Composite frequency modulation silencer and tuning method thereof

Abstract

The invention provides a composite frequency modulation silencer and a tuning method thereof. The composite frequency modulation silencer comprises a fixing assembly, a micro-perforated assembly and an adjusting assembly, wherein the micro-perforated assembly comprises a micro-perforated pipe, at least two fixing plates and a baffle, the micro-perforated assembly is fixedly arranged in the fixing assembly, the fixing plates are oppositely arranged on the outer side of the micro-perforated pipe, the fixing plates and the micro-perforated pipe are integrally formed, a plurality of rows of through holes are formed in the micro-perforated pipe located between the fixing plates at equal intervals, and the baffle penetrates through the fixing plates, is slidably arranged on the outer side of the micro-perforated pipe and covers the through holes; the adjusting assembly comprises an elastic film and a piezoelectric vibrator which are arranged on the outer sides of the oppositely-arranged fixing plates in a wrapping mode, a resonant cavity I is formed by the elastic film and the outer side of the micro-perforated pipe, and a resonant cavity II is formed by the elastic film and the inner wall of the fixing assembly; the micro-perforated pipe, the resonant cavity I, the elastic film and the resonant cavity II form a closed two-degree-of-freedom silencing system; and the piezoelectric vibrator is arranged on the outer side of the elastic film and is electrically connected with a power supply. According to the composite frequency modulation silencer and the tuning method thereof, the noise control frequency band can be expanded, and effective noise suppression is realized.

Description

technical field [0001] The invention belongs to the technical field of mufflers, and in particular relates to a composite frequency modulation muffler and a tuning method thereof. Background technique [0002] Composite muffler refers to a muffler that combines a resistive muffler and a resistive muffler in a certain way for an airflow duct with noise transmission at the same time. [0003] In the prior art, among the composite mufflers, the perforated tube muffler has a good noise reduction effect in the middle and high frequency range, but in the low frequency range, the perforated tube needs to have a very low perforation rate or increase the volume of the resonant cavity, which not only increases the processing difficulty , cost, and occupied space also increase, which limits the applicable occasions of the perforated tube muffler structure, while the flexible film structure has a better absorption effect on low-frequency noise, and has the advantages of simple structure...

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Problems solved by technology

[0003] In the prior art, among the composite mufflers, the perforated tube muffler has a good noise reduction effect in the middle and high frequency range, but in the low frequency range, the perforated tube needs to have a very low perforation rate or increase the volume of the resonant cavity, which not only increases the processing difficulty , cost, and occupied space also increase, which limits the applicable occasions of the perforated tube muffler structure, while the flexible film structure has a better absorption effect on low-frequency noise, and has the advantages of simple structure, easy preparation, and large deformation, but there are still applications Restrictions, such as the inability to effectively suppress the noise of medium and high frequencies at the same time, are not suitable for strong vibration and sound excitation, high temperature difference, extremely light additional mass and extremely small additional space requirements

For example, the patent notification number CN109139191A discloses a micro-perforated resonant cavity noise reduction structure and APU noise reduction muffler, which adopts a large resonant cavity structure, which greatly reduces the weight of the equipment, increases the structural rigidity, and weakens the APU. The intensity of noise transmitted under working conditions, but its noise control frequency band is fixed, and the noise reduction effect is fixed, so it is impossible to achieve the maximum suppression of noise through tuning

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