Adaptive-Passive Quarter-Wave Tube Resonator Silencer
نویسندگان
چکیده
An adaptive-passive quarter-wave tube resonator silencer was experimentally tested using recorded in-duct reciprocating engine exhaust noise. The exhaust noise was re-played through a loudspeaker attached to one end of a duct, and the adaptive passive system was able to track changes in engine speed and provide attenuation of the noise at the fundamental firing frequency of the engine and the third harmonic. The control system used a novel method of determining the phase angle of the transfer function between the pressure in the quarter wave tube and the main duct by using a sliding-Goertzel algorithm to calculate the Fourier coefficients.
منابع مشابه
An effective silencer design for artificially air conditioned environment.
An effective silencer for an air conditioning duct is studied. A duct with an acoustically soft boundary is employed as an effective silencer. On the acoustically soft boundary the sound pressure is zero and it is impossible to realize such boundary in the air-borne sound field, because of the non-existence of a much lighter medium than the air. In this study, the arrangement of one-quarter wav...
متن کاملAcoustic attenuation of hybrid silencers
The acoustic attenuation of a single-pass, perforated concentric silencer filled with continuous strand fibers is investigated first theoretically and experimentally. The study is then extended to a specific type of hybrid silencer that consists of two single-pass perforated filling chambers combined with a Helmholtz resonator. One-dimensional analytical and three-dimensional boundary element m...
متن کاملA Sliding Goertzel Algorithm for Adaptive Passive Neutralizers
A common method used in tuning adaptive-passive tuned vibration neutralizers is to adjust its resonance frequency to match the excitation frequency, which has the characteristic that the phase angle between its vibrating mass and its support is −90 degrees. A sliding-Goertzel algorithm is presented and demonstrated for extracting the vibration signals at the frequency of interest. The benefit o...
متن کاملAcoustic Characteristics of Coupled Dissipative and Reactive Silencers
The acoustic characteristics of a hybrid silencer consisting of two dissipative chambers and a Helmholtz resonator are investigated first computationally and experimentally. Complex wave number and characteristic impedance are used for the dissipative chambers to account for the wave propagation through absorbing material. Three-dimensional boundary element method (BEM) is employed to predict t...
متن کاملNoise reduction using a quarter wave tube with different orifice geometries
It is well known that the acoustic performance of silencing elements decreases with an increase in exhaust gas flow. Tests were conducted on three orifice geometries of side-branches on an adaptive quarter-wave tube to determine which was the least compromised by the high-speed exhaust gas passing over the side-branch. The side-branch geometries that were tested were a sharp edge, a backward in...
متن کامل