WO2022001831A1

WO2022001831A1 - Silencing unit, and honeycomb muffler

Info

Publication number: WO2022001831A1
Application number: PCT/CN2021/102144
Authority: WO
Inventors: 刘兆恒; 李帅; 刘帆; 徐青松
Original assignee: 中兴通讯股份有限公司
Priority date: 2020-06-29
Filing date: 2021-06-24
Publication date: 2022-01-06
Also published as: CN113936630A

Abstract

Disclosed are a silencing unit and a honeycomb muffler. The silencing unit (10) comprises an outer ring (102) and a central body (104), wherein the outer ring (102) is composed of a first sound absorbing material and comprises a hollow cavity; the central body (104) is composed of a second sound absorbing material and is arranged in the hollow cavity; a silencing channel (106), which is used for having an airflow pass therethrough, is formed between an inner surface of the hollow cavity of the outer ring (102) and an outer surface of the central body (104), and the cross-section of the silencing channel (106) varies in the direction of the airflow passing through. The silencing unit solves the problem of how to improve the noise reduction effect of a silencing unit in a limited space, thus improving a comprehensive noise reduction effect.

Description

Muffler units and cellular mufflers

This application claims the priority of the Chinese patent application filed on June 29, 2020, with the application number 202010606307.1 and the invention title "Muffler Unit and Honeycomb Muffler", the entire contents of which are incorporated into this application by reference.

technical field

The embodiments of the present disclosure relate to the technical field of noise reduction and noise reduction of equipment, and in particular, to a noise reduction unit and a cellular muffler.

Background technique

The power consumption of communication equipment is huge, and a large number of axial fans are usually used for heat dissipation; while the communication industry stipulates that the noise standard of unattended communication equipment room equipment is less than 75dBA, and the noise standard of manned communication equipment room equipment is less than 72dBA; When the heat dissipation of the equipment is satisfied, there is a risk of excessive noise, and the noise will also endanger human health and safety. Therefore, it is usually necessary to install a muffler for noise reduction and noise reduction.

With the development of the times, the power consumption of communication equipment has increased significantly, but the noise standard of the computer room has not been lowered. The ordinary muffler can no longer meet the noise reduction needs of communication equipment. In the future, the contradiction between the structure size, heat dissipation and noise of communication equipment will become more prominent. Noise faces a huge challenge. In fact, not only communication equipment, but other types of equipment also face the same problem. How to improve the noise reduction effect of the muffler unit in a limited space is an urgent problem to be solved by those skilled in the art.

public content

Embodiments of the present disclosure provide a muffler unit and a honeycomb muffler to at least solve the problem of how to improve the noise reduction effect of the muffler unit in a limited space.

According to an embodiment of the present disclosure, there is provided a sound-absorbing unit, comprising: an outer ring and a central body, wherein the outer ring is composed of a first sound-absorbing material and has a hollow cavity; the central body is composed of a second sound-absorbing material It is made of sound material and is arranged in the hollow cavity; a sound reduction channel for air flow is formed between the inner surface of the hollow cavity of the outer ring and the outer surface of the central body, and the sound reduction channel The cross section of the air flow varies along the direction in which the airflow passes.

In at least one exemplary embodiment, the thickness of the first sound absorbing material constituting the outer ring varies continuously along the direction in which the airflow passes.

In at least one exemplary embodiment, the inner surface of the hollow cavity of the outer ring extends in a streamline or straight line along the direction in which the airflow passes.

In at least one exemplary embodiment, the thickness of the second sound absorbing material constituting the central body varies continuously along the direction in which the airflow passes.

In at least one exemplary embodiment, the central body is disposed in the center of the hollow cavity of the outer ring.

In at least one exemplary embodiment, the muffling unit is used to be mounted on a device having a fan, and the size of the cross-section of the central body at the end of the muffling unit close to the fan is the same as that of the fan. to match the size of the wheels.

In at least one exemplary embodiment, a position of the center body at an end of the muffler unit close to the fan matches a position of a hub of the fan.

In at least one exemplary embodiment, the central body is conical or streamlined or frustoconical.

In at least one exemplary embodiment, the first sound absorbing material and the second sound absorbing material comprise a porous dielectric material having sound absorbing properties.

In at least one exemplary embodiment, a surface of the outer ring and/or the central body is covered with a cladding material, wherein the cladding material has an anechoic effect on sound waves of a predetermined frequency.

In at least one exemplary embodiment, the cladding material includes one of the following: perforated plate material, micro-perforated plate material, film cladding material.

According to an embodiment of the present disclosure, there is provided a honeycomb muffler, comprising: a housing and a plurality of muffler units according to any one of the above embodiments, wherein the plurality of muffler units are arranged in the housing.

In at least one exemplary embodiment, adjacent sound-absorbing units are in contact with each other; and/or, a sound-absorbing unit in the plurality of sound-absorbing units that is close to the outer casing is in contact with the outer casing. .

Through the present disclosure, since the muffler channel formed between the outer ring and the central body in the muffler unit has the characteristic of changing cross-section along the direction in which the airflow passes, the path length of the sound wave transmission in the muffler channel is effectively increased, thereby improving the muffler. Noise reduction effect. Therefore, the problem of how to improve the noise reduction effect of the muffler unit in a limited space can be solved.

Description of drawings

FIG. 1a is a schematic structural diagram of the center body 104 in the muffler unit 10 according to an embodiment of the present disclosure;

FIG. 1b is a schematic structural diagram of the outer ring 102 in the muffler unit 10 according to an embodiment of the present disclosure;

FIG. 1c is a schematic structural diagram of the muffler unit 10 according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of an exemplary structure of the muffling unit 10 according to an embodiment of the present disclosure;

3 is a schematic structural diagram of a honeycomb muffler 20 according to an embodiment of the present disclosure;

4 is a schematic structural diagram of the muffling unit 10 according to Example 1 of the present disclosure;

5 is a schematic structural diagram of the muffler unit 10 according to Example 2 of the present disclosure;

FIG. 6 is a schematic structural diagram of the muffling unit 10 according to Example 3 of the present disclosure.

10: Muffler unit

20: Honeycomb muffler

102: Outer Ring

104: Centrosome

106: Muffler channel

108: Covering material

detailed description

Common mufflers for equipment (for example, communication equipment cabinets) usually include chip, folded, and cellular (matrix) mufflers. Noise reduction is mainly achieved by utilizing the sound absorption properties of porous media materials. However, the common muffler has the following problems: due to the limited space in the computer room, the depth space of the muffler in the communication equipment cabinet is limited, generally not exceeding 200mm, and the length of the muffler channel is short, which affects the comprehensive noise reduction effect of the muffler. In addition, due to the sound absorption characteristics of the porous medium material itself, the noise reduction performance of the muffler at low frequencies is poor. Since the effective frequency of noise reduction of porous dielectric materials is strongly related to the thickness, the thickness of the porous material in the muffler channel of ordinary mufflers is the same, resulting in a limited bandwidth of effective noise reduction.

In order to solve at least one of the above problems, an embodiment of the present disclosure provides a muffler with a variable-section channel and a honeycomb-type muffler with such a muffler. The muffler is designed to cooperate with a central sound absorbing body by adopting a variable-section channel design. , Under the premise of the same space occupation, the low-frequency noise reduction effect is improved, and the effective noise reduction frequency bandwidth is increased. In addition, by coating the surface of the porous sound-absorbing material, it is possible to further target noise reduction for specific frequencies and enhance the sound-absorbing effect of the muffler.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings and in conjunction with the embodiments.

It should be noted that the terms "first", "second" and the like in the description and claims of the present disclosure and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence.

The muffler unit and the cellular muffler including the muffler unit provided in the embodiments of the present application can be used for various types of devices that generate noise during operation, including communication devices and the like. Taking communication equipment as an example, the muffler unit or the honeycomb muffler including a plurality of muffler units can be connected to the communication equipment through but not limited to screw fastening, riveting and other processes.

The structure of the muffler unit for muffling equipment according to the embodiment of the present disclosure will be described in detail below. FIG. 1a is a schematic structural diagram of the center body 104 in the muffler unit 10 according to the embodiment of the present disclosure; FIG. 1b is according to the present disclosure. Schematic diagram of the structure of the outer ring 102 in the muffler unit 10 of the embodiment; FIG. 1 c is a schematic diagram of the structure of the muffler unit 10 according to the embodiment of the present disclosure. As shown in FIG. 1c, the muffler unit 10 includes an outer ring 102 and a central body 104, wherein the outer ring 102 is made of a first sound absorbing material and has a hollow cavity (the body of the outer ring 102 and the hollow cavity it has are such as 1b); the central body 104 is made of a second sound-absorbing material (the body of the central body 104 is shown in Figure 1a), and is arranged in the hollow cavity; the inner part of the hollow cavity of the outer ring 102 Between the surface and the outer surface of the central body 104 is formed a muffler channel 106 for air flow, and the cross section of the muffler channel 106 changes along the direction of the air flow (the outer ring 102 and the central body 104 together The muffling channel 106 is formed as shown in Figure 1c).

Through this solution, since the muffling channel 106 formed between the outer ring 102 and the central body 104 in the muffling unit 10 has the characteristic of changing the cross-section along the direction in which the airflow passes, the path of sound wave transmission in the muffling channel 106 is effectively increased. length, thereby improving the noise reduction effect of the muffler. Therefore, the problem of how to improve the noise reduction effect of the muffler unit in a limited space can be solved.

It should be noted that the above FIGS. 1 a to 1 c only exemplarily show the streamlined outer ring 102 and the conical center body 104 , but the solutions of the embodiments of the present disclosure are not limited to the shown outer ring 102 and the conical center body 104 . The form of the central body 104 . Compared with the structure of the muffler unit 10 of the honeycomb muffler in the related art, the cross section of the muffler channel 106 can be changed along the direction of the airflow to increase the path length. The inner surface of the hollow cavity and the central body 104 There is no special requirement for the shape of the specific curved surface of the outer surface, as long as the muffler channel 106 formed between the two has the property of changing the cross-section along the direction of the airflow passing, the effect of increasing the path length can be achieved, thereby improving the Muffler noise reduction effect.

In at least one exemplary embodiment, the thickness of the first sound absorbing material constituting the outer ring 102 varies continuously along the direction in which the airflow passes. For example, in at least one exemplary embodiment, the inner surface of the hollow cavity of the outer ring 102 extends in a streamlined manner in the direction in which the airflow passes. When the inner surface of the hollow cavity of the outer ring extends in a flow shape, the noise reduction channel 106 is made in a streamline shape, which can effectively reduce the airflow resistance and improve the comprehensive noise reduction effect. For example, in at least one exemplary embodiment, the inner surface of the hollow cavity of the outer ring 102 extends linearly along the direction in which the airflow passes, and the linear hollow cavity has the advantage of being easy to process.

In at least one exemplary embodiment, the thickness of the second sound absorbing material constituting the central body 104 varies continuously along the direction in which the airflow passes. For example, in at least one exemplary embodiment, the central body 104 is conical or streamlined or frustoconical. The conical and streamlined central body 104 can effectively reduce the airflow resistance and improve the comprehensive noise reduction effect, and the circular truncated central body 104 also has the advantage of being easy to process.

In the embodiment of the present disclosure, due to the use of the outer ring 102 and the central body 104 whose thickness varies continuously along the direction of the airflow, the sound waves are reflected and propagated between the sound absorbing materials of different thicknesses in the channel, and the sound waves of different frequencies gradually It is absorbed, which increases the effective noise reduction frequency band; in addition, the sound wave has interference phenomenon in the channel, which also plays a certain role in noise reduction.

In at least one exemplary embodiment, the central body 104 is disposed in the center of the hollow cavity of the outer ring 102 . By arranging the central body 104 in the center of the hollow cavity of the outer ring 102, on the one hand, a more balanced noise reduction effect can be achieved, and on the other hand, the noise cancellation unit 10 can be geometrically symmetrical, which is a good way to reduce the noise Mounting of the unit 10 to equipment or assembly as a cellular muffler provides convenience.

In at least one exemplary embodiment, the muffling unit 10 is used for installation on a device having a fan, and the size of the cross-section of the central body 104 at the end of the muffling unit 10 near the fan is the same as The size of the fan hub is matched. In at least one exemplary embodiment, the position of the central body 104 at the end of the muffler unit 10 close to the fan matches the position of the hub of the fan. With this design, the obstruction to airflow is minimized.

In at least one exemplary embodiment, the first sound absorbing material and the second sound absorbing material include porous media materials having sound absorbing properties, for example, may be sound absorbing cotton, glass fibers, or other porous media materials. It should be noted that the first sound-absorbing material and the second sound-absorbing material may be the same sound-absorbing material or different sound-absorbing materials. The absorption spectrum characteristics of the noise and the frequency band composition structure of the noise generated by the device are selected, which are not specifically limited in this embodiment of the present disclosure.

FIG. 2 is an exemplary structural schematic diagram of the muffler unit 10 according to an embodiment of the present disclosure. As shown in FIG. 2 , in at least one exemplary embodiment, the outer ring 102 and/or the surface sticker of the central body 104 is There is a cladding material 108, wherein the cladding material 108 has a sound dampening effect on sound waves of a predetermined frequency. In at least one exemplary embodiment, the cladding material 108 includes one of the following: a perforated sheet material, a micro-perforated sheet material, a film cladding material. In practical applications, the specific parameters of the cladding material 108 can be obtained by theoretical calculation according to the noise spectrum to be suppressed.

The structure of the cellular muffler for muffling equipment according to an embodiment of the present disclosure will be described in detail below. FIG. 3 is a schematic structural diagram of a cellular muffler 20 according to an embodiment of the present disclosure. As shown in FIG. 3 , the cellular muffler 20 , comprising: a casing 12 and a plurality of muffler units 10 , wherein the plurality of muffler units 10 are arranged in the casing 12 .

Referring to FIG. 1c for an exemplary structure of each sound-absorbing unit 10, as shown in FIG. 1c, the sound-absorbing unit 10 includes an outer ring 102 and a central body 104, wherein the outer ring 102 is composed of a first sound absorbing material with A hollow cavity (the main body of the outer ring 102 and its hollow cavity are shown in Figure 1b); the central body 104 is made of a second sound-absorbing material (the main body of the central body 104 is shown in Figure 1a), which is arranged in the hollow cavity In the middle; between the inner surface of the hollow cavity of the outer ring 102 and the outer surface of the central body 104, a muffler channel 106 for air flow is formed, and the cross section of the muffler channel 106 is along the The direction of air flow changes (the outer ring 102 and the central body 104 together form the muffling channel 106 as shown in Figure 1c).

In at least one exemplary embodiment, adjacent muffler units 10 are attached to each other; and/or, a muffler unit 10 of the plurality of muffler units 10 that is close to the housing 12 and the housing 12 fit in between. By closely fitting the adjacent muffler units 10 and the muffler unit 10 and the housing 12 closely, a better muffling effect can be achieved.

With this solution, since the muffler channel 106 formed between the outer ring 102 and the center body 104 in the muffler unit 10 of the honeycomb muffler 20 has the characteristic of changing cross-section along the direction in which the airflow passes, the muffler channel 106 is effectively increased. The path length of the internal sound wave transmission, thereby improving the overall noise reduction effect of the honeycomb muffler 20 . Therefore, the problem of how to improve the noise reduction effect of the cellular muffler 20 in a limited space can be solved.

Compared with the structure of the muffler unit 10 of the honeycomb muffler in the related art, the cross section of the muffler channel 106 of each muffler unit 10 in the honeycomb muffler 20 in the present embodiment varies along the direction in which the airflow passes, that is, The length of the path can be increased, and the shape of the specific curved surface of the inner surface of the hollow cavity and the outer surface of the central body 104 has no special requirements, as long as the muffling channel 106 formed between the two has a change in the direction of the airflow passing through. The nature of the section can achieve the effect of increasing the path length, thereby improving the noise reduction effect of the muffler.

In at least one exemplary embodiment, the central body 104 is disposed in the center of the hollow cavity of the outer ring 102 . By arranging the central body 104 in the center of the hollow cavity of the outer ring 102, on the one hand, a more balanced noise reduction effect can be achieved, and on the other hand, the noise cancellation unit 10 can be geometrically symmetrical, which is a good way to reduce the noise Mounting of the unit 10 to equipment or assembly into a cellular muffler 20 provides convenience.

In at least one exemplary embodiment, the honeycomb muffler 20 is for mounting on a device having a fan, and the center body 104 is at the end of the muffler unit 10 of the honeycomb muffler 20 near the fan. The size of the cross section matches the size of the hub of the fan. In at least one exemplary embodiment, the position of the central body 104 at the end of the muffler unit 10 of the honeycomb muffler 20 near the fan matches the position of the hub of the fan. With this design, the obstruction to airflow is minimized.

In at least one exemplary embodiment, a surface of the outer ring 102 and/or the central body 104 is covered with a cladding material 108 , wherein the cladding material 108 has a sound attenuation effect on sound waves of a predetermined frequency. In at least one exemplary embodiment, the cladding material 108 includes one of the following: a perforated sheet material, a micro-perforated sheet material, a film cladding material. In practical applications, the specific parameters of the cladding material 108 can be obtained by theoretical calculation according to the noise spectrum to be suppressed.

For specific examples in this embodiment, reference may be made to the examples described in the foregoing embodiments and exemplary implementation manners, and details are not described herein again in this embodiment.

The structure of the cellular muffler 20 and the muffler unit 10 in the embodiment of the present disclosure will be described in detail below by taking a cellular muffler 20 applied to a variable cross-section channel of a communication device as an example.

The honeycomb muffler 20 with variable cross-section channel includes a cuboid shell 12 and a plurality of muffler units 10 .

The cuboid housing 12 can be connected with the communication device through but not limited to screw fastening, riveting and other processes.

The muffler unit 10 is provided with a muffler channel 106 along the axial direction. The muffler unit 10 includes an outer ring 102 of a sound-absorbing material, a center body 104 of the sound-absorbing material, and a coating material 108 on the surface of the sound-absorbing material. .

The sound-absorbing channel 106 refers to the airflow channel between the outer ring 102 of the sound-absorbing material and the central body 104 of the sound-absorbing material, and the channel is in the form of variable cross-section along the flow direction of the airflow.

The outer ring 102 of the sound-absorbing material is composed of sound-absorbing material whose thickness gradually changes along the airflow movement direction of the sound-absorbing channel, and the sound-absorbing material may be sound-absorbing cotton, glass fiber, or other porous media materials.

The center body 104 of the sound-absorbing material is composed of sound-absorbing material whose thickness gradually changes along the airflow movement direction of the sound-absorbing channel, and is located in the center of the air duct formed by the outer ring of the sound-absorbing material, and the diameter near the fan side is the same as the size of the fan hub, This minimizes obstruction to airflow. The sound-absorbing material may be sound-absorbing cotton, glass fiber, or other porous media materials.

The coating material 108 on the surface of the sound-absorbing material is closely attached to the outer ring 102 of the sound-absorbing material and the surface of the center body 104 of the sound-absorbing material, and can be a perforated plate, a micro-perforated plate, a film covering material, or the like.

The effective noise reduction frequency band of the sound absorbing material is strongly related to the thickness. The thicker the thickness, the better the low frequency noise reduction effect. When the sound wave enters the sound-absorbing channel, firstly, the specific frequency is reduced through the coating material 108 on the surface of the sound-absorbing material, and then the sound-absorbing material is passed through the outer ring 102 and the center body 104 of the sound-absorbing material. frequency muting.

The variable-section muffler channel increases the path length of sound wave transmission and improves the noise reduction effect of the muffler; the sound wave is reflected and propagated between sound absorbing materials of different thicknesses in the channel, and the sound waves of different frequencies are gradually absorbed, increasing the effective noise reduction frequency band ; In addition, there is interference phenomenon of sound waves in the channel, which also plays a certain role in noise reduction.

Through the above solution, the effective noise reduction frequency bandwidth is increased without increasing the space occupied by the muffler, the low frequency noise reduction effect is improved, and the comprehensive noise reduction effect of the honeycomb muffler 20 is improved. For example, within the depth limit of 200mm, the comprehensive noise reduction amount of the folding plate muffler applied to the core router after considering the heat dissipation is 3dBA, and the comprehensive noise reduction amount of the ordinary honeycomb muffler is 4dBA; The noise reduction channel honeycomb muffler 20, under the same external dimensions, the comprehensive noise reduction amount can reach 6dBA, and the noise reduction effect is significantly improved.

Several exemplary structures of the muffler unit 10 are given below. It should be noted that the following examples are only used to illustrate the structure of the muffler unit 10 that is preferred and commonly used in practical applications, and are not used to improperly limit the scope of the present disclosure. .

Example 1

FIG. 4 is a schematic structural diagram of the muffler unit 10 according to Example 1 of the present disclosure. As shown in FIG. 4 , the muffler unit 10 consists of an outer ring 102 of a sound absorbing material, a center body 104 of the sound absorbing material, and the sound absorbing material. The surface coating material 108 is composed.

The outer ring 102 of the sound-absorbing material is streamlined, the sound-absorbing material is sound-absorbing cotton, the center body 104 of the sound-absorbing material is conical, and the covering material 108 on the surface of the sound-absorbing material is a micro-perforated plate. The parameters of the microperforated plate can be calculated theoretically according to the noise spectrum desired to be suppressed. The streamlined airflow channel can reduce airflow resistance and improve the overall noise reduction effect.

Example 2

FIG. 5 is a schematic structural diagram of the muffler unit 10 according to Example 2 of the present disclosure. As shown in FIG. 5 , the muffler unit 10 is composed of an outer ring 102 of a sound-absorbing material, a center body 104 of the sound-absorbing material, and the sound-absorbing material. The surface coating material 108 is composed. The difference from Example 1 is that the interface of the outer ring 102 of the sound absorbing material is linear, the center body 104 of the sound absorbing material is streamlined, and the coating material 108 on the surface of the sound absorbing material is a film coating material.

Example 3

FIG. 6 is a schematic structural diagram of the muffler unit 10 according to Example 3 of the present disclosure. As shown in FIG. 6 , the muffler unit 10 is composed of an outer ring 102 of a sound-absorbing material, a center body 104 of the sound-absorbing material, and the sound-absorbing material. The surface coating material 108 is composed. The difference from Example 1 is that the sound-absorbing material is glass fiber, the interface of the outer ring 102 of the sound-absorbing material is linear, the central body 104 of the sound-absorbing material is a circular truncated structure, and the coating material 108 on the surface of the sound-absorbing material is perforated. plate structure. The straight-shaped outer ring of sound-absorbing material and the conical-shaped sound-absorbing material center body improve the machinability of the muffler.

It can be seen from the embodiments and specific examples of the present disclosure that the muffler unit 10 has a muffler channel with a variable section, which increases the muffler channel path and improves the low-frequency muffling effect; in addition, the muffler unit 10 has a muffler center body with a variable section , the porous dielectric materials with different thicknesses broaden the effective noise reduction frequency band. Under the limitation of limited depth, the scheme improves the low-frequency sound absorption effect of the muffler, increases the effective noise reduction frequency bandwidth of the muffler, and improves the comprehensive noise reduction effect.

The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

A muffler unit, comprising: an outer ring and a center body, wherein,

the outer ring is composed of a first sound-absorbing material and has a hollow cavity;

the central body is composed of a second sound-absorbing material and is arranged in the hollow cavity;

A muffler channel is formed between the inner surface of the hollow cavity of the outer ring and the outer surface of the central body for the air flow to pass through, and the cross section of the muffler channel changes along the direction of the air flow passage.
The sound-absorbing unit according to claim 1, wherein the thickness of the first sound-absorbing material constituting the outer ring varies continuously along a direction in which the airflow passes.
The muffler unit according to claim 1, wherein the inner surface of the hollow cavity of the outer ring extends in a streamline or straight line along a direction in which the airflow passes.
The sound-absorbing unit according to claim 1, wherein the thickness of the second sound-absorbing material constituting the center body continuously changes along a direction in which the airflow passes.
The muffling unit of claim 1, wherein the center body is disposed at the center of the hollow cavity of the outer ring.
The muffling unit according to claim 1, wherein the muffling unit is used for installation on a device having a fan, the size of the cross section of the central body at an end of the muffling unit close to the fan Match the size of the hub of the fan.
The muffler unit according to claim 1, wherein the central body is in the shape of a cone or a streamline or a truncated cone.
The sound-absorbing unit of claim 1, wherein the first sound-absorbing material and the second sound-absorbing material comprise a porous dielectric material having sound-absorbing properties.
The muffler unit according to claim 1, wherein a surface of the outer ring and/or the central body is covered with a covering material, wherein the covering material has a muffling effect on sound waves of a predetermined frequency.
The muffler unit according to claim 9, wherein the cladding material comprises one of the following: a perforated plate material, a micro-perforated plate material, and a film cladding material.
A honeycomb muffler, comprising: a housing and a plurality of muffling units according to any one of claims 1-10, wherein the plurality of muffling units are arranged in the housing.
The honeycomb muffler according to claim 11, wherein adjacent muffler units are in contact with each other; and/or, a muffler unit close to the casing among the plurality of muffler units is connected to the casing. Fit in between.