Is there a way to transfer this post onto fluids?

My contours are below, I've set the particle diameter as 0.008m but this was because at first I thought this was the diameter of the injection outlet (since the hole I'm trying to simulate has a diameter of 8mm). Since I don't have any idea in particular what diameter I should, use is it best just to vary the diameter parametrically? I'm also using the default settings for DPM Iteration Interval (10) and Max number of steps (50000)