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Technical Briefs

Optimal Design of Multichamber Mufflers Hybridized With Perforated Intruding Inlets and Resonating Tubes Using Simulated Annealing

[+] Author and Article Information
Min-Chie Chiu1

Department of Automatic Control Engineering, Chungchou Institute of Technology 6, Lane 2, Sec.3, Shanchiao Road, Yuanlin, Changhua, Taiwan 51003, R.O.C.minchie.chiu@msa.hinet.net

1

Corresponding author.

J. Vib. Acoust 132(5), 054503 (Aug 26, 2010) (9 pages) doi:10.1115/1.4001514 History: Received November 01, 2009; Revised March 16, 2010; Published August 26, 2010; Online August 26, 2010

Recently, research on new techniques for single-chamber mufflers equipped with perforated resonating tubes has been addressed. However, the acoustical performance of mufflers having a narrow-band sound transmission loss (STL) is insufficient in reducing a broadband venting noise. To improve the acoustical efficiency, a hybrid muffler with chambers composed of perforated intruding inlets is presented. Here, we will not only analyze the STL of three kinds of mufflers (A: a one-chamber muffler hybridized with a perforated resonating tube; B: a two-chamber muffler hybridized with a perforated intruding tube and a resonating tube; and C: a three-chamber muffler hybridized with two perforated intruding tubes and a resonating tube), but also optimize the best design shape within a space-constrained situation. In this paper, both the numerical decoupling technique and simulated annealing (SA) for solving the coupled acoustical problem of perforated tubes are used. A numerical case for eliminating a broadband air compressor noise is also introduced. To verify the reliability of SA optimization, optimal noise abatements for the pure tones (400 Hz and 800 Hz) are exemplified. Before the SA operation can be carried out, the accuracy of the mathematical model is checked using the experimental data. Results indicate that the maximal STL is precisely located at the desired target tones. The optimal result of case studies for eliminating broadband noise also reveals that the overall noise reduction with respect to the mufflers can be reduced from 131.6 dB(A) to 102.1 dB(A), 89.5 dB(A), and 82.1 dB(A). As can be seen, the acoustical performance will increase when the diameters (at the inlet tubes as well as perforated holes) decrease. Moreover, it is obvious that the acoustical performance will be improved when the chambers equipped with perforated intruding inlets are increased. Consequently, a successful approach used for the optimal design of the multichamber mufflers equipped with perforated intruding tubes and a resonating tube within a space-constrained condition has been demonstrated.

Copyright © 2010 by American Society of Mechanical Engineers
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Figures

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Figure 1

An air compressor within a constrained room

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Figure 2

The outlines of the mufflers (A: a one-chamber muffler hybridized with a perforated resonating tube; B: a two-chamber muffler hybridized with a perforated intruding inlet tube and a resonating tube; and C: a three-chamber muffler hybridized with two perforated intruding inlet tubes and a resonating tube)

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Figure 3

The recognition of the acoustical elements for the mufflers (A: a one-chamber muffler hybridized with a perforated resonating tube; B: a two-chamber muffler hybridized with a perforated intruding inlet tube and a resonating tube; and C: a three-chamber muffler hybridized with two perforated intruding inlet tubes and a resonating tube)

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Figure 4

The related acoustic pressure p and acoustic particle velocity u within the mufflers (A: a one-chamber muffler hybridized with a perforated resonating tube; B: a two-chamber muffler hybridized with a perforated intruding inlet tube and a resonating tube; and C: a three-chamber muffler hybridized with two perforated intruding inlet tubes and a resonating tube)

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Figure 5

Performance of a single-chamber perforated muffler without the mean flow (D1=0.058 m, Do=0.0762 m, Lc=0.0667 m, t=0.0081 m, dh=0.00249 m, η=0.037). Experimental data are from Ref. 1.

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Figure 6

Performance of a one-chamber muffler equipped with an perforated intruding inlet tube (D1=0.018 m, D2=0.018 m, Do=0.118 m, L4=0.08, L2=0.0, LC1=0.08, L1=L5=0.04, t1=0.001 m, dh1=0.003 m, η1=0.03375, M1=0.0). Experimental data are from Ref. 12.

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Figure 7

SA algorithm from a physical viewpoint

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Figure 8

The flow diagram of the SA optimization

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Figure 9

The STL with respect to frequencies at various kk (muffler B; iter=1000; targeted tone: 400 Hz)

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Figure 10

The STL with respect to frequencies at various iter (muffler B; kk=0.99; targeted tone: 400 Hz)

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Figure 11

The STL with respect to frequencies at various mufflers (targeted tone: 400 Hz)

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Figure 12

The STL with respect to frequencies at various mufflers (targeted tone: 800 Hz)

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Figure 13

The SWL with respect to frequencies at various mufflers (broadband noise)

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Figure 14

The optimal STL with respect to frequencies at various targeted tones and broadband noise (muffler A)

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Figure 15

The optimal STL with respect to frequencies at various targeted tones and broadband noise (muffler B)

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Figure 16

The optimal STL with respect to frequencies at various targeted tones and broadband noise (muffler C)

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