Disclosed are a centrifugal fan blade assembly and a centrifugal fan, comprising a plurality of blades, a blade leading edge of at least some of the blades being provided with an interference groove, the interference groove extending in a width direction of the blade. By providing the interference groove extending in the width direction of the blade on the blade leading edge, when the fan blade assembly is running, the interference groove changes noise frequency, thereby preventing the blade leading edge from producing a relatively large broadband noise after being impacted by a high speed air flow, thus effectively reducing noise.

A composite component comprising fibres embedded in a matrix material. A plurality of pins extend through the matrix material. Each pin of the plurality of pins comprises a hollow bore such that the bore of each pin defines a plurality of holes in the composite component.

Acoustic structures in which acoustic septa are located in the angled cells of a honeycomb for reducing the noise generated from a source. The honeycomb used to form the acoustic structure has cell walls that extend at an angle relative to the honeycomb edges such that the depth of the honeycomb cells is greater than the honeycomb core thickness The acoustic septa are formed by inserting planar acoustic inserts into the angled honeycomb cells to form septum caps which are friction-locked within the angled cells and then permanently bonded in place.

A centrifugal blower assembly with reduced recirculation losses includes a housing defining an interior space and at least one inlet ring coupled to the housing to define an inlet into the interior space. The centrifugal blower assembly also includes an impeller configured to rotate about an axis to channel an airflow through the inlet and within the interior space. The impeller includes a plurality of blades that each include a notch formed therein, wherein the notch is radially aligned with the at least one inlet ring.

A system includes an inlet duct disposed about an inlet axis, wherein the inlet duct is configured to direct an airflow along the inlet axis to a compressor inlet. The inlet includes an inlet heating system and a heating portion having a longitudinal axis that is substantially perpendicular to the inlet axis. The inlet heating system includes a first conduit substantially parallel to the longitudinal axis that is configured to distribute a heated fluid directly to the airflow via a first set of openings of a first end zone of the first conduit and a second set of openings of a second zone of the first conduit. The first end zone is configured to receive the heated fluid from a heating source, the second zone is coupled to the first end zone, and the second zone is configured to receive the heated fluid from the first end zone.

An air-blowing device 10A includes an air blower 50 and a housing 20 that includes an intake hole 41a into which a fluid flows as a result of the air blower 50 being driven and an exhaust portion from which the fluid is discharged as a result of the air blower 50 being driven and that accommodates the air blower 50. The housing 20 is capable of expanding and contracting so as to change the internal volume of the housing 20.

A fan system is used for dissipating heat of an electronic device. The fan system includes a fan, a hollow structure, and a control circuit. Sound waves made by the fan are transmitted to an interior of the hollow structure when the fan is operating. The control circuit is connected to the hollow structure and is configured to control deformation/deformations of the hollow structure according to a state/states of the fan and/or the electronic device, which change a volume of the interior of the hollow structure for making a resonance frequency of the hollow structure being approximate to a rotation speed of the fan or being the same as the rotation speed of the fan.

A turbofan engine includes a core engine, a fan, a fan bypass duct partially surrounding the core engine and the fan, and a bleed system. The bleed system includes a first bleed circuit configured to bleed pressurized air from the core engine and channel the flow to a first circuit of a heat exchanger, and a second bleed circuit configured to bleed fan air from the fan bypass duct and channel the flow to a second circuit of the heat exchanger. The second bleed circuit includes a bleed duct including a duct inlet and a duct outlet coupled in flow communication with the heat exchanger through a valve. The bleed duct also includes an acoustic suppression conduit extending from the bleed duct upstream of the valve to the fan bypass duct and sized to suppress pressure oscillations inside the second bleed circuit when the valve is at least partially closed.

A fan has a fan housing and an impeller mounted in the fan housing. The fan housing has a main case, and a foamed metal plate securely mounted in an air inlet of the main case. Hot air inhaled into the main case is forced to flow through pores in the foamed metal plate. Thus, heat in the hot air is conducted to the foamed metal plate and then to the main case. The heat in the hot air is dissipated to reduce temperature of the hot air in advance. Accordingly, heat dissipation efficiency of the fan is improved. Since the foamed metal plate hinders flow of the hot air, the hot air flowing into the main case is reduced. Therefore, air pressure and flowing speed of the hot air flowing into the main case is reduced, such that noise made by the fan is also reduced.

A centrifugal fan with dual outlets in the same direction includes a fan frame, an impeller, and a motor. The fan frame includes an upper cover, a base plate and a first air deflector. The base plate and the upper cover are connected to form an accommodating space and an air outlet plane. The first air deflector is arranged near the air outlet plane and divides the air outlet plane into a first air outlet and a second air outlet. The impeller is disposed in the accommodating space. The impeller and the side wall of the fan frame form a flow channel therebetween. The motor is connected to the impeller and drives it to rotate. The first air deflector extends inward of the flow channel from the air outlet plane and the end of the first air deflector has a first guide portion, which is a slanted surface.