Thanks Rob! So for the lower flow time the simulation advanced another second realtime using a time-step an order of magnitude smaller than my original set. The simulation set with the greater flowrate is still running. Based upon some of my readings I targeted a Courant number of 0.1 and figured that I have two characteristic velocities for each simulation set. The first is the impeller tip velocity (which is about 2 m/s) and the second is the bubble velocity entering the simulation through the gas inlets (either 0.1 or 0.01 m/s). I know that these components will combine in some form to provide the bubble velocity. The smallest grid size region is near the impeller and I've set that to 7mm. So based upon these parameters I determined my time step could be from 0.0004-0.07 s. I'm going to decrease my time step and see what happens.

I also recieved this message:

WARNING: 0.0140% of the total discrete phase mass was not tracked for the expected residence time:0.00125 s less on a mass-weighted average (which is 0.2040% of their total age or 62.5617% of the last time step).You may be able to reduce this discrepancy by increasing the maximum number of time steps used to compute a single particle trajectory.