Compressor shroud with swept grooves

A compressor for an aircraft engine, comprising:

• a rotor having a plurality of blades mounted for rotation about a central axis, the plurality of blades having blade tips extending between leading and trailing edges;
• and
• a shroud surrounding the rotor and having an inner surface surrounding the blade tips, a plurality of grooves defined in said inner surface of the shroud adjacent said blade tips, the plurality of grooves extending circumferentially about the shroud and extending radially from groove inlet openings defined in the inner surface to closed end surfaces of the plurality of grooves, the plurality of grooves having sidewalls extending circumferentially about the central axis, the plurality of grooves being axially spaced-apart from each other, the leading edge of the plurality of blades axially disposed between an upstream end of the groove inlet opening of the most upstream one of the plurality of grooves and a downstream end of the groove inlet opening of the most upstream one of the plurality of grooves, the plurality of grooves inclined in a fore-aft direction relative to the central axis to define a swept angle from the inner surface such that a center of the groove inlet openings is axially offset of a center of a closed-end surface of each of the plurality of grooves, the plurality of grooves angled in a circumferential direction relative to an axis normal to the inner surface such that the center of each of the groove inlet openings is circumferentially offset of the center of the closed-end surface of each of the plurality of grooves, wherein the plurality of grooves have circumferential interruptions defined by a plurality of baffles such that the plurality of grooves extend non-continuously around a shroud circumference.

A shroud treatment embedded in an inner surface of a compressor shroud surrounding a plurality of rotor blades of an aircraft engine having a central axis about which the plurality of rotor blades rotate, comprising:

• a plurality of grooves defined in the inner surface of the compressor shroud adjacent blade tips of the plurality of rotor blades, the plurality of grooves extending circumferentially about the shroud and extending radially from groove inlet openings defined in the inner surface to closed end surfaces of the plurality of grooves, the plurality of grooves having sidewalls extending circumferentially about the central axis, the plurality of grooves being axially spaced-apart from each other, the groove inlet opening of the most upstream one of the plurality of grooves having an upstream end disposed upstream of the leading edges of the plurality of rotor blades and a downstream end disposed downstream of the leading edges of the plurality of rotor blades, the plurality of grooves spanning an overall axial distance corresponding to 30% or more of a chord length of the plurality of rotor blades, wherein the plurality of grooves have circumferential interruptions defined by a plurality of baffles such that the plurality of grooves extend non-continuously around a circumference of the compressor shroud;
• wherein each of the plurality of grooves is inclined in a fore-aft direction relative to the central axis to define a swept angle from the inner surface such that a center of the groove inlet openings is axially offset of a center of a closed-end surface of each of the plurality of grooves, and each of the plurality of grooves is angled in a circumferential direction relative to a plane normal to the inner surface of the compressor shroud such that the upstream end of each of the plurality of groove inlet openings is circumferentially offset of the downstream end of each of the plurality of groove inlet openings relative to the central axis.