Combustion problems: solver divergence occurs when turning on high temperature patch

nishant · February 2, 2015, 12:01

hello,
Im currently working on unsteady combustion of methane/air mixture with equivalence ratio of 0.75. I used the fluent guide to implement the two step process. my cold flow solution has converged and all ready. But as soon as i patch a region with high temperature and small concentration of products, I get divergence in solver and also a floating point exception. Really need help.
Thank you in advance

Andrea1984 · February 4, 2015, 08:58

Hi,

have you tried to reduce your URFs? Usually i set the one for density at about 0.3

Andrea

ssixr · February 8, 2015, 05:20

Quote:

Originally Posted by nishant

hello,
Im currently working on unsteady combustion of methane/air mixture with equivalence ratio of 0.75. I used the fluent guide to implement the two step process. my cold flow solution has converged and all ready. But as soon as i patch a region with high temperature and small concentration of products, I get divergence in solver and also a floating point exception. Really need help.
Thank you in advance

Hi,
For how much temperature, you are patching?

Sudhir

February 2, 2015, 12:01	Combustion problems: solver divergence occurs when turning on high temperature patch	#1
nishant New Member Nishant Join Date: Apr 2014 Posts: 1 Rep Power: 0	hello, Im currently working on unsteady combustion of methane/air mixture with equivalence ratio of 0.75. I used the fluent guide to implement the two step process. my cold flow solution has converged and all ready. But as soon as i patch a region with high temperature and small concentration of products, I get divergence in solver and also a floating point exception. Really need help. Thank you in advance

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February 4, 2015, 08:58		#2
Andrea1984 Senior Member Andrea Join Date: Feb 2012 Location: Leeds, UK Posts: 179 Rep Power: 16	Hi, have you tried to reduce your URFs? Usually i set the one for density at about 0.3 Andrea