Abstract: The centrifugal compressor described includes an impeller shroud which encloses the impeller and has a curved shroud surface that extends between an inducer portion and an exducer portion. The compressor includes one or more circumferential grooves in the shroud body within the exducer portion. Each groove has opposed wall segments spaced apart therefrom. The wall segments are inclined at a nonzero groove angle relative to a normal of the shroud surface in a direction opposite the fluid flow path along the shroud surface.

Abstract: A compressor for a gas turbine engine having a bleed air recirculation system includes a plurality of bleed holes extending through the shroud at a first axial location thereon substantially adjacent the blade tips. The bleed holes have a closed outer perimeter along their complete length. An annular bleed cavity surrounds the shroud and is in communication with outlet openings of the bleed holes. The bleed holes provide communication between said main gas flow passage and the bleed cavity. The bleed cavity includes exit passages having outlets disposed in said shroud at a second axial location which is upstream of both the first axial location and the leading edge of the blades of the rotor. Bleed air is passively bled from the main gas flow passage via the bleed holes, recirculated through the bleed cavity and re-injected back into the main gas flow passage at the second axial location.

Abstract: A rotor for a gas turbine engine includes a plurality of radially extending blades, each having a remote blade tip defining an outer tip surface, and a leading edge defined between opposed pressure and suction side airfoil surfaces. A shroud circumferentially surrounds the rotor, and a radial distance between an inner surface of the shroud and the outer tip surface of the blades defines a radial tip clearance gap therebetween. The tip of each of the blades has a pressure side edge formed at the intersection between the outer tip surface and the pressure side airfoil surface, and a suction side edge formed at the intersection between the outer tip surface and the pressure side airfoil surface. The suction side edge has a larger radius of curvature than the pressure side edge, thereby reducing the amount of tip leakage flow through the radial tip clearance gap.