
[Sponsors] 
July 14, 2012, 12:00 
"Newtons method failed in Atomization Problem

#1 
Member
Ahmet
Join Date: Mar 2011
Location: Ankara/ Turkey
Posts: 37
Rep Power: 6 
I m simulating spray of heptane. Liquid heptane sprays from an injector. but after injection began, I got this error. Because of specific heat depends on temperature, I m using Nasa polynomials. If I take a specific value for specific heat, the error doesn' t happen. How can I solve this problem?
****** Notice ******   Newtons method failed to converge in 100 iterations. This   occurred while computing the following variable:     Variable Name : Temperature   Location Name : Flow Domain 1   Mesh location : VERTICES   Mesh entity :   Last 3 Changes : 6.25499E02 4.23251E02 4.36934E02   Tolerance : 1.0000E02     The Newton iteration was diverging. The solver will continue   with the variable field as it was on the final iteration. If   this situation continues you might try decreasing the Newton   iteration under relaxation factor. This can be changed by   setting one of the following parameters:     Temperature : "Constitutive Relation Under Relaxation"   Pressure : "Newton Pressure Under Relaxation"     for your mixture using the definition file editor.  ++ Last edited by a_cucen; July 14, 2012 at 13:38. 

July 15, 2012, 05:14 

#2 
Member
Ahmet
Join Date: Mar 2011
Location: Ankara/ Turkey
Posts: 37
Rep Power: 6 
I solved the problem. But now I have another problem :S It gave this failure after 10 iterations from spray began. How can I solve this problem?
Parallel run: Received message from slave  Slave partition : 4 Slave routine : get_TWFTFC Master location : End of Continuity Loop Message label : 009100015 Message follows below  : ++  ****** Notice ******   The nondimensional near wall temperature (T+) has been clipped   for calculation of Wall Heat Transfer Coefficient.     Boundary Condition : piston   T+ clip value = 1.0000E10     If this situation persists and you are using the High Speed Model,   consider enabling Mach number based blending between low speed and   high speed wall functions. You can do so by specifying a Mach   number threshold as follows:     EXPERT PARAMETERS:   highspeed wf mach threshold = 0.1 # default=0.0 (off)   END  ++ 

July 15, 2012, 08:28 

#3 
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,800
Rep Power: 85 
If you are modelling multiphase spraying with NASA polynomial fluids then you should expect a numerically unstable simulation. You need to get each bit of this model working one at a time before doing the entire simulation.


July 15, 2012, 20:04 

#4 
Member
Ahmet
Join Date: Mar 2011
Location: Ankara/ Turkey
Posts: 37
Rep Power: 6 
I have fixed this error too. But there is something I can not explain. The liquid heptane particles are vapourised meanwhile it enters the domain. It must enter the domain in liquid form and break up to small particles in normal conditions. Where do I make mistake?


April 14, 2013, 21:48 
Newtons method failed to converge in 100 iterations.

#5 
New Member
Join Date: Dec 2012
Posts: 3
Rep Power: 4 
Dear a_cucen,
I have also countered this problem"Newtons method failed to converge in 100 iterations ",and have not find a way to deal with it.Could you tell me the reasons that cause this problem.Is it a BC problem or a grid problem?And how can I solve it? Thank you very much!I hope to hear from you soon. 

April 15, 2013, 18:50 

#6 
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,800
Rep Power: 85 
The Newtons method failed to converge message means some material properties could not converge. To debug this you should simplify your problem one thing at a time to isolate what is causing it.


April 16, 2013, 21:57 

#7 
New Member
Join Date: Dec 2012
Posts: 3
Rep Power: 4 

Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Newtons method failed to converge in 100 iterations  brajh11  CFX  5  September 3, 2011 06:29 
a problem of incompressible two phases(water and gas) with VOF Method  zhangweisnoopy  Main CFD Forum  9  August 12, 2011 08:25 
Fluent 6.3.26 vs 12.1 and partition method  Anorky  FLUENT  0  April 27, 2010 10:55 
finite difference method for navierstokes problem  dallybird  Main CFD Forum  5  February 17, 2003 23:00 
use of MAC method to solve sloshing problem.  S.R.SAHI  Main CFD Forum  1  April 15, 1999 22:28 