Learning Forum

[DaN]

Hello everyone,

I simulate gas-phase-reactions in a flow field within a tube using Fluent, DPM (with UDF for absorption) and chemkin import.

The simulation is apparently on its way to convergence, but during some iterations (every second or third) some lines (20) with this message are written:

dasac failure at Temperature = 335.62 K: Continuing...

Those iterations take much more time and the printed temperatures is always lower then 500 K though the maximum temperature within the field is 1100 K.

How can I indefinite the cause of this? I guess it is about some insufficient thermodynamic properties.

Thank you for your help.

[Rahul Kumar]

Hello,
There could be multiple reasons :
One of the reason behind this error could be incorrect mechanism. Please review the reaction mechanism you are using.
The error suggests that integration calculation for obtaining species has failed. You could increase the ISAT error tolerance temporarily and when you no longer see this message, you can revert it back to the original value.
I hope this helps!

[llccss]

Hi, I encounter the same problem. Did you solve this problem? Could you please give me some guidence?

[Shamkhal Mammadov]

Hi, did you guys find the solution for this? I am getting the same error:

 

here are my settings:

[Rob]

Have you tried increasing the tolerance as RK suggested?