Low Frequency Sound Absorption Characteristics of"Horn Shape"Resonance Structure of Train Wind Duct
Test results of train air conditioning noise show that the noise energy is mainly concentrated in the 1/3 octave frequency band of 100～500 Hz,with a notable peak value in the 125 Hz frequency band.Firstly,ac-cording to the significant frequency band of low frequency noise and the dimensions of air duct,a"horn shape"resonance sound absorption structure is proposed.Secondly,to verify the accuracy of the simulation calculation,an experimental sample is produced using 3D printing.Comparisons between the simulation and experimental re-sults demonstrate that the low-frequency sound absorption of the resonant sound absorption structure can be achieved by embedding the"horn"tube into the resonant cavity.The trend of the experimental sound absorption coefficient curve is consistent with the simulation.Finally,the numerical finite element method is used to simu-late variations in the curved tube radius R,curved tube tail radius r1 and curved tube tail straight tube L.By changing R,r1 and L,the absorption band of the structure can be adjusted,and the adjustable resonant fre-quency range is between 70～170 Hz.The results show that compared with the univariate resonant sound absorp-tion structure,the sound absorption performance and frequency band of the"horn shape"resonant sound absorp-tion structure are significantly enhanced by altering the multi-variable resonant sound absorption structure of R,r1 and L,and can be used to absorb low frequency noise of train air conditioning.
train air ductlow frequency noisehorn shapea standing wave tubethe resonance absorption
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