WO2018014190A1 - 含通孔的声学超材料挡片的消声器及其制备和装配方法 - Google Patents

含通孔的声学超材料挡片的消声器及其制备和装配方法 Download PDF

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Publication number
WO2018014190A1
WO2018014190A1 PCT/CN2016/090450 CN2016090450W WO2018014190A1 WO 2018014190 A1 WO2018014190 A1 WO 2018014190A1 CN 2016090450 W CN2016090450 W CN 2016090450W WO 2018014190 A1 WO2018014190 A1 WO 2018014190A1
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Prior art keywords
muffler
hole
film
baffle
acoustic
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PCT/CN2016/090450
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English (en)
French (fr)
Inventor
黄礼范
王术光
刘新刚
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黄礼范
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Priority to PCT/CN2016/090450 priority Critical patent/WO2018014190A1/zh
Publication of WO2018014190A1 publication Critical patent/WO2018014190A1/zh

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    • 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

Definitions

  • the invention relates to a muffler for a through-hole-containing acoustic metamaterial baffle which can customize an effective muffling frequency band, expand a low-frequency muffling bandwidth, and has a small fluid passage resistance and can enhance fluid heat transfer efficiency, and belongs to the field of acoustic devices.
  • Noise generated by pipes through gas or liquid medium such as industrial flow pipes, building fresh air system pipes, intake and exhaust pipes of fluid mechanical power equipment, refrigerant transfer pipes for refrigeration appliances such as air conditioner refrigerators, and various types of high pressure, high temperature and high speed
  • the exhaust gas is vented at the end, and the usual solution is to install a muffler device to effectively reduce the amount of noise passing through while ensuring a sufficient amount of fluid to pass smoothly.
  • the muffler is mainly divided into three categories according to the working principle and structural form: a resistance muffler, a resistive muffler and an impedance composite muffler.
  • the resistant muffler mainly uses partial vibration of the acoustic characteristics of the pipeline, such as expansion, contraction or bypass branch, to achieve partial sound wave bounce.
  • the resistive muffler usually adopts a sound absorbing material lined with the inner wall of the pipe, such as foam and fiber cotton. The porous material will continuously absorb the noise in the pipeline during the propagation process; the impedance composite muffler has the structural characteristics of the resistance and impedance muffler.
  • the most widely studied structure is the axial installation in the expansion chamber.
  • the perforated or microperforated tube is filled with a sound absorbing material in the gap between the perforated tube and the muffler wall.
  • the muffler can simultaneously use the abrupt structure to bounce the acoustic wave, absorb the noise of the specific frequency band by using the cavity resonance characteristic of the perforated tube and the muffler wall, and absorb the transmitted high-frequency sound wave by using the filled sound absorbing material.
  • the effective muffling frequency band of the resistant muffler has an inverse relationship with its structural size, for the low frequency noise with large wavelength scale and long propagation distance, the corresponding resistant muffler structure size needs to be sufficiently large.
  • a simple expansion-cavity-resistant muffler designed to propagate 100 Hz noise in an air medium should have an expansion cavity length of at least a quarter of the wavelength of the desired suppression noise, i.e., about 85 cm, in order to provide effective muffling.
  • the muffling amount is close to zero, and the prior art is inside the expansion cavity.
  • the resistive muffler uses a sound absorbing material, on the one hand, its effective muffling frequency band is limited to high frequency, on the other hand
  • the sound absorbing material is in direct contact with the fluid, and it is inevitable to absorb moisture, smash or fall off during the working process, which affects the service life.
  • the impedance composite muffler has both resistance and resistance characteristics, it can not avoid the problem that the sound absorbing material is exposed to the pipeline fluid, which limits its application to high temperature, humidity, high flow rate, high cleaning requirements, and internal structure.
  • Complex, high cost of manufacturing, maintenance and repair Choinese Open Patent: CN204921097U, CN104564285A, US Published Patent: US6332511B1, US8146574B2).
  • the Chinese patent application CN105090670A combined the concept of acoustic metamaterial with a specific muffling device, and disclosed a thin film acoustic super material muffler. It installs a number of thin film acoustic metamaterial units on the side of the muffler tube wall, and uses the vibration mode generated by the acoustic super material unit cell under the excitation of the pipeline noise to reduce the noise level of the specific frequency.
  • the invention defines that the surface of the acoustic metamaterial unit cell is parallel to the incident direction of the noise in the duct, although the resistance to the passing fluid is somewhat reduced, the effective muffling bandwidth is extremely narrow, as described in the embodiment of the invention.
  • the muffler has a working bandwidth of only a few ten hertz and is difficult to handle low frequency broadband noise conditions.
  • the technical problem solved by the present invention is to provide a technical solution capable of overcoming the problem of narrow low-frequency muffling bandwidth existing in the existing thin film acoustic super material muffler, and to provide an acoustic super-via with a through hole vertically or obliquely installed along a pipe flow direction.
  • the Baffled Acoustic Metamaterial Silencer (“BAMS”) has a lower frequency noise reduction effect than the equivalent aperture perforated blank and the equivalent total perforated area microperforated blank silencer.
  • the through-hole size on the Perforated Acoustic Metamaterial Baffle (“PAMB”) can be designed according to the requirements of the flow and the muffling frequency band to ensure sufficient heat flow, air flow or liquid flow. At the same time of smooth passage, the noise level is effectively reduced.
  • the invention also provides an improved technical solution of the resistant muffler, which comprises the working frequency band of the PAMB installed on the internal section of the conventional resistant muffler, covering the standing wave trough frequency band of the original muffler, and significantly improving the sound transmission performance of the frequency band. Broaden the muffling bandwidth. Because it does not rely on the structure of the muffler The muffling principle that matches the attenuation wavelength is based on the local resonance mechanism of PAMB, and further excellent acoustic low-frequency noise cancellation can be obtained under the premise that the structure of the muffler is sufficiently compact.
  • the invention also provides an improved resistive muffler technical solution, which uses a thicker layer (more than 5 mm thick) or a plurality of layers of PAMB to seal the sound absorbing material, and transmits sound energy through a film matched with the impedance of the sound absorbing material, thereby further
  • the conversion to thermal energy consumption effectively solves the problem of the direct contact of the sound absorbing material of the conventional resistive muffler with the fluid.
  • the invention also provides a muffler technical solution for enhancing the heat transfer efficiency of a fluid, which on the one hand improves the temperature difference and heat conduction rate of the medium on both sides of the through hole by the vibration generated by the PAMB under the excitation of the sound wave; on the other hand, when the fluid passes
  • the flow-induced vibration generated by the PAMB film can increase the fluid turbulence at the heat source adhering, hinder the formation of the thermal boundary layer and the velocity boundary layer, and accelerate the heat exchange efficiency.
  • the invention also provides a frequency modulation and preparation method of the PAMB and an assembly method of the muffler.
  • the PAMB working frequency band is adjusted by changing the structural dimensions and material composition of the PAMB frame, the constraining body and the film; the PAMB is prepared by integral molding or pre-assembly assembly method, and the roll assembly, the interference fit, the gap welding, the combination splicing, etc. are utilized.
  • the process method performs the assembly of the muffler.
  • a muffler comprising an inlet tube, an outlet tube, a hollow expansion chamber between the inlet tube and the outlet tube, and a PAMB disposed vertically or obliquely on at least one section of the hollow expansion chamber.
  • the PAMB is mounted on a cross section along the direction of flow of the conduit.
  • the PAMB includes a frame, and at least one binding body is disposed in the frame. At least one surface of the two sides of the frame is covered with a film, and the binding body and the film are provided with at least one through hole.
  • the cross-sectional shape of the hollow expansion chamber is determined according to parameters such as the installation space of the muffler and the expansion ratio of the muffler; preferably, the cross-sectional shape of the hollow expansion chamber is circular, elliptical, rectangular, or regular polygonal, and the longitudinal cross-sectional shape of the hollow expansion chamber is Rectangular, tapered, wavy.
  • the frame is a hollow structure, and the outer contour shape is consistent with the cross-sectional shape of the hollow expansion cavity; the binding body is disposed inside the frame, and the binding body and the frame are rigidly connected by at least one connecting rod; the outer peripheral area of the film fits the surface of the frame, and the inside The region is constrained by the constraining body; preferably, the constraining body and the connecting rod are flush with the frame, and the connecting rod is a part of the binding body for restraining the vibration of the film.
  • the through-hole area of the binding body is determined according to the following manner: when the flow efficiency is high, the large-constrained through-hole area is selected; in the case where the anti-sounding frequency band tends to be low-frequency, the frame and the film are ensured. Under the premise that the geometrical dimensions and material parameters are unchanged, a small-sized through-hole aperture is selected.
  • the shape, position and size of the holes in the binding body and the film are the same or different; preferably, the shape, position and size of the through holes are the same; preferably, the shape of the through holes is any geometric shape; more preferably, the geometric shape is
  • the symmetrical regular shape is further preferably a circular shape, an elliptical shape, or a regular polygonal shape.
  • the contact area of the binding body with the film is a line or a face; preferably, the contact shape is a symmetrically regular geometry; more preferably, the geometric shape is a circle, an ellipse, or a regular polygon.
  • the number of the constraining bodies is mainly determined according to the muffling frequency band. The more the number of the constraining bodies, the smaller the vibrating area of the film, and the more the muffling frequency band of the muffler tends to be high frequency.
  • An improved resistant muffler characterized in that at least one PAMB is disposed on an internal section of a conventional resistant muffler, and a working frequency band of a preferred PAMB covers a standing wave muffling trough frequency band of the conventional resistant muffler; more preferably The peak operating frequency of the PAMB is consistent with the frequency of each order standing wave.
  • An improved resistive muffler characterized in that the sound absorbing material is closed with one or more layers of PAMB to prevent direct contact of the sound absorbing material with the fluid; preferably the thickness of the layer of PAMB is greater than 5 mm; preferably said The surface of both sides of the frame of a layer of PAMB is covered with a film, and the two layers of film are filled with a porous material matching the film impedance; preferably, the thickness and/or material of the two films are different. When the thickness and/or material are different, the two films exhibit different characteristic vibration frequencies, which is beneficial to expand the working bandwidth.
  • the multi-layered PAMB is positioned by a stent, and a layer of an impermeable film is coated on the periphery of the stent, and a hole matching the impedance of the film is filled in a cavity between the impervious film and the wall surface of the expansion chamber or between the two films.
  • the material preferably the material that is impermeable to the film is the same as the film of PAMB; preferably the porous material is glass fiber cotton or open and closed cell foam.
  • a muffler for enhancing the heat transfer efficiency of a fluid characterized in that, on the one hand, the vibration generated by the PAMB under the excitation of the sound wave improves the temperature difference and the heat conduction rate of the medium on both sides of the through hole; on the other hand, when the fluid passes, the PAMB
  • the flow-induced vibration generated by the film can increase the fluid turbulence at the adhesion of the heat source, hinder the formation of the thermal boundary layer and the velocity boundary layer, and accelerate the heat exchange efficiency; it is used to enhance the heat transfer efficiency of the fluid.
  • An array blank comprising the PAMB, which is formed by combining a plurality of PAMBs in an in-plane direction array; when wide-band noise reduction is required, it is preferred that the geometric dimensions and material parameters of the respective PAMBs forming the array blank are different when When narrowband muffling is desired, it is preferred that the individual PAMBs forming the array flap have the same geometry and material parameters.
  • the material of the frame and the binding body of the PAMB is a metal material or a non-metal material, preferably the metal material is aluminum, iron, steel, copper, and preferably the non-metal material is wood, ceramic, rubber, glass, gypsum, cement, polymer polymerization. Or a composite fiber material; the material of the film is a high molecular polymer film material, a metal film material or an elastic film material, and the polymer film material is preferably a polyetherimide film, a poly
  • the vinyl chloride film, the polyethylene film, and the metal thin film material are preferably aluminum and aluminum alloy films, titanium and titanium alloy films, and the elastic film material is preferably a rubber film, a silicone film, or a latex film.
  • a method for eliminating a standing wave muffling trough of a conventional resistant muffler comprising the steps of: installing a through hole-containing acoustic metamaterial baffle on an inner cross section of a conventional resistant muffler, and including a through hole
  • the operating frequency band of the acoustic metamaterial baffle covers the standing wave muffling trough frequency band of the conventional resistance muffler; preferably, the working frequency band of the through hole-containing acoustic metamaterial baffle is consistent with the low frequency first order standing wave frequency.
  • a method for adjusting the muffling frequency band of the muffler under the premise that the shape and size of the muffler expansion cavity are unchanged, the effective work of adjusting the PAMB is realized by changing the structural dimensions and material parameters of the frame, the binding body and the film of the PAMB.
  • the frequency band improves the muffler performance of the muffler in this band.
  • a method for assembling the PAMB wherein the perforated binding body and the frame are prepared by an integral molding technique, or a perforated binding body preform and a frame preform are manufactured, and the perforated binding body preform is connected through the connection.
  • the rod is rigidly connected to the frame preform to form a frame, and then the film is covered on the frame in a freely stretched state, and is fixedly connected, and finally punched on the film; further, in order to ensure the stability of the PAMB, two
  • the frame described in the layer holds the film in the middle and is fixedly connected; preferably processed into a one-piece frame by milling, casting, stamping, laser cutting or 3D printing, or by milling, casting, stamping, laser cutting or 3D
  • the printing technique produces a perforated binding preform and a bezel preform; preferably the fixed joint is glued, heat welded or mechanically riveted.
  • a method for assembling the muffler characterized in that the method first sends the PAMB to a predetermined position inside the hollow tube by a positioning tool, and then moves the roller cutter head to a corresponding position on the outer wall surface of the hollow tube and applies a certain pressure.
  • the PAMB is embedded in the hollow tube; the hollow tube is formed at both ends.
  • a method for assembling the muffler characterized in that the method inserts a PAMB into a hollow tube by means of stamping or thermal assembly, and fixes the acoustic hypermaterial block containing the through hole in the middle by using the interference of the interference fit The predetermined position of the empty pipe; the hollow pipe is formed at both ends.
  • a method for assembling the muffler wherein the method installs the PAMB into a predetermined position in the hollow tube through a positioning fixture, and then fixes the PAMB by spot welding using ultrasonic, laser, argon arc welding, or the like, or adopts a sleeve, A structure such as a spring is positioned to position the PAMB; the hollow tube is formed at both ends.
  • the forming of the mouth is preferably by die forming, spin forming, and inlet and outlet pipe welding.
  • a method for assembling the muffler characterized in that two or more muffler splicing members are manufactured by casting, turning and stamping processes, preferably the muffler splicing piece is a shaft-cutting half-type, in which half of the muffler splicing pieces are in a predetermined position After the fixed PAMB is installed, the other half of the muffler splicing piece is fastened and spliced; preferably, the method of fixing and fixing the PAMB includes welding, groove clamping, sleeve positioning, and preferably the jointing method is Welding, riveting, articulating, gluing.
  • the inside of the muffler is installed vertically or obliquely along the pipe flow direction.
  • the low frequency muffling bandwidth and the muffling amount are better than the same aperture perforated baffle muffler, the equivalent sum perforated area micro perforated baffle muffler and the existing stickers.
  • a film acoustic super material muffler installed in parallel with the wall surface.
  • the PAMB is different from the conventional thin film local resonance type acoustic super material, which does not need to install the weight mass, and does not accidentally fall off during the working process of the weight mass, so that the working stability of the muffler is strengthened.
  • the size of the through hole of the PAMB can be designed according to the requirements of the flow demand and the muffling frequency band, and the noise level can be effectively reduced while ensuring a sufficient amount of heat flow, air flow or liquid flow.
  • the working frequency band of the PAMB inserted into the cross section of the conventional resistant muffler, it is consistent with the standing wave muffling low valley of the original muffler, which significantly improves the muffling performance at the standing wave frequency and broadens the muffling bandwidth.
  • the problem of the standing wave noise reduction of the conventional resistance muffler is completely solved without changing the overall structure size of the expansion chamber.
  • the inside of the muffler uses a thicker or multi-layered PAMB to seal the sound absorbing material, and the sound energy is transmitted through the film to enter the sound absorbing material, thereby converting into heat energy consumption. It effectively solves the problem that the sound absorbing material in the traditional resistive muffler is in direct contact with the fluid, avoids the occurrence of moisture absorption, smashing and falling off of the sound absorbing material, and significantly prolongs the service life.
  • the inside of the muffler utilizes the vibration of the PAMB's own structure under the excitation of sound waves to accelerate the hot and cold air exchange process at the attachment wall, ensuring that the temperature difference of the medium on both sides of the hole is maintained at a higher level, and a larger heat is ensured for a long time.
  • Conduction rate when a fluid passes, the membrane vibration of PAMB can increase the fluid turbulence at the heat source adhering, hinder the formation of the thermal boundary layer and the velocity boundary layer, and accelerate the convective heat transfer efficiency.
  • the PAMB structure is simple, and the batch processing technology is mature.
  • the muffler has a simple internal structure, is difficult to process and assemble, and has a compact structure, and is suitable for various installation spaces.
  • FIG. 1 is a schematic view showing the general configuration of an acoustic metamaterial baffle muffler of the present invention and a type of PAMB structure included therein.
  • FIG. 2 is a schematic structural view of a basic type acoustic super material block muffler according to Embodiment 1 of the present invention.
  • FIG. 3 is a cross-sectional view showing the structure of a basic acoustic metamaterial baffle muffler, a similar aperture perforated baffle muffler, and an equivalent sum perforated area microperforated baffle muffler according to Embodiment 1 of the present invention.
  • Embodiment 4 is a basic acoustic super material block muffler according to Embodiment 1 of the present invention, and the same aperture is worn. Comparison of the results of finite element simulation calculation of the sound transmission loss of the hole block muffler, the equivalent sum perforation area micro-perforated block muffler and the non-stop muffler.
  • Figure 5 is a schematic diagram of an acoustic impedance tube test system for measuring the acoustic loss of a muffler sample using a four-microphone single load method.
  • Embodiment 6 is a measurement result of a sound loss test of a basic type acoustic super material block muffler, a same aperture perforated block muffler, an equivalent total perforated area microperforated block muffler and a non-stop muffler according to Embodiment 1 of the present invention. A comparison of the results of the meta-simulation calculations.
  • FIG. 7 is a velocity direction distribution of a basic acoustic supermaterial baffle muffler, a similar aperture perforated baffle muffler, an equivalent total perforated area microperforated baffle muffler, and a non-stop muffler according to Embodiment 1 of the present invention; Figure.
  • FIG. 8 is a comparison of pressure loss of different inlet air flow rates of a basic acoustic super material baffle muffler, a similar aperture perforated baffle muffler, an equivalent total perforated area microperforated baffle muffler and a non-stop muffler according to Embodiment 1 of the present invention; Figure.
  • FIG. 9 is a comparison diagram of heat transfer efficiency of a basic type acoustic super material block muffler and a same aperture perforated block muffler according to Embodiment 1 of the present invention.
  • FIG. 10 is a schematic structural view of a muffler including two sets of PAMBs according to Embodiment 2 of the present invention.
  • Figure 11 is a cross-sectional view showing the structure of a muffler comprising two sets of PAMBs and a muffler comprising two sets of perforated baffles of the same aperture according to Embodiment 2 of the present invention.
  • FIG. 12 is a comparison diagram of finite element simulation calculation results of sound transmission loss of a muffler comprising two sets of PAMBs and a muffler comprising two sets of equal aperture perforated baffles according to Embodiment 2 of the present invention.
  • FIG. 13 is a schematic structural view of a closed-impedance composite muffler of a sound absorbing material composed of two layers of PAMB intermediate-filled sound absorbing materials according to Embodiment 3 of the present invention.
  • FIG. 15 is a schematic structural view of a three-dimensional stereo type super-material block muffler according to Embodiment 4 of the present invention.
  • FIG. 16 is a comparison diagram of finite element simulation calculation results of a three-dimensional stereo type super-material block muffler and a non-block muffler according to Embodiment 4 of the present invention.
  • Figure 17 is a schematic view showing the structure of a sandwich type PAMB according to Embodiment 5 of the present invention.
  • FIG. 18 is a schematic structural view of a tilt type acoustic metamaterial block muffler according to Embodiment 6 of the present invention.
  • FIG. 19 is a comparison diagram of sound transmission loss test results of a tilt type acoustic metamaterial block muffler including different tilt angles PAMB according to Embodiment 6 of the present invention.
  • FIG. 20 is a schematic structural diagram of a PAMB array block muffler composed of a plurality of PAMB in-plane arrays according to Embodiment 7 of the present invention.
  • Figure 21 is a schematic view showing the assembly structure of the flange assembly, the screw assembly and the welding assembly acoustic super material block muffler according to the embodiment 8 of the present invention.
  • the inlet tube described in Example 2 the expansion chamber described in Example 28, the outlet tube described in 29-Example 2, and the first group PAMB, 31-Example
  • FIG. 1 is a generalized configuration of an acoustic metamaterial baffle muffler of the present invention comprising an outer cavity of the muffler and a plurality of vertically or obliquely placed acoustic metamaterial baffles (PAMB) therein.
  • the outer cavity of the muffler comprises an inlet pipe (1), an outlet pipe (3) and a hollow expansion cavity (2)
  • the PAMB is vertically or obliquely placed on a plurality of sections in the hollow expansion cavity.
  • a PAMB (4) as an example, it comprises a frame (8), and a constraining body (9) rigidly connected to the frame is disposed in the frame, and a film (6) is covered on one side of the frame and is covered by the film.
  • the inner restraint body (9) is constrained, and the through holes (10), (7) are respectively disposed on the constraining body (9) and the film (6).
  • Embodiment 2 is a basic acoustic super material baffle muffler according to Embodiment 1 of the present invention, which has only one set of vertically placed basic type PAMB (14), and the muffler external cavity includes an inlet pipe (11) and an expansion cavity. (12) and the outlet pipe (13).
  • FIG. 3 is a cross-sectional view showing the structure of a basic acoustic metamaterial baffle muffler, a similar aperture perforated baffle muffler, and an equivalent sum perforated area microperforated baffle muffler according to Embodiment 1 of the present invention.
  • the outer cavity material of the muffler is 6063 grade aluminum alloy.
  • the basic PAMB (14) has a circular frame with an outer diameter of 46 mm, an inner diameter of 40 mm and a thickness of 2 mm.
  • the outer diameter of the perforated body is 16 mm, and the diameter of the constraining hole is 10 mm.
  • the thickness of the through hole is also 10 mm;
  • the double-arm connecting rod between the hole-constrained body and the frame has a rectangular cross section, a width of 3 mm and a thickness of 2 mm.
  • the frame, the perforated binding body and the double-arm connecting rod are made of the same material, all of which are SPCC cold-rolled steel; the perforated film is made of polyetherimide.
  • the perforated flap (15) has a circular outer shape with an outer diameter of 46 mm, an inner diameter of 10 mm and a thickness of 0.75 mm; and the material is SPCC cold rolled steel.
  • the microperforated baffle (16) has an outer diameter of 46 mm and a thickness of 0.75 mm.
  • the inner central region is distributed with 25 micropores having a diameter of 2 mm, and the center distance of the micropores is 7 mm; the material is SPCC cold rolled steel.
  • the surface densities of the three kinds of flaps were 5.67 kg/m 3 , and the perforation rate (the area of the through holes/the total area of the flaps) was 4.73%.
  • the dotted line corresponds to the result of the no-block muffler
  • the dotted line corresponds to the result of the perforated block muffler
  • the dotted line corresponds to the result of the micro-perforated block muffler
  • the solid line corresponds to the result of the basic acoustic super material block muffler.
  • the transmission loss spectrum shows a distinct trough near 700 Hz and 1400 Hz, and the noise reduction is almost zero, because the longitudinal dimension L of the expansion chamber is exactly equal to an integral multiple of the half wavelength of the incident acoustic wave.
  • a perforated baffle is placed inside the expansion chamber such that the two acoustic loss troughs move to near 460 Hz and 1250 Hz, respectively.
  • the corresponding frequency of the low sound transmission loss is located near 600 Hz and 1300 Hz.
  • the basic type acoustic super material block muffler according to Embodiment 1 of the present invention is directed to the low frequency first-order sound transmission loss valley, and utilizes the total reflection vibration mode generated by the PAMB sound wave excitation at the corresponding frequency of the low valley to efficiently reflect the sound wave and significantly improve the sound wave.
  • the amount of transmitted sound loss near this frequency As shown in Fig. 4, the acoustic loss of the basic acoustic metamaterial baffle muffler is higher than 10 dB in the continuous low and medium frequency bands of 50 to 1300 Hz, especially at 460 Hz, which is about 30 dB higher than the perforated block muffler.
  • FIG. 5 is a schematic diagram of an acoustic impedance tube test system for measuring the acoustic loss of a muffler sample using a four-microphone single load method.
  • the acoustic impedance tube is mainly composed of an incident acoustic tube (18) and a transmissive acoustic tube (19), and a sound source (17) is disposed at the end of the incident acoustic tube (18), which generates a broadband white noise excitation sound wave at the entrance transition tube.
  • the microphone (21) on (21) has been developed into a plane acoustic wave whose wavefront amplitude tends to be consistent.
  • the sound wave passes through the muffler to be tested (23) and enters the exit transition tube (22), and finally enters the transmission sound tube (19).
  • a sufficiently long sound absorbing tip (20) is placed at the rear end of the transmission acoustic tube (19) to minimize the influence of multiple reflections of sound waves on the test results.
  • the test system has an effective test frequency range of 50 Hz to 1600 Hz and a cutoff frequency of 1720 Hz.
  • FIG. 6 is a measurement result of a sound loss test of a basic type acoustic super material block muffler, a same aperture perforated block muffler, an equivalent total perforated area microperforated block muffler and a non-stop muffler according to Embodiment 1 of the present invention.
  • Figure 6(a) corresponds to the result of the no-block muffler, where the solid line is the simulation result and the open circle is the test result
  • Figure 6(b) corresponds to the result of the perforated block muffler, where the solid line is the simulation result and the open circle is the test.
  • Figure 6(c) corresponds to the results of the microperforated baffle muffler, where the solid line is the simulation result and the open circle is the test result
  • Figure 6(d) corresponds to the basic acoustic super material block muffler result, where the solid line is the simulation result.
  • the open circle is the test result.
  • the simulation results agree well with the experimental results, which indicates that the simulation model is correct and can be used to analyze the microscopic mechanism of the sound loss characteristics of the muffler. It also shows that the simulation model is suitable for the muffling frequency band of the acoustic super material block muffler. design.
  • Embodiment 7 is a basic acoustic super material baffle muffler, a similar aperture perforated baffle muffler, an equivalent sum perforated area microperforated baffle muffler and a non-stop muffler according to Embodiment 1 of the present invention, under the condition of 460 Hz frequency sonic excitation, the muffler The velocity direction distribution of the air bubbles in the internal chamber.
  • Figure 7 (a) corresponds to the result of the no-block muffler
  • Figure 7 (b) corresponds to the result of the perforated block muffler
  • Figure 7 (c) corresponds to the result of the micro-perforated block muffler
  • Figure 7 (d) corresponds to the basic acoustic super material Block muffler results.
  • the black arrow indicates the direction of incidence of the sound wave. It can be clearly seen that the basic acoustic super-material baffle muffler has obvious acoustic vortex in the front and rear regions of the baffle, which is obviously different from other types of muffler.
  • the non-block muffler only the sound wave reflection phenomenon occurs in the near wall surface area at the outlet end, and the area where the sound reflection is reflected by the perforated block muffler is advanced, and the micro perforated block muffler appears compared to the perforated block muffler.
  • the area of sound reflection is closer to the exit end.
  • the acoustic reflection area of the acoustic metamaterial baffle muffler appears at the upstream end of the acoustic metamaterial baffle, and the entire muffler chamber is dominated by back-propagating sound waves.
  • the circle mark corresponds to the result of the no-block muffler
  • the square mark corresponds to the result of the perforated block muffler
  • the triangle mark corresponds to the result of the micro-perforated block muffler
  • the star mark corresponds to the result of the basic type acoustic super material block muffler.
  • the pressure loss of the micro-perforated baffle muffler is the largest among the four under different input flow rate input conditions, and the basic acoustic super material baffle muffler is the second, while the non-stop muffler has the lowest pressure loss.
  • the inlet flow rate of the airflow piping system is less than 10 m/s.
  • the pressure loss of the four muffler is small, and both are below 200 Pa.
  • FIG. 9 is a comparison diagram of heat transfer efficiency of a basic type acoustic super material block muffler and a same aperture perforated block muffler according to Embodiment 1 of the present invention.
  • the dotted line corresponds to the result of the perforated block muffler
  • the solid line Corresponding to the basic acoustic super material block muffler results. It can be clearly seen that the heat transfer efficiency of the basic acoustic metamaterial baffle muffler is higher than that of the equivalent aperture perforated baffle muffler, and the outlet temperature reaches the steady state value in a shorter time.
  • the diameter of the through hole of the basic type acoustic super material blocking muffler and the inner aperture of the same aperture perforated blank muffler according to Embodiment 1 of the present invention is the same as the diameter of the inlet pipe and the outlet pipe, both being 10 mm.
  • the through-flow heat dissipation effect of the conventional perforated baffle muffler is already ideal enough, so the PAMB acoustic super material baffle muffler does not have a significant difference in heat transfer efficiency.
  • FIG. 10 is a schematic structural view of a muffler including two sets of PAMBs according to Embodiment 2 of the present invention.
  • the outer chamber of the muffler comprises an inlet tube (27), an expansion chamber (28) and an outlet tube (29).
  • the expansion chamber (28) is vertically installed with two sets of PAMBs (30) and (31) spaced apart by a certain distance, and the structural size thereof. And the material composition is not exactly the same, respectively for different anechoic trough bands.
  • Figure 11 is a cross-sectional view showing the structure of a muffler comprising two sets of PAMBs and a muffler comprising two sets of equal aperture perforated baffles according to the second embodiment of the present invention.
  • the black arrow indicates the incident direction of the sound wave.
  • the outer cavity material of the muffler is 6063 grade aluminum alloy.
  • the structural dimensions and material composition of the two internal PAMBs are not identical.
  • the first group of PAMB (30) has a circular frame with an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; the outer diameter of the hole-constrained body is 18 mm, and the diameter of the constraining body hole is 12 mm; The thickness is 0.05 mm, and the diameter of the through hole is also 12 mm; the double-arm connecting rod between the hole-binding body and the frame has a rectangular cross section, a width of 3 mm, and a thickness of 2 mm.
  • the frame of the second group PAMB (31) is also circular, with an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; an outer diameter of the hole-constrained body is 16 mm, and a diameter of the constraining body hole is 10 mm; the thickness of the perforated film The diameter of the through hole is also 10 mm; the double-arm connecting rod between the hole-constrained body and the frame has a rectangular cross section, a width of 3 mm and a thickness of 2 mm.
  • the frame of the two groups of PAMB, the hole-constrained body and the material of the double-arm connecting rod are the same, all of which are SPCC cold-rolled steel; the material of the perforated film is polyetherimide.
  • the through hole sizes of the two sets of perforated baffles (32) and (33) are respectively corresponding to the two groups of PAMB (30) and (31) correspond.
  • the perforated baffle (32) has a circular outer shape, an outer diameter of 46 mm, an inner diameter of 12 mm, and a thickness of 0.75 mm; the perforated baffle (33) is also annular, having an outer diameter of 46 mm, an inner diameter of 10 mm, and a thickness of 0.75mm; the materials of the two sets of perforated baffles are all SPCC cold rolled steel.
  • the surface density of the first group of sheets (30) and (32) was 5.49 kg/m 3 , and the perforation rate was 6.81%; the surface density of the second group of sheets (31) and (33) was 5.67 kg/ m 3 , the perforation rate was 4.73%.
  • FIG. 12 is a comparison diagram of simulation results of sound transmission loss of a muffler comprising two sets of PAMBs and a muffler comprising two sets of equal aperture perforated baffles according to Embodiment 2 of the present invention.
  • the solid line corresponds to the muffler results with two sets of PAMB
  • the dashed line corresponds to the results of two sets of perforated block muffler.
  • FIG. 13 is a schematic structural view of a sound absorbing material closed-resistance composite muffler composed of two layers of PAMB intermediate-filled sound absorbing materials according to Embodiment 3 of the present invention.
  • the sound absorbing material sealing impedance composite type flap (35) is composed of two layers of PAMB sandwiching the sound absorbing material.
  • the first layer of PAMB (including the frame (37) and the perforated film (36)) and the second layer of PAMB (including the frame (41) and the perforated film (42)) are connected by a bracket (40), and the bracket (40) is laid around the periphery.
  • the annular coating film (39) is filled with a sound absorbing material (38) between the annular coating film (39) and the inner wall surface of the muffler cavity (34).
  • the structural size and material composition of the muffler outer cavity (34) are the same as those in the first embodiment.
  • the first layer PAMB has a circular ring shape, an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; an outer diameter of the hole-constrained body is 16 mm, a diameter of the constraining body hole is 10 mm; and a thickness of the perforated film is 0.05 mm.
  • the diameter of the through hole is also 10 mm; the double-arm connecting rod between the hole-binding body and the frame has a rectangular cross section, a width of 3 mm and a thickness of 2 mm.
  • the frame of the second layer PAMB is also circular, with an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; an outer diameter of the hole-constrained body is 11 mm, a diameter of the constraining body hole is 5 mm; and a thickness of the perforated film is 0.05 mm.
  • the diameter of the through hole is also 5 mm;
  • the double-arm connecting rod between the hole-binding body and the frame has a rectangular cross section, a width of 3 mm and a thickness of 2 mm.
  • the two-layer PAMB has the same material as the frame, the hole-constrained body and the double-arm connecting rod, all of which are SPCC cold-rolled steel; the perforated film is made of polyetherimide.
  • the bracket (40) is composed of two support rods, which are 50 mm long, 3 mm wide and 2 mm thick.
  • the annular coating film (39) has a thickness of 0.038 mm and the material is a polyetherimide.
  • the sound absorbing material (38) is glass fiber cotton with a bulk density of 9.6 kg/m 3 , a flow resistance of 19,000 Nsm -4 and a filling length of 50 mm.
  • Figure 14 is a drawing of a two-layer PAMB intermediate filled sound absorbing material according to Embodiment 3 of the present invention.
  • the solid line corresponds to the result of the closed-impedance composite muffler of the sound absorbing material
  • the broken line corresponds to the muffler result of the two layers of PAMB without filling the sound absorbing material.
  • the sound-absorbing material closed-resistance composite muffler Compared with the muffler with no sound-absorbing material in the middle of the two layers of PAMB, the sound-absorbing material closed-resistance composite muffler has no obvious muffling collapse in the whole frequency band, and the overall noise-reducing effect is excellent.
  • FIG. 15 is a schematic structural view of a three-dimensional stereo type super-material block muffler according to Embodiment 4 of the present invention.
  • the frame (45) and the hole-constrained body (46) are not in the same plane, and the two are at a certain distance and are rigidly connected by the inclined connecting rod (47), and the film (48) is wrapped in a circular shape on the frame (45) and The side of the restraint body (46).
  • the structural size and material configuration of the muffler outer cavity (43) are the same as those in the first embodiment.
  • the frame (45) of the three-dimensional stereotype PAMB has a circular shape, an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; an outer diameter of the hole-constraining body (46) is 16 mm, and a diameter of the constraining body hole is 10 mm; a perforated film (48) has a thickness of 0.05 mm, and the diameter of the upper through hole is also 10 mm; the double-armed inclined connecting rod between the hole-constrained body and the frame has a rectangular cross section, a width of 3 mm, a thickness of 2 mm, and an axial vertical height of 20 mm.
  • the frame (45), the perforated binding body (46) and the inclined connecting rod (47) are of the same material and are all SPCC cold-rolled steel; the film (48) is made of polyetherimide.
  • FIG. 16 is a comparison diagram of simulation results of sound transmission loss of a three-dimensional stereo type super-material block muffler and a non-block muffler according to Embodiment 4 of the present invention.
  • the solid line corresponds to the result of the three-dimensional stereoscopic super material block muffler
  • the dotted line corresponds to the result of the no-block muffler.
  • the effective muffling frequency of the three-dimensional stereo type super material baffle muffler appears near 400 Hz, and the sound transmission loss is improved by about 3 to 5 dB compared with the non-stop muffler.
  • This embodiment is especially suitable for a sound-damping pipeline with a small diameter.
  • the three-dimensional stereotype PAMB can significantly improve the vibration area of the membrane and ensure a good low-frequency noise reduction effect.
  • Figure 17 is a schematic view showing the structure of a sandwich type PAMB according to Embodiment 5 of the present invention. It is constructed by attaching two layers of frames (50) and (51) to the left and right sides of the perforated film (52) and clamping the perforated film (52).
  • the configuration described in this embodiment can improve the working stability of the PAMB, making it suitable for high flow rates, strong impact currents and the like.
  • FIG. 18 is a schematic structural view of a tilt type acoustic metamaterial block muffler according to Embodiment 6 of the present invention.
  • the inclined PAMB (54) is obliquely placed at an inner angle of the outer cavity (53) of the muffler at an angle ⁇ .
  • the structural size and material composition of the muffler outer cavity (53) are the same as those in the first embodiment.
  • the tilt type PAMB (54) has an installation tilt angle of ⁇ and an axial cross-sectional projection size similar to that of the basic type PAMB (14) shown in Embodiment 1.
  • the frame of the inclined PAMB (54), the perforated binding body and the material of the connecting rod are the same. All are SPCC cold-rolled steel; the thickness of the film is 0.05mm, and the material is polyetherimide.
  • FIG. 19 is a comparison diagram of sound transmission loss test results of a tilt type acoustic metamaterial block muffler including different tilt angles PAMB according to Embodiment 6 of the present invention.
  • the smaller the installation inclination angle ⁇ the more the noise reduction peak of the PAMB acts toward the low frequency, that is, when the installation inclination angle ⁇ is reduced from 45° to 30°, the noise reduction peak moves from 600 Hz to 450 Hz, and the sound transmission loss in other frequency bands
  • the change is not big.
  • the configuration of this embodiment is very suitable for the case where the pipe diameter is small and the flow demand is high.
  • FIG. 20 is a schematic structural diagram of a PAMB array block muffler composed of a plurality of PAMB in-plane arrays according to Embodiment 7 of the present invention.
  • the configuration described in this embodiment can ensure that the PAMB array flap has sufficient bending rigidity to facilitate the installation of the flap inside the hollow expansion chamber of the large-size section.
  • Figure 21 is a schematic view showing the assembly structure of the flange assembly, the screw assembly and the welding assembly acoustic super material block muffler according to the embodiment 8 of the present invention.
  • 21(a) corresponds to the flange assembly method
  • FIG. 21(b) corresponds to the thread assembly method
  • FIG. 21(c) corresponds to the welding assembly method.
  • the flange assembly method is to butt the two end flanges (61) and (62) of the two splice members (59) and (60) of the muffler, and the bolts (63) and the nut (64) are screwed together.
  • the thread assembling method is to dock the female end splicing piece (65) of the muffler with the male end splicing piece (66), and the internal thread end (67) of the female end splicing piece is engaged with the externally threaded end (68) of the male end splicing piece. Tight connection.
  • the welding assembly method is to dock the female end splice member (69) of the muffler with the male end splice member (70), and perform welding connection through the welding portion (71) of the male end splice member.
  • the annular groove is machined in the entire outer contour of the PAMB (72) frame, and the annular groove is realized by casting, turning, etc.; in the second step, the PAMB (72) is clamped by the positioning tool (73) to Inside the hollow tube (74), the fixed position is determined by the scale of the positioning tool (73); in the third step, the moving roller knife (75) head to the outer wall of the hollow tube (74) corresponds to the concave of the PAMB (72) The groove is positioned and a certain pressure is applied, at the same time, the positioning tool (73) clamps the PAMB (72) and the hollow tube (74) to rotate circumferentially together, so that the hollow tube (74) is formed inwardly with the protrusion and the internal PAMB.
  • the groove of the frame is tightly fitted.
  • the thin-walled hollow tube it can be processed by one-time rotation, for thicker hollow tubes, it needs multiple injections, or it can be squeezed at multiple points, without the need to tighten the entire ring, multi-point extrusion
  • the pressing method is also suitable for roll assembly of non-circular hollow tubes.
  • the ends of the semi-finished muffler (76) of the plurality of sets of acoustic metamaterial baffles that have been rolled are shrunk by means of a cuffing device (77).
  • Step 5 clean the burrs and refine the chamfer, most A finished muffler (78) that rolls a plurality of sets of acoustic metamaterial baffles is finally obtained.
  • the finite element simulation calculation method for the sound loss of the muffler Based on the commercial finite element software COMSOL Multiphysics 5.2, the acoustic-solid coupling frequency domain analysis module is used to establish the finite element simulation calculation model for the muffler sound loss.
  • the simulation model includes a "solid mechanical physical field” composed of a muffler external cavity structure and different types of baffle structures and a "pressure acoustic physics field" composed of a muffler internal air cavity, and the two physical field regions pass the acoustic-solid interface continuity. Conditions are coupled to each other. The boundary conditions of different types of baffle structures are defined as solid supports.
  • the incident acoustic wave is set as the plane acoustic wave (20-2000Hz frequency band, sweep frequency step is 10Hz) at the end of the inlet pipe, and the end surface of the inlet pipe and the outlet pipe are defined as the plane wave radiation boundary conditions, according to the sound pressure amplitude of the inlet pipe and the outlet pipe end face.
  • P I is the inlet tube sound pressure amplitude
  • P T is the outlet tube transmission sound pressure amplitude
  • Finite element simulation calculation method for muffler pressure loss Based on the commercial finite element software COMSOL Multiphysics 5.2, the fluid-solid coupling steady-state analysis module establishes the finite element simulation calculation model of the muffler pressure loss.
  • the simulation model includes a "line elastic material domain" composed of a muffler external cavity structure and different types of baffle structures and a "fluid domain” composed of a muffler internal air cavity, and the two domains are coupled to each other through a fluid-solid interface continuity condition. .
  • the boundary conditions of different types of baffle structures are defined as solid supports. Different inlet flow rates are set at the end of the inlet pipe, and the outlet pipe end face is defined as the outlet boundary condition.
  • the pressure drop of the muffler is calculated according to the total pressure of the inlet pipe and the outlet pipe end face (Pressure Drop, abbreviated as PD):
  • P in is the inlet full pressure and P out is the outlet full pressure.
  • the finite element simulation calculation method for the heat transfer efficiency of the muffler based on the acoustic finite element software COMSOL Multiphysics 5.2, the acoustic-solid coupling, fluid-solid coupling and fluid heat transfer physics, the flow velocity distribution calculated by the acoustic-solid coupling and fluid-solid coupling physics field is taken as Flow field input conditions for fluid heat transfer physics.
  • the wall temperature of the outer cavity of the muffler is set to a constant value as a heat source, and the initial internal temperature value of the muffler is set to 293.15 K (room temperature), and the other walls are set to adiabatic boundaries.
  • a specific inlet flow rate and a plane acoustic wave excitation of a particular frequency and amplitude are applied to the muffler inlet tube section and the muffler outlet tube section is set to a non-reflow boundary.
  • the time history solver is used to calculate the average temperature value of the cross section of the muffler outlet pipe.
  • Acoustic impedance tube test test method for sound transmission loss of muffler the sound transmission loss of the muffler is measured by a four-microphone single load method in the acoustic impedance tube, and the muffler is respectively connected through the inlet transition tube and the outlet transition tube
  • the sound tube is connected to the transmission sound tube, and a sound source is placed on one side of the incident sound tube, and the sound absorption tip is placed at the end of the transmission sound tube.
  • the incident acoustic wave, the reflected acoustic wave and the transmitted acoustic wave are decomposed by two pairs of microphones respectively placed on the inlet transition pipe and the exit transition pipe, and the sound transmission loss of the muffler is obtained according to the transfer matrix equation of the muffler (Munjal ML, Acoustics of ducts and mufflers , Wiley, 1987.).
  • Embodiment 1 Basic Acoustic Metamaterial Block Silencer
  • the frame of the basic type PAMB (14) shown in Fig. 2 is integrally formed by laser cutting using SPCC cold-rolled steel sheet, and the film is adhered on one side thereof and perforated, and the basic type PAMB is positioned in the expansion chamber through the sleeve (12). Internally, the outer cavity of the muffler is assembled by flange connection.
  • the expansion chamber (12) has a length of 250 mm and an inner diameter of 46 mm;
  • the inlet tube (11) has a length of 15 mm and an inner diameter of 10 mm;
  • the outlet tube (13) has a length of 15 mm and an inner diameter of 10 mm;
  • the muffler has a uniform wall thickness and a thickness of 3 mm;
  • the distance between the basic PAMB and the entrance port of the expansion chamber is 150 mm.
  • the outer cavity material of the muffler is 6063 grade aluminum alloy.
  • the basic PAMB (14) has a circular ring shape with an outer diameter of 46 mm, an inner diameter of 40 mm and a thickness of 2 mm.
  • the outer diameter of the hole-constrained body is 16 mm, the diameter of the constraining body hole is 10 mm, and the thickness of the perforated film is 0.05. Mm, the diameter of the upper through hole is also 10mm; the double-arm connecting rod between the hole-binding body and the frame has a rectangular cross section, a width of 3 mm and a thickness of 2 mm.
  • the frame, the perforated binding body and the double-arm connecting rod are made of the same material, all of which are SPCC cold-rolled steel; the perforated film is made of polyetherimide.
  • the outer cavity of the muffler and the basic type PAMB (14) in the finite element model are set as "solid mechanics physics field", and the inner air cavity of the muffler is set as "pressure acoustic physics field”.
  • the boundary condition of the basic PAMB (14) is defined as a fixed branch.
  • the incident acoustic wave is arranged on the end surface of the inlet pipe (11) as a plane acoustic wave, and the end faces of the inlet pipe (11) and the outlet pipe (13) are defined as plane wave radiation boundary conditions, so as to avoid the multiple reflection of the sound wave affecting the calculation result.
  • the incident acoustic wave P I excites the PAMB to produce a reflected acoustic wave P R and a transmitted acoustic wave P T .
  • the sound transmission loss of the basic acoustic super material block muffler is tested by the four-microphone single load method.
  • the schematic diagram of the test system is shown in Fig. 5.
  • the acoustic impedance tube is mainly composed of an incident acoustic tube (18) and a transmissive acoustic tube (19), and a sound source (17) is disposed at the end of the incident acoustic tube (18), which generates a broadband white noise excitation sound wave at the entrance transition tube.
  • the microphone (21) on (21) has been developed into a plane acoustic wave whose wavefront amplitude tends to be consistent.
  • the sound wave passes through the muffler to be tested (23) and enters the exit transition tube (22), and finally enters the transmission sound tube (19).
  • a sufficiently long sound absorbing tip (20) is placed at the rear end of the transmission acoustic tube (19) to minimize the influence of multiple reflections of sound waves on the test results.
  • there are four microphone fixed terminals (24) with a microphone (25) inserted (Model 4187, Brüel& ), two pairs are listed above the inlet transition tube (21) and the outlet transition tube (22).
  • the incident acoustic wave, the reflected acoustic wave and the transmitted acoustic wave are decomposed by two pairs of microphones, and the sound transmission loss of the muffler is obtained according to the transfer matrix equation of the muffler.
  • a fluid-solid coupling computational finite element simulation model consisting of a "fluid domain” consisting of a muffler external cavity and a basic PAMB (14) and a "fluid domain” formed by an internal air cavity of the muffler is established.
  • the boundary condition of the basic PAMB (14) is defined as a fixed branch.
  • the inlet flow rates are set at the end faces of the inlet pipe (11) to be 1 m/s, 2 m/s, 5 m/s, 10 m/s, 15 m/s, 20 m/s, 25 m/s and 30 m/s, respectively, and an outlet pipe (13) is defined.
  • the physics field of "acoustic-solid coupling" and “fluid heat transfer” is added, and the flow velocity distribution calculated by the acoustic-solid coupling and fluid-solid coupling physics is used as the flow field of the fluid heat transfer physics field.
  • the wall temperature of the outer cavity of the muffler is set to 303.15K, and the initial temperature of the muffler is set to 293.15K.
  • the other walls are set to adiabatic boundaries.
  • the inlet flow rate applied to the cross section of the muffler inlet tube was 5 cm/s, the amplitude of the incident plane acoustic wave was 1 Pa, the frequency was 200 Hz, and the cross section of the muffler outlet tube was set to have no reflow boundary.
  • the time history solver is used to calculate the average temperature value of the cross section of the muffler outlet pipe.
  • the following three types of muffler, the same aperture perforated block muffler, the equivalent sum perforated area microperforated block muffler and the non-block muffler were prepared using the basic acoustic super material baffle muffler described in Example 1, and the pass was measured. Two performance indicators of sound loss and pressure loss.
  • the perforated baffle (15) has a circular outer shape, an outer diameter of 46 mm, an inner diameter of 10 mm, and a thickness of 0.75 mm; the material is SPCC cold-rolled steel; the microperforated baffle (16) has an outer diameter of 46 mm and a thickness of 0.75.
  • Mm the inner central region is distributed with 25 micropores with a diameter of 2 mm, and the center distance of the micropores is 7 mm; the material is also SPCC cold rolled steel.
  • the surface densities of these three kinds of flaps were 5.67 kg/m 3 , and the perforation rate (the area of the through holes/the total area of the flaps) was 4.73%.
  • Fig. 4 is a comparison diagram of the finite element simulation calculation results of the sound absorbing loss of the above muffler.
  • the dotted line There should be no block muffler results, the dotted line corresponds to the result of the perforated block muffler, the dotted line corresponds to the microperforated block muffler result, and the solid line corresponds to the basic acoustic super material block muffler result.
  • the basic type acoustic super material block muffler according to Embodiment 1 of the present invention is directed to the low frequency first-order sound transmission loss valley, and utilizes the total reflection vibration mode generated by the PAMB sound wave excitation at the corresponding frequency of the low valley to efficiently reflect the sound wave and significantly improve the sound wave.
  • the value of the sound transmission loss near the frequency is higher than 10 dB in the continuous low and medium frequency bands of 50 to 1300 Hz, especially at 460 Hz, which is about 30 dB higher than that of the perforated block muffler.
  • FIG. 6 corresponds to the result of the no-block muffler;
  • Figure 6 (b) corresponds to the result of the perforated block muffler;
  • Figure 6 (c) corresponds to the result of the micro-perforated block muffler;
  • Figure 6 (d) corresponds to the basic acoustic super material Block muffler results.
  • the simulation results agree well with the experimental results, which indicates that the simulation model is correct and can be used to analyze the microscopic mechanism of the sound loss characteristics of the muffler. It also shows that the simulation model is suitable for the muffling frequency band of the acoustic super material block muffler. design.
  • Figure 8 is a comparison of the pressure loss of the different inlet air flow rates of the above muffler.
  • the circle mark corresponds to the result of the no-block muffler
  • the square mark corresponds to the result of the perforated block muffler
  • the triangle mark corresponds to the result of the micro-perforated block muffler
  • the star mark corresponds to the result of the basic type acoustic super material block muffler.
  • the pressure loss of the micro-perforated baffle muffler is the largest among the four under different input flow rate input conditions
  • the basic acoustic super material baffle muffler is the second
  • the non-stop muffler has the lowest pressure loss.
  • the inlet flow rate of the airflow piping system is less than 10 m/s. At this time, the pressure loss of the four muffler is small, and both are below 200 Pa.
  • Fig. 9 is a view showing the comparison of the heat transfer efficiency of the basic acoustic metamaterial baffle muffler and the equivalent aperture perforated baffle muffler according to Embodiment 1 of the present invention.
  • the dotted line corresponds to the result of the perforated block muffler
  • the solid line corresponds to the result of the basic type acoustic super material block muffler.
  • the basic acoustic supermaterial baffle muffler has a significantly higher heat transfer efficiency than the equivalent bore perforated baffle muffler, and its outlet temperature reaches a steady state value in a shorter time.
  • Figure 7 is a velocity direction distribution of air masses in the interior chamber of the muffler.
  • Figure 7 (a) corresponds to the result of the no-block muffler;
  • Figure 7 (b) corresponds to the result of the perforated block muffler;
  • Figure 7 (c) corresponds to the result of the micro-perforated block muffler;
  • Figure 7 (d) corresponds to the basic acoustic super material Block muffler results.
  • the black arrow indicates the direction of incidence of the sound wave. It can be clearly seen that the basic acoustic super-material baffle muffler has obvious acoustic vortex in the front and rear regions of the baffle, which is obviously different from other types of muffler.
  • the non-block muffler only the sound wave reflection phenomenon occurs in the near wall surface area at the outlet end, and the sound wave appears in the perforated block muffler.
  • the area of reflection is advanced, and the microperforated baffle muffler is closer to the exit end than the perforated baffle muffler.
  • the acoustic reflection area of the acoustic metamaterial baffle muffler appears at the upstream end of the acoustic metamaterial baffle, and the entire muffler chamber is dominated by back-propagating sound waves.
  • Example 2 Muffler with two sets of acoustic metamaterial baffles
  • the two-stage PAMB-containing muffler according to Embodiment 2 of the present invention is based on the basic acoustic super-material block muffler described in Embodiment 1, and is further configured by installing a set of PAMB.
  • the structural dimensions and material composition of the two groups of PAMB (30) and (31) are not identical, respectively, for different muffling trough bands.
  • the first group of PAMB (30) has a circular frame with an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; the outer diameter of the hole-constrained body is 18 mm, and the diameter of the constraining body hole is 12 mm; The thickness is 0.05 mm, and the diameter of the through hole is also 12 mm; the double-arm connecting rod between the hole-binding body and the frame has a rectangular cross section, a width of 3 mm, and a thickness of 2 mm.
  • the frame of the second group PAMB (31) is also circular, with an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; an outer diameter of the hole-constrained body is 16 mm, and a diameter of the constraining body hole is 10 mm; the thickness of the perforated film The diameter of the through hole is also 10 mm; the double-arm connecting rod between the hole-constrained body and the frame has a rectangular cross section, a width of 3 mm and a thickness of 2 mm.
  • the frame of the two groups of PAMB, the hole-constrained body and the material of the double-arm connecting rod are the same, all of which are SPCC cold-rolled steel; the material of the perforated film is polyetherimide.
  • FIG. 11 is a cross-sectional view showing the structure of a two-stage equivalent aperture perforated shutter muffler corresponding to the two-stage PAMB-containing muffler according to Embodiment 2 of the present invention.
  • the through hole sizes of the two inner perforated flaps (32) and (33) correspond to the two sets of PAMBs (30) and (31), respectively.
  • the perforated baffle (32) has a circular outer shape, an outer diameter of 46 mm, an inner diameter of 12 mm, and a thickness of 0.75 mm; the perforated baffle (33) is also annular, having an outer diameter of 46 mm, an inner diameter of 10 mm, and a thickness of 0.75mm; the materials of the two sets of perforated baffles are all SPCC cold rolled steel.
  • the surface density of the first group of sheets (30) and (32) was 5.49 kg/m 3 , and the perforation rate was 6.81%; the surface density of the second group of sheets (31) and (33) was 5.67 kg/ m 3 , the perforation rate was 4.73%.
  • the outer cavity material of the muffler is 6063 grade aluminum alloy.
  • FIG. 12 is a comparison diagram of simulation results of sound transmission loss of a muffler comprising two sets of PAMBs and a muffler comprising two sets of equal aperture perforated baffles according to Embodiment 2 of the present invention.
  • the solid line corresponds to the muffler results with two sets of PAMB
  • the dashed line corresponds to the results of two sets of perforated block muffler.
  • Embodiment 3 sound absorbing material closed impedance composite muffler
  • the sound-absorbing material closed-resistance composite muffler composed of two layers of PAMB intermediate-filled sound absorbing material according to the second embodiment of the present invention comprises a set of sound-absorbing material sealed impedance composite type baffle (35). It is composed of two layers of PAMB sandwiched by sound absorbing material. Wherein, the first layer of PAMB (including the frame (37) and the perforated film (36)) and the second layer of PAMB (including the frame (41) and the perforated film (42)) are connected by a bracket (40), and the bracket (40) is laid around the periphery.
  • the annular coating film (39) is filled with a sound absorbing material (38) between the annular coating film (39) and the inner wall surface of the muffler cavity (34).
  • the structural size and material composition of the muffler outer cavity (34) are the same as those in the first embodiment.
  • the first layer PAMB has a circular ring shape, an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; an outer diameter of the hole-constrained body is 16 mm, a diameter of the constraining body hole is 10 mm; and a thickness of the perforated film is 0.05 mm.
  • the diameter of the through hole is also 10 mm; the double-arm connecting rod between the hole-binding body and the frame has a rectangular cross section, a width of 3 mm and a thickness of 2 mm.
  • the frame of the second layer PAMB is also circular, with an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; an outer diameter of the hole-constrained body is 11 mm, a diameter of the constraining body hole is 5 mm; and a thickness of the perforated film is 0.05 mm.
  • the diameter of the through hole is also 5 mm; the double-arm connecting rod between the hole-binding body and the frame has a rectangular cross section, a width of 3 mm and a thickness of 2 mm.
  • the two-layer PAMB has the same material as the frame, the hole-constrained body and the double-arm connecting rod, all of which are SPCC cold-rolled steel; the perforated film is made of polyetherimide.
  • the bracket (40) is composed of two support rods, which are 50 mm long, 3 mm wide and 2 mm thick.
  • the annular coating film (39) has a thickness of 0.038 mm and the material is a polyetherimide.
  • the sound absorbing material (38) is glass fiber cotton with a bulk density of 9.6 kg/m 3 , a flow resistance of 19,000 Nsm -4 and a filling length of 50 mm.
  • FIG. 14 is a sound transmission loss test test result of a sound absorbing material closed-resistance composite muffler composed of two layers of PAMB intermediate-filled sound absorbing materials and two mufflers without PAB intermediate sound-absorbing materials according to Embodiment 3 of the present invention.
  • the solid line corresponds to the result of the closed-impedance composite muffler of the sound absorbing material
  • the broken line corresponds to the muffler result of the two layers of PAMB without filling the sound absorbing material.
  • the sound absorbing material is closed to the impedance composite muffler at full frequency. There is no obvious noise reduction and collapse in the segment, and the overall noise reduction effect is excellent.
  • Embodiment 4 three-dimensional stereotype super material block muffler
  • the frame (45) of the three-dimensional stereoscopic super material baffle muffler according to Embodiment 4 of the present invention is not in the same plane as the hole-constrained body (46), and is separated by a certain distance and connected by tilting.
  • the rods (47) are rigidly connected, and the film (48) is wrapped in a circular shape on the sides of the frame (45) and the restraining body (46).
  • the structural size and material configuration of the muffler outer cavity (43) are the same as those in the first embodiment.
  • the frame (45) of the three-dimensional stereotype PAMB has a circular shape, an outer diameter of 46 mm, an inner diameter of 40 mm, and a thickness of 2 mm; an outer diameter of the hole-constraining body (46) is 16 mm, and a diameter of the constraining body hole is 10 mm; a perforated film (48) has a thickness of 0.05 mm, and the diameter of the upper through hole is also 10 mm; the double-armed inclined connecting rod between the hole-constrained body and the frame has a rectangular cross section, a width of 3 mm, a thickness of 2 mm, and an axial vertical height of 20 mm.
  • the frame (45), the perforated binding body (46) and the inclined connecting rod (47) are of the same material and are all SPCC cold-rolled steel; the film (48) is made of polyetherimide.
  • FIG. 16 is a comparison diagram of simulation results of sound transmission loss of a three-dimensional stereo type super-material block muffler and a non-block muffler according to Embodiment 4 of the present invention.
  • the solid line corresponds to the result of the three-dimensional stereoscopic super material block muffler
  • the dotted line corresponds to the result of the no-block muffler.
  • the effective muffling frequency of the three-dimensional stereo type super material baffle muffler appears near 400 Hz, and the sound transmission loss is improved by about 3 to 5 dB compared with the non-stop muffler.
  • This embodiment is especially suitable for a sound-damping pipeline with a small diameter.
  • the three-dimensional stereotype PAMB can significantly improve the vibration area of the membrane and ensure a good low-frequency noise reduction effect.
  • the sandwich type PAMB according to Embodiment 5 of the present invention is constructed by attaching two layers of frames (50) and (51) to the left and right sides of the perforated film (52) and clamping the perforated film (52). .
  • the configuration of this embodiment can improve the working stability of the PAMB due to the fastening of the perforated film on both sides, making it suitable for high flow rate, strong impact flow and the like, such as the processing of transient impulse noise generated by the switch of the pneumatic valve.
  • Embodiment 6 tilt type acoustic metamaterial block muffler
  • the inclined PAMB (54) is placed obliquely at an angle ⁇ on the inner wall surface of the muffler outer cavity (53).
  • the structural size and material composition of the muffler outer cavity (53) are the same as those in the first embodiment.
  • the tilt type PAMB (54) has an installation tilt angle of ⁇ and an axial cross-sectional projection size similar to that of the basic type PAMB (14) shown in Embodiment 1.
  • the frame of the inclined PAMB (54), the hole-constrained body and the connecting rod are made of the same material, all of which are SPCC cold-rolled steel; the thickness of the film is 0.05 mm, and the material is polyetherimide.
  • FIG. 19 is a comparison diagram of sound transmission loss test results of a tilt type acoustic metamaterial block muffler including different tilt angles PAMB according to Embodiment 6 of the present invention.
  • the smaller the installation inclination angle ⁇ the more the noise reduction peak of the PAMB acts toward the low frequency, that is, when the installation inclination angle ⁇ is reduced from 45° to 30°, the noise reduction peak moves from 600 Hz to 450 Hz, and the sound transmission loss in other frequency bands
  • the change is not big.
  • the configuration of this embodiment is very suitable for the case where the pipe diameter is small and the flow demand is high.
  • Embodiment 7 PAMB array block muffler
  • FIG. 20 is a schematic structural diagram of a PAMB array block muffler composed of a plurality of PAMB in-plane arrays according to Embodiment 7 of the present invention.
  • the PAMB array blank (56) includes a plurality of PAMB units having the same or different structural dimensions and a perforated film (58) corresponding thereto.
  • the configuration described in this embodiment can ensure that the PAMB array flap has sufficient bending rigidity to facilitate the installation of the flap inside the hollow expansion chamber of the large-size section.
  • Embodiment 8 Assembly method of three acoustic metamaterial baffle muffler
  • Figure 21 is a schematic view showing the assembly structure of the flange assembly, the screw assembly and the welding assembly acoustic super material block muffler according to the embodiment 8 of the present invention.
  • 21(a) corresponds to the flange assembly method
  • FIG. 21(b) corresponds to the thread assembly method
  • FIG. 21(c) corresponds to the welding assembly method.
  • the flange assembly method is to butt the two end flanges (61) and (62) of the two splice members (59) and (60) of the muffler, and the bolts (63) and the nut (64) are screwed together.
  • the thread assembling method is to dock the female end splicing piece (65) of the muffler with the male end splicing piece (66), and the internal thread end (67) of the female end splicing piece is engaged with the externally threaded end (68) of the male end splicing piece. Tight connection.
  • the welding assembly method is to dock the female end splice member (69) of the muffler with the male end splice member (70), and perform welding connection through the welding portion (71) of the male end splice member.
  • Embodiment 9 A process flow of a roll processing acoustic super material block muffler
  • the process flow of a roll-pressing acoustic super material baffle muffler according to Embodiment 9 of the present invention is shown in FIG. 22, and is divided into five steps.
  • the annular groove is machined in the entire outer contour of the PAMB (72) frame, and the annular groove is realized by casting, turning, etc.
  • the PAMB (72) is clamped by the positioning tool (73) to Inside the hollow tube (74), the fixed position is determined by the scale of the positioning tool (73);
  • the moving roller knife (75) head to the outer wall of the hollow tube (74) corresponds to the concave of the PAMB (72)
  • the groove is positioned and a certain pressure is applied, at the same time, the positioning tool (73) clamps the PAMB (72) and the hollow tube (74) to rotate circumferentially together, so that the hollow tube (74) is formed inwardly with the protrusion and the internal PAMB.
  • the groove of the frame is tightly fitted.
  • the thin-walled hollow tube it can be processed by one-time rotation, for thicker hollow tubes, it needs multiple injections, or it can be squeezed at multiple points, without the need to tighten the entire ring, multi-point extrusion
  • the pressing method is also suitable for roll assembly of non-circular hollow tubes.
  • the ends of the semi-finished muffler (76) of the plurality of sets of acoustic metamaterial baffles that have been rolled are shrunk by means of a cuffing device (77).
  • the burr is cleaned and the chamfer is refined, and finally a finished muffler (78) for rolling a plurality of sets of acoustic metamaterial baffles is obtained.

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Abstract

一种消声器，其包括入口管（1）、出口管（3）、入口管（1）与出口管（3）之间的中空膨胀腔（2）、以及在所述的中空膨胀腔（2）内部截面上竖向或倾抖设置有含通孔的声学超材料挡片（4）。所述的含通孔的声学超材料档片（4）包含边框（8），在所述边框（8）内设置有与边框刚性连接的约束体（9），在边框（8）表面上覆盖有薄膜（6），在所述约束体（9）和薄膜（6）上均设置有通孔。还涉及一种改进的抗性消声器，其不仅能有效避免传统抗性消声器的驻波消声低谷的出现，还能够在结构紧凑的前提下具有优良的低频消声效果；还涉及一种改进的阻性消声器，解决传统阻性消声器中吸声材料与通过流体直接接触的问题；还涉及一种利用含通孔的声学超材料档片的振动提高孔两侧流体介质传热效率的消声器。另外，还提供了调频及制备含通孔的声学超材料挡片的方法及装配所述消声器的方法。

Description

含通孔的声学超材料挡片的消声器及其制备和装配方法 技术领域
本发明涉及一种可定制有效消声频段、扩展低频消声带宽、流体通过阻力小且能够增强流体传热效率的含通孔的声学超材料挡片的消声器，属于声学器件领域。
背景技术
对于气体或液体介质通过管道产生的噪声，例如工业通流管道、建筑新风系统管路、流体机械动力设备的进排气管、空调冰箱等制冷家电的冷媒传送管以及各类高压、高温及高速排气放空末端等，通常的解决方法是安装消声器装置，在保证足量流体顺利通过的同时，有效降低通过的噪声量级。
目前，消声器按照工作原理和结构形式主要分为三类：抗性消声器、阻性消声器和阻抗复合式消声器。抗性消声器主要通过管道声学特征的突变，例如扩张、收缩或旁通支路等，将部分声波反弹达到消声目的；阻性消声器通常采用管道内壁加衬的吸声材料，例如泡沫、纤维棉等多孔材料，将管道内的噪声在传播过程中不断吸收；阻抗复合式消声器则兼具抗性和阻抗消声器的结构特点，其中研究及应用最广的结构形式是在膨胀腔内沿轴向安装穿孔或微穿孔管，并在穿孔管与消声器壁面间空隙填充吸声材料。该类消声器能够同时利用突变结构反弹声波，利用穿孔管与消声器壁面构成的腔体共振特性吸收特定频段噪声，以及利用填充的吸声材料吸收透过的高频声波。
由于抗性消声器的有效消声频段与其结构尺寸存在反比关系，对于波长尺度大、传播距离远的低频噪声，相应的抗性消声器结构尺寸需做到足够大。例如，针对空气介质传播100赫兹噪声设计的简单膨胀腔抗性消声器，其膨胀腔长度至少应达到所需抑制噪声波长的四分之一，即约85厘米，才能起到有效的消声作用。此外，为了弥补单节抗性消声器的驻波消声低谷问题，即当膨胀腔长度为噪声波长的二分之一及其整数倍时，消声量近于零，现有技术是在膨胀腔内部连接插入管或将多节膨胀腔串联。因此，该类消声器尺寸庞大、结构笨重，难以满足实际工程对安装空间要求高的场合(中国公开专利：CN202707196U、CN105569775A、CN105518269A、CN103382874A，美国公开专利：US7497301B2、US7798286B2、US7942239B2、US8617454B2)。而阻性消声器由于采用了吸声材料，一方面使其有效消声频段局限在高频，另一方面 吸声材料与通过流体直接接触，在工作过程中不可避免的吸湿、成坨或脱落，影响使用寿命。阻抗复合式消声器虽兼具抗性和阻性特点，但也无法避免吸声材料暴露在管道流体中的问题，限制了其应用在高温、潮湿、流速大、洁净要求高的场合，而且内部结构复杂，生产制造和检修维护成本高(中国公开专利：CN204921097U、CN104564285A，美国公开专利：US6332511B1、US8146574B2)。
最近二十年，声学领域具有颠覆性突破的研究成果首推局域共振型声学超材料(Acoustic Metamaterial.2000年，Zhengyou Liu等，Locally Resonant Sonic Materials，Science 289,1734.)。作为一种人工设计的声学微结构，其在特定频率声波激励下表现出“负动态质量”及/或“负体积模量”特定状态，使得人们可以利用结构尺寸远小于声波波长的轻薄结构有效操控低频声波的传播。2015年，中国专利申请CN105090670A将声学超材料概念与具体消声器件相结合，公开了一种薄膜声学超材料消声器。其在消声器管壁侧面安装若干薄膜声学超材料单胞，利用声学超材料单胞在管道噪声激励下产生的振动模式消减特定频率的噪声量级。然而，由于该发明限定声学超材料单胞的表面与管道中的噪声入射方向平行，虽一定程度上减少了对通过流体的阻力，但其有效消声带宽极窄，该发明实施例所述的消声器工作带宽仅为十几赫兹，难以胜任低频宽带噪声工况。
综上所述，在管道消声工程领域亟需创造结构紧凑、低频宽带消声好、消声频率调控准确方便、通流阻碍小、工作性能稳定、服役时间长的消声器。
发明内容
本发明解决的技术问题是提供一种能够克服现有薄膜声学超材料消声器存在的低频消声带宽窄问题的技术方案，提供一种沿管道流向截面竖向或倾斜安装的、含通孔的声学超材料挡片的消声器(Baffled Acoustic Metamaterial Silencer，简称“BAMS”)，其低频消声效果好于同等孔径穿孔挡片和同等总和穿孔面积微穿孔挡片消声器。而且含通孔的声学超材料挡片(Perforated Acoustic Metamaterial Baffle，以下简称“PAMB”)上的通孔尺寸可根据通流需求和消声频段要求进行设计，在保证足量热流、气流或液流顺利通过的同时，有效削减噪声量级。
本发明还提供一种改进的抗性消声器技术方案，其通过设计安装在传统抗性消声器内部截面上的PAMB的工作频段涵盖原消声器的驻波低谷频段，显著提高该频段的传声损失性能，拓宽消声带宽。由于并不是依靠消声器的结构尺 寸与消声波长相匹配的消声原理，而是基于PAMB的局域共振机理，进一步地可以在消声器的结构做到足够紧凑的前提下，仍然获得优良的低频消声效果。
本发明还提供一种改进的阻性消声器技术方案，其采用一层较厚(厚度5毫米以上)或多层PAMB将吸声材料封闭，通过与吸声材料阻抗匹配的薄膜传递声能，进而转变为热能消耗，有效解决了传统阻性消声器的吸声材料与通过流体直接接触问题。
本发明还提供一种增强流体传热效率的消声器技术方案，其一方面通过PAMB在声波激励下产生的振动，提高通孔两侧介质的温差及热量传导速率；另一方面，当有流体通过时，PAMB的薄膜产生的流致振动可以增加热源贴壁处的流体湍流度，阻碍热边界层和速度边界层的形成，加快换热效率。
本发明还提供了PAMB的调频及制备方法以及消声器的装配方法。通过改变PAMB边框、约束体和薄膜的结构尺寸及材料构成调节PAMB的工作频段；采用一体成型或预制件组装方法进行PAMB的制备，并利用辊压装配、过盈配合、间隙焊接、组合拼接等工艺方法进行消声器的装配。
本发明的技术方案如下：
一种消声器，其包括入口管、出口管、入口管与出口管之间的中空膨胀腔、以及在所述的中空膨胀腔内至少一个截面上竖向或倾斜设置有PAMB。优选在沿管道流向的横截面上安装PAMB。
所述PAMB包含边框，在所述边框内设置至少一个约束体，在边框两侧表面的至少一个表面上覆盖有薄膜，所述约束体和薄膜上均设置有至少一个通孔。
所述中空膨胀腔的截面形状根据消声器的安装空间及消声器膨胀比等参数要求确定；优选中空膨胀腔的横截面形状为圆形、椭圆形、长方形、正多边形，中空膨胀腔的纵截面形状为矩形、锥形、波状。
所述边框为中空结构，其外轮廓形状与中空膨胀腔的截面形状一致；约束体设置在边框的内部，约束体和边框通过至少一根连接杆刚性连接；薄膜外周区域贴合边框表面，内部区域受约束体约束；优选所述约束体及连接杆与边框齐平，此时连接杆成为约束体的一部分，用于约束薄膜振动。
所述约束体和薄膜的通孔大小根据通流需求(通孔面积＝流量/流速)以及消声频段两方面共同确定；优选所述约束体和薄膜上的通孔的孔径大于2毫米。
所述约束体的通孔面积是依据如下方式确定的：对通流效率要求较高的场合，选择大的约束体通孔面积；对消声频段倾向于低频的场合，在保证边框和薄膜的几何尺寸和材料参数不变的前提下，选择小尺寸的通孔孔径。
所述约束体和薄膜上孔的形状、位置和大小相同或不同；优选所述通孔的形状、位置和大小相同；优选所述通孔的形状为任意几何形状；更优选所述几何形状为对称规则形状，进一步优选为圆形、椭圆形、正多边形。
所述约束体与薄膜的接触区域为线或面；优选接触形状是对称规则的几何形状；更优选所述的几何形状为圆形、椭圆形、正多边形。
所述约束体的数量主要根据消声频段而定，约束体的数量越多则意味着薄膜可振动面积越少，消声器的消声频段越趋向高频。
一种改进的抗性消声器，其特征在于，在传统抗性消声器的内部截面上设置有至少一个PAMB，优选PAMB的工作频段涵盖所述传统抗性消声器的驻波消声低谷频段；更优选所述PAMB的峰值工作频率与各阶驻波频率一致。
一种改进的阻性消声器，其特征在于，将吸声材料用一层或多层PAMB封闭，避免吸声材料与通过流体直接接触；优选所述一层PAMB的厚度大于5毫米；优选所述一层PAMB的边框两侧表面均覆盖有薄膜，两层薄膜内部填充与薄膜阻抗相匹配的多孔材料；优选两层薄膜的厚度及/或材料不同。当厚度及/或材料不同时，两层薄膜表现出不同的特征振动频率，有利于拓展工作带宽。优选所述多层PAMB通过支架定位，将一层不透薄膜包覆在支架外围，在不透薄膜与膨胀腔壁面之间的空腔内或者在两层薄膜中间填充与薄膜阻抗相匹配的多孔材料；优选不透薄膜的材料与PAMB的薄膜一样；优选所述多孔材料为玻璃纤维棉或开、闭孔泡沫。
一种增强流体传热效率的消声器，其特征在于，一方面通过PAMB在声波激励下产生的振动，提高通孔两侧介质的温差及热量传导速率；另一方面，当有流体通过时，PAMB的薄膜产生的流致振动可以增加热源贴壁处的流体湍流度，阻碍热边界层和速度边界层的形成，加快换热效率；其用于增强流体传热效率。
一种包含所述PAMB的阵列挡片，其由多个PAMB在面内方向阵列组合拼接而成；当需要宽频消声时，优选形成阵列挡片的各个PAMB的几何尺寸和材料参数不同，当需要窄带消声时，优选形成阵列挡片的各个PAMB的几何尺寸和材料参数相同。
所述PAMB的边框和约束体的材料为金属材料或非金属材料，优选金属材料为铝、铁、钢、铜，优选非金属材料为木材、陶瓷、橡胶、玻璃、石膏、水泥、高分子聚合物或复合纤维材料；所述薄膜的材料为高分子聚合物薄膜材料、金属薄膜材料或弹性薄膜材料，所述聚合物薄膜材料优选为聚醚酰亚胺膜、聚 氯乙烯膜、聚乙烯膜、所述金属薄膜材料优选铝及铝合金膜、钛及钛合金膜，所述弹性薄膜材料优选为橡胶膜、硅胶膜、乳胶膜。
一种消除传统抗性消声器的驻波消声低谷的方法，所述方法包括如下步骤：将含通孔的声学超材料挡片安装在传统抗性消声器的内部横截面上，并且使含通孔的声学超材料挡片的工作频段涵盖所述传统抗性消声器的驻波消声低谷频段；优选所述含通孔的声学超材料挡片的工作频段与低频的第一阶驻波频率一致。
一种调节所述消声器消声频段的方法，在消声器膨胀腔形状及尺寸不变的前提下，通过改变所述PAMB的边框、约束体及薄膜的结构尺寸和材料参数来实现调节PAMB的有效工作频段，提高消声器在该频段内的消声性能。
一种装配所述PAMB的方法，其特征在于，所述有孔约束体和边框采用一体成型技术制备得到，或者制造有孔约束体预制件和边框预制件，将有孔约束体预制件通过连接杆刚性连接到边框预制件上组成框架，之后将薄膜在自由伸展状态下覆盖在框架上，并进行固定连接，最后在薄膜上进行打孔；进一步地，为保证PAMB的工作稳定性，采用两层所述的框架将薄膜夹持在中间，并进行固定连接；优选通过铣削、铸造、冲压、激光切割或3D打印技术加工为一体成型的框架，或者通过铣削、铸造、冲压、激光切割或3D打印技术制造出有孔约束体预制件和边框预制件；优选固定连接为胶粘、热焊接或机械铆接。
一种装配所述消声器的方法，其特征在于，所述方法先通过定位工具将PAMB送至中空管内部既定位置，之后移动辊刀刀头到中空管外壁面对应位置并施加一定压力，将PAMB嵌于中空管中；对中空管进行两端收口成形。
一种装配所述消声器的方法，其特征在于，所述方法通过冲压或热装配的方法将PAMB装入中空管内，利用过盈配合的约束力将含通孔的声学超材料挡片固定于中空管的既定位置；对中空管进行两端收口成形。
一种装配所述消声器的方法，其特征在于，所述方法通过定位夹具将PAMB装入中空管内的既定位置，再利用超声波、激光、氩弧焊等工艺点焊固定PAMB，或者采用套筒、弹簧等结构定位PAMB；对中空管进行两端收口成形。
其中收口成形优选采用模具成型、旋压成型、出入口管焊接成型。
一种装配所述消声器的方法，其特征在于，通过铸造、车削、冲压工艺制造出两个或多个消声器拼接件，优选消声器拼接件是轴切对半式，在其中一半消声器拼接件既定位置安装固定PAMB后，扣合另一半消声器拼接件并合缝；优选安装固定PAMB的方法包括焊接、凹槽紧箍、套筒定位，优选合缝方式为 焊接、铆接、铰接、胶粘。
与现有技术相比，本发明的有益效果：
1)所述的消声器内部沿管道流向截面竖向或倾斜安装PAMB，其低频消声带宽及消声量均优于同等孔径穿孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和现有的贴壁面平行安装的薄膜声学超材料消声器等。
2)所述的PAMB不同于传统薄膜局域共振型声学超材料，其不需要安装配重质量块，不会发生配重质量块工作过程中意外脱落的情况，使得消声器的工作稳定性加强。
3)所述PAMB的通孔尺寸可根据通流需求和消声频段要求进行设计，在保证足量热流、气流或液流顺利通过的同时，有效削减噪声量级。通过设计插入传统抗性消声器横截面上的PAMB的工作频段与原消声器的驻波消声低谷相一致，显著提高驻波频率处的消声性能，拓宽消声带宽。替代传统的在膨胀腔内部安装插入管或将多节膨胀腔串联的技术方案，在不改变膨胀腔整体结构尺寸的前提下，彻底解决传统抗性消声器的驻波消声低谷问题。
4)所述的消声器内部采用一层较厚或多层PAMB将吸声材料封闭，通过薄膜传递声能进入吸声材料，进而转变为热能消耗。有效解决传统阻性消声器中吸声材料与通过流体直接接触的问题，避免吸声材料的吸湿、成坨及脱落现象的出现，显著延长使用寿命。
5)所述的消声器内部利用PAMB自身结构在声波激励下的振动，加快贴壁处的冷热空气交换过程，确保孔两侧介质的温差维持在较高量级，长时间保证较大的热量传导速率；当有流体通过时，PAMB的薄膜振动可以增加热源贴壁处的流体湍流度，阻碍热边界层和速度边界层的形成，加快对流换热效率。
6)所述的PAMB结构形式简单，批量化加工工艺成熟。所述的消声器内部结构形式简单，加工装配难度小，而且结构紧凑，适用于各类安装空间。
附图说明
图1为本发明声学超材料挡片消声器通用构型及其包含的一类PAMB结构示意图。
图2为本发明实施例1所述的基本型声学超材料挡片消声器结构示意图。
图3为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器和同等总和穿孔面积微穿孔挡片消声器的结构剖视图。
图4为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿 孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和无挡片消声器的传声损失有限元仿真计算结果对比图。
图5为采用四传声器单负载法测量消声器样件传声损失的声阻抗管测试系统示意图。
图6为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和无挡片消声器的传声损失试验测量结果与有限元仿真计算结果的对比图。
图7为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和无挡片消声器的腔内空气质点的速度方向分布图。
图8为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和无挡片消声器的不同入口空气流速的压力损失对比图。
图9为本发明实施例1所述的基本型声学超材料挡片消声器与同等孔径穿孔挡片消声器的传热效率对比图。
图10为本发明实施例2所述的含两组PAMB的消声器结构示意图。
图11为本发明实施例2所述的含两组PAMB的消声器和含两组同等孔径穿孔挡片的消声器结构剖视图。
图12为本发明实施例2所述的含两组PAMB的消声器和含两组同等孔径穿孔挡片的消声器的传声损失有限元仿真计算结果对比图。
图13为本发明实施例3所述的由两层PAMB中间填充吸声材料所构成的吸声材料封闭阻抗复合型消声器结构示意图。
图14为本发明实施例3所述的由两层PAMB中间填充吸声材料所构成的吸声材料封闭阻抗复合型消声器和两层PAMB中间不填充吸声材料的消声器的传声损失试验测试结果对比图。
图15为本发明实施例4所述的三维立体型声学超材料挡片消声器结构示意图。
图16为本发明实施例4所述的三维立体型声学超材料挡片消声器和无挡片消声器的传声损失有限元仿真计算结果对比图。
图17为本发明实施例5所述的三明治型PAMB的结构示意图。
图18为本发明实施例6所述的倾斜型声学超材料挡片消声器的结构示意图。
图19为本发明实施例6所述的包含不同倾斜角度PAMB的倾斜型声学超材料挡片消声器的传声损失试验结果对比图。
图20为本发明实施例7所述的由多个PAMB面内阵列组成的PAMB阵列挡片消声器的结构示意图。
图21为本发明实施例8所述的法兰装配、螺纹装配和焊接装配声学超材料挡片消声器的装配结构示意图。
图22为本发明实施例9所述的一种辊压加工声学超材料挡片消声器的工艺流程。
其中，1-入口管，2-膨胀腔，3-出口管，4-声学超材料挡片(PAMB)，5-框架，6-薄膜，7-薄膜孔，8-边框，9-约束体，10-约束体孔，11-实施例1所述的入口管，12-实施例1所述的膨胀腔，13-实施例1所述的出口管，14-实施例1所述的基本型PAMB，15-实施例1所述的与基本型PAMB同等孔径的穿孔挡片，16-实施例1所述的与基本型PAMB同等总和穿孔面积的微穿孔挡片，17-声源，18-入射声管，19-透射声管，20-末端吸音尖劈，21-入口过渡管，22-出口过渡管，23-待测消声器，24-传声器固定端子，25-传声器，26-支脚，27-实施例2所述的入口管，28-实施例2所述的膨胀腔，29-实施例2所述的出口管，30-实施例2所述的第1组PAMB，31-实施例2所述的第2组PAMB，32-实施例2所述的第1组穿孔挡片，33-实施例2所述的第2组穿孔挡片，34-实施例3所述的消声器外部腔体，35-实施例3所述的吸声材料封闭阻抗复合型挡片，36-实施例3所述的第1层PAMB的穿孔薄膜，37-实施例3所述的第1层PAMB的框架，38-实施例3所述的吸声材料，39-实施例3所述的环形包覆膜，40-实施例3所述2层PAMB之间的支架，41-实施例3所述第2层PAMB的框架，42-实施例3所述第2层PAMB的穿孔薄膜，43-实施例4所述的消声器外部腔体，44-实施例4所述的三维立体型PAMB，45-实施例4所述三维立体型PAMB的边框，46-实施例4所述三维立体型PAMB的有孔约束体，47-实施例4所述三维立体型PAMB的倾斜连接杆，48-实施例4所述三维立体型PAMB的穿孔薄膜，49-实施例5所述的三明治型PAMB，50-实施例5所述三明治型PAMB的第1层框架，51-实施例5所述三明治型PAMB的第2层框架，52-实施例5所述三明治型PAMB的穿孔薄膜，53-实施例6所述的消声器外部腔体，54-实施例6所述的倾斜型PAMB。55-实施例7所述的消声器外部腔体，56-实施例7所述的PAMB阵列挡片，57-实施例7所述PAMB阵列挡片的框架，58-实施例7所述PAMB阵列挡片的穿孔薄膜，59-实施例8所述法兰装配声学超材料挡片消声器的第1拼接件， 60-实施例8所述法兰装配声学超材料挡片消声器的第2拼接件，61-实施例8所述的第1拼接件端面法兰，62-实施例8所述的第2拼接件端面法兰，63-螺栓，64-螺母，65-实施例8所述螺纹装配声学超材料挡片消声器的母端拼接件，66-实施例8所述螺纹装配声学超材料挡片消声器的公端拼接件，67-实施例8所述的母端拼接件内螺纹端，68-实施例8所述的公端拼接件外螺纹端，69-实施例8所述焊接装配声学超材料挡片消声器的母端拼接件，70-实施例8所述焊接装配声学超材料挡片消声器的公端拼接件，71-实施例8所述公端拼接件的焊接区，72-实施例9所述的PAMB，73-实施例9所述的定位工具，74-实施例9所述的中空管，75-实施例9所述的辊刀，76-实施例9所述已辊压多组声学超材料挡片的半成品消声器，77-实施例9所述的收口装置，78-实施例9所述辊压多组声学超材料挡片的成品消声器。
具体实施方式
下面结合附图对本发明的具体实施方式进行说明。
图1是本发明所述的声学超材料挡片消声器的一种通用构型，其包含消声器外部腔体及内部多片竖向或倾斜放置的声学超材料挡片(PAMB)。其中，消声器外部腔体包括入口管(1)、出口管(3)及中空膨胀腔(2)、在所述的中空膨胀腔内多个截面上竖向或倾斜放置PAMB。以一个PAMB(4)为例，其包含边框(8)，在所述的边框内设置有与边框刚性相连的约束体(9)，在边框一侧表面上覆盖有薄膜(6)，并受内部约束体(9)约束，所述约束体(9)和薄膜(6)上分别设置有通孔(10)、(7)。
图2为本发明实施例1所述的基本型声学超材料挡片消声器，其内部仅含一组竖向放置的基本型PAMB(14)，消声器外部腔体包含入口管(11)、膨胀腔(12)和出口管(13)。
图3为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器和同等总和穿孔面积微穿孔挡片消声器的结构剖视图。
三种消声器外部腔体的结构及尺寸均相同，膨胀腔长度L＝250mm，内径D＝46mm；入口管长度L1＝15mm，内径d1＝10mm；出口管长度L2＝15mm，内径d2＝10mm；消声器壁厚均匀，厚度h＝3mm；每种挡片与膨胀腔入射端口的距离均为l1＝150mm。消声器外部腔体材料为6063牌号铝合金。
基本型PAMB(14)的边框为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为16mm，约束体孔的直径为10mm；穿孔薄膜 的厚度为0.05mm，其上通孔的直径亦为10mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。边框、有孔约束体以及双臂连接杆的材料相同，均为SPCC冷轧钢；穿孔薄膜的材质为聚醚酰亚胺。
穿孔挡片(15)为圆环形，外径为46mm，内径为10mm，厚度为0.75mm；材料为SPCC冷轧钢。
微穿孔挡片(16)的外径为46mm，厚度为0.75mm，内部中心区域分布25个直径为2mm的微孔，微孔中心距离为7mm；材料为SPCC冷轧钢。
三种挡片的面密度均为5.67kg/m3，穿孔率(通孔面积/挡片总面积)均为4.73％。
图4为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器和同等总和穿孔面积微穿孔挡片消声器和无挡片消声器的传声损失有限元仿真计算结果对比图。其中，虚线对应无挡片消声器结果，点线对应穿孔挡片消声器结果，点划线对应微穿孔挡片消声器结果，实线对应基本型声学超材料挡片消声器结果。对于无挡片消声器，其传声损失频谱在700Hz及1400Hz附近出现了明显的低谷，消声量几乎为零，这是由于膨胀腔的纵向尺寸L刚好等于入射声波半波长的整数倍。在膨胀腔内部放置穿孔挡片使得两个传声损失低谷分别移动到460Hz和1250Hz附近。对于微穿孔挡片消声器，其传声损失低谷的对应频率位于600Hz和1300Hz附近。本发明实施例1所述的基本型声学超材料挡片消声器针对低频的第一阶传声损失低谷，利用PAMB在该低谷对应频率的声波激励产生的全反射振动模式，高效反射声波，显著提高该频率附近的传声损失量值。如图4所示，基本型声学超材料挡片消声器的传声损失在50～1300Hz连续的低、中频段内均高于10dB，尤其在460Hz比穿孔挡片消声器高约30dB。
图5为采用四传声器单负载法测量消声器样件传声损失的声阻抗管测试系统示意图。声阻抗管主要由入射声管(18)和透射声管(19)组成，在入射声管(18)的端部安置声源(17)，其产生的宽频白噪声激励声波在到达入口过渡管(21)上的传声器(25)之前已经发展成波前幅值趋于一致的平面声波，声波经过待测消声器(23)后进入出口过渡管(22)，并最终进入透射声管(19)，在透射声管(19)的后端安置足够长的吸音尖劈(20)以尽量减少声波的多次反射对测试结果的影响。位于待测消声器(23)两侧，共有四个传声器固定端子(24)，其内插入传声器(25)(型号4187,Brüel&
Figure PCTCN2016090450-appb-000001
)，两两分列于入口过渡管(21)和出口过渡管(22)之上。该测试系统的有效测试频段为50 Hz～1600Hz，截止频率为1720Hz。
图6为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和无挡片消声器的传声损失试验测量结果与有限元仿真计算结果的对比图。其中，图6(a)对应无挡片消声器结果，其中实线为仿真结果，空心圆圈为试验结果；图6(b)对应穿孔挡片消声器结果，其中实线为仿真结果，空心圆圈为试验结果；图6(c)对应微穿孔挡片消声器结果，其中实线为仿真结果，空心圆圈为试验结果；图6(d)对应基本型声学超材料挡片消声器结果，其中实线为仿真结果，空心圆圈为试验结果。据图可知，仿真结果和试验结果的吻合程度良好，表明仿真模型计算正确，能用于分析消声器传声损失特性的微观机理，也表明该仿真模型适合于声学超材料挡片消声器的消声频段设计。
图7为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和无挡片消声器在460Hz频率声波激励条件下，消声器内部腔室空气质点的速度方向分布。其中，图7(a)对应无挡片消声器结果；图7(b)对应穿孔挡片消声器结果；图7(c)对应微穿孔挡片消声器结果；图7(d)对应基本型声学超材料挡片消声器结果。黑色箭头表示声波入射方向。可以明显看出，基本型声学超材料挡片消声器的挡片前后区域出现明显的声波涡旋，明显区别于其他类型的消声器。具体而言，对于无挡片消声器，其仅在出口端近壁面区域出现明显的声波反射现象，穿孔挡片消声器出现声波反射的区域提前，微穿孔挡片消声器相比于穿孔挡片消声器，出现声波反射的区域更接近出口端。声学超材料挡片消声器的声波反射区域出现在声学超材料挡片的上游端，整个消声器腔室内以反向传播的声波为主。
图8为本发明实施例1所述的基本型声学超材料挡片消声器、同等孔径穿孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和无挡片消声器的不同入口空气流速下的压力损失对比结果。其中，圆圈标记对应无挡片消声器结果，方形标记对应穿孔挡片消声器结果，三角标记对应微穿孔挡片消声器结果，星号标记对应基本型声学超材料挡片消声器结果。其中，微穿孔挡片消声器的压力损失在不同入射流速输入条件下，均为四者中最大，基本型声学超材料挡片消声器次之，而无挡片消声器的压力损失最小。通常气流管道系统入口流速多在10m/s以下，此时四种消声器的压力损失差别微小，且均在200Pa以下。
图9为本发明实施例1所述的基本型声学超材料挡片消声器与同等孔径穿孔挡片消声器的传热效率对比图。其中，虚线对应穿孔挡片消声器结果，实线 对应基本型声学超材料挡片消声器结果。可以明显看出基本型声学超材料挡片消声器的传热效率高于同等孔径穿孔挡片消声器，其出口温度以更短的时间达到稳态值。
值得指出的是，本发明实施例1所述的基本型声学超材料挡片消声器和同等孔径穿孔挡片消声器的内部挡片的通孔直径与入口管及出口管的直径相同，均为10mm。在如此大尺寸通孔条件下，普通的穿孔挡片消声器的通流散热效果已经足够理想，因此采用PAMB的声学超材料挡片消声器在传热效率上并没有与之拉开显著差距。但是随着挡片通孔尺寸的进一步缩小，或者入口流速的进一步降低，声学超材料挡片消声器内部放置的PAMB的振动幅度增大，能够更加有效地增加通孔两侧介质的交换速率，其在加强传热方面的优势便更能得到体现。
图10为本发明实施例2所述的含两组PAMB的消声器结构示意图。消声器外部腔体包含入口管(27)、膨胀腔(28)和出口管(29)，膨胀腔(28)内部竖直安装间隔一定距离的两组PAMB(30)和(31)，其结构尺寸及材料构成不完全相同，分别针对不同的消声低谷频段。
图11为本发明实施例2所述的含两组PAMB的消声器和含两组同等孔径穿孔挡片消声器的结构剖视图。其中，黑色箭头表示声波入射方向。两类消声器外部腔体的结构及尺寸均相同，膨胀腔长度L＝250mm，内径D＝46mm；入口管长度L1＝15mm，内径d1＝10mm；出口管长度L2＝15mm，内径d2＝10mm；消声器壁厚均匀，厚度h＝3mm；第1组PAMB(30)与膨胀腔入射端口的距离l1＝L/3，第2组PAMB(31)与膨胀腔出射端口的距离l2＝L/3。消声器外部腔体材料为6063牌号铝合金。
对于含两组PAMB的消声器，其内部的两组PAMB的结构尺寸及材料构成不完全相同。其中，第1组PAMB(30)的边框为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为18mm，约束体孔的直径为12mm；穿孔薄膜的厚度为0.05mm，其上通孔的直径亦为12mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。第2组PAMB(31)的边框同样为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为16mm，约束体孔的直径为10mm；穿孔薄膜的厚度为0.05mm，其上通孔的直径亦为10mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。两组PAMB的边框、有孔约束体以及双臂连接杆的材料相同，均为SPCC冷轧钢；穿孔薄膜的材质均为聚醚酰亚胺。
对于含两组与上述两组PAMB分别对应的同等孔径穿孔挡片消声器，其内部的两组穿孔挡片(32)和(33)的通孔尺寸分别与两组PAMB(30)和(31)对应。
其中，穿孔挡片(32)为圆环形，外径为46mm，内径为12mm，厚度为0.75mm；穿孔挡片(33)同样为圆环形，外径为46mm，内径为10mm，厚度为0.75mm；两组穿孔挡片的材料均为SPCC冷轧钢。
第1组挡片(30)和(32)的面密度均为5.49kg/m3，穿孔率均为6.81％；第2组挡片(31)和(33)的面密度均为5.67kg/m3，穿孔率均为4.73％。
图12为本发明实施例2所述的含两组PAMB的消声器和含两组同等孔径穿孔挡片消声器的传声损失仿真结果对比图。其中，实线对应含两组PAMB的消声器结果，虚线对应含两组穿孔挡片消声器结果。可以明显看出，含两组PAMB的消声器有效弥补了含两组穿孔挡片消声器分别位于400Hz和760Hz的两个驻波消声低谷，从而显著提高了低频有效消声带宽和消声量级。
图13为本发明实施例3所述的由两层PAMB中间填充吸声材料所构成的吸声材料封闭阻抗复合型消声器的结构示意图。吸声材料密封阻抗复合型挡片(35)由两层PAMB中间夹持吸声材料构成。其中，第1层PAMB(包含框架(37)和穿孔薄膜(36))与第2层PAMB(包含框架(41)和穿孔薄膜(42))通过支架(40)连接，支架(40)外围铺设环形包覆膜(39)，在环形包覆膜(39)与消声器腔体(34)内壁面间填充吸声材料(38)。
其中，消声器外部腔体(34)的结构尺寸及材料构成同实施例1。第1层PAMB的边框为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为16mm，约束体孔的直径为10mm；穿孔薄膜的厚度为0.05mm，其通孔的直径亦为10mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。第2层PAMB的边框同样为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为11mm，约束体孔的直径为5mm；穿孔薄膜的厚度为0.05mm，其通孔的直径亦为5mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。两层PAMB的边框、有孔约束体以及双臂连接杆的材料相同，均为SPCC冷轧钢；穿孔薄膜的材质均为聚醚酰亚胺。支架(40)由两根支撑杆组成，其长50mm，宽3mm，厚2mm。环形包覆膜(39)的厚度为0.038mm，材料为聚醚酰亚胺。吸声材料(38)为玻璃纤维棉，容重为9.6kg/m3，流阻率为19000Nsm-4，填充长度为50mm。
图14为本发明实施例3所述的由两层PAMB中间填充吸声材料所构成的吸 声材料封闭阻抗复合型消声器和两层PAMB中间不填充吸声材料的消声器的传声损失试验测试结果对比图。其中，实线对应吸声材料封闭阻抗复合型消声器结果，虚线对应两层PAMB中间不填充吸声材料的消声器结果。相比于两层PAMB中间不填充吸声材料的消声器，吸声材料封闭阻抗复合型消声器在全频段内无明显消声塌陷，整体消声效果优异。
图15为本发明实施例4所述的三维立体型声学超材料挡片消声器的结构示意图。其中，边框(45)与有孔约束体(46)不在同一平面内，二者相距一定距离并通过倾斜连接杆(47)刚性连接，薄膜(48)成圆台状包覆在边框(45)和约束体(46)的侧面。
其中，消声器外部腔体(43)的结构尺寸及材料构成同实施例1。三维立体型PAMB的边框(45)为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体(46)的外径为16mm，约束体孔的直径为10mm；穿孔薄膜(48)的厚度为0.05mm，其上通孔的直径亦为10mm；有孔约束体与边框之间的双臂倾斜连接杆为矩形截面，宽3mm，厚2mm，轴向垂直高度为20mm。边框(45)、有孔约束体(46)以及倾斜连接杆(47)的材料相同，均为SPCC冷轧钢；薄膜(48)的材质为聚醚酰亚胺。
图16为本发明实施例4所述的三维立体型声学超材料挡片消声器和无挡片消声器的传声损失仿真结果对比图。其中，实线对应三维立体型声学超材料挡片消声器结果，虚线对应无挡片消声器结果。据图可知，三维立体型声学超材料挡片消声器的有效消声频率出现在400Hz附近，相比无挡片消声器，传声损失提高约3～5dB。该实施例尤其适合于管径较小的消声管路，三维立体型PAMB可显著提高薄膜的振动面积，确保具有良好的低频消声效果。
图17为本发明实施例5所述的三明治型PAMB的结构示意图。其构成是将两层框架(50)和(51)贴附到穿孔薄膜(52)的左右两侧并夹紧穿孔薄膜(52)。该实施例所述构型可提高PAMB的工作稳定性，使其胜任于高流速、强冲击流等场合。
图18为本发明实施例6所述的倾斜型声学超材料挡片消声器的结构示意图。其中，倾斜型PAMB(54)以一定角度α倾斜放置在消声器外部腔体(53)的内壁面。
其中，消声器外部腔体(53)的结构尺寸及材料构成同实施例1。倾斜型PAMB(54)的安装倾角为α，其轴向横截面投影尺寸同实施例1所示的基本型PAMB(14)。倾斜型PAMB(54)的边框、有孔约束体以及连接杆的材料相同， 均为SPCC冷轧钢；薄膜的厚度为0.05mm，材质为聚醚酰亚胺。
图19为本发明实施例6所述的包含不同倾斜角度PAMB的倾斜型声学超材料挡片消声器的传声损失试验结果对比图。其中，实线对应α＝30°安装的消声器结果，虚线对应α＝45°安装的消声器结果。据图可知，安装倾角α越小，PAMB起作用的消声尖峰越偏向低频，即安装倾角α由45°减小到30°时，消声尖峰由600Hz移动到450Hz，其他频段的传声损失改变不大。该实施例所属构型非常适用于管道口径小且对通流要求高的场合。
图20为本发明实施例7所述的由多个PAMB面内阵列组成的PAMB阵列挡片消声器的结构示意图。该实施例所述构型能够保证PAMB阵列挡片具有足够的弯曲刚度，便于大尺寸截面的中空膨胀腔内部的挡片安装。
图21为本发明实施例8所述的法兰装配、螺纹装配和焊接装配声学超材料挡片消声器的装配结构示意图。其中，图21(a)对应法兰装配方法；图21(b)对应螺纹装配方法；图21(c)对应焊接装配方法。
其中，法兰装配方法是将消声器的两个拼接件(59)和(60)的两个端面法兰(61)和(62)对接，通过螺栓(63)和螺母(64)配合旋紧连接。螺纹装配方法是将消声器的母端拼接件(65)与公端拼接件(66)对接，通过母端拼接件的内螺纹端(67)与公端拼接件的外螺纹端(68)配合旋紧连接。焊接装配方法是将消声器的母端拼接件(69)与公端拼接件(70)对接，通过公端拼接件的焊接区(71)进行焊接连接。
图22为本发明实施例9所述的一种辊压加工声学超材料挡片消声器的工艺流程。第①步，在PAMB(72)边框的整个外轮廓加工环状凹槽，环状凹槽采用铸造、车削等加工方式实现；第②步，通过定位工具(73)夹持PAMB(72)到中空管(74)内部，利用定位工具(73)的刻度尺确定固定位置；第③步，移动辊刀(75)刀头到中空管(74)外壁面对应PAMB(72)的凹槽位置并施加一定压力，与此同时，定位工具(73)夹持PAMB(72)和中空管(74)一起周向旋转，使得中空管(74)向内形成的凸起与内部PAMB(72)边框的凹槽紧扣配合。其中，对于薄壁中空管可以一次进刀旋压加工，对于较厚中空管则需要多次进刀旋压，或者仅在多点进行挤压，无需整个环形均进行紧扣配合，多点挤压方式也适合于非圆形中空管的辊压装配。重复上述步骤，可以将多组PAMB固定在待加工中空管指定位置，得到已辊压多组声学超材料挡片的半成品消声器(76)。第④步，利用收口装置(77)，将已辊压多组声学超材料挡片的半成品消声器(76)的两端管口收缩。第⑤步，清理毛刺并精修倒角，最 终得到辊压多组声学超材料挡片的成品消声器(78)。
实施例
下面对本发明实施例中的仿真方法、试验方法以及材料来源进行说明。
消声器传声损失的有限元仿真计算方法:基于商用有限元软件COMSOL Multiphysics 5.2的声-固耦合频域分析模块建立消声器传声损失的有限元仿真计算模型。该仿真模型包括由消声器外部腔体结构和不同类型挡片结构构成的“固体力学物理场”及消声器内部空气腔构成的“压力声学物理场”，两个物理场区域通过声-固界面连续性条件相互耦合关联。不同类型挡片结构的边界条件定义为固支。在入口管端面设置入射声波为平面声波(20～2000Hz频段，扫频步长为10Hz)，并定义入口管及出口管端面为平面波辐射边界条件，根据入口管及出口管端面的声压幅值计算消声器的传声损失(Sound Transmission Loss，简写为STL)：
STL＝20log10|PI/PT|
式中，PI为入口管声压幅值，PT为出口管透射声压幅值。
消声器压力损失的有限元仿真计算方法:基于商用有限元软件COMSOL Multiphysics 5.2的流固耦合稳态分析模块建立消声器压力损失的有限元仿真计算模型。该仿真模型包括由消声器外部腔体结构和不同类型挡片结构构成的“线弹性材料域”及消声器内部空气腔构成的“流体域”，两个域通过流-固界面连续性条件相互耦合关联。不同类型挡片结构的边界条件定义为固支。在入口管端面设置不同的入口流速，并定义出口管端面为出口边界条件，根据入口管及出口管端面的全压计算消声器的压力损失(Pressure Drop，简写为PD)：
PD＝Pin-Pout
式中，Pin为入口全压，Pout为出口全压。
消声器传热效率的有限元仿真计算方法:基于商用有限元软件COMSOL Multiphysics 5.2的声固耦合、流固耦合及流体传热物理场，将声固耦合及流固耦合物理场计算得到的流速分布作为流体传热物理场的流场输入条件。消声器外部腔体壁面温度设定为恒定值作为热源，消声器内部初始温度值设置为293.15K(室温)，其它壁面均设置为绝热边界。在消声器入口管截面施加特定入口流速及特定频率和幅值的平面声波激励，并将消声器出口管截面设置为无回流边界。采用时间历程求解器，计算消声器出口管截面的平均温度值。
消声器传声损失的声阻抗管试验测试方法：在声阻抗管中采用四传声器单负载法测量消声器的传声损失，消声器通过入口过渡管和出口过渡管分别与入 射声管和透射声管连接，在入射声管一侧放置声源，透射声管末端放置吸声尖劈。通过分别放置在入口过渡管和出口过渡管上的两对传声器对入射声波、反射声波和透射声波进行分解，根据消声器的传递矩阵方程求得消声器的传声损失(Munjal M.L.，Acoustics of ducts and mufflers,Wiley,1987.)。
下述实施例中使用的SPCC冷轧钢、6063牌号铝合金、聚醚酰亚胺膜、玻璃纤维棉等材料均为市售购买得到的。
实施例1基本型声学超材料挡片消声器
下面结合附图2-8阐述基本型声学超材料挡片消声器的结构参数、制备方法、性能计算与测定以及机理分析。
1.结构参数及制备方法
使用SPCC冷轧钢板通过激光切割一体成型如图2所示的基本型PAMB(14)的框架，在其一侧胶粘薄膜并进行穿孔操作，基本型PAMB通过套筒定位于膨胀腔(12)内部，消声器外部腔体通过法兰连接方式组装。其中，膨胀腔(12)长度为250mm，内径为46mm；入口管(11)长度为15mm，内径为10mm；出口管(13)长度为15mm，内径为10mm；消声器壁厚均匀，厚度为3mm；基本型PAMB与膨胀腔入射端口的距离为150mm。消声器外部腔体材料为6063牌号铝合金。基本型PAMB(14)的边框为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为16mm，约束体孔的直径为10mm；穿孔薄膜的厚度为0.05mm，其上通孔的直径亦为10mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。边框、有孔约束体以及双臂连接杆的材料相同，均为SPCC冷轧钢；穿孔薄膜的材质为聚醚酰亚胺。
2.性能计算与测定
如图3所示，有限元模型中消声器外部腔体和基本型PAMB(14)设置为“固体力学物理场”，消声器内部空气腔设置为“压力声学物理场”。基本型PAMB(14)的边界条件定义为固支。在入口管(11)端面设置入射声波为平面声波，并定义入口管(11)及出口管(13)端面为平面波辐射边界条件，避免声波的多次反射影响计算结果。入射声波PI激励PAMB产生反射声波PR和透射声波PT。消声器的传声损失则通过STL＝20log10|PI/PT|计算得到。
采用四传声器单负载法测试基本型声学超材料挡片消声器的传声损失，测试系统示意图如图5所示。声阻抗管主要由入射声管(18)和透射声管(19)组成，在入射声管(18)的端部安置声源(17)，其产生的宽频白噪声激励声 波在到达入口过渡管(21)上的传声器(25)之前已经发展成波前幅值趋于一致的平面声波，声波经过待测消声器(23)后进入出口过渡管(22)，并最终进入透射声管(19)，在透射声管(19)的后端安置足够长的吸音尖劈(20)以尽量减少声波的多次反射对测试结果的影响。位于待测消声器(23)两侧，共有四个传声器固定端子(24)，其内插入传声器(25)(型号4187,Brüel&
Figure PCTCN2016090450-appb-000002
)，两两分列于入口过渡管(21)和出口过渡管(22)之上。通过两对传声器对入射声波、反射声波和透射声波进行分解，根据消声器的传递矩阵方程求得消声器的传声损失。
如图3a所示，建立包括由消声器外部腔体和基本型PAMB(14)构成的“线弹性材料域”及消声器内部空气腔构成的“流体域”组成的流固耦合计算有限元仿真模型。基本型PAMB(14)的边界条件定义为固支。在入口管(11)端面设置入口流速分别为1m/s、2m/s、5m/s、10m/s、15m/s、20m/s、25m/s和30m/s，并定义出口管(13)端面为出口边界条件，根据入口管及出口管端面的全压Pin和Pout计算消声器的压力损失为PD＝Pin-Pout。
在上述消声器压力损失计算模型的基础上，增加“声固耦合”和“流体传热”物理场，将声固耦合及流固耦合物理场计算得到的流速分布作为流体传热物理场的流场输入条件。消声器外部腔体壁面温度设定为303.15K，消声器内部初始温度值设置为293.15K，其它壁面均设置为绝热边界。施加在消声器入口管截面的入口流速为5cm/s，入射平面声波的幅值为1Pa，频率为200Hz，并将消声器出口管截面设置为无回流边界。采用时间历程求解器，计算消声器出口管截面的平均温度值。
3.与现有技术的对比
使用与实施例1所述的基本型声学超材料挡片消声器的方法制备如下三种消声器，同等孔径穿孔挡片消声器、同等总和穿孔面积微穿孔挡片消声器和无挡片消声器，并测定其传声损失及压力损失两项性能指标。
参照图3(a)、图3(b)和图3(c)，四类消声器外部腔体的结构尺寸及材料构成均相同，不同之处在于内部安装的挡片。其中，穿孔挡片(15)为圆环形，外径为46mm，内径为10mm，厚度为0.75mm；材料为SPCC冷轧钢；微穿孔挡片(16)的外径为46mm，厚度为0.75mm，内部中心区域分布25个直径为2mm的微孔，微孔中心距离为7mm；材料同样为SPCC冷轧钢。这三种挡片的面密度均为5.67kg/m3，穿孔率(通孔面积/挡片总面积)均为4.73％。
图4为上述消声器的传声损失有限元仿真计算结果对比图。其中，虚线对 应无挡片消声器结果，点线对应穿孔挡片消声器结果，点划线对应微穿孔挡片消声器结果，实线对应基本型声学超材料挡片消声器结果。本发明实施例1所述的基本型声学超材料挡片消声器针对低频的第一阶传声损失低谷，利用PAMB在该低谷对应频率的声波激励产生的全反射振动模式，高效反射声波，显著提高该频率附近的传声损失量值，其传声损失在50～1300Hz连续的低、中频段内均高于10dB，尤其在460Hz比穿孔挡片消声器高约30dB。
为了验证所建有限元传声损失计算模型的有效性，图6给出了上述消声器的传声损失试验测量结果与有限元仿真计算结果的对比。其中，图6(a)对应无挡片消声器结果；图6(b)对应穿孔挡片消声器结果；图6(c)对应微穿孔挡片消声器结果；图6(d)对应基本型声学超材料挡片消声器结果。据图可知，仿真结果和试验结果的吻合程度良好，表明仿真模型计算正确，能用于分析消声器传声损失特性的微观机理，也表明该仿真模型适合于声学超材料挡片消声器的消声频段设计。
图8为上述消声器不同入口空气流速的压力损失对比结果。其中，圆圈标记对应无挡片消声器结果，方形标记对应穿孔挡片消声器结果，三角标记对应微穿孔挡片消声器结果，星号标记对应基本型声学超材料挡片消声器结果。其中，微穿孔挡片消声器的压力损失在不同入射流速输入条件下，均为四者中最大，基本型声学超材料挡片消声器次之，而无挡片消声器的压力损失最小。通常气流管道系统入口流速多在10m/s以下，此时四种消声器的压力损失差别微小，且均在200Pa以下。
图9给出了本发明实施例1所述的基本型声学超材料挡片消声器与同等孔径穿孔挡片消声器的传热效率对比情况。其中，虚线对应穿孔挡片消声器结果，实线对应基本型声学超材料挡片消声器结果。在同样外部热源温度及同样入口流速条件下，基本型声学超材料挡片消声器的传热效率明显高于同等孔径穿孔挡片消声器，其出口温度在更短的时间内达到稳态值。
4.工作机理分析
图7为上述消声器内部腔室空气质点的速度方向分布。其中，图7(a)对应无挡片消声器结果；图7(b)对应穿孔挡片消声器结果；图7(c)对应微穿孔挡片消声器结果；图7(d)对应基本型声学超材料挡片消声器结果。黑色箭头表示声波入射方向。可以明显看出，基本型声学超材料挡片消声器的挡片前后区域出现明显的声波涡旋，明显区别于其他类型的消声器。具体而言，对于无挡片消声器，其仅在出口端近壁面区域出现明显的声波反射现象，穿孔挡片消声器出现声波 反射的区域提前，微穿孔挡片消声器相比于穿孔挡片消声器，出现声波反射的区域更接近出口端。声学超材料挡片消声器的声波反射区域出现在声学超材料挡片的上游端，整个消声器腔室内以反向传播的声波为主。
实施例2含两组声学超材料挡片的消声器
1.结构参数
如图10所示，本发明实施例2所述的含两组PAMB的消声器是在实施例1所述的基本型声学超材料挡片消声器的基础上，再安装一组PAMB构成。两组PAMB(30)和(31)的结构尺寸及材料构成不完全相同，分别针对不同的消声低谷频段。其中，第1组PAMB(30)的边框为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为18mm，约束体孔的直径为12mm；穿孔薄膜的厚度为0.05mm，其上通孔的直径亦为12mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。第2组PAMB(31)的边框同样为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为16mm，约束体孔的直径为10mm；穿孔薄膜的厚度为0.05mm，其上通孔的直径亦为10mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。两组PAMB的边框、有孔约束体以及双臂连接杆的材料相同，均为SPCC冷轧钢；穿孔薄膜的材质均为聚醚酰亚胺。
作为对比，图11给出了与本发明实施例2所述的含两组PAMB的消声器相对应的含两组同等孔径穿孔挡片消声器的结构剖视图。其内部的两组穿孔挡片(32)和(33)的通孔尺寸分别与两组PAMB(30)和(31)对应。其中，穿孔挡片(32)为圆环形，外径为46mm，内径为12mm，厚度为0.75mm；穿孔挡片(33)同样为圆环形，外径为46mm，内径为10mm，厚度为0.75mm；两组穿孔挡片的材料均为SPCC冷轧钢。第1组挡片(30)和(32)的面密度均为5.49kg/m3，穿孔率均为6.81％；第2组挡片(31)和(33)的面密度均为5.67kg/m3，穿孔率均为4.73％。两类消声器外部腔体的结构及尺寸均相同，膨胀腔长度L＝250mm，内径D＝46mm；入口管长度L1＝15mm，内径d1＝10mm；出口管长度L2＝15mm，内径d2＝10mm；消声器壁厚均匀，厚度h＝3mm；第1组挡片(30)和(32)与膨胀腔入射端口的距离l1＝L/3，第2组挡片(31)和(33)与膨胀腔出射端口的距离l2＝L/3。消声器外部腔体材料为6063牌号铝合金。
2.性能分析
图12为本发明实施例2所述的含两组PAMB的消声器和含两组同等孔径穿孔挡片消声器的传声损失仿真结果对比图。其中，实线对应含两组PAMB的消声器结果，虚线对应含两组穿孔挡片消声器结果。可以明显看出，含两组PAMB的消声器有效弥补了含两组穿孔挡片消声器分别位于400Hz和760Hz的两个驻波消声低谷，从而显著提高了低频有效消声带宽和消声量级。
实施例3吸声材料封闭阻抗复合型消声器
1.结构参数
如图13所示，本发明实施例2所述的由两层PAMB中间填充吸声材料所构成的吸声材料封闭阻抗复合型消声器内部包含一组吸声材料密封阻抗复合型挡片(35)，其由两层PAMB中间夹持吸声材料构成。其中，第1层PAMB(包含框架(37)和穿孔薄膜(36))与第2层PAMB(包含框架(41)和穿孔薄膜(42))通过支架(40)连接，支架(40)外围铺设环形包覆膜(39)，在环形包覆膜(39)与消声器腔体(34)内壁面间填充吸声材料(38)。其中，消声器外部腔体(34)的结构尺寸及材料构成同实施例1。第1层PAMB的边框为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为16mm，约束体孔的直径为10mm；穿孔薄膜的厚度为0.05mm，其通孔的直径亦为10mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。第2层PAMB的边框同样为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体的外径为11mm，约束体孔的直径为5mm；穿孔薄膜的厚度为0.05mm，其通孔的直径亦为5mm；有孔约束体与边框之间的双臂连接杆为矩形截面，宽3mm，厚2mm。两层PAMB的边框、有孔约束体以及双臂连接杆的材料相同，均为SPCC冷轧钢；穿孔薄膜的材质均为聚醚酰亚胺。支架(40)由两根支撑杆组成，其长50mm，宽3mm，厚2mm。环形包覆膜(39)的厚度为0.038mm，材料为聚醚酰亚胺。吸声材料(38)为玻璃纤维棉，容重为9.6kg/m3，流阻率为19000Nsm-4，填充长度为50mm。
2.性能分析
图14为本发明实施例3所述的由两层PAMB中间填充吸声材料所构成的吸声材料封闭阻抗复合型消声器和两层PAMB中间不填充吸声材料的消声器的传声损失试验测试结果对比图。其中，实线对应吸声材料封闭阻抗复合型消声器结果，虚线对应两层PAMB中间不填充吸声材料的消声器结果。相比于两层PAMB中间不填充吸声材料的消声器，吸声材料封闭阻抗复合型消声器在全频 段内无明显消声塌陷，整体消声效果优异。
实施例4三维立体型学超材料挡片消声器
1.结构参数
如图15所示，本发明实施例4所述的三维立体型声学超材料挡片消声器的边框(45)与有孔约束体(46)不在同一平面内，二者相距一定距离并通过倾斜连接杆(47)刚性连接，薄膜(48)成圆台状包覆在边框(45)和约束体(46)的侧面。其中，消声器外部腔体(43)的结构尺寸及材料构成同实施例1。三维立体型PAMB的边框(45)为圆环形，外径为46mm，内径为40mm，厚度为2mm；有孔约束体(46)的外径为16mm，约束体孔的直径为10mm；穿孔薄膜(48)的厚度为0.05mm，其上通孔的直径亦为10mm；有孔约束体与边框之间的双臂倾斜连接杆为矩形截面，宽3mm，厚2mm，轴向垂直高度为20mm。边框(45)、有孔约束体(46)以及倾斜连接杆(47)的材料相同，均为SPCC冷轧钢；薄膜(48)的材质为聚醚酰亚胺。
2.性能分析
图16为本发明实施例4所述的三维立体型声学超材料挡片消声器和无挡片消声器的传声损失仿真结果对比图。其中，实线对应三维立体型声学超材料挡片消声器结果，虚线对应无挡片消声器结果。据图可知，三维立体型声学超材料挡片消声器的有效消声频率出现在400Hz附近，相比无挡片消声器，传声损失提高约3～5dB。该实施例尤其适合于管径较小的消声管路，三维立体型PAMB可显著提高薄膜的振动面积，确保具有良好的低频消声效果。
实施例5三明治型声学超材料挡片
如图17所示，本发明实施例5所述的三明治型PAMB是将两层框架(50)和(51)贴附到穿孔薄膜(52)的左右两侧并夹紧穿孔薄膜(52)构成。该实施例所述构型由于两侧面紧固穿孔薄膜，可提高PAMB的工作稳定性，使其胜任于高流速、强冲击流等场合，如针对气动阀门的开关产生的瞬时脉冲噪声的处理。
实施例6倾斜型声学超材料挡片消声器
1.结构参数
如图18所示，本发明实施例6所述的倾斜型声学超材料挡片消声器内部的 倾斜型PAMB(54)以一定角度α倾斜放置在消声器外部腔体(53)的内壁面。其中，消声器外部腔体(53)的结构尺寸及材料构成同实施例1。倾斜型PAMB(54)的安装倾角为α，其轴向横截面投影尺寸同实施例1所示的基本型PAMB(14)。倾斜型PAMB(54)的边框、有孔约束体以及连接杆的材料相同，均为SPCC冷轧钢；薄膜的厚度为0.05mm，材质为聚醚酰亚胺。
2.性能分析
图19为本发明实施例6所述的包含不同倾斜角度PAMB的倾斜型声学超材料挡片消声器的传声损失试验结果对比图。其中，实线对应α＝30°安装的消声器结果，虚线对应α＝45°安装的消声器结果。据图可知，安装倾角α越小，PAMB起作用的消声尖峰越偏向低频，即安装倾角α由45°减小到30°时，消声尖峰由600Hz移动到450Hz，其他频段的传声损失改变不大。该实施例所属构型非常适用于管道口径小且对通流要求高的场合。
实施例7PAMB阵列挡片消声器
图20为本发明实施例7所述的由多个PAMB面内阵列组成的PAMB阵列挡片消声器的结构示意图。PAMB阵列挡片(56)包括含多个相同或不同结构尺寸的PAMB单元以及与之贴合对应的穿孔薄膜(58)。该实施例所述构型能够保证PAMB阵列挡片具有足够的弯曲刚度，便于大尺寸截面的中空膨胀腔内部的挡片安装。
实施例8三种声学超材料挡片消声器的装配方法
图21为本发明实施例8所述的法兰装配、螺纹装配和焊接装配声学超材料挡片消声器的装配结构示意图。其中，图21(a)对应法兰装配方法；图21(b)对应螺纹装配方法；图21(c)对应焊接装配方法。
其中，法兰装配方法是将消声器的两个拼接件(59)和(60)的两个端面法兰(61)和(62)对接，通过螺栓(63)和螺母(64)配合旋紧连接。螺纹装配方法是将消声器的母端拼接件(65)与公端拼接件(66)对接，通过母端拼接件的内螺纹端(67)与公端拼接件的外螺纹端(68)配合旋紧连接。焊接装配方法是将消声器的母端拼接件(69)与公端拼接件(70)对接，通过公端拼接件的焊接区(71)进行焊接连接。
实施例9一种辊压加工声学超材料挡片消声器的工艺流程
本发明实施例9所述的一种辊压加工声学超材料挡片消声器的工艺流程如图22所示，共分为五步。第①步，在PAMB(72)边框的整个外轮廓加工环状凹槽，环状凹槽采用铸造、车削等加工方式实现；第②步，通过定位工具(73)夹持PAMB(72)到中空管(74)内部，利用定位工具(73)的刻度尺确定固定位置；第③步，移动辊刀(75)刀头到中空管(74)外壁面对应PAMB(72)的凹槽位置并施加一定压力，与此同时，定位工具(73)夹持PAMB(72)和中空管(74)一起周向旋转，使得中空管(74)向内形成的凸起与内部PAMB(72)边框的凹槽紧扣配合。其中，对于薄壁中空管可以一次进刀旋压加工，对于较厚中空管则需要多次进刀旋压，或者仅在多点进行挤压，无需整个环形均进行紧扣配合，多点挤压方式也适合于非圆形中空管的辊压装配。重复上述步骤，可以将多组PAMB固定在待加工中空管指定位置，得到已辊压多组声学超材料挡片的半成品消声器(76)。第④步，利用收口装置(77)，将已辊压多组声学超材料挡片的半成品消声器(76)的两端管口收缩。第⑤步，清理毛刺并精修倒角，最终得到辊压多组声学超材料挡片的成品消声器(78)。
最后，需要注意的是：以上列举的仅是本发明的具体实施例子，当然本领域的技术人员可以对本发明进行改动和变型，倘若这些修改和变型属于本发明权利要求及其等同技术的范围之内，均应认为是本发明的保护范围。

Claims (19)

  1. 一种消声器，其特征在于，其包括入口管、出口管、入口管与出口管之间的中空膨胀腔、以及在所述的中空膨胀腔内至少一个截面上竖向或倾斜设置有含通孔的声学超材料挡片。
  2. 如权利要求1所述的消声器，其特征在于，所述含通孔的声学超材料挡片包含边框，在所述边框内设置至少一个约束体，在边框两侧表面的至少一个表面上覆盖有薄膜，所述约束体和薄膜上均设置有至少一个通孔。
  3. 如权利要求1所述的消声器，其特征在于，所述中空膨胀腔的截面形状根据消声器的安装空间及消声器膨胀比等参数要求确定；优选中空膨胀腔的横截面形状为圆形、椭圆形、长方形、正多边形；优选中空膨胀腔的纵截面形状为矩形、锥形、波状。
  4. 如权利要求2或3所述的消声器，其特征在于，所述边框为中空结构，其外轮廓形状与中空膨胀腔的截面形状一致；约束体设置在边框的内部，约束体和边框通过至少一根连接杆刚性连接；薄膜外周区域贴合边框表面，内部区域受约束体约束；优选所述约束体及连接杆与边框齐平。
  5. 如权利要求2-4任一项所述的消声器，其特征在于，约束体和薄膜的通孔大小根据通流需求以及消声频段两方面共同确定；优选所述约束体和薄膜上的通孔的孔径大于2毫米。
  6. 如权利要求2-5任一项所述的消声器，其特征在于，所述约束体和薄膜上的通孔的形状、位置和大小相同或不同；优选所述通孔的形状、位置和大小相同；优选所述通孔的形状为对称规则形状，进一步优选为圆形、椭圆形、正多边形。
  7. 如权利要求2-6任一项所述的消声器，其特征在于，所述约束体与薄膜的接触区域为线或面；优选接触形状是对称规则的几何形状；更优选所述的几何形状为圆形、椭圆形、正多边形。
  8. 一种改进的抗性消声器，其特征在于，在传统抗性消声器的内部截面上设置至少一个含通孔的声学超材料挡片，优选含通孔的声学超材料挡片的工作频段涵盖所述传统抗性消声器的驻波消声低谷频段；更优选所述含通孔的声学超材料挡片的峰值工作频率与各阶驻波频率一致。
  9. 一种改进的阻性消声器，其特征在于，将吸声材料用一层或多层含通孔的声学超材料挡片封闭，避免吸声材料与通过流体直接接触；优选所述一层含通孔的声学超材料挡片的厚度大于5毫米；优选所述一层含通孔的声学超材料挡片的边框两侧表面均覆盖有薄膜，两层薄膜内部填充与薄膜阻抗相匹配的多孔材料；优选所述多层含通孔的声学超材料挡片通过支架定位，将一层不透薄膜包覆在支架外围，在不透薄膜与膨胀腔壁面之间的空腔内或者在两层薄膜中间填充与薄膜阻抗相匹配的多孔材料；优选不透薄膜的材料与含通孔的声学超材料挡片的薄膜一样；优选所述多孔材料为玻璃纤维棉或开、闭孔泡沫。
  10. 如权利要求1-7任一项所述消声器，其特征在于，其用于增强流体传热效率。
  11. 一种包含所述含通孔的声学超材料挡片的阵列挡片，其由多个含通孔的声学超材料挡片在面内方向阵列组合拼接而成；当需要宽频消声时，优选形成阵列挡片的各个含通孔的声学超材料挡片的几何尺寸和材料参数不同，当需要窄带消声时，优选形成阵列挡片的各个含通孔的声学超材料挡片的几何尺寸和材料参数相同。
  12. 如权利要求2-10任一项所述消声器及权利要求11所述的阵列挡片，所述含通孔的声学超材料挡片的边框和约束体的材料为金属材料或非金属材料，优选金属材料为铝、铁、钢、铜，优选非金属材料为木材、陶瓷、橡胶、玻璃、石膏、水泥、高分子聚合物或复合纤维材料；所述薄膜的材料为高分子聚合物薄膜材料、金属薄膜材料或弹性薄膜材料，所述聚合物薄膜材料优选为聚醚酰亚胺膜、聚氯乙烯膜、聚乙烯膜、所述金属薄膜材料优选铝及铝合金膜、钛及钛合金膜，所述弹性薄膜材料优选为橡胶膜、硅胶膜、乳胶膜。
  13. 一种消除传统抗性消声器的驻波消声低谷的方法，所述方法包括如下步骤：将含通孔的声学超材料挡片安装在传统抗性消声器的内部横截面上，并且使含通孔的声学超材料挡片的工作频段涵盖所述传统抗性消声器的驻波消声低谷频段；优选所述含通孔的声学超材料挡片的工作频段与低频的第一阶驻波频率一致。
  14. 一种调节权利要求2-10任一项所述消声器消声频段的方法，在消声器膨胀腔形状及尺寸不变的前提下，通过改变所述含通孔的声学超材料挡片的边框、 约束体及薄膜的结构尺寸和材料参数来实现调节含通孔的声学超材料挡片的有效工作频段，提高消声器在该频段内的消声性能。
  15. 一种装配所述含通孔的声学超材料挡片的方法，其特征在于，所述有孔约束体和边框采用一体成型技术制备得到，或者制造有孔约束体预制件和边框预制件，将有孔约束体预制件通过连接杆刚性连接到边框预制件上组成框架，之后将薄膜覆盖在框架上，并进行固定连接，最后在薄膜上进行打孔；或者采用两层所述的框架将薄膜夹持在中间，并进行固定连接；优选通过铣削、铸造、冲压、激光切割或3D打印技术加工为一体成型的框架，或者通过铣削、铸造、冲压、激光切割或3D打印技术制造出有孔约束体预制件和边框预制件；优选固定连接为胶粘、热焊接或机械铆接。
  16. 一种装配权利要求2-10任一项所述消声器的方法，其特征在于，通过定位工具将含通孔的声学超材料挡片送至中空管内部既定位置，移动辊刀刀头到中空管外壁面对应位置并施加一定压力，将含通孔的声学超材料挡片嵌于中空管中；对中空管进行两端收口成形，优选收口成形采用模具成型、旋压成型、出入口管焊接成形。
  17. 一种装配权利要求2-10任一项所述消声器的方法，其特征在于，通过冲压或热装配的方法将含通孔的声学超材料挡片装入中空管内，利用过盈配合的约束力将含通孔的声学超材料挡片固定于中空管的既定位置；对中空管进行两端收口成形，优选收口成形采用模具成型、旋压成型、出入口管焊接成形。
  18. 一种装配权利要求2-10任一项所述消声器的方法，其特征在于，通过定位夹具将含通孔的声学超材料挡片装入中空管内的既定位置，再利用超声波、激光、氩弧焊等工艺点焊固定含通孔的声学超材料挡片，或者采用套筒、弹簧等结构定位含通孔的声学超材料挡片；对中空管进行两端收口成形，优选收口成形采用模具成型、旋压成型、出入口管焊接成形。
  19. 一种装配权利要求2-10任一项所述消声器的方法，其特征在于，通过铸造、车削、冲压工艺制造出两个或多个消声器拼接件，优选消声器拼接件是轴切对半式，在其中一半消声器拼接件既定位置安装固定含通孔的声学超材料挡片后，扣合另一半消声器拼接件并合缝；优选安装固定含通孔的声学超材料挡片的方法包括焊接、凹槽紧箍、套筒定位，优选合缝方式为焊接、铆接、铰接、胶粘。
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CN112951190A (zh) * 2021-02-19 2021-06-11 哈尔滨工程大学 一种基于声学超材料的变截面管路低频宽带减振装置
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CN113793586A (zh) * 2021-08-24 2021-12-14 武汉理工大学 低频超宽带声学黑洞声学材料结构
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