Integrated silencer volute and method for suppressing aerodynamic noise

Abstract

The application provides a silencer integrated volute, the integrated volute (1) comprises a silencer (2), the silencer (2) comprises a silencing device (3) and a control device (4); the silencing device (3) comprises a perforated plate (31), a resonance cavity (32) and an outer wall plate (33) arranged from inside to outside; the perforated plate (31) is provided with a perforated structure; the perforated plate (31) and the outer wall plate (33) are provided with the resonance cavity (32) therebetween; the control device (4) comprises a motor (41) and a partition plate (42); the application can switch the resonance frequency of the Helmholtz resonance cavity by adjusting the rotation angle of the partition plate according to the running rotating speed of the air compressor, so that the energy of the significant rotating base frequency of the aerodynamic noise can be greatly attenuated, and the targeted noise suppression effect under different rotating speeds of the air compressor can be realized.

Description

Technical Field

[0001] This invention relates to the field of air compressor noise suppression technology, and in particular to an integrated muffler housing and a method for suppressing aerodynamic noise. Background Technology

[0002] Air compressors exhibit flow separation during impeller acceleration, leading to uneven pressure distribution within the diffuser and volute, which induces aerodynamic noise. This noise primarily radiates outwards along the volute outlet direction, with the sound pressure level at the fundamental rotational frequency being particularly significant. Depending on the operating conditions and rotational speed of the air compressor, the corresponding fundamental rotational frequency will vary.

[0003] Perforated tube silencers are based on the Helmholtz principle. They utilize the perforations in the perforated tube and the resonant cavity behind it to form a Helmholtz resonant cavity. When the frequency of aerodynamic noise approaches the natural frequency of the resonant cavity, the cavity absorbs sound energy, reducing aerodynamic noise. Perforated tube silencers have small and numerous perforations, resulting in strong sound energy attenuation and significant noise reduction.

[0004] Perforated tube silencers mainly consist of a perforated tube and a cavity behind it. The perforation diameter, perforation ratio, and volume of the cavity behind the perforated tube significantly affect the noise reduction effect and frequency bandwidth of the silencer. Due to space constraints, altering the volume of the cavity behind the perforated tube is not feasible. Therefore, optimizing the perforation diameter and perforation ratio using the acoustic finite element method is of great significance for the design of perforated tube silencers.

[0005] Existing noise reduction volutes (1) have a sound-absorbing structure at the volute tongue, resulting in a small noise reduction space. For example, the patent titled "Volute, Fan and Air Conditioning Equipment" has disclosed related technical solutions. However, the above technical solutions still have the following defects: 1) The patent only sets up a part of the noise reduction area at the volute tongue, resulting in poor noise consumption effect; 2) The external noise reduction structure occupies space; 3) The perforation diameter and perforation rate are uniform, and there is no targeted noise reduction for the operating speed.

[0006] Therefore, existing technologies need to address the problem of high aerodynamic noise at the volute outlet. Summary of the Invention

[0007] This invention proposes an integrated muffler housing and a method for suppressing aerodynamic noise. It can switch the resonant frequency of the Helmholtz resonant cavity by adjusting the rotation angle of the baffle according to the operating speed of the air compressor, so that the aerodynamic noise energy at the significant rotational fundamental frequency is greatly attenuated, and the targeted noise suppression effect is achieved at different speeds of the air compressor.

[0008] The present invention adopts the following technical solution.

[0009] An integrated volute housing for a muffler, the integrated volute housing (1) including a muffler (2), the muffler (2) including a silencing device (3) and a control device (4); the silencing device (3) includes a perforated plate (31), a resonant cavity (32), and an outer wall plate (33) arranged from the inside out, the perforated plate (31) having a perforated structure, and a resonant cavity (32) being arranged between the perforated plate (31) and the outer wall plate (33). The control device (4) includes a motor (41) and a partition (42).

[0010] The silencing device (3) is integrated into the outlet end of the volute (1).

[0011] The perforated plate surface is provided with a first perforation structure (311) and a second perforation structure (312), wherein the perforation diameter of the first perforation structure is D1 and the perforation rate is A1; and the perforation diameter of the second perforation structure is D2 and the perforation rate is A2.

[0012] The perforated structures (311) and (312) are alternately distributed at 60-degree intervals along the circumferential direction of the inner wall of the perforated plate.

[0013] The resonant cavity (32) is located between the perforated plate (31) and the outer wall plate (33); the distance from the perforated plate (31) to the outer wall plate (33) is H1, and the outer radius of the outer wall plate (33) is R1, wherein: 0.1R1≤H1≤0.2R1.

[0014] The outer radius R1 of the outer wall plate (33) is consistent with the outer radius R2 of the outlet of the volute (1).

[0015] The motor (41) is located outside the outer wall panel (33). The output shaft of the motor (41) meshes with the guide rail (421) on the partition (42) through a gear. The angle of the partition (42) is switched by the motor (41).

[0016] The main body of the partition is a hollow cylinder (422), whose outer radius R4 is the same as the inner radius R3 of the perforated plate (31). The wall thickness of the hollow cylinder (422) is H2. The inner wall of the partition (42) has a groove of 60° in the circumferential direction every 120° along the circumferential direction. The outer wall of the partition (42) extends radially along the end face to form a cylinder (422) with a length of H1 and a radius of R6. The guide rail (421) is fixed on the cylinder (422). The guide rail (421) is a 120° arc. The inner radius R5 of the guide rail (421) is the same as the radius R1 of the outer wall plate (33).

[0017] A noise suppression method for an integrated muffler housing, wherein the integrated muffler housing is used in an air compressor, the housing is an air compressor housing, the motor (41) receives a signal from the air compressor controller, and changes the rotation angle of the partition (42) according to the air compressor speed, thereby switching the perforation diameter and perforation rate of the muffler (2) to achieve targeted noise suppression at different speeds, attenuating the noise energy at the significant rotational fundamental frequency of the air compressor, and effectively suppressing the transmission of air compressor noise.

[0018] When the motor changes the rotation angle of the partition according to the speed of the air compressor, specifically, the motor drives the partition to rotate. When the air compressor is at its rated speed, the partition switches to the first perforated structure (311) that matches the rated speed. When the air compressor is at its full load speed, it switches to the first perforated structure (312) that matches the full load speed. This causes the significant rotating fundamental frequency aerodynamic noise generated by the airflow through the outlet of the volute (1) to resonate with the Helmholtz resonant cavity (32) of the silencer. The aperture wall surface generates damping and friction on the sound wave, attenuating the sound energy of the sound wave, reducing the energy of the sound wave, suppressing the transmission of aerodynamic noise, and achieving the noise reduction effect.

[0019] Air compressors have relatively low aerodynamic noise at lower speeds, such as idling, but higher aerodynamic noise at higher speeds, such as rated operating conditions and full-load operating conditions. In the solution of this invention, the perforation diameter and perforation rate of the perforated structure are set to correspond to the rotational fundamental frequency of the air compressor under rated operating conditions and full-load operating conditions, so that aerodynamic noise can be better suppressed under both common operating conditions.

[0020] The present invention also has the following beneficial technical effects:

[0021] The structure of this invention integrates the silencer (2) at the outlet of the volute (1), which does not occupy space and makes the air compressor volute (1) neat and beautiful as a whole.

[0022] In this invention, when compressed gas flows through the silencing device (3), the frequency of the generated aerodynamic noise is close to the natural frequency of the resonant cavity (32). The resonant cavity (32) absorbs sound energy, which can effectively reduce aerodynamic noise.

[0023] This invention proposes a noise suppression method that adjusts the rotation angle of the baffle (42) according to the operating speed of the air compressor and switches the resonance frequency of the Helmholtz resonant cavity (32), so that the aerodynamic noise energy at the significant rotational fundamental frequency is greatly attenuated, thereby achieving targeted noise suppression at different speeds. Attached Figure Description

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0025] Appendix Figure 1 A perspective view of one embodiment of the volute (1) of the present invention;

[0026] Appendix Figure 2 This is a perspective view of one embodiment of the muffler (2) of the present invention;

[0027] Appendix Figure 3 This is a perspective view of one embodiment of the perforated plate (31) of the present invention;

[0028] Appendix Figure 4 This is a perspective view of one embodiment of the partition (42) of the present invention;

[0029] Appendix Figure 5 For acoustic finite element analysis of the transmission loss of perforated pipe silencers (2) with different perforation diameters;

[0030] Appendix Figure 6 To analyze the transmission loss of perforated pipe silencers (2) with different perforation rates using acoustic finite element method;

[0031] In the figure: 1-volute, 2-silencer, 3-silencing device, 31-perforated plate, 311-first perforated structure, 312-second perforated structure, 32-resonance cavity, 33-outer wall plate, 34-track groove, 41-motor, 42-partition plate, 421-guide rail, 422-cylinder;

[0032] 100-slot. Detailed Implementation

[0033] As shown in the figure, an integrated volute housing for a muffler is disclosed. The integrated volute housing 1 includes a muffler 2, which includes a silencing device 3 and a control device 4. The silencing device 3 includes a perforated plate 31, a resonant cavity 32, and an outer wall plate 33 arranged from the inside out. The perforated plate 31 has a perforated structure, and the resonant cavity 32 is disposed between the perforated plate 31 and the outer wall plate 33. The control device 4 includes a motor 41 and a partition 42.

[0034] The silencing device 3 is integrated into the outlet end of the volute 1.

[0035] The perforated plate surface is provided with a first perforation structure 311 and a second perforation structure 312. The perforation diameter of the first perforation structure is D1 and the perforation rate is A1; the perforation diameter of the second perforation structure is D2 and the perforation rate is A2.

[0036] The perforated structures 311 and 312 are alternately distributed at 60-degree intervals along the circumferential direction of the inner wall of the perforated plate.

[0037] The resonant cavity 32 is located between the perforated plate 31 and the outer wall plate 33; the distance from the perforated plate 31 to the outer wall plate 33 is H1, and the outer radius of the outer wall plate 33 is R1, wherein: 0.1R1≤H1≤0.2R1.

[0038] The outer radius R1 of the outer wall plate 33 is consistent with the outer radius R2 of the outlet of the volute 1.

[0039] The motor 41 is located on the outside of the outer wall panel 33. The output shaft of the motor 41 meshes with the guide rail 421 on the partition 42 through gears. The angle of the partition 42 is switched by the motor 41.

[0040] In this example, the guide rail 421 on the partition 42 is placed in the track groove 34.

[0041] The partition body is a hollow cylinder 422 with an outer radius R4 that is the same as the inner radius R3 of the perforated plate 31. The wall thickness of the hollow cylinder 422 is H2. The inner wall of the partition 42 has grooves 100 at 60° intervals along the circumference every 120°. The outer wall of the partition 42 extends radially along the end face to form a cylinder 422 with a length H1 and a radius R6. The guide rail 421 is fixed on the cylinder 422 and is a 120° arc. The inner radius R5 of the guide rail 421 is the same as the radius R1 of the outer wall plate 33.

[0042] A noise suppression method for an integrated muffler housing, wherein the integrated muffler housing is used in an air compressor, the housing is the air compressor housing, the motor 41 receives a signal from the air compressor controller, and changes the rotation angle of the baffle 42 according to the air compressor speed, thereby switching the perforation diameter and perforation rate of the muffler 2 to achieve targeted noise suppression at different speeds, attenuating the noise energy at the significant rotational fundamental frequency of the air compressor, and effectively suppressing the transmission of air compressor noise.

[0043] When the motor changes the rotation angle of the baffle according to the speed of the air compressor, specifically, the motor drives the baffle to rotate. When the air compressor is operating at its rated speed, the baffle switches to the first perforated structure 311 that matches the rated speed. When the air compressor is at full load speed, it switches to the first perforated structure 312 that matches the full load speed. This causes the significant rotating fundamental frequency aerodynamic noise generated by the airflow through the outlet of the volute 1 to resonate with the Helmholtz resonant cavity 32 of the silencer. The aperture wall surface generates damping and friction on the sound wave, attenuating the sound energy of the sound wave, reducing the energy of the sound wave, suppressing the transmission of aerodynamic noise, and achieving the noise reduction effect.

[0044] Example 1:

[0045] In this example, the transmission loss of the muffler due to the perforated tube diameter and perforation ratio was studied using acoustic finite element method simulation. The conclusions are: when the perforated tube diameter D is in the range of 0.5mm-2mm, the transmission loss of the perforated tube muffler 2 is at least 20dB in the 600-1500Hz range; when the perforation ratio A is in the range of 1%-4%, the transmission loss of the perforated tube muffler 2 is at least 20dB in the 750-2000Hz range. As the perforated tube diameter increases, the resonance peak of the perforated tube muffler 2 shifts to lower frequencies, and the sound absorption effect of the resonance peak first increases and then decreases. With the increase of the perforated tube diameter, the damping and frictional effect of the pore wall on the sound wave increases, attenuating the sound energy of the sound wave, reducing the sound wave energy, and improving the sound absorption performance of the muffler 2; as the perforated tube diameter continues to increase, the attenuated sound wave energy decreases, and the noise reduction effect decreases accordingly. Therefore, appropriately increasing the perforated tube aperture can lower the resonant peak frequency of the perforated tube silencer 2 and improve its sound absorption performance. As the perforation rate increases, the resonant peak of the perforated tube silencer 2 shifts to higher frequencies, and its sound absorption effect gradually increases. Furthermore, as the perforation rate of the perforated tube silencer 2 increases, the resonant peak frequency shifts to higher frequencies, and the sound absorption performance of the resonant peak improves.

[0046] Example 2:

[0047] This example proposes an integrated muffler 2 and volute housing 1, along with a noise suppression method. The volute housing 1 includes a muffler 2, which in turn includes a silencing device 3 and a control device 4. The silencing device 3 includes a perforated plate 31, a resonant cavity 32, an outer wall plate 33, and a track groove 34. The control device 4 includes a motor 41 and a partition 42. The noise suppression method involves the motor 41 receiving a signal from the air compressor controller and adjusting the rotation angle of the partition 42 according to the speed. This allows for switching the perforation diameter and perforation rate of the muffler 2, achieving targeted noise suppression at different speeds. This attenuates the noise energy at the significant rotational fundamental frequency of the air compressor, effectively suppressing the transmission of air compressor noise.

[0048] Air compressors produce relatively low aerodynamic noise at lower speeds, such as idling, but significantly higher noise levels at higher speeds, such as rated and full-load conditions. Therefore, the perforation diameter and perforation rate of the perforated structure must be set to correspond to the fundamental frequency of the air compressor's rotation under both rated and full-load operating conditions. This ensures effective suppression of aerodynamic noise under both common operating conditions.

[0049] The motor 41 receives a signal from the air compressor controller and changes the rotation angle of the baffle 42 according to the speed. At the rated speed, it switches to the perforated structure 311 that matches the rated speed, and at the full-load speed, it switches to the perforated structure 312 that matches the full-load speed. This causes the significant rotating fundamental frequency aerodynamic noise generated by the airflow through the outlet of the volute 1 to resonate with the Helmholtz resonant cavity 32. The aperture wall surface generates damping and friction on the sound wave, attenuating the sound energy of the sound wave, reducing the energy of the sound wave, and suppressing the transmission of aerodynamic noise.

[0050] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0051] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. An integrated silencer volute, characterized by: The integrated volute (1) comprises a muffler (2), the muffler (2) comprises a muffling device (3) and a control device (4); the muffling device (3) comprises a perforated plate (31), a resonance cavity (32) and an outer wall plate (33) arranged from inside to outside, the perforated plate (31) is provided with a perforated structure, and the resonance cavity (32) is arranged between the perforated plate (31) and the outer wall plate (33); The control device (4) comprises a motor (41) and a partition plate (42); The muffling device (3) is integrated at the outlet end of the integrated volute (1); The plate surface of the perforated plate is provided with a first perforated structure (311) and a second perforated structure (312), the first perforated structure has a perforated aperture D1 and a perforation rate A1, and the second perforated structure has a perforated aperture D2 and a perforation rate A2; The motor (41) is arranged outside the outer wall plate (33), the output shaft of the motor (41) is engaged with a guide rail (421) on the partition plate (42) through a gear, and the angle of the partition plate (42) is switched through driving of the motor (41); The main body of the partition plate is a hollow cylinder (422), the outer radius R4 of the hollow cylinder (422) is consistent with the inner radius R3 of the perforated plate (31), the wall thickness of the hollow cylinder (422) is H2, a groove with a circumferential direction of 60° is formed in the inner wall of the partition plate (42) every 120° in the circumferential direction, the outer wall of the partition plate (42) extends out a cylinder (422) with a length of H1 and a radius of R6 in the radial direction of the end surface, the guide rail (421) is fixed on the cylinder (422), the guide rail (421) is a 120° arc, and the inner radius R5 of the guide rail (421) is consistent with the radius R1 of the outer wall plate (33).

2. The integrated muffler and volute of claim 1, wherein: The first perforated structure (311) and the second perforated structure (312) are alternately distributed every 60 degrees in the circumferential direction of the inner wall of the perforated plate.

3. The integrated muffler and volute of claim 1, wherein: The resonance cavity (32) is located between the perforated plate (31) and the outer wall plate (33); the distance from the perforated plate (31) to the outer wall plate (33) is H1, and the outer radius of the outer wall plate (33) is R1, wherein 0.1R1≤H1≤0.2R1.

4. The integrated muffler and volute of claim 1, wherein: The outer radius R1 of the outer wall plate (33) is consistent with the outer radius R2 of the outlet of the integrated volute (1).

5. A method of suppressing aerodynamic noise of a muffler integrated scroll, for the muffler integrated scroll according to claim 2, characterized by: In the method, the integrated volute muffler is used for an air compressor, the volute is an air compressor volute, the motor (41) receives an air compressor controller signal, changes the rotation angle of the partition plate (42) according to the rotation speed of the air compressor, and then switches the perforated aperture and the perforation rate of the muffler (2), so that the noise at the significant rotation frequency of the air compressor is attenuated, and the noise transmission of the air compressor is effectively suppressed.

6. The method of claim 5, wherein: When the motor changes the rotation angle of the partition plate according to the rotation speed of the air compressor, specifically, the motor drives the rotation of the partition plate, when the working condition of the air compressor is at the rated rotation speed, the partition plate is switched to the first perforated structure (311) matched with the rated rotation speed, and when the air compressor is at the full load rotation speed, the partition plate is switched to the second perforated structure (312) matched with the full load rotation speed, so that the significant rotating fundamental frequency aerodynamic noise generated by the airflow flowing out of the volute (1) resonates with the resonance cavity (32) of the muffler: the hole diameter wall surface produces damping and friction effect on the sound wave, attenuates the sound energy of the sound wave, reduces the energy of the sound wave, suppresses the transmission of the aerodynamic noise, and achieves the muffling effect.

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