CN216048296U - Noise elimination structure suitable for heating and ventilating system air port - Google Patents
Noise elimination structure suitable for heating and ventilating system air port Download PDFInfo
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- CN216048296U CN216048296U CN202122120718.2U CN202122120718U CN216048296U CN 216048296 U CN216048296 U CN 216048296U CN 202122120718 U CN202122120718 U CN 202122120718U CN 216048296 U CN216048296 U CN 216048296U
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Abstract
The utility model discloses a silencing structure suitable for a tuyere of a heating and ventilating system, which is formed by encircling a plurality of silencing units, wherein the center of the encircling is a vent; the silencing unit comprises an outer layer sound absorption structure and an inner layer sound absorption structure arranged in the outer layer sound absorption structure; the outer layer sound absorption structure comprises a closed shell, a first back cavity is formed in the closed shell, and a micro-perforated plate is arranged on one side, close to the ventilation opening, of the closed shell; the inner layer sound absorption structure comprises a plurality of semi-closed shells distributed at intervals and with openings facing the ventilation openings, a slit is formed between every two adjacent semi-closed shells, and a plurality of semi-closed shells are arranged on the side, located on the micro-perforated plate side, of each semi-closed shell to form a closed plate used for forming a second back cavity. The utility model has compact structure, realizes high-performance noise elimination and can keep the original ventilation effect.
Description
Technical Field
The utility model relates to the technical field of noise elimination, in particular to a noise elimination structure suitable for a heating and ventilation system air port.
Background
The heating and ventilation system wind gap is accompanied with noise, which affects the indoor environment. The noise reduction measures (such as ventilation silencer) adopted for the air opening should ensure the effective ventilation section of the original air flow channel as much as possible, and reduce the pressure loss caused by the noise reduction measures so as to ensure the ventilation effect. The existing ventilation silencer technology mostly adopts a resistive silencer made of porous sound absorption materials, and the resistive silencer is arranged at an air inlet and an air outlet or in an airflow channel, so that the noise at the air inlet and the air outlet is reduced, the noise elimination quantity of the resistive silencer at a middle-high frequency band is relatively high, but the noise elimination quantity at a low frequency band is obviously insufficient. Meanwhile, the length of the silencer is larger. In recent years, the development of acoustic metamaterials has provided new ideas for noise control, particularly low frequency noise control.
Patent specification CN109243419A discloses a ventilation and sound insulation structure composed of a central ventilation hole and a plurality of labyrinth-shaped walkways around, which realizes sound insulation performance in a wide frequency range by designing sound cavity runners with different lengths, but the labyrinth walkways in the structure occupy a large space and have poor ventilation performance. Patent specification CN112435646A discloses a zigzag-shaped sound insulator consisting of a central vent hole and a shell structure with a cavity at the periphery, wherein the side wall of the central vent channel is composed of a film provided with a plurality of weights, and the transmission of sound waves in the channel is blocked by selecting the eigenfrequency of the film. However, thin film materials have problems of being easily worn, having limited structural strength, and having stress that is difficult to maintain for a long time. Patent specification CN110822206A discloses a sound absorption structure with high ventilation efficiency, which includes two split tube resonators symmetrically arranged side by side, and is suitable for high-efficiency absorption of low-frequency sound, but the sound absorption band is narrow.
SUMMERY OF THE UTILITY MODEL
Aiming at the defects in the prior art, the utility model aims to provide a compact silencing structure suitable for a heating and ventilating system air port, which realizes high-performance silencing and keeps the original ventilating effect.
In order to achieve the purpose, the utility model adopts the following technical scheme:
a silencing structure suitable for a heating and ventilation system air port is formed by encircling a plurality of silencing units, and the center of the encircling is a ventilation opening;
the silencing unit comprises an outer layer sound absorption structure and an inner layer sound absorption structure arranged in the outer layer sound absorption structure; the outer layer sound absorption structure comprises a closed shell, a first back cavity is formed in the closed shell, and a micro-perforated plate is arranged on one side, close to the ventilation opening, of the closed shell;
the inner layer sound absorption structure comprises a plurality of semi-closed shells distributed at intervals and with openings facing the ventilation openings, a slit is formed between every two adjacent semi-closed shells, and a plurality of semi-closed shells are arranged on the side, located on the micro-perforated plate side, of each semi-closed shell to form a closed plate used for forming a second back cavity.
And designing a silencing unit according to the frequency spectrum characteristic of the airflow noise, wherein each structural parameter comprises the thickness, the perforation aperture, the perforation rate, the depth of a first back cavity, the width and the length of a slit structure, the depth of a second back cavity and the like. The width and length of the slit structure can be adjusted by changing the spacing and height of the semi-closed shell. By adjusting the structural parameters of the silencing unit, the natural frequency of the two resonance sound absorption results (the sound absorption structure of the micro-perforated plate and the slit sound absorption structure) is close to the noise frequency of the air flow to be controlled.
When sound waves are incident on the silencing unit, air columns in the perforated hole necks and the slits of the micro-perforated plates generate strong vibration due to resonance, and the air columns rub with the side walls of the hole necks and the side walls of the slits to consume sound energy, so that high-efficiency silencing of noise at two frequency points and nearby frequency is realized.
Preferably, the inner sound absorption structure comprises a plurality of rows of semi-closed shells distributed at intervals, the slits are also formed between adjacent semi-closed shells of adjacent rows, and the second back cavities corresponding to the rows are communicated.
Preferably, the top of the semi-enclosed housing is recessed downwardly to form a recess with an opening facing away from the microperforated plate.
The depth of the groove is similar to or the same as the height of the semi-closed shell, so that a plurality of curled channels can be formed, sound waves incident from the micro-porous plate are transmitted to different grooves and have different sound paths, reflected waves are formed by reflection of the grooves, the reflected waves transmitted along different directions formed by the same groove meet in the first back cavity or meet incident waves with corresponding wavelengths, and when the difference of the sound paths of two rows of sound waves is 1/2 with the target frequency corresponding to the wavelength, the sound energy of the sound waves with the corresponding frequencies can be consumed by eddy currents formed through destructive interference. Meanwhile, the depth of the groove is designed to be 1/4 of the wavelength corresponding to the noise frequency to be controlled, sound waves enter the groove through the groove opening, if the sound path difference of the sound waves reflected at the bottom of the groove and returned to the opening is just 1/2 of the wavelength corresponding to the target frequency, destructive interference is generated at the groove opening by the sound waves with the frequency, the sound energy is reduced, the sound attenuation performance of the sound attenuation unit can be further improved, and the sound attenuation frequency band is widened.
Preferably, the opening of the semi-closed shell can be closed by a bottom plate arranged at the opening position, and one or more through holes are formed in the bottom plate.
The semi-closed shell is in a cuboid or other closed structures, holes are formed in the face close to the ventilation openings, a plurality of Helmholtz resonant cavities connected in parallel can be additionally introduced, and the noise elimination performance of the semi-closed shell is further improved.
Preferably, the vent is provided with a partition for uniformly partitioning the vent, and the partition is composed of back-to-back overlapped silencing units.
Specifically, the partition can be increased according to the actual size of the ventilation opening so as to improve the upper limit cut-off frequency of the noise elimination structure.
Preferably, the inner sound absorption structure is spaced from the inner walls of the closed casing by the same distance.
Preferably, the outer layer sound absorption structure and the inner layer sound absorption structure are made of aluminum alloy, stainless steel or plastic; such as steel plate or acrylic plate.
The utility model has the beneficial effects that:
the silencing structure can realize high-performance silencing and hardly reduces the ventilation effect (ventilation volume and wind speed) of the original air port. Meanwhile, the silencing unit is integrated with a micro-perforated plate resonance sound absorption structure, a plurality of parallel slit resonance sound absorption structures, a plurality of curled acoustic channels with different sound paths, a plurality of parallel Helmholtz resonant cavities and the like, so that broadband silencing is realized while the low-frequency silencing effect is ensured.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic structural view of the muffler unit of the present invention;
FIG. 3 is a cross-sectional view of the muffler unit of the present invention;
FIG. 4 is a schematic view of a groove built in a semi-enclosed housing;
FIG. 5 is a schematic view of an inner layer sound absorbing structure comprising a plurality of rows of semi-enclosed housings;
FIG. 6 is a schematic view of a two degree of freedom mass spring system;
FIG. 7 is a spectrum of noise at the warm ventilation opening;
FIG. 8 is a schematic view of a result of a simulation calculation of sound absorption coefficient of the sound attenuation structure of the present invention;
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1-3, a silencing structure suitable for a tuyere of a heating and ventilating system is characterized in that four silencing units 1 surround to form a square shape, and the center of the surrounding shape is a ventilation opening.
The silencing unit 1 comprises an outer layer sound absorption structure and an inner layer sound absorption structure arranged in the outer layer sound absorption structure; the outer layer sound absorption structure comprises a closed shell 11, a first back cavity 111 is formed in the closed shell 11, and a micro-perforated plate 112 is arranged on one side, close to the ventilation opening, of the closed shell 11;
the inner layer sound absorption structure comprises a plurality of semi-closed shells 12 which are distributed at intervals and have openings facing the ventilation openings, a slit 121 is formed between every two adjacent semi-closed shells 12, a plurality of semi-closed shells 12 are provided with a closing plate 122 at the side of the micro-perforated plate 112, and a second back cavity 123 is formed between the closing plate 122 and the semi-closed shells 12; specifically, the closing plate 122 may extend downward through the side walls of the two side semi-closed casings 12 and then extend and close to the inner sides, and the front and rear sides are closed by the inner walls of the closed casing 11; or by providing an outer frame outside (except for the top) the plurality of semi-enclosed housings 12 to form a second back cavity 123. Wherein, outer sound absorption structure and inlayer sound absorption structure can be made by rigidity material such as steel sheet or ya keli board.
In some embodiments, as shown in fig. 4, the top of the semi-enclosed housing 12 is recessed downward to form a groove 124 with an opening facing away from the microperforated panel 112, so that a plurality of curled channels can be formed, and the sound-damping performance of the sound-damping unit 1 can be further improved, and the sound-damping frequency band can be broadened. Wherein the width d of the groove 124 is larger than 5 mm.
In some embodiments, the opening of the semi-enclosed housing 12 is closed by a bottom plate (not shown) disposed at the opening position, and the bottom plate is provided with one or more through holes, so that a plurality of helmholtz resonance chambers connected in parallel can be additionally introduced to further improve the noise elimination performance.
In some embodiments, as shown in fig. 5, the inner sound absorbing structure includes a plurality of rows of semi-enclosed casings 12 spaced apart from each other, and slits 121 are formed between adjacent semi-enclosed casings 12 of adjacent rows, and the corresponding second back cavities 123 of each row are communicated with each other; specifically, by providing an outer frame, communication of the second back chamber 123 has been achieved; or an independent outer frame is arranged outside each row of the semi-closed shell 12, so that the second back cavities 123 corresponding to each row are independent.
In some embodiments, partitions can be added according to the actual size of the ventilation openings to uniformly divide the ventilation openings, and the partitions are composed of the silencing units 1 which are overlapped back to back so as to improve the upper limit cut-off frequency of the silencing structure.
The silencing unit 1 can be equivalent to a classical two-degree-of-freedom mass spring system, as shown in the figure6, their equivalent stiffness is respectively K1And K2The equivalent mass is M1And M2. Suppose K1＝K2＝2K0，K0For an equivalent stiffness of a single degree of freedom mass spring system, the natural frequency fi (i ═ 1, 2) of the system can be expressed as
When the frequency of incident sound wave and the natural frequency f of systemiWhen the difference is equal, the air column in the throat and between the slits vibrates sharply due to resonance, and during vibration, the air column rubs against the side wall of the throat and the side wall of the slits, thereby consuming acoustic energy.
According to the actually measured noise spectrum at the warm-air vent, as shown in fig. 7, the noise radiated at the vent is mainly medium and low frequency noise, and the sound pressure level reaches the peak value near 1 kHz. And designing parameters of the silencing structure by taking the noise reduction as a target. As shown in FIG. 3, the microperforated plate 112 had a plate thickness t of 0.5mm and a perforation hole diameter r20.6mm, a perforation rate of 0.01; the first back cavity 111 has a width L of 200mm and a depth D1Is 60 mm. Width r of semi-enclosed housing 12118mm, height l 20 mm; second rear cavity 123 depth D2Is 40 mm. The inner layer sound absorption structure is equal to the inner wall of the closed shell 11 in distance, and the distance s is 10 mm. The height of the muffler unit 1 is 70 mm.
In order to verify the silencing performance of the silencing structure, simulation calculation is carried out on the silencing unit 1 by adopting COMSOL Multiphysics 5.5, and the calculation result is shown in a figure 8. As can be seen from fig. 8, the sound attenuation structure has good sound attenuation performance in the middle and low frequency range, has high sound absorption coefficients near 400Hz and 1kHz, and the sound absorption coefficients are both greater than 0.95.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the utility model can be made, and equivalents and modifications of some features of the utility model can be made without departing from the spirit and scope of the utility model.
Claims (8)
1. The utility model provides a noise cancelling structure suitable for warm logical system wind gap which characterized in that: the silencing structure is formed by encircling a plurality of silencing units, and the center of the encircling is a ventilation opening;
the silencing unit comprises an outer layer sound absorption structure and an inner layer sound absorption structure arranged in the outer layer sound absorption structure; the outer layer sound absorption structure comprises a closed shell, a first back cavity is formed in the closed shell, and a micro-perforated plate is arranged on one side, close to the ventilation opening, of the closed shell;
the inner layer sound absorption structure comprises a plurality of semi-closed shells distributed at intervals and with openings facing the ventilation openings, a slit is formed between every two adjacent semi-closed shells, and a plurality of semi-closed shells are arranged on the side, located on the micro-perforated plate side, of each semi-closed shell to form a closed plate used for forming a second back cavity.
2. The silencing structure for a tuyere of a heating and ventilating system according to claim 1, wherein: the inner layer sound absorption structure comprises a plurality of rows of semi-closed shells distributed at intervals, the slits are also formed between adjacent semi-closed shells of adjacent rows, and the corresponding second back cavities of the rows are communicated.
3. The silencing structure for a tuyere of a heating and ventilating system according to claim 1, wherein: the inner layer sound absorption structure comprises a plurality of rows of semi-closed shells distributed at intervals, and the second back cavities corresponding to the rows are independent.
4. The silencing structure for a tuyere of a heating and ventilating system according to claim 1, wherein: the top of the semi-closed shell is downwards sunken to form a groove with an opening back to the micro-perforated plate.
5. The silencing structure for a tuyere of a heating and ventilating system according to claim 1, wherein: the opening of the semi-closed shell is closed by a bottom plate arranged at the opening position, and the bottom plate is provided with one or more through holes.
6. The silencing structure for a tuyere of a heating and ventilating system according to claim 1, wherein: the ventilation opening is provided with partitions for uniformly partitioning the ventilation opening, and the partitions are composed of back-to-back overlapped silencing units.
7. The silencing structure for a tuyere of a heating and ventilating system according to claim 1, wherein: and the distance between the inner sound absorption structure and each inner wall of the closed shell is equal.
8. The silencing structure for a tuyere of a heating and ventilating system according to claim 1, wherein: the outer layer sound absorption structure and the inner layer sound absorption structure are made of aluminum alloy, stainless steel or plastic.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122120718.2U CN216048296U (en) | 2021-09-03 | 2021-09-03 | Noise elimination structure suitable for heating and ventilating system air port |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122120718.2U CN216048296U (en) | 2021-09-03 | 2021-09-03 | Noise elimination structure suitable for heating and ventilating system air port |
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| Publication Number | Publication Date |
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| CN216048296U true CN216048296U (en) | 2022-03-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202122120718.2U Active CN216048296U (en) | 2021-09-03 | 2021-09-03 | Noise elimination structure suitable for heating and ventilating system air port |
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