CFD Online Discussion Forums - Throttle Intake Analysis

Dear All,

I am currently working on a small throttle air intake analysis using Autodesk Sim CFD. I have elected to use the discharge coefficient $C_D = Q/\sqrt{2\cdot \frac{\Delta p}{\rho}}\cdot A$ to measure any change in performance.

I was hoping someone could provide guidance on the correct boundary conditions to apply to achieve a desired $\Delta p$ ? As of now I have created a volume surrounding the air intake to which I apply an absolute pressure of 101325Pa (1atm). I then apply an absolute pressure of 92114Pa to the outlet of the intake (looking for a pressure ratio of 1.1 initially). Sim CFD counts these as 2 outlets instead of 1 outlet, is this set up correct?

Many thanks in advance.