Counterflow non-premixed Matlab module

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Hello,

      I was wondering how to compute the extinction strain rate in the counterflow non-premixed flame problem (Matlab module). I am trying to compute the extinction strain rates for propane-air flames at different pressures. What I was doing until now was increasing the mass flux hence the strain rates of fuel and air and then measuring the corresponding flame temperature and the strain rate at which the flame temperature would be more or less equal to the initial or the ambient temperature would be my extinction strain rate.
     But when I increased the resolution on the initial grid and also changed the refine criteria I am getting a flame even at the strain rate when earlier it would not give me a flame. How is this possible?
Is there a better way to find the extinction strain rate? (I couldn't find any 
function that would do that)
Is there a bug in cantera that needs to be fixed?

Any help would be appreciated!

Thanks a lot!

Parth S

Original issue reported on code.google.com by shah13pa...@gmail.com on 29 Oct 2012 at 9:31

[GoogleCodeExporter]

There is no built-in function for calculating the extinction strain rate in 
Cantera. I think gradually increasing the mass flux until you blow out the 
flame is the correct approach for finding the extinction strain rate using 
Cantera's flame solver. What you should do, though, is use the refined solution 
from the lower strain rate case as the initial condition for the next step up 
in mass flow rate. As you approach the extinction strain rate, the initial 
condition of a stable flame at a lower strain rate is more likely to converge 
to the non-extinguished solution (if it exists) than the guessed profiles on a 
coarse initial grid. Several of the 1D flame examples show how to restart a 
simulation from an existing set of profiles, so that should give you a good 
starting point.

(Copied from my response to the Cantera User's Group, which I think is a better 
place to address this question)

Original comment by yarmond on 30 Oct 2012 at 4:14

• Changed state: Invalid