Water jet propelling pump noise reduction structure

Abstract

The application discloses a water jet propelling pump noise reduction structure, which comprises a sleeve, more than one support cavity is arranged on the outer wall surface of the sleeve, a through hole penetrating through the outer wall surface of the sleeve is formed in the support cavity, a communication pipe is fixed at the through hole and is used for communicating the hollow part of the sleeve with the outside, a noise reduction unit matched with the support cavity is filled in the support cavity, a blind hole matched with the communication pipe is formed in the noise reduction unit, the noise reduction unit comprises a sound absorption block and an outer cladding layer completely wrapping the sound absorption block, the blind hole penetrates through the outer cladding layer and enters the sound absorption block, a hollow cavity is arranged in the sound absorption block, the hollow cavity is in the same straight line with the blind hole and the blind hole is not communicated with the hollow cavity, a noise reduction unit fixing device for fixing the noise reduction unit is further arranged outside the sleeve, the water jet propelling pump noise reduction structure is simple in structure, reasonable in design, large in sound absorption frequency range, good in noise reduction effect, low in cost and good in application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ship propulsion system noise reduction, and relates to a waterjet pump noise reduction structure. BACKGROUND

[0002] Acoustic stealth performance is crucial for high-speed ships and submarines. Improving stealth mainly approaches from two aspects, one is to control the generation of noise, and the other is to control the propagation of noise. In high-performance ships and submarines, the noise generated by the propeller is an important source of radiated noise. Compared with the propeller, the waterjet is more and more used in high-performance ships and submarines because of its stronger anti-cavitation ability and higher efficiency at high speed. Due to the dynamic and static interference, cavitation and other flow phenomena will cause the waterjet pump to generate noise, and then radiate noise to the external flow field through the pipe and the guide vane shell of the waterjet pump impeller chamber. Among them, the line spectrum noise generated by the dynamic and static interference is concentrated in the low frequency. Because the low frequency noise has the characteristic of long wavelength, its propagation ability is stronger. At the same time, the noise amplitude generated by the dynamic and static interference is often much higher than that of other frequencies, and it is more likely to be received by sonar, reducing the acoustic stealth of the ship. Therefore, reducing the noise radiated by the waterjet pump to the outside can reduce the noise of the entire vehicle.

[0003] Therefore, it is of great practical significance to develop a device that can effectively reduce the noise radiated by the waterjet pump to the outside. SUMMARY

[0004] Since the prior art has the above defects, the present application provides a device that can effectively reduce the noise radiated by the waterjet pump to the outside, specifically a waterjet pump noise reduction structure based on the concept of extended pipe acoustic metamaterial, which specifically reduces the radiated noise of the waterjet pump by reasonably designing the structural parameters of the acoustic covering material cavity and then applying the structural parameters to the positions of the waterjet pump impeller chamber, guide vane body and incoming flow pipe.

[0005] In order to achieve the above purpose, the present application provides the following technical scheme:

[0006] A waterjet pump noise reduction structure, comprising a sleeve;

[0007] The outer wall surface of the sleeve is provided with one or more support cavities, the support cavities are provided with through holes penetrating the outer wall surface of the sleeve, and the through holes are fixed with communication pipes communicating the hollow part of the sleeve with the outside, the support cavities are filled with noise reduction units matched with the support cavities, the noise reduction units are provided with blind holes matched with the communication pipes, the noise reduction units comprise sound absorption blocks and outer cladding layers completely wrapping the sound absorption blocks, the blind holes penetrate the outer cladding layers and then penetrate into the sound absorption blocks, the sound absorption blocks are provided with hollow cavities, the hollow cavities are on the same straight line with the blind holes and the blind holes are not communicated with the hollow cavities;

[0008] The sleeve is further provided with a noise reduction unit fixing device for fixing the noise reduction units.

[0009] The water jet propelling pump noise reduction structure of the present application, the design concept is to absorb the outward radiation sound wave of the water jet propeller into the noise reduction structure as much as possible and dissipate it to achieve the sound stealth effect of the water jet propeller. Specifically, the acoustic metamaterial based on the extended pipe concept is arranged in the support cavity, the communication pipe protrudes into the support cavity through the perforation, a Helmholtz resonant cavity is formed, the sound wave resonates in the cavity and is finally lost, this structure increases the impedance of the resonant cavity, hinders the propagation of noise, and thus reduces the outward radiation noise. By controlling the height of the resonant cavity, the amplitude of the reverse sound wave is opposite to that of the forward propagating sound wave at the same phase, thereby canceling the amplitude at the characteristic frequency and achieving the purpose of noise reduction. The hollow cavity in the sound absorption block is used to adjust the frequency corresponding to the maximum sound absorption coefficient. The greater the cavity depth, the lower the maximum sound absorption coefficient of the micro-perforated plate sound absorption body moves. The water jet propelling pump noise reduction structure of the present application can replace the original pipeline of the water jet propelling pump, and the noise reduction unit fixing device can fix the noise reduction unit to ensure that the noise reduction unit blocks the open end of the communication pipe.

[0010] As a preferred technical solution:

[0011] The water jet propelling pump noise reduction structure as described above, the support cavities are multiple and uniformly distributed on the outer wall surface of the sleeve.

[0012] The water jet propelling pump noise reduction structure as described above, the support cavities are square, of course, the specific shape of the support cavities can be set by those skilled in the art according to actual needs, here only one feasible technical solution is given;

[0013] The sleeve is made of metal material, specifically 304 stainless steel.

[0014] The water jet propelling pump noise reduction structure as described above, the noise reduction unit fixing device is a ring-shaped flexible sealing ring, the ring-shaped flexible sealing ring is sleeved outside the sleeve and the ring-shaped flexible sealing ring is located outside the noise reduction unit.

[0015] The water jet propelling pump noise reduction structure as described above, the material of the ring-shaped flexible sealing ring is vulcanized styrene-butadiene rubber, which has high characteristic impedance and good damping and buffering effect. When it is attached to the pipeline or the shell of the pump, it plays a role in impedance transition on the basis of damping and noise reduction.

[0016] The water jet propelling pump noise reduction structure as described above, the material of the sound absorption block is elastomeric polyurethane, which is a viscoelastic material, and its sound absorption mechanism mainly causes molecular internal friction and sound wave dissipation at different medium interfaces.

[0017] The water jet propelling pump noise reduction structure as described above, the communication pipe is arranged in the center of the support cavity and coaxial with the support cavity.

[0018] The water jet propelling pump noise reduction structure as described above, the hollow cavity is a rectangular structure and coaxial with the blind hole.

[0019] The above technical solution is only one possible technical solution of the present application, and the protection scope of the present application is not limited to this. Those skilled in the art can reasonably adjust the specific design according to actual needs.

[0020] The above-mentioned application has the following advantages or beneficial effects:

[0021] (1) The water jet propelling pump noise reduction structure of the present application has simple structure, simple preparation and low cost.

[0022] (2) The water jet propelling pump noise reduction structure of the present application has reasonable structure design, large sound absorption frequency range and good noise reduction effect, and has great application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application and its features, shapes and advantages will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings. The same reference signs indicate the same parts throughout the drawings. The drawings are not drawn to scale, the emphasis being on illustrating the main idea of the present application.

[0024] Figure 1 It is a model diagram of a water jet propelling pump;

[0025] Figure 2 It is a structural schematic diagram of the water jet propelling pump noise reduction structure of the present application;

[0026] Figure 3 It is a schematic diagram of the water jet propelling pump noise reduction structure of the present application removing part of the annular flexible sealing ring;

[0027] Figure 4 It is a schematic diagram of the water jet propelling pump noise reduction structure of the present application removing the annular flexible sealing ring;

[0028] Figure 5 It is a structural schematic diagram of the sleeve;

[0029] Figure 6 It is a schematic diagram of the support cavity;

[0030] Figure 7 It is a schematic diagram of the noise reduction unit and the annular flexible sealing ring;

[0031] Figure 8 It is a schematic diagram of the noise reduction unit;

[0032] Figure 9The following are comparison diagrams showing the noise reduction effect before and after using the water jet propulsion pump noise reduction structure of the present invention: (a) shows the noise reduction effect before using the water jet propulsion pump noise reduction structure of the present invention, and (b) shows the noise reduction effect after using the water jet propulsion pump noise reduction structure of the present invention.

[0033] Among them, 1 is the sleeve, 2 is the support cavity, 3 is the connecting pipe, 4 is the noise reduction unit, 41 is the sound absorption block, 42 ​​is the outer cladding, 43 is the blind hole, 44 is the hollow cavity, and 5 is the annular flexible sealing ring. Detailed Implementation

[0034] The structure of the present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0035] Example 1

[0036] A noise reduction structure for a water jet propulsion pump, such as Figures 2 to 7 As shown, it includes a sleeve (metal material, 304 stainless steel shell);

[0037] The outer wall of the sleeve is provided with multiple support cavities (square) evenly distributed on the outer wall of the sleeve. The support cavity has a through hole that penetrates the outer wall of the sleeve, and a connecting pipe that connects the hollow part of the sleeve to the outside is fixed at the through hole. The connecting pipe is arranged in the center of the support cavity and is coaxial with the support cavity. The support cavity is filled with a noise reduction unit that matches the support cavity. The noise reduction unit has a blind hole that matches the connecting pipe. The noise reduction unit includes a sound-absorbing block (made of elastomer polyurethane) and an outer layer that completely covers the sound-absorbing block. The blind hole penetrates the outer layer and enters the sound-absorbing block. The sound-absorbing block has a hollow cavity (rectangular structure) that is coaxial with the blind hole. The hollow cavity and the blind hole are on the same straight line and the blind hole and the hollow cavity are not connected.

[0038] The outer sleeve is fitted with an annular flexible sealing ring (made of vulcanized styrene-butadiene rubber), and the annular flexible sealing ring is located on the outside of the noise reduction unit to fix the noise reduction unit in the support cavity.

[0039] Specifically, the noise reduction structure of the water jet propulsion pump of the present invention is applied to, for example... Figure 1 The water jet propulsion pump shown (which includes a suction pipe, main shaft, impeller, guide vanes, and impeller chamber; the noise generated inside the pump is mainly radiated outward through the suction pipe, impeller chamber, and guide vane chamber) (replace) Figure 1 The left pipe in the middle), the water jet propulsion pump has a speed of 1450 r / min, 5 impeller blades, 9 guide vane blades, and the main frequency of pressure pulsation caused by dynamic and static interference is 120.8 Hz, and the corresponding main frequency of radiated noise is 120.8 Hz.

[0040] The support cavity is manufactured using laser cutting, and the noise reduction unit (such as...) Figure 8The structural parameters of the structure shown in the figure are as follows: a=0.033 mm; h=0.057 mm; t1=0.004 mm; t2=0.001 mm; t3=0.01 mm; t4=0.0005 mm; d=0.0028 mm; and l=0.036 mm.

[0041] Radiation noise before and after using the noise reduction structure is tested (noise one meter away from the outside of the water jet propulsion pump is measured by horizontally placed microphones), and the specific operation is as follows: before using the noise reduction structure, specifically using the original water jet propulsion pump, after using the noise reduction structure, specifically using the water jet propulsion pump noise reduction structure of the application to replace the left pipe in Figure 1 The test results are shown in Figure 9 It can be found by comparison that the sound pressure at the main frequency 120.8 Hz caused by the dynamic and static interference is significantly reduced after using the water jet propulsion pump noise reduction structure of the application.

[0042] Those skilled in the art should understand that those skilled in the art can realize the variation examples in combination with the prior art and the above-mentioned embodiments, which are not described here. Such variation examples do not affect the essential content of the application, and are not described here.

[0043] The preferred embodiments of the application are described above. It should be understood that the application is not limited to the above specific embodiments, and the devices and structures not fully described should be understood as being implemented in the ordinary way in the art; any person skilled in the art can make many possible changes and modifications to the technical solutions of the application by using the disclosed methods and technical contents without departing from the scope of the technical solutions of the application, or modify equivalent embodiments of equivalent changes, which do not affect the essential content of the application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the application, without departing from the content of the technical solutions of the application, still belongs to the scope of protection of the technical solutions of the application.

Claims

1. A waterjet pump noise reduction structure, characterized by: The sleeve comprises a casing; The outer wall surface of the sleeve is provided with one or more support cavities, the support cavities are provided with through holes penetrating the outer wall surface of the sleeve, the through holes are fixed with communication pipes for communicating the hollow part of the sleeve with the outside, the support cavities are filled with noise reduction units matched with the support cavities, the noise reduction units are provided with blind holes matched with the communication pipes, the noise reduction units comprise sound absorption blocks and outer cladding layers completely wrapping the sound absorption blocks, the blind holes penetrate the outer cladding layers and then penetrate into the sound absorption blocks, the sound absorption blocks are provided with hollow cavities, the hollow cavities are in the same straight line with the blind holes and the blind holes are not communicated with the hollow cavities; The sleeve is further provided with a noise reduction unit fixing device for fixing the noise reduction units.

2. The waterjet pump noise reduction structure of claim 1, wherein, The support cavities are multiple and uniformly distributed on the outer wall surface of the sleeve.

3. The waterjet pump noise reduction structure of claim 2, wherein, The support cavities are square. The sleeve is made of metal.

4. The waterjet pump noise reduction structure of claim 1, wherein, The noise reduction unit fixing device is a ring-shaped flexible sealing ring, the ring-shaped flexible sealing ring is sleeved on the outside of the sleeve and located on the outside of the noise reduction units.

5. The waterjet pump noise reduction structure of claim 4, wherein, The material of the ring-shaped flexible sealing ring is vulcanized styrene-butadiene rubber.

6. The waterjet pump noise reduction structure of claim 1, wherein The material of the sound absorption blocks is elastomeric polyurethane.

7. The waterjet pump noise reduction structure of claim 1, wherein The communication pipes are arranged at the center of the support cavities and coaxial with the support cavities.

8. The waterjet pump noise reduction structure of claim 7, wherein, The hollow cavities are rectangular structures and coaxial with the blind holes.

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