combustion mechanism

vahidzanganeh · January 1, 2013, 13:31

Hi Foamers,
I'm working on a simulation of combustion in porous media with my new solver porousReactingFoam . for global mechanis ch4 is correct but for 4 step mechanism ch4 is divergence.
error is termonal :
--> FOAM FATAL ERROR:
Too many integration steps

From function ODESolver::solve(const ODE& ode, const scalar xStart, const scalar xEnd,scalarField& yStart, const scalar eps, scalar& hEst) const
in file ODESolvers/ODESolver/ODESolver.C at line 107.

FOAM exiting

Who can help me?

adhiraj · January 2, 2013, 11:42

Hi,
this error means that the ODE solver that you are using to solve the 'chemistry' is unable to find solutions even after a large number of steps.
Can you try with:
a) a smaller time step (in controlDict)
b) a different ODE solver?

vahidzanganeh · January 2, 2013, 16:09

dear adhiraj
the time step is 10e-6
I am an energy source in the Appropriate timestep I use to simulate ignition.
after ignition the velocity in cells goes up very high(about 100 scale) and solution is divergent.
Courant number was controlled by adjusting the timestep but not divergent. and the temperature of the solution increases.
comment:
for global mechanism ch4 is correct but for 4 step mechanism ch4 is divergence For the same conditions.!!

Best Regards

January 1, 2013, 13:31	combustion mechanism	#1
vahidzanganeh Member v Join Date: Nov 2011 Posts: 33 Rep Power: 15	Hi Foamers, I'm working on a simulation of combustion in porous media with my new solver porousReactingFoam . for global mechanis ch4 is correct but for 4 step mechanism ch4 is divergence. error is termonal : --> FOAM FATAL ERROR: Too many integration steps From function ODESolver::solve(const ODE& ode, const scalar xStart, const scalar xEnd,scalarField& yStart, const scalar eps, scalar& hEst) const in file ODESolvers/ODESolver/ODESolver.C at line 107. FOAM exiting Who can help me?

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January 2, 2013, 11:42		#2
adhiraj Senior Member Adhiraj Join Date: Sep 2010 Location: Karnataka, India Posts: 187 Rep Power: 16	Hi, this error means that the ODE solver that you are using to solve the 'chemistry' is unable to find solutions even after a large number of steps. Can you try with: a) a smaller time step (in controlDict) b) a different ODE solver?

January 2, 2013, 16:09		#3
vahidzanganeh Member v Join Date: Nov 2011 Posts: 33 Rep Power: 15	dear adhiraj the time step is 10e-6 I am an energy source in the Appropriate timestep I use to simulate ignition. after ignition the velocity in cells goes up very high(about 100 scale) and solution is divergent. Courant number was controlled by adjusting the timestep but not divergent. and the temperature of the solution increases. comment: for global mechanism ch4 is correct but for 4 step mechanism ch4 is divergence For the same conditions.!! Best Regards