[Weiqiang Liu]

Hello, all,

I am doing a catalytic micro-combustion with both gas phase and surface mechanism. The cell number is 40000. The total number of reactions is 360.

I am wondering how many iterations I need to calculate to get converged results. Right now, I am calculating with 50000 iterations.

Can anybody tell me according to your experience?

Thanks

Weiqiang

[Gert-Jan]

- What software?
- how do you judge whether if you reach convergence or not?

- is it transient?


In other words, impossible to say with the info you provide. You need to be more specific.

[Weiqiang Liu]

Originally Posted by Gert-Jan

- What software?
- how do you judge whether if you reach convergence or not?

- is it transient?


In other words, impossible to say with the info you provide. You need to be more specific.

hello，

I am using fluent 17.0. I judge the convergence by residual value. In specific, energy residual is below 1e-6, while others are below 1e-3.

My case is steady state.

Thanks

[Gert-Jan]

I would ask this question in the fluent forum.
Nevertherless, never only judge on residuals:
1) Monitor imbalances such that "in" equals "out". Also monitor maximum and mimimum values. All have to be flatliners.
2) Even better, create monitor points where you monitor concentrations. These have to be flatliners too.

Regarding calculation times, depends on your computer, parallelization, number of reactions, initial guess, etc. Chemistry is mostly very stiff. So, it can last over 1000 hours.