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Old   February 20, 2010, 22:21
Default Negative temperature
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Anjan
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Hello ,

I am working on combustion of methane , where there are 50 species and 400 reactions . for initial solution i use non premix / partially mix pdf models and after wards i use edc models . but when i import my mechanism file and thermo file and enable the edc model and start the iterations

i get this sort of error on the very first iteration .




Error: ISAT reaction rate: Temperature = -7274.0K
Error Object: ()
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Old   July 13, 2011, 09:59
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Hello,

did you solve the problem? I'v pretty much the same, so it would be very nice to know how to handle it.

Thanks in advance!!
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Old   July 13, 2011, 10:08
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Miguel Graša
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I've run into this problem while running a non-premixed turbulent combustion case...What I did was to set upper and lower limits for temperature closer to what my problem would present, in the Solution Controls tab. (In my case, I set the lower limit to 200K and the upper limit to something like 2500K, yours may differ of course). I did work in the end.
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Old   July 13, 2011, 10:48
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Thanks for your help Mike!
Unfortunately my problem seems to be a little more besetting... I set Temperature limits to 250 and 1600K but its still the same...

Primitive Error at Node 1: ISAT reaction rate: Temperature = -1248.0K

Anybody that had a similar problem and knows a solution?

much thanks in advance!!!
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Old   January 2, 2014, 22:49
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James Evon D'Souza
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Hi,

I've encountered a similar problem where a heat source leads to negative temperatures in the system which is not physically sound. I also noticed that setting the lower temperature limit to say 300K does not limit the static temperature to 300K but the total temperature. Any further insights would be welcome.
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