摘要:
A blower and a method for decreasing eddy noise are provided. The blower includes a fan frame, a fan wheel, at least one induction element and a coil. The fan frame has in inlet and an outlet. The fan wheel is disposed in the fan frame and has a wheel hub and a plurality of fan blades connected to periphery of the wheel hub. The induction elements are fixed to the corresponding fan blades, the coil is disposed on the fan frame for driving the at least one induction element, such that the fan blade corresponding to the induction element swing back and forth to generate a vibration sound, and the vibration sound is counteracted with eddy noise generated when the fan wheel rotates. Moreover, the method for decreasing eddy noise is also provided.
摘要:
An aircraft engine sound attenuation apparatus includes a perforated face member (140), a backing member (170), a plurality of connecting members (150) coupling the perforated face member to the backing member to form a plurality of channels (160) spanning from the perforated face member to the backing member, and a bulk absorber (161) disposed in each of the plurality of channels, wherein the plurality of channels are connected to an interior portion of an aircraft engine nacelle component so that the plurality of channels are oriented in a direction substantially normal to a direction of fluid flow pressure drop passing through the aircraft engine.
摘要:
An acoustic liner (3) for a gas turbine engine (10) includes an acoustic structure (35) for the absorption of acoustic excitation and a heat exchanger. The heat exchanger is able to exchange heat across the acoustic structure (35).
摘要:
The invention relates to a method and an apparatus (1) for damping acoustic waves (2) in a fluid which is situated in a volume (3), comprising a cavity (8) which is enclosed by delimiting surfaces (4-7), wherein at least one of the delimiting surfaces (4-7) is permeable to fluid, in order to make fluid exchange with the volume (3) possible, wherein a sound generator (9, 9') is arranged in or on the cavity (8), in order to actively excite acoustic waves (11) which are actively excited in the fluid which is situated in the cavity (8), with the result that damping of the acoustic waves (2) in the volume (3) occurs.
摘要:
A method of surely manufacturing a porous sound absorbing material having low weight and excellent heat resistance enough to be used for the exhaust nozzle of a jet engine, high sound absorbing effect on the noise in wide band from the jet engine, and stable performance without a variation in porosity, comprising the step of forming a frame of the aggregate (5) having pores (6).
摘要:
An array of adaptive or fixed Herschel-Quincke tubes (1) aligned in a circumferential or helical array about an inlet (38) of a turbofan engine. The array of tubes effectively divide the acoustic energy generated by the engine. One of the energy components propagates within the tubes while the other propagates within the engine compartment. The acoustic energy within the tubes is reintroduced into the engine compartment to cancel the acoustic energy remaining in the engine as it propagates from the fan (36) towards the inlet and the outlet (34) openings.
摘要:
The gas turbine engine fan assembly includes an equal number of rotor blades and stator vanes spaced axially therefrom. An annular duct surrounds the blades and vanes and has an inlet for receiving air and an outlet for discharging at least a portion of the air upon compression by the blades. The fan duct further includes a passive acoustic liner tuned for attenuating at least one harmonic noise tone generated by the blades, with a fundamental blade passing frequency noise tone being actively attenuated by a plurality of anti-noise sound transmitters disposed in the fan duct.
摘要:
Bei einem Verfahren zum Minimieren thermoakustischer Schwingungen in Gasturbinenbrennkammern wird eine modulierte Eindüsung von flüssigem oder gasförmigen Brennstoff an der Kopfstufe eines Vormischbrenners durchgeführt.
摘要:
L'invention concerne un dispositif permettant de supprimer les vibrations dues à la combustion dans une chambre de combustion (1), pouvant être l'objet de vibrations acoustiques, d'une installation à turbine à gaz. Ladite chambre de combustion (1) est pourvue d'un brûleur (2) assurant la combustion d'un fluide comportant un combustible, fluide qui est conduit jusqu'au brûleur (2) par une conduite d'alimentation (3) pouvant être l'objet de vibrations acoustiques et couplée acoustiquement à la chambre de combustion (1). Selon un premier mode de réalisation de l'invention, le dispositif présente un élément (4, 5; 6; 7; 19) ayant une action acoustique et couplé à la conduite d'alimentation (3), par lequel la conduite d'alimentation (3) est accordée acoustiquement de telle manière qu'une combustion instationnaire en raison des vibrations acoustiques dans la conduite d'alimentation (3) soit pratiquement exclue. Selon un deuxième mode de réalisation de l'invention, une réaction de vibrations acoustiques dans la conduite d'alimentation (3) à des vibrations acoustiques dans la chambre de combustion (1), réaction induite par une combustion instationnaire en raison des vibrations acoustiques dans la conduite d'alimentation (3) est réglée, par l'élément (4, 5; 6; 7; 19) ayant une action acoustique, de telle manière qu'elle s'oppose à la production de vibrations dues à la combustion. L'application de l'invention est possible et avantageuse dans les installations fixes à turbine à gaz d'une puissance électrique nominale atteignant 100 MW et plus.