An impeller includes a shroud including an inlet, a hub facing the shroud, and a plurality of blades disposed between the hub and the shroud and arranged circumferential direction along a circumference of the inlet. Each of the plurality of blades has a slot which is positioned adjacent to the inlet.

A propeller fan includes: a hub having a side surface about a center axis; and a plurality of blades provided on the side surface of the hub. Each blade includes an inner peripheral portion positioned closer to a base portion of the each blade connected to the hub, and an outer peripheral portion positioned closer to an outer edge of the each blade. A ratio r/R between a radius r as a distance from the center axis to a boundary between the inner peripheral portion and the outer peripheral portion and a radius R as a distance from the center axis to the outer edge of each blade is equal to or lower than 0.4. A relational expression of V1<V2×1.3 is satisfied, where an air velocity at the outer peripheral portion is V1 and an air velocity at the inner peripheral portion is V2.

A centrifugal compressor includes: an impeller; a compressor inlet tube configured to guide air to the impeller; a scroll flow passage disposed on a radially outer side of the impeller; a bypass flow passage branching from the scroll flow passage via a branch port, the bypass flow passage connecting to the compressor inlet tube not via the impeller; and a bypass valve capable of opening and closing a valve port disposed in the bypass flow passage. The branch port has a non-circular shape when viewed along a normal N1 of the branch port passing through a center of the branch port.

A blade includes: an airfoil portion having a pressure surface and a suction surface each of which extends between a base end and a tip end along a blade height direction between a leading edge and a trailing edge; and an internal passage passing through an inside of the airfoil portion, the internal passage having a first opening end opening to one of the pressure surface or the suction surface and a second opening end which is positioned closer to the tip end than the first opening end in the blade height direction and opening to a surface of the airfoil portion. When L is a length from the base end to the tip end in the blade height direction, a distance from the base end to the first opening end in the blade height direction is not less than zero and not greater than 0.3 L.

A stator structure and a gas turbine having the same are provided. The stator structure includes a plurality of rows of stators arranged on an inner peripheral surface of a casing, the stators being arranged alternately with a plurality of rows of blades arranged on an outer peripheral surface of a rotor, wherein each of the stators includes a vane including a first end and a second end, the first end of the vane being coupled to the inner peripheral surface of the casing by a first rotating member and a diaphragm coupled to the second end of the vane by a second rotating member. A first gap is formed between the first end of the vane and the inner peripheral surface of the casing, and a second gap is formed between the second end of the vane and the diaphragm. The vane may be provided with a slot part connected to the first and second ends of the vane to bypass a part of working fluid to the first and second gaps.

A diffuser for a compressor of a gas turbine engine is disclosed. The diffuser has a plurality of diffuser pipes circumferentially distributed about an axis of the compressor, each of the plurality of diffuser pipes extending from an inlet to an outlet and having a bend section between the inlet and the outlet, a low pressure side and an opposite high pressure side. A recirculation conduit defines a recirculation path from a first flow region to a second flow region in one or more of the plurality of the diffuser pipes, the first flow region having a greater static pressure than that of the second region, the recirculation conduit having a conduit inlet and a conduit outlet, at least the conduit outlet located within the low pressure side of one of the plurality of the diffuser pipes.

A centrifugal compressor includes a rotary shaft; a hollow casing; a first-stage inlet guide vane; a first-stage impeller; a diffuser; a return flow channel; return vanes; a second-stage inlet guide vane; and a second-stage impeller. The return vanes are arranged at predetermined intervals in a circumferential direction of the rotary shaft and a vane angle of each return vane is changed in a region from a leading edge, at which the fluid is introduced, to a predetermined position and the vane angle is maintained constant in a region from the predetermined position to a trailing edge, at which the fluid is discharged, in terms of meridian plane distance in a direction from the leading edge to the trailing edge.

An inner peripheral blade projects from the positive pressure surface of the blade surface part toward a positive pressure side, includes a front edge in a rotation direction of the inner peripheral blade that is formed in a curved shape to be separated from a reference line toward the front edge side in the rotation direction of the blade, the reference line connecting a lower end positioned on the positive pressure surface at a base end of the inner peripheral blade connected to the side surface of the hub with an outer edge of the inner peripheral blade that is extended from the side surface toward an outer edge side of the blade and positioned on the positive pressure surface, and satisfies H/L≥0.1, where L is a length of the reference line and H is a maximum value of a distance between the reference line and the front edge of the inner peripheral blade.

A centrifugal compressor for an aircraft engine is disclosed, having an impeller mounted for rotation about an axis. The impeller has impeller blades extending from an inducer end to an exducer end. A shroud extends over the impeller blades. A main flow passage is defined between the shroud and the impeller, a cavity fluidly communicates with the main flow passage via at least one extraction port and at least one reinjection port. The reinjection port is fluidly connected to the main flow passage upstream of the extraction port relative to a flow direction through the main flow passage. The reinjection port is disposed upstream of the exducer end of the impeller blade, in an exducer portion of the shroud.

A centrifugal compressor for an aircraft engine is disclosed, having an impeller mounted for rotation about an axis. The impeller has impeller blades extending from an inducer end to an exducer end. A shroud extends over the impeller blades. A main flow passage is defined between the shroud and the impeller, a cavity fluidly communicates with the main flow passage via at least one extraction port and at least one reinjection port. The reinjection port is fluidly connected to the main flow passage upstream of the extraction port relative to a flow direction through the main flow passage. The reinjection port is disposed upstream of the exducer end of the impeller blade, in an exducer portion of the shroud.