air-hydrogen combustion

steven

Hello,I'm trying to visualize a hydrogen combustion process in a simple geometry (a rectangle with 2 velocity inlet BC,one for air,one for hydrogen and a pressure outlet BC).I have troubles because a "reverse flow...at pressure outlet" message appears,consequently the calculation does not converge and the combustion does not occur(I used the "species transport" model). When I remove this model and simulate a simple air flow(species off),the reverse flow problem disappear and the calculation converges. Could you please help me? thanks