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

Ansys 11.0 CFX - solving electric potentials and multiphase flow

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 9, 2010, 12:25
Default Ansys 11.0 CFX - solving electric potentials and multiphase flow
  #1
New Member
 
S G
Join Date: Feb 2010
Posts: 2
Rep Power: 0
cfd_multiphyiscs is on a distinguished road
Hello



I am solving a multiphase flow where one fluid is neutral and another fluid is ionized and additionally I am solvig for electric potential in the domain. I am using Electromagnetics Beta feature in Ansys 11.0




However when I activate two fluids under the "Default Domain" tab, I am unable to specify the Electric potential boundary conditions in my domain. The relevant tabs in the Ansys CFX-Pre Gui disappear. I am able to specify the electric fields for a single fluid case.




I am not sure if Electromagentics Beta version is disabled for multiphase flow. Kindly clarify if it is so or if not? Thank you.





Assuming that the electromagentics feature can be used only with single fluid, I need help on how to implement the interaction between the two fluids.
In my simulation, the neutral fluid has influence on the ionized fluid but not vice versa. Hence I have independently solved the flow scenarios for both neutral and ion flow. I now need to couple the neutral flow solution to the ion flow solver so that the solver can calculate the body force source terms due to neutral gas on ion flow.
Kindly let me know if this is possible, if so some direction on how to do it.


Thank you.
cfd_multiphyiscs is offline   Reply With Quote

Old   March 10, 2010, 07:16
Default
  #2
Senior Member
 
ckleanth's Avatar
 
George
Join Date: Mar 2009
Location: Birmingham, UK
Posts: 257
Rep Power: 9
ckleanth is on a distinguished road
the emag in cfx 11 is pretty much way in the beta region, gui for emag is not stable and the only way to make sure that you activate emag boundaries is to direly define the boundary conditions using ccl on your def file. this means you need to know exactly what you're doing.

if you manage to make it work for you another issue with cfx11 and emag is with multiphase is that the emag variables are carried by the first defined fluid (i think this is true for all variables in multiphase and then the global variables are renamed as the res file is created, however in the case of emag some variables dont) this means you will have fluid1.energy potential however this is the global energy potential in your fluid domain.

furthermore in cfx 11 lorenz forces do affect the momentum equation however joule heating was not included in the energy equation and you need to explicitly add this source term if its important for your solution.

to answer your question, yes it is possible obviously you need to define all emag properties for all phases and quite possibly need ansys support. it is easier to work with cfx 12 as its a properly supported module.
__________________
Top 4 tips
1. Knowledge is everything and Ignorance is dangerous.
2. Understand your limitations and try to eliminate them.
3. Get yerself a bike and hoon the chuffer. You will soon learn why dogs like to hang their heads out the car window.
4. Please before asking any questions on how to run simulations in CFX, go though all the tutorials
ckleanth is offline   Reply With Quote

Old   March 10, 2010, 14:43
Default
  #3
New Member
 
S G
Join Date: Feb 2010
Posts: 2
Rep Power: 0
cfd_multiphyiscs is on a distinguished road
Hello ckleanth
Thank you for the reply. As you have indicated working in CFX 12 is more suitable for this problem.

Your quick reply is appreciated
cfd_multiphyiscs 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



All times are GMT -4. The time now is 01:36.