I am using a TVD scheme and some reduced chemical models to simulate the detonation propagating into geometries with sudden expansion. I noticed that the simulations often predict more successful transmission than the lab predictions. Would someone help me to explain this over prediction? Any suggestions would be helpful since I do not have much experience in reacting flow simulations.

Thanks.

Junhui

Hi Junhui, There are some potential cases of flame propagating overprediction - 1. - Real detonation is not fully adiabatic. Some heat is emissed by radiation 2. - Front of combustion may be retarded relative to heat rise front or shock wave. No chemical reaction is instantaneous 3. Real combustion mechanism is complex - there are set of parallel and consistent reactions, set of by-products and intermediate reactantes

All of these reasons can be less important for steady state simulations, but significant for your case.

BR, Stanislav

Thanks for your suggestions of the possible problem. Would you mind suggesting some ways to fix this kind of problem?

Junhui

Hi,

Try use multireaction (or 2-reaction) chemistry model with finite-rate kinetics model. Try to set simple radiation.

Stas

Stas,

Thanks for your suggestions. I did use multireaction chemistry models with finite-rate kinetics models. I tried different reduced models and the results are the same. I am not sure of the radiation effect. Beisdes, I am using a NASA combustion code, which does not include the radiation effect.

Thanks.

Junhui