
[Sponsors] 
February 1, 2007, 05:43 
how to increase "Newton Pressure Iteration Limit"

#1 
Guest
Posts: n/a

I am running a big mesh simulation (nodes: 40300) with two domain interfaces. it is a gas mixture flow and particle tracking only simulation.
In the first iteration, the out file gives the information as below, ++  The Newton iteration was either slowly converging or has stalled.   The solver will continue with the variable set as it was on the   final iteration. If this situation continues you might try   increasing the number of iterations allowed for Newtons method.   This can be changed by setting one of the parameters:   Temperature : "Constitutive Relation Iteration Limit"   Pressure : "Newton Pressure Iteration Limit"   for your mixture using the definition file editor.  ++ According to this message, I am trying to increase the number of iterations for Newtons (Constitutive Relation Iteration Limit and Newton Pressure Iteration Limit) for a material. But I cannot find them in CFXPre. Then I had to search them two in CFXHELP. The HELP (Reference Guide  ANSYS CFXPre CCL Details  CCL Objects ) says as below, Using the CCL Content Documentation: This document is generated from the CFXPreRules.ccl file in the ANSYS CFX/etc/ directory. It contains a description of all the possible CCL objects and parameters. But any modifications are prohibited in CFXPreRules.ccl . Anybody are experienced in this? any suggestion on this problem? Looking forward to you reply. Thank you very much in advance. 

February 15, 2007, 15:50 
Re: how to increase "Newton Pressure Iteration Lim

#2 
Guest
Posts: n/a

If you go into you defenition file editor from post, u can add a paramether to one of your mixtures. The Newton Pressure Iteration Limit can be modified from there.


February 15, 2007, 19:30 
Re: how to increase "Newton Pressure Iteration Lim

#3 
Guest
Posts: n/a

Dear Georges,
I just cannot find how to add a parameter to my gas mixture in POST. Could you give more details. Thanks a lot. Ben 

February 16, 2007, 09:17 
Re: how to increase "Newton Pressure Iteration Lim

#4 
Guest
Posts: n/a

Sure, When you open up Post, go to "tools/edit definition file". Once you have your file open expand the library then select the gas mixture. Once you've done that, click on Edit/Add Paramather. Hope that helps.


February 18, 2007, 19:06 
Re: how to increase "Newton Pressure Iteration Lim

#5 
Guest
Posts: n/a

Dear Georges,
Thank you for your quick response. Are you using the CFX5 versions (CFX10.0 and CFX11.0)? I cannot find the library in these versions and thus cannot add parameters to gas mixture. Looking forward to your reply. Ben 

February 28, 2007, 16:59 
Re: how to increase "Newton Pressure Iteration Lim

#6 
Guest
Posts: n/a

Hey, I'm using CFX 10. Do you not have the Edit/Add Paramather Option ?


February 28, 2007, 20:08 
Re: how to increase "Newton Pressure Iteration Lim

#7 
Guest
Posts: n/a

Hi Georges,
I found it. Thanks a lot. May I have you email for future contact? 

June 15, 2009, 07:09 

#8  
New Member
zhang tw
Join Date: Jun 2009
Posts: 1
Rep Power: 0 
Quote:


February 15, 2013, 07:49 
Now in Solver

#9 
New Member
Anton Persson
Join Date: Jul 2010
Posts: 2
Rep Power: 0 
Thank you!
In CFX 14.0 this is done in CFXSolver Manager. Go to Tools > Edit CFX Solver File > Select your material > Edit > Add Parameter BR, Anton 

April 21, 2013, 01:54 
Newton Iteration slowly converged

#10 
New Member

I have been working out with the tutorial in coal combustion.
I have been receiving the following message: The Newton iteration was either slowly converging or has stalled.   The solver will continue with the variable set as it was on the   final iteration. If this situation continues you might try   increasing the number of iterations allowed for Newtons method.   This can be changed by setting one of the parameters:     Temperature : "Constitutive Relation Iteration Limit"   Pressure : "Newton Pressure Iteration Limit"     for your mixture using the definition file editor. And I edited the file too, but what is the Constitutive Relation Iteration Limit for temperature and Newton Pressure Iteration Limit for pressure or what does that mean. The next problem is the solver runs and stalls after 2530 iterations with this message in serial mode and does not run in parallel mode. I have set expert parameters for memory allocation too. What might be the problem? Help would be appreciated. 

Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Setting minimum absolute pressure limit  meteo45fr  STARCCM+  2  May 25, 2009 02:59 
Parallel runs slower with MTU=9000 than MTU=1500  Javier Larrondo  FLUENT  0  October 28, 2007 23:30 
Gas pressure question  Dan Moskal  Main CFD Forum  0  October 24, 2002 22:02 
pressure gradient term in low speed flow  Atit Koonsrisuk  Main CFD Forum  2  January 10, 2002 11:52 
Hydrostatic pressure in 2phase flow modeling (long)  DS & HB  Main CFD Forum  0  January 8, 2000 16:00 