The impeller chamber includes {HEAD ~ a variable area} wherein {TAIL ~ a first cross sectional area} is defined between the radially outer surface and the first portion, and a second cross sectional area is defined downstream from the first cross sectional area 
The impeller chamber includes { HEAD ~ a variable area } wherein { TAIL ~ a first cross sectional area } is defined between the radially outer surface and the first portion , and a second cross sectional area is defined downstream from the first cross sectional area
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH