' is prefered for cyclone simulation. Then hexa should be used. Anyway, it was difficult. But it is possible to generate hexa elements for cyclone modeling.

Sincerely, Jinwook

  Reply With Quote

Old   May 14, 2002, 16:33
Default Re: Problem in cyclone simulation
  #3
l.ma
Guest
 
Posts: n/a
Hi,

Usually this problem is caused by using bounday conditions not correct represent physical model. Please check it carefully.

  Reply With Quote

Old   May 15, 2002, 15:48
Default Re: Problem in cyclone simulation
  #4
JiChun
Guest
 
Posts: n/a
Thank you for both of you for the response.

So could you give me some advices how to set the correct boundary conditions for this case?

Thanks a lot!
  Reply With Quote

Old   May 18, 2002, 08:45
Default Re: Problem in cyclone simulation
  #5
cwflying
Guest
 
Posts: n/a
how did you describe the air core boundary conditions?
  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
Problem with torque output from a turbine simulation. pa-dundas FLUENT 5 July 17, 2022 06:27
a problem of nozzle simulation xck1986 OpenFOAM 11 November 27, 2012 09:22
Problem Concerning free surface wave simulation michaels STAR-CCM+ 3 February 25, 2011 08:28
Urgent; convergence problem in MRF simulation Mansureh ANSYS 4 February 2, 2011 07:00
Star-CD transient simulation, problem of loss of mass kit STAR-CD 3 April 13, 2010 12:34


All times are GMT -4. The time now is 10:09.