A fan structure includes a frame body and a fan impeller. The frame body has a base seat and an annular wall. A bearing cup upward extends from a center of the base seat. At least one groove is annularly formed on inner wall face of the annular wall. The fan impeller is pivotally disposed in the bearing cup and has a hub and multiple blades outward extending from the hub. Each blade has an end edge. At least one protrusion section outward protrudes from the end edge into the groove. According to the design of the fan structure, the protrusion section can destroy the production of the vortex of the blade of the conventional fan so as to greatly minify the strength of the vortex. Therefore, the structure of the sound field of the vortex is changed so that the noise of the fan structure is lowered.

An inlet bleed heat (IBH) system for use in a turbine engine including a silencer assembly. The inlet bleed heat (IBH) system includes a feed pipe for delivering compressor discharge air. The feed pipe includes a plurality of orifices along at least a portion of a length of the feed pipe, and each orifice of the plurality of orifices extends through a wall of the feed pipe for allowing the compressor discharge air to exit the feed pipe. The system also includes a heat shielding component that extends across the feed pipe, wherein the heat shielding component is configured to reduce heat transfer between the feed pipe and the silencer assembly of the turbine engine.

A gas turbine engine comprises a fan rotor having fan blades received within an outer nacelle, and the outer nacelle having an inner surface. The outer nacelle is secured to an inner portion through a mount flange at a first axial location. An acoustic treatment extends inwardly of the outer portion of the nacelle and across the axial location of the mount flange and further inwardly toward the fan blades.

An air-sending device includes a housing including an inlet air passage communicating with an air inlet and an outlet air passage communicating with an air outlet, a first partition plate partitioning an interior of the housing into the inlet air passage and the outlet air passage, a bell mouth disposed around an opening defined in the first partition plate, and an impeller disposed over the first partition plate across the bell mouth and having a rotation axis that extends in a direction that intersects the first partition plate. The impeller suctions air into the inlet air passage from the air inlet, and blows out air from the air outlet through the outlet air passage. The inlet air passage guides air from the air inlet to the opening along the first partition plate, and has an air-passage wall.

An air filtration system is described that is suited for CBRN and ColPro applications, and has an integrated inertial particle separator (IPS) and scavenge fan blower as a pre-dust/particle filter, a variable speed fan blower, and a filter housing that mounts two gas-particulate filter sets. The variable speed fan blower, managed by a motor control unit and motor speed algorithm, automatically adjusts its speed to maintain constant air flow regardless of its altitude.

A method of designing a gas turbine engine comprises the steps of including a fan section with a fan. A turbine section is included having a first turbine and a high pressure turbine. A gear reduction is included between the fan and the first turbine, the gear reduction being configured to receive an input from the first turbine and to turn the fan at a lower speed than the first turbine in operation. The first turbine is designed to include a number of turbine blades in each of a plurality of rows of the first turbine, the first turbine blades operating at least some of the time at a rotational speed, and the number of blades and the rotational speed being such that the following formula holds true for at least one of the blade rows of the first turbine: (number of bladesspeed)/605500.

An air conditioner includes a cross-flow fan having a cylindrical shape, and a heat exchanger disposed on an upstream side of an air flow of the cross-flow fan. The cross-flow fan includes a plurality of impellers. Each of the impellers includes a plurality of blades arranged in a circumferential direction. A clearance is formed between the cross-flow fan and the heat exchanger. The clearance has a dimension no more than 20% of a diameter of each of the impeller. The impellers are arranged with at least one of the blades displaced between each adjacent two of the impellers. A number of the impellers arranged along a rotation axis is at least 14 and no more than 30 in the cross-flow fan.

The invention relates to an electric machine (1) comprising noise-reducing means (24) designed so as to obtain a resonance frequency of the electric machine within a resonance frequency range that does not match the range of frequency of the harmonics of the electric machine, more precisely between 1500 Hz and 2500 Hz.

A gas turbine engine comprises a fan rotor having fan blades received within an outer nacelle, and the outer nacelle having an inner surface. At least a portion of the nacelle inner surface extends radially inwardly to be radially inward of an outer diameter of the fan blades. The inner surface of the nacelle is formed with a trench, which extends into the inner surface to a radially outer extent that is spaced radially outward of the outer diameter of the fan blades.

A centrifugal blower includes a centrifugal fan having a main plate and a side plate facing each other in a direction of a rotation axis, and a casing to house the centrifugal fan. The casing has a peripheral wall extending along an outer circumferential edge of the centrifugal fan, and has a tongue portion at a position on the peripheral wall. A distance between the outer circumferential edge of the centrifugal fan and the tongue portion is smaller on the main plate side of the centrifugal fan than on the side plate side of the centrifugal fan.