Inducer with shrouded rotor for high speed applications

An inducer rotor having a predetermined rotational speed mountable in an inducer for pressurizing fluid traveling through the inducer, the inducer comprising a housing surrounding the rotor having an interior surface facing the outer surface of the shroud, said housing extending axially from an inlet through which fluid is received at an inlet pressure to an outlet downstream from said inlet through which fluid is discharged at an outlet pressure higher than said inlet pressure, the inducer rotor comprising:

• a hub having a central axis;
• a plurality of blades connected to the hub, each of said plurality of blades extending radially outward from a root adjacent the hub to a tip opposite the root;
• and
• a unitary, one-piece, shroud extending circumferentially between at least one pair of adjacent blades within the plurality of blades, said shroud having an inner surface facing the central axis, an outer surface opposite the inner surface and a thickness extending between said inner and outer surface, said thickness varying circumferentially around the shroud, wherein the shroud extends circumferentially between blades adjacent the blade tips.

An inducer for pressurizing a fluid comprising:

• a housing having an interior surface facing a central axis, an inlet through which fluid is received into the housing at an inlet pressure, and an outlet downstream from the inlet through which fluid is discharged from the housing at an outlet pressure higher than said inlet pressure;
• a rotor rotatably mounted in the housing, said rotor comprising a hub centered on the central axis, a plurality of blades connected to the hub, each of said plurality of blades extending radially outward from a root adjacent the hub to a tip opposite the root and axially rearward from a leading edge to a trailing edge opposite the leading edge, and a shroud extending circumferentially between each pair of adjacent blades within the plurality of blades, said shroud having an inner surface facing the central axis, an outer surface opposite the inner surface and a thickness extending between said inner surface and outer surface;
• and
• a leading seal extending from at least one of the interior surface of the housing and the outer surface of the shroud thereby forming a leading seal gap, and a trailing seal extending from at least one of the interior surface of the housing and the outer surface of the shroud thereby forming a trailing seal gap, said leading seal being closer to the leading edge of the blades than the trailing seal;
• wherein the interior surface of the housing, the outer surface of the shroud, the leading seal, and the trailing seal define an annular cavity, the cavity being pressurized for maintaining the leading seal gap and the trailing seal gap at respective substantially uniform heights during inducer operation.