Provided is a reversible fan including: a fin configured to produce a current of air in both of a normal direction and a reverse direction; an impeller configured to be rotatable about a rotation axis; a motor configured to rotate the impeller; and a tubular frame housing the impeller and the motor, wherein the fin has a shape that allows producing louder noise upon producing the current of air in the normal direction than upon producing the current of air in the reverse direction, and protrudes inward in a radial direction from an inner peripheral surface of the frame.

A free-tipped axial fan assembly features a shroud barrel comprising an inlet, the radius of said inlet at its upstream end being greater than the radius of said inlet at its downstream end. An angle, in a plane including the fan axis, between the surface of said inlet and the direction of the fan axis varies non-monotonically with respect to a surface coordinate which increases with distance along the surface of the inlet.

A casing treatment for a compressor includes one or more cavities in a casing disposed radially outwardly of tips of the compressor rotor blades. A liner is moveable relative to the casing between a first position and a second position. The liner is shaped to add a volume to the tip clearance gap when moving from the second position toward the first position. The liner is displaceable between the first and second positions in coordination with at least the rotation of inlet guide vanes (IGVs) between IGV positions.

Provided is a vacuum pump including a turbomolecular mechanism having rotor blades and stator blades alternately arranged in multiple stages in an axial direction inside a casing having an inlet port that sucks gas from an outside and an outlet port that exhausts the sucked gas to the outside, the vacuum pump including: a plurality of annular spacers that are stacked on each other and position the stator blades in the axial direction; the casing that has a cylindrical portion arranged to surround outer peripheries of the plurality of stacked spacers and a base portion attached to a lower portion of the cylindrical portion; and an upper radial positioning portion and a lower radial positioning portion provided at two vertical positions inside the cylindrical portion and coaxially hold at least a spacer of an uppermost stage and a spacer of a lowermost stage among the plurality of stacked spacers.

Structures, such as compressor casings, for reducing a thermal gradient are provided. For example, a compressor case is split such that it includes first and second case segments. The first case segment extends over a first portion of the compressor case circumference and comprises a first inner structure, a first outer structure, and a first porous structure integrally formed as a monolithic component. The first porous structure is defined between the first inner structure and the first outer structure. The second case segment extends over a second portion of the compressor case circumference and comprises a second inner structure, a second outer structure, and a second porous structure integrally formed as a monolithic component. The second porous structure is defined between the second inner structure and the second outer structure. Methods of cooling structures such as compressor casings also are provided.

Rotor systems and methods for improved performance with extended range to stall fabricated through the use of additive manufacturing. A rotor has blades that extend to tips and rotates about an axis. A casing fits over the rotor so that the tips are configured to pass proximate the casing when the rotor rotates. The casing channels a flow stream across the rotor. Grooves are defined in the casing and extend longitudinally at an acute angle relative to the axis. The grooves extend a distance upstream from a leading edge of the blades and over at least a portion of the blade tips so that the blade tips are configured to pass across the grooves when the rotor rotates.

An air-sending device includes a propeller fan to rotate about a rotational axis, and a ducted bell mouth surrounding an outboard area of the propeller fan. The propeller fan includes a plurality of blades. Each of the blades includes, in its outboard portion, a reflexed part bent upstream of an airflow that is generated in the direction of the rotational axis by rotation of the propeller fan. In the propeller fan, within an area that is closer to the trailing edge than is the near mid-chord area, the propeller fan is inclined downstream of the airflow from the inboard edge to the reflexed part. In at least a portion of an area where the cylindrical part of the bell mouth and the outboard edge of each blade face each, the reflexed part has a reflex angle of greater than or equal to 90 degrees.

A motor includes a rotor rotatable about a center axis extending vertically, a stator to rotate the rotor, and a housing covering the rotor and the stator from a radially outer side. The housing includes a first housing located on a first side in the axial direction, and a second housing located on a second side in the axial direction. The first housing includes a first opposing surface opposing the second housing in the axial direction, and a first wall portion extending from the first opposing surface to the second side in the axial direction. The second housing includes a second opposing surface opposing the first housing in the axial direction, a second wall portion extending from the second opposing surface to the first side in the axial direction, and a base portion holding the stator. The first wall portion and the second wall portion oppose each other in a radial direction.

Multistage gas turbine engine (GTE) compressors having optimized stall enhancement feature (SEF) configurations are provided, as are methods for the production thereof. The multistage GTE compressor includes a series of axial compressor stages each containing a rotor mounted to a shaft of a gas turbine engine. In one embodiment, the method includes the steps or processes of selecting a plurality of engine speeds distributed across an operational speed range of the gas turbine engine, identifying one or more stall limiting rotors at each of the selected engine speeds, establishing an SEF configuration in which SEFs are integrated into the multistage GTE compressor at selected locations corresponding to the stall limiting rotors, and producing the multistage GTE compressor in accordance with the optimized SEF configuration.

A fan cowl (1) for receiving at least one fan (2) which is spaced apart relative to a cooler (4), having a fan frame (6) which can be attached to the cooler (4) with at least one cutout (8) for feeding air to an impeller (10) of the fan (2), the cutout (8) having a centered motor receptacle (12) for receiving a fan motor (14) which can be driven electrically, and the cutout (8) being surrounded on the circumferential side by a fan shroud (16). It is proposed that the fan shroud (16) has at least one opening (20) for setting an air pressure distribution which can be generated by way of the fan. A fan arrangement (22), having a fan cowl (1) of this type.