JP2012180792A - Muffler - Google Patents

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JP2012180792A
JP2012180792A JP2011044596A JP2011044596A JP2012180792A JP 2012180792 A JP2012180792 A JP 2012180792A JP 2011044596 A JP2011044596 A JP 2011044596A JP 2011044596 A JP2011044596 A JP 2011044596A JP 2012180792 A JP2012180792 A JP 2012180792A
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silencer
absorbing layer
sound absorbing
sound
partition plate
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Keita Okuyama
圭太 奥山
Shiro Takahashi
志郎 高橋
Akinori Tamura
明紀 田村
Teppei Kubota
哲平 久保田
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Hitachi GE Nuclear Energy Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a muffler capable of reducing noise even if the Mach number of steam is large without using a fibrillar sound-deadening material.SOLUTION: The muffler includes: a porous plate-shaped inner cylinder; an outer cylinder disposed to face the inner cylinder with a predetermined gap; a sound absorbing layer composed of a space formed of the inner cylinder and the outer cylinder; and a partition plate for axially dividing the space of the sound absorbing layer into a plurality of sections. The porous plate is formed of a porous plate.

Description

本発明は消音器に係り、特に、原子力発電所や火力発電所等の高温高圧環境における騒音対策として好適な消音器に関する。   The present invention relates to a silencer, and more particularly to a silencer suitable as a noise countermeasure in a high temperature and high pressure environment such as a nuclear power plant or a thermal power plant.

通常、原子力発電所や火力発電所等では、タービンで発電機を駆動して発電を行うために、タービン前後の配管に高温高圧の蒸気を流すが、この配管に備えられている分岐部やオリフィス部において騒音が発生することがある。   Normally, in a nuclear power plant or a thermal power plant, in order to generate electricity by driving a generator with a turbine, high-temperature and high-pressure steam flows through piping before and after the turbine. Noise may occur in the section.

このような場合は、周囲への環境を配慮して消音器を設置することで、あるレベル以下となるように音の強さを変えて騒音を低下させている。   In such a case, by installing a silencer in consideration of the environment to the surroundings, the sound intensity is changed so as to be below a certain level to reduce noise.

一般的な消音器の構成を、図2及び図3に示す。該図に示す如く、消音器5は、多孔板形状の内筒4と、この内筒4と所定間隔をもって対向配置された外筒2と、内筒4と外筒2により構成される空間から成る吸音層3と、この吸音層3の空間を複数に細分化する仕切板1と、細分化された各吸音層3内のそれぞれに設置された繊維系の消音材7とから概略構成され、配管6と内筒4とは、両者のフランジ部分がボルト等により締結されている。   The structure of a general silencer is shown in FIGS. As shown in the figure, the silencer 5 includes a perforated plate-shaped inner cylinder 4, an outer cylinder 2 arranged to face the inner cylinder 4 at a predetermined interval, and a space formed by the inner cylinder 4 and the outer cylinder 2. A sound absorbing layer 3, a partition plate 1 for subdividing the space of the sound absorbing layer 3 into a plurality of pieces, and a fiber-based sound deadening material 7 installed in each of the subdivided sound absorbing layers 3, The pipe 6 and the inner cylinder 4 are fastened to each other by bolts or the like.

そして、消音器5に蒸気と共に騒音が配管6を介して流れ込むと、消音器5においては、蒸気は多孔板形状の内筒4の内側を通過するが、騒音である音波の一部は、内筒4と同心円で内筒4の外側に設置されている吸音層3に入り込む。吸音層3は、内筒4と外筒2により構成される空間であり、吸音層3の空間が大きい場合は、吸音層3の内部において大小様々な波長の音波が発生しやすくなり、騒音を消す目的で設置した消音器5から新たに騒音が生じることがある。   When noise flows into the silencer 5 along with the steam through the pipe 6, the steam passes through the inner side of the perforated plate-shaped inner cylinder 4 in the silencer 5. It enters the sound absorbing layer 3 that is concentric with the cylinder 4 and is installed outside the inner cylinder 4. The sound absorbing layer 3 is a space composed of the inner cylinder 4 and the outer cylinder 2, and when the space of the sound absorbing layer 3 is large, sound waves of various wavelengths are easily generated inside the sound absorbing layer 3, and noise is generated. A new noise may be generated from the silencer 5 installed for the purpose of extinguishing.

これを防ぐため、吸音層3は、仕切板1により空間が軸方向(蒸気の流れ方向)に細分化されると共に、細分化された各吸音層3内には、繊維系の消音材7が設置されている。   In order to prevent this, the sound absorbing layer 3 is subdivided in the axial direction (steam flow direction) by the partition plate 1, and in each of the subdivided sound absorbing layers 3, a fiber-based silencer 7 is provided. is set up.

騒音である音波には、多孔板形状である内筒4を通過する際に、多孔板の孔部において摩擦損失が生じるため、音波のエネルギーが失われ、騒音が小さくなる。更に、吸音層3に入った音波は、繊維系の消音材7を通過する際にも同様に繊維材との間に摩擦損失が生じエネルギーを失い、騒音が低くなる。以上により、消音器5から排出される蒸気に含まれる騒音が低下する。   When the sound wave, which is noise, passes through the inner cylinder 4 having a perforated plate shape, friction loss occurs in the hole of the perforated plate, so that the energy of the sound wave is lost and the noise is reduced. Further, when the sound wave entering the sound absorbing layer 3 passes through the fiber silencer 7, friction loss is similarly generated between the fiber material and energy is lost, and noise is reduced. As a result, the noise contained in the steam discharged from the silencer 5 is reduced.

繊維系の吸音材7としては、一般にグラスウールやロックウール、ステンレスウールなどが用いられる。グラスウールやロックウールについては、高温、高圧の環境下において劣化することが懸念されている。また、ステンレスウールについては、上記2種類の消音材7と比べると耐熱性は高いが、一般にこれらの消音材7の線径は多孔板4の孔径よりも小さいため、やはり吸音層3から脱離し飛散することが懸念されている。   As the fiber-based sound absorbing material 7, glass wool, rock wool, stainless wool or the like is generally used. Regarding glass wool and rock wool, there is concern that they will deteriorate under high temperature and high pressure environments. Stainless steel wool has higher heat resistance than the above two types of sound deadening material 7, but generally the wire diameter of these sound deadening materials 7 is smaller than the hole diameter of the perforated plate 4. There are concerns about the scattering.

このように、繊維系の消音材7には、劣化による飛散のリスクがあるため、繊維系の消音材7を用いない消音器が提案されてきた。   As described above, since the fiber silencer 7 has a risk of scattering due to deterioration, a silencer that does not use the fiber silencer 7 has been proposed.

例えば、特許文献1では、消音したい音波の波長に合わせてステンレス焼結金網と孔なしの仕切板により構成されている吸音層の寸法を調節することで、繊維系の消音材を用いることなく、騒音となる音波の音圧を低減する方法を開示している。   For example, in Patent Document 1, by adjusting the size of the sound absorbing layer formed of a stainless steel wire mesh and a partition plate without holes in accordance with the wavelength of the sound wave to be silenced, without using a fiber-based silencer, A method of reducing the sound pressure of a sound wave that becomes noise is disclosed.

また、非特許文献1では、多孔板と孔なし仕切板により構成されている吸音層の寸法を調整することで、吸音層のヘルムホルツ共鳴周波数を調節し、ヘルムホルツ共鳴周波数に近い騒音は、吸音層においてエネルギーが吸収されることから、騒音となる音波の音圧を低減することができるとしている。尚、非特許文献1でも、繊維系の消音材は用いていない。   Further, in Non-Patent Document 1, by adjusting the size of the sound absorbing layer constituted by the porous plate and the partition plate without holes, the Helmholtz resonance frequency of the sound absorbing layer is adjusted, and noise close to the Helmholtz resonance frequency is Since the energy is absorbed in, the sound pressure of the sound wave that becomes noise can be reduced. Note that even in Non-Patent Document 1, a fiber-based silencer is not used.

特開平8−210119号公報JP-A-8-210119

木村康正、他1名、ターボ機械の静音化 スクリュー圧縮機の低騒音化事例、ターボ機械第35巻第10号、(2007)Yasumasa Kimura, 1 other, Silencer of turbomachinery Example of noise reduction of screw compressor, Turbomachinery Vol.35 No.10, (2007)

しかしながら、特許文献1及び非特許文献1においても、消音器5に流れるマッハ数が大きい。即ち、蒸気の流速が速い場合、内筒4である多孔板において、新たな騒音が発生することが本発明者らの研究で明らかになった。ここで、マッハ数とは、流れの圧縮性を特徴付ける無次元数で、消音器5に流れ込む流体の平均流速を流体の音速で除した値である。   However, also in Patent Document 1 and Non-Patent Document 1, the Mach number flowing through the silencer 5 is large. That is, it has been clarified by the present inventors that new noise is generated in the perforated plate that is the inner cylinder 4 when the flow velocity of the steam is high. Here, the Mach number is a dimensionless number characterizing the compressibility of the flow, and is a value obtained by dividing the average flow velocity of the fluid flowing into the silencer 5 by the sound velocity of the fluid.

内筒4である多孔板で発生する騒音の原理を、図4を用いて説明する。消音器5に蒸気が流れると、多孔板である内筒4の孔部から音波が発生する。この段階において音圧は非常に低く、騒音として問題にはならない。これが吸音層3を伝播し、外筒2で反射した後、内筒4に戻る。この戻ってきた音波と、内筒4で新たに発生する音波の位相が合うと、新たに発生する音波の音圧が強くなる。   The principle of noise generated in the perforated plate that is the inner cylinder 4 will be described with reference to FIG. When steam flows through the silencer 5, sound waves are generated from holes in the inner cylinder 4 that is a perforated plate. At this stage, the sound pressure is very low and does not matter as noise. This propagates through the sound absorbing layer 3 and is reflected by the outer cylinder 2, and then returns to the inner cylinder 4. When the returned sound wave and the newly generated sound wave in the inner cylinder 4 are in phase, the sound pressure of the newly generated sound wave is increased.

以上の過程が繰り返されることで、騒音として問題になるまで音波が非常に強くなる。仕切板を密に配置することで、吸音層3で発生する騒音の波長を小さくすることができるが、騒音の発生自体を抑制することは困難である。   By repeating the above process, the sound wave becomes very strong until it becomes a problem as noise. By arranging the partition plates densely, the wavelength of noise generated in the sound absorbing layer 3 can be reduced, but it is difficult to suppress the generation of noise itself.

従って、蒸気のマッハ数が大きい場合において、繊維系の消音材を使うことなく、騒音を低下させる消音器が望まれていた。   Accordingly, there has been a demand for a silencer that reduces noise without using a fiber-based silencer when the Mach number of steam is large.

本発明は上述の点に鑑みなされたもので、その目的とするところは、蒸気のマッハ数が大きい場合においても、繊維系の消音材を使うことなく騒音を低下させることができる消音器を提供することにある。   The present invention has been made in view of the above points, and an object thereof is to provide a silencer that can reduce noise without using a fiber-based silencer even when the Mach number of steam is large. There is to do.

本発明の消音器は、上記目的を達成するために、多孔板形状の内筒と、該内筒と所定間隔をもって対向配置された外筒と、前記内筒と外筒により構成される空間から成る吸音層と、該吸音層の空間を軸方向に複数に細分化する仕切板とを備えた消音器において、前記仕切板が、多孔板で形成されていることを特徴とする。   In order to achieve the above object, the silencer of the present invention comprises a perforated plate-shaped inner cylinder, an outer cylinder disposed to face the inner cylinder at a predetermined interval, and a space formed by the inner cylinder and the outer cylinder. A silencer comprising a sound absorbing layer and a partition plate that subdivides the space of the sound absorption layer into a plurality of portions in the axial direction is characterized in that the partition plate is formed of a porous plate.

本発明の消音器によれば、蒸気のマッハ数が大きい場合においても、繊維系の消音材を使うことなく騒音を低下させることができる。   According to the silencer of the present invention, it is possible to reduce noise without using a fiber-based silencer even when the Mach number of steam is large.

本発明の消音器の実施例1を示す水平断面図である。It is a horizontal sectional view showing Example 1 of a silencer of the present invention. 一般的な消音器を示す水平断面図である。It is a horizontal sectional view showing a general silencer. 図2に示した消音器のA−A’線に沿う断面図である。It is sectional drawing which follows the A-A 'line of the silencer shown in FIG. 一般的な内筒を形成する多孔板で発生する音波の発生原理を説明するための図である。It is a figure for demonstrating the generation principle of the sound wave which generate | occur | produces with the perforated plate which forms a general inner cylinder. 本発明の消音器の実施例1により吸音層に騒音が発生しない原理をするための図である。It is a figure for carrying out the principle which noise does not generate | occur | produce in a sound absorption layer by Example 1 of the silencer of this invention. 本発明の実施例1に示す消音器と、吸音層に孔なしの仕切板を用いた消音器の騒音特性を示す図である。It is a figure which shows the noise characteristic of the silencer which shows the silencer shown in Example 1 of this invention, and the partition plate without a hole in a sound absorption layer. 本発明の消音器の実施例2を示す水平断面図である。It is a horizontal sectional view showing Example 2 of a silencer of the present invention. 本発明の消音器の実施例3を示す水平断面図である。It is a horizontal sectional view showing Example 3 of a silencer of the present invention. 本発明の消音器を火力プラントに適用した例を示す図である。It is a figure which shows the example which applied the silencer of this invention to the thermal power plant. 本発明の消音器を原子力プラントに適用した例を示す図である。It is a figure which shows the example which applied the silencer of this invention to the nuclear power plant. 本発明の消音器を空気圧縮機に適用した例を示す図である。It is a figure which shows the example which applied the silencer of this invention to the air compressor.

以下、図示した実施例に基づいて、本発明の消音器を説明する。尚、符号は、従来と同一のものは同符号を使用する。   The silencer of the present invention will be described below based on the illustrated embodiment. Note that the same reference numerals are used for the same reference numerals.

図1は、本発明の消音器5の実施例1を示すものである。一般的な消音器5として説明した図2及び図3との相違点は、吸音層3の空間を軸方向に複数に仕切っている(細分化している)仕切板8を、多孔板形状に形成したことである。他の構成は、図2及び図3に示した一般的な消音器5と同様である。   FIG. 1 shows a first embodiment of a silencer 5 of the present invention. 2 and FIG. 3 described as a general silencer 5 is that the partition plate 8 that partitions the space of the sound absorbing layer 3 into a plurality of pieces (subdivided) in the axial direction is formed in a perforated plate shape. It is that. Other configurations are the same as those of the general silencer 5 shown in FIGS. 2 and 3.

本実施例においては、多孔板形状の仕切板8は、その孔径やピッチ、開口率(孔の面積/仕切板の面積)がすべて同じ形状である。また、複数枚ある多孔板形状の仕切板8は、軸方向に同じ間隔(距離)で配置されている。   In the present embodiment, the porous plate-shaped partition plate 8 has the same shape in terms of its hole diameter, pitch, and aperture ratio (hole area / partition plate area). The plurality of perforated plate-shaped partition plates 8 are arranged at the same interval (distance) in the axial direction.

そして、騒音を含む蒸気は、配管6を介して消音器5に流入して多孔板形状の内筒4の内部を通過するが、騒音である音波の一部は、内筒4と同心円で内筒4の外側に設置されている吸音層3に入り込む。この吸音層3に入り込む音波は、内筒4の多孔板の孔部を通過する際に摩擦損失によりエネルギーを失う。   The steam containing noise flows into the silencer 5 through the pipe 6 and passes through the inside of the perforated plate-shaped inner cylinder 4, but a part of the sound wave that is noise is concentric with the inner cylinder 4. It enters the sound absorbing layer 3 installed outside the cylinder 4. The sound wave entering the sound absorbing layer 3 loses energy due to frictional loss when passing through the hole of the perforated plate of the inner cylinder 4.

また、(数1)に示すヘルムホルツ周波数(fr)と音波(騒音)の周波数が一致する場合は、吸音層3内の仕切られた空間の蒸気がヘルムホルツ共鳴器として働き、音波のエネルギーの一部が共鳴器内の蒸気の振動エネルギーとして使われるため、音圧が低下する。 When the Helmholtz frequency (f r ) shown in (Equation 1) and the sound wave (noise) frequency match, the vapor in the partitioned space in the sound absorbing layer 3 functions as a Helmholtz resonator, Since the part is used as vibration energy of the vapor in the resonator, the sound pressure decreases.

Figure 2012180792
Figure 2012180792

ここで、cは音速(m/s)、πは円周率、Nは内筒4の孔の数、Vは吸音層3の総体積(m)、Gは多孔板形状の仕切板8の孔1個の伝導度で(数2)のようになる。 Here, c is the speed of sound (m / s), π is the circularity ratio, N is the number of holes in the inner cylinder 4, V is the total volume (m 3 ) of the sound absorbing layer 3, and G is a porous plate-shaped partition plate 8 The conductivity of one hole is expressed as (Equation 2).

Figure 2012180792
Figure 2012180792

ここで、sは多孔板形状の仕切板8の孔1個の面積(m)、rは多孔板形状の仕切板8の厚さ(m)、dは多孔板形状の仕切板8の孔径(m)である。 Here, s is the area (m 2 ) of one hole of the porous plate-shaped partition plate 8, r is the thickness (m) of the porous plate-shaped partition plate 8, and d is the hole diameter of the porous plate-shaped partition plate 8. (m).

上記したように、本実施例では、吸音層3が多孔板形状の仕切板8により軸方向に複数仕切られている。この構成の消音器5に蒸気を流すと、多孔板形状である内筒4では音波が発生するが、吸音層3が多孔板形状の仕切板8により軸方向に仕切られているため、外筒2の内壁で反射した音波のエネルギーが、多孔板形状の仕切板8を介して隣の吸音層3に拡散する。   As described above, in this embodiment, the sound absorbing layer 3 is partitioned in the axial direction by the partition plate 8 having a perforated plate shape. When steam is passed through the silencer 5 having this configuration, sound waves are generated in the inner cylinder 4 having a perforated plate shape, but the sound absorbing layer 3 is partitioned in the axial direction by a partition plate 8 having a perforated plate shape. The energy of the sound wave reflected by the inner wall 2 diffuses to the adjacent sound absorbing layer 3 through the partition plate 8 having a perforated plate shape.

吸音層3の空間が完全に仕切られないことから、吸音層3の内部には大小様々な波長の音波が発生する可能性が生じるが、これらの音波が多孔板形状の仕切板8の孔部を通過する際に摩擦損失を受けるため、吸音層3の内部に発生する音圧は低くなり、騒音として問題にはならない。   Since the space of the sound absorbing layer 3 is not completely partitioned, there is a possibility that sound waves of various wavelengths may be generated inside the sound absorbing layer 3, and these sound waves are generated in the holes of the porous plate-shaped partition plate 8. The sound pressure generated in the sound absorbing layer 3 is low because it receives a friction loss when passing through, and does not cause a problem as noise.

次に、本実施例における効果を、図5を用いて説明する。   Next, the effect in a present Example is demonstrated using FIG.

本実施例によれば、消音器5に蒸気を流すと多孔板形状である内筒4では音波が発生するが、従来とは異なり、吸音層3が多孔板形状の仕切板8により軸方向に仕切られているため、音波のエネルギーが外筒2で反射する際に、多孔板形状の仕切板8を介して隣の吸音層3にエネルギーが発散する。これにより、上述したような音圧を強くする繰り返し過程が生じにくくなるため、騒音が低下する。   According to the present embodiment, when steam is passed through the silencer 5, sound waves are generated in the perforated inner tube 4, but unlike the prior art, the sound absorbing layer 3 is axially formed by the perforated plate-shaped partition plate 8. Due to the partitioning, when sound wave energy is reflected by the outer cylinder 2, the energy is diffused to the adjacent sound absorbing layer 3 through the porous plate-shaped partition plate 8. As a result, it becomes difficult to generate a repeating process for increasing the sound pressure as described above, and noise is reduced.

仕切板8を多孔板形状としたことにより、吸音層3の空間が完全に仕切られていない。これにより吸音層3の内部には、大小様々な波長の音波が発生する可能性が生じるが、これらの音波が、多孔板形状の仕切板8の孔部を通過する際に摩擦損失を受けるため、吸音層3の内部に発生する音圧は低くなり、騒音として問題にはならない。   Since the partition plate 8 has a perforated plate shape, the space of the sound absorbing layer 3 is not completely partitioned. As a result, there is a possibility that sound waves of various wavelengths may be generated inside the sound absorbing layer 3, but these sound waves are subjected to friction loss when passing through the holes of the porous plate-shaped partition plate 8. The sound pressure generated inside the sound absorbing layer 3 becomes low and does not cause a problem as noise.

尚、多孔板形状の仕切板8として複数種類の多孔板を用いたり、仕切板8を等間隔に限定せずに、様々なピッチで配置したりすることで、更に騒音低減効果が向上する。   In addition, the noise reduction effect is further improved by using a plurality of types of perforated plates as the perforated plate-shaped partition plate 8 or arranging the partition plates 8 at various pitches without being limited to equal intervals.

本実施例の消音器5に空気を送風した際の騒音特性を図6に示す。図6は横軸に周波数を、縦軸に音圧を取り、従来の孔なし板を仕切板として用いた場合(A)と、本実施例の多孔板形状の仕切板を用いた場合(B)を比較したものである。   FIG. 6 shows noise characteristics when air is blown to the silencer 5 of this embodiment. In FIG. 6, the horizontal axis represents frequency, the vertical axis represents sound pressure, and a conventional holeless plate is used as the partition plate (A), and the porous plate-shaped partition plate of this embodiment is used (B ).

該図から明らかな如く、従来の(A)では、消音器から強い音波が発生しているが、本実施例の(b)では、音波が発生していないことがわかる。   As is apparent from the figure, in the conventional (A), a strong sound wave is generated from the silencer, but in the present embodiment (b), it can be seen that no sound wave is generated.

これにより、本実施例では、蒸気のマッハ数が大きい場合においても、繊維系の消音材を使うことなく、騒音を低下させることが理解できる。   Thereby, it can be understood that in this embodiment, noise is reduced without using a fiber-based silencer even when the Mach number of steam is large.

図7は、本発明の消音器5の実施例2を示すものである。該図に示す本実施例では、二種類の多孔板を、吸着層3を仕切る仕切板として配置している。即ち、多孔板形状の仕切板8Aは、多孔板形状の仕切板8Bよりも孔径が大きく形成されている。その他の構成は、実施例1と同じである。   FIG. 7 shows a second embodiment of the silencer 5 of the present invention. In this embodiment shown in the figure, two types of perforated plates are arranged as partition plates for partitioning the adsorption layer 3. That is, the porous plate-shaped partition plate 8A has a larger hole diameter than the porous plate-shaped partition plate 8B. Other configurations are the same as those in the first embodiment.

そして、本実施例では、騒音を含む蒸気が配管6を介して消音器5に流入すると、蒸気は多孔板形状の内筒4の内部を通過するが、騒音である音波は、内筒4と同心円で内筒4の外側に設置されている吸音層3に入り込む。この音波は、内筒4の多孔板形状の孔部において摩擦損失によりエネルギーを失う。また、(数1)に示すヘルムホルツ周波数(fr)と音波(騒音)の周波数が一致する場合は、吸音層3で仕切られた空間の蒸気がヘルムホルツ共鳴器として働き、音波のエネルギーの一部が共鳴器内の蒸気の振動エネルギーとして使われるため、音圧が低下する。 In the present embodiment, when steam containing noise flows into the silencer 5 via the pipe 6, the steam passes through the inner cylinder 4 having a perforated plate shape, but the sound wave that is noise is Concentric circles enter the sound absorbing layer 3 installed outside the inner cylinder 4. This sound wave loses energy due to friction loss in the perforated plate-shaped hole of the inner cylinder 4. When the Helmholtz frequency (f r ) shown in (Equation 1) and the sound wave (noise) frequency match, the vapor in the space partitioned by the sound absorbing layer 3 acts as a Helmholtz resonator, and a part of the energy of the sound wave Is used as the vibration energy of the vapor in the resonator, so the sound pressure decreases.

本実施例の消音器5に蒸気を流すと多孔板形状である内筒4では音波が発生するが、吸音層3が多孔板形状の仕切板8A及び8Bにより仕切られているため、外筒2の内壁で反射した音波のエネルギーが、多孔板形状の仕切板8A及び8Bを介して隣の吸音層3に拡散する。吸音層3の空間が完全に仕切られないことから、吸音層3の内部には、大小様々な波長の音波が発生する可能性が生じるが、これらの音波が多孔板形状の仕切板8A及び8Bの孔部を通過する際に摩擦損失を受けるため、吸音層3の内部に発生する音圧は低くなり、騒音として問題にはならない。   When steam is passed through the silencer 5 of the present embodiment, sound waves are generated in the inner cylinder 4 having the perforated plate shape, but since the sound absorbing layer 3 is partitioned by the partition plates 8A and 8B having the perforated plate shape, the outer cylinder 2 The energy of the sound wave reflected by the inner wall is diffused to the adjacent sound absorbing layer 3 through the partition plates 8A and 8B having a perforated plate shape. Since the space of the sound absorbing layer 3 is not completely partitioned, there is a possibility that sound waves of various wavelengths may be generated inside the sound absorbing layer 3, and these sound waves are generated by the partition plates 8A and 8B having a perforated plate shape. Since the frictional loss is received when passing through the hole, the sound pressure generated in the sound absorbing layer 3 is low, which does not cause a problem as noise.

更に、吸音層3の多孔板形状の仕切板8A及び8Bの孔径が異なるということは、(数2)で算出される仕切板の伝導度が異なることになる。即ち、音波が仕切板を通過する際に受ける抵抗が、仕切板毎に異なる。この場合、孔径が同じ仕切板を配置した場合よりも、音波の位相が揃いにくくなるため、一層音圧が低下する。   Further, the fact that the hole diameters of the porous plate-shaped partition plates 8A and 8B of the sound absorbing layer 3 are different means that the conductivity of the partition plate calculated by (Equation 2) is different. That is, the resistance received when sound waves pass through the partition plate is different for each partition plate. In this case, since the phases of the sound waves are less likely to be aligned than when the partition plates having the same hole diameter are arranged, the sound pressure is further reduced.

これにより、本実施例では蒸気のマッハ数が大きい場合においても、繊維系の消音材を使うことなく、騒音を低下させることができる。   Thereby, in this embodiment, even when the Mach number of steam is large, noise can be reduced without using a fiber-based silencer.

図8は、本発明の消音器5の実施例3を示すものである。該図に示す本実施例では、吸音層3を仕切る一種類の多孔板形状の仕切板8を、軸方向(蒸気の流れ方向)に異なるピッチで配置している。即ち、軸方向にランダムに多孔板形状の仕切板8が配置されている。その他の構成は、実施例1と同じである。   FIG. 8 shows a third embodiment of the silencer 5 of the present invention. In the present embodiment shown in the figure, one kind of perforated plate-like partition plates 8 for partitioning the sound absorbing layer 3 are arranged at different pitches in the axial direction (flow direction of steam). That is, the porous plate-shaped partition plates 8 are randomly arranged in the axial direction. Other configurations are the same as those in the first embodiment.

そして、本実施例では、騒音を含む蒸気が配管6を介して消音器5に流入すると、蒸気は多孔板形状の内筒4の内部を通過するが、騒音である音波は内筒4と同心円で内筒4の外側に設置されている吸音層3に入り込む。この音波は、内筒4の多孔板形状の孔部において摩擦損失によりエネルギーを失う。また、式(数1)に示すヘルムホルツ周波数(fr)と音波(騒音)の周波数が一致する場合は、吸音層3で仕切られた空間の蒸気がヘルムホルツ共鳴器として働き、音波のエネルギーの一部が共鳴器内の蒸気の振動エネルギーとして使われるため、音圧が低下する。 In the present embodiment, when steam containing noise flows into the silencer 5 through the pipe 6, the steam passes through the inner cylinder 4 having a perforated plate shape, but sound waves that are noise are concentric with the inner cylinder 4. And enters the sound absorbing layer 3 installed outside the inner cylinder 4. This sound wave loses energy due to friction loss in the perforated plate-shaped hole of the inner cylinder 4. When the Helmholtz frequency (f r ) and the sound wave (noise) frequency shown in the equation (Equation 1) coincide with each other, the vapor in the space partitioned by the sound absorbing layer 3 functions as a Helmholtz resonator, and the energy of the sound wave is reduced. Since the part is used as vibration energy of the vapor in the resonator, the sound pressure decreases.

本実施例の消音器5に蒸気を流すと多孔板形状である内筒4では音波が発生するが、吸音層3が多孔板形状の仕切板8により軸方向に仕切られているため、外筒2の内壁で反射した音波のエネルギーが多孔板形状の仕切板8を介して隣の吸音層3に拡散する。吸音層3の空間が完全に仕切られないことから、吸音層3の内部には、大小様々な波長の音波が発生する可能性が生じるが、これらの音波が多孔板形状の仕切板8の孔部を通過する際に摩擦損失を受けるため、吸音層3の内部に発生する音圧は低くなり、騒音として問題にはならない。   When steam is passed through the silencer 5 of the present embodiment, sound waves are generated in the inner cylinder 4 having a porous plate shape, but the sound absorbing layer 3 is partitioned in the axial direction by a partition plate 8 having a porous plate shape. The energy of the sound wave reflected by the inner wall of 2 diffuses to the adjacent sound absorbing layer 3 through the partition plate 8 having a perforated plate shape. Since the space of the sound absorbing layer 3 is not completely partitioned, there is a possibility that sound waves of various wavelengths may be generated inside the sound absorbing layer 3. These sound waves are generated in the holes of the partition plate 8 having a perforated plate shape. Since the friction loss is received when passing through the part, the sound pressure generated in the sound absorbing layer 3 is low, and this does not cause a problem as noise.

更に、吸音層3を仕切る一種類の多孔板形状の仕切板8を、軸方向に異なるピッチで配置、つまり、吸音層3を仕切る多孔板形状の仕切板8の設置位置の間隔が異なるということは、多孔板形状の仕切板8から隣の多孔板形状の仕切板8までの空間を音波が伝播するのにかかる時間が異なることである。この場合、多孔板形状の仕切板8を等間隔で配置した場合よりも音波の位相が揃いにくくなるため、一層音圧が低下する。   Furthermore, one type of porous plate-shaped partition plate 8 that partitions the sound absorbing layer 3 is arranged at different pitches in the axial direction, that is, the interval between the installation positions of the porous plate-shaped partition plate 8 that partitions the sound absorbing layer 3 is different. Is that the time taken for the sound wave to propagate through the space from the porous plate-shaped partition plate 8 to the adjacent porous plate-shaped partition plate 8 is different. In this case, since the phases of the sound waves are less aligned than in the case where the porous plate-shaped partition plates 8 are arranged at equal intervals, the sound pressure is further reduced.

これにより、蒸気のマッハ数が大きい場合においても、繊維系の消音材を使うことなく、騒音を低下させることができる。   Thereby, even when the Mach number of steam is large, noise can be reduced without using a fiber-based silencer.

尚、特に、図示して説明しないが、吸音層を軸方向に仕切る多孔板形状の仕切板が、その孔径や軸方向に異なるピッチ、開口率(孔の面積/仕切板の面積)が異なる2種類以上ある消音器としてもよい。また、開口率が異なる多孔板形状の仕切板を、図8に示すように、軸方向に異なるピッチで配置すれば、更なる効果が期待できる。   In particular, although not illustrated and described, the porous plate-shaped partition plate that partitions the sound absorbing layer in the axial direction has different pitches and different aperture ratios (hole area / partition plate area) in the axial direction 2 There may be more than one type of silencer. Further, if the porous plate-shaped partition plates having different aperture ratios are arranged at different pitches in the axial direction as shown in FIG. 8, further effects can be expected.

即ち、本発明は、仕切板としては孔径やピッチ、開口率をすべて同じにする必要はなく、複数種類の多孔板を用いることも本発明に含める。また、これらの多孔板である仕切板を等間隔に限定せずに、様々なピッチで配置することも本発明の特徴である。   That is, the present invention does not need to have the same hole diameter, pitch, and aperture ratio as the partition plate, and includes the use of a plurality of types of perforated plates. It is also a feature of the present invention that the partition plates, which are perforated plates, are arranged at various pitches without being limited to equal intervals.

次に、上記した消音器5が、原子力プラントや火力プラント等の騒音対策として適用される例について説明する。   Next, an example in which the above-described silencer 5 is applied as a noise countermeasure for a nuclear power plant or a thermal power plant will be described.

図9に、火力プラントに適用した例を示す。火力プラントの場合は、燃焼器10で燃焼した高圧ガスが熱交換器11を通過し、その熱交換器11を通過した高圧ガスが排気ダクト12を介して大気に放出されるが、図9に示す例では、熱交換器11と排気ダクト12の間に消音器5を設置して、発生する騒音を低下させている。   FIG. 9 shows an example applied to a thermal power plant. In the case of a thermal power plant, the high-pressure gas combusted in the combustor 10 passes through the heat exchanger 11, and the high-pressure gas that has passed through the heat exchanger 11 is released to the atmosphere through the exhaust duct 12, as shown in FIG. In the example shown, the silencer 5 is installed between the heat exchanger 11 and the exhaust duct 12 to reduce generated noise.

図10に、原子力プラントに適用した例を示す。原子力プラントの場合は、炉心(熱交換器)20からの蒸気が蒸気タービン21に入り、この蒸気タービン21を通過した蒸気は、再び炉心(熱交換器)20に戻されるが、図10に示す例では、蒸気が蒸気タービン21から炉心(熱交換器)20に戻される系統に消音器5を設置して、発生する騒音を低下させている。   FIG. 10 shows an example applied to a nuclear power plant. In the case of a nuclear power plant, steam from the core (heat exchanger) 20 enters the steam turbine 21, and the steam that has passed through the steam turbine 21 is returned to the core (heat exchanger) 20 again, as shown in FIG. In the example, the silencer 5 is installed in a system in which steam is returned from the steam turbine 21 to the core (heat exchanger) 20 to reduce generated noise.

図11に、空気圧縮機に適用した例を示す。空気圧縮機30の場合は、主に空気圧縮機30の吸気側に消音器5を設置して、発生する騒音を低下させている。   FIG. 11 shows an example applied to an air compressor. In the case of the air compressor 30, the silencer 5 is mainly installed on the intake side of the air compressor 30 to reduce the generated noise.

本発明は、原子力発電所や火力発電所等の騒音対策として好適な高温高圧環境向け消音器に適用することができる。   INDUSTRIAL APPLICABILITY The present invention can be applied to a silencer for high-temperature and high-pressure environments suitable as a noise countermeasure for nuclear power plants and thermal power plants.

1…仕切板、2…外筒、3…吸音層、4…内筒、5…消音器、6…配管、7…消音材、8、8A、8B…多孔板形状の仕切板、10…燃焼器、11…熱交換器、12…排気ダクト、20…炉心(熱交換器)、21…蒸気タービン、30…空気圧縮機。   DESCRIPTION OF SYMBOLS 1 ... Partition plate, 2 ... Outer cylinder, 3 ... Sound absorption layer, 4 ... Inner cylinder, 5 ... Silencer, 6 ... Piping, 7 ... Silencer, 8, 8A, 8B ... Perforated plate-shaped partition plate, 10 ... Combustion 11 ... heat exchanger, 12 ... exhaust duct, 20 ... core (heat exchanger), 21 ... steam turbine, 30 ... air compressor.

Claims (8)

多孔板形状の内筒と、該内筒と所定間隔をもって対向配置された外筒と、前記内筒と外筒により構成される空間から成る吸音層と、該吸音層の空間を軸方向に複数に細分化する仕切板とを備えた消音器において、
前記仕切板が、多孔板で形成されていることを特徴とする消音器。
A perforated plate-shaped inner cylinder, an outer cylinder opposed to the inner cylinder at a predetermined interval, a sound absorbing layer composed of a space constituted by the inner cylinder and the outer cylinder, and a plurality of spaces in the sound absorbing layer in the axial direction In a silencer with a partition plate that is subdivided into
A silencer, wherein the partition plate is formed of a perforated plate.
請求項1に記載の消音器において、
前記吸音層の空間を軸方向に複数に細分化する仕切板は、孔の径が同一の多孔板が隣接配置されていることを特徴とする消音器。
The silencer according to claim 1,
The silencer, wherein the partition plate that subdivides the space of the sound absorbing layer into a plurality of portions in the axial direction is adjacent to a porous plate having the same hole diameter.
請求項1に記載の消音器において、
前記吸音層の空間を軸方向に複数に細分化する仕切板は、孔の径が異なる多孔板が隣接配置されていることを特徴とする消音器。
The silencer according to claim 1,
The silencer is characterized in that the partition plate that subdivides the space of the sound absorbing layer into a plurality of portions in the axial direction is provided with adjacent porous plates having different hole diameters.
請求項3に記載の消音器において、
前記吸音層の空間を軸方向に複数に細分化する仕切板は、孔の開口率が異なることを特徴とする消音器。
The silencer according to claim 3,
The silencer according to claim 1, wherein the partition plate for dividing the space of the sound absorbing layer into a plurality of parts in the axial direction has different aperture ratios.
請求項1乃至4のいずれかに記載の消音器において、
前記吸音層の空間を軸方向に複数に細分化する仕切板は、その軸方向の間隔がランダムに配置されていることを特徴とする消音器。
The muffler according to any one of claims 1 to 4,
The silencer is characterized in that the partition plates for subdividing the space of the sound absorbing layer into a plurality of portions in the axial direction are arranged at random in the axial direction.
請求項1乃至5のいずれかの消音器を備えたことを特徴とする原子力プラント。   A nuclear power plant comprising the silencer according to claim 1. 請求項1乃至5のいずれかの消音器を備えたことを特徴とする火力プラント。   A thermal power plant comprising the silencer according to any one of claims 1 to 5. 請求項1乃至5のいずれかの消音器を備えたことを特徴とする空気圧縮機。   An air compressor comprising the silencer according to any one of claims 1 to 5.
JP2011044596A 2011-03-02 2011-03-02 Muffler Pending JP2012180792A (en)

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JPH0615814B2 (en) * 1987-05-08 1994-03-02 三菱重工業株式会社 Diffuser for silencer
JPH0849521A (en) * 1994-08-08 1996-02-20 Hino Motors Ltd Muffler
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JPH0615814B2 (en) * 1987-05-08 1994-03-02 三菱重工業株式会社 Diffuser for silencer
JPH0399771A (en) * 1989-09-08 1991-04-24 Furukawa Alum Co Ltd Manufacture of al alloy-made silencer
JPH0658131A (en) * 1992-08-05 1994-03-01 Sango Co Ltd Silencer for internal combustion engine
JPH0849521A (en) * 1994-08-08 1996-02-20 Hino Motors Ltd Muffler
JP2001164921A (en) * 1999-12-09 2001-06-19 Komatsu Ltd Exhaust muffling device
JP2006144557A (en) * 2004-11-16 2006-06-08 Mitsubishi Heavy Ind Ltd Pipe and its manufacturing method

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* Cited by examiner, † Cited by third party
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CN104421218A (en) * 2013-08-28 2015-03-18 百事德机械(江苏)有限公司 Novel square bending-flow type muffle

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