The suction unit comprises: a cover having an air inlet; a noise reduction part provided in the cover, arranged outside the air inlet and spaced therefrom; an impeller for flowing the air which has passed through the noise reduction part and then the air inlet; a motor having a rotating shaft connected to the impeller; a guide apparatus for guiding the flow of the air which has flown from the exit of the impeller; and a shaft coupling part coupled to the rotating shaft connected to the impeller.

A fan (radial or axial fan), with an impeller and with a preguide device in the flow path in front of the impeller, preferably in front of the inlet region of an inlet nozzle, has the preguide device as a preguide grid with webs and/or guide vanes which are arranged and shaped such that flow influencing in the circumferential direction occurs for a substantially swirl-free inflow.

A system includes an airfoil disposed inside an engine assembly that includes a pressure side and a suction side that are coupled together at a leading edge and a trailing edge. The airfoil extends a radial length away from a central axis of the engine assembly between a hub end and a tip end. The airfoil includes a sweep feature disposed at the leading edge that is shaped to alter the air inside the engine assembly. Altering the air inside the engine assembly reduces a surface unsteady pressure level on the airfoil. The system includes a fan frame assembly comprising an inner and outer surface. The hub end is coupled with the inner surface and the tip end is coupled with the outer surface. The airfoil is integrated with the fan frame assembly such that the airfoil increases a structural load supporting capability of the fan frame assembly.

A profiled structure for an aircraft or turbomachine is elongated in a direction in which the structure has a length exposed to an airflow and includes serrations defined by successive teeth and depressions. The serrations may be transverse to a leading edge and/or a trailing edge of the profiled structure and in the direction of elongation. Along the profiled leading edge and/or profiled trailing edge, the successive teeth and depressions may extend only over a part of the length exposed to the flow. The amplitude and/or spacing of the teeth may vary monotonically except for the few teeth nearest each end of the part, with a remaining part of the length being smooth.

Provided are a blower, capable of suppressing noise occurring in a stator while significantly improving blowing efficiency, and an outdoor unit using the same. The present disclosure comprises: a bell mouth part spaced apart at a predetermined distance in the radial direction with respect to an outer circumferential end of a propeller fan; and a diffuser part installed on the downstream side of the bell mouth part, and having a flow path area which is enlarged from the upstream side toward the downstream side with a larger magnification rate than the magnification rate of the flow path area in the downstream end of the bell mouth part; and a stator part having a plurality of stators, wherein the stator part is arranged within the diffuser part.

An outdoor cooling unit for vehicular air conditioning apparatus includes: a casing including an outlet section, inlet sections having an inlet plane inclined; a first heat exchanger facing one of the inlet sections and a second heat exchanger facing an other of the inlet sections; at least one propeller fan below the outlet section to blow out air upwardly. An angle formed between the normal line to the inlet plane and the z axis is an acute angle. Each of the blades includes a blade chord center point on an inner peripheral end thereof and an other blade chord center point on an outer peripheral end thereof, positioned so that a line segment connecting therebetween has an inclination to the outlet section proportionally to closeness to outer periphery of the blade. A blade chord center line forms a curve being convex toward the outlet section across the entire area.

Methods and systems are provided for mitigating noise generated by a compressor operating at low flow rates. A swirl device with two concentric flow passages upstream of the compressor directs intake air flow to the compressor through two different flow paths, depending on air flow rates. Angled swirl vanes at an outlet of the swirl device pre-whirl the air flowing to the compressor to reduce noise generation at low air flow rates.

A passive transpirational flow acoustic liner assembly for a gas turbine engine includes a guide vane assembly and a conduit configured to deliver airflow received from the guide vane. The guide vane assembly includes an airfoil having a transpirational flow acoustic liner. The acoustic liner includes a face sheet defining a portion of an outer surface of the airfoil and having a plurality of first apertures, a segmented member coupled to the face sheet and having a plurality of chambers in fluid communication with the outer surface via the plurality of first apertures, a backing sheet having a plurality of apertures and being coupled to the segmented member such that the segmented member is positioned between the face sheet and the backing sheet, and a plenum coupled to the backing sheet opposite the segmented member and fluidly connected to the conduit.

A climate-control system may include a compressor and a control module. The compressor includes a motor driving a compression mechanism to compress a working fluid. The control module is in communication with the motor and may be configured to determine a balance speed of the motor at which a forward-rotational inertial force of the compression mechanism is equal to a backward-rotational gas force on the compression mechanism. The control module may be configured to adjust a running speed of the motor to the balance speed after receipt of a compressor-shutdown-command and before shutting down the compressor.

A humidification and air cleaning apparatus is provided, in which a wave having a predetermined cycle is formed on a plurality of blades of a blower fan, such that operating noise caused by a flow of discharged air may be minimized, and a wave is formed at a trailing edge, such that a phase difference may be formed for air to be separated, and air flow noise of the discharged air may be reduced.