CN1573199A - Noise reduction structure of porous plate - Google Patents
Noise reduction structure of porous plate Download PDFInfo
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- CN1573199A CN1573199A CNA200410047512XA CN200410047512A CN1573199A CN 1573199 A CN1573199 A CN 1573199A CN A200410047512X A CNA200410047512X A CN A200410047512XA CN 200410047512 A CN200410047512 A CN 200410047512A CN 1573199 A CN1573199 A CN 1573199A
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- 230000009467 reduction Effects 0.000 title abstract description 19
- 238000005192 partition Methods 0.000 claims abstract description 15
- 230000003584 silencer Effects 0.000 claims description 62
- 238000010276 construction Methods 0.000 claims description 57
- 238000011144 upstream manufacturing Methods 0.000 claims description 9
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 30
- 239000000463 material Substances 0.000 description 18
- 238000013016 damping Methods 0.000 description 12
- 238000002474 experimental method Methods 0.000 description 10
- 230000010355 oscillation Effects 0.000 description 9
- 230000009471 action Effects 0.000 description 7
- 230000010349 pulsation Effects 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 239000011491 glass wool Substances 0.000 description 5
- 230000004888 barrier function Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- 239000010883 coal ash Substances 0.000 description 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
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- 230000021715 photosynthesis, light harvesting Effects 0.000 description 1
- 230000029058 respiratory gaseous exchange Effects 0.000 description 1
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- 239000002699 waste material Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N1/00—Silencing apparatus characterised by method of silencing
- F01N1/02—Silencing apparatus characterised by method of silencing by using resonance
- F01N1/023—Helmholtz resonators
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust Silencers (AREA)
- Pipe Accessories (AREA)
- Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
Provided is a small noise reduction structure capable of exhibiting full noise reduction performance over a wide frequency bandwidth. The noise reduction structure D comprises a cylindrical duct 41; a perforated panel 42 extended inside the duct 41 along the axial direction of the duct 41 and positioned to define the duct cross section of the duct 41; and partition panels 43 by which the duct 41 defined by the perforated panel 42 is axially partitioned into a plurality of cells 44. The intervals at which the partition panels 43 are installed are adjusted so that b<c/(4f) where f is the maximum frequency of noises to be reduced; c is the sound velocity of a medium; and b is the interval at which the partition panels 43 are installed. The aperture ratio of the perforated panel 42 is 1 to 10%.
Description
Technical field
The present invention relates to the technology of giving the silencer construction in the pipe arrangement road that gas or exhaust use between device or device.
Background technique
In the prior art, the technology of silencer construction is known.For example, disclosed technology in non-patent literature 1 and patent documentation 2 is arranged.In this non-patent literature 1, hush pipe A shown in Figure 1 and resonance silencer B shown in Figure 2 etc. are disclosed.Hush pipe A shown in Figure 1 is that tetragonal pipe 11 and porous matter quieter material 12 constitute by the cross section.This silencer construction is: porous matter quieter material 12 (for example, glass wool or steel fiber etc.) disposes with certain thickness along managing 11 inwalls in pipe 11, by this porous matter quieter material 12 acoustic energy that dissipates.Resonance silencer B shown in Figure 2 is made of the amplification chamber 24 that pipe arrangement road 21 and encirclement are opened in the aperture 23 on the pipe arrangement road 21.Resonance silencer B to by pipe arrangement road 22 by f
p=(c/2 π) √ { s
p/ (Vm
p) the noise of the frequency determined of calculating formula carry out the selectivity noise reduction.At this, f
pBe the highest frequency of desiring to abate the noise, c is the velocity of sound of medium, s
pBe hole diameter, V is for amplifying chamber volume, m
pBe little hole depth.
The soundproof tectosome C of porous matter shown in Figure 3 is disclosed in patent documentation 2.The soundproof tectosome C of porous matter shown in Figure 3 will adorn plate 31 outward and dispose opposed to each other with the interior dress plate 32 with a plurality of through hole 32a.Thickness of slab, aperture and the opening rate of dress plate 32 make it satisfy the design condition that produces viscous effect on the air of circulation through hole 32a in setting, by the energy of its viscous effect dissipation sound wave.
[non-patent literature 1] Japanese mechanology can be compiled " mechanicalness noise handbook industry books
[patent documentation 2] spy opens the 2003-50586 communique
But, in the formation of the hush pipe A of above-mentioned non-patent literature 1, there is following problem: owing to the change in flow on pipe arrangement road, temperature variation, dewfall etc. cause variation all the year round of porous matter quieter material itself or deterioration to be dispersed, not only performance muffler descends, and enter the device of compressor, turbo machine, pump etc., thereby the performance of these devices is significantly descended or it is broken down.In addition, when discarding hush pipe, because the porous matter quieter material of glass wool etc. becomes trade waste, so can produce the expense of separating and handling.In addition, in the formation of the resonance silencer B of above-mentioned non-patent literature 1, there is following problem: owing to can only eliminate the noise of assigned frequency, so in order in big frequency range, to obtain erasure effect, must connect a plurality of resonance silencers that are adjusted to different frequency, in addition, need surround the amplification chamber of pipe arrangement road aperture in pipe arrangement road arranged outside, overall volume is bigger.And then, in the formation of the soundproof tectosome C of porous matter of above-mentioned patent documentation 2, there is following problem: usually, the more little performance muffler of opening is high more, if but in compressor etc., use, then because opening is little, it is big that the possibility of coal ash, rubbish, oil droplet, drop occlusion of openings becomes, thereby make performance muffler reduce.
Summary of the invention
The problem that the present invention will solve the following describes the method and the effect thereof that are used to solve this problem as mentioned above.
Promptly, in the present invention, silencer construction have the pipe arrangement road, along the axle direction on pipe arrangement road extend first partition member that is provided with, the axle direction on the pipe arrangement road that will be divided by first partition member is divided into second partition member of a plurality of cells, forming a plurality of holes on all or part of of the part of stream one side of first partition member.
According to this formation, since have the pipe arrangement road, along the axle direction on pipe arrangement road extend first partition member that is provided with, the axle direction on the pipe arrangement road that will be divided by first partition member is divided into second partition member of a plurality of cells, on all or part of of the part of stream one side of first partition member, forming a plurality of holes, so do not influence the proper flow on pipe arrangement road, and the pressure oscillation in cycle is transformed to the to-and-fro motion of the hole portion of porous slab, thereby can abate the noise with the form dissipation pressure oscillation energy of the pressure loss.In addition, in the present embodiment, owing to have silencer construction in inside, pipe arrangement road, so need not at the unnecessary device of pipe arrangement road outer installment etc., so equipment can not maximize.And then, owing to do not use for example porous matter quieter material of glass wool, so there is not following problem: by variation all the year round or deterioration and cause dispersing of porous matter quieter material itself, thereby performance muffler is descended, perhaps this porous matter quieter material that has dispersed enters devices such as compressor, turbo machine, pump, thereby the performance of these devices is significantly descended or it is broken down.In addition, also have the expense that does not produce porous matter quieter material itself or be used to protect the advantage of expense of the surface protecting material etc. of this porous matter quieter material, and use porous matter quieter material to compare to suppress manufacture cost.
When silencer construction of the present invention is respectively f, c, b at the interval of the velocity of sound of the highest frequency of the noise that makes desire eliminate, medium, dividing plate, satisfy the relation of b＜c/ (4f).
According to this formation, because when being respectively f, c, b at the interval of the velocity of sound of the highest frequency of the noise that makes desire eliminate, medium, dividing plate, satisfy the relation of b＜c/ (4f), so do not influence the proper flow on pipe arrangement road, and the pressure oscillation in cycle is transformed to reliably the to-and-fro motion of the hole portion of porous slab, thereby can abate the noise with the form dissipation pressure oscillation energy of the pressure loss.
The opening rate of porous slab of the present invention is 1～10%.Thus, be 1～10% owing to make the opening rate of porous slab, so even also can bring into play high erasure effect in the zone that reaches 130～180dB.
In the present invention, the opening rate of porous slab reduces downstream gradually from the upstream of stream.According to this formation, by reducing opening rate gradually, accelerate the air vibration speed of the porous portion under the acoustic pressure of downstream one side step-down, can be suitable for the value of sound-absorbing most, can improve performance muffler.
Description of drawings
Fig. 1 is the figure of the hush pipe of expression prior art.
Fig. 2 is the figure of the resonance silencer of expression prior art.
Fig. 3 is the figure of the soundproof tectosome of porous matter of expression prior art.
Fig. 4 is the figure of expression first mode of execution of the present invention.
Fig. 5 is the figure of expression second mode of execution of the present invention.
Fig. 6 is the figure of expression the 3rd mode of execution of the present invention.
Fig. 7 is the figure that is used to verify the noise reduction theory of porous slab.
The frequency analysis result's of the pressure oscillation of the discharge pipe arrangement way outlet portion when Fig. 8 is condition 1 in the expression experiment 1 and condition 3 figure.
Fig. 9 is the figure of the experimental result in the expression experiment 3.
Figure 10 is the figure of the variation of expression the 3rd mode of execution of the present invention.
Figure 11 is the figure of the experimental result in the expression experiment 4.
Figure 12 is the otch side view of the variation of expression the 3rd mode of execution of the present invention.
Figure 13 is the sectional view of expression the 4th mode of execution of the present invention.
Figure 14 is the sectional view of the variation of expression the 4th mode of execution of the present invention.
Figure 15 is the sectional view of expression the 5th mode of execution of the present invention.
Embodiment
Below, the working of an invention mode is described.Fig. 4 is the figure of expression first mode of execution of the present invention.The silencer construction D of Fig. 4 has the pipe arrangement road 41 of tubular, in the inside on pipe arrangement road 41 along the axle direction on pipe arrangement road 41 extend ground, cross section, the pipe arrangement road configuration that is provided with and divides pipe arrangement road 41 porous slab 42, will be divided into the dividing plate 43 of a plurality of cells 44 by the axle direction of pipe arrangement road 41 that porous slab 42 is separated on the pipe arrangement road.
The following describes the action of the sound wave in the pipe arrangement road 41 of present embodiment.Sound wave is by primary flow path 45, and the hole portion 46 by porous slab 42 injects in the cell 44 then, in cell 44 internal reflections and logical once more via portion 46.The incident of this sound wave and reflection are carried out in each cell 44 repeatedly via the hole portion 46 of porous slab 42.
According to present embodiment, do not influence the proper flow on pipe arrangement road, and the pressure oscillation in cycle is transformed to the to-and-fro motion of the hole portion of porous slab, can be with the form dissipation pressure oscillation energy of the pressure loss, thus can abate the noise.Especially, be 1～10% owing to make the opening rate of porous slab, so reaching the bigger erasure effect of zone performance of 130～180dB.In addition, in the present embodiment, owing to have silencer construction in inside, pipe arrangement road, so need not at the unnecessary device of pipe arrangement road outer installment etc., so equipment can not maximize.
And then, in the present embodiment, owing to do not use for example porous matter quieter material of glass wool, so there is not following problem: by variation all the year round or deterioration and cause dispersing of porous matter quieter material itself, thereby performance muffler is descended, perhaps this porous matter quieter material that has dispersed enters devices such as compressor, turbo machine, pump, thereby the performance of these devices is significantly descended or it is broken down.And then, have the expense that does not produce porous matter quieter material itself or be used to protect the advantage of expense of the surface protecting material etc. of this porous matter quieter material, can suppress manufacture cost.
In addition, the porous slab 42 in the above-mentioned mode of execution be provided with the position can for, for example when desiring to make primary flow path 45 broads near pipe arrangement road 41 inwalls, if do not consider the width of primary flow path 45 then also can be the arbitrary position.In addition, in the above-described embodiment, porous slab 42 is set in parallel in the pipe arrangement road on pipe arrangement road 41, but when not considering the width of primary flow path 45, not necessarily it will be set in parallel in the pipe arrangement road on pipe arrangement road 41, the arbitrarily angled setting of can tilting.This point also is same in the following embodiments.
Fig. 5 is the figure of expression second mode of execution of the present invention.The silencer construction E of Fig. 5 is the center with the axle on pipe arrangement road 41, be provided with in 41 inside, pipe arrangement road with a side of cell 44 symmetries of the silencer construction D of above-mentioned first mode of execution a plurality of same cells 44 '.That is, the silencer construction E of present embodiment by above-mentioned silencer construction D, in the inside on pipe arrangement road 41 along the axle direction on pipe arrangement road 41 extend the porous slab 42 that is provided with and separates ground, cross section, the pipe arrangement road configuration on pipe arrangement road 41 ' and will be divided into by the axle direction on the pipe arrangement road on the pipe arrangement road 41 of porous slab 42 ' divided a plurality of cells 44 ' dividing plate 43 ' constitute.
In addition, porous slab 42, dividing plate 43 and cell 44 are identical with the silencer construction D of above-mentioned first mode of execution.
The following describes the action of the sound wave in the pipe arrangement road 41 of present embodiment.Sound wave is by primary flow path 55, then by porous slab 42,42 ' hole portion separately 46,46 ' inject cell 44,44 ' in, cell 44,44 ' internal reflection and logical once more via portion 46,46 '.The incident of this sound wave and reflection via porous slab 42,42 ' hole portion 46,46 ' and separately each cell 44,44 ' in carry out repeatedly.
Can obtain the effect same by present embodiment with first mode of execution.
In addition, as modified embodiment of the present embodiment, can be make porous slab 42,42 ' the structure that reduces downstream and gradually from the upstream of stream 55 of opening rate.Specifically, porous slab 42,42 ' opening rate towards each cell 44,44 ' each zone respectively different, towards the downstream, opening rate diminishes gradually along with gradually.For example, making the opening rate towards the porous slab zone of the cell of upstream one side that is formed at stream 55 is 8%.In addition, making the opening rate towards the porous slab zone of the cell of adjacency downstream one side is 5%.Below, similarly carry out repeatedly, make along with one side towards the downstream gradually the structure that the opening rate of each cell diminishes gradually.
Porous slab 42,42 ' hole portion 46,46 ' in gas vibration velocity by be applied to hole portion 46,46 ' the acoustic pressure and the opening rate of sound wave determined.In stream 55 because the acoustic pressure of upstream one side is higher than the acoustic pressure of downstream one side, so the porous slab 42,42 by reducing downstream one side ' opening rate, can increase logical via portion 46,46 ' the vibration velocity of gas, can improve performance muffler.This o'clock is all identical in first mode of execution or following mode of execution.In addition, also can for opening rate with towards cell 44,44 ' the irrelevant structure that diminishes gradually in zone.
Fig. 6 is the figure of expression the 3rd mode of execution of the present invention.The silencer construction F of Fig. 6 has: pipe arrangement road 41, separation are provided with a plurality of annular baffle 63 in the inside on pipe arrangement road 41 along the porous tube 62 in 41 cross sections, pipe arrangement road of the axle direction extension setting on pipe arrangement road 41 with in the mode that the space between porous tube outer wall 62 and pipe arrangement road 41 inwalls is separated along the axle direction on pipe arrangement road 41.
The following describes the making method of the silencer construction F of present embodiment.At first, form porous tube 62, the inboard of the dividing plate 63 of ring-type is welded on this porous tube 62 outsides thereby on tube, offer the hole.Make on one side the b that is spaced apart of the dividing plate 63 that adjoins each other, reach required number Yi Bian carry out repeatedly.In addition, be welded on the inboard on pipe arrangement road 41, finish silencer construction F by the outside with each dividing plate 63.In addition, thereby also can be 41 form it into porous tube, make at its outside other outer tubes of configuration from offering the hole on one's body on the pipe arrangement road.
The following describes the action of the sound wave in the pipe arrangement road 41 of present embodiment.Sound wave is by primary flow path 65, and each hole portion 66 by porous tube 62 injects in the cell 64 then, in cell 64 internal reflections and logical once more via portion 66.The incident of this sound wave and reflection are carried out in each cell 64 separately repeatedly via the hole portion 66 of porous tube 62.
Can obtain the effect same by present embodiment with first mode of execution.
In addition, in the silencer construction of above-mentioned first, second mode of execution, only be provided with a porous slab, but its silencer construction also can and then be provided with an above porous slab, the dividing plate of required number as one man is set therewith, by so form cell, be not inferior to the erasure effect of the silencer construction of above-mentioned first, second mode of execution.In addition, in the silencer construction of above-mentioned the 3rd mode of execution, only be provided with a porous tube, but its silencer construction also can and then be provided with a porous tube that above radius is different, the dividing plate of required number as one man is set therewith, by so form cell, be not inferior to the erasure effect of the silencer construction of above-mentioned the 3rd mode of execution.And then, also can be for having made up the silencer construction of above-mentioned first to the 3rd mode of execution.For example, pack into simultaneously in the pipe arrangement road porous tube and porous slab are formed the silencer construction of cell etc. by many dividing plates.
Figure 10 is the figure of the variation of expression the 3rd mode of execution.Omit the explanation of the part identical with the 3rd mode of execution.As shown in figure 10, the pipe arrangement road of the silencer construction F1 of the variation of the 3rd mode of execution is the pipe arrangement road 41a that narrows down steppedly, and this point is different with the silencer construction F of the 3rd mode of execution.Specifically, pipe arrangement road 41a forms a plurality of onesize cell 64a in the upstream of primary flow path 65 side, and one side forms the length (highly) of cross-wise direction on a plurality of pipe arrangements road less than the cell 64b of cell 64a in the downstream.By increasing cell, can increase the noise reduction rate of low range, so narrow down steppedly, the noise reduction scope is broadened by the cell that makes silencer construction F1.
In addition, as shown in figure 12, also the pipe arrangement road 41 that can narrow down gradually for the pipe arrangement road ' structure.Because the pipe arrangement road 41 by making silencer construction F2 ' narrow down gradually, change the resonant frequency of each cell 64 of separating, so can be corresponding to the noise source of in a big way frequency.In addition, the effect of these variation is owing to same with the 3rd mode of execution, so also can obtain and the 3rd
The effect that mode of execution is same.
In addition, though not shown, in first, second mode of execution, too, narrow down by making the pipe arrangement road steppedly, or it is narrowed down gradually, have the effect same with above-mentioned variation.Each following mode of execution and variation are too.
Figure 13 is the axial sectional view of pipe arrangement of expression the 4th mode of execution.Omit and the same explanation partly of the respective embodiments described above.As shown in figure 13, silencer construction H have pipe arrangement road 41, in the inside on pipe arrangement road 41 along the axle direction on pipe arrangement road 41 extend be provided with and the cross section be divided into fan-shaped porous tube 62 ', with the axle direction of porous tube 62 ' inside be divided into the dividing plate 102 of a plurality of cells 104 and fixed bearing porous tube 62 ' support unit 101.
Porous tube 62 ' be divided into 8 fan-shaped cartridges by a plurality of dividing plates 102 for the cross section similarly disposes with the axle direction on pipe arrangement road 41 abreast with the 3rd mode of execution.By this configuration, the porous tube 62 ' cross section on pipe arrangement road 41 is divided into by the space of gas and the space by gas not.Porous tube 62 ' a plurality of holes opening, the opening rate in hole is preferably 1～10%.This porous tube 62 ' be fixedly attached to pipe arrangement road 41 by support unit 101.This support unit 101 can be made bar-shaped, only is installed in for fixed bearing porous tube 62 ' desired position, also can make tabular fix supporting cellular tube 62 '.
Cell 104 surrounds by porous tube 62 ' inwall, adjacent 2 aforementioned barriers 102 with the adjacent not shown aforementioned barriers of interval b and forms.
The following describes the action of the sound wave in the pipe arrangement road 41 of present embodiment.Sound wave is by primary flow path 105, then by porous tube 62 ' each hole portion 66 inject in the cell 104, in cell 104 internal reflections and logical once more via portion 66.The incident of this sound wave and the reflection via porous tube 62 ' hole portion 66 and in each cell 104 separately, carry out repeatedly.
Can obtain the effect same by present embodiment with first mode of execution.
In addition, represented in the present embodiment 8 fan-shaped mode of executions of porous tube 62 ' be divided into, but be not limited thereto, as long as be divided into a plurality of fan-shaped effects same that just have with present embodiment.In addition, each fan-shaped also can be unequal.
Figure 14 is the figure of the variation of expression the 4th mode of execution.Omit the explanation of the part identical with the 4th mode of execution.As shown in figure 14, silencer construction H1 has the cell 114,115 that varies in size, and this point is different with the silencer construction G of the 4th mode of execution.
Cell 114, as shown in figure 14, by porous tube 62 ' inwall, separate the dividing plate 113 of ground, porous tube 62 ' cross section configuration, the dividing plate 112 that vertically dispose with this dividing plate 113 and separation surround with the axial not shown dividing plate of the adjacent porous tube 62 of interval b ' inside and form.
Cell 115, as shown in figure 14, by porous tube 62 ' inwall, separate the dividing plate 113 of ground, porous tube 62 ' cross section configuration, the dividing plate 111 and 112 that vertically dispose with this dividing plate 113, separation surround with the axial not shown dividing plate of the adjacent porous tube 62 of interval b ' inside and form.
The following describes the action of the sound wave in the pipe arrangement road 41 of present embodiment.Sound wave is by primary flow path 105, then by porous tube 62 ' each hole portion 66 inject in the cell 114,115, in cell 114,115 internal reflections and logical once more via portion 66.The incident of this sound wave and the reflection via porous tube 62 ' hole portion 66 and in each cell 114,115 separately, carry out repeatedly.
Can obtain the effect same by present embodiment with the 4th mode of execution.In addition, because the resonant frequency difference of each cell, so can be corresponding to the noise source of different frequency.
In addition, cell constitutes as described above in the present embodiment, if thereby but by so setting and dividing plate 111,112 parallel dividing plates form cell, then owing to the resonant frequency difference of these cells, and then can be corresponding to the noise source of different frequency.
Figure 15 is the axial sectional view of pipe arrangement of expression the 5th mode of execution.Omit and the same explanation partly of the respective embodiments described above.As shown in figure 15, silencer construction I has: pipe arrangement road 41, extend along the axle direction on pipe arrangement road 41 in the inside on pipe arrangement road 41 and to be provided with and the cross section is quadrilateral, has only the porose porous tube 121 of one side, the axle direction of porous tube 121 inside is divided into the not shown dividing plate of a plurality of cells 124.
Porous tube 121, its cross section is a quadrilateral, has the porous slab 122 of only having offered a plurality of holes on the one side of primary flow path 125 sides.In addition, for example, the bight 123 in these many holes 121 is waited by welding and is installed on pipe arrangement road 41, thus fixing porous tube 121.
The following describes the action of the sound wave in the pipe arrangement road 41 of present embodiment.Sound wave is by primary flow path 125, and each hole portion 126 by porous tube 121 injects in the cell 124 then, in cell 124 internal reflections and logical once more via portion 126.The incident of this sound wave and reflection are carried out in each cell 124 repeatedly via the hole portion 126 of porous tube 121.
Can obtain the effect same by present embodiment with first mode of execution.
In addition, only disposed 1 porous tube 121 in the present embodiment, but disposing a plurality of these porous tubes 121 also can obtain effect same.In addition,, make their resonant frequency difference, so can be corresponding to the noise source of different frequency by disposing the porous tube 121 that a plurality of sectional areas vary in size.
In addition, the pipe arrangement road is a cylinder in the respective embodiments described above or each variation, waits other different shapes also to have same above-mentioned effect but cross section, pipe arrangement road is polygonals such as four limits or ellipse.In addition, also the porous slab of the respective embodiments described above or each variation axle direction with respect to the pipe arrangement road can be disposed obliquely, or stepped configuration.By such configuration, thus since change the resonant frequency of each separation space can be corresponding to the noise source of in a big way frequency.And then the respective embodiments described above and each variation preferably are provided with flange etc. at least one end on these pipe arrangement roads, by bolt etc. its mounting or dismounting are installed on other pipe arrangement roads that are provided with the flange that becomes the noise reduction object etc. freely.
(checking 1)
Verify for noise reduction condition b＜c/ of the present invention (4f).For example in first mode of execution of Fig. 4, sound wave enters cell 44 from primary flow path 45 logical via portion 46, by the pipe arrangement road 41 inwalls reflection in the cell 44, along the logical via portion 46 of opposite direction.At this moment, in hole portion 46 pressure loss takes place.If but the longer dimension of cell 44, then sound wave advances to the long direction of size, the reflected wave minimizing to hole portion 46.That is, be equivalent in the overall dimensions of cell 44 produce the resonance phenomenon of cell 44 under 1/2 the frequency of wave length of sound, sound wave is only advanced repeatedly in cell 44 and is reflected, and disappears to the reflected wave of hole portion 46.Therefore, in order to limit the unexpected action of sound wave in such cell 44, if adjust dividing plate 43 the highest frequency that makes at interval at the noise that makes desire eliminate is set is f, the velocity of sound of medium is c, dividing plate 43 be spaced apart b the time, satisfy b＜c/ (4f) and get final product.In second, third mode of execution too.
(checking 2)
Below, verify about the opening rate of the porous slab among the present invention and the relation of erasure effect.The dynamic pressure loss for the viscosity in the boundary layer that is formed at the silencer construction surface and the alternating flow that stream dwindles portion can roughly be distinguished by acoustic energy dissipation mechanism during noise reduction.Under the sound pressure level in the daily life space, vibration amplitude is small, loses and compares and can ignore with the viscosity that the first power of speed is directly proportional with the dynamic pressure that velocity squared is directly proportional.Therefore, in general silencer construction, viscosity long-pending with enlarged surface and the increase boundary layer is problem, thereby becomes the shape of fibrous (glass wool etc.) or film shape (urethane etc.).But on the discharge pipe arrangement road as compressor, the pressure pulsation level arrives under the situation of 130～180dB, can not ignore the dynamic pressure loss.Therefore, from having considered the noise reduction theory of the porous slab that viscosity and dynamic pressure are lost, verify for the opening rate of the porous slab in the present embodiment and the relation of erasure effect.
Fig. 7 is the sectional view of silencer construction G.Silencer construction G is made of tube 71 and porous slab 72.Internally be provided with a porous slab 72 in the inside of tube 71 along longitudinal direction separating tube 71.
Use Fig. 7 that the noise reduction theory of porous slab is described.The formula of the noise reduction theory of porous slab is with following formula (1) expression, by formula (1) derivation formula (2).
At this, p
1Be the acoustic pressure on porous slab 72 left sides, p
2Be the acoustic pressure on porous slab 72 right sides, U
1Be the volume velocity on porous slab 72 left sides, U
2Be the volume velocity on porous slab 72 right sides, Γ is the characteristic of porous portion, and ρ is the density of air, and c is the velocity of sound, the sectional area of S for being responsible for, and k is a wave number.
Z with above-mentioned formula (2)
1Substitution is at Im[Z
1]=0, Re[Z
1]=Re[Γ]=noise reduction rate maximum during ρ c/S.Wherein, the characteristic Γ of porous portion represents with following formula.
At this, t is the thickness of slab of porous slab, and d is the pore diameter of porous slab, and ρ is the density of air, and μ is moving coefficient of viscosity, and ω is an angular frequency, and A is the gross area of pore, ζ
0Be pressure drop coefficient, U
2Volume velocity for porous slab 72 right sides.
In theory, at Re[Γ]=noise reduction rate maximum during ρ c/S.For with its rationalization, the real part of Γ multiply by area S, relatively the value of first (viscosity term) and second (dynamic pressure item).Wherein, the typical value of each constant is used following value.t＝1mm，μ＝1.8E-5，f＝1kHz，ρ＝1.2kg/m
3，c＝340m/s，ζ
0＝2.6，d＝2mm，|U
2|＝S|u
2|，p＝ρc?u
2，u
2＝2×10
-5×10
(L/20)。
Calculating is satisfied the opening rate of following formula and is organized in the table 1 under each sound pressure level L under two conditions on normal temperature atmosphere and helical-lobe compressor discharge pipe arrangement road.Wherein, in order to be the zone of several %, make pressure drop coefficient adopt definite value, ζ at opening rate
0=2.6.
[table 1]
| ? c＝ ρ＝ | 340m/s 1.2kg/m in the normal temperature atmosphere 3 | 376m/s 7.8kg/m in the compressor 3 |
| ????SPL ????[dB] | Optimum opening porosity Re[S* Γ] the 1st [%] the 2nd [%] A/S[%] (viscosity term) (dynamic pressure item) | Optimum opening porosity Re[S* Γ] the 1st [%] the 2nd [%] A/S[%] (viscosity term) (dynamic pressure item) |
| ????180 ????170 ????160 ????150 ????140 ????130 ????120 ????110 | ????40.0????408????1?????99 ????22.6????408????2?????98 ????12.8????408????3?????97 ????7.3?????408????5?????95 ????4.2?????408????9?????91 ????2.4?????408????16????84 ????1.5?????408????26????74 ????0.9?????408????41????59 | ????14.20????2970????1??????99 ????8.00?????2970????2??????98 ????4.50?????2970????3??????97 ????2.57?????2970????5??????95 ????1.48?????2970????9??????91 ????0.87?????2970????16?????84 ????0.52?????2970????26?????74 ????0.33?????2970????42?????58 |
As shown in Table 1, under two conditions all be, sound pressure level is viscosity term and dynamic pressure item balance when 110dB, and the ratio of dynamic pressure item is 74% when 120dB.Therefore, under two conditions, can think to be top dog when sound pressure level dynamic pressure item when 120dB is above.The opening rate of this moment is 1.5%.The maximum sound pressure of observing in the atmosphere, about the air breathing engine outlet was for 150dB, opening rate was about 7.3%.Thus, preferably using opening rate in order to have surplus capacity is 1～10% porous slab.Pulsation voltage levels in the discharge pipe arrangement road of compressor is 130～180dB, is appreciated that also to wish that the use opening rate is 1～10% porous slab this moment.
(experiment 1)
Use has the discharge pipe arrangement road with the helical-lobe compressor of the same silencer construction of first mode of execution, carries out the experiment of erasure effect.Discharge in the pipe arrangement road at this, in following three conditions: 1. not only use porous slab but also use dividing plate, 2. do not use dividing plate, only use porous slab, 3. neither use porous slab also not use dividing plate, measure the pressure pulsation of these silencer construction front and back down, and its pressure pulsation difference is represented in table 2 as sound-damping qualities.
[table 2]
| Octave frequency band | Condition 1 | Condition 2 | Condition 3 |
| ??250Hz | 169-161＝8dB | 170-165＝5dB | 169-170＝-1dB |
| ??500Hz | 170-154＝16dB | 170-162＝8dB | 170-170＝0dB |
| ??1kHz | 173-150＝23dB | 172-164＝8dB | 173-173＝0dB |
| ??2kHz | 168-143＝25dB | 168-161＝7dB | 168-169＝-1dB |
| ??4kHz | 161-143＝18dB | 160-153＝7dB | 161-160＝1dB |
Sound press=the sound-damping qualities at the sound pressure level of the front side of baffler-baffler rear
According to table 2, the sound-damping qualities of condition 1 is obviously bigger, and is special, the high frequency of disturbing others 1, can obtain the sound-damping qualities of 25dB under the octave frequency band of 2kHz.In addition, also can obtain significant sound-damping qualities 2 times in condition, but owing to there is not dividing plate, so pressure oscillation, forms the pressure difference inside and outside the porous slab in porous slab whole spatial diffusion behind unlike theoretical institute is said, pressure pulsation fully decays.Condition 3 is simple pipe arrangement roads, does not have the noise reduction ability certainly.
The frequency analysis result's of the pressure oscillation of the discharge pipe arrangement way outlet portion when in addition, Fig. 8 is above-mentioned condition 1 of expression and condition 3 figure.
According to Fig. 8, compare with the situation on the discharge pipe arrangement road of the condition 3 of not using any, used the discharge pipe arrangement road of condition 1 of the present invention obviously to have erasure effect in broadband range.
Thus, can confirm that by above-mentioned experimental result the silencer construction of first mode of execution of the present invention has sufficient erasure effect in broadband range.
(experiment 2)
Use has the discharge pipe arrangement road with the helical-lobe compressor of the same silencer construction of second mode of execution, carries out the experiment of erasure effect.Discharge in pipe arrangement road at this, the rotating speed of helical-lobe compressor is set at 3000 respectively to be changeed and 4000 changes, and measures the pressure pulsation of these silencer construction front and back, and its pressure pulsation difference is represented in table 3 as sound-damping qualities.
[table 3]
| ??????????3000rpm | ?????????????4000rpm | |||||||
| 1 250Hz | 2 500Hz | 3 750Hz | 4 1000Hz | 1 333Hz | 2 666Hz | 3 999Hz | 4 1333Hz | |
| Reduction amount behind the baffler before the baffler | ?161dB ?148dB ?13dB | ??165dB ??148dB ??17dB | ?166dB ?150dB ?16dB | ?176dB ?159dB ?17dB | ?170dB ?158dB ?12dB | ?162dB ?146dB ?16dB | ?182dB ?164dB ?16dB | ?174dB ?162dB ?22dB |
As shown in Table 3, the rotating speed of helical-lobe compressor be 3000 change and arbitrary situations of 4000 commentaries on classics under, all on average bring into play high erasure effect in broadband range.Thus, the silencer construction that can confirm second mode of execution of the present invention has sufficient erasure effect in broadband range.
(experiment 3)
Employing has the discharge pipe arrangement road of the helical-lobe compressor of second mode of execution, carries out the experiment of erasure effect under two kinds of situations certain and that reduce gradually downstream from the upstream of stream as the opening rate of the variation of second mode of execution at the opening rate of porous slab.In addition, in Fig. 5, mutual opposed cell 44,44 ' size is identical.The certain silencer construction of opening rate experimentizes under following parameter: the length on axial pipe arrangement road is 1.2m, and the length of the cell of cross-wise direction (highly) is 10mm, and opening rate is 5%.In addition, in the length 1.2m on pipe arrangement road, comprise 4 cells.In addition, the height and the quantity of the length on its pipe arrangement road of silencer construction of changing of opening rate, cell are identical.In addition, the opening rate towards the zone of the porous slab of cell begins to be followed successively by 8%, 8%, 5%, 3% from the cell that is positioned at the stream upstream, experimentizes under this parameter.
Fig. 9 is the chart with respect to the sound-damping qualities of the frequency of sound wave under the certain situation of opening rate of expression silencer construction and the situation about reducing gradually.At this, sound-damping qualities is for the volume (unit is ' dB ') from upstream one side of stream deducts the numerical value of the volume of downstream one side, and it is big more to be worth big more representative erasure effect.Can be confirmed that by Fig. 9 compare with the situation that opening rate is certain, the sound-damping qualities of the silencer construction that opening rate reduces gradually is bigger, that is, erasure effect is bigger.
(experiment 4)
In the silencer construction F1 of silencer construction F identical with the 3rd mode of execution and variation shown in Figure 10, the sound-damping qualities of noise more separately experimentizes.Experimentize under following parameter: the opening rate of porous tube 62 is 5%, the height of the cell 64 of silencer construction F is 10mm, and the length on axial pipe arrangement road is 1.2m, and the height of the cell 64a of silencer construction F1 is 10mm, the height of cell 64b is 5mm, and the length on pipe arrangement road is 1.2m.In the length 1.2m on pipe arrangement road, all comprise 4 cells,, respectively comprise two cell 64a64b respectively about silencer construction F1.Figure 11 is the figure of expression with respect to the sound-damping qualities of frequency of sound wave.Can be confirmed that by figure under the situation of frequency greater than 2500Hz of sound wave, the sound-damping qualities of the silencer construction F1 of cell ladder variation is bigger, frequency range that can noise reduction is wideer.
Claims (4)
1. silencer construction, it is characterized by: have the pipe arrangement road, along the axle direction on above-mentioned pipe arrangement road extend first partition member that is provided with, the axle direction on the above-mentioned pipe arrangement road that will be divided by above-mentioned first partition member is divided into second partition member of a plurality of cells, is being formed with a plurality of holes on all or part of of the part of stream one side of above-mentioned first partition member.
2. silencer construction as claimed in claim 1 is characterized by: when being respectively f, c, b at the interval of the velocity of sound of the highest frequency of the noise that makes desire eliminate, medium, dividing plate, satisfy the relation of b＜c/ (4f).
3. silencer construction as claimed in claim 1 or 2 is characterized by: the opening rate of above-mentioned porous slab is 1-10%.
4. as each described silencer construction of claim 1 to 3, it is characterized by: the opening rate of above-mentioned porous slab reduces towards the downstream gradually from the upstream of above-mentioned stream.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP146579/2003 | 2003-05-23 | ||
| JP146579/03 | 2003-05-23 | ||
| JP2003146579 | 2003-05-23 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1573199A true CN1573199A (en) | 2005-02-02 |
| CN1311186C CN1311186C (en) | 2007-04-18 |
Family
ID=32588733
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200410047512XA Expired - Lifetime CN1311186C (en) | 2003-05-23 | 2004-05-21 | Noise reduction structure of porous plate |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN1311186C (en) |
| SE (1) | SE525807C2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102996302A (en) * | 2012-08-11 | 2013-03-27 | 郭荣 | Silencer capable of eliminating both wideband noises and narrowband noises |
| TWI392838B (en) * | 2010-06-10 | 2013-04-11 | Univ Nat Taiwan Normal | Whistle box structure |
| CN107850091A (en) * | 2016-02-22 | 2018-03-27 | 三菱重工业株式会社 | Lower noise constructs and supercharging device |
| CN108266590A (en) * | 2016-12-30 | 2018-07-10 | 艾默生过程管理调节技术公司 | For the noise muffler being used together with process control equipment |
| CN114127459A (en) * | 2019-07-22 | 2022-03-01 | 株式会社电装 | Sound absorbing device |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2093003U (en) * | 1991-05-10 | 1992-01-15 | 刘余厚 | Liquid ultraviolet treatment device |
| JP3026694B2 (en) * | 1993-04-19 | 2000-03-27 | 河西工業株式会社 | Soundproofing materials for vehicles |
| JPH0849521A (en) * | 1994-08-08 | 1996-02-20 | Hino Motors Ltd | Muffler |
| CN2407133Y (en) * | 2000-01-25 | 2000-11-22 | 中国科学院声学研究所 | Tubular perforated plate sound absorption construction |
| CN2494914Y (en) * | 2000-09-15 | 2002-06-12 | 上海众汇泡沫铝材有限公司 | Foam aluminium sheet type noise absorber |
| CN2444295Y (en) * | 2000-09-20 | 2001-08-22 | 上海博旭复合装饰材料有限公司 | Combined sound absorption board |
| JP2003050586A (en) * | 2000-09-29 | 2003-02-21 | Kobe Steel Ltd | Porous soundproof structure and method of manufacturing the same |
-
2004
- 2004-05-21 CN CNB200410047512XA patent/CN1311186C/en not_active Expired - Lifetime
- 2004-05-24 SE SE0401313A patent/SE525807C2/en not_active IP Right Cessation
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI392838B (en) * | 2010-06-10 | 2013-04-11 | Univ Nat Taiwan Normal | Whistle box structure |
| CN102996302A (en) * | 2012-08-11 | 2013-03-27 | 郭荣 | Silencer capable of eliminating both wideband noises and narrowband noises |
| CN107850091A (en) * | 2016-02-22 | 2018-03-27 | 三菱重工业株式会社 | Lower noise constructs and supercharging device |
| CN108266590A (en) * | 2016-12-30 | 2018-07-10 | 艾默生过程管理调节技术公司 | For the noise muffler being used together with process control equipment |
| CN114127459A (en) * | 2019-07-22 | 2022-03-01 | 株式会社电装 | Sound absorbing device |
Also Published As
| Publication number | Publication date |
|---|---|
| SE0401313L (en) | 2004-11-24 |
| SE525807C2 (en) | 2005-05-03 |
| CN1311186C (en) | 2007-04-18 |
| SE0401313D0 (en) | 2004-05-24 |
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Effective date of registration: 20220322 Address after: Kobe City, Hyogo Prefecture, Japan Patentee after: Kobe Steel, Ltd. Patentee after: Shengang Compressor Co.,Ltd. Address before: Japan Hyogo Prefecture Patentee before: Kobe Steel, Ltd. |
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Granted publication date: 20070418 |