Comparison between the full chemistry and global reaction models for tulipflame simulation

Laminar hydrogen-air flames propagating in a closed chamber are simulated b y using a full chemistry and a global reaction model with various wall cond itions. The results show that both models can predict the tulip flame forma tion. However, compared to the global reaction model, the full chemistry mo del shows more accurate flame structure such as the formation of unburnt ga s pocket and cellular flame at the end stage of its propagation. The full c hemistry model also shows that the "squish flow" in the unburnt region betw een the flame and the side wall persists during the period of tulip flame f ormation. The flame shape does not strongly depend on the wall conditions. On the other hand, in the global reaction model, the flame characteristics sensitively depend on the magnification of the viscosity coefficient, altho ugh the burning velocity in the model must be independent of the viscosity.