Oxy-Fuel combustion dasac failure

Pat84 · October 11, 2011, 13:16

Hello,

I´m trying to simulate a Oxy-Fuel combustion with fluent, but when I try to ignite the mixture I get a lot of failures: "dasac failure at Temperature = XXXX.XXX K: Continuing... ", where XXX.XX represents the respective temperature.

I´m using a pressure based, coupled solver and the EDC combustion model. I have changed the turbulence model a few times, changed to laminar ED with stiff chemistry solver and changed to the pressure based solver, but it´s always the same: dasac failure.

Increasing and decreasing the isat table size and changing to direct integration is meaningless..

I´m using the extended Johnson & Lindstedt reaction mechanism by Frassoldati (the mechanism is attached).
I ignite the mixture with 2000-2500K.

If someone has experience with this problem, or an idea about fixing it, helping me would be very nice.

Best regards,
Patrick

Pat84 · October 12, 2011, 17:01

No idea? Does someone know other (under 10-15 species) mechanisms for simulating oxy-fuel combustion?

tjushang · September 21, 2014, 22:50

Hi Pat84, have you figured out your problem? I encountered this dasac failure recently and I tried several ways but nothing works.

atelcikti1 · November 15, 2018, 04:42

Increasing the ISAT error tolerance (up to 1e-2) may help but be aware of accuracy of your result.

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October 12, 2011, 17:01		#2
Pat84 Member Patrick Wollny Join Date: Apr 2010 Posts: 58 Rep Power: 16	No idea? Does someone know other (under 10-15 species) mechanisms for simulating oxy-fuel combustion?

September 21, 2014, 22:50		#3
tjushang New Member Yibao Shang Join Date: Jun 2014 Location: China Posts: 15 Rep Power: 12	Hi Pat84, have you figured out your problem? I encountered this dasac failure recently and I tried several ways but nothing works.

November 15, 2018, 04:42		#4
atelcikti1 Member Join Date: Mar 2017 Posts: 61 Rep Power: 9	Increasing the ISAT error tolerance (up to 1e-2) may help but be aware of accuracy of your result.