Measured Passage Velocities in a Radial Impeller With Shrouded and Unshrouded Configurations

The velocity field was measured in a rotating passage of a radial impeller with backward curved blades. Two versions were tested, one with an attached rotating shroud and the other with clearance between the blades and a stationary shroud surface. The distribution of velocity in the passage direction was similar in the two versions, but the pattern of cross-passage velocity in the unshrouded impeller configuration was altered strongly by the tip leakage flow entering the passage.