Extinction criteria in diffusion_flame_extinction.py

[d-e-t]

The extinction criteria in the current Cantera 2.5 version of diffusion_flame_extinction.py only works if temperature_limit_extinction is set equal to the higher gas inlet temperature. In the current version both the oxidizer inlet and extinction temperature are set to 500 K. The code would be improved if the extinction limit were defined based on the inlet temperatures, such as changing line 67 to:

temperature_limit_extinction = max(f.oxidizer_inlet.T, f.fuel_inlet.T)

Alternatively, temperature_limit_extinction could be set using a dT above the max inlet temperature, and then extinction checked for with np.max(f.T) < temperature_limit_extinction, as in the <= 2.4 version of the example. (Instead of the current np.isclose() in line 144)

The stopping criteria for the example was changed with commit f13bbb9c, and this issue is discussed in the User Group here.