please helpme: CanteraError thrown by Phase::setTemperature

[agus prasetyo nuryadi]

Hello Everyone,

please help me,

I am trying to calculate the laminar flame speed of dodecane using Cantera, While solving for the flame speed I encountered the below error:

cantera._cantera.CanteraError:
***********************************************************************
CanteraError thrown by Phase::setTemperature:
temperature must be positive
***********************************************************************

This error pops up . I have attached below the .cti file of the mechanism along with the script used for flame speed calculation. Any suggestion will be useful. 

Thank You

Agus

[Bryan Weber]

Hi,

The main thing that I note in your simulation is this section:

# Tolerance properties
tol_ss = [1.0e-5, 1.0e-9]  # [rtol atol] for steady-state problem
tol_ts = [1.0e-5, 1.0e-9]  # [rtol atol] for time stepping

f.flame.set_steady_tolerances(default=tol_ss)
f.flame.set_transient_tolerances(default=tol_ts)

f.set_refine_criteria(ratio=2.0, slope=0.05, curve=0.05, prune=0.05)
f.set_max_jac_age(10, 10)
f.set_time_step(1e-8, [10, 20, 40, 80, 100, 100, 150])
f.max_time_step_count = 500

f.solve(loglevel, refine_grid)

On the first time you solve the system, you should not set any of these properties. The solver works much better if it can find a crude solution and iterate to a fine solution. As such, I suggest you replace all of this with the following:

f.solve(loglevel, auto=True)

f.set_refine_criteria(ratio=3.0, slope=0.3, curve=0.3, prune=0.01)

f.solve(loglevel)

f.set_refine_criteria(ratio=2.0, slope=0.1, curve=0.1, prune=0.01)

From there, you can continue to refine parameters as necessary. In addition, I recommend that you do not set any of the `max_jac_age`, `time_step` or `time_step_count` properties, as the defaults for these are likely to give you the best chance at a solution.

Best,

Bryan

[agus prasetyo nuryadi]

Hi Bryan,

I see, thank you very much for your help.

Best,

Agus

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