Silencing device, aero-engine and aircraft

Abstract

The utility model relates to a silencer, an aero-engine and an aircraft, belongs to the technical field of aerospace, and solves the problem that a silencer which is low in cost and capable of efficiently silencing is difficult to arrange in a small space in the prior art. The device comprises a waste gas inlet pipe, an expansion cavity and a vibration eliminating structure, one side of the expansion cavity communicates with a waste gas inlet pipe, and the other side of the expansion cavity communicates with a vibration eliminating structure; the vibration eliminating structure and the waste gas inlet pipe are positioned on the same axis; the vibration eliminating structure comprises a resonant frequency eliminating pipe and a silencing disc; and the silencing disc is arranged in the resonant frequency eliminating pipe. The utility model discloses can reduce cost, save space and efficient noise reduction.

Description

Technical Field

[0001] This utility model relates to the field of aerospace technology, and in particular to a noise reduction device, an aero-engine, and an aircraft. Background Technology

[0002] Currently, piston-type aircraft engines used in drones often generate tremendous noise. However, the silencers for imported aircraft engines are expensive, the internal space of aircraft engines is small, and drones themselves have lightweight requirements. Therefore, it is an urgent problem to solve the issue of setting up a low-cost and efficient silencer in a small space. Utility Model Content

[0003] Based on the above analysis, the present invention aims to provide a muffler, an aircraft engine, and an aircraft to solve the problem of difficulty in installing a low-cost and efficient muffler in a small space.

[0004] The objective of this utility model is mainly achieved through the following technical solutions:

[0005] This utility model provides a silencing device, including an exhaust gas inlet pipe, an expansion chamber, and a vibration elimination structure; one side of the expansion chamber is connected to the exhaust gas inlet pipe, and the other side of the expansion chamber is connected to the vibration elimination structure;

[0006] The vibration elimination structure includes a resonant frequency elimination tube and a noise-absorbing disk; the noise-absorbing disk is disposed inside the resonant frequency elimination tube.

[0007] Furthermore, the resonant frequency elimination pipe and the exhaust gas inlet pipe are located on the same axis.

[0008] Furthermore, the wall thickness of the expansion chamber is less than the wall thickness of the exhaust gas inlet pipe.

[0009] Furthermore, the inner diameter of the resonant frequency elimination tube is smaller than the inner diameter of the exhaust gas inlet pipe.

[0010] Furthermore, the resonant frequency elimination tube has a closed end, and the silencing disk is disposed near the closed end.

[0011] Furthermore, it also includes a housing, wherein the exhaust gas inlet pipe, the expansion chamber, and the resonant frequency elimination pipe are all disposed inside the housing.

[0012] Furthermore, it also includes an exhaust gas outlet pipe, which and the exhaust gas inlet pipe are respectively disposed at both ends of the housing; the exhaust gas outlet pipe is connected to the expansion chamber, and the exhaust gas outlet pipe and the resonant frequency elimination pipe are disposed on the same side.

[0013] Furthermore, it also includes sound-absorbing cotton;

[0014] The exhaust gas inlet pipe has a silencer hole on the inner wall of the housing, and the silencer cotton is wrapped around part of the outside of the silencer hole; the length of the silencer cotton wrapping is 1 / 2 to 3 / 4 of the wall length of the silencer hole.

[0015] The exhaust gas outlet pipe is provided with an exhaust gas outlet pipe silencer hole on the inner wall of the shell, and the silencer cotton is wrapped around part of the outside of the exhaust gas outlet pipe silencer hole; the length of the silencer cotton wrapping is 1 / 2-3 / 4 of the wall length of the exhaust gas outlet pipe silencer hole.

[0016] A second aspect of this utility model is to provide an aircraft engine, including the aforementioned muffler.

[0017] A third aspect of this invention provides an aircraft including the aforementioned engine.

[0018] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0019] (1) Compared with the prior art, this utility model sets a connected vibration elimination structure on one side of the expansion cavity, replacing the method of increasing the wall thickness of the expansion cavity to eliminate vibration, thereby reducing costs, saving space, and improving noise reduction performance. In this utility model, the silencer disc is set in the resonant frequency elimination tube. Part of the exhaust gas enters the resonant frequency elimination tube from the exhaust gas inlet pipe, and the other part enters the expansion cavity. The exhaust gas entering the resonant frequency elimination tube is reflected by the bottom of the silencer disc and the resonant frequency elimination tube, forming an exhaust gas counter-current at the end of the expansion cavity with the airflow of the exhaust gas inlet pipe, thus eliminating the resonance of the airflow. The exhaust gas entering the expansion cavity causes the expansion cavity to vibrate. The setting of the resonant frequency elimination tube increases the stiffness of the expansion cavity, raises the resonant frequency point of the expansion cavity, and cancels the vibration of the expansion cavity. This utility model does not need to increase the wall thickness of the expansion cavity to increase the weight of the silencer, or set multiple expansion cavities to increase the volume of the silencer to eliminate vibration. By setting a vibration silencing structure on one side of the expansion cavity, compared with a silencer with the same noise reduction effect, the volume and weight are reduced by 1 / 3.

[0020] (2) The resonant frequency elimination tube and the exhaust gas inlet tube are on the same axis so that the exhaust gas entering the resonant frequency elimination tube is fully reflected by the silencer and the bottom of the resonant frequency elimination tube, effectively absorbing low-frequency vibrations, and high-frequency vibrations are effectively reflected by the resonant frequency elimination tube.

[0021] (3) In this utility model, the wall thickness of the expansion cavity is small, the vibration of the expansion cavity is obvious, and the silencing disk is far away from the expansion cavity, so that the combination of the resonant frequency elimination tube and the silencing disk has a better effect on the cancellation of vibration; the inner diameter of the resonant frequency elimination tube is small, which is conducive to achieving a better vibration reduction effect with minimal weight.

[0022] (4) In this utility model, the shell is set outside the expansion chamber, which is equivalent to a larger expansion chamber. The exhaust gas enters the shell from the silencer hole of the exhaust gas inlet pipe, the volume increases, the exhaust gas flow rate decreases, and the exhaust gas energy also decreases.

[0023] (5) In this utility model, the exhaust gas outlet pipe and the exhaust gas inlet pipe are respectively located at both ends of the shell and on different sides, which can increase the space of the expansion chamber within a limited space and reduce the energy of the exhaust gas to the greatest extent.

[0024] (6) In this utility model, the exhaust gas enters the muffler housing through the silencer holes of the exhaust gas inlet pipe and the exhaust gas outlet pipe. In addition, the exhaust gas plays a role in reducing speed and frequency after passing through the silencer holes. The length of the sound-absorbing cotton wrapping accounts for 1 / 2 to 3 / 4 of the length of the wall surface of the silencer hole of the exhaust gas inlet pipe and the wall surface of the silencer hole of the exhaust gas outlet pipe. If it is too small, the contact area of ​​the sound-absorbing cotton will be reduced, resulting in poor high-frequency noise elimination effect. If it is too large, the internal exhaust gas cannot smoothly enter the expansion chamber.

[0025] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages will become apparent from the description or be learned by practicing this invention. The objectives and other advantages of this invention can be realized and obtained from the details specifically pointed out in the text and accompanying drawings. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0027] Figure 1 This is a schematic diagram of the external structure of the silencing device in Example 1;

[0028] Figure 2 This is a schematic diagram of the internal structure of the silencer device in Example 1;

[0029] Figure 3 This is a schematic diagram of the structure of the silencer disc in Example 1.

[0030] Figure label:

[0031] 1-Shell, 2-Exhaust gas inlet pipe, 21-Exhaust gas inlet pipe silencer hole, 3-Exhaust gas outlet pipe, 31-Exhaust gas outlet pipe silencer hole, 4-Expansion chamber, 5-Vibration elimination structure, 51-Resonance frequency elimination pipe, 52-Silencer disc, 6-Silencer cotton. Detailed Implementation

[0032] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0033] Example 1

[0034] A specific embodiment of this utility model is as follows: Figure 1 and Figure 2 As shown, a noise reduction device is disclosed, including an exhaust gas inlet pipe 2, an expansion chamber 4, and a vibration elimination structure 5; one side of the expansion chamber 4 is connected to the exhaust gas inlet pipe 2, and the other side of the expansion chamber 4 is connected to the vibration elimination structure 5;

[0035] The vibration elimination structure 5 includes a resonant frequency elimination tube 51 and a noise reduction disk 52; the noise reduction disk 52 is disposed inside the resonant frequency elimination tube 51.

[0036] Furthermore, it also includes a housing 1, an exhaust gas inlet pipe 2, an expansion chamber 4, and a resonance frequency elimination pipe 51, all of which are disposed inside the housing 1.

[0037] The end face of the shell 1 is elliptical. The shell 1 is located outside the expansion chamber 4, which is equivalent to a larger expansion chamber 4. When the exhaust gas enters the shell 1, the volume increases, the exhaust gas flow rate decreases, and the exhaust gas energy also decreases.

[0038] Furthermore, it also includes an exhaust gas outlet pipe 3. The exhaust gas outlet pipe 3 and the exhaust gas inlet pipe 2 are respectively located at both ends of the housing 1. The inner diameter and length of the exhaust gas outlet pipe 3 are the same as those of the exhaust gas inlet pipe 2.

[0039] The exhaust gas outlet pipe 3 is connected to the expansion chamber 4 and is located on the same side as the resonant frequency elimination pipe 51. The exhaust gas outlet pipe 3 and the exhaust gas inlet pipe 2 are located at opposite ends of the housing 1, which increases the space of the expansion chamber 4 within a limited space and minimizes the energy of the exhaust gas.

[0040] Furthermore, both the exhaust gas inlet pipe 2 and the exhaust gas outlet pipe 3 are provided with silencer holes 21 and 31 on their walls. The exhaust gas enters the housing 1 through the silencer holes 21 and 31 of the exhaust gas inlet pipe and the silencer holes 31 of the exhaust gas outlet pipe. After passing through the silencer holes, the exhaust gas slows down and reduces its frequency.

[0041] It also includes sound-absorbing cotton 6, which wraps around the exterior of the exhaust gas inlet pipe 2 and the exhaust gas outlet pipe 3. To achieve a good sound absorption effect, the length of the sound-absorbing cotton 6 should be 1 / 2 to 3 / 4 of the length of the exhaust gas inlet pipe 2 and the exhaust gas outlet pipe 3. If the wrapping length is too short, the contact area of ​​the sound-absorbing cotton 6 will be reduced, resulting in poor high-frequency noise elimination; if the wrapping length is too long, the internal exhaust gas cannot smoothly enter the housing 1. Preferably, the length of the sound-absorbing cotton 6 should be 2 / 3 of the length of the exhaust gas inlet pipe 2 and the exhaust gas outlet pipe 3.

[0042] Expansion chamber 4 is located between exhaust gas inlet pipe 2 and exhaust gas outlet pipe 3, with one end connected to exhaust gas inlet pipe 2 and the other end connected to exhaust gas outlet pipe 3. The capacity of expansion chamber 4 is larger than that of exhaust gas inlet pipe 2 and exhaust gas outlet pipe 3. After exhaust gas enters expansion chamber 4, the exhaust gas flow rate decreases due to the increased space, and the energy of the exhaust gas decreases.

[0043] Furthermore, considering the weight reduction requirements of aero engines, the wall thickness of the expansion chamber 4 can be set to be less than the wall thickness of the exhaust gas inlet pipe 2.

[0044] The vibration elimination structure 5 includes a resonant frequency elimination tube 51 and a noise-absorbing disk 52. For example... Figure 3 As shown, the silencing disc 52 is a porous disc-shaped body, disposed inside the resonant frequency elimination tube 51. The resonant frequency elimination tube 51 is connected to the expansion cavity 4, located at one end of the exhaust gas inlet pipe 2, and on the same side as the exhaust gas outlet pipe 3. The end of the resonant frequency elimination tube 51 away from the expansion cavity 4 is closed. The silencing disc 52 is used to reflect exhaust gas and absorb low-frequency noise, and together with the resonant frequency elimination tube 51, it produces a vibration damping effect.

[0045] When exhaust gas enters the resonant frequency elimination pipe 51, the silencer 52 absorbs some of the low-frequency noise, while the high-frequency noise reaches the closed end of the resonant frequency elimination pipe 51 and is reflected, resonating with the high-frequency exhaust gas entering from the exhaust gas inlet pipe 2. For more efficient reflection and frequency absorption, preferably, the vibration elimination structure 5 and the exhaust gas inlet pipe 2 are located on the same axis.

[0046] Because the wall thickness of expansion chamber 4 is relatively small, the vibration generated when exhaust gas enters and flows in expansion chamber 4 is relatively large. In order to better eliminate resonance, the silencer 52 is set at the closed end of the near-resonance frequency elimination pipe 51, which is far away from expansion chamber 4, so that the combination of resonance frequency elimination pipe 51 and silencer 52 has a better effect on vibration cancellation.

[0047] Furthermore, the inner diameter of the resonant frequency elimination pipe 51 is smaller than the inner diameter of the exhaust gas inlet pipe 2. The small inner diameter of the resonant frequency elimination pipe 51 is beneficial for achieving vibration reduction with minimal weight.

[0048] Furthermore, it also includes sound-absorbing cotton 6. The exhaust gas inlet pipe 2 is provided with an exhaust gas inlet pipe silencer hole 21 on the inner wall of the housing 1, and the sound-absorbing cotton 6 is wrapped around part of the exterior of the exhaust gas inlet pipe silencer hole 21; the wrapping length of the sound-absorbing cotton 6 accounts for 1 / 2-3 / 4 of the wall length of the exhaust gas inlet pipe silencer hole 21; preferably, the wrapping length of the sound-absorbing cotton 6 accounts for 1 / 4 of the wall length of the exhaust gas inlet pipe silencer hole 21.

[0049] The exhaust outlet pipe 3 is provided with an exhaust outlet pipe silencer hole 31 on the inner wall of the housing 1. Silencing cotton 6 is wrapped around part of the exterior of the exhaust outlet pipe silencer hole 31; the length of the silencing cotton 6 is 1 / 2 to 3 / 4 of the wall length of the exhaust outlet pipe silencer hole 31. Preferably, the length of the silencing cotton 6 is 1 / 3 of the wall length of the exhaust outlet pipe silencer hole 31.

[0050] Preferably, since the energy is greatest when the exhaust gas enters the housing 1 through the exhaust gas inlet pipe 2, the sound-absorbing cotton 6 is placed at one end of the exhaust gas inlet pipe 2 near the expansion chamber 4 in order to allow the exhaust gas to enter the housing 1 as quickly and in the largest possible amount as quickly as possible. To allow the exhaust gas to pass through the exposed portion into the exhaust gas outlet pipe 3, and then pass through the sound-absorbing cotton 6 again to eliminate the high-frequency exhaust gas, the sound-absorbing cotton 6 is placed on the side of the exhaust gas outlet pipe 3 away from the expansion chamber 4.

[0051] When exhaust gas enters the exhaust gas inlet pipe 2, part of it enters the interior of the housing 1 through the silencer hole of the exhaust gas inlet pipe 2, and part of it enters the resonant frequency elimination pipe 51 and the expansion chamber 4 along the exhaust gas inlet pipe 2 through the silencer hole.

[0052] The exhaust gas velocity decreases as it passes through the silencing holes. Simultaneously, high-frequency and low-frequency exhaust gases come into contact with the sound-absorbing cotton 6 outside the silencing holes, further reducing the frequency and energy of the exhaust gas. The shell 1 is a large expansion cavity 4, which effectively reduces the exhaust gas velocity, thereby lowering the overall exhaust gas energy.

[0053] After the exhaust gas enters through the gap between the exhaust gas inlet pipe 2 and the shell 1, it bounces back to the part of the exhaust gas outlet pipe 3 that is not covered by the sound-absorbing cotton 6, and interacts with the exhaust gas flowing from the exhaust gas inlet pipe 2 and the shell 1, thereby reducing the energy and frequency of the exhaust gas entering from the space between the exhaust gas inlet pipe 2 and the shell 1.

[0054] At the point where the exhaust gas outlet pipe 3 is not covered by the sound-absorbing cotton 6, the exhaust gas entering the shell 1 is slowed down and cooled by the expansion space, and merges with the rebounding exhaust gas to further reduce energy and frequency; the exhaust gas enters the interior of the exhaust gas outlet pipe 3 through the point where the exhaust gas outlet pipe 3 is not covered by the sound-absorbing cotton 6.

[0055] The exhaust gas in the exhaust inlet pipe 2 that does not enter the shell 1 is decelerated and frequency-reduced by the wall silencing holes before entering the expansion chamber 4. After being silenced and decelerated by the silencing disk 52, it enters the closed end of the resonant frequency elimination pipe 51. At the bottom of the closed end, it rebounds towards the expansion chamber 4, and during the rebound, it is again decelerated and frequency-reduced by the silencing disk 52, counteracting the energy entering the expansion chamber 4 from the exhaust inlet pipe 2. This fully cancels out the energy and reduces the frequency before entering the inner cavity of the expansion chamber 4. Because the inner diameter of the expansion chamber 4 increases after entering, the flow velocity decreases again, and the energy decreases again.

[0056] The exhaust gas in the expansion chamber 4 and the exhaust gas entering the exhaust pipe 3 from the part not covered by the sound-absorbing cotton 6 are fully mixed in the exhaust pipe 3, and the speed is reduced, the temperature is reduced, and the frequency is reduced again. The exhaust gas is then silenced by the sound-absorbing holes and the sound-absorbing cotton 6, and finally discharged from the exhaust pipe 3.

[0057] After multiple rounds of frequency reduction, speed reduction, and temperature reduction, the exhaust gas is finally discharged, and the energy is significantly reduced.

[0058] Compared to existing technologies, this embodiment provides a connected vibration damping structure 5 on one side of the expansion cavity 4, avoiding the need to increase the wall thickness of the expansion cavity 4 to achieve vibration reduction, which would not meet the lightweight requirements of engines and aircraft. This reduces costs, saves space, and improves noise reduction performance. This embodiment does not increase the weight of the muffler by increasing the wall thickness of the expansion cavity, or increase the volume of the muffler by setting multiple expansion cavities to dampen vibration. By providing a vibration damping structure on one side of the expansion cavity, the volume and weight are reduced by one-third compared to mufflers with the same noise reduction effect.

[0059] In this embodiment, the silencing disc 52 is disposed within the resonant frequency elimination tube 51. The resonant frequency elimination tube 51 and the exhaust gas inlet pipe 2 are on the same axis. Part of the exhaust gas enters the resonant frequency elimination tube 51 from the exhaust gas inlet pipe 2, and the other part enters the expansion chamber 4. The exhaust gas entering the resonant frequency elimination tube 51 is reflected by the silencing disc 52, absorbing low-frequency vibrations, while high-frequency vibrations are reflected by the resonant frequency elimination tube 51, forming an airflow counter-current at the end of the expansion chamber 4 with the airflow from the exhaust gas inlet pipe 2, thus eliminating airflow resonance. The exhaust gas entering the expansion chamber 4 causes the expansion chamber 4 to vibrate. The placement of the resonant frequency elimination tube 51 increases the stiffness of the expansion chamber 4, raises the resonant frequency point of the expansion chamber 4, cancels the vibration of the expansion chamber 4, and improves the silencing effect. Actual verification shows that the silencing effect at a 1-meter measurement point decreased from 110 decibels to 89 decibels.

[0060] Example 2

[0061] This embodiment discloses an aircraft engine, including the muffler device of Embodiment 1.

[0062] Compared with the prior art, the advantages of the aircraft engine in this utility model embodiment are the same as those of the above-mentioned muffler, and will not be repeated here.

[0063] Example 3

[0064] This embodiment discloses an aircraft, including the aircraft engine of Embodiment 2.

[0065] Compared with the prior art, the advantages of the aircraft in this utility model embodiment are the same as those of the above-mentioned silencer and aero-engine, and will not be repeated here.

[0066] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A sound attenuating device, characterized in that The muffler comprises an exhaust inlet pipe (2), an expansion chamber (4) and a vibration elimination structure (5); one side of the expansion chamber (4) is communicated with the exhaust inlet pipe (2), and the other side of the expansion chamber (4) is communicated with the vibration elimination structure (5); The vibration elimination structure (5) comprises a resonance frequency elimination pipe (51) and a sound elimination disc (52); the sound elimination disc (52) is arranged in the resonance frequency elimination pipe (51).

2. The sound attenuating device of claim 1, wherein, The resonance frequency elimination pipe (51) is located on the same axis as the exhaust inlet pipe (2).

3. The sound attenuating device of claim 1, wherein, The wall thickness of the expansion chamber (4) is smaller than that of the exhaust inlet pipe (2).

4. The sound attenuating device of claim 1, wherein, The inner diameter of the resonance frequency elimination pipe (51) is smaller than that of the exhaust inlet pipe (2).

5. A sound attenuating device according to claim 3 or 4, characterised in that, The resonance frequency elimination pipe (51) has a closed end; the sound elimination disc (52) is arranged near the closed end.

6. The sound attenuating device of claim 1, wherein, The muffler further comprises a shell (1); the exhaust inlet pipe (2), the expansion chamber (4) and the resonance frequency elimination pipe (51) are arranged in the shell (1).

7. The sound attenuating device of claim 6, wherein, The muffler further comprises an exhaust outlet pipe (3); the exhaust outlet pipe (3) and the exhaust inlet pipe (2) are arranged at two ends of the shell (1) respectively; the exhaust outlet pipe (3) is communicated with the expansion chamber (4), and the exhaust outlet pipe (3) and the resonance frequency elimination pipe (51) are arranged on the same side.

8. The sound attenuating device of claim 7, wherein, The muffler further comprises sound elimination cotton (6). The exhaust inlet pipe (2) is provided with exhaust inlet pipe sound elimination holes (21) on the wall surface in the shell (1); the sound elimination cotton (6) is wrapped outside part of the exhaust inlet pipe sound elimination holes (21); the wrapping length of the sound elimination cotton (6) accounts for 1 / 2-3 / 4 of the wall surface length of the exhaust inlet pipe sound elimination holes (21). The exhaust outlet pipe (3) is provided with exhaust outlet pipe sound elimination holes (31) on the wall surface in the shell (1); the sound elimination cotton (6) is wrapped outside part of the exhaust outlet pipe sound elimination holes (31); the wrapping length of the sound elimination cotton (6) accounts for 1 / 2-3 / 4 of the wall surface length of the exhaust outlet pipe sound elimination holes (31).

9. An aeroengine characterised in that, The muffler comprises the sound elimination device according to any one of claims 1-8.

10. An aircraft characterized by, The muffler comprises the aero-engine according to claim 9.

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