An Assessment of High-Order-Mode Analysis and Shape Optimization of Expansion Chamber Mufflers
In this paper, the acoustical model of the expansion chamber muffler will be established by assuming that it is a rigid rectangular tube driven by a piston along the tube wall. Using an eigenfunction (higher-order-mode analysis), a four-pole system matrix for evaluating acoustic performance (STL) is derived. To improve the acoustic performance of the expansion chamber muffler, three kinds of expansion chamber mufflers (KA-KC) with different acoustic mechanisms are introduced and optimized for a targeted tone using a genetic algorithm (GA). Before the optimization process is performed, the higher-order-mode mathematical models of three expansion chamber mufflers (A-C) with various allocations of inlets/outlets and various chambers are also confirmed for accuracy. Results reveal that the STL of the expansion chamber mufflers at the targeted tone has been largely improved and the acoustic performance of a reverse expansion chamber muffler is more efficient than that of a straight expansion chamber muffler. Moreover, the STL of the expansion chamber mufflers will increase as the number of the chambers that separate with baffles increases.
ABOM, M. (1990), Derivation of four-pole parameters including higher order mode effects for expansion chamber mufflers with extended inlet and outlet, Journal of Sound and Vibration, 137, 403-418.
CHANG, Y. C., YEH, L. J., CHIU, M. C. (2004), GA optimization on constrained venting system with single-chamber mufflers, Journal of the Acoustical Society of R.O.C., 10, 1-13.
CHANG, Y. C., YEH, L. J., CHIU, M. C. (2004), Optimization of absorbers and mufflers on constrained multi-noises system by using genetic algorithm, The Far East Journal of Applied Mathematics, 14(3), 261-299.
CHIU, M. C. (2010), Shape optimization of multi-chamber mufflers with plug-inlet tube on a venting process by genetic algorithms, Applied Acoustics, 71, 495-505.
CHIU, M. C. (2010), Shape optimization of one-chamber Mufflers with reverse-flow ducts using a genetic algorithm, Journal of Marine Science and Technology, 18(1), 12-23.
CHIU, M. C., CHANG, Y. C. (2008), Numerical studies on venting system with multi-chamber perforated mufflers by GA optimization, Applied Acoustics, 69(11), 1017-1037.
DAVIS, D. D., STOKES, J. M., MOORE, D., STEVEN, L.(1954), Theoretical and experimental investigation of mufflers with comments on engine exhaust muffler design, NACA Report, 1192.
HARTIG, H. E., SWANSON, C. E. (1938), Transverse acoustic waves in rigid tubes, Physical Review, 54, 618-626.
HOLLAND, J. (1975), Adaptation in natural and artificial system, Ann Arbor, University of Michigan Press..
IGARASHI, J., ARAI, M. (1960), Fundamentals of acoustical silencers, part 3: Attenuation characteristic studies by electric simulator, Aeronaut Res. Inst. University of Tokyo, Report No.351, 17-31.
IGARASHI, J., TOYAMA, M. (1958), Fundamentals of acoustical silencers, part 1: Theory and experiment of acoustic low-pass filters, Aeronaut Res. Inst. University of Tokyo, Report No.339, 223-241.
IH, J. G. (1992), The reactive attenuation of rectangular plenum chambers, Journal of Sound and Vibration, 157, 93-122.
IH, J.G., LEE, B.H. (1985), Analysis of higher-order mode effects in the circular expansion chamber with mean flow, Journal of the Acoustical Society of America 77, 1377-1388.
IH, J.G., LEE, B.H. (1987), Theoretical prediction of the transmission loss of circular reversing chamber mufflers, Journal of Sound and Vibration 112,261-272.
JAYARAMAN, K., YAM, K. (1981), Decoupling approach to modeling perforated tube muffler components, Journal of the Acoustical Society of America, 69(2), 390-396.
JONG, D. (1975), An analysis of the behavior of a class of genetic adaptive Systems, Doctoral Dissertation, Department of Computer and Communication Sciences, Ann Arbor, University of Michigan, USA.
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, 14-19.
MIWA, T., IGARASHI, J. (1959), Fundamentals of acoustical silencers, part 2: Determination of four terminal constants of acoustical element, Aeronaut Res. Inst. University of Tokyo, Report No.344, 67-85.
MUNJAL, M. L. (1957), Velocity ratio-cum-transfer matrix method for the evaluation of a muffler with mean flow, Journal of the Acoustical Society of America, 39, 105-119, 1957.
MUNJAL, M. L. (1987), A simple numerical method for three-dimensional analysis of simple expansion chamber mufflers of rectangular as well as circular cross-section with a stationary medium, Journal of Sound and Vibration, 116, 71-88.
SEYBERT, A. F., CHENG, C. Y. R. (1987), Application of the boundary element method to acoustic cavity response and muffler analysis, Transactions of the American Society of Mechanical Engineers, Journal of Vibration, Stress, and Reliability in Design, 109, 15-21.
STRUT, J. W. (LORD RAYLEIGH) (1945), The theory of sound, Dover, New York.
SULLIVAN, J. W., CROCKER, M. J. (1978), Analysis of concentric-tube resonators having unpartitioned of cavities, Journal of the Acoustical Society of America, 64(1), 207-215.
SULLIVAN, J. W. (1979), A method for modeling perforated tube muffler components. I. Theory, Journal of the Acoustical Society of America, 66(3), 772-778, Sept., 1979.
YOUNG, C. I., CROCKER, M. J. (1975), Prediction of transmission loss in mufflers by the finite-element method, Journal of the Acoustical Society of America, 57, 144-148.