Silencer integrated volute and aerodynamic noise suppression method

Abstract

The invention provides a silencer integrated volute which is characterized in that the integrated volute (1) comprises a silencer (2), and the silencer (2) comprises a silencing device (3) and a control device (4); the silencing device (3) comprises a perforated plate (31), a resonant cavity (32) and an outer wall plate (33) which are arranged from inside to outside, the perforated plate (31) is provided with a perforated structure, and the resonant 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 resonant frequency of the Helmholtz resonant cavity can be switched by adjusting the rotating angle of the partition plate according to the running rotating speed of the air compressor, so that aerodynamic noise energy at the remarkable rotating fundamental frequency is greatly attenuated, and the targeted noise suppression effect of the air compressor at different rotating speeds is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of air compressor noise suppression, in particular to a muffler integrated volute and a pneumatic noise suppression method. Background Art

[0002] The air compressor has flow separation phenomenon during the impeller speed increase process, which leads to uneven pressure distribution in the diffuser and volute, inducing aerodynamic noise, and radiating outward mainly along the volute outlet direction. The noise sound pressure level at the rotational fundamental frequency is particularly significant. The air compressor operating conditions are different, the speed is different, and the rotational fundamental frequency corresponding to the speed is different.

[0003] The perforated tube silencer is based on the Helmholtz principle. It uses the perforations on the perforated tube and the resonance cavity behind the perforated tube to form a Helmholtz resonance cavity. When the frequency of the aerodynamic noise is close to the natural frequency of the resonance cavity, the resonance cavity can absorb the sound energy and reduce the aerodynamic noise. The perforations of the perforated tube silencer are small in diameter and large in number. It has a strong ability to attenuate sound energy and a significant noise reduction effect.

[0004] The perforated tube silencer is mainly composed of a perforated tube and the cavity behind it. The perforated tube aperture, perforation rate, and cavity volume behind the perforated tube have a great influence on the noise reduction effect and noise reduction frequency bandwidth of the perforated tube silencer. Due to space limitations, the feasibility of changing the cavity volume behind the perforated tube is poor. Optimizing the perforated tube aperture and perforation rate through the acoustic finite element method is of great significance to the design of the perforated tube silencer.

[0005] The existing noise reduction volute (1) has a silencer structure at the volute tongue, and the noise reduction space is small. For example, the patent with patent announcement number: 106122098 A and patent name: volute, fan and air conditioning equipment has disclosed relevant technical solutions, but the above technical solutions still have the following defects: 1) The patent only sets a partial noise reduction area at the volute tongue, and the noise consumption effect is poor; 2) The external noise reduction structure occupies space; 3) The perforation aperture and perforation rate are single, and no targeted noise reduction is performed on the operating speed.

[0006] Therefore, the existing technology needs to solve the problem of high aerodynamic noise at the volute outlet. Summary of the invention

[0007] The present invention proposes a muffler integrated volute and a pneumatic noise suppression method, which can switch the resonant frequency of the Helmholtz resonance cavity by adjusting the rotation angle of the partition according to the operating speed of the air compressor, so that the pneumatic noise energy at the significant rotational fundamental frequency is greatly attenuated, thereby achieving targeted noise suppression effects at different speeds of the air compressor.

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

[0009] A muffler integrated volute, the integrated volute (1) comprising a muffler (2), the muffler (2) comprising a muffler device (3) and a control device (4); the muffler device (3) comprising a perforated plate (31), a resonance cavity (32), and an outer wall plate (33) arranged from the inside to the outside, the perforated plate (31) being provided with a perforated structure, and a resonance cavity (32) being provided between the perforated plate (31) and the outer wall plate (33). The control device (4) comprises a motor (41) and a partition plate (42).

[0010] The silencer (3) is integrated at the outlet end of the volute (1).

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

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

[0013] The resonance cavity (32) is located between the perforated plate (31) and the outer wall plate (33); the distance between the perforated plate (31) and 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 placed outside the outer wall plate (33); the output shaft of the motor (41) is meshed with a guide rail (421) on the partition plate (42) via a gear, and the angle of the partition plate (42) is switched by driving the motor (41).

[0016] The partition body is a hollow cylinder (422), whose outer radius R4 is consistent with 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) is provided with grooves of 60° in the circumferential direction at intervals of 120° along the circumferential direction; the outer wall of the partition (42) radially extends along the end face to form a cylinder (422) of length H1 and radius 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 consistent with the radius R1 of the outer wall plate (33).

[0017] A noise suppression method for a muffler integrated volute, wherein the muffler integrated volute is used for an air compressor, the volute is an air compressor volute, a motor (41) receives a signal from an air compressor controller, changes the rotation angle of a partition (42) according to the air compressor speed, and then switches the perforation aperture and perforation rate of the muffler (2), thereby achieving targeted noise suppression at different speeds, attenuating the noise energy at a 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 the rated speed, the partition is switched to the first perforated structure (311) matching the rated speed. When the air compressor is at full load speed, the partition is switched to the first perforated structure (312) matching the full load speed, so that the significant rotational fundamental frequency aerodynamic noise generated by the airflow flowing through the outlet of the volute (1) resonates with the Helmholtz resonance cavity (32) of the muffler: the aperture wall produces damping and friction effects 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 muffler effect.

[0019] The air compressor has a relatively small aerodynamic noise at a relatively low speed, such as at idle speed, and a relatively large aerodynamic noise at a relatively high speed, such as at rated operating conditions and at full load conditions. In the scheme of the present invention, the perforation aperture and perforation rate of the perforated structure need to be set to correspond to the rotational fundamental frequency of the air compressor at rated operating conditions and at full load conditions, so that the aerodynamic noise under the two common operating conditions can be better suppressed.

[0020] The present invention also has the following beneficial technical effects: The structure of the present invention integrates the muffler (2) at the outlet of the volute (1), does not occupy space, and makes the volute (1) of the air compressor neat and beautiful as a whole.

[0021] In the present invention, when compressed gas flows through the silencer (3), the frequency of the generated aerodynamic noise is close to the natural frequency of the resonance cavity (32), and the resonance cavity (32) absorbs the sound energy, thereby effectively reducing the aerodynamic noise.

[0022] The present invention provides a noise suppression method, which adjusts the rotation angle of a partition (42) according to the operating speed of an air compressor, switches the resonance frequency of a Helmholtz resonance cavity (32), and significantly attenuates the energy of aerodynamic noise at a significant rotational fundamental frequency, thereby achieving targeted noise suppression at different rotation speeds. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments: Attached Figure 1 A three-dimensional diagram of an embodiment of the volute (1) of the present invention; Attached Figure 2 A stereoscopic diagram of an embodiment of a muffler (2) of the present invention; Attached Figure 3 A three-dimensional diagram of an embodiment of a perforated plate (31) of the present invention; Attached Figure 4 A three-dimensional diagram of an embodiment of a partition (42) of the present invention; Attached Figure 5 To analyze the transmission loss of the perforated pipe muffler (2) with different perforation diameters by acoustic finite element method; Attached Figure 6 To analyze the transmission loss of the perforated pipe muffler (2) with different perforation ratios by acoustic finite element method; In the figure: 1-volute, 2-muffler, 3-muffler, 31-perforated plate, 311-first perforated structure, 312-second perforated structure, 32-resonance chamber, 33-outer wall plate, 34-track groove, 41-motor, 42-partition plate, 421-guide rail, 422-cylinder; 100-slots. DETAILED DESCRIPTION

[0024] As shown in the figure, a muffler integrated volute, the integrated volute 1 includes a muffler 2, the muffler 2 includes a muffler device 3 and a control device 4; the muffler device 3 includes a perforated plate 31, a resonance cavity 32, and an outer wall plate 33 arranged from the inside to the outside, the perforated plate 31 is provided with a perforated structure, and a resonance cavity 32 is provided between the perforated plate 31 and the outer wall plate 33. The control device 4 includes a motor 41 and a partition plate 42.

[0025] The muffler 3 is integrated at the outlet end of the volute 1 .

[0026] The perforated plate surface 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 ; the second perforated structure has a perforated aperture D2 and a perforation rate A2 .

[0027] The perforated structures 311 and 312 are alternately distributed every 60 degrees along the circumferential direction of the inner wall of the perforated plate.

[0028] 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.

[0029] The outer radius R1 of the outer wall plate 33 is consistent with the outer radius R2 of the outlet of the volute 1 .

[0030] The motor 41 is placed outside the outer wall plate 33 , and the output shaft of the motor 41 is meshed with the guide rail 421 on the partition 42 through a gear, and the angle of the partition 42 is switched by driving the motor 41 .

[0031] In this example, the guide rail 421 on the partition plate 42 is placed in the track groove 34 .

[0032] The partition body is a hollow cylinder 422, whose outer radius R4 is consistent with the inner radius R3 of the perforated plate 31, and the wall thickness of the hollow cylinder 422 is H2. The inner wall of the partition 42 has grooves 100 with a circumferential angle of 60° every 120° along the circumferential direction. The outer wall of the partition 42 radially extends a cylinder 422 with a length of H1 and a radius of R6 along the end face. 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.

[0033] A noise suppression method for a muffler integrated volute, in which the muffler integrated volute is used for an air compressor, the volute is an air compressor volute, the motor 41 receives a signal from an air compressor controller, changes the rotation angle of the partition 42 according to the air compressor speed, and then switches the perforation aperture and perforation rate of the muffler 2, to achieve targeted noise suppression at different speeds, attenuate the noise energy at the significant rotational fundamental frequency of the air compressor, and effectively suppress the transmission of air compressor noise.

[0034] 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 the rated speed, the partition is switched to the first perforated structure 311 that matches the rated speed, and when the air compressor is at full load speed, it is switched to the first perforated structure 312 that matches the full load speed, so that the significant rotational fundamental frequency aerodynamic noise generated by the airflow flowing through the outlet of the volute 1 resonates with the Helmholtz resonance cavity 32 of the muffler: the aperture wall produces damping and friction effects on the sound wave, attenuates the sound energy of the sound wave, reduces the energy of the sound wave, suppresses the transmission of aerodynamic noise, and achieves the muffler effect.

[0035] Embodiment 1: In this example, the transmission loss of the perforated tube aperture and perforation rate of the muffler is simulated by the acoustic finite element method, and the conclusion is: when the perforation aperture D ranges from 0.5mm to 2mm, the transmission loss of the perforated tube muffler 2 is at least 20dB at 600-1500Hz; when the perforation rate A ranges from 1% to 4%, the transmission loss of the perforated tube muffler 2 is at least 20dB at 750-2000Hz. As the perforated tube aperture increases, the resonance peak of the perforated tube muffler 2 shifts to low frequency, and the sound absorption effect of the resonance peak increases first and then decreases. As the perforated tube aperture increases, the damping and friction effects of the aperture wall on the sound wave are enhanced, the sound energy of the sound wave is attenuated, the energy of the sound wave is reduced, and the sound absorption performance of the muffler 2 is improved; when the perforation aperture continues to increase, the attenuated sound wave energy decreases, and the noise reduction effect decreases accordingly. Therefore, appropriately increasing the aperture of the perforated tube can reduce the resonance peak frequency of the perforated tube muffler 2 and improve the sound absorption performance of the perforated tube muffler 2. As the perforation rate increases, the resonance peak of the perforated tube muffler 2 shifts to high frequency, and the sound absorption effect of the perforated tube muffler 2 gradually increases. As the perforation rate of the perforated tube muffler 2 increases, the resonance peak frequency shifts to high frequency, and the sound absorption performance of the resonance peak is improved.

[0036] Embodiment 2: In this example, a volute 1 integrated with a muffler 2 and a noise suppression method are proposed, wherein the volute 1 includes a muffler 2, the muffler 2 includes a muffler device 3 and a control device 4, the muffler device 3 includes a perforated plate 31, a resonance cavity 32, an outer wall plate 33, and a track groove 34, and the control device 4 includes a motor 41 and a partition 42. The noise suppression method is that the motor 41 receives a signal from an air compressor controller, changes the rotation angle of the partition 42 according to the speed, switches the perforation aperture and perforation rate of the muffler 2, realizes targeted noise suppression at different speeds, attenuates the noise energy at the significant rotational fundamental frequency of the air compressor, and effectively suppresses the noise transmission of the air compressor.

[0037] The air compressor has low aerodynamic noise at low speed, such as idle speed, and high aerodynamic noise at high speed, such as rated working condition and full load working condition. Therefore, the perforation diameter and perforation rate of the perforation structure should be set to correspond to the rotational fundamental frequency of the rated working condition and full load working condition of the air compressor, so that the aerodynamic noise under the two common working conditions can be well suppressed.

[0038] The motor 41 receives the signal from the air compressor controller, changes the rotation angle of the partition 42 according to the speed, switches to the perforated structure 311 matching the rated speed at the rated speed, and switches to the perforated structure 312 matching the full load speed at the full load speed, so that the significant rotational fundamental frequency aerodynamic noise generated by the airflow flowing through the outlet of the volute 1 resonates with the Helmholtz resonance cavity 32: the aperture wall produces damping and friction effects on the sound wave, attenuates the sound energy of the sound wave, reduces the energy of the sound wave, and suppresses the transmission of aerodynamic noise.

[0039] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0040] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A muffler integrated volute, characterized in that: The integrated volute (1) comprises a muffler (2), the muffler (2) comprising a muffler device (3) and a control device (4); the muffler device (3) comprises a perforated plate (31), a resonance cavity (32), and an outer wall plate (33) arranged from the inside to the outside, the perforated plate (31) being provided with a perforated structure, and a resonance cavity (32) being provided between the perforated plate (31) and the outer wall plate (33); The control device (4) comprises a motor (41) and a partition (42).

2. The integrated volute of a muffler according to claim 1, characterized in that: The silencer (3) is integrated at the outlet end of the volute (1).

3. The integrated volute of a muffler according to claim 1, characterized in that: The perforated plate surface is provided with a first perforated structure (311) and a second perforated structure (312); the first perforated structure has a perforated aperture diameter D1 and a perforation rate A1; the second perforated structure has a perforated aperture diameter D2 and a perforation rate A2.

4. The integrated volute of a muffler according to claim 3, characterized in that: The perforated structures (311) and the perforated structures (312) are alternately distributed every 60 degrees along the circumferential direction of the inner wall of the perforated plate.

5. The integrated volute of a muffler according to claim 1, characterized in that: The resonance cavity (32) is located between the perforated plate (31) and the outer wall plate (33); the distance between the perforated plate (31) and 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.

6. The integrated volute of a muffler according to claim 1, characterized in that: The outer radius R1 of the outer wall plate (33) is consistent with the outer radius R2 of the outlet of the volute (1).

7. The integrated volute of a muffler according to claim 1, characterized in that: The motor (41) is placed outside the outer wall plate (33); the output shaft of the motor (41) is meshed with a guide rail (421) on the partition plate (42) via a gear, and the angle of the partition plate (42) is switched by driving the motor (41).

8. The integrated volute of a muffler according to claim 1, characterized in that: The partition body is a hollow cylinder (422), whose outer radius R4 is consistent with 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) is provided with grooves of 60° in the circumferential direction at intervals of 120° along the circumferential direction; the outer wall of the partition (42) radially extends along the end face to form a cylinder (422) of length H1 and radius 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 consistent with the radius R1 of the outer wall plate (33).

9. A method for suppressing noise of a muffler integrated volute, characterized in that: In the method, a muffler integrated volute is used for an air compressor, the volute is the volute of the air compressor, the motor (41) receives a signal from an air compressor controller, changes the rotation angle of the partition (42) according to the air compressor speed, and then switches the perforation aperture and perforation rate of the muffler (2), thereby achieving 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.

10. The noise suppression method of the muffler integrated volute according to claim 9, characterized in that: 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 the rated speed, the partition is switched to the first perforated structure (311) matching the rated speed. When the air compressor is at full load speed, the partition is switched to the first perforated structure (312) matching the full load speed, so that the significant rotational fundamental frequency aerodynamic noise generated by the airflow flowing through the outlet of the volute (1) resonates with the Helmholtz resonance cavity (32) of the muffler: the aperture wall produces damping and friction effects 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 muffler effect.

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