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