Aeroacoustic analysis of perforated muffler components

Munjal, ML; Rao, K. Balaji; Sahasrabudhe, Anil

doi:10.1016/s0022-460x(87)80146-3

Cited by 99 publications

(37 citation statements)

References 6 publications

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“…The present work utilizes the TMM suggested by Munjal et al [5]. This method is well suited for the standard plug flow muffler as defined in Figure 1.…”

Section: Transfer Matrix Methodsmentioning

confidence: 99%

“…This is a non-physical situation as the change in cross-sectional area from the inner to the outer section entails a change in mean flow velocity, except for the zero mean flow case. Munjal et al addressed this limitation and produced an analytical decoupling method which accounted for the difference in mean flow velocity in the interior tube and exterior annulus [5]. This was successfully applied to more complex muffler geometries such as the three-duct perforated muffler.…”

Section: Introductionmentioning

confidence: 99%

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Modelling and Optimization of Plug Flow Mufflers in Emission Control Systems

Puthuparampil

Pong²,

Sullivan

2017

SAE Technical Paper Series

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Always cite the published version, so the author(s) will receive recognition through services that track citation counts, e.g. Scopus. If you need to cite the page number of the author manuscript from TSpace because you cannot access the published version, then cite the TSpace version in addition to the published version using the permanent URI (handle) found on the record page.This article was made openly accessible by U of T Faculty. Please tell us how this access benefits you. Your story matters. AbstractLarge-scale emergency or off-grid power generation is typically achieved through diesel or natural gas generators. To meet governmental emission requirements, emission control systems (ECS) are required. In operation, effective control over the generator's acoustic emission is also necessary, and can be accomplished within the ECS system. Plug flow mufflers are commonly used, as they provide a sufficient level of noise attenuation in a compact structure. The key design parameter is the transmission loss of the muffler, as this dictates the level of attenuation at a given frequency. This work implements an analytically decoupled solution, using multiple perforate impedance models, through the transfer matrix method (TMM) to predict the transmission loss based on the muffler geometry. An equivalent finite element model is implemented for numerical simulation. The analytical results and numerical results are then evaluated against experimental data from literature. The transmission loss required in each application of the ECS system will vary depending on the noise profile of the generator in question; therefore, it is necessary to have an effective method of redesigning the muffler to meet the design requirements. Prior work on TMM-based muffler shape optimization utilized complex algorithms such as neural networks and simulated annealing. The present study simplifies the process by using the bounded, limited-memory implementation of the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm in a multi-start framework for shape optimization to achieve the desired transmission loss. By constraining the multi-start method with appropriate design limits, the algorithm is initialized at multiple random points within the design space, ensuring that the solution approaches the global optimum when using a sufficiently large number of initializations.

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“…The present work utilizes the TMM suggested by Munjal et al [5]. This method is well suited for the standard plug flow muffler as defined in Figure 1.…”

Section: Transfer Matrix Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modelling and Optimization of Plug Flow Mufflers in Emission Control Systems

Puthuparampil

Pong²,

Sullivan

2017

SAE Technical Paper Series

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“…In the past decade, intent on increasing acoustical performance, the assessment of a new acoustical element was introduced and discussed by Sullivan and Crocker in 1978 [1]. Based on the couple equations derived by Sullivan and Crocker, a series of theories and numerical techniques in decoupling the acoustical problems were proposed [2]- [5].The shape optimization of a one-chamber muffler equipped with a perforated tube and plug/non-plug tubes has been discussed with neural network. Bai et al [6]studies exhaust muffler optimization design based on the neural network, it put artificial neural network into the exhaust muffler design.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Performance of Exhaust Muffler Based Genetic Algorithms and Artificial Neural Network

Wang

2013

TELKOMNIKA

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“…On the basis of coupled differential equations, a series of theoretical and numerical techniques in decoupling the acoustical problems have been proposed (Sullivan, 1979a(Sullivan, , 1979bThawani, Jayaraman, 1983;Rao, Munjal, 1984;Jayaraman, Yam, 1981;Munjal et al, 1987). Peat (1988) publicized a successful numerical decoupling method by finding the eigen value in transfer matrices.…”

Section: Introductionmentioning

confidence: 99%

Optimization Design of Hybrid Mufflers on Broadband Frequencies Using the Genetic Algorithm

Chiu¹

2011

Archives of Acoustics

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Recently, there has been research on high frequency dissipative mufflers. However, research on shape optimization of hybrid mufflers that reduce broadband noise within a constrained space is sparse. In this paper, a hybrid muffler composed of a dissipative muffler and a reactive muffler within a constrained space is assessed. Using the eigenvalues and eigenfunctions, a coupling wave equation for the perforated dissipative chamber is simplified into a four-pole matrix form. To efficiently find the optimal shape within a constrained space, a four-pole matrix system used to evaluate the acoustical performance of the sound transmission loss (STL) is evaluated using a genetic algorithm (GA).A numerical case for eliminating a broadband venting noise is also introduced. To verify the reliability of a GA optimization, optimal noise abatements for two pure tones (500 Hz and 800 Hz) are exemplified. Before the GA operation can be carried out, the accuracy of the mathematical models has been checked using experimental data. Results indicate that the maximal STL is precisely located at the desired target tone. The optimal result of case studies for eliminating broadband noise also reveals that the overall sound power level (SWL) of the hybrid muffler can be reduced from 138.9 dB(A) to 84.5 dB(A), which is superior to other mufflers (a one-chamber dissipative and a one-chamber reactive muffler). Consequently, a successful approach used for the optimal design of the hybrid mufflers within a constrained space has been demonstrated.

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Aeroacoustic analysis of perforated muffler components

Cited by 99 publications

References 6 publications

Modelling and Optimization of Plug Flow Mufflers in Emission Control Systems

Modelling and Optimization of Plug Flow Mufflers in Emission Control Systems

Acoustic Performance of Exhaust Muffler Based Genetic Algorithms and Artificial Neural Network

Optimization Design of Hybrid Mufflers on Broadband Frequencies Using the Genetic Algorithm

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