Spiral hole dual-porosity sound absorbing device and application thereof

A sound-absorbing device and dual-porosity technology, which is applied to sound-producing instruments, instruments, etc., can solve the problems that the effective sound-absorbing frequency bandwidth is not as good as that of porous materials, the thickness of the back cavity is increased, and the low-frequency sound-absorbing effect is poor, so as to achieve a good application prospect. , the effect of promoting diffusion and increasing tortuosity

Pending Publication Date: 2019-04-26
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] (1) For porous materials mainly composed of porous foam and porous fiber, the sound absorption coefficient increases with the increase of frequency, which is suitable for high-frequency sound absorption and has a wide effective sound absorption frequency band. The disadvantage is that the low-frequency sound absorption effect is poor;
[0004] (2) A micro-perforated plate with a back cavity, which can have resonance sound absorption peaks at lower frequencies, is suitable for middle and low frequency sound absorption. The larger the thickness of the back cavity, the better the low-frequency sound absorption effect, but the back cavity The increase in thickness also takes up more space, and some scenes with limited space limit its use. At the same time, its effective sound absorption frequency band width is not as good as that of porous materials.

Method used

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  • Spiral hole dual-porosity sound absorbing device and application thereof
  • Spiral hole dual-porosity sound absorbing device and application thereof
  • Spiral hole dual-porosity sound absorbing device and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] see figure 1 Cells in and figure 2 In the sound absorption curve of the unit cell, a spiral hole 2 is set in a porous material substrate 1 with a total height H of 50mm and a diameter D of 35mm. The porosity of the substrate porous material is 90%, and the flow resistance rate is 489336N·s / m 2 , the viscous characteristic length is 19.7 μm, the thermal characteristic length is 36 μm, and the tortuosity is 1.05; the helical hole 2 is opened with the helix 3 as the guide, and the helical hole 2 is circular in the direction perpendicular to the helix 3, and the diameter of the circle is The aperture d of the spiral hole is 10mm, the spiral radius l of the spiral 3 is 15mm for this spiral diameter, the pitch p of the spiral 3 is 15mm, and the opening ratio of the spiral hole 2 (the total volume of the opening accounts for the base The total volume) is 26.5%; the lower end of the sound-absorbing device is placed on a rigid backing to simulate the situation where the desi...

Embodiment 2

[0056] see Figure 3 to Figure 7 , with the material parameters and structural parameters in Example 1 as default values, using the single variable method, the influence of different substrate porous materials and structural dimensions on the sound absorption coefficient of the invented spiral opening double-porosity sound-absorbing device is given; image 3 The parameters of the three porous materials are: porous material MAT1, the porosity is 90%, and the flow resistance is 489336N·s / m 2 , the viscous characteristic length is 19.7μm, the thermal characteristic length is 36μm, and the tortuosity is 1.05; the porous material MAT2 has a porosity of 99% and a flow resistance of 200000N·s / m 2 , the viscous characteristic length is 17.48μm, the thermal characteristic length is 34.96μm, and the tortuosity is 1; the porous material MAT3 has a porosity of 94% and a flow resistance of 135000N·s / m 2 , the viscous characteristic length is 49 μm, the thermal characteristic length is 166...

Embodiment 3

[0063] see Figure 8 The schematic diagram of the cells in , in the porous material substrate 1, there are intertwined and connected double helical holes, the height of the substrate material is 50mm, and the diameter is 50mm; the porosity of the porous material of the substrate is 90%, and the flow resistance rate is 489336N·s / m 2 , the viscous characteristic length is 19.7 μm, the thermal characteristic length is 36 μm, and the tortuosity is 1.05. The two helical holes 2 provided are the same, the apertures are 10mm, the helical diameter of the corresponding helix is ​​30mm, and the pitch is 30mm, and the two helical holes are connected to each other by three connected straight holes 4 with a diameter of 8mm. Connected to further increase the contact area between the opened holes and the porous material, at this time the porosity is 30%. The sound absorption coefficient of embodiment 2 of the present invention sees Figure 9 . Compared with porous material boards with the...

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Abstract

The invention discloses a spiral hole dual-porosity sound absorbing device and application thereof. The device is realized by forming a spiral hole in a substrate of a porous material, and the sinuosity of wound waves entering the porous material is greatly improved by a spiral channel. The sound waves first enter the spiral hole at a low frequency band and then enter micro pores of the porous material via the spiral hole. By utilizing sound energy dissipation brought by strong coupling of the wound waves between the spiral hole formed in the porous material and the micro pores of the porous material, the low-frequency sound absorption property of the sound absorbing material in the invention is enhanced. Moreover, by combining the consistently good high-frequency sound absorption propertyof the porous material, the spiral hole dual-porosity sound absorbing device disclosed by the invention can reach a sound absorption peak value at an ultralow frequency under the condition that the thickness is small, and also has a certain medium-high frequency sound absorbing ability. The device disclosed by the invention is simple in structure and practical and has excellent and wide application prospects.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a sound-absorbing device with spiral openings and double porosity and its application. Background technique [0002] Existing sound-absorbing materials are mainly used for sound absorption and noise reduction, and are mainly used in concert halls, museums, libraries, anechoic rooms, both sides of roads, and inner walls of vehicles. Traditional sound-absorbing materials are mainly divided into two categories: [0003] (1) For porous materials mainly composed of porous foam and porous fiber, the sound absorption coefficient increases with the increase of frequency, which is suitable for high-frequency sound absorption and has a wide effective sound absorption frequency band. The disadvantage is that the low-frequency sound absorption effect is poor; [0004] (2) A micro-perforated plate with a back cavity, which can have resonance sound absorption peaks at l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10K11/16G10K11/162
CPCG10K11/16G10K11/162
Inventor 辛锋先刘学伟
Owner XI AN JIAOTONG UNIV
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