Flow Pressure Results Reversed???

I have created a centrifugal water/air separation vessel using Flow.  The primary flow media is water and the air was simulated by using a particle injection of low density polypropylene particles if 0.125 inch diameter.  The trajectories of the water and the particles (air) are exactly as desired.

However, when I do the pressure plot, the outlet pressure is greater than the inlet pressure. Has Flow just reversed my results??

SolidworksFlow Simulation