Investigation of the efficiency of various reactive mufflers by noise reduction and transmission loss analyses

Document Type : Invited by Davoud Younesian


1 Ph.D. Candidate, Faculty of Mechanical Engineering, K.N. Toosi University of Technology

2 Professor, Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran

3 Professor, Faculty of Mechanical Engineering, K.N. Toosi University of Technology

4 Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran.


Transmission loss and noise reduction of reactive mufflers are determined by linear acoustic theory and unsteady flow field study, respectively. The effects of extending the inlet tube of the muffler, adding holes to the extension, and the number of holes on both transmission loss and noise reduction are investigated. In noise reduction analysis, the Navier-Stokes equations and k-ε model are used to study the unsteady turbulent flow. Helmholtz equation is solved for transmission loss analysis. The present study is validated with experimental data. Numerical results show a rise in noise reduction by extending the inlet tube of the muffler and increasing its length. Moreover, the extended mufflers cause more transmission loss and broadband behavior at some frequencies due to the resonances. According to the results, different points of view in the investigation of acoustic attenuation performance of mufflers can be helpful to understand more and better about the effect of geometrical parameters.


  • Linear acoustic theory and unsteady flow field are considered.
  • The Navier-Stokes equations, k- ε model, and Helmholtz equation are used.
  • Effects of geometrical parameters on acoustic attenuation are studied.
  • Different views are found necessary to study acoustic attenuation performance.


Main Subjects

[1] M.L. Munjal, Acoustics of ducts and mufflers with application to exhaust and ventilation system design, John Wiley & Sons, 1987.
[2] S. Kore, A. Aman, E. Direbsa, Performance evaluation of a reactive muffler using CFD, Journal of EEA 28 (2011) 83-89.
[3] R.F. Barron, Industrial noise control and acoustics, Marcel Dekker, Inc., New York, (2003).
[4] B.C. Nakra, W.K. Sa'id, A. Nassir, Investigations on mufflers for internal combustion engines, Applied acoustics, 14 (1981) 135-145.
[5] A. Selamet, Z.L. Ji, Acoustic attenuation performance of circular expansion chambers with extended inlet/outlet, Journal of Sound and Vibration, 223 (1999) 197-212.
[6] I. Lee, K. Jeon, J. Park, The effect of leakage on the acoustic performance of reactive silencers, Applied Acoustics, 74 (2013) 479-484.
[7] S. Banerjee, A.M. Jacobi, Transmission loss analysis of single-inlet/double-outlet (SIDO) and double-inlet/single-outlet (DISO) circular chamber mufflers by using Green’s function method, Applied Acoustics, 74 (2013) 1499-1510.
[8] M.L. Munjal, K.N. Rao, A.D. Sahasrabudhe, Aeroacoustic analysis of perforated muffler components, Journal of Sound and Vibration, 114 (1987) 173-188.
[9] E.L.-R. Abd, A. I., A.S. Sabry, A. Mobarak, Non-linear simulation of single pass perforated tube silencers based on the method of characteristics, Journal of sound and vibration, 278 (2004) 63-81.
[10] S.N. Gerges, R. Jordan, F.A. Thieme, J.L. Bento Coelho, J.P. Arenas, Muffler modeling by transfer matrix method and experimental verification, Journal of the Brazilian Society of Mechanical Sciences and Engineering, 27 (2005) 132-140.
[11] D.D. Zhu, Z.L. Ji, Transmission loss prediction of reactive silencers using 3-D time-domain CFD approach and plane wave decomposition technique, Applied Acoustics, 112 (2016) 25-31.
 [12] D.P. Jena, S.N. Panigrahi, Numerically estimating acoustic transmission loss of a reactive muffler with and without mean flow, Measurement, 109 (2017) 168-186.
 [13] S.E. Razavi, M. Azhadarzadeh, B. Harsini, Noise Reduction in Expansion Chambers of IC Engines by Unsteady Flow Analysis, Iranian Journal of Mechanical Engineering (English) 8:, (2007) 504-515.
[14] R. Barbieri, N. Barbieri, The technique of active/inactive finite elements for the analysis and optimization of acoustical chambers, Applied Acoustics, 73 (2012) 184-189.
[15] J.W. Lee, Optimal topology of reactive muffler achieving target transmission loss values: Design and experiment, Applied acoustics, 88 (2015) 104-113.
[16] M. Ranjbar, M. Kemani, A comparative study on design optimization of mufflers by genetic algorithm and random search method, Journal of Robotic and Mechatronic Systems, 1 (2016) 7-12.
[17] s. Chao, H. Liang, Comparison of various algorithms for improving acoustic attenuation performance and flow characteristic of reactive mufflers, Applied Acoustics, 116 (2017) 291-296.
[18] F.M. Azevedo, M.S. Moura, W.M. Vicente, R. Picelli, R. Pavanello, Topology optimization of reactive acoustic mufflers using a bi-directional evolutionary optimization method, Struct Multidisc Optim, (2018) 1-14.
[19] M.C. Chiu, Y.C. Chang, H.C. Cheng, T.Y. Lin, Optimization of multiple-curve-tube mufflers using neural networks, the boundary element method and GA method, Journal of Statistics and Management Systems, 21 (2018) 787-806.
[20] F.J. Fahy, Foundations of engineering acoustics, Academic Press, Northern Illinois University, 2001.
[21] D.C. Wilcox, Turbulence modeling for CFD, DCW industries La Canada, CA, 1993.
[22] W.H. Press, B.P. Flannery, S.A. Teukolsky, W.T. Vetterling, Numerical recipes, Cambridge university press Cambridge, 1989.
[23] A. Selamet, P.M. Radavich, The effect of length on the acoustic attenuation performance of concentric expansion chambers: an analytical, computational and experimental investigation, Journal of Sound and Vibration, 201 (1997) 407-426.
[24] C.N. Wang, A numerical scheme for the analysis of perforated intruding tube muffler components, Applied Acoustics, 44 (1995) 275-286.
[25] A. Selamet, N. Dickey, J. Novak, The Herschel–Quincke tube: a theoretical, computational, and experimental investigation, The Journal of the Acoustical Society of America, 96 (1994) 3177-3185.
[26] C.N. Wang, C.C. Tse, Y.N. Chen, Analysis of three dimensional muffler with boundary element method, Applied acoustics, 40 (1993) 91-106.