Active/passive control Helmholtz resonator capable of changing sound absorption frequency

Abstract

The invention provides an active / passive control Helmholtz resonator capable of changing sound absorption frequency. A heating rod is installed in the resonator, the thermodynamic characteristics of a throat of the resonator are changed, the damping effect of the resonator is improved, the sound absorption frequency of the resonator is changed, and therefore the active / passive control effect of the resonator is achieved. Under different heating powers, the sound absorption capability of the resonator to different frequencies is measured, and it is proved that the heating type Helmholtz resonator can effectively change the sound absorption frequency. The acoustic silencer is suitable for various combustion systems with self-excited combustion oscillation, and an effective means is provided for instable combustion inhibition. Due to the fact that the sound absorption frequency range of a common Helmholtz resonator is very narrow, the size must be redesigned to adapt to different sound absorption frequencies, the sound absorption frequency of the heating type Helmholtz resonator can be adjusted under the condition that the size is not changed, and the heating type Helmholtz resonator has the advantages of being high in flexibility, easy to operate and the like.

Description

technical field [0001] The invention relates to an active / passive control Helmholtz resonator that changes the sound absorption frequency, and realizes the absorption of sound waves of different frequencies by changing the heating power. Stabilized combustion suppression provides an effective means. Background technique [0002] Combustion instability has always been a worldwide problem restricting the development of various combustion systems with self-excited combustion oscillations, such as aeroengines, gas turbines, and rocket engines. In order to suppress pressure fluctuations and reduce noise, a passive control device with a damping effect is generally used, and a Helmholtz resonator is an acoustic device composed of a thin neck and a cavity. Dissipation realizes the absorption of sound waves, and has been widely used in the field of acoustic dampers due to its relatively simple structure. When the resonance of the resonator occurs, the fluid periodically compresses ...

AI Technical Summary

Problems solved by technology

[0003] At present, the resonance frequency of the Helmholtz resonator used for unstable combustion control is determined by its size and structure, and its sound absorption frequency range is very narrow. To achieve the task of absorbing sound waves of different frequencies, the size and structure need to be redesigned, which is not only inconvenient Fast implementation also results in waste of materials

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