Liquid rocket engine combustion

Steve

Hello. I am trying to analyze the combustion of ethylene-oxygen inside a small chamber (length about 7cm) and I have been using mass flow inlets for both the fuel and oxidizer injectors. My question is about how I would go about specifying a higher pressure leaving the inlets. Currently, the mass flow is correct (ends up being a total of about .1kg/s) but the pressures in the chamber end up being only about 5000Pa/.7psi above atmospheric. What I'm trying to model should have the fuel/ox at about 1.7MPa/250psi when they enter and should also be at the mass flow rates given. The mass flow inlet has a initial pressure/supersonic input but I don't think it is being used.

Any help appreciated, I can supply more details if needed. I'm using the pressure solver, axisymmetric, K-epsilon turbulence, volumetric species transport with eddy-dissipation.

Thanks, Steve