Transmission Loss analysis of a simple expansion chamber muffler with extended inlet and outlet combined with inhomogeneous micro-perforated panel (iMPP)

Rafique, Faisal; Wu, Jiu Hui; Liu, Chong Rui; Ma, Fuyin

doi:10.1016/j.apacoust.2022.108808

Cited by 14 publications

(13 citation statements)

References 24 publications

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“…The arrangment ensures that there is a significant difference between the resonance frequencies of two THRs in the same cross-section, thus eliminating the mutual coupling between the two THRs. The specific geometric parameters of the units are shown in table 5.…”

Section: Reactive Muffler For Low Frequency Broadbandmentioning

confidence: 99%

“…As the most common component of mufflers, porous sound absorbing materials (PSAM) can achieve efficient noise reduction in the middle and high-frequency range, as they can fully convert the sound energy entering the micropores into thermal energy for energy consumption [2,3]. Expansion cavity muffler, as a familiar silencer structure, introduces a mismatch in acoustic impedance due to variable cross-sectional area, thereby causing efficient reflection of sound wave for sound insulation [4,5]. However, these traditional mufflers cannot give satisfactory results in the low-frequency band without large volumes and bulky materials.…”

Section: Introductionmentioning

confidence: 99%

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Design and demonstration of composite mufflers based on dissipative and reactive units

Shi,

Yang,

Mei

et al. 2023

Eng. Res. Express

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We have proposed and validated a design of a composite muffler. By a combination of dissipative and reactive units with different operating mechanisms, the advantages of both structures are utilized to achieve high transmission loss (TL) from low to high frequency in the ventilation duct system. A dissipative muffler composed of porous sound absorbing materials (PSAM) is chosen for noise attenuation above 1000 Hz, and a reactive muffler composed of Helmholtz resonators is used to reduce the noise below 1000 Hz. The combination of the two can achieve a TL above 20 dB in the broadband range of 244-1600 Hz and up to 30 dB in the vast majority of the frequency band, demonstrating excellent noise reduction effect. The proposed composite muffler has great advantages in broadband noise reduction for ventilation systems.

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Section: Reactive Muffler For Low Frequency Broadbandmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design and demonstration of composite mufflers based on dissipative and reactive units

Shi,

Yang,

Mei

et al. 2023

Eng. Res. Express

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show abstract

“…Specifically, one research study with in homogeneous microperforated panels (iMPPs) inside an extended inlet and outlet muffler concluded that depth of air cavity has effect on Transmission Loss. The results were validated by comparing simulations and experimental data (1) . Similar study carried out on muffler with tapered section for side outlet.…”

Section: Introductionmentioning

confidence: 99%

Effect of Variations in Diameter of Extended Inlet on Transmission Loss of Single Expansion Chamber Reactive Muffler with Extended Inlet

Suratwala¹,

Kulkarni²

2023

IJST

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Objectives: Muffler with extended inlet has an additional dimension of variable compared to normal mufflers, that is the diameter. Understanding the effect of change in this diameter value affects Transmission Loss. Muffler used for experimentation is a reactive muffler, which cancels the noise waves using reflection phenomenon. Comparison of Computer Aided Engineering (CAE) in experiments to signify the technology advancement. Methods: MATLAB program is created for running the data and analytical solution. Finite element analysis with COMSOL Multiphysics using 3D model of muffler and computer aided engineering is done considering boundary conditions. The real experiment is carried out to evaluate confidence in simulated results where two load method is applied. Findings: Experimental setup results are showing results close to Numerical analysis. Analysis of the study suggest increase in diameter leads to rise in transmission loss. The experimental results of selected dimensions setup also prove same. Various geometric variation in muffler have effect of 10 to 30% on TL, while changing diameter from 10 to 20 mm of extended inlet raise the peak of TL to almost double and increase the average TL by 28%. Novelty: A diameter variation in extended inlet is an empty space in literature till now. This research combines analytical and experimental setups and comparison of results leads to a strong conclusion toward better muffler design.

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“…The muffler is inevitable part of automobiles. Reactive muffler is one of the passive noise control devices used to control unavoidable noise; using destructive interference as a principle (1) . Wherever there is either sudden contraction or sudden expansion, the phase of the reflected wave changes causing destructive interference (2) .…”

Section: Introductionmentioning

confidence: 99%

Role of End-Correction in Enhancing Transmission Loss Estimates in Case of Extended Inlet-Outlet Expansion Chamber Mufflers Using Simulation

Kale¹,

Surve²

2023

IJST

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Objectives: Measuring transmission loss of a muffler in a lab setting ideally requires an anechoic termination at one end, and hence turns out to be tedious. Simulation gives the freedom of changing the geometry of object without destructing it. Methods: Lab grade expansion chamber mufflers are remodelled into extended tube expansion chamber mufflers using simulation. Furthermore, applying end correction helps in optimizing their geometry. The same technique is extended to concentric tube resonators by varying the porosity handle. Findings: With simulation, number of parameters can be changed multiple times by keeping other handles constant. Novelty: Lab grade mufflers are to be modified with non-destructive method for getting improved performance. Hence, to check and optimise the parameters, the present dimensions of lab grade mufflers are kept constant and the results are checked using simulation technique.

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Transmission Loss analysis of a simple expansion chamber muffler with extended inlet and outlet combined with inhomogeneous micro-perforated panel (iMPP)

Cited by 14 publications

References 24 publications

Design and demonstration of composite mufflers based on dissipative and reactive units

Design and demonstration of composite mufflers based on dissipative and reactive units

Effect of Variations in Diameter of Extended Inlet on Transmission Loss of Single Expansion Chamber Reactive Muffler with Extended Inlet

Role of End-Correction in Enhancing Transmission Loss Estimates in Case of Extended Inlet-Outlet Expansion Chamber Mufflers Using Simulation

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