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-   -   please help with combustion divergence!! (http://www.cfd-online.com/Forums/fluent/113869-please-help-combustion-divergence.html)

HeKhalil February 28, 2013 06:50

please help with combustion divergence!!
 
:confused: Dear guys;

I am simulating a steady flame of lean methane/air mixture in a swirl stabilized dump combustor. Because of similarity, i took only quarter section of combustor with periodic boundary condition in the azimuthal direction. my equivalence ratio is 0.65. the problem is that when i used finite rate/eddy dissipation model i have no ignition despite i tried both patching and initialization. i tried eddy dissipation model alone and i have divergence error in AMD solver and temperature exceeds 5000. i tried patching the entire domain with 2500 k and i have the same errors. i tried patching with products in the entire domain and i got same errors. i tried without patching at all and i got same errors!!!

of course this all were done either with initializing the solution or starting with steady cold flow solution.

kindly advice what to do, shall i check the grid or what, knowing that i use pressure based solver, second order schemes and courant number of 1.

diamondx February 28, 2013 14:37

how is the convergence doing in cold flow ??

HeKhalil March 1, 2013 07:56

It is perfect. I have convergence in cold flow to below 1e-4 in continuity and below 1e-4 in other equations


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