An Active/Passive Controlled Helmholtz Resonator for Changing Sound Absorption Frequency
A resonator and sound-absorbing technology, which is applied in the direction of sound-emitting devices and instruments, can solve the problems of narrow range, waste of materials, inconvenient and quick realization, etc., and achieve the effects of low cost, changing sound-absorbing frequency, and simple structure
Active Publication Date: 2022-05-10
BEIHANG UNIV
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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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[0025] The present invention will be described in detail below in conjunction with the accompanying drawings. In this embodiment, by changing the heating power, the sound absorption frequency of the resonator is effectively changed, and the specific implementation is described as follows:
[0026] In this embodiment, under normal temperature and pressure, the boundary conditions of the pipeline outlet are respectively set as open and closed conditions, and the influence of the change of heating power on the sound absorption frequency under different boundary conditions of the pipeline is studied. Under the condition that the outlet of the pipeline is open, the four small holes around the cavity above the resonator are closed, and the flow of different speeds is introduced into the pipeline, and the influence of the change of heating power on the sound absorption frequency under different flow velocities of the pipeline is studied; Under the condition that the outlet of the pip...
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The present invention proposes an active / passive control Helmholtz resonator that changes the sound absorption frequency. The invention installs a heating rod in the resonator, changes the thermodynamic characteristics of the throat of the resonator, increases the damping effect of the resonator, and changes the sound absorption frequency of the resonator, thereby realizing the active / passive control effect of the resonator. Under different heating powers, by measuring the sound absorption ability of the resonator for different frequencies, it is proved that this type of heating Helmholtz resonator can effectively change the sound absorption frequency. As an acoustic muffler, the invention is applicable to various combustion systems with self-excited combustion oscillations, and provides an effective means for suppressing unstable combustion. Since the sound absorption frequency range of the general Helmholtz resonator is very narrow, the size must be redesigned to adapt to different sound absorption frequencies, and the heating type Helmholtz resonator proposed by the present invention can adjust the sound absorption frequency without changing the size, so the invention It has the advantages of strong flexibility and easy operation.
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 ...
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IPC IPC(8): G10K11/172
CPCG10K11/172
Inventor 李敬轩朱烁烁方珅刘腾宇孟羽倩李培烁于泽熙
Owner BEIHANG UNIV