Micro-perforated resonant cavity muffling structure and noise-reduction muffler for auxiliary power units (APU)

Abstract

The invention discloses a micro-perforated resonant cavity muffling structure and a noise-reduction muffler for auxiliary power units (APU). The micro-perforated resonant cavity muffling structure comprises an inner cylinder assembly and an outer cylinder; the outer cylinder is in a hollow cylinder shape, a cavity is formed in the outer cylinder, and through openings leading into the outer cylinder are formed in the two ends of the outer cylinder; the inner cylinder assembly penetrates through the outer cylinder through the through openings and is fixedly connected with the outer cylinder through a plurality of structures; a plurality of muffling through holes are formed in the inner cylinder assembly, muffling partition plates serve as supporting structures, the muffling partition platesare circular partition plates, the muffling partition plates and the inner cylinder assembly are coaxially arranged, and the outer edges of the muffling partition plates are fixedly connected with theinner wall of the outer cylinder; and the inner cylinder assembly comprises a plurality of muffling acoustic liners which are sequentially connected end to end, the muffling partition plates are coaxially arranged outside the junctions of all the muffling acoustic liners, and muffling through holes are formed in all the muffling acoustic liners. According to the micro-perforated resonant cavity muffling structure, the structure form of a large resonant cavity is adopted, the weight of equipment is greatly decreased, structure stiffness is improved, and the intensity of noise transmitted in aworking state of the APU is weakened.

Description

technical field [0001] The invention relates to the technical field of aeronautical engineering machinery, in particular to a micro-perforated resonant cavity noise reduction structure and a noise reduction muffler for an APU. Background technique [0002] APU (Auxiliary Power Units, Auxiliary Power Units) refers to a small power unit specially installed on an aircraft to independently output compressed air or supply power outside the main power unit (engine). Usually a specially designed small turboshaft engine. Including power output shaft, compressed air extraction device and automatic control device, etc. Before take-off, provide compressed air or power supply to the aircraft to start the main engine, reducing the aircraft's dependence on airport equipment; during take-off, provide compressed air for the aircraft air-conditioning system, and provide electricity for the grid to reduce the power consumption of the main engine and improve take-off performance ; During f...

AI Technical Summary

Problems solved by technology

However, the inner diameter of the middle section of this prior art is larger than that of the front section and the rear section, thereby reducing the exhaust velocity, and causing damage to the equipment when the exhaust volume is too large

And this prior art structure is complicated, and weight is bigger

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