A New Type of Muffler Based on Microperforated Tubes

Allam, Sabry; Åbom, Mats

doi:10.1115/1.4002956

Cited by 145 publications

(70 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is reported in the literature that a can be taken as either 2 or 4. 5 Our results show that a value can be out of this interval depending on the Shear number. Moreover, with increasing Sh number, we observe an asymptotic approach in end-correction coefficients.…”

Section: Discussionmentioning

confidence: 90%

“…Especially, the coefficient for the resistive end-correction varies between 2 and 4 in the literature and this has been associated with edge geometry by Allam and Å bom. 5 On the other hand, the theoretical limit value for the reactive end-correction coefficient is reasonably accurate for most applications.…”

Section: Introductionmentioning

confidence: 99%

“…1, 5,6 Second, although slit shaped MPPs appear to be quite promising, 5 here, we concentrate on circular perforation geometries so that they can be represented in 2D axisymmetrical geometry in numerical model. Finally, we carry out measurements with a single perforation diameter for all samples.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The influence of edge geometry on end-correction coefficients in micro perforated plates

Temiz

Arteaga

Efraimsson

et al. 2015

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

Global expressions are proposed for end-correction coefficients in micro perforated plates (MPPs) using non-dimensional parameters. MPPs are sound absorbers with small perforation diameters such that the Stokes boundary layers fill up almost the entire perforation. Sound absorption does not only occur within the perforation, but also takes place just outside of it. The latter contribution plus the outside inertia effect on the transfer impedance of the MPP are referred to as end-corrections. In order to determine them, an analytical solution employing the very thin Stokes layer assumption has been derived. However, this assumption requires empirical coefficients in the end-corrections for accurate results. To explore the effects of various parameters a numerical model is used. This model is verified with open-end reflection coefficient measurements. The most prominent result from this study is that compared to plate thickness, the ratio of perforation diameter to Stokes layer thickness (Shear number) and edge geometry affect the end-correction coefficients more significantly. The effect of plate thickness can be neglected for practical purposes, therefore, expressions for the end-corrections in terms of Shear number and edge geometry are provided. The relative error of these expressions is <3% compared to the numerical results.

show abstract

Section: Discussionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The influence of edge geometry on end-correction coefficients in micro perforated plates

Temiz

Arteaga

Efraimsson

et al. 2015

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

show abstract

“…For dissipative silencers, porous materials are commonly used for mitigating mid-tohigh-frequency noise [7,8], but have the disadvantages of being flammable, bulky, non-fibreless, and non-durable. More recently, micro-perforated panel (MPP) silencers were proposed to tackle these problems, and they provide good silencing performance comparable to porous materials while having less engineering constraints [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…Reactive and dissipative silencers with a simple expansion chamber have been extensively investigated [1][2][3][4][5][6][7][8][9][10]. For reactive silencers, Selamet and Ji [1] studied the effect of adding inlet/outlet extensions on the suppression of the pass-bands of the dome-like transmission loss (TL) pattern.…”

Section: Introductionmentioning

confidence: 99%

Sub-chamber optimization for silencer design

Tong

2015

Journal of Sound and Vibration

View full text Add to dashboard Cite

Additively Manufactured Deformation‐Recoverable and Broadband Sound‐Absorbing Microlattice Inspired by the Concept of Traditional Perforated Panels

Zhai

2021

Advanced Materials

View full text Add to dashboard Cite

unattended to, prolonged exposure leads to acute and chronic health hazards and complications such as hearing loss, cardiovascular diseases, cognitive impairment, etc. [1] Sound absorbing materials hence find widespread adoption in a diverse range of applications. For reference, the market value for acoustic materials has been constantly increasing and it is projected to be 16 billion U.S. dollars in 2025, nearly doubling that in 2015. [2] Traditional and commercial sound absorbers in the market have always been focused on foams, fibrous materials, fabric, and perforated panels. [3] However, limitations of the traditional absorbers exist, for instance, such as non-optimal designs, lack of structural rigidity, and health hazards (from synthetic fibers), etc. As such, increasing research efforts have been placed on the investigations of new materials and new meta-structures for novel and better performing sound absorbers. [4] Several examples of new materials investigated as sound absorbers include graphene-based foams, [5] shape memory foams, [6] window foams, [7] and aerogels. [8] However, material-based absorbers compare generally pale in performance to structure-based ones under similar specifications (e.g., thickness, target frequency). Further, such materials also usually lack the rigidity of structures and some may also pose potential health hazards. In turn, structure-based absorbers are more robust and notable successes have been achieved with superior absorption capabilities and broadened absorption range shown. Examples of novel absorbing structures investigated include the Fabry-Perot channel assembly, [9] planar coiled tubes, [10] perforated composite resonators, [11] membrane structures, [12] and shrinking duct structures, [13] etc. Despite the success, the mentioned examples nonetheless are still limited to a structural level-they lack the design flexibilities for an overall system or product.As such, it would be of high research interests to design absorbers based on the principles of structural designs, but yet to down-scale them to a size domain in the range of materials. The advent of additive manufacturing (AM) in the recent years has brought about such possibilities. Apart from being an effective rapid-prototyping tool and a viable manufacturing Noise pollution is a highly detrimental daily health hazard. Sound absorbers, such as the traditionally used perforated panels, find widespread applications. Nonetheless, modern product designs call for material novelties with enhanced performance and multifunctionality. The advent of additive manufacturing has brought about the possibilities of functional materials design to be based on structures rather than chemistry. With this in mind, herein, the traditional concept of perforated panels is revisited and is incorporated with additive manufacturing for the development of a novel microlattice-based sound absorber with additional impact resistance multifunctionality. The structurally optimized microlattice presents excellent broadband absorption with a...

show abstract

A New Type of Muffler Based on Microperforated Tubes

Cited by 145 publications

References 12 publications

The influence of edge geometry on end-correction coefficients in micro perforated plates

The influence of edge geometry on end-correction coefficients in micro perforated plates

Sub-chamber optimization for silencer design

Additively Manufactured Deformation‐Recoverable and Broadband Sound‐Absorbing Microlattice Inspired by the Concept of Traditional Perforated Panels

Contact Info

Product

Resources

About