A ventilation and sound insulation array structure and design method thereof

Abstract

The present invention discloses a ventilation and sound insulation array structure and a design method thereof. The ventilation and sound insulation array has M rows of sound insulation rows. The large interval between each two sound insulation rows can achieve high ventilation rate ventilation. Each row of sound insulation rows is composed of N sound insulation units connected in series. Each sound insulation unit includes two openings located on both sides. The openings are connected to the same cavity through two connecting throats of different widths. By designing the width of each connecting throat of the N sound insulation units and the width of the cavity, each sound insulation unit can be made to operate at a different frequency. The N sound insulation units with different operating frequencies work together to achieve wide-band sound insulation. At the same time, the superposition effect of the coupled operation of adjacent units can improve the structural sound insulation. The ventilation and sound insulation array structure can have a good isolation and suppression effect on continuous noise in the range of 800 to 2000 Hz. At the same time, the operating frequency can be easily adjusted by changing the width of the sound insulation unit.

Description

Technical Field

[0001] The present invention relates to the technical field of noise control, and in particular to a ventilation and sound insulation array structure and a design method thereof. Background Art

[0002] With the development of industrial technology, industrial noise emitted by large machinery and vehicles is unavoidable and can seriously damage the hearing of factory workers. Traditional porous sound-absorbing materials have limited sound insulation effect on low-frequency noise. At the same time, in special scenarios such as exhaust ducts, the duct structure may need to be ventilated while reducing noise, which poses a huge challenge to traditional sound-absorbing materials. As research on acoustic metamaterials deepens, many metamaterials with excellent low-frequency sound absorption and insulation properties have been proposed. These metamaterials can effectively isolate low-frequency noise. However, even so, it is difficult to ensure efficient sound insulation across a wide frequency band while maintaining high ventilation performance. Summary of the Invention

[0003] The purpose of the present invention is to address the problems existing in the background technology and propose a ventilation and sound insulation array structure and its design method that can isolate broadband low-frequency noise and ensure ventilation performance. The structure can be used in scenes such as buildings that require ventilation and exhaust ducts used in industry.

[0004] The technical solution of the present invention is a ventilation sound insulation array structure, in which one of the sound-absorbing units has two openings on both sides, which are connected to the common cavity in the middle through the throat on both sides. The length and width of the basic unit are recorded as L, the wall thickness of all units is t, and the size of the openings on both sides (throat width) are recorded as LW respectively. a -t with LW b -t, height is recorded as H;

[0005] Furthermore, by measuring the frequency spectrum of the noise to be isolated, the frequency range of the noise to be isolated is determined;

[0006] Furthermore, through the acoustic-electrical analogy method, the throat is regarded as the sound sensor and the middle cavity is regarded as the sound volume. The formula for the operating frequency of the anechoic unit is obtained as follows:

[0007]

[0008] in By the lowest frequency, select the value of L, and by the operating frequency range, determine a series of W a With W b (A total of N groups, representing a total of N muffler units working at different frequencies). It should be noted that at low frequencies, the working frequency f should be more dense. Preferably, the W of the previous unit should be b With the next unit Wa The same value is used to ensure uniform coverage of the operating frequency;

[0009] Furthermore, the silencer units with designed size parameters are connected in series to form a silencer column;

[0010] Furthermore, M identical silencer columns are periodically arranged side by side at a distance D, ensuring that the openings on both sides of the silencer units in the silencer column are connected to the spaces (ventilation spaces) on both sides.

[0011] Compared with the prior art, the present invention has the following beneficial technical effects:

[0012] 1. The muffler unit of the present invention is composed of two throats and a common cavity. By fixing the total side length of the muffler unit and designing the thickness of the throats on both sides, the operating frequency of the current muffler unit can be quickly determined according to the theoretical formula, and the sound insulation frequency is highly adjustable;

[0013] 2. By connecting silencer units with different operating frequencies in series to form a silencer array, the operating bandwidth can be increased efficiently and simply;

[0014] 3. By placing the silencer columns at intervals, a larger interval can achieve a high ventilation rate. At the same time, the silencer columns on both sides work at the same time to ensure the sound insulation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0016] Figure 2 This is a top view of three noise reduction columns of the present invention;

[0017] Figure 3 This is a unit structure diagram of the tenth muffler unit 210 in the second row of the present invention.

[0018] Figure numerals: 1, first silencer row; 101-120, 1st to 20th silencer units on the first silencer row; 2, second silencer row; 201-220, 1st to 20th silencer units on the second silencer row; 2101, left throat pipe; 2102, right throat pipe; 2103, middle cavity; 3, third silencer row; 41, first ventilation interval; 42, second ventilation interval. DETAILED DESCRIPTION

[0019] Example 1

[0020] like Figure 1-2As shown, the ventilation sound insulation array structure in the embodiment of the present invention is composed of three rows of sound insulation rows (M=3), namely the first sound insulation row 1, the second sound insulation row 2, and the third sound insulation row 3. Their height H=20mm, and the distance between each two rows of sound insulation rows is D=80mm, forming two ventilation intervals, namely the first ventilation interval 41 and the second ventilation interval 42. In these two ventilation intervals, isolation between ventilation and sound propagation is achieved. The ventilation and sound propagation directions are as follows: Figure 2 In the direction of the arrow;

[0021] The shape and structure of each muffler row are exactly the same. For example, the second muffler row in the middle is composed of N=20 muffler units (201-220). The internal shape of each muffler unit is similar, but the size is different.

[0022] like Figure 3 As shown, the common features of the structures of the various silencer units are described in detail in conjunction with the tenth silencer unit 210. The total side length of the silencer unit is L = 25 mm, which is the overall dimension of all the silencer units. The wall thickness is t = 1.5 mm. The silencer unit includes two openings, which are oriented toward the ventilation gaps on both sides. Sound enters the silencer unit from the ventilation gaps. The two openings are connected to the left throat pipe 2101 and the right throat pipe 2102, respectively. The width dimensions of the throat pipes are LW a -t with LW b -t, two throats are connected to an intermediate cavity 2103, whose width is also affected by W a , W b With the fixed length constraint of L, the difference between each muffler unit is determined by W a With W b These two dimensions are provided. Specifically, in this embodiment, the two dimensions of the i-th (i=1, 2, ..., 20) muffler unit can be obtained by the following recursive relationship (Formula 1):

[0023]

[0024] Where, W1=18.25mm, k=0.018125, N=20. It should be noted that the recursive formula makes W a With W b Compared with the units with smaller size values, the size change between adjacent numbered units is smaller. This is a better implementation method. The purpose is to make the operating frequency as continuous and reliable as possible in the low frequency range. In addition, the W of the previous unit b With the W of the next unit a The same means that the width of the right throat of the previous unit is equal to the width of the left throat of the next unit. This is also to ensure that the operating frequencies of the two adjacent units are close to each other, so that the sound insulation frequency is continuous when working together;

[0025] Furthermore, by making an acoustic-electric analogy between the two throats and the middle cavity, the operating frequency of each muffler unit is derived based on the equivalent circuit model. The two throats are analogized to inductors (acoustic mass):

[0026]

[0027] The effective pipe length is: Opening area: S l =(LW l -t)H(l=a,b);

[0028] Consider the middle cavity as a capacitor:

[0029]

[0030] The cavity volume is: V0=(W a +W b -L)HL, sound speed: c0 = 343m / s, air density ρ0 = 1.21kg / m 3

[0031] The sound pressure at the left and right openings is recorded as p1 and p2 respectively, and the sound pressure inside the cavity is recorded as p. The circuit expression can be written as:

[0032]

[0033] When the sound pressure at these two locations is 0, it indicates that the muffler unit is in a local resonance state, which can effectively dissipate the sound energy in the cavity and achieve the muffler effect. Substituting this condition into formula (4), the unit sizes L and W can be derived. a 、W b The relationship between it and the operating frequency f is:

[0034]

[0035] In the formula According to formula (5), the operating frequency of each muffler unit can be determined, and then the operating frequency range of the muffler column or the entire ventilation sound insulation array can be determined, that is, the frequency range of sound that the array can effectively isolate.

[0036] In this embodiment, the dimensional parameters designed according to formula (1) can effectively isolate broadband noise from 800 Hz to 2000 Hz, with a bandwidth exceeding one octave. The sound insulation efficiency is expressed as a sound insulation greater than 18 decibels.

[0037] From the above embodiments, it can be found that the operating frequency can be simply adjusted by W of each unit. a 、W bFrom the main selection, the lowest operating frequency can be further reduced by increasing L. The ventilation and sound insulation array of the present invention is highly frequency-adjustable.

[0038] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A ventilation and sound insulation array structure, characterized in that: It includes M muffler columns; ventilation intervals are set between adjacent muffler columns; the muffler columns have the same structure, and the ventilation intervals between the muffler columns have the same spacing; The direction of the ventilation interval is the same as the ventilation direction; the sound propagation direction is along the longitudinal arrangement direction of the silencer rows, and the silencer rows are arranged periodically perpendicular to the sound propagation direction; Each silencer row includes N silencer units; throats are provided on both sides of the silencer unit, and a hollow cavity is provided in the middle; openings are provided on both sides of the silencer unit, and the throats are connected to the ventilation space through the openings; the throats on both sides of the silencer unit are connected to the cavity; the width of the throats on the left and right sides of the same silencer unit is different; the sum of the width of the throats on both sides and the width of the cavity is a fixed value; Different silencer units in the same silencer row have the same external dimensions, but different internal throat widths and cavity widths; the right throat width of the preceding unit is equal to the left throat width of the following unit; The width of the throats on both sides of the silencer unit and the size of the cavity determine the operating frequency of the silencer unit; different silencer units work in coupling to isolate broadband noise.

2. A ventilation and sound insulation array structure according to claim 1, characterized in that: The wall thickness of each silencer unit in the silencer column is the same; and all ventilation and sound insulation sections are rectangular pipe sections.

3. A ventilation and sound insulation array structure design method for manufacturing the ventilation and sound insulation array according to any one of claims 1-2, characterized in that: The specific steps include: S1, the length and width of the silencer unit are both L, and the wall thickness of the silencer unit is t; the widths of the throats on both sides are recorded as LW a -t with LW b -t, height is recorded as H; S2. Determine the frequency range of the noise to be isolated by measuring the spectrum of the noise to be isolated; S3. Using the acoustic-electrical analogy method, the throat is considered as the sound sensor and the cavity in the middle is considered as the sound volume to obtain the operating frequency of the anechoic unit; S4, connecting the silencer units with determined size parameters in series to form a silencer column; S5. Arrange M identical silencer columns side by side periodically with a spacing of D, ensuring that the throats on both sides of the silencer units in the silencer column are connected to the ventilation gaps on both sides.

4. A ventilation and sound insulation array structure design method according to claim 3, characterized in that: W of the previous unit b With the next unit W a The values ​​are the same and the operating frequencies are evenly covered.

5. A ventilation and sound insulation array structure design method according to claim 3, characterized in that: The operating frequency of each muffler unit is derived based on the equivalent circuit model: ； The effective pipe length is: , opening area: ; Consider the middle cavity as a capacitor: ； in The cavity volume is: , speed of sound: , air density ; The sound pressures at the left and right openings are denoted as p1 and p2 respectively, and the sound pressure inside the cavity is denoted as p. The circuit expression is written as: ； Derived unit size L, W a 、W b The relationship between it and the operating frequency f is: ； In the formula , ; Confirm the operating frequency of each silencer unit and determine the operating frequency range of the silencer column or the entire ventilation and sound insulation array, that is, the frequency range of sound that the array can effectively isolate.

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