Multiphase and MHD
 

Dear CFD users,
can anyone tell me if the free surface model (VOF) is compatible with magnetohydro dynamics module (MHD) in CFX?
Has anyone of you experiences with MHD+VOF?

thanks :)

I cannot see why it would not work. Have you checked the CFX product physics compatibility chart? You can get that from the ANSYS homepage.

Hi Glenn,
the problem is that I simulate a very easy case (a cube!) in which 2 fluids are in a domain (separated because of their density difference) and electricity pass through them. In case that I start the simulation with both VOF and MHD active, I get directly in the solver setting the famous error message. The problem can be solved if I use only one fluid and deactivate VOF.
I think the program can not calculate the electromagnetic field with volume fraction terminology. What do you think? Have you ever heard of a simulation with both models running at the same time?

thanks

in Ansys website I could not find anything stating if both models can be used at the same time. They only say that these models are available in CFX!

"Famous error message" is not very useful. What error message?

I think you can not use it, As far as I read about it.
The point is that those magnetic field will affect the motion withing domain.
Sometimes those changes effects are taking into consideration through the source terms, I have red about multiphase model and I have not read about those (MHD) terms on the source terms for multiphase models.

this is the error message:

+--------------------------------------------------------------------+
| Job Information |
+--------------------------------------------------------------------+

Run mode: serial run

Host computer: EMEIS261 (PID:4840)
Job started: Tue Oct 11 13:37:20 2011

Details of error:-
----------------
Error detected by routine PSHDIR
CDRNAM = ../../BPOT
CRESLT = NONE

Current Directory : /FLOW/ALGORITHM/ZN1/SYSTEM/EQUATIONS/BPOT_FL2/TERM1

+--------------------------------------------------------------------+
| ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Stopped in routine MEMERR |
| |
| |
| |
| |
| |
+--------------------------------------------------------------------+

+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| The ANSYS CFX solver exited with return code 1. No results file |
| has been created. |
+--------------------------------------------------------------------+

End of solution stage.

This run of the ANSYS CFX Solver has finished.

Hello aria, apparently the ansys documentation points that those subroutines (PSHDI, CDRNAM) are folder creation and most likely memory allocation (The MEMERR routine does sound like that) ; do try changing the solver parameters for allocating up to 1.4-1.5 memory. It does make sense it should happen when you have 2 fluids since you're adding complexity to the problem. See also if there are any changes when you change the mesh.

HI,I meet the same question as yours for a long time. But as i really read a paper about the multiphase with electric. i can not find the error in my program.