A noise reduction sawtooth structure for a butterfly valve

Abstract

The application belongs to the technical field of butterfly valves, and discloses a noise reduction sawtooth structure for a butterfly valve, which comprises a valve pipeline, a butterfly valve body is fixedly installed in the inside of the valve pipeline, front tooth groups located in front of the butterfly valve body are fixedly installed on both sides of the inside of the valve pipeline, rear tooth groups located in rear of the butterfly valve body are fixedly installed on both sides of the inside of the valve pipeline, the front tooth groups and the rear tooth groups are arranged, the front tooth groups can increase the turbulence of the flow, and can inhibit the wall surface separation phenomenon of the jet flow to a certain extent, the rear tooth groups can cut the jet flow to a certain extent, can destroy the speed gradient distribution of the jet flow, can cut the large-scale vortex system structure into small-scale vortex system structure, and can accelerate the energy dissipation, so that the noise reduction effect is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of butterfly valves, and specifically relates to a noise reduction sawtooth structure for a butterfly valve, which is distributed on the inner wall of a pipeline and at the front and rear positions of a valve opening. Through the design of the number of teeth and the circumferential distribution angle, the large-scale turbulent structure can be accelerated to break, and a noise reduction effect of 2 dB to 5 dB can be achieved in the range of 200 Hz to 5 kHz. BACKGROUND

[0002] At present, the butterfly valve commonly used in the aircraft environmental control system has many noise reduction means in various forms. The existing typical low-noise design structures include a small hole grid noise reduction design structure, a metal sheet noise reduction design structure and a channel type noise reduction design structure. Firstly, the small hole grid noise reduction design structure can have a good noise reduction effect on the low-frequency part, but the sound pressure level is increased to a certain extent for the high-frequency part due to the increase of small-scale vortex structure. Secondly, the metal sheet noise reduction design structure cannot be dynamically adjusted according to the change of the valve deflection angle, and the metal sheet is easily subjected to fatigue fracture under the periodic reciprocating stress of the airflow in the valve. Finally, the channel type noise reduction design structure causes the jet flow to directly impact the groove, resulting in pressure rise at the position, and further causing the valve to be blocked and the flow to be reduced, which has a great influence on the aerodynamic performance of the valve. In view of the problems existing in the three typical noise reduction structure designs and in combination with the specific working environment of the environmental control system valve, the present application provides a noise reduction sawtooth structure for a butterfly valve. SUMMARY

[0003] The present application aims at the above problems, and provides a noise reduction sawtooth structure for a butterfly valve, which has the advantages of stable noise reduction.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a noise reduction sawtooth structure for a butterfly valve, comprising a valve pipeline, a butterfly valve body is fixedly installed in the inside of the valve pipeline, a front tooth group located in front of the butterfly valve body is fixedly installed on the front of both sides in the inside of the valve pipeline, and a rear tooth group located in rear of the butterfly valve body is fixedly installed on the rear of both sides in the inside of the valve pipeline.

[0005] As a preferred embodiment of the present application, the number of the front tooth groups is two, the sizes of the two front tooth groups are the same, and the two front tooth groups are symmetric about the center of the valve pipeline.

[0006] As a preferred embodiment of the present application, the number of the rear tooth groups is two, the sizes of the two rear tooth groups are the same, and the two rear tooth groups are symmetric about the center of the valve pipeline.

[0007] As a preferred embodiment of the present application, the inside of the front tooth group is composed of sawteeth, and the inside of the rear tooth group is composed of sawteeth.

[0008] As the application is preferred, the sawtooth opening angle inside the front tooth group is seven point five degrees, and the sawtooth opening angle inside the rear tooth group is seven point five degrees.

[0009] As the application is preferred, the tooth height of the sawtooth inside the front tooth group is three millimeters, and the tooth height of the sawtooth inside the rear tooth group is three millimeters.

[0010] Compared with the prior art, the application has the following beneficial effects:

[0011] 1. The front tooth group and the rear tooth group are arranged, the design of the front tooth group can increase the turbulence degree of the flow, and the wall separation phenomenon of the jet flow is inhibited to a certain extent, the design of the rear tooth group can cut the jet flow to a certain extent, the large-scale vortex structure is cut into small-scale vortex structure, the energy dissipation is accelerated, and the noise reduction effect is achieved.

[0012] 2. The front tooth group and the rear tooth group are arranged, the different tooth numbers inside the front tooth group and the rear tooth group can cut the jet flow in different ranges, the increase of the sawtooth number can expand the cutting effect on the jet flow, but the blocking effect on the flow is also strengthened, the decrease of the sawtooth number can reduce the blocking effect on the flow, and the cutting effect on the flow is also weakened, and the angle of the sawtooth inside the front tooth group and the rear tooth group can guarantee the structural strength of the sawtooth structure, and the structure can also guarantee the good cutting effect on the jet flow. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the application;

[0014] Figure 2 It is a structural schematic diagram of the side view of the application;

[0015] Figure 3 It is a structural schematic diagram of the top view of the application;

[0016] Figure 4 It is a sectional view structural schematic diagram of the front tooth group of the application;

[0017] Figure 5 It is a global Mach number distribution schematic diagram;

[0018] Figure 6 It is a local Mach number distribution schematic diagram;

[0019] Figure 7 It is a local density gradient distribution schematic diagram;

[0020] Figure 8Schematic diagram of global sound field distribution;

[0021] Figure 9 Schematic diagram of local sound field distribution;

[0022] Figure 10 Schematic diagram of unsteady calculation iteration;

[0023] Figure 11 Schematic diagram of Mach number distribution;

[0024] Figure 12 Time domain signal diagram at up_12 measuring point;

[0025] Figure 13 Power spectrum density comparison diagram at up_15 measuring point.

[0026] In the figure: 1, valve pipeline; 2, butterfly valve body; 3, front tooth group; 4, rear tooth group. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0028] As Figures 1 to 7 shown, the present application provides a noise reduction sawtooth structure for a butterfly valve, which comprises a valve pipeline 1, a butterfly valve body 2 fixedly installed inside the valve pipeline 1, a front tooth group 3 fixedly installed at the front of the butterfly valve body 2 on both sides inside the valve pipeline 1, and a rear tooth group 4 fixedly installed at the rear of the butterfly valve body 2 on both sides inside the valve pipeline 1.

[0029] Due to the design of the front tooth group 3, the main effect is to increase the turbulence of the incoming flow and to suppress the wall separation phenomenon of the jet flow to some extent. Due to the design of the rear tooth group 4, if the position of the rear tooth group 4 is relatively close to the valve, it will mainly play a certain cutting role on the Mach ring structure in the jet flow, destroying the velocity gradient distribution. If the position of the rear tooth group 4 is far from the valve, the sawtooth structure can mainly cut the large-scale vortex structure into small-scale vortex structure, which can achieve the effect of accelerating energy dissipation. Figure 5 It can be found that the jet flow deflects relatively late, and Figure 6 It can be found that the deflection angle of the lower lip jet flow is small, and an obvious expansion wave structure is generated at the rear side of the lower lip jet sawtooth structure. The velocity distribution before and after the section has a relatively obvious difference. Figure 7It can be found that a more obvious black line represents that the density gradient changes more sharply here, and there is a strong extrusion shear effect inside the fluid.

[0030] Reference Figures 1 to 4 and Figure 8 The number of the front tooth groups 3 is two, the sizes of the two front tooth groups 3 are the same, and the two front tooth groups 3 are symmetric about the center of the valve pipe 1.

[0031] As a technical optimization scheme of the application, the front tooth groups 3 are arranged, and due to the design of the two front tooth groups 3, the turbulence of the flow can be increased, and the wall separation phenomenon of the jet flow is inhibited to a certain extent, in combination with Figure 8 It can be found that the noise source is mainly concentrated in the middle and upper reaches, and is located around the two jets, and the reason is also obvious. In the high-speed jet flow, there is a large velocity gradient and shear, so it becomes the main noise source. It should be noted that the position in the center of the jet flow is not the position with the maximum noise, because although the jet flow speed is high at this position, the velocity gradient is not high, and the fluid shear effect is weak. It can be seen that the noise decibel number is high on both sides of the jet flow, because the velocity changes greatly at this position, the velocity gradient is high, and as the sawtooth structure moves backward, the deflection angle of the jet flow near the lower lip is small, so it will have an impact on a larger range of the downstream.

[0032] Reference Figures 1 to 4 and Figure 9 The number of the rear tooth groups 4 is two, the sizes of the two rear tooth groups 4 are the same, and the two rear tooth groups 4 are symmetric about the center of the valve pipe 1.

[0033] As a technical optimization scheme of the application, the rear tooth groups 4 are arranged, and due to the design of the two rear tooth groups 4, the jet flow is cut to a certain extent, the velocity gradient distribution is destroyed, and at the same time, the large-scale vortex structure can be cut into small-scale vortex structure, so that the energy dissipation can be accelerated, and the noise reduction effect can be achieved, in combination with Figure 9 It can be found that there is a more mixed flow structure in the middle and lower reaches of the valve, and the noise source is mainly located at the position with strong shear on both sides of the jet flow, and the main noise source is near the jet flow of the lower lip. Because of the existence of the backflow area and the relatively sharp change of the jet flow velocity, a strong shear effect is generated.

[0034] Reference Figures 1 to 4 and Figure 10 The inside of the front tooth groups 3 is composed of sawteeth, and the inside of the rear tooth groups 4 is composed of sawteeth.

[0035] As a technical optimization scheme of the present application, by setting the front tooth group 3 and the rear tooth group 4, since the front tooth group 3 and the rear tooth group 4 are both composed of sawteeth, different tooth numbers will correspond to cutting effects on different ranges of the jet flow, and the increase of the number of sawteeth will expand the cutting effect on the jet flow, but will also strengthen the blocking effect on the jet flow, and the decrease of the number of sawteeth will reduce the blocking effect on the jet flow, and will also weaken the cutting effect on the jet flow accordingly, in combination with Figure 10 It can be found that there is a relatively obvious Mach ring structure inside the pipeline, in this area, the fluid core flow speed is relatively high, the density gradient and the speed gradient are large, and it is a directional airflow with extremely high turbulence degree; at the same time, there is also a multi-scale vortex system structure inside the pipeline, and there are large and small vortex system structures around the jet flow core area, especially in the downstream area; in addition, it can be seen from the side views of the two that the sawteeth have a relatively obvious cutting effect on the jet flow, and the shearing effect of the fluid on the jet flow increases with the increase of the number of sawteeth.

[0036] Referring to Figures 1 to 4 and Figure 11 , the opening angle of the sawteeth inside the front tooth group 3 is seven and a half degrees, and the opening angle of the sawteeth inside the front tooth group 3 is seven and a half degrees.

[0037] As a technical optimization scheme of the present application, by setting the front tooth group 3 and the rear tooth group 4, since the opening angle of the sawteeth inside the front tooth group 3 and the rear tooth group 4 is seven and a half degrees, the structural strength of the sawtooth structure can be ensured, and the structure can also ensure that it can have a good cutting effect on the jet flow, in combination with Figure 11 It can be found that in the range of 0-6ms, the flow field is in a transition stage, and after 6ms, the time domain signal appears a quasi-periodic phenomenon, so for the frequency domain signal that follows, the data of 6-8ms is intercepted for analysis.

[0038] Referring to Figures 1 to 4 and Figures 12 to 13 , the tooth height of the sawteeth inside the front tooth group 3 is three millimeters, and the tooth height of the sawteeth inside the rear tooth group 4 is three millimeters.

[0039] As a technical optimization scheme of the present application, by setting the front tooth group 3 and the rear tooth group 4, since the tooth height of the sawteeth inside the front tooth group 3 and the rear tooth group 4 is three millimeters, the sawteeth can have a cutting effect on the jet flow core area, and since there is a gap between the sawteeth, the height will not block the jet flow, so a good noise reduction effect can be achieved, in combination with Figure 12It can be found that the flow is basically stable, therefore, the next focus will be on the analysis of the sound pressure level spectrum at these two points, and the noise reduction design with different noise reduction parameters will also be analyzed, from 200Hz to 4kHz, the frequency range that the human ear is more sensitive to, it can be seen that both noise reduction design structures have 2-4dB noise reduction effect, in the range of 4kHz to 7kHz, the sound pressure level of the 16serrations_0.25D example compared with the other two examples has a relatively obvious rise, here it may be due to the increase of the number of serrations, the cutting effect of serrations on the two jets is enhanced, relatively more large-scale vortex structure is broken into small-scale vortex structure, and thus more high-frequency component noise is radiated outward, above 7kHz, the sound pressure level of the two serration structure designs compared with the non-serration structure also has a certain degree of rise, combined with the above analysis, it can be seen that the serration structure can effectively reduce the noise of the valve, and the noise reduction effect is related to the number and position of serrations. Figure 13 It can be found that, from 200Hz to 5kHz, the frequency range that the human ear is more sensitive to, it can be seen that both noise reduction design structures have 2-6dB noise reduction effect, above 5kHz, it can be seen that the sound pressure level of the 16serrations_0.25D example compared with the other two examples has a relatively obvious rise, here it may be due to the increase of the number of serrations, the cutting effect of serrations on the two jets is enhanced, relatively more large-scale vortex structure is broken into small-scale vortex structure, and thus more high-frequency component noise is radiated outward, by using numerical method, the influence of the low noise design structure on the noise distribution inside the valve under different serration number and position parameters is studied, the obtained conclusion is that the sound pressure level inside the valve pipeline has certain relationship with the number and position of serrations, the low noise design structure can realize 3-5dB noise reduction effect in the range of 200Hz-5kHz, but due to the increase of small-scale vortex structure, the high-frequency component above 5kHz is increased.

[0040] The working principle and use process of the application are as follows:

[0041] Firstly, due to the design of the two front tooth groups 3, the incoming flow turbulence can be increased, and the wall separation phenomenon of the jet flow is inhibited to a certain extent, due to the design of the two rear tooth groups 4, the jet flow is cut to a certain extent, the velocity gradient distribution is destroyed, at the same time, the large-scale vortex structure is cut into small-scale vortex structure, so that the effect of accelerating energy dissipation is achieved, thereby the noise reduction effect is achieved.

[0042] Secondly, the different number of teeth in the front tooth group 3 and the rear tooth group 4 will correspond to the cutting effect on the jet flow in different ranges, the increase of the number of serrations will expand the cutting effect on the jet flow, but the blocking effect on the incoming flow will also be enhanced, the decrease of the number of serrations will reduce the blocking effect on the incoming flow, and at the same time, the cutting effect on the incoming flow will also be weakened accordingly.

[0043] Further, the opening angle of the sawtooth inside the front tooth group 3 and the rear tooth group 4 is 7.5 degrees, so as to ensure the structural strength of the sawtooth structure, and meanwhile, the structure can also ensure that the jet flow can be cut well.

[0044] Finally, the tooth height of the sawtooth inside the front tooth group 3 and the rear tooth group 4 is 3 mm, so as to cut the jet flow core area, and meanwhile, due to the existence of the gap between the sawteeth, the height will not block the jet flow, so as to achieve a better noise reduction effect, and the front tooth group 3 mainly functions in increasing the flow turbulence and suppressing the wall separation phenomenon of the jet flow to a certain extent. If the rear tooth group 4 is relatively close to the valve, it mainly functions in cutting the Mach ring structure in the jet flow to a certain extent, and destroying the velocity gradient distribution. If the rear tooth group 4 is far away from the valve, the sawtooth structure mainly cuts the large-scale vortex structure into small-scale vortex structure, so as to achieve the effect of accelerating energy dissipation.

[0045] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0046] Although the embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A noise-reducing sawtooth structure for a butterfly valve, comprising a valve duct (1), characterized in that: The butterfly valve body (2) is fixedly installed in the valve pipeline (1), the front tooth group (3) is fixedly installed in front of the butterfly valve body (2) on both sides of the inside of the valve pipeline (1), and the rear tooth group (4) is fixedly installed in rear of the butterfly valve body (2) on both sides of the inside of the valve pipeline (1). The front tooth group (3) increases the turbulence degree of the flow and inhibits the wall separation phenomenon of the jet flow; The rear tooth group (4) cuts the Mach ring structure in the jet flow and destroys the velocity gradient distribution; or the rear tooth group (4) cuts the large-scale vortex structure into small-scale vortex structure, so that the energy dissipation is accelerated.

2. The noise reduction sawtooth structure for a butterfly valve according to claim 1, wherein: The number of the front tooth group (3) is two, the sizes of the two front tooth groups (3) are same, and the two front tooth groups (3) are symmetric about the center of the valve pipeline (1).

3. The noise reduction sawtooth structure for a butterfly valve according to claim 1, wherein: The number of the rear tooth group (4) is two, the sizes of the two rear tooth groups (4) are same, and the two rear tooth groups (4) are symmetric about the center of the valve pipeline (1).

4. The noise reduction sawtooth structure for a butterfly valve according to claim 1, wherein: The inside of the front tooth group (3) is composed of sawteeth, and the inside of the rear tooth group (4) is composed of sawteeth.

5. The noise reduction sawtooth structure for a butterfly valve according to claim 1, wherein: The opening angle of the sawteeth in the front tooth group (3) is 7.5 degrees, and the opening angle of the sawteeth in the rear tooth group (4) is 7.5 degrees.

6. The noise reduction sawtooth structure for a butterfly valve according to claim 1, wherein: The tooth height of the sawteeth in the front tooth group (3) is 3 mm, and the tooth height of the sawteeth in the rear tooth group (4) is 3 mm.

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