Radial Fluid Flow from Rotating Impeller

[bravo03]

I am working with a rotating region surrounding a radial style impeller in a large atmospheric tank.  Does anyone know of a reasonable method to capture the radial flow (in gpm, in^3/sec, etc)?

Things I have tried:

-Using a cylindrical resistive type element with open ration set to 100%. A few different scenarios were setup but some of the results did not appear realistic. 

-Summary planes were an option but when I tried to make a cylindrical surface the plane (okay, it's not a plane), it wasn't an option. 

-Creating a polygon (12 sides) to fit just outside the rotating region (similar fluid to the tank) and then utilizing the Bulk properties to calculate flow through each of the 12 planes for a combined flow.  Not too bad until you have 10 designs, several iterations, and then having to manually select each plane and record values manually in a spreadsheet to summarize the data.

-Trying to use 12 summary planes on the polygon but it captures all fluid on the entire plane through the tank.

-Created discs the size of the impeller to capture the in flow on the upper and lower sides of the impeller.  However, some of the geometry prevents the disc from being close enough to prevent other entrained fluid from entering and not being captured.

Looking for a proven method to reasonably capture radial flow.  I am working with local support from our reseller, but this is as far as we have gotten. 

Thanks.