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The Effect of Length on the Acoustic Attenuation Performance of Concentric Expansion Chambers: An Analytical, Computational, and Experimental Investigation
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Abstract
Expansion chambers are widely used in the breathing systems of engines due to their desirable broadband noise attenuation characteristics. Following an earlier analytical and computational work of Sahasrabudhe et al. (1992), the present study investigates the effect of the length on the acoustic attenuation performance of concentric expansion chambers. Three approaches are employed to determine the transmission loss: (1) a two-dimensional, axisymmetric analytical solution; (2) a three-dimensional computational solution based on the boundary element method; and (3) experiments on an extended impedance tube setup with nine expansion chambers fabricated with fixed inlet and outlet ducts, fixed chamber diameters, and varying chamber length to diameter ratios from 
to 3.53. The results from all three approaches are shown to agree well. The effect of multi-dimensional propagation is discussed in comparison with the classical treatment for the breakdown of planar waves. The study also provides a simple relation for the number of repeating attenuation domes prior to the domination of higher order modes in terms of the l/d ratio of the expansion chamber.
to 3.53. The results from all three approaches are shown to agree well. The effect of multi-dimensional propagation is discussed in comparison with the classical treatment for the breakdown of planar waves. The study also provides a simple relation for the number of repeating attenuation domes prior to the domination of higher order modes in terms of the l/d ratio of the expansion chamber.Recommended Content
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Citation
Selamet, A. and Radavich, P., "The Effect of Length on the Acoustic Attenuation Performance of Concentric Expansion Chambers: An Analytical, Computational, and Experimental Investigation," SAE Technical Paper 950544, 1995, https://doi.org/10.4271/950544.Also In
Applications and Developments in New Engine Design and Components
Number: SP-1071; Published: 1995-02-01
Number: SP-1071; Published: 1995-02-01
References
- 1990 “Standard test method for impedance and absorption of acoustical materials using a tube, two microphones and a digital frequency analysis system.” American Society for Testing and Materials Philadelphia, PA
- Chung, J. Y. Blaser, D.A. 1980 “Transfer function method of measuring in-duct acoustic properties: I Theory.” Journal of the Acoustical Society of America 68 3 907 913
- Ciskowski, R. D. Brebbia, C.A. Boundary Element Methods in Acoustics Computational Mechanics Publications Boston 1991
- Craggs, A. 1976 “A finite element method for damped acoustic systems: an application to evaluate the performance of reactive mufflers.” Journal of Sound and Vibration 48 3 377 392
- Davis, D. D. Stokes, G. M. Moore, D. Stevens, G. L. 1954 “Theoretical and experimental investigations of mufflers with comments on engine exhaust muffler design.”
- El-Sharkawy, A.I. Nayfeh, A.H. 1978 “Effect of an expansion chamber on the propagation of sound in circular ducts.” Journal of the Acoustical Society of America 63 3 667 674
- Eriksson, L.J. 1990 “Higher order mode effects in circular ducts and expansion chambers.” Journal of the Acoustical Society of America 68 2 545 550
- Ih, J. Lee, B. 1985 “Analysis of higher-order mode effects in the circular expansion chamber with mean flow.” Journal of the Acoustical Society of America 77 4 1377 1388
- Kinsler, L. E. Frey, A. R. Coppens, A.B. Sanders, J. V. Fundamentals of Acoustics John Wiley & Sons New York 1982
- Miles, J. 1944 “The reflection of sound due to a change in cross section of a circular tube.” Journal of the Acoustical Society of America 16 1 14 19
- Rayleigh, L. The Theory of Sound, Volume II Dover Publications New York 1945
- Sahasrabudhe, A.D. Munjal, M.L. Ramu, S.A. 1992 “Design of expansion chamber mufflers incorporating 3-D effects.” Noise Control Engineering Journal 38 1 27 38
- Selamet, A. Dickey, N.S. 1994 “The Herschel-Quincke tube: a theoretical, computational, and experimental investigation.” Journal of the Acoustical Society of America 96 5 3177 3185
- Selamet, A. Dickey, N.S. Radavich, P.M. 1994 “Theoretical, computational and experimental investigation of Helmholtz resonators: one-dimensional versus multi-dimensional approach.” SAE 940612