A spiral housing of a radial fan has a flow cross-sectional area which, starting from a housing tongue, increases in the circumferential direction, around a fan impeller which can be arranged on an axial central axis. The cross-sectional area is determined via a contour of at least one axial side part of the spiral housing. The one axial side part has an axial suction opening with an opening edge section surrounding the suction opening, which is directly adjoined, viewed in the radial direction, by a transition section extending in the circumferential direction. The transition section, in a starting section which extends from the housing tongue in the circumferential direction over a predetermined angle, is spaced apart in the axial direction relative to the opening edge section and has a course which increases the flow cross section in the circumferential direction until axial surfaces of the opening edge section and of the transition section extend in the same plane.

A gas turbine engine includes a fan section having a single-stage fan, a core turbine engine, and a nacelle at least partially surrounding the fan of the fan section and the core turbine engine. The gas turbine engine also includes an outlet guide vane extending between a casing of the core turbine engine and the nacelle. The gas turbine engine is configured to define an acoustic ratio greater than or equal to 2.3, with the acoustic ratio being a ratio of an axial spacing between the trailing edge of the fan blade and the leading edge of the outlet guide vane at a radial location seventy-five percent (75%) along the span of the fan blade to the axial width of the fan blade also at the radial location seventy-five percent (75%) along the span of the fan blade.

A blower (100) may include a housing (110), a motor (120), a fan assembly (170) and an inlet assembly (160). The housing (110) may include a handle (140) operably coupled thereto. The fan assembly (170) may be operably coupled to the motor (120) to force air through a blower tube (150) responsive to operation of the motor (120). The blower tube (150) may define a tube axis (152). The inlet assembly (160) may provide a path for air to the fan assembly (170). The inlet assembly (160) may include an inlet aperture (162) formed at an end of the housing (110). The inlet assembly (160) may further include an inlet mesh (164) disposed within the housing (110) spaced apart from the inlet aperture (162).

A centrifugal blower apparatus includes a scroll-shaped housing with first and second air inlets which open to a blower chamber that is in fluid communication with an air outlet. The blower includes a motor to drive impellers, wherein the motor is secured to a frame coupled within the housing in a manner to substantially enhance aerodynamic performance of the blower.

A blower for a breathing apparatus has a diffuser for increasing static pressure and/or reducing noise and/or mitigating pressure instabilities and/or managing reverse flow.

A control device is provided with a control section that operates an apparatus on board a vehicle and controls a first frequency, which relates to an operation sound of the apparatus, such that the first frequency corresponds with a second frequency, which relates to an ambient sound in the vehicle.

A fan for cooling an electronic device is described, wherein the fan can include an enclosure and a motor secured within the enclosure. The fan can also include an impeller to be turned by the motor, the impeller having a plurality of blades, wherein an angular spacing of the blades results in an audio spread-spectrum within a range of audio frequencies. In some examples, an arrangement of the blades has a center of mass below a threshold, and the angular spacing of the blades and a blade pass frequency (BPF) results in sound that is distributed in the range of audio frequencies.

A motor-fan assembly includes a motor assembly having a tubular core with a rotatable shaft extending therethrough. The assembly includes a working fan assembly which has at least one working fan rotated by the rotatable shaft. A blower housing separates the motor assembly from the working fan assembly, wherein the rotatable shaft extends through the blower housing.

A fan blade unit and a fan impeller structure thereof. The fan blade unit includes a main body having a root section and an end section. The root section is connected with a hub. The end section extends in a radial direction away from the hub. The end section defines a first direction and a second direction. Multiple protrusion bodies are disposed at the end section and at least one channel is formed between the protrusion bodies. The channel extends in the first direction. The fan blade unit is applied to the fan impeller structure. When the fan impeller rotates, a high-pressure area is created between the channel and the wall of the outer frame of the fan, whereby the airflow is restrained from turning over from the lower wing face to the upper wing face to generate wingtip vortex.

A fan assembly, and associated methods are shown that may include tapering configurations in a nozzle assembly. Configurations are shown that are optimized for thrust. Examples of assemblies and methods are shown that include sound attenuating materials and jagged edges to reduce noise. Configurations are shown that provide a substantially constant or increasing air velocity. Configurations are also shown that provide a static pressure of 120 percent or less of a given dynamic pressure.