A centrifugal compressor includes: an upstream side squeeze portion having a flow passage cross-sectional area that decreases as the upstream side squeeze portion extends closer to a compressor impeller; a partition wall facing the inner circumferential surface of the upstream side squeeze portion and arranged with a gap from the inner circumferential surface of the upstream side squeeze portion; and a protrusion protruding from at least one of the inner circumferential surface of the upstream side squeeze portion or the outer circumferential surface of the partition wall.

Am aircraft engine including an axially extending inlet wall surrounding an inlet flow path. A radial distance between the inlet wall and the inner wall adjacent the fan defines a downstream height of the inlet flow path. A plurality of vanes are circumferentially spaced around the inlet, each of the vanes extending radially inwardly from the inlet wall, a maximum radial distance between a tip of each of the vanes and the inlet wall defining a maximum height of the vane. The maximum height of the vane is at most 50% of the downstream height of the flow path. In another embodiment, the maximum height of the vane is at most 50% of the maximum fan blade span. A method of reducing a relative Mach number at fan blade tips is also discussed.

A compressor has: a rotor and a stator having vanes, a vane of the vanes having an airfoil extending from a root proximate an inner hub to a radially outer tip, the airfoil having a leading edge, a trailing edge, and a chord extending between the leading edge and the trailing edge to define a chord length, the airfoil having a pressure side surface and a suction side surface, and a fillet disposed at the leading edge of the root of the airfoil and extending between the pressure side surface and the inner hub, the fillet having a radial height being maximum at the leading edge, the radial height decreasing from the leading edge to blend smoothly into a remainder of the airfoil, the fillet extending downstream from the leading edge a chord-wise distance of less than 50% of a chord length of the airfoil on the pressure side surface.

An axial fan for an outdoor unit of an air conditioner is provided. The axial fan may include at least one blade connected to a hub. The at least one blade may include a blade inner portion, a blade outer portion provided outside of the blade inner portion in a radial direction, and a blade connector that connects the blade inner portion and the blade outer portion as a curved surface, thereby improving noise and increasing an air volume.

The compressor for a gas turbine engine includes a rotor with blades, and a shroud surrounding the rotor and having an inner surface surrounding tips of the blade. A plurality of grooves are defined in the inner surface of the shroud adjacent the blade tips, the grooves extending circumferentially about the shroud and extending radially from groove inlet openings defined in the inner surface to closed end surfaces of the grooves. The grooves are axially spaced-apart from each other and disposed axially between the leading and trailing edges of the blades. The grooves have a forwardly swept angle from the inner surface, and circumferential interruptions such that the grooves extend non-continuously around the shroud circumference.

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. Wherein each of the plurality of blades has a slot which is positioned adjacent to the inlet.

A centrifugal compressor includes an impeller configured to drive fluid along a fluid flowpath via a plurality of discrete passages. Each of the discrete passages includes a discrete passage exit. A diffuser portion is disposed circumferentially about the impeller. The diffuser portion includes a plenum connected to each exit of the discrete passages via a plurality of diffuser inlets and an equalization plenum defined adjacent to the impeller. The equalization plenum is fluidly connected to each discrete passage exit via a corresponding slot.

A ceiling fan includes: a column; a hub case which is coupled to the column and rotatable with respect to the column; and a plurality of blades disposed in the hub case, wherein each of the blades comprises: an upper blade having one end coupled to the hub case; a lower blade which has one end coupled to the hub case and is spaced apart from the upper blade; and an end tip connecting the other end of the upper blade and the other end of the lower blade.

A turbomachine includes a rotor and a stator, the stator having a plurality of profiled structures, each profiled structure being elongated in a direction of elongation in which the profiled structure has a length exposed to an airflow, and having a leading edge and/or a trailing edge, at least one of which is profiled and has, in said direction of elongation, serrations defined by a succession of peaks and troughs and having a geometric pattern transformed, over at least a part of said length exposed to the airflow, by successive scaling, via multiplicative factors, in the direction of elongation and/or transverse to the direction of elongation. The geometric pattern, as defined with reference to a radial distribution of the integral scale of the turbulence, evolves in a non-periodic manner.

A fan noise-lowering structure includes a fan frame and a connection section. The fan frame has a bottom side and a circumferential wall. The circumferential wall defines an airflow passage. Two ends of the airflow passage respectively have an inlet and an outlet. The connection section is disposed on inner side or outer side of the circumferential wall. The connection section has an internal passage. Two ends of the internal passage respectively have an inlet end and an outlet end. The outlet end is disposed on the inner side of the circumferential wall in connection with the airflow passage near the inlet. The inlet end is disposed on the bottom side in flush with the outlet. The connection section serves to guide the high-pressure air at the outlet to jet to the inlet so as to achieve multiple noise-lowering effects.