WO2024113402A1 - 通风管道宽频超材料消音器及设计方法和应用 - Google Patents

通风管道宽频超材料消音器及设计方法和应用 Download PDF

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Publication number
WO2024113402A1
WO2024113402A1 PCT/CN2022/137550 CN2022137550W WO2024113402A1 WO 2024113402 A1 WO2024113402 A1 WO 2024113402A1 CN 2022137550 W CN2022137550 W CN 2022137550W WO 2024113402 A1 WO2024113402 A1 WO 2024113402A1
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Prior art keywords
broadband
ventilation duct
resonance unit
sound
duct
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PCT/CN2022/137550
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English (en)
French (fr)
Inventor
杨旻
陈书宇
肖松文
谢萌瑶
徐云飞
张晓男
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静音科技有限公司
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Publication of WO2024113402A1 publication Critical patent/WO2024113402A1/zh

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
    • F16L55/02—Energy absorbers; Noise absorbers
    • F16L55/033—Noise absorbers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/24—Means for preventing or suppressing noise
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/162—Selection of materials
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/162—Selection of materials
    • G10K11/168—Plural layers of different materials, e.g. sandwiches
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/172—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using resonance effects
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound

Definitions

  • the invention belongs to the technical field of noise processing, and in particular relates to a broadband metamaterial silencer and a design method and application thereof.
  • heat and material accumulation often occur due to various reasons. For example, heat is generated inside chips and machines running at high power, dust is accumulated during factory operations, and water vapor is accumulated in wearable devices due to human breathing and sweating. Therefore, it is very important to remove excess heat and material through air circulation.
  • Ventilation through ducts is a common solution. It has the advantages of high efficiency and simple design. Through the extraction and (or) pushing of the fan system, the air or other gas in the target space will carry the heat and accumulated substances into the duct system, and then be discharged along the designed path.
  • the purpose of the present invention is to provide a broadband metamaterial silencer for a ventilation duct and a design method and application thereof in order to solve the problems existing in the existing broadband noise reduction technology for ventilation ducts.
  • the main function of the pipe is to guide the airflow to circulate. Therefore, it is best not to cause too much obstruction to the pipe itself during the noise reduction operation.
  • the best way to achieve this requirement is to install sound insulation/sound absorbing materials on the side walls. For a given broadband target impedance, we can design multiple resonance units accordingly to achieve its acoustic characteristics.
  • one of the technical solutions of the present invention is a broadband metamaterial silencer for a ventilation duct, wherein the metamaterial silencer is a broadband metamaterial silencer outside the duct, or a broadband split-flow metamaterial silencer inside the duct, or a broadband metamaterial degenerate sound absorber;
  • the broadband noise reduction metamaterial silencer outside the pipeline includes a broadband sound isolator arranged outside the pipeline, a broadband sound absorber arranged outside the pipeline, or a combination of a broadband sound isolator and a broadband sound absorber arranged outside the pipeline;
  • the broadband split-flow metamaterial silencer in the pipeline includes a broadband sound isolator arranged in the pipeline, a broadband sound absorber arranged in the pipeline, or a combination of a broadband sound isolator and a broadband sound absorber arranged in the pipeline;
  • the broadband metamaterial degenerate sound absorber includes several acoustic perforated plates perpendicular to the wind direction in the pipeline, and a broadband metamaterial silencer outside the pipeline, or a broadband diversion-type metamaterial silencer inside the pipeline, or a combination of the broadband metamaterial silencer outside the pipeline and the broadband diversion-type metamaterial silencer inside the pipeline.
  • the broadband metamaterial silencer for the ventilation duct is composed of a plurality of resonance units arranged in parallel and independent of each other, the resonance behavior of each resonance unit is single-frequency and corresponds to a frequency in the broadband noise to be reduced, and the resonance unit achieves the sound insulation effect by reflecting sound waves at the resonance frequency and the nearby frequency;
  • the resonance unit is arranged on the side wall of the ventilation duct, and the resonance unit opens to the wall of the ventilation duct, or the resonance unit is arranged on the side wall of the ventilation duct, and the resonance unit opens to the wall of the ventilation duct, and a mesh covering material is arranged at the opening of the resonance unit;
  • the broadband sound absorber arranged outside the duct is composed of a plurality of resonance units arranged in parallel and independent of each other, the resonance behavior of each resonance unit is single-frequency and corresponds to a frequency of the broadband noise to be reduced, and the resonance unit achieves the sound absorption effect by converting the noise energy into heat energy and dissipating it;
  • the resonance unit is arranged on the side wall of the ventilation duct, and the resonance unit opens to the wall of the ventilation duct, or the resonance unit is arranged on the side wall of the ventilation duct, and the resonance unit opens to the wall of the ventilation duct, and a mesh covering material is arranged at the opening of the resonance unit;
  • the broadband sound isolator arranged in the duct is composed of a plurality of resonance units arranged in parallel and independent of each other, the resonance behavior of each resonance unit is single-frequency and corresponds to a frequency in the broadband noise to be reduced, and the resonance unit achieves the sound insulation effect by reflecting sound waves at the resonance frequency and the nearby frequency;
  • the resonance unit is arranged inside the ventilation duct, and the resonance unit opens inside the ventilation duct, or the resonance unit is arranged inside the ventilation duct, and the resonance unit opens inside the ventilation duct, and a mesh covering material is arranged at the opening of the resonance unit;
  • the broadband sound absorber arranged in the duct is composed of a plurality of resonance units arranged in parallel and independent of each other, the resonance behavior of each resonance unit is single-frequency and corresponds to a frequency of the broadband noise to be reduced, and the resonance unit achieves the sound absorption effect by converting the noise energy into heat energy and dissipating it;
  • the resonance unit is arranged inside the ventilation duct, and the resonance unit opens inside the ventilation duct, or the resonance unit is arranged inside the ventilation duct, and the resonance unit opens inside the ventilation duct, and a mesh covering material is arranged at the opening of the resonance unit;
  • each acoustic perforated plate and the broadband metamaterial silencer outside the pipeline and/or the broadband split-flow metamaterial silencer inside the pipeline correspond to a frequency section of the broadband noise to be reduced.
  • the resonance unit includes a hard shell with an opening and air in a cavity of the hard shell.
  • the resonance unit includes but is not limited to a Fabry-Perot (quarter wavelength) resonator, a Helmholtz resonator, and a resonator with a cavity of any shape that can isolate or absorb noise of a certain frequency.
  • the broadband metamaterial silencer for the ventilation duct several resonance units are arranged into a geometric shape with cavities with the same or different cross-sections, and each cavity is bent and folded on a plane or curved surface or in three-dimensional space.
  • the acoustic perforated plate is used to filter impurities in the gas in the ventilation duct.
  • the mesh covering material includes but is not limited to metal mesh, sponge, woven cloth, paper, fiberglass cloth, acoustic perforated plate and any combination of the above six materials.
  • the material of the metamaterial silencer includes but is not limited to metal, plastic, wood, leather, paper, ceramic and any combination of the above six materials.
  • the ventilation duct can be of any shape, including a straight duct, a curved duct, and a duct with a constant or variable cross-sectional shape.
  • the frequency band and effect of the broadband metamaterial silencer are customizable. Since the operating frequency of each resonance unit can be freely adjusted through the design of geometric shape, the frequency distribution ⁇ m of the broadband resonator can be achieved by designing multiple resonance units of different frequencies. In principle, any spectrum impedance can be achieved by a series of resonance units. However, the fact is that a wider effective frequency band and better sound insulation performance mean that a larger volume is required for the design of the resonator. On the other hand, many noise spectra in real life often have strong frequency characteristics. Therefore, it is the most space-saving and cost-saving solution to customize the broadband noise reduction metamaterial according to the characteristics of the specific noise spectrum.
  • the second technical solution provided by the present invention is a design method of a broadband metamaterial silencer for a ventilation duct, comprising the following steps:
  • step 2) According to the data obtained in step 1), the internal structure of the ventilation duct is optimized to reduce the intensity of the noise to be reduced; then the gas flow rate and flow data, as well as the processed spectrum data of the noise to be reduced, are obtained again;
  • a broadband target impedance is set to reduce the noise intensity in the target frequency band of the ventilation duct the most, and then the type of broadband metamaterial silencer and the M resonance units or K acoustic perforated plates and L resonance units in the broadband metamaterial silencer are selected so that the acoustic impedance spectrum of the M resonance units or the K acoustic perforated plates and the L resonance units is the same as the broadband target impedance;
  • the broadband metamaterial silencer is a broadband metamaterial silencer outside the pipeline, or a broadband split-flow metamaterial silencer inside the pipeline;
  • ⁇ is the circular frequency in hertz
  • q is an integer greater than or equal to zero
  • the opening area of the mth resonator be a m
  • the opening length be l
  • the cavity cross-sectional area be A m
  • the cavity length be L
  • the resonant frequency of the mth Helmholtz resonator is By selecting a m /A m so that ⁇ m is evenly distributed in frequency; and then, under the premise of keeping the value of a m /A m unchanged, adjusting A m so that the impedance Z m of different resonators is superimposed, the acoustic impedance spectrum Z( ⁇ ) can be obtained:
  • the unit of Z( ⁇ ) is kg ⁇ m -2 ⁇ s -1 ;
  • Z m i( ⁇ m 2 - ⁇ 2 )/( ⁇ f m ), the unit of Z m is kg ⁇ m -2 ⁇ s -1 ; f m is the resonance intensity, which is proportional to A m and the unit is m2 /kg; the unit of ⁇ m is Hz; ⁇ is the circular frequency and the unit is Hz;
  • ⁇ f is the target frequency band, in Hertz
  • M is the total number of Helmholtz resonators
  • metamaterial silencer is a broadband degenerate absorber
  • ⁇ the broadband resonant frequency in Hz
  • v the kinematic viscosity of air in m2 /s
  • i an imaginary unit
  • J 0/1 the zero (first) order Bessel function
  • a broadband sound isolator or broadband sound absorber or a combination of a broadband sound isolator and a broadband sound absorber is obtained, wherein the noise reduction frequency distribution range is not greater than the noise reduction frequency of the acoustic perforated plate in step 3.2.1);
  • the inner wall of the pipeline, the structure of the broadband metamaterial silencer, and the material and/or structure of the mesh covering material are optimized again to achieve the removal of the target frequency noise.
  • the method for selecting the type of the broadband metamaterial silencer in step 3) is:
  • broadband metamaterial silencers are broadband sound isolators, broadband sound absorbers, and broadband metamaterial degenerate sound absorbers;
  • broadband sound absorber or broadband metamaterial degenerate sound absorber are applicable;
  • a broadband sound isolator or a broadband metamaterial degenerate sound absorber or a combination of a broadband sound absorber and a broadband sound isolator is selected; otherwise, all three are applicable;
  • a broadband isolator or a broadband absorber or a combination of a broadband absorber and a broadband isolator is selected; otherwise, all three are applicable.
  • the third technical solution of the present invention provides a practical application of a broadband metamaterial silencer in a broadband noise reduction scenario of a ventilation duct.
  • the first application of the metamaterial provided by the present invention is:
  • the material of the wearable device is set to be a hard material protruding outward, the hard material is 2 layers or more, and several closed cavities are set between adjacent hard material layers.
  • a closed inner cavity is formed between the innermost hard material layer or a part of the innermost hard material layer and the wearer's skin; the inner cavity and other closed cavities are connected through the channels on each hard material layer, so that the inner cavity and other cavities form a ventilation duct together, the inlet of the ventilation duct is set on the innermost hard material layer or the outermost hard material layer, and the outlet is set on the innermost hard material layer or the outermost hard material layer;
  • the broadband metamaterial silencer is a broadband degenerate sound absorber.
  • the material of the wearable device is set to be a hard material protruding outward, and the hard material has two layers, namely the innermost hard material layer and the outer hard material layer, and two closed cavities are provided between the two hard material layers, namely cavity one and cavity three, and the innermost
  • the inner wall of the hard material layer is provided with a sealing cushion in contact with the wearer's skin, so that an inner cavity is formed between a part of the innermost hard material layer and the wearer's skin, and the inner cavity is cavity 2; channel 1 and channel 2 are provided on the innermost hard material layer of the inner cavity; cavity 1 is connected with cavity 2 through channel 1, and cavity 2 is connected with cavity 3 through channel 2, so that the inner cavity, cavity 1 and cavity 3 together form a ventilation duct, the inlet of the ventilation duct is provided on the innermost hard material layer of cavity 1 and is located outside the inner cavity, and the outlet is provided on the innermost hard material layer of cavity 3
  • a fan is provided at the outlet and/or inlet of the ventilation duct.
  • the frequency of noise reduced by the broadband metamaterial degenerate sound absorber is 800 to 8000 Hz.
  • the resonance unit of the broadband sound absorber arranged outside the duct is a Helmholtz resonator, and the cavity of the Helmholtz resonator is folded back and forth into a maze shape; there are multiple Helmholtz resonators, some of which open on one side wall of the cavity, and the other part of the Helmholtz resonators open on three side walls of the cavity.
  • the second application of the metamaterial provided by the present invention is:
  • An application of a broadband metamaterial silencer for ventilation ducts which is used for noise reduction of ventilation ducts of indoor air exchange equipment;
  • a broadband sound absorber is installed outside the ventilation duct on the side wall of the ventilation duct at the air outlet of the indoor air exchange device.
  • the resonance unit of the broadband sound absorber is a Fabry-Perot resonator.
  • the cavity of the resonance unit is folded back and forth on the same plane.
  • a noise reduction sheet layer is formed by a plurality of parallel and mutually independent resonance units. Each resonance unit in the noise reduction sheet layer opens to the side wall of the ventilation duct.
  • a plurality of noise reduction sheets are stacked and arranged to form the broadband sound absorber.
  • the broadband sound absorber reduces noise at a frequency of 200 to 8000 Hz.
  • the third application of the metamaterial provided by the present invention is:
  • An application of a broadband metamaterial silencer for ventilation ducts which is used to reduce the noise of ventilation ducts of outdoor HVAC equipment;
  • a broadband sound absorber is installed inside the ventilation duct of the outdoor HVAC equipment;
  • the resonance unit of the broadband sound absorber is a Fabry-Perot resonator, the cavity of the resonance unit is folded back and forth on the same plane, and is composed of a plurality of parallel and independent resonance units to form a broadband sound absorber in a rectangular, V-shaped, concave-convex, louvered, array or other shapes, and each resonance unit opens in the ventilation duct;
  • the broadband sound absorber reduces noise at a frequency of 200 to 8000 Hz.
  • the fourth application of the metamaterial provided by the present invention is:
  • a broadband sound isolator is installed outside the duct on the side wall of the ventilation duct at the inlet of the centrifugal fan of the gas water heater.
  • the resonance unit of the broadband sound isolator is a Fabry-Perot resonator.
  • the cavity of the resonance unit is folded back and forth on the same plane, and a broadband sound isolator is formed by a plurality of parallel and independent resonance units, each of which opens on the side wall of the ventilation duct.
  • the broadband sound isolator reduces noise at a frequency of 200 to 4000 Hz.
  • the fifth application of the metamaterial provided by the present invention is:
  • An application of a broadband metamaterial silencer for ventilation ducts which is used for noise reduction of ventilation ducts of power components of equipment (including but not limited to pumps, compressors, motors, etc.);
  • a broadband sound isolator is installed outside the duct on the duct side wall at the outlet and/or inlet position of the ventilation duct of the cabin of the power component of the equipment.
  • the resonance unit of the broadband sound isolator is a Fabry-Perot resonator.
  • the cavity of the resonance unit is folded back and forth on a plane, and a broadband sound isolator is formed by a plurality of parallel and independent resonance units to form a sleeve outside the duct.
  • Each resonance unit opens on the side wall of the ventilation duct.
  • the broadband sound isolator reduces noise at a frequency of 160 to 4000 Hz.
  • the broadband metamaterial silencer of the present invention adopts a broadband metamaterial silencer outside the pipeline, or a broadband shunt-type metamaterial silencer inside the pipeline, or a broadband metamaterial degenerate sound absorber, to effectively achieve the broadband noise reduction effect of the pipeline.
  • the application of the metamaterial silencer of the present invention in wearable devices has great advantages over other traditional technologies. Wearable devices are in close contact with the human body, so ventilation becomes an inevitable requirement. However, the nature of ventilation is naturally contradictory to good noise reduction and sound insulation. In order to reduce the noise of heat dissipation components such as fans in the equipment, or to isolate external noise from the signal collection in the internal equipment, the ventilation and noise reduction characteristics of metamaterials have great advantages. On the other hand, lightness is also extremely important for wearable devices. The customized features of broadband metamaterial technology can achieve maximum acoustic performance with the smallest space and the least material, thereby effectively controlling the overall weight of the device.
  • the metamaterial silencer structure can effectively avoid the absorption of water vapor and various foreign matter generated by human breathing and perspiration, and can be easily disassembled and cleaned directly. This feature can well meet the hygiene requirements of wearable devices.
  • the metamaterial silencer of the present invention has the following advantages in its application in the field of indoor and outdoor HVAC equipment.
  • the function of the metamaterial silencer is based on structural design, does not contain traditional fiber porous materials, and has no potential harm to human health.
  • its internal structure does not have problems such as water accumulation and mold, has a long service life, and can be used in high-standard environments such as clean rooms and dust-free rooms.
  • the working spectrum of the metamaterial silencer can be customized, and the sound absorption or sound insulation capabilities can be concentrated in the main frequency band of the noise, thereby more efficiently reducing the overall noise.
  • the silencer resonance unit can be made of pure metal material to meet the corresponding requirements.
  • the application of the metamaterial silencer of the present invention in household appliances has the following advantages.
  • the resonance unit of the silencer can be made of the same material as the internal connection position, thereby maintaining the integrity of the original structure in appearance.
  • FIG1 is a schematic cross-sectional structure diagram of a broadband split-flow metamaterial silencer in a pipe that is surrounded by a straight-through air duct;
  • FIG2 is a schematic cross-sectional structure diagram of a broadband split-flow metamaterial silencer in a pipe that is surrounded by a V-shaped air duct;
  • FIG3 is a schematic cross-sectional structure diagram of a broadband split-flow metamaterial silencer in a pipe with a concave-convex air duct formed inside the pipe;
  • FIG4 is a schematic cross-sectional structure diagram of a broadband metamaterial silencer outside a pipe in which a mesh covering material is arranged at the opening of a resonance unit;
  • Figure 5 is a schematic diagram of the cross-sectional structure of a broadband metamaterial degenerate sound absorber
  • FIG6 is a graph showing the noise absorption efficiency of the broadband metamaterial degenerate sound absorber of FIG5 ;
  • FIG7 is a schematic diagram of a three-dimensional structure of a broadband sound isolator or broadband sound absorber in which several resonance unit cavities with different cross sections are arranged in a rectangular parallelepiped and each cavity is folded in an L-shape and reciprocating manner on a plane;
  • FIG8 is a schematic diagram of a three-dimensional structure of a broadband sound isolator or broadband sound absorber in which several resonance unit cavities with different cross sections are arranged in a rectangular shape and each cavity is folded in a U shape on a plane;
  • FIG9 is a schematic diagram of a three-dimensional structure of a broadband sound isolator or broadband sound absorber in which several resonance unit cavities with different cross sections are arranged into a rectangular parallelepiped with a round inner portion and a square outer portion, and each cavity is folded in a U shape on a plane;
  • FIG10 is a schematic diagram of a three-dimensional structure of a broadband sound isolator or broadband sound absorber in which several resonance unit cavities with the same cross section are arranged into a cuboid, and each cavity is folded in a U-shape and reciprocating manner in three-dimensional space;
  • FIG11 is a schematic diagram of a cross-sectional structure of a two-dimensional curved pipe with a broadband metamaterial silencer outside the pipe;
  • FIG12 is a schematic diagram of a three-dimensional structure of a cross-section of a three-dimensional curved pipe having a resonance unit opening on the side wall and a broadband metamaterial degenerate sound absorber;
  • FIG13 is a schematic diagram of the three-dimensional structure of the broadband sound absorber outside the pipeline of Example 1;
  • Fig. 14 is a schematic diagram of the planar structure of the noise reduction sheet layer composed of the resonance units in Example 1;
  • FIG15 is a diagram showing the noise reduction effect of the broadband metamaterial silencer of Example 1.
  • Fig. 16 is a partial schematic diagram of the planar structure of the broadband sound absorber in the pipeline of Example 2;
  • FIG17 is a schematic diagram of the three-dimensional structure of a broadband sound absorber in a duct forming a straight-through air duct in a ventilation duct according to Embodiment 2;
  • FIG. 18 is a diagram showing the arrangement of broadband sound absorbers in a duct forming a straight-through air duct in Embodiment 2;
  • FIG19 is a schematic diagram of the front view of the three-dimensional structure of the wearable device and the broadband metamaterial silencer of the ventilation duct in Example 3;
  • FIG20 is a schematic diagram of the rear perspective structure of the wearable device and the broadband metamaterial silencer of the ventilation duct in Example 3;
  • FIG21 is a schematic diagram of the rear view structure of the outer hard material layer of the wearable device in Example 3.
  • FIG22 is a schematic cross-sectional structure diagram of a broadband metamaterial silencer of a wearable device in Example 3;
  • Fig. 23 is a schematic cross-sectional view of the broadband sound isolator of Example 4.
  • Fig. 24 is a transmission loss spectrum diagram of the broadband sound isolator of Example 4.
  • Fig. 25 is a schematic diagram of the three-dimensional structure of the broadband sound isolator of Example 5.
  • FIG. 26 is a transmission loss spectrum diagram of the broadband sound isolator of Example 5.
  • ventilation duct 1. ventilation duct; 2. broadband diversion metamaterial silencer in the duct; 3. broadband metamaterial silencer outside the duct; 4. mesh covering material; 5. opening; 6. acoustic perforated plate; 7. resonance unit cavity; 8. resonance unit; 9. innermost hard material layer; 10. outer hard material layer; 11. broadband sound absorber arranged outside the duct; 12. noise reduction sheet layer; 13. air duct; 901. cavity one; 902. cavity three; 903. cavity two; 904. channel one; 905. channel two; 906. inlet; 907. outlet; 908. sealing cushion; 909. Helmholtz resonator.
  • the invention provides a broadband metamaterial silencer for a ventilation duct, and a design method and application thereof.
  • the main function of the pipe is to guide the airflow to circulate. Therefore, it is best not to cause too much obstruction to the pipe itself.
  • the best way to achieve this requirement is to install sound insulation/sound absorbing materials on the side walls. For a given broadband target impedance, we can design multiple resonance units to achieve its acoustic characteristics.
  • a broadband metamaterial silencer for a ventilation duct 1 wherein the metamaterial silencer is a broadband metamaterial silencer 3 outside the duct, or a broadband split-flow metamaterial silencer 2 inside the duct, or a broadband metamaterial degenerate sound absorber;
  • the broadband metamaterial silencer outside the pipeline includes a broadband sound isolator arranged outside the pipeline, a broadband sound absorber arranged outside the pipeline, or a combination of a broadband sound isolator and a broadband sound absorber arranged outside the pipeline;
  • the diverter-type metamaterial silencer in the pipe includes a broadband sound isolator arranged in the pipe, a broadband sound absorber arranged in the pipe, or a combination of a broadband sound isolator and a broadband sound absorber arranged in the pipe; the diverter-type metamaterial silencer is arranged on one side or both sides of the pipe or surrounds the pipe, and the pipe is enclosed into a straight, V-shaped or concave-convex air duct, as shown in Figures 1 to 3.
  • the broadband metamaterial degenerate sound absorber includes several acoustic perforated plates perpendicular to the wind direction in the pipe, and a broadband metamaterial silencer outside the pipe, or a broadband diversion metamaterial silencer inside the pipe, or a combination of a broadband metamaterial silencer outside the pipe and a broadband diversion metamaterial silencer inside the pipe.
  • the above-mentioned broadband metamaterial silencer for the ventilation duct is composed of a plurality of parallel and independent resonance units, the resonance behavior of each resonance unit is single-frequency and corresponds to a frequency in the broadband noise to be reduced, and the resonance unit achieves the sound insulation effect by reflecting sound waves at the resonance frequency and nearby frequencies (theoretically, a resonance unit with a high quality factor achieves the sound insulation effect by reflecting sound waves at the resonance frequency, but in fact, due to system dissipation in the process of reflecting sound waves by the resonance unit, the quality factor is reduced and the resonance bandwidth is increased.
  • the resonance unit reflects sound waves with a certain bandwidth near the resonance frequency); the resonance unit is arranged on the side wall of the ventilation duct, and the resonance unit opens to the wall of the ventilation duct, or the resonance unit is arranged on the side wall of the ventilation duct, and the resonance unit opens to the wall of the ventilation duct, and a mesh covering material is arranged at the opening of the resonance unit;
  • the broadband sound absorber arranged outside the duct is composed of a plurality of resonance units arranged in parallel and independent of each other, the resonance behavior of each resonance unit is single-frequency and corresponds to a frequency of the broadband noise to be reduced, and the resonance unit achieves the sound absorption effect by converting the noise energy into heat energy and dissipating it;
  • the resonance unit is arranged on the side wall of the ventilation duct, and the resonance unit opens to the wall of the ventilation duct, or the resonance unit is arranged on the side wall of the ventilation duct, and the resonance unit opens to the wall of the ventilation duct, and a mesh covering material is arranged at the opening of the resonance unit;
  • the broadband sound isolator arranged in the duct is composed of a plurality of resonance units arranged in parallel and independent of each other, the resonance behavior of each resonance unit is single-frequency and corresponds to a frequency in the broadband noise to be reduced, and the resonance unit achieves the sound insulation effect by reflecting sound waves at the resonance frequency and nearby frequencies (theoretically, a resonance unit with a high quality factor achieves the sound insulation effect by reflecting sound waves at the resonance frequency, but in fact, since the resonance unit has system dissipation in the process of reflecting sound waves, the quality factor is reduced and the resonance bandwidth is increased, and the resonance unit reflects sound waves with a certain bandwidth near the resonance frequency); the resonance unit is arranged inside the ventilation duct, and the resonance unit opens inside the ventilation duct, or the resonance unit is arranged inside the ventilation duct, and the resonance unit opens inside the ventilation duct, and a mesh covering material is arranged at the opening of the resonance unit;
  • the broadband sound absorber arranged in the duct is composed of a plurality of resonance units arranged in parallel and independent of each other, the resonance behavior of each resonance unit is single-frequency and corresponds to a frequency of the broadband noise to be reduced, and the resonance unit achieves the sound absorption effect by converting the noise energy into heat energy and dissipating it;
  • the resonance unit is arranged inside the ventilation duct, and the resonance unit opens inside the ventilation duct, or the resonance unit is arranged inside the ventilation duct, and the resonance unit opens inside the ventilation duct, and a mesh covering material is arranged at the opening of the resonance unit;
  • a layer of mesh covering material 4 (as shown in FIG. 4 ) is added to the opening 5 of the resonance unit, such as metal mesh, sponge, woven cloth, paper, fiberglass cloth, acoustic perforated plate and combinations thereof.
  • Such covering material can not only effectively alleviate the whistling problem, but also play a physical barrier role: prevent foreign matter from entering the resonance unit and generating additional noise or causing safety problems; prevent dust and other particles from entering and accumulating at the outlet or inside of the resonance unit, thereby affecting the service life of the metamaterial;
  • each acoustic perforated plate and the broadband metamaterial silencer outside the pipe and/or the broadband split-flow metamaterial silencer inside the pipe correspond to a frequency range of broadband noise to be reduced.
  • FIG5 provides a broadband metamaterial degenerate sound absorber composed of two acoustic perforated plates 6 and a broadband metamaterial silencer outside the pipe, and its absorption efficiency is shown in FIG6, which is more than 94% in the frequency range of 130 to 3000 Hz.
  • the resonance unit includes a hard shell with an opening and air in a cavity of the hard shell.
  • the resonance unit includes but is not limited to a Fabry-Perot resonator, a Helmholtz resonator, and a resonator with a cavity of any shape that can isolate or absorb noise of a certain frequency; the acoustic effect of the resonance unit is related to its geometric shape.
  • the ventilation duct can be in any shape.
  • the shape of the duct can also be two-dimensionally curved (as shown in Figures 2, 3, 11), three-dimensionally curved (as shown in Figure 12), etc.
  • the cross-sectional shape of the duct can be constant (as shown in Figure 1) or variable (as shown in Figure 11), and the cross-sectional size of the duct can vary from a few millimeters to dozens of centimeters.
  • Reasonable bending of the duct can increase multiple scattering during sound wave propagation, thereby greatly improving the absorption capacity of the resonator located on the side wall of the duct.
  • the acoustic perforated plate is used to filter impurities in the gas in the ventilation duct.
  • acoustic perforated plates also has some potential advantages beyond acoustics. For example, we can use its mesh structure to achieve a certain filtering function for particulate matter such as dust. Furthermore, we can even use multiple acoustic perforated plate structures to simultaneously achieve multi-level effects of acoustic and material filtration, thereby improving the practicality of the product. Taking Figure 12 as an example, such a sequence of acoustic perforated plates will divide the ventilation duct into different chambers, thereby avoiding mutual contamination between different chambers to a certain extent. Taking the ventilation system of a wearable device as an example, the wearing cavity is frequently exposed to the water vapor of breathing, and the chamber connected to it contains a complex metamaterial structure and electronic system. The acoustic perforated plate structure designed in the ventilation system can effectively avoid the contamination of adjacent cavities by water vapor on the basis of providing acoustic performance.
  • the mesh covering material includes but is not limited to metal mesh, sponge, woven cloth, paper, fiberglass cloth, acoustic perforated plate and any combination of the above six materials.
  • the hard shell includes but is not limited to metal, plastic, wood, leather, paper, ceramic and any combination of the above six materials.
  • the frequency band and effect of the broadband metamaterial silencer are customizable. Since the operating frequency of each resonance unit can be freely adjusted through the design of geometric shape, the frequency distribution ⁇ m of the broadband resonator can be achieved by designing multiple resonance units of different frequencies. In principle, any spectrum impedance can be achieved by a series of resonance units. However, the fact is that a wider effective frequency band and better sound insulation performance mean that a larger volume is required for the design of the resonator. On the other hand, many noise spectra in real life often have strong frequency characteristics. Therefore, it is the most space-saving and cost-saving solution to customize the broadband noise reduction metamaterial according to the characteristics of the specific noise spectrum.
  • the second technical solution provided by the present invention is a design method of a broadband metamaterial silencer for a ventilation duct, comprising the following steps:
  • step 2) According to the data obtained in step 1), the internal structure of the ventilation duct is optimized to reduce the intensity of the noise to be reduced; then the gas flow rate and flow data, as well as the processed spectrum data of the noise to be reduced, are obtained again;
  • a broadband target impedance is set to reduce the noise intensity in the target frequency band of the ventilation duct the most, and then the type of broadband metamaterial silencer and the M resonance units or K acoustic perforated plates and L resonance units in the broadband metamaterial silencer are selected so that the acoustic impedance spectrum of the M resonance units or the K acoustic perforated plates and the L resonance units is the same as the broadband target impedance;
  • the broadband metamaterial silencer is a broadband metamaterial silencer outside the pipeline, or a broadband split-flow metamaterial silencer inside the pipeline;
  • ⁇ is the circular frequency in hertz
  • q is an integer greater than or equal to zero
  • the opening area of the mth resonator be a m
  • the opening length be l
  • the cavity cross-sectional area be A m
  • the cavity length be L
  • the resonant frequency of the mth Helmholtz resonator is By selecting a m /A m so that ⁇ m is evenly distributed in frequency; and then, under the premise of keeping the value of a m /A m unchanged, adjusting A m so that the impedance Z m of different resonators is superimposed, the acoustic impedance spectrum Z( ⁇ ) can be obtained:
  • the unit of Z( ⁇ ) is kg ⁇ m -2 ⁇ s -1 ;
  • Z m i( ⁇ m 2 - ⁇ 2 )/( ⁇ f m ), the unit of Z m is kg ⁇ m -2 ⁇ s -1 ; f m is the resonance intensity proportional to A m , the unit is m2 /kg; ⁇ m is the unit of Hz; ⁇ is the circular frequency, the unit is Hz;
  • ⁇ f is the target frequency band, in Hertz
  • M is the total number of Helmholtz resonators
  • metamaterial silencer is a broadband degenerate absorber
  • ⁇ the broadband resonant frequency in Hz
  • v the kinematic viscosity of air in m2 /s
  • i an imaginary unit
  • J 0/1 the zero (first) order Bessel function
  • a broadband sound isolator or broadband sound absorber or a combination of a broadband sound isolator and a broadband sound absorber is obtained, wherein the noise reduction frequency distribution range is not greater than the noise reduction frequency of the acoustic perforated plate in step 3.2.1);
  • the inner wall of the pipeline, the broadband metamaterial silencer structure, and the mesh covering material and/or structure are optimized again to achieve the removal of target frequency noise.
  • the method for selecting the type of the broadband metamaterial silencer in step 3) is:
  • broadband metamaterial silencers are broadband sound isolators, broadband sound absorbers, and broadband metamaterial degenerate sound absorbers;
  • broadband sound absorber or broadband metamaterial degenerate sound absorber are applicable;
  • a broadband sound isolator or a broadband metamaterial degenerate sound absorber or a combination of a broadband sound absorber and a broadband sound isolator is selected; otherwise, all three are applicable;
  • a broadband isolator or a broadband absorber or a combination of a broadband absorber and a broadband isolator is selected; otherwise, all three are applicable.
  • An indoor air exchange device whose air outlet is circular with a diameter of 160 mm, and whose noise energy is mainly concentrated in the frequency band of 250 to 3000 Hz, and there is a prominent characteristic noise near 290 Hz, and the available space designed for the metamaterial silencer is that the lateral outer dimension does not exceed the device itself, and the internal dimension is not less than the size of its air outlet.
  • the broadband metamaterial silencer of this embodiment is selected as a broadband sound absorber arranged outside the pipe.
  • the resonance unit of the broadband sound absorber is a Fabry-Perot resonator.
  • the opening of the resonance unit is concentrated on the side wall of the air duct of the indoor air exchange equipment.
  • the opening size is 1 cm ⁇ 1 cm.
  • the cavity of the resonance unit is folded in a U shape on the same plane, and 18 parallel and independent resonance units form a noise reduction layer 12 sleeved outside the ventilation duct.
  • noise reduction layers are stacked and arranged to form a broadband sound absorber in the shape of an inner circle and an outer square pipe, as shown in Figures 13 and 14, where the outer size is 245 mm, and the inner circle is kept at 160 mm, which is consistent with the original ventilation duct diameter of the indoor air exchange equipment, and the ventilation flow rate is as high as 325 m3 / hour.
  • the effect comparison is shown in Figure 15.
  • the effect of more than 26 decibels can be achieved, and the final sound power level of the air outlet can be reduced to about 40A weighted decibels.
  • the frequency of noise reduced by the broadband sound absorber of this embodiment is 200 to 8000 Hz.
  • the broadband sound absorber does not contain any porous or fibrous materials, dust particles and other substances harmful to the human body, does not absorb water or mold, has a long service life, and is more suitable for use in fresh air systems such as homes, offices, and businesses that are closely related to human health.
  • the metamaterial broadband silencer designed for this type of industrial noise is a broadband sound absorber designed and installed in the ventilation duct.
  • the resonance unit is a Fabry-Perot resonator.
  • Each broadband sound absorber contains 36 resonance units with cavities folded back and forth on the same plane.
  • the 36 resonance units are arranged in parallel and are independent of each other, forming a flat plate shape with a thickness of 100 mm. As shown in Figure 16, a single reflection absorption coefficient of more than 0.99 can be achieved in the entire target frequency band.
  • the broadband sound absorber of this embodiment can be integrated into various shapes, including rectangular, V-shaped, concave-convex, louvered, array, or other shapes.
  • the rectangular array is shown in FIG1
  • the V-shaped array is shown in FIG2
  • the concave-convex array is shown in FIG3
  • various forms of air ducts 13 are formed in the pipeline.
  • the broadband sound absorber of this embodiment can be customized with different thicknesses (30 cm to 200 cm) and ventilation rates (20% to 70%) according to actual applications, thereby forming a multi-form broadband shunt metamaterial silencer in the pipeline, which can achieve better noise absorption and insertion loss under the premise of providing a greater ventilation rate than the traditional silencer.
  • the frequency of noise reduced by the broadband sound absorber of this embodiment is 200 to 8000 Hz.
  • the application of the metamaterial silencer of the present invention in wearable devices has great advantages over other traditional technologies.
  • wearable devices are in close contact with the human body, so ventilation becomes an inevitable requirement.
  • the nature of ventilation is naturally contradictory to good noise reduction and sound insulation.
  • the ventilation and noise reduction characteristics of the metamaterial silencer have great advantages.
  • lightness is also extremely important for wearable devices.
  • the customized features of broadband metamaterial silencer technology can achieve maximum acoustic performance with the smallest space and the least material, thereby effectively controlling the overall weight of the device.
  • the structure and materials of the broadband metamaterial silencer of the present invention can effectively avoid the absorption of water vapor and various foreign matter in the equipment, and can be easily disassembled and directly cleaned. This feature can well meet the hygiene requirements of wearable devices.
  • the material of the wearable device is set to a hard material protruding outward, and the hard material is two layers, namely the innermost hard material layer 9 and the outer hard material layer 10. There are two closed cavities between the two hard material layers, namely cavity one 901 and cavity three 902.
  • the inner wall of the innermost hard material layer is provided with a sealing cushion 908 in contact with the wearer's skin, so that a part of the innermost hard material layer forms an inner cavity with the wearer's skin, and the inner cavity is cavity two 903; channel one 904 and channel two 905 are provided on the innermost hard material layer of the inner cavity;
  • Cavity 1 is connected to cavity 2 through hole 1, and cavity 2 is connected to cavity 3 through hole 2, so that cavity 2, cavity 1 and cavity 3 together form a ventilation duct, the inlet 906 of the ventilation duct is arranged on the innermost hard material layer of cavity 1 and is located outside the inner cavity, and the outlet 907 of the ventilation duct is arranged on the innermost hard material layer of cavity 3 and is located outside the inner cavity;
  • the broadband metamaterial silencer is a broadband degenerate sound absorber, which is composed of an acoustic perforated plate and a broadband sound absorber 11 arranged outside the duct, wherein the acoustic perforated plate is arranged at
  • the broadband metamaterial silencer of this embodiment is used in the noise reduction of wearable devices, wherein the flow direction of the airflow is: the outside air enters cavity one from the inlet of the ventilation duct located on one side of cavity one, enters cavity two through the small holes of the acoustic perforated plate provided on duct one, and the air becomes humid due to the water vapor discharged by the human body in cavity two.
  • the humid air then enters cavity three through the small holes of the acoustic perforated plate provided on duct two, and finally is discharged through the outlet of the ventilation duct located on one side of cavity three, and a fan can be set at the inlet and/or outlet to increase the air flow in the ventilation duct.
  • the entire ventilation duct especially the air in cavity two, is kept dry due to such circulation, and at the same time, it can also provide the wearer with a more comfortable wearing experience in hot weather. It is worth mentioning that in the design process, we took into account the two requirements of small wind resistance and uniform airflow passing through the surface of cavity two, and made many iterative optimizations using simulation calculation methods, and finally obtained the ventilation duct design of this embodiment.
  • the noise reduction process of the broadband metamaterial silencer of this embodiment is as follows: external noise enters cavity 1 and cavity 3 from the inlet and outlet of the ventilation duct respectively, and is further reduced by the resonance unit Helmholtz resonator of the broadband sound absorber arranged outside the diversion, and then further reduced by the two acoustic perforated plates of channel 1 and channel 2. In addition to most of the absorbed sound wave energy, a small amount of remaining sound energy can enter cavity 2.
  • the broadband sound absorber arranged outside the duct is based on the design concept of the broadband metamaterial silencer mentioned above and the spectrum characteristics of human hearing sensitivity.
  • Several independent Helmholtz resonators 909 are designed on the outside of cavity 1 and cavity 3.
  • Each resonance unit (Helmholtz resonator) is folded into a maze shape, and they are connected to cavity 1 or cavity 3 through openings 5 of different sizes (between 3.4 and 5.7 square millimeters), see Figures 21 and 22. Due to the small opening area, it is difficult for airflow and water vapor to enter the resonator through the opening, but sound can easily enter the resonator through resonance behavior and be absorbed. Therefore, the broadband metamaterial silencer with a nested maze structure can continuously absorb the noise transmitted from cavities one, two, and three without affecting the air circulation, thereby achieving effective noise reduction while ensuring sufficient ventilation.
  • the noise of gas water heaters mainly comes from the small centrifugal fan inside the water heater cabin, where the air outlet is led to the outside through the exhaust duct, and the air inlet duct is exposed on the rear panel of the water heater. Air is usually supplied to the fan through the opening on the rear panel, making the duct the main source of fan noise transmitted indoors. Its main noise energy covers the frequency band of 200 to 3000 Hz, and the internal space is very compact.
  • a corresponding broadband metamaterial silencer is designed at the fan inlet. The design requires that the inlet of the metamaterial silencer remain consistent with the original inlet diameter to reduce the impact on ventilation efficiency, and the overall structure remains within the original lateral area of the fan, without interfering with other original structures.
  • the broadband metamaterial silencer used in this embodiment is a broadband sound isolator outside the pipe, as shown in Figure 23.
  • the resonance unit of the broadband sound isolator is a Fabry-Perot resonator.
  • the cavity of the resonance unit is folded back and forth on the same plane.
  • Ten resonance units arranged in parallel and independent of each other form a broadband sound isolator outside the pipe.
  • the opening of the resonance unit is a rectangular structure of 10 mm ⁇ 20 mm, located on the side wall of the pipe.
  • the overall thickness of the sound isolator is 22 mm, covering important noise frequency bands, forming a broadband sound isolator of 200 to 4000 Hz, and achieving a noise reduction effect of about 8 decibels on a single centrifugal fan, as shown in Figure 24.
  • the broadband metamaterial silencer is designed as a broadband noise reduction metamaterial silencer outside the pipeline, which is installed at the outlet ventilation duct position of the cabin of the power component of the equipment, and the air outlet diameter remains unchanged.
  • the broadband noise reduction metamaterial silencer outside the pipeline is a broadband sound isolator, as shown in FIG25 .
  • the resonance unit of the broadband sound isolator is a Fabry-Perot resonator.
  • the cavity of the resonance unit is folded back and forth on a plane.
  • a broadband sound isolator outside the pipeline is composed of 10 parallel and independent resonance units.
  • the resonance unit is a rectangular cavity with a diameter of 9 mm ⁇ 22 mm.
  • the opening is located on the side wall of the circular air outlet pipe of the power component cabin with a diameter of 41 mm.
  • the overall thickness of the broadband sound isolator is about 24 mm, and the lateral structure is a special-shaped quadrilateral.
  • the broadband sound isolator covers the main broadband noise segment starting from 160 Hz, and the frequency of the noise reduced is 160 to 4000 Hz, with an average transmission loss of more than 6 decibels, as shown in FIG26 . And based on the characteristics of the pure structural absorption noise reduction principle, it will not be affected by factors such as humidity and dust, and can maintain stable noise reduction performance for a long time.

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Abstract

本发明的目的是针对于现有通风管道宽频降噪技术存在的问题，提供了一种通风管道宽频超材料消音器及设计方法和应用，属于噪音处理技术领域。本发明提供的技术方案之一为通风管道宽频超材料消音器，所述超材料消音器为管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器，或者宽频超材料简并吸音器。此外，本发明还提供了上述通风管道宽频超材料消音器的设计方法及其在可穿戴设备中的应用、在室内外暖通设备领域的应用、以及在家电设备中的应用的技术方案。本发明的消音器能够高效地实现管道宽频噪声降噪作用。

Description

通风管道宽频超材料消音器及设计方法和应用 技术领域
本发明属于噪音处理技术领域，特别涉及一种宽频超材料消音器及设计方法和应用。
背景技术
在日常生活和工业生产中，经常会由于各种原因出现热量和物质的聚集。比如在高功率运转的芯片和机器内部会产生热量，在工厂作业过程中会聚集粉尘，在穿戴设备中由于人体呼吸排汗会累积水汽等等。因此通过气流流通带走过量的热量和物质就变得非常重要。
通过管道实现通风是一个常见的方案。其有效率高，设计简单等优势。通过风扇系统的抽和(或)推，目标空间的空气或其他气体会携带着热量和聚集的物质进入管道系统，进而顺着设计的路径导出。
气流在管道里流通的过程中，往往伴随有噪音问题。这类噪音主要有两个来源。一是设备原本的机械或其他内部环境噪音；二是风扇系统额外产生的噪音。这两类噪音都具有频段宽、同时特征频率明显的特点(比如风扇产生的噪音会有和风扇转速相对应的特征频率)。这种特征对于传统的降噪技术提出了巨大挑战。对于传统的多孔声学材料，如海绵、岩面、玻璃纤维等，其工作频段宽，但是无法有效针对特征噪音频段进行定制而加强吸收。而对于传统的声学共振技术，如亥姆霍兹共振腔，虽然其工作频率可以高度定制，但是其带宽却非常窄。因此，如何在通风环境里，同时保证宽频声学效果和针对具体频率的定制能力就成了一个迫切挑战。
发明内容
本发明的目的是针对于现有通风管道宽频降噪技术存在的问题，提供了一种通风管道宽频超材料消音器及设计方法和应用。
一般情况下管道的主要作用是导引气流使其流通循环。因此消音降噪操作最好不要对管道本身产生太多阻碍。而这一要求最好的实现方法就是在侧壁安装隔音/吸音材料。对于一个给定的宽频目标阻抗，我们可以相应设计多个共振单元来 实现其声学特性。
因此，本发明的技术方案之一为，一种通风管道宽频超材料消音器，所述超材料消音器为管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器，或者宽频超材料简并吸音器；
其中：
所述管道外的宽频降噪超材料消音器包括设置在管道外的宽频隔音器，设置在管道外的宽频吸音器，或者设置在管道外的宽频隔音器与宽频吸音器的组合；
所述管道内的宽频分流式超材料消音器包括设置在管道内的宽频隔音器，设置在管道内的宽频吸音器，或者设置在管道内的宽频隔音器与宽频吸音器的组合；
所述宽频超材料简并吸音器包括与管道内风向垂直的数块声学穿孔板，以及管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器，或者管道外的宽频超材料消音器与管道内的宽频分流式超材料消音器的组合。
进一步的，上述通风管道宽频超材料消音器，所述的设置在管道外的宽频隔音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过在共振频率及附近频率反射声波的方式达到隔音效果；共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，或者，共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，并且共振单元的开口处设置网状覆盖材料；
所述的设置在管道外的宽频吸音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过将噪声能量转化为热能耗散掉的方式达到吸音效果；共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，或者，共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，并且共振单元的开口处设置网状覆盖材料；
所述的设置在管道内的宽频隔音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过在共振频率及附近频率反射声波的方式达到隔音效果；共振单元设置于通风管道内部，共振单元开口于通风管道内部，或者，共振单元设置于通风管道内部，共振单元开口于通风管道内部，并且共振单元的开口处设置网状覆盖材料；
所述的设置在管道内的宽频吸音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共 振单元通过将噪声能量转化为热能耗散掉的方式达到吸音效果；共振单元设置于通风管道内部，共振单元开口于通风管道内部，或者，共振单元设置于通风管道内部，共振单元开口于通风管道内部，并且共振单元的开口处设置网状覆盖材料；
所述的宽频超材料简并吸音器，每块声学穿孔板与管道外的宽频超材料消音器和/或管道内的宽频分流式超材料消音器对应待降宽频噪声的一段频率。
进一步的，上述的通风管道宽频超材料消音器，共振单元包括设有开口的硬质壳体和硬质壳体空腔内的空气。
进一步的，上述的通风管道宽频超材料消音器，共振单元包括但不限于能够隔绝或吸收某段频率噪声的法布里-珀罗(四分之一波长)共振器、亥姆霍兹共振器、以及腔体为任意形状的共振器。
进一步的，上述通风管道宽频超材料消音器，数个共振单元以横截面相同或不相同的腔体排列成几何形状，每个腔体均在某个平面或者曲面上或者在三维空间内弯曲和折叠。
进一步的，上述的通风管道宽频超材料消音器，所述声学穿孔板用于过滤通风管道气体中的杂质。
进一步的，上述的通风管道宽频超材料消音器，所述网状覆盖材料包括但不限于金属网、海绵、织布、纸质、玻纤布、声学穿孔板及上述六种材料的任意组合。
进一步的，上述的通风管道宽频超材料消音器，超材料消音器的材质包括但不限于金属、塑料、木料、皮质、纸质、陶瓷及上述六种材料的任意组合。
进一步的，上述的通风管道宽频超材料消音器，通风管道的形态任意，包括直通的、弯曲的、以及横截面形状为恒定的或变化的管道。
宽频超材料消音器产生作用的频段及其效果是可定制化的，由于每一个共振单元的工作频率是可以通过几何形态的设计而自由调整的，宽频共振器的频率分布ω m又可以通过设计多个不同频率的共振单元而实现，原则上任意谱型的阻抗都可以由一系列共振单元实现。然而事实是，更宽的有效频段范围和更好的隔音性能都意味着需要更大的体积用于设计共振器。另一方面，实际生活中的很多噪音频谱往往具有较强的频率特征。因此根据具体噪音频谱的特征去做频谱定制的宽频降噪超材料是最节省空间、节省成本的方案。
基于此，本发明提供的技术方案之二为，一种通风管道宽频超材料消音器的设计方法，包括如下步骤：
1)获取通风管道的内部结构数据，气体流速、流量数据，以及含有噪声强度信息的待降噪声频谱数据；
2)根据步骤1)中获取的数据，对通风管道内部结构进行优化，使待降噪声强度降低；然后再次获取气体流速、流量数据，以及处理后的待降噪声频谱数据；
3)根据处理后的待降噪声频谱数据以及超材料消音器的设计体积上限，设置一个使通风管道目标频段内噪声强度降低最多的宽频目标阻抗，然后选择宽频超材料消音器的类型，及宽频超材料消音器中的M个共振单元或K个声学穿孔板和L个共振单元，使M个共振单元或K个声学穿孔板和L个共振单元的声学阻抗谱型与宽频目标阻抗相同；
具体的，
3.1)当宽频超材料消音器为管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器时；
3.1.1)法布里-珀罗共振器作为共振单元：
对于一个给定的宽频目标阻抗，为了实现作为圆频率ω函数的声学阻抗谱型Z(ω)，设计M个拥有同样横截面积的法布里-珀罗共振器；将这些共振器从长到短依次排列，记第m个共振器的长度为L m，其对应的第一阶共振频率为ω m＝πc/(2L m)；根据ω m的分布，得到单位频率内的模态数目M d；再通过调节每个共振器的长度L m，使得ω m的分布M d满足声学阻抗谱型Z(ω)；
其间约束可用以下关系式(1)表示：
Figure PCTCN2022137550-appb-000001
其中
Figure PCTCN2022137550-appb-000002
φ是所有共振器开口面积和声波入射面总面积之比，ρ＝1.2千克/米 3表示空气密度，c＝343米/秒表示空气中声波的速度，ω是圆频率，单位赫兹，q是大于等于零的整数；
这些不同长度的法布里-珀罗共振器根据需求折叠形成一个紧凑的整体以节省空间，规则的或者特定几何特征均可；
3.1.2)亥姆霍兹共振器作为共振单元：
记第m个共振器的开口面积为a m，开口长度为l，腔体横截面积为A m，腔体长度为L，那么该第m个亥姆霍兹共振器的共振频率为
Figure PCTCN2022137550-appb-000003
通过选取a m/A m使得ω m在频率上均匀分布；再在保持a m/A m数值不变的前提下，调整A m使得不同 共振器的阻抗Z m叠加可以得到声学阻抗谱型Z(ω)：
其间约束关系式(2)为：
Figure PCTCN2022137550-appb-000004
其中，Z(ω)的单位是千克·米 -2·秒 -1；
Z m＝i(ω m 2-ω 2)/(ωf m)，Z m的单位是千克·米 -2·秒 -1；f m为共振强度，正比于A m，单位为米 2/千克；ω m的单位是赫兹；ω是圆频率，单位是赫兹；
Δf为目标频段，单位是赫兹；
M为亥姆霍兹共振器的总数目；
3.2)当超材料消音器为宽频简并吸音器时：
3.2.1)对声学穿孔板的设计
对于一个厚度为τ(单位：米)的硬质穿孔板，如果其上的圆孔孔径是d(单位：米)，孔隙率为φ，其对应的偶极子声学阻抗Z d如公式(3)：
Figure PCTCN2022137550-appb-000005
其中
Figure PCTCN2022137550-appb-000006
ω是宽频共振频率，单位赫兹，ρ＝1.2千克/米 3是空气密度，v是空气的运动粘度，单位米 2/秒，i是虚数单位，而J 0/1是零(一)阶贝塞尔函数；
上式拥有一个渐进展开形式(4)
Figure PCTCN2022137550-appb-000007
在频率不太高，孔径和板厚不太大的情况下，上式(4)中的第二项以及其余高阶项都可以忽略不计，从而穿孔板的声学阻抗可以近似为一个频率无关的常数；
通过设计穿孔板的三个几何参数，使得16vρτ/(d 2φ)与声学阻抗谱型Z(ω)相等；
3.2.2)对宽频隔音器或宽频吸音器或宽频隔音器与宽频吸音器的组合设计
根据步骤3.1)的方法得到降噪频率分布范围不大于步骤3.2.1)中声学穿孔板降噪频率的宽频隔音器或宽频吸音器或宽频隔音器与宽频吸音器的组合；
3.2.3)将这两种声学结构结合在一起之后，得到所需的宽频简并吸收器；
4)根据步骤3)设计的宽频超材料消音器以及其声学阻抗谱型，再次对管道 内壁、宽频超材料消音器结构以及网状覆盖材料材质或/和结构进行优化，以实现对目标频率噪声的去除。
进一步的，上述的通风管道宽频超材料消音器的设计方法，步骤3)中选择宽频超材料消音器的类型的方法为：
其中，宽频超材料消音器的类型为宽频隔音器、宽频吸音器和宽频超材料简并吸音器；
步骤一、
当宽频噪声的反射能量对通风管道进风口端的环境和设备产生不利影响，或这些反射能量会再次反射进入管道中时，选择宽频吸音器或宽频超材料简并吸音器；否则，三者均适用；
步骤二、
当宽频超材料消音器沿着声波传播方向的整体尺寸＜目标频段内噪声声波波长上限，选择宽频隔音器或宽频超材料简并吸音器或宽频吸音器和宽频隔音器的组合；否则，三者均适用；
步骤三、
当宽频超材料消音器对气流影响敏感时，选择宽频隔音器或宽频吸音器或宽频吸音器和宽频隔音器的组合；否则，三者均适用。
基于上述的宽频超材料结构和宽频超材料的设计方法，本发明的技术方案之三为提供了宽频超材料消音器在通风管道宽频降噪场景下的实际应用。
本发明提供的第一个超材料的应用为：
一种通风管道宽频超材料消音器的应用，用于可穿戴装置的降噪；
将可穿戴装置的材料设置成向外凸出的硬质材料，硬质材料为2层或2层以上，相邻硬质材料层间设有数个密闭腔体，最内层硬质材料层或最内层硬质材料层的一部分与佩戴者皮肤之间形成密闭的内腔体；内腔体与其他密闭腔体之间通过各硬质材料层上的孔道连通，使内腔体与其他腔体共同形成通风管道，通风管道的进口设置于最内层硬质材料层或最外层硬质材料层上，出口设置于最内层硬质材料层或最外层硬质材料层上；宽频超材料消音器为宽频简并吸音器。
进一步的，上述通风管道宽频超材料消音器的应用，将可穿戴装置的材料设置成向外凸出的硬质材料，硬质材料为2层，分别为最内层硬质材料层和外层硬质材料层，2层硬质材料层之间设有2个密闭腔体，分别为空腔一和空腔三，最内层 硬质材料层内侧壁设有与佩戴者皮肤相接触的密封软垫，使最内层硬质材料层的一部分与佩戴者皮肤之间形成内腔体，内腔体为空腔二；在内腔体的最内层硬质材料层上设置孔道一和孔道二；空腔一通过孔道一与空腔二连通，空腔二通过孔道二与空腔三连通，使内腔体与空腔一和空腔三共同形成通风管道，通风管道的进口设置于空腔一的最内层硬质材料层上并且位于内腔体外部、出口设置于空腔三的最内层硬质材料层上并且位于内腔体外部；所述宽频超材料消音器为宽频简并吸音器，由声学穿孔板和设置在管道外的宽频吸音器组成，其中，声学穿孔板设置于孔道一和孔道二处，设置在管道外的宽频吸音器分别设置在空腔一和空腔三的侧壁。
进一步的，上述的通风管道宽频超材料消音器的应用，所述通风管道出口处和(或)进口处设置风扇。
进一步的，上述的通风管道宽频超材料消音器的应用，宽频超材料简并吸音器所降噪音的频率为800至8000赫兹。
进一步的，上述的通风管道宽频超材料消音器的应用，设置在管道外的宽频吸音器的共振单元为亥姆霍兹共振器，亥姆霍兹共振器的腔体往复折叠成迷宫状；亥姆霍兹共振器为多个，一部分亥姆霍兹共振器开口于空腔一侧壁，另一部分亥姆霍兹共振器开口于空腔三侧壁。
本发明提供的第二个超材料的应用为：
一种通风管道宽频超材料消音器的应用，用于室内空气交换设备的通风管道降噪；
在位于室内空气交换设备的出风口处的通风管道侧壁安装设置在管道外的宽频吸音器，宽频吸音器的共振单元为法布里-珀罗共振器，共振单元的腔体在同一平面上往复折叠，由数个并列设置并且相互独立的共振单元组成一个套在通风管道外的降噪片层，降噪片层中每个共振单元均开口于通风管道侧壁，数个降噪片层堆叠排列组成宽频吸音器；
所述宽频吸音器所降噪音的频率为200至8000赫兹。
本发明提供的第三个超材料的应用为：
一种通风管道宽频超材料消音器的应用，用于室外暖通设备的通风管道降噪；
在位于室外暖通设备的通风管道内部安装设置在管道内的宽频吸音器；宽频吸音器的共振单元为法布里-珀罗共振器，共振单元的腔体在同一平面上往返折叠，并由数个并列设置并且相互独立的共振单元组成矩形、V字形、凹凸形、百叶形、 阵列形或其他形状的宽频吸音器，每个共振单元均开口于通风管道内；
所述宽频吸音器所降噪音的频率为200至8000赫兹。
本发明提供的第四个超材料的应用为：
一种通风管道宽频超材料消音器的应用，用于燃气热水器的入风管道降噪；
在燃气热水器离心风机入口处的通风管道侧壁安装设置在管道外的宽频隔音器，宽频隔音器的共振单元为法布里-珀罗共振器，共振单元的腔体在同一平面上往复折叠，并由数个并列设置并且相互独立的共振单元组成一个套在管道外的宽频隔音器，每个共振单元均开口于通风管道侧壁；
所述宽频隔音器所降噪音的频率为200至4000赫兹。
本发明提供的第五个超材料的应用为：
一种通风管道宽频超材料消音器的应用，用于设备动力部件(包括但不限于泵、压缩机、马达等)的通风管道降噪；
在设备动力部件的舱体的通风管道出口和/或入口位置的管道侧壁安装设置在管道外的宽频隔音器，宽频隔音器的共振单元为法布里-珀罗共振器，共振单元的腔体在一个平面上往复折叠，并由数个并列设置并且相互独立的共振单元组成一个套在管道外的宽频隔音器，每个共振单元均开口于通风管道侧壁；
所述宽频隔音器所降噪音的频率为160至4000赫兹。
与现有技术相比，本发明的优势在于：
1、本发明的宽频超材料消音器采用管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器，或者宽频超材料简并吸音器，高效地实现管道宽频噪声降噪作用。
2、本发明的超材料消音器在可穿戴设备中的应用较其他传统技术具有极大优势。穿戴设备与人体密切接触，因此透气通风就成了必然需求。但是透气通风的性质与良好的降噪隔音天然矛盾。为了减轻设备中诸如风扇之类的散热部件的噪音，或是隔绝外部噪音对内部设备内的信号采集，超材料的通风降噪特性就有了巨大优势。另一方面，轻便性对穿戴设备也异常重要。而宽频超材料技术的定制化特征可以利用最小的空间，最少的物料达到最大的声学性能，从而有效控制设备整体重量。最后，由于基于塑料、硅胶等材质而不包含传统的多孔声学材料，该超材料消音器结构可以有效避免对人体呼吸和排汗产生的水蒸气和各种异物的吸收，并易于被拆卸直接清洗。该特性可以很好满足穿戴设备对于卫生的要求。
3、本发明的超材料消音器在室内、外暖通设备领域的应用中，存在以下优势。首先，超材料消音器的功能基于结构设计，不含传统纤维多孔材料，对人身健康无潜在危害。其次，其内部结构不存在积水、发霉等问题，使用寿命长久，可用于洁净室、无尘间等高标准环境。此外，针对不同设备的不同噪声特性，超材料消音器工作频谱可定制，将吸音或隔音能力集中在噪声主要频段，从而更高效的降低整体噪声。而对于有耐高温等特殊场景，消音器共振单元可采用纯金属材质，从而满足相应的要求。
4、本发明的超材料消音器在家电设备中的应用，存在以下优势。首先，将结构设计与家电内部狭小的可用空间相结合，并对主要噪声能量频段进行针对性定制，可在几个厘米内的受限空间下实现从200赫兹开始的有效降噪，从而在不影响其它性能的前提下，最高效的降低设备噪声。此外，消音器共振单元可采用与内部连接位置相同的材料，从而在外观上保持原有结构的整体性。
附图说明
图1、管道内围成直通形风道的管道内的宽频分流式超材料消音器剖面结构示意图；
图2、管道内围成V字形风道的管道内的宽频分流式超材料消音器剖面结构示意图；
图3、管道内围成凹凸形风道的管道内的宽频分流式超材料消音器剖面结构示意图；
图4、共振单元的开口处设置网状覆盖材料的管道外的宽频超材料消音器剖面结构示意图；
图5、宽频超材料简并吸音器剖面结构示意图；
图6、图5的宽频超材料简并吸音器对噪声的吸收效率曲线图；
图7、数个横截面不相同的共振单元腔体排列成长方体、每个腔体均在一个平面上以L形和往复方式折叠的宽频隔音器或宽频吸音器的立体结构示意图；
图8、数个横截面不相同的共振单元腔体排列成长方体、每个腔体均在一个平面上以U形折叠的宽频隔音器或宽频吸音器立体结构示意图；
图9、数个横截面不相同的共振单元腔体排列成内圆外方的长方体、每个腔体均在一个平面上以U形折叠的宽频隔音器或宽频吸音器立体结构示意图；
图10、数个横截面相同的共振单元腔体排列成长方体、每个腔体均在三维空间内以U形和往复方式折叠的宽频隔音器或宽频吸音器立体结构示意图；
图11、设有管道外的宽频超材料消音器的二维弯曲管道剖面结构示意图；
图12、侧壁上设有共振单元开口的设置宽频超材料简并吸音器的三维弯曲管道剖面立体结构示意图；
图13、实施例1管道外的宽频吸音器的立体结构示意图；
图14、实施例1共振单元组成的降噪片层的平面结构示意图；
图15、实施例1宽频超材料消音器降噪效果图；
图16、实施例2管道内的宽频吸音器平面结构局部示意图；
图17、实施例2在通风管道内形成直通形风道的管道内的宽频吸音器立体结构示意图；
图18、实施例2形成直通形风道的管道内的宽频吸音器在通风管道内的排布图；
图19、实施例3可穿戴装置与通风管道宽频超材料消音器的正视立体结构示意图；
图20、实施例3可穿戴装置与通风管道宽频超材料消音器的后视立体结构示意图；
图21、实施例3可穿戴装置的外层硬质材料层后视结构示意图；
图22、实施例3可穿戴装置的宽频超材料消音器剖面结构示意图；
图23、实施例4宽频隔音器的剖面结构示意图；
图24、实施例4宽频隔音器的传递损失频谱图；
图25、实施例5宽频隔音器的立体结构示意图；
图26、实施例5宽频隔音器的传递损失频谱图。
其中，1、通风管道；2、管道内的宽频分流式超材料消音器；3、管道外的宽频超材料消音器；4、网状覆盖材料；5、开口；6、声学穿孔板；7、共振单元腔体；8、共振单元；9、最内层硬质材料层；10、外层硬质材料层；11、设置在管道外的宽频吸音器；12、降噪片层；13、风道；901、空腔一；902、空腔三；903、空腔二；904、孔道一；905、孔道二；906、进口；907、出口；908、密封软垫；909、亥姆霍兹共振器。
具体实施方式
本发明提供了一种通风管道宽频超材料消音器及设计方法和应用。
一般情况下管道的主要作用是导引气流使其流通循环。因此消音降噪操作最好不要对管道本身产生太多阻碍。而这一要求最好的实现方法就是在侧壁安装隔音/吸音材料。对于一个给定的宽频目标阻抗，我们可以相应设计多个共振单元来实现其声学特性。
一种通风管道1宽频超材料消音器，所述超材料消音器为管道外的宽频超材料消音器3，或者管道内的宽频分流式超材料消音器2，或者宽频超材料简并吸音器；
其中：
所述管道外的宽频超材料消音器包括设置在管道外的宽频隔音器，设置在管道外的宽频吸音器，或者设置在管道外的宽频隔音器与宽频吸音器的组合；
当管道口径比较大的时候，例如暖通空调隔音器，除了在管道侧壁安装超材料之外，通常还会在管道内部增加一些分流式超材料结构以增加超材料共振单元的设计空间和开口面积，同时有效提高消音器工作的截止频率。管道内的分流式超材料消音器包括设置在管道内的宽频隔音器，设置在管道内的宽频吸音器，或者设置在管道内的宽频隔音器与宽频吸音器的组合；分流式超材料消音器设置在管道内部的单侧或双侧或围绕管道，并将管道内围成直通的、V字的或凹凸的风道，如图1～3所示。
是否可以在远小于波长的小尺度实现对声音的高吸收，这一点在实际应用中有着重要的意义。一方面，很多实际场景在各方面的限制下未必有很大的管道侧壁面积以供开口连接超材料结构。另一方面，尽量减小共振结构的开口面积也可以减弱对气流产生的非线性影响。因此，可以采用宽频简并吸音器作为消音器。宽频超材料简并吸音器包括与管道内风向垂直的数块声学穿孔板，以及管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器，或者管道外的宽频超材料消音器与管道内的宽频分流式超材料消音器的组合。
进一步的，上述的通风管道宽频超材料消音器，所述的设置在管道外的宽频隔音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过在共振频率及附近频率反射声波的方式达到隔音效果(理论上，拥有高品质因子的共振单元通过反射共振 频率的声波达到隔音效果，但由于实际上共振单元在反射声波的过程中存在系统耗散情况，导致品质因子降低，共振带宽增加，共振单元反射的是共振频率附近有一定带宽的声波)；共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，或者，共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，并且共振单元的开口处设置网状覆盖材料；
所述的设置在管道外的宽频吸音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过将噪声能量转化为热能耗散掉的方式达到吸音效果；共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，或者，共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，并且共振单元的开口处设置网状覆盖材料；
所述的设置在管道内的宽频隔音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过在共振频率及附近频率反射声波的方式达到隔音效果(理论上，拥有高品质因子的共振单元通过反射共振频率的声波达到隔音效果，但由于实际上共振单元在反射声波的过程中存在系统耗散情况，导致品质因子降低，共振带宽增加，共振单元反射的是共振频率附近有一定带宽的声波)；共振单元设置于通风管道内部，共振单元开口于通风管道内部，或者，共振单元设置于通风管道内部，共振单元开口于通风管道内部，并且共振单元的开口处设置网状覆盖材料；
所述的设置在管道内的宽频吸音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过将噪声能量转化为热能耗散掉的方式达到吸音效果；共振单元设置于通风管道内部，共振单元开口于通风管道内部，或者，共振单元设置于通风管道内部，共振单元开口于通风管道内部，并且共振单元的开口处设置网状覆盖材料；
在共振单元的开口5处增加一层网状覆盖材料4(如图4所示)，例如金属网、海绵、织布、纸质、玻纤布、声学穿孔板及其组合形式等等。此类覆盖物不仅能有效缓解哨声问题，还可以起到物理阻隔作用：防止异物进入共振单元而产生额外噪音或者引发安全问题；防止灰尘等颗粒物进入并堆积在共振单元出口或内部，进而影响超材料使用寿命；
所述的宽频超材料简并吸音器，每块声学穿孔板与管道外的宽频超材料消音器和/或管道内的宽频分流式超材料消音器对应待降宽频噪声的一段频率。图5提供 了一种由2块声学穿孔板6和管道外的宽频超材料消音器组成的宽频超材料简并吸音器，其吸收效率如图6所示，在130到3000赫兹的频率范围内均超过94％。
进一步的，上述的通风管道宽频超材料消音器，共振单元包括设有开口的硬质壳体和硬质壳体空腔内的空气。
进一步的，上述的通风管道宽频超材料消音器，共振单元包括但不限于能够隔绝或吸收某段频率噪声的法布里-珀罗共振器、亥姆霍兹共振器、以及腔体为任意形状的共振器；共振单元的声学效果与其几何形态相关。
进一步的，上述的通风管道宽频超材料消音器，宽频隔音器或宽频吸音器的数个共振单元以横截面相同或不相同的腔体排列成几何形状，每个腔体均在某个平面或者曲面上弯曲和折叠，如图7～9，或者在三维空间内弯曲和折叠，如图10。整个宽频共振器的形状可以是规则的，也可以是不规则，可根据具体应用场景对几何形状的要求和限制进行定制化设计，如图7～10。
进一步的，上述的通风管道宽频超材料消音器，通风管道的形态任意，除了直通(如图1、4～5)之外，管道的形态也可以是二维弯曲的(如图2、3、11)、三维弯曲的(如图12)等等。沿着声波传播方向，管道的横截形状可以是恒定的(如图1)，也可以是变化的(如图11)，管道截面尺寸大小可以从几个毫米到几十个厘米不等。管道合理的弯折可以增加声波传播过程中的多重散射，从而大大提升位于管道侧壁的共振器的吸收能力。
进一步的，上述的通风管道宽频超材料消音器，所述声学穿孔板用于过滤通风管道气体中的杂质。
声学穿孔板的引入也有一些声学之外的潜在优点。比如我们可以利用其网孔结构实现对尘土等颗粒物质一定的过滤功能。进一步的，我们甚至可以使用多个声学穿孔板结构同时实现声学和物质过滤的多级效果，从而提高产品的实用性。以图12为例，这样的声学穿孔板序列会将通风管道划分为不同的腔室，从而在一定程度上避免不同腔室之间的相互污染。以某穿戴设备的通风系统为例，佩戴腔体频繁暴露于呼吸的水汽中，而与其相连的腔室则包含有复杂的超材料结构和电子系统，通风系统中设计的声学穿孔板结构在提供声学效能的基础上，可以有效避免水汽对于相邻腔体的污染。
进一步的，上述的通风管道宽频超材料消音器，所述网状覆盖材料包括但不限于金属网、海绵、织布、纸质、玻纤布、声学穿孔板及上述六种材料的任意组合。
进一步的，上述的通风管道宽频超材料消音器，所述硬质壳体包括但不限于金属、塑料、木料、皮质、纸质、陶瓷及上述六种材料的任意组合。
宽频超材料消音器产生作用的频段及其效果是可定制化的，由于每一个共振单元的工作频率是可以通过几何形态的设计而自由调整的，宽频共振器的频率分布ω m又可以通过设计多个不同频率的共振单元而实现，原则上任意谱型的阻抗都可以由一系列共振单元实现。然而事实是，更宽的有效频段范围和更好的隔音性能都意味着需要更大的体积用于设计共振器。另一方面，实际生活中的很多噪音频谱往往具有较强的频率特征。因此根据具体噪音频谱的特征去做频谱定制的宽频降噪超材料是最节省空间、节省成本的方案。
基于此，本发明提供的技术方案之二为，一种通风管道宽频超材料消音器的设计方法，包括如下步骤：：
1)获取通风管道的内部结构数据，气体流速、流量数据，以及含有噪声强度信息的待降噪声频谱数据；
2)根据步骤1)中获取的数据，对通风管道内部结构进行优化，使待降噪声强度降低；然后再次获取气体流速、流量数据，以及处理后的待降噪声频谱数据；
3)根据处理后的待降噪声频谱数据以及超材料消音器的设计体积上限，设置一个使通风管道目标频段内噪声强度降低最多的宽频目标阻抗，然后选择宽频超材料消音器的类型，及宽频超材料消音器中的M个共振单元或K个声学穿孔板和L个共振单元，使M个共振单元或K个声学穿孔板和L个共振单元的声学阻抗谱型与宽频目标阻抗相同；
具体的，
3.1)当宽频超材料消音器为管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器时；
3.1.1)法布里-珀罗共振器作为共振单元：
对于一个给定的宽频目标阻抗，为了实现作为圆频率ω函数的声学阻抗谱型Z(ω)，设计M个拥有同样横截面积的法布里-珀罗共振器；将这些共振器从长到短依次排列，记第m个共振器的长度为L m，其对应的第一阶共振频率为ω m＝πc/(2L m)；根据ω m的分布，得到单位频率内的模态数目M d；再通过调节每个共振器的长度L m，使得ω m的分布M d满足声学阻抗谱型Z(ω)；
其间约束可用以下关系式(1)表示：
Figure PCTCN2022137550-appb-000008
其中
Figure PCTCN2022137550-appb-000009
φ是所有共振器开口面积和声波入射面总面积之比，ρ＝1.2千克/米 3表示空气密度，c＝343米/秒表示空气中声波的速度，ω是圆频率，单位赫兹，q是大于等于零的整数；
这些不同长度的法布里-珀罗共振器根据需求折叠形成一个紧凑的整体以节省空间，规则的或者特定几何特征均可；
3.1.2)亥姆霍兹共振器作为共振单元：
记第m个共振器的开口面积为a m，开口长度为l，腔体横截面积为A m，腔体长度为L，那么该第m个亥姆霍兹共振器的共振频率为
Figure PCTCN2022137550-appb-000010
通过选取a m/A m使得ω m在频率上均匀分布；再在保持a m/A m数值不变的前提下，调整A m使得不同共振器的阻抗Z m叠加可以得到声学阻抗谱型Z(ω)：
其间约束关系式(2)为：
Figure PCTCN2022137550-appb-000011
其中，Z(ω)的单位是千克·米 -2·秒 -1；
Z m＝i(ω m 2-ω 2)/(ωf m)，Z m的单位是千克·米 -2·秒 -1；f m为共振强度正比于A m，单位为米 2/千克；ω m的单位是赫兹；ω是圆频率，单位是赫兹；
Δf为目标频段，单位是赫兹；
M为亥姆霍兹共振器的总数目；
3.2)当超材料消音器为宽频简并吸音器时：
3.2.1)对声学穿孔板的设计
对于一个厚度为τ(单位：米)的硬质穿孔板，如果其上的圆孔孔径是d(单位：米)，孔隙率为φ，其对应的偶极子声学阻抗Z d如公式(3)：
Figure PCTCN2022137550-appb-000012
其中
Figure PCTCN2022137550-appb-000013
ω是宽频共振频率，单位赫兹，ρ＝1.2千克/米 3是空气密度，v是空气的运动粘度，单位米 2/秒，i是虚数单位，而J 0/1是零(一)阶贝塞尔函数；
上式拥有一个渐进展开形式(4)
Figure PCTCN2022137550-appb-000014
在频率不太高，孔径和板厚不太大的情况下，上式(4)中的第二项以及其余高阶项都可以忽略不计，从而穿孔板的声学阻抗可以近似为一个频率无关的常数；
通过设计穿孔板的三个几何参数，使得16vρτ/(d 2φ)与声学阻抗谱型Z(ω)相等；
3.2.2)对宽频隔音器或宽频吸音器或宽频隔音器与宽频吸音器的组合设计
根据步骤3.1)的方法得到降噪频率分布范围不大于步骤3.2.1)中声学穿孔板降噪频率的宽频隔音器或宽频吸音器或宽频隔音器与宽频吸音器的组合；
3.2.3)将这两种声学结构结合在一起之后，得到所需的宽频简并吸收器；
宽频超材料消音器在实际使用中，如果对降噪要求不是特别高，穿孔板具体参数可以以吸收性能为代价做一定程度的放宽。另一方面，这样穿孔板在管道内的存在也势必会带来一定风阻，实际应用中也应当根据气流的需求做平衡优化；
4)根据步骤3)设计的宽频超材料消音器以及其声学阻抗谱型，再次对管道内壁、宽频超材料消音器结构以及网状覆盖材料材质和/或结构进行优化，以实现对目标频率噪声的去除。
进一步的，上述通风管道宽频超材料消音器的设计方法，步骤3)中选择宽频超材料消音器的类型的方法为：
其中，宽频超材料消音器的类型为宽频隔音器、宽频吸音器和宽频超材料简并吸音器；
步骤1
当宽频噪声的反射能量对通风管道进风口端的环境和设备产生不利影响，或这些反射能量会再次反射进入管道中时，选择宽频吸音器或宽频超材料简并吸音器；否则，三者均适用；
步骤2
当宽频超材料消音器沿着声波传播方向的整体尺寸＜目标频段内声波波长上限，选择宽频隔音器或宽频超材料简并吸音器或宽频吸音器和宽频隔音器的组合；否则，三者均适用；
步骤3
当宽频超材料消音器对气流影响敏感时，选择宽频隔音器或宽频吸音器或宽频吸音器和宽频隔音器的组合；否则，三者均适用。
以下基于本发明技术方案的宽频超材料消音器和设计方法所做具体应用。
实施例1
宽频超材料消音器在室内空气交换设备中降噪的应用。
一室内空气交换设备，其出风口为直径160毫米的圆形，且其噪声能量主要集中在250至3000赫兹频段，并且在290赫兹附近有一突出的特征噪声，超材料消音器设计的可用空间为横向外尺寸不超过设备本身，内部不小于其出风口尺寸。
通过频谱分析以及定制，本实施例的宽频超材料消音器选择为设置于管道外的宽频吸音器，宽频吸音器的共振单元为法布里-珀罗共振器，将共振单元开口集中设计在室内空气交换设备风管的侧壁上，开口尺寸为1厘米×1厘米，共振单元的腔体在同一平面以U形折叠，并由18个并列设置并且相互独立的共振单元组成一个套在通风管道外的降噪片层12，数个降噪片层堆叠排列组成内圆外方管道形状的宽频吸音器，如图13～14所示，其中外部尺寸为245毫米，内部的圆形保持同室内空气交换设备原始通风管直径一致的160毫米，通风流量高达325米 3/小时。我们将宽频吸音器的吸收能力集中在重要的噪声频段，即250赫兹往上，从而在半米长度内，实现了13分贝的整体降噪量，比原有一米传统降噪管(玻璃纤维)的9分贝降噪量效果更优，效果对比如图15所示。全长1米的情况下能实现超过26分贝的效果，将最终出风口声功率级别降低至约40A种加权分贝。本实施例宽频吸音器所降噪音的频率为200至8000赫兹。同时，该宽频吸音器内不含任何多孔或纤维材料，无粉尘颗粒等对人体有害物质，不吸水不发霉、使用寿命长久，更适合在与人体健康紧密相关的居家、办公、商用等新风系统中应用。
实施例2
宽频超材料消音器在大型室外暖通设备降噪中的应用。
大型室外暖通设备，噪声来源于顶部的风扇组以及下方的压缩机等设备，主要覆盖200至4000赫兹宽频段，低频段占据主要能量，且设备整体对通风散热要求较高。针对此类工业噪声设计的超材料宽频消音器，为在通风管道内设计的设置在管道内的宽频吸音器，共振单元为法布里-珀罗共振器，每个宽频吸音器包含36个在同一平面上腔体往返折叠的共振单元，36根共振单元并列设置并且相互独立， 形成厚度100毫米的平板形状，如图16所示，在全目标频段可以实现超过0.99的单次反射吸收系数。
本实施例的宽频吸音器可以集成各种形状，包括矩形、V字形、凹凸形、百叶形、阵列形、或其他形状，矩形阵列如图1所示，V字形阵列如图2所示，凹凸形阵列如图3所示，并在通过管道内形成各类形态的风道13。并且，本实施例的宽频吸音器根据实际应用可以定制不同厚度(30厘米～200厘米)以及通风率(20％～70％)等参数，从而形成多形态的管道内宽频分流式超材料消音器，可在比传统消音器提供更大通风率的前提下，实现更好的噪声吸收以及插入损失。本实施例宽频吸音器所降噪音的频率为200至8000赫兹。
实施例3
宽频超材料消音器在可穿戴设备降噪中的应用。
本发明的超材料消音器在可穿戴设备中的应用较其他传统技术具有极大优势。一方面，可穿戴设备与人体密切接触，因此透气通风就成了必然需求。但是透气通风的性质与良好的降噪隔音天然矛盾。为了减轻设备中诸如风扇之类的散热部件的噪音，或是隔绝外部噪音对设备内部的信号采集，超材料消音器的通风降噪特性就有了巨大优势。另一方面，轻便性对穿戴设备也异常重要。而宽频超材料消音器技术的定制化特征可以利用最小的空间，最少的物料达到最大的声学性能，从而有效控制设备整体重量。最后，由于基于塑料、硅胶等材质而不包含传统的多孔声学材料，本发明宽频超材料消音器的结构和材料可以有效避免对设备内的水蒸汽和各种异物的吸收，并易于被拆卸直接清洗。该特性可以很好满足穿戴设备对于卫生的要求。
可穿戴设备对部件的质量和体积大小敏感，又有较大的通风需求甚至需要安装风扇来除去人体呼吸和排汗所产生的水蒸汽，这便要求宽频超材料消音器可以在尽可能小的体积，尽可能大的通风的前提下，实现尽可能好的降噪效果，这对传统设计消音器的思路来说是极具挑战的。在本方案中，如图19～22所示，将可穿戴装置的材料设置成向外凸出的硬质材料，硬质材料为2层，分别为最内层硬质材料层9和外层硬质材料层10，2层硬质材料层之间设有2个密闭腔体，分别为空腔一901和空腔三902，位于最内层硬质材料层内侧壁设有与佩戴者皮肤相接触的密封软垫908，使最内层硬质材料层的一部分与佩戴者皮肤之间形成内腔体，内腔体为空腔二903；在内腔体的最内层硬质材料层上设置孔道一904和孔道二905； 空腔一通过孔道一与空腔二连通，空腔二通过孔道二与空腔三连通，使空腔二与空腔一和空腔三共同形成通风管道，通风管道的进口906设置于空腔一的最内层硬质材料层上并且位于内腔体外部、通风管道的出口907设置于空腔三的最内层硬质材料层上并且位于内腔体外部；所述宽频超材料消音器为宽频简并吸音器，由声学穿孔板和设置在管道外的宽频吸音器11组成，其中，声学穿孔板设置于孔道一和孔道二处，设置在管道外的宽频吸音器分别设置在空腔一和空腔三的侧壁。我们首次设计了嵌套型迷宫结构的亥姆霍兹共振器作为共振单元，共振单元设计成同迷宫般形状弯折缠绕的腔体。
本实施例的宽频超材料消音器在可穿戴设备降噪中的应用，其中，气流的流向为：外界的空气从位于空腔一一侧的通风管道的进口进入空腔一，通过孔道一上设有的声学穿孔板的小孔进入空腔二，空气因携带了空腔二中人体排出的水蒸汽而变得潮湿，这些潮湿的空气再通过孔道二上设有的声学穿孔板的小孔进入空腔三，最后通过位于空腔三一侧的通风管道的出口排出，并且在进口和/或出口处可以设置风扇以增加通风管道内的空气流动。整个通风管道尤其是空腔二中的空气因这样的循环而保持干燥，同时也能在炎热的天气中让佩戴者有更舒适的佩戴体验。值得一提的是，在设计过程中我们兼顾了小风阻和气流均匀地经过空腔二表面这两个要求，用模拟计算的方法做了很多次迭代优化，最终得到了本实施例的通风管道设计。
本实施例的宽频超材料消音器的降噪的过程为：外部噪音分别从通风管道的进口和出口进入空腔一和空腔三，被设置在改道外的宽频吸音器的共振单元亥姆霍兹共振器进一步降噪，再通过孔道一和孔道二的两处声学穿孔板进一步降噪后，除了大部分被吸收的声波能量，剩余少量的声音能量能进入孔腔二。其中，设置在管道外的宽频吸音器是根据上文提到的宽频超材料消音器设计思路和人耳听觉敏感度频谱特征，在空腔一和空腔三的外侧设计了数个相互独立的亥姆霍兹共振器909，每个共振单元(亥姆霍兹共振器)折叠成迷宫状，它们分别通过面积大小不一的开口5(3.4到5.7平方毫米之间)与空腔一或者空腔三相连通，见图21和22。由于开口面积小，气流和水蒸汽很难通过开口进入共振器，但是声音却可以通过共振行为轻松进入共振器并被吸收。因此，该嵌套型迷宫结构的宽频超材料消音器可以不断吸收由空腔一、二、三传播而来的噪音却不影响空气流通，进而在保障足够通风量的前提下实现了有效降噪。
我们根据ISO 717-1 2013的标准，在一个3米×3米×3米的消音室中测试了本实施例的宽频消音器(10个样品)的插入损失，测试结果显示该部件在消音器设计频段，即800至8000赫兹，其插入损失远高于相同形状的无超材料对照试验组。该部件在白噪音测试下的等效插入损失为25.3±0.3A种加权分贝，在人声测试下为21.6±0.3A种加权分贝。而无超材料结构设计的对照组在相同条件下的测试结果分别为17.4A种加权分贝(白噪音)和10.3A种加权分贝(人声)。
我们同时测试了该部件管道设计的通风性能，测试结果显示该通风系统能非常有效地起到去除湿气的作用。若以相对湿度进行描述，即
Figure PCTCN2022137550-appb-000015
Figure PCTCN2022137550-appb-000016
其中RH 0为环境相对湿度，t 0是开启风扇的时间，测得一次除水汽的平均寿命因子a＝44.3±4.1秒。
实施例4
宽频超材料消音器在热水器风机降噪中的应用。
燃气热水器的噪声，主要来源于热水器舱体内部的小型离心风机，其中出风口通过排气管道引向室外，而入风口的风道则暴露在热水器后面板上，通常通过该后端面板上的开口向风机送风，从而使得该风道成为向室内传播风扇噪声的主要来源，其主要噪声能量覆盖200至3000赫兹频段，且内部空间非常紧凑。通过空间与频谱分析，在风机入风口处设计对应的宽频超材料消音器，设计要求超材料消音器入风口保持与原有入风口直径一致，从而减小对通风效率的影响，且整体结构保持在风机的原有横向区域内，不对其它原有结构造成干扰。本实施例采用的宽频超材料消音器为管道外的宽频隔音器，如图23所示，宽频隔音器的共振单元为法布里-珀罗共振器，共振单元的腔体在同一平面上往复折叠，由并列设置并且相互独立的10根共振单元组成一个管道外的宽频隔音器，共振单元开口为10毫米×20毫米的矩形结构，位于管道侧壁，隔音器整体厚度22毫米，覆盖重要的噪声频段，形成200至4000赫兹的宽频隔音器，在单离心风机上实现约8分贝的降噪效果，如图24所示。
实施例5
宽频超材料消音器在设备动力部件(包括但不限于泵、压缩机、马达等)的通风管道中的应用。
标准情况下，部分设备的动力部件(包括但不限于泵、压缩机、马达等)存在 显著噪音问题，而动力部件因为有散热需求，无法对其进行完全封闭式处理，从而使动力部件成为室内传播噪声的主要来源，从而需要在保持通风的情况下进行有效降噪。传统多孔材料在空间限制下无法对低频形成高效降噪，且容易吸水受潮，不能作为有效降噪手段。本实施例将宽频超材料消音器设计为管道外的宽频降噪超材料消音器，安装在设备动力部件的舱体的出口通风管道位置，且保持出风口径不变。所述管道外的宽频降噪超材料消音器为宽频隔音器，如图25所示，宽频隔音器的共振单元为法布里-珀罗共振器，共振单元的腔体在一个平面上往复折叠，由10根并列设置并且相互独立的共振单元组成一个管道外的宽频隔音器，共振单元为口径9毫米×22毫米的矩形腔体，开口位于直径41毫米的动力部件舱体的圆形出风口管侧壁，宽频隔音器整体厚度约24毫米，横向结构为一异形四边形。该宽频隔音器覆盖从160赫兹起始的主要宽频噪声段，所降噪音的频率为160至4000赫兹，平均传递损失超过6分贝，如图26所示。且基于纯结构吸收降噪原理的特性，使得其不会受到湿度、灰尘等因素的影响，能长久保持稳定的降噪性能。

Claims (20)

  1. 一种通风管道宽频超材料消音器，其特征在于，所述超材料消音器为管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器，或者宽频超材料简并吸音器；
    其中：
    所述管道外的宽频降噪超材料消音器包括设置在管道外的宽频隔音器，设置在管道外的宽频吸音器，或者设置在管道外的宽频隔音器与宽频吸音器的组合；
    所述管道内的宽频分流式超材料消音器包括设置在管道内的宽频隔音器，设置在管道内的宽频吸音器，或者设置在管道内的宽频隔音器与宽频吸音器的组合；
    所述宽频超材料简并吸音器包括与管道内风向垂直的数块声学穿孔板，以及管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器，或者管道外的宽频超材料消音器与管道内的宽频分流式超材料消音器的组合。
  2. 根据权利要求1所述的通风管道宽频超材料消音器，其特征在于，
    所述的设置在管道外的宽频隔音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过在共振频率及附近频率反射声波的方式达到隔音效果；共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，或者，共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，并且共振单元的开口处设置网状覆盖材料；
    所述的设置在管道外的宽频吸音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过将噪声能量转化为热能耗散掉的方式达到吸音效果；共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，或者，共振单元设置于通风管道的侧壁，共振单元开口于通风管道管壁，并且共振单元的开口处设置网状覆盖材料；
    所述的设置在管道内的宽频隔音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共振单元通过在共振频率及附近频率反射声波的方式达到隔音效果；共振单元设置于通风管道内部，共振单元开口于通风管道内部，或者，共振单元设置于通风管道内部，共振单元开口于通风管道内部，并且共振单元的开口处设置网状覆盖材料；
    所述的设置在管道内的宽频吸音器，由数个并列设置并且相互独立的共振单元组成，每个共振单元的共振行为是单频的并对应待降宽频噪声中的一段频率，共 振单元通过将噪声能量转化为热能耗散掉的方式达到吸音效果；共振单元设置于通风管道内部，共振单元开口于通风管道内部，或者，共振单元设置于通风管道内部，共振单元开口于通风管道内部，并且共振单元的开口处设置网状覆盖材料；
    所述的宽频超材料简并吸音器，每块声学穿孔板与管道外的宽频超材料消音器和/或管道内的宽频分流式超材料消音器对应待降宽频噪声的一段频率。
  3. 根据权利要求2所述的通风管道宽频超材料消音器，其特征在于，共振单元包括设有开口的硬质壳体和硬质壳体空腔内的空气。
  4. 根据权利要求2或3所述的通风管道宽频超材料消音器，其特征在于，共振单元包括但不限于能够隔绝或吸收某段频率噪声的法布里-珀罗共振器、亥姆霍兹共振器、以及腔体为任意形状的共振器。
  5. 根据权利要求2或3或4所述的通风管道宽频超材料消音器，其特征在于，数个共振单元以横截面相同或不相同的腔体排列成几何形状，每个腔体均在某个平面或者曲面上或者在三维空间内弯曲和折叠。
  6. 根据权利要求1或2所述的通风管道宽频超材料消音器，其特征在于，所述声学穿孔板用于过滤通风管道气体中的杂质。
  7. 根据权利要求2所述的通风管道宽频降噪超材料，其特征在于，所述网状覆盖材料包括但不限于金属网、海绵、织布、纸质、玻纤布、声学穿孔板及上述六种材料的任意组合。
  8. 根据权利要求1～6任意一项所述的通风管道宽频超材料消音器，其特征在于，超材料消音器的材质包括但不限于金属、塑料、木料、皮质、纸质、陶瓷及上述六种材料的任意组合。
  9. 根据权利要求1～4任意一项所述的通风管道宽频超材料消音器，其特征在于，通风管道的形态任意，包括直通的、弯曲的、以及横截面形状为恒定的或变化的管道。
  10. 一种通风管道宽频超材料消音器的设计方法，其特征在于，包括如下步骤：
    1)获取通风管道的内部结构数据，气体流速、流量数据，以及含有噪声强度信息的待降噪声频谱数据；
    2)根据步骤1)中获取的数据，对通风管道内部结构进行优化，使待降噪声强度降低；然后再次获取气体流速、流量数据，以及处理后的待降噪声频谱数据；
    3)根据处理后的待降噪声频谱数据以及超材料消音器的设计体积上限，设置 一个使通风管道目标频段内噪声强度降低最多的宽频目标阻抗，然后选择宽频超材料消音器的类型，及宽频超材料消音器中的M个共振单元或K个声学穿孔板和L个共振单元，使M个共振单元或K个声学穿孔板和L个共振单元的声学阻抗谱型与宽频目标阻抗相同；
    具体的，
    3.1)当宽频超材料消音器为管道外的宽频超材料消音器，或者管道内的宽频分流式超材料消音器时；
    3.1.1)法布里-珀罗共振器作为共振单元：
    对于一个给定的宽频目标阻抗，为了实现作为圆频率ω函数的声学阻抗谱型Z(ω)，设计M个拥有同样横截面积的法布里-珀罗共振器；将这些共振器从长到短依次排列，记第m个共振器的长度为L m，其对应的第一阶共振频率为ω m＝πc/(2L m)；根据ω m的分布，得到单位频率内的模态数目M d；再通过调节每个共振器的长度L m，使得ω m的分布M d满足声学阻抗谱型Z(ω)；
    其间约束可用以下关系式(1)表示：
    Figure PCTCN2022137550-appb-100001
    其中
    Figure PCTCN2022137550-appb-100002
    φ是所有共振器开口面积和声波入射面总面积之比，ρ＝1.2千克/米 3表示空气密度，c＝343米/秒表示空气中声波的速度，ω是圆频率，单位赫兹，q是大于等于零的整数；
    3.1.2)亥姆霍兹共振器作为共振单元：
    记第m个共振器的开口面积为a m，开口长度为l，腔体横截面积为A m，腔体长度为L，那么该第m个亥姆霍兹共振器的共振频率为
    Figure PCTCN2022137550-appb-100003
    通过选取a m/A m使得ω m在频率上均匀分布；再在保持a m/A m数值不变的前提下，调整A m使得不同共振器的阻抗Z m叠加可以得到声学阻抗谱型Z(ω)：
    其间约束关系式(2)为：
    Figure PCTCN2022137550-appb-100004
    其中，Z(ω)的单位是千克·米 -2·秒 -1；
    Z m＝i(ω m 2-ω 2)/(ωf m)，Z m的单位是千克·米 -2·秒 -1；f m为共振强度，正比于 A m，单位为米 2/千克；ω m的单位是赫兹；ω是圆频率，单位是赫兹；
    Δf为目标频段，单位是赫兹；
    M为亥姆霍兹共振器的总数目；
    3.2)当超材料消音器为宽频简并吸音器时：
    3.2.1)对声学穿孔板的设计
    对于一个厚度为τ的硬质穿孔板，如果其上的圆孔孔径是d，孔隙率为φ，ρ是空气密度，v是空气的运动粘度，通过设计穿孔板的三个几何参数，使得16vρτ/(d 2φ)与声学阻抗谱型Z(ω)相等；
    其中，τ、d的单位为米，ρ＝1.2千克/米 3，v的单位米 2/秒；
    3.2.2)对宽频隔音器或宽频吸音器或宽频隔音器与宽频吸音器的组合设计
    根据步骤3.1)的方法得到声学阻抗谱型的频率范围不大于步骤3.2.1)中声学穿孔板声学阻抗谱型的频率范围的宽频隔音器或宽频吸音器或宽频隔音器与宽频吸音器的组合；
    3.2.3)将这两种声学结构结合在一起之后，得到所需的宽频简并吸收器；
    4)根据步骤3)设计的宽频超材料消音器以及其声学阻抗谱型，再次对管道内壁、宽频超材料消音器结构以及网状覆盖材料材质或/和结构进行优化，以实现对目标频率噪声的去除。
  11. 根据权利要求10所述的通风管道宽频超材料消音器的设计方法，其特征在于，步骤3)中选择宽频超材料消音器的类型的方法为：
    步骤一、
    当宽频噪声的反射能量对通风管道进风口端的环境和设备产生不利影响，或这些反射能量会再次反射进入管道中时，选择宽频吸音器或宽频超材料简并吸音器；否则，三者均适用；
    步骤二、
    当宽频超材料消音器沿着声波传播方向的整体尺寸＜目标频段内噪声声波波长上限，选择宽频隔音器或宽频超材料简并吸音器或宽频吸音器和宽频隔音器的组合；否则，三者均适用；
    步骤三、
    当宽频超材料消音器对气流影响敏感时，选择宽频隔音器或宽频吸音器或宽 频吸音器和宽频隔音器的组合；否则，三者均适用。
  12. 一种通风管道宽频超材料消音器的应用，其特征在于，用于可穿戴装置的降噪；
    将可穿戴装置的材料设置成向外凸出的硬质材料，硬质材料为2层或2层以上，相邻硬质材料层间设有数个密闭腔体，最内层硬质材料层或最内层硬质材料层的一部分与佩戴者皮肤之间形成密闭的内腔体；内腔体与其他密闭腔体之间通过各硬质材料层上的孔道连通，使内腔体与其他腔体共同形成通风管道，通风管道的进口设置于最内层硬质材料层或最外层硬质材料层上，出口设置于最内层硬质材料层或最外层硬质材料层上；宽频超材料消音器为宽频简并吸音器。
  13. 根据权利要求12所述的通风管道宽频超材料消音器的应用，其特征在于，将可穿戴装置的材料设置成向外凸出的硬质材料，硬质材料为2层，分别为最内层硬质材料层和外层硬质材料层，2层硬质材料层之间设有2个密闭腔体，分别为空腔一和空腔三，最内层硬质材料层内侧壁设有与佩戴者皮肤相接触的密封软垫，使最内层硬质材料层的一部分与佩戴者皮肤之间形成内腔体，内腔体为空腔二；在内腔体的最内层硬质材料层上设置孔道一和孔道二；空腔一通过孔道一与空腔二连通，空腔二通过孔道二与空腔三连通，使内腔体与空腔一和空腔三共同形成通风管道，通风管道的进口设置于空腔一的最内层硬质材料层上并且位于内腔体外部、出口设置于空腔三的最内层硬质材料层上并且位于内腔体外部；所述宽频超材料消音器为宽频简并吸音器，由声学穿孔板和设置在管道外的宽频吸音器组成，其中，声学穿孔板设置于孔道一和孔道二处，设置在管道外的宽频吸音器分别设置在空腔一和空腔三的侧壁。
  14. 根据权利要求12或13所述的通风管道宽频超材料消音器的应用，其特征在于，所述通风管道进口和/或出口处设置风扇。
  15. 根据权利要求12或13所述的通风管道宽频超材料消音器的应用，其特征在于，宽频简并吸音器所降噪音的频率为800至8000赫兹。
  16. 根据权利要求13所述的通风管道宽频超材料消音器的应用，其特征在于，设置在管道外的宽频吸音器的共振单元为亥姆霍兹共振器，亥姆霍兹共振器的腔体往复折叠成迷宫状；亥姆霍兹共振器为多个，一部分亥姆霍兹共振器开口于空腔一侧壁，另一部分亥姆霍兹共振器开口于空腔三侧壁。
  17. 一种通风管道宽频超材料消音器的应用，其特征在于，用于室内空气交换 设备的通风管道降噪；
    在位于室内空气交换设备的出风口处的通风管道侧壁安装设置在管道外的宽频吸音器，宽频吸音器的共振单元为法布里-珀罗共振器，共振单元的腔体在同一平面上往复折叠，由数个并列设置并且相互独立的共振单元组成一个套在通风管道外的降噪片层，降噪片层中每个共振单元均开口于通风管道侧壁，数个降噪片层堆叠排列组成宽频吸音器；
    所述宽频吸音器所降噪音的频率为200至8000赫兹。
  18. 一种通风管道宽频超材料消音器的应用，其特征在于，用于室外暖通设备的通风管道降噪；
    在位于室外暖通设备的通风管道内部安装设置在管道内的宽频吸音器；宽频吸音器的共振单元为法布里-珀罗共振器，共振单元的腔体在同一平面上往返折叠，并由数个并列设置并且相互独立的共振单元组成矩形、V字形、凹凸形、百叶形、阵列形或其他形状的宽频吸音器，每个共振单元均开口于通风管道内；
    所述宽频吸音器所降噪音的频率为200至8000赫兹。
  19. 一种通风管道宽频超材料消音器的应用，其特征在于，用于燃气热水器的入风管道降噪；
    在燃气热水器离心风机入口处的通风管道侧壁安装设置在管道外的宽频隔音器，宽频隔音器的共振单元为法布里-珀罗共振器，共振单元的腔体在同一平面上往复折叠，并由数个并列设置并且相互独立的共振单元组成一个套在管道外的宽频隔音器，每个共振单元均开口于通风管道侧壁；
    所述宽频隔音器所降噪音的频率为200至4000赫兹。
  20. 一种通风管道宽频超材料消音器的应用，其特征在于，用于设备动力部件的通风管道降噪；
    在设备动力部件的舱体的通风管道出口和/或入口位置的管道侧壁安装设置在管道外的宽频隔音器，宽频隔音器的共振单元为法布里-珀罗共振器，共振单元的腔体在一个平面上往复折叠，并由数个并列设置并且相互独立的共振单元组成一个套在管道外的宽频隔音器，每个共振单元均开口于通风管道侧壁；
    所述宽频隔音器所降噪音的频率为160至4000赫兹。
PCT/CN2022/137550 2022-12-01 2022-12-08 通风管道宽频超材料消音器及设计方法和应用 WO2024113402A1 (zh)

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