Methods and systems are provided for a noise mitigating device for a turbocharger compressor. In one example, the noise mitigating device includes a set of perforated rings arranged in a recirculation passage of a compressor casing treatment. The rings of the set of perforated rings may be oriented so that apertures of one ring are offset from apertures of one or more adjacent rings, forcing air to flow through the apertures via a non-linear path while deflecting at least a portion of sounds waves generated in the compressor.

An aircraft engine includes a rotating structure and a casing circumferentially surrounding the rotating structure. The aircraft engine further includes an acoustic panel for noise reduction circumferentially surrounding the rotating structure and disposed adjacent the casing. The acoustic panel comprises a plurality of acoustic panel members arranged adjacent to one another to form a substantially complete ring of the acoustic panel. A first acoustic panel member of the plurality of acoustic members is adjacent to a second acoustic panel member of the plurality of acoustic members. The first acoustic panel member is removably secured to the second acoustic panel member by a releasable fastening assembly.

A fan has an impeller (20) that is equipped with blades (26, 28, 30, 32, 34; 58). The blades are configured so that the blade loading of individual blades differs during operation. As a result of this variable blade loading, the frequencies associated with the blade-passing noise (BPF) of the fan can be distributed over a broader frequency spectrum, and thus have a less obtrusive effect.

An air-blowing device has a blower fan that is an axial fan located on a downstream side of a heat exchanger in an airflow direction and supplies air to the heat exchanger and a shroud that supports the blower fan and forms an air passage extending from the heat exchanger to the blower fan. At least one side of a periphery of the heat exchanger is arranged to overlap with an outermost peripheral portion of the blower fan that is outermost in a radial direction of the blower fan when viewed in the airflow direction. The shroud has an air-introduction part that is (i) disposed, in a portion in which the ring part and the connection part connect to each other, on a surface of the connection part facing the heat exchanger and (ii) formed concentrically to be centered at a rotational axis of the blower fan. A part of the air-introduction part protrudes outwardly from a periphery of the connection part in the radial direction of the blower fan when viewed in the airflow direction. A protruding part is provided in the connection part on a boundary between the air-introduction part and a portion other than the air-introduction part.

A side-channel blower for an internal combustion engine includes a flow housing, an impeller which rotates in the flow housing, a drive unit which drives the impeller, a housing wall with a radially delimiting housing wall, impeller blades arranged in a radially outer region of the impeller, a radial gap arranged between the impeller and the housing wall, an inlet, an outlet, and two flow channels. The housing wall radially surrounds the impeller. The impeller blades open in a radially outward direction. The two flow channels connect the inlet to the outlet and are fluidically connected to one another via intermediate spaces between the impeller blades. An interruption zone is arranged between the outlet and the inlet which interrupts the two flow channels in a peripheral direction. A radial interrupting gap is arranged between the impeller and the radially delimiting housing wall in the entire interruption zone.

The invention refers to a fan system (10) comprising a fan shroud (14) and a ring fan (12) having a hub (30), a plurality of fan blades (32), and a ring structure (34). The ring structure (34) has a ring member (46) and a flange member (48), the ring member (46) having a hollow cylindrical shape, the flange member (48) extending radially outwardly from the ring member (46). The fan shroud (14) has an annular shroud flange (54), a shroud body (56) and a plurality of shroud guide vanes (58), the shroud flange (54) extending radially outwardly from the shroud body (56) and being disposed along the rotary axis (A) between the flange member (48) and the shroud body (56), the shroud body (56) being disposed about the ring member (46) and having a first body portion (70), a second body portion (72) and a divergent nozzle (74). A recirculation throttle (88) is formed by the shroud body (56) and the ring member (46) at a location where the first and second body portions (70, 72) of the shroud body (56) intersect one another. The divergent nozzle (74) and a trailing end (50) of the ring member (46) cooperate to form a dynamic sealing feature (90).

A silencing device includes: a flow path forming plate having a flow path forming surface for forming a wall surface of a flow path through which fluid flows; and a cavity defining portion for defining a cavity on the reverse surface side of the flow path forming plate, the reverse surface being located on the reverse side of the flow path forming surface. The flow path forming plate has formed therein a plurality of fine through-holes which are configured to provide communication between the flow path forming surface and the reverse surface and which has a diameter from 0.01 mm to 0.5 mm.

A modular fan cover assembly for inclusion on an electric motor is selectively configurable for degrees of reduced noise operation. The modular fan cover assembly includes a plurality of cooperating components arranged to direct fluid communication through the assembly. The components may include, for example, a fan cover defining a fan chamber for enclosing the fan, an inlet cover including an inlet chamber and a plurality of inlet apertures, and a silencing insert selectively includable with the fan cover assembly that may include one or more silencing features. The selective combination of the components can redirect airflow through various turns or bend in the modular fan cover assembly to trap or suppress noise propagating from the electric motor. The modular fan cover assembly may be operatively equipped with a blower assembly.

A disclosed centrifugal blower comprises: a centrifugal fan; a scroll casing which is configured so as to surround the centrifugal fan, has an air inlet on at least one surface thereof, has an air outlet on one side thereof, and guides, to the air outlet, air discharged from the centrifugal fan; an expansion part which is provided at the air outlet and is configured such that the cross-sectional area of the flow path is expanded in the air discharge direction; and a dividing plate which is provided in the expansion part, is arranged at the outside of the air outlet and is arranged lengthwise along the flow direction of the air discharged from the air outlet.

The invention relates to a flow-conducting grille designed as a pre-conducting grille for arranging on a suction region of a fan, wherein the flow-conducting grille has a grille web structure about an axial center line, which grille web structure comprises radial webs spaced apart in the circumferential direction and coaxial circumferential webs spaced apart in the radial direction and an outer ring, wherein an inflow side of the flow-conducting grille extends flat and parallel to a radial plane of the flow-conducting grille.