CN211667379U - Variable cross-section silencer - Google Patents
Variable cross-section silencer Download PDFInfo
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- CN211667379U CN211667379U CN201922374799.1U CN201922374799U CN211667379U CN 211667379 U CN211667379 U CN 211667379U CN 201922374799 U CN201922374799 U CN 201922374799U CN 211667379 U CN211667379 U CN 211667379U
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Abstract
The utility model provides a variable cross section silencer, including relative first cut-off frequency face and the relative antetheca and the back wall and the transition face that set up of second cut-off frequency face, relative setting, the wherein both sides of transition face connect respectively in first cut-off frequency face and second cut-off frequency face, the other both sides of transition face connect respectively in antetheca and back wall, the length of first cut-off frequency face is less than the length of second cut-off frequency face, first cut-off frequency face, second cut-off frequency face, antetheca, back wall and transition face enclose to close the trapezoidal chamber silencer that forms to have the sound wave entry, the transition face with the sound wave entry is just to setting up. The utility model provides a variable cross section silencer, the cross-section from first cut-off frequency face to second cut-off frequency face constantly changes, has the different quarter wavelength pipe silencer of a plurality of lengths in other words, consequently can the wide band noise elimination, can not influence the air current moreover and flow.
Description
Technical Field
The utility model belongs to the technical field of pneumatic noise, more specifically say, relate to a variable cross section silencer.
Background
The quarter-wave tube silencer is a classic anti-type silencer, has the advantage of simple structure, can adapt to the interval of the noise elimination frequency from high frequency to low frequency by changing the length of the side branch pipe, and is a classic silencer structure. However, after the length of the side branch pipe is determined, the silencing frequency of the classical quarter-wave pipe silencer is fixed, and the silencing frequency of the quarter-wave pipe silencer is narrow-band silencing, namely the silencing frequency is narrow, so that only the target frequency can be attenuated, and broadband silencing cannot be performed.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a variable cross section silencer to solve the technical problem that the broadband noise elimination can not be carried out to the quarter wave pipe that exists among the prior art.
In order to achieve the above object, the utility model adopts the following technical scheme: the variable cross-section silencer comprises a first cut-off frequency surface, a second cut-off frequency surface, a front wall, a rear wall and a transition surface, wherein the first cut-off frequency surface and the second cut-off frequency surface are oppositely arranged, the front wall and the rear wall are oppositely arranged, two sides of the transition surface are respectively connected to the first cut-off frequency surface and the second cut-off frequency surface, the other two sides of the transition surface are respectively connected to the front wall and the rear wall, the length of the first cut-off frequency surface is smaller than that of the second cut-off frequency surface, the first cut-off frequency surface, the second cut-off frequency surface, the front wall, the rear wall and the transition surface are enclosed to form a trapezoidal cavity with a sound wave inlet, and the transition.
In one embodiment, the first cut-off frequency surface and the second cut-off frequency surface are arranged oppositely on one side in the length direction and staggered on the other side in the length direction, so that the silencer is in a right-angled trapezoid shape, and the transition surface is obliquely arranged.
In one embodiment, the first cut-off frequency surface is a flat surface, a semi-circular arc surface, or a polygonal surface.
In one embodiment, the transition surface is a flat surface, a wavy surface, or a stepped surface.
In one embodiment, the front wall and the rear wall are both flat and parallel to each other; alternatively, the first and second electrodes may be,
the front wall and the rear wall are wavy surfaces or a plurality of semi-circular arc surfaces which are connected in sequence, and the tangent surfaces of the front wall and the rear wall are parallel to each other.
In one embodiment, the diameters of the semicircular arc surfaces of the front wall and the rear wall are the same as the width of the first cut-off frequency surface and the width of the second cut-off frequency surface.
In one embodiment, the first cut-off frequency surface has a length h1The length of the second cut-off frequency plane is h2Maximum upper cut-off frequency of the silencer is
The minimum lower cut-off frequency of the silencer is
Where c is the speed of sound.
In one embodiment, the first cut-off frequency surface and the second cut-off frequency surface both have a width d, and the distance between the first cut-off frequency surface and the second cut-off frequency surface is L, L>1.5h2And L is>3d。
In one embodiment, the sound transmission loss of the variable cross-section muffler
Wherein m is
The ratio of the cross-sectional area of the main pipe,
the utility model provides a variable cross section silencer's beneficial effect lies in: compared with the prior art, the utility model discloses variable cross section silencer is trapezoidal setting, including relative first cut-off frequency face and the second cut-off frequency face that sets up, relative antetheca and the back wall and the transition face that sets up, the transition face is just being provided with the sound wave entry. Because the lengths of the first cut-off frequency surface and the second cut-off frequency surface are different, the section of the variable-section silencer from the first cut-off frequency surface to the second cut-off frequency surface is changed constantly, which is equivalent to a silencer with a plurality of quarter-wave tubes with different lengths, therefore, the broadband silencing can be realized, and the air flow can not be influenced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments or the prior art descriptions will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive labor.
Fig. 1 is a first variable cross-section muffler provided by an embodiment of the present invention;
fig. 2 is a second variable cross-section muffler provided by the embodiment of the present invention;
fig. 3 is a third variable cross-section muffler provided by the embodiment of the present invention;
fig. 4 is a fourth variable cross-section muffler provided by the embodiment of the present invention;
fig. 5 is an evolution schematic diagram of an embodiment of the present invention;
fig. 6 is a graph comparing the actual sound transmission loss curve of the variable cross-section muffler and the quarter-wave tube provided by the embodiment of the present invention.
Wherein, in the figures, the respective reference numerals:
100-quarter wave tube; 1-a variable cross-section muffler; 11a, 11b, 11c — a first cut-off frequency plane; 12a, 12b, 12 c-a second cut-off frequency plane; 13-front wall; 14-rear wall; 15a, 15 b-transition surfaces; 16-sonic inlet.
Detailed Description
In order to make the technical problem, technical solution and advantageous effects to be solved by the present invention more clearly understood, the following description is given in conjunction with the accompanying drawings and embodiments to illustrate the present invention in further detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.
The embodiment of the present invention provides a variable cross section muffler 1.
The first embodiment is as follows:
referring to fig. 1, in a first embodiment of the variable cross-section muffler, the variable cross-section muffler includes a first cut-off frequency surface 11a and a second cut-off frequency surface 12a which are oppositely arranged, a front wall 13 and a rear wall 14 which are oppositely arranged, and a transition surface 15a which is composed of five surfaces. The five surfaces are enclosed to form a trapezoidal cavity muffler, and it should be noted that, each surface of the trapezoidal cavity muffler is not necessarily a plane, as long as the combined shape is approximately trapezoidal. One surface of the trapezoid cavity silencer is in an open shape and is a sound wave inlet 16, the sound wave inlet 16 is opposite to the transition surface 15a, and the sound wave inlet 16 can be connected with a main pipe generating airflow noise. The length of the first cut-off frequency surface 11a is smaller than that of the second cut-off frequency surface 12a, so that the length of the section of the silencer from the first cut-off frequency surface 11a to the second cut-off frequency surface 12a is changed constantly, namely the variable section of the variable section silencer is changed, and the silencer can correspondingly correspond to silencing of different frequencies, and therefore broadband silencing is achieved. More specifically, according to the principle of the anti-muffler, the noise reduction frequency of the anti-muffler is related to the length of the anti-muffler, when the length of the anti-muffler is fixed, sound waves with specific frequency enter the anti-muffler, the sound waves are continuously reflected in the anti-muffler, the phase of the sound waves is opposite to that of incident sound waves, and the incident sound waves and the reflected sound waves are mutually counteracted to form a sound pressure node or reduce the amplitude of the incident sound waves, so that the purpose of sound reduction is achieved. The length of the variable cross-section silencer in the inflow direction of the air flow is gradually changed, so that the variable cross-section silencer can correspondingly reduce noise in a wider frequency band, the purpose of broadband noise reduction is achieved, and the air flow cannot be disturbed.
In the variable cross-section muffler of the above embodiment, since the lengths of the first cut-off frequency surface 11a and the second cut-off frequency surface 12a are different, the cross section of the variable cross-section muffler from the first cut-off frequency surface 11a to the second cut-off frequency surface 12a is changed continuously, which corresponds to the provision of the plurality of quarter wave tubes 100 having different lengths, so that the sound can be attenuated in a wide frequency band without affecting the flow of the gas.
Referring to fig. 1, in this embodiment, the first cut-off frequency surface 11a and the second cut-off frequency surface 12a are disposed opposite to each other on one side in the length direction and are disposed in a staggered manner on the other side in the length direction, so that the muffler is a rectangular trapezoid muffler, wherein the transition surface 15a is disposed in an inclined manner. And the opposite sides of the first cut-off frequency plane 11a and the second cut-off frequency plane 12a are both the sound wave inlet 16 side. In this way, when the variable cross-section muffler is connected as a bypass pipe to a main pipe to be muffled, the first cut-off frequency surface 11a and the second cut-off frequency surface 12a are both connected perpendicular to the main pipe, and the noise of the gas flow in the main pipe can be further muffled.
More specifically, referring to fig. 1, the first cut-off frequency plane 11a and the second cut-off frequency plane 12a are parallel to each other and are both planar, the front wall 13 and the rear wall 14 are parallel to each other and are both planar, and the transition plane 15a is also planar. The variable cross-section silencer in the embodiment has a simple structure and is convenient to process and manufacture.
Example two:
referring to fig. 2, in the second embodiment of the variable cross section muffler, the difference from the first embodiment is: the first cut-off frequency surface 11b and the second cut-off frequency surface 12b are both semicircular arc surfaces. In this embodiment, the diameter of the semicircular arc surface may be equal to the width d of the first cut-off frequency surface 11b and the second cut-off frequency surface 12b, so that the upper and lower sides of the variable cross-section muffler are closer to the shape (i.e., arc surface) of the wave tube 100, and the sound attenuation effect is better. In other embodiments, one of the first cut-off frequency surface and the second cut-off frequency surface is a semicircular arc surface, and the other of the first cut-off frequency surface and the second cut-off frequency surface is a flat surface or a polytropic surface.
Example three:
referring to fig. 3, in a third embodiment of the variable cross-section muffler, the difference from the first embodiment is: the first cutoff frequency plane 11c and the second cutoff frequency plane 12c are both polygonal planes. In other embodiments, one of the first cut-off frequency surface and the second cut-off frequency surface is a polygonal surface, and the other of the first cut-off frequency surface and the second cut-off frequency surface is a flat surface or a semicircular arc surface. Of course, in other embodiments, the first cut-off frequency plane and the second cut-off frequency plane may also be triangular planes, wavy planes, etc., and the specific shape is not limited.
Example four:
referring to fig. 4, in a fourth embodiment of the variable cross-section muffler, the difference from the first embodiment is: the transition surface 15b is a wavy surface, and the wavy direction of the wavy surface may be from the first cut-off frequency surface 11a to the second cut-off frequency surface 12a, or from the front wall 13 to the rear wall 14. In other embodiments, the transition surface may also be a curved surface, a multi-variable surface, a triangular surface, a step shape, or the like.
Example five:
in the fourth embodiment of the variable cross-section muffler, the difference from the first embodiment is that: the front wall and the rear wall are wavy surfaces or a plurality of semi-circular arc surfaces connected in sequence, and the wavy direction of the wavy surfaces can be from the first cut-off frequency surface 11a to the second cut-off frequency surface 12a or from the sound wave inlet 16 to the transition surface 15 a. The circumscribed surfaces of the front and rear walls are parallel to each other. In other embodiments, the front wall 13 and the rear wall 14 may also have a curved surface, a polygonal surface, a triangular surface, a step shape, and the like.
Further, in the fifth embodiment, the diameters of the semicircular arc surfaces of the front wall 13 and the rear wall 14 are the same as the width of the first cutoff frequency surface 11a and the width of the second cutoff frequency surface 12 a. In this embodiment, the shape of the variable cross-section muffler is closer to the shape formed by radially stacking a plurality of quarter wave tubes 100, the muffling performance is better, and the flow of the gas stream is not affected as the quarter wave tubes 100 are stacked.
Referring to fig. 5, fig. 5 is a schematic diagram illustrating the evolution of the quarter-wave tube 100 into the variable-section muffler 1 of the present embodiment. The single quarter-wave tube 100 is a pipe type silencer, and has the characteristics of wide frequency adaptability, simple structure, narrow-band silencing and the like, but in practical industrial application, the operation of machine equipment is changed under most conditions, and along with the change of operation conditions, the main noise frequency band changes, and the silencer designed aiming at one operation condition originally and possibly cannot be applied to another operation condition. In the leftmost diagram of fig. 5, in the model formed by stacking a plurality of quarter-wave tubes 100, the lengths of the quarter-wave tubes 100 are sequentially changed, so that noises with various frequencies can be eliminated, and broadband noise elimination is realized. However, the overlapping structure of the wave tubes 100 is dense, so that the flow of the airflow is greatly disturbed, and the noise of the airflow is not eliminated. In the middle schematic diagram of fig. 5, a trapezoid structure is formed according to the shape of the plurality of stacked quarter-wave tubes 100, and the trapezoid structure is similar to the stacked quarter-wave tubes 100 in shape. In the final schematic diagram of fig. 3, the wall of each wave tube 100 is eliminated to form the variable cross-section muffler 1. The variable cross-section silencer 1 is simple in structure, can be applied to a broadband silencing application scene of pneumatic noise, and has a better broadband silencing effect compared with a silencer with a single quarter-wave tube 100.
In any of the above embodiments of the variable cross-section muffler, the first cut-off frequency surface has a length h1The second cut-off frequency plane has a length h2，h1The size of the variable cross-section silencer determines the upper silencing cut-off frequency h of the variable cross-section silencer2The size of the variable cross-section muffler determines the muffling lower cut-off frequency of the variable cross-section muffler. More specifically, the maximum upper cut-off frequency of the muffler is
The minimum lower cut-off frequency of the silencer is
Where c is the speed of sound. Corresponding h can be set according to the requirement of the user on the noise elimination frequency band1And h2。
The widths of the first cut-off frequency surface and the second cut-off frequency surface are both d, the size of d is equivalent to the diameter of a side branch pipe in the formula of the noise elimination distance of the quarter-wave pipe 100, and the distance between the first cut-off frequency surface and the second cut-off frequency surface is L, namely the width of the variable cross-section muffler is L. L is>1.5h2And L is>3d, the variable cross-section silencer is equivalent to at least 5 quarter wave tubes 100, so that the variable cross-section silencer can have a wider silencing frequency and a better silencing effect. L is>3d, the variable cross-section muffler can be equivalent to a quarter wave tube 100 with an infinite number of continuous and different cavity depths.
In addition, when the variable cross section muffler in the present embodiment is used, the sound transmission loss with respect to the start noise of a certain frequency
Wherein m is the ratio of the circular cross-sectional area of the wave-length tube with d as the diameter to the main tube cross-sectional area, i.e.
The ratio of the cross-sectional area of the main pipe,
referring to fig. 6, fig. 6 is a comparison graph of the actual sound transmission loss curves of the variable cross-section muffler 1 and the quarter wave pipe 100, the solid line is the sound transmission loss curve of the muffler of the quarter wave pipe 100, and the dotted line is the sound transmission loss curve of the variable cross-section muffler 1. In the graph of fig. 6, the abscissa represents frequency, and the ordinate represents sound transmission loss. From the comparison of the sound transmission loss of the solid line and the dotted line, it is obvious that the frequency band that the variable cross-section muffler 1 can attenuate is wider, and the frequency band that the quarter-wave tube 100 can attenuate is narrower. More specifically, the variable cross section muffler 1 used in fig. 6 has the following specific parameters: h is1＝26mm，h229mm, 19mm and 5mm, and the target noise elimination frequency is 3150 Hz; the quarter wave tube 100 used in fig. 6 has the following specific parameters: the diameter of the side branch pipe is 5mm, the length of the side branch pipe is 26mm, and the target noise elimination frequency is 3150 Hz.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. Variable cross section silencer, its characterized in that: the silencer comprises a first cut-off frequency surface, a second cut-off frequency surface, a front wall, a rear wall and a transition surface, wherein the first cut-off frequency surface and the second cut-off frequency surface are oppositely arranged, the front wall and the rear wall are oppositely arranged, two sides of the transition surface are respectively connected to the first cut-off frequency surface and the second cut-off frequency surface, the other two sides of the transition surface are respectively connected to the front wall and the rear wall, the length of the first cut-off frequency surface is smaller than that of the second cut-off frequency surface, the first cut-off frequency surface, the second cut-off frequency surface, the front wall, the rear wall and the transition surface are enclosed to form a trapezoidal cavity silencer with a sound wave inlet.
2. The variable cross-section muffler of claim 1, wherein: the first cut-off frequency surface and the second cut-off frequency surface are arranged on one side in the length direction in a right-angle opposite mode, and are arranged on the other side in the length direction in a staggered mode, so that the silencer is in a right-angle trapezoid shape, and the transition surface is arranged in an inclined mode.
3. The variable cross-section muffler of claim 2, wherein: the first cut-off frequency surface is a straight surface, a semi-circular arc surface or a polygonal surface.
4. The variable cross-section muffler of claim 2, wherein: the transition surface is a flat surface, a wavy surface or a stepped surface.
5. The variable cross-section muffler of claim 2, wherein: the front wall and the rear wall are flat surfaces and are parallel to each other; alternatively, the first and second electrodes may be,
the front wall and the rear wall are wavy surfaces or a plurality of semi-circular arc surfaces which are connected in sequence, and the tangent surfaces of the front wall and the rear wall are parallel to each other.
6. The variable cross-section muffler of claim 5, wherein: the diameters of the semi-circular arc surfaces of the front wall and the rear wall are the same as the width of the first cut-off frequency surface and the width of the second cut-off frequency surface.
7. The variable cross-section muffler of claim 1, wherein: the first cut-off frequency surface has a length h1The length of the second cut-off frequency plane is h2Maximum upper cut-off frequency of the silencer is
The minimum lower cut-off frequency of the silencer is
Where c is the speed of sound.
8. The variable cross-section muffler of claim 7, wherein: said first cut-off frequency plane and saidThe width of the second cut-off frequency surface is d, and the distance between the first cut-off frequency surface and the second cut-off frequency surface is L, L>1.5h2And L is>3d。
9. The variable cross-section muffler of claim 8, wherein: sound transmission loss of the variable cross-section muffler
Wherein m is
The ratio of the cross-sectional area of the main pipe,
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922374799.1U CN211667379U (en) | 2019-12-25 | 2019-12-25 | Variable cross-section silencer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922374799.1U CN211667379U (en) | 2019-12-25 | 2019-12-25 | Variable cross-section silencer |
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| Publication Number | Publication Date |
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| CN211667379U true CN211667379U (en) | 2020-10-13 |
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| CN201922374799.1U Active CN211667379U (en) | 2019-12-25 | 2019-12-25 | Variable cross-section silencer |
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