Multiphase and MHD

aria · October 18, 2011, 11:35

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

ghorrocks · October 18, 2011, 17:58

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.

aria · October 19, 2011, 15:48

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

aria · October 19, 2011, 15:51

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!

ghorrocks · October 19, 2011, 18:44

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

juliom · October 20, 2011, 09:58

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.

aria · October 21, 2011, 10:53

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.

mauricio · October 22, 2011, 03:10

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.

liuzexiang · October 30, 2012, 10:23

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.

October 18, 2011, 11:35	Multiphase and MHD	#1
aria New Member Join Date: Sep 2011 Posts: 5 Rep Power: 15	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

October 22, 2011, 03:10		#8
mauricio Member Mauricio Labarca Join Date: Aug 2009 Posts: 35 Rep Power: 17	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. liuzexiang likes this.

October 18, 2011, 17:58		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	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.

October 19, 2011, 15:48		#3
aria New Member Join Date: Sep 2011 Posts: 5 Rep Power: 15	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

October 19, 2011, 15:51		#4
aria New Member Join Date: Sep 2011 Posts: 5 Rep Power: 15	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!

October 19, 2011, 18:44		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	"Famous error message" is not very useful. What error message?

October 20, 2011, 09:58		#6
juliom Senior Member Julio Mendez Join Date: Apr 2009 Location: Fairburn, GA. USA Posts: 290 Rep Power: 18	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.

October 21, 2011, 10:53		#7
aria New Member Join Date: Sep 2011 Posts: 5 Rep Power: 15	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.

October 30, 2012, 10:23		#9
liuzexiang Member liuzexiang Join Date: Oct 2012 Location: China Posts: 69 Rep Power: 14	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.