JPH09112244A - Noise eliminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively eliminate a noise without using a noise absorbing material in a noise eliminating splitter arranged in an exhaust duct and so on, by extensively setting the rate of hole area of each noise absorbing hole against the surface area of each noise eliminating splitter main body by a predetermined rate in an intermediate part against an exhaust upstream part and an exhaust downstream part. SOLUTION: A noise eliminator comprises a plurality of noise eliminating splitters 4. Each noise eliminating splitter 4 is formed of a noise eliminating splitter main body 5, and partitioning walls 7 by which the inside of the main body 5 is partitioned into a plurality of noise eliminating chambers 6, and many noise absorbing holes 10, 11 are formed on the surfaces of both side walls 8 of the main body 5. The rates of hole areas of respective noise absorbing holes 10, 11 are set to be approximately 30% in an intermediate part 12, and approximately 3% in an upstream part 13 and a downstream part 14. The noise eliminator 1 is made to serve as both an extended chamber type noise eliminating splitters in which the passage cross sectional area of an acoustic wave is changed and resonance absorption noise eliminating splitters by which the acoustic wave is absorbed and canceled, therefore, a noise can be enough eliminated without filling a noise absorbing material into the inside of the main body 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler splitter installed in, for example, an exhaust duct of power generation equipment using a gas turbine.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 8, in a power generation facility using a gas turbine 50, an exhaust heat recovery boiler 51 for recovering heat from exhaust gas generated in the gas turbine 50 is connected via an exhaust duct 52. Connected.

A muffling device (also called a duct silencer) is provided in the exhaust duct 52, and the muffling device comprises a plurality of muffling splitters 53 arranged side by side at predetermined intervals.

Conventionally, as shown in FIG. 9, the muffling splitters 53 in this muffling device are arranged side by side in an exhaust duct main body 54, and a muffling splitter main body 56 having a large number of sound absorbing holes 55 formed on the surface thereof. A partition member (also referred to as a splitter frame) 57 for partitioning the interior of the sound deadening splitter body 56, and a sound absorbing material (for example, rock wool, glass wool, ceramic fiber, etc., which is filled in a sound deadening chamber 58 partitioned by each partition member 57, is porous. The same is used) 59.

Exhaust duct 5 provided with such a silencer
According to 2, the sound is absorbed from the sound absorbing holes 55 when the exhaust gas passes through the gaps between the sound deadening splitters 53, and is effectively damped by the sound absorbing material 59 of each sound deadening chamber 58.

[0006]

In the above-described conventional silencer, although the sound deadening effect is sufficient, since the exhaust gas passing through the exhaust duct 54 is at a high temperature and at a high speed, the sound absorbing material 59 is greatly deteriorated and the sound deadening effect is reduced. There is a problem that is short.

Therefore, an object of the present invention is to provide a silencer capable of solving the above problems.

[0008]

Means for solving the problems of the present invention comprises means for silencing splitters provided in a heat flow path formed by a box and arranged side by side at predetermined intervals. A plurality of sound absorbing holes are formed on the surface of each muffling splitter body, and the open area ratio, which is the total area of each sound absorbing hole to the surface area of each muffling splitter body, is the exhaust upstream of each muffling splitter body. And a portion downstream of the exhaust gas are set to be larger in the intermediate portion by a predetermined ratio.

Further, a plurality of sound absorbing holes are formed in the exhaust upstream part and the intermediate part of each muffling splitter body,
The open area ratio, which is the total area of each sound absorbing hole with respect to the surface area of each muffling splitter body, is set to be larger by a predetermined ratio in the intermediate portion than the exhaust upstream portion of each muffling splitter body.

Further, a plurality of sound absorbing holes are formed in the exhaust downstream portion and the intermediate portion of each sound deadening splitter body, and the open area ratio, which is the total area of the sound absorbing holes with respect to the surface area of each sound deadening splitter body, is the sound deadening splitter. The intermediate portion is set to be larger than the exhaust downstream portion of the main body by a predetermined ratio.

The sound wave passing through the heat flow path of the box is
When passing between a plurality of muffler splitters that are placed side by side with a predetermined spacing from each other, first pass through a small cross-sectional area between the upstream parts of each muffler splitter body with a small aperture ratio, and then It passes through the large cross-sectional area portion of the middle portion where the porosity is set large, and again passes through the small cross-sectional area portion between the downstream portions. At this time, sound waves are reflected at the portion where the passage cross-sectional area becomes discontinuous while passing between the silencer splitter bodies, the energy is attenuated, and the upstream portion, the intermediate portion, and the downstream portion of each silencer splitter body. The sound absorbing holes enter into the main body of each of the sound absorbing splitters, and the sound waves are canceled out by the resonance due to resonance.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. As shown in the overall perspective view of FIG.
The silencer 1 according to the embodiment of the present invention is provided in a power generation facility using a gas turbine, and is provided between a gas turbine and an exhaust heat recovery boiler that recovers heat from exhaust gas generated in the gas turbine. It is arranged in the exhaust flow path 3 in the box-shaped exhaust duct 2 to be arranged.

The muffler 1 is composed of a plurality (six in the figure) of muffling splitters 4 which are arranged side by side at a predetermined distance from each other. As shown in the perspective view of FIG. 4 is a silencer splitter body (splitter frame) whose upstream end is formed in an arc shape.
5 and a partition wall 7 for partitioning the inside of the sound deadening splitter body 5 into a plurality of sound deadening chambers 6, and on the surfaces of both side walls 8 of the sound deadening splitter body 5, a large number of sound absorbing holes 10, 11 having the same diameter are provided. Has been formed.

The open area ratio, which is the total area of the sound absorbing holes 10 and 11 with respect to the side wall surface area of the sound deadening splitter main body 5, is 30% in the intermediate portion 12 (for example, 65,000 pieces having a diameter of 5φ), and the upstream side. The diameter and the number of sound absorbing holes 10 and 11 (for example, 200 having a diameter of 32φ) are set so that each of the portions 13 and the downstream portion 14 becomes 3% (for example, ⅛ of the intermediate portion 12). .

FIG. 3 is a model of the horizontal cross-sectional area between the sound deadening splitter bodies 5 in consideration of the areas of the sound absorbing holes 10 and 11. The sound wave 15 passing between the sound deadening splitter bodies 5 is reduced. As for the volume, the passage areas S1 of the upstream portion 13 and the downstream portion 14 between the silencing splitter bodies 5 and the intermediate portion 1
It is determined by the passage area S2 of 2 and the length L of the intermediate portion 12.

In the muffler 1 constructed as described above, the sound wave 15 generated on the gas turbine side first has a small cross-sectional area (S1) between the upstream parts of the respective muffler splitter bodies 5 with a small aperture ratio. After passing through the large cross-sectional area portion (S2) of the intermediate portion 12 in which the aperture ratio is set to a large value, and again through the small cross-sectional area portion (S1) between the downstream portions, between the silencer splitter bodies 5 The energy is attenuated by the reflection of the sound wave due to the change of the cross section while passing through, and the upstream portion 1 of each muffling splitter body 5 progresses.
3, the middle portion 12, and the sound absorbing holes 10 and 11 of both side walls 8 of the downstream portion 14 enter the respective silencer splitter bodies 5 and are silenced by resonance of the sound waves 15.

FIG. 4 shows a comparison of the volume reduction (dB) of the conventional silencer (shown by a broken line) shown in FIG. 9 and the silencer 1 (shown by a solid line) in the embodiment of the present invention. Then, from this graph, the measured frequency (31.5 Hz ~
8000 Hz) Silencer 1 of the present embodiment in all ranges
It can be seen that the noise reduction effect is better (3 dB to 50 dB).

As described above, according to the muffling device 1 of the embodiment of the present invention, the opening ratios of the sound absorbing holes 10 and 11 formed in the muffling splitter body 5 are changed in the upstream portion 13, the downstream portion 14 and the intermediate portion 12. By doing so, it serves as both an expansion chamber type muffling splitter in which the passage cross-sectional area of the sound wave changes and a resonance absorption type muffling splitter that absorbs and cancels the sound wave in the muffling splitter body 5, and the sound deadening is the same as in the conventional case. It is possible to sufficiently muffle sound without filling the interior of the splitter body 5 with a sound absorbing material. By not using the sound absorbing material in this manner, the exhaust duct 2 connected to the gas turbine
Even if the internal temperature becomes high, as described above, it is possible to use the product for a long period of time while maintaining a certain silencing effect.

In the above embodiment, each sound absorbing hole 1
The diameter and number of 0, 11 and the width of the partition wall 7 (volume of each muffling chamber 6 in the muffler splitter body 5) and the wall thickness of each side wall 8 were varied to meet the noise level and frequency characteristics of the sound source. Of course, it is possible to mute.

5 and 6, the muffling device 1 in which the first muffling splitter body 20 and the second muffling splitter body 21 are arranged side by side in the exhaust duct 2 from the upstream side to the downstream side of the exhaust duct 2. In this case, the upstream part 2 of the first silencing splitter body 20 is shown.
2, the downstream portion 23 and the downstream portion 24 of the second silencing splitter body have a low aperture ratio, and the first silencing splitter body 2
The aperture ratio of the intermediate portion 25 of 0, the upstream portion 26 and the intermediate portion 27 of the second silencing splitter body 21 is increased.

Also in this configuration, as in the above-described embodiment, the sound wave 15 travels while attenuating the energy, and enters the respective silencing splitter bodies from both side walls,
Reflected by the change in cross-sectional area, cancel each other out, and the sound is surely muted.

Further, although not shown, a plurality of sound absorbing holes are formed only in the upstream and intermediate portions of both side walls of each silencing splitter body, and the opening ratio of each portion is set to the upstream portion of each silencing splitter body. The middle part may be set to be larger by a predetermined ratio, or a plurality of sound absorbing holes may be formed only in the downstream part and the middle part of both side walls of each muffling splitter main body, and the opening ratio of each part may be adjusted by each muffling splitter. The intermediate portion may be set larger than the downstream portion by a predetermined ratio.

Also in this case, as in the above-described embodiment, the double-sided expansion chamber-type and resonance-absorption-type sound deadening splitters are also used, and the sound wave is not cross-sectioned while passing between the sound deadening splitter bodies without providing a sound absorbing material. As the sound wave is reflected by the change, the energy progresses while being attenuated, and the sound absorbing holes on both side walls enter the respective silencer splitter bodies to be silenced by the resonance of the sound absorbing holes. Can be used for a long period of time while maintaining a certain noise reduction effect.

FIG. 7 shows the volume reduction in the case of this embodiment. As in the case of the above embodiment, most of the measured frequencies (31.5 Hz to 8000 Hz) are lower than those of the conventional silencer. It can be seen that the volume reduction is excellent.

[0025]

As is apparent from the above description, according to the present invention, the opening ratios of the sound absorbing holes formed in the silencing splitter bodies provided side by side in the box are set to the exhaust upstream portion and the exhaust downstream portion of each silencing splitter body. On the other hand, since it was set to be larger by a predetermined ratio in the middle part, there are an expansion chamber type muffling splitter that changes the cross-sectional area of the sound wave and a resonance absorption type muffling splitter that cancels the sound wave by resonance of the sound absorbing hole on the surface of the muffling splitter body. Therefore, it is possible to sufficiently muffle sound without filling the inside of the sound deadening splitter body with the sound absorbing material as in the conventional case. Even when used, a certain silencing effect can be maintained for a long time.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an overall configuration of a silencer showing an embodiment of the present invention.

FIG. 2 is also a perspective view of each silencer unit alone.

FIG. 3 is a model diagram in which the horizontal cross-sectional area between the respective sound deadening splitter bodies is modeled in consideration of the area of each sound absorbing hole.

FIG. 4 is a graph showing a comparison of the volume reductions of the silencer according to the embodiment of the present invention and the conventional silencer.

FIG. 5 is a perspective view showing an overall configuration of a silencer according to another embodiment.

FIG. 6 is a schematic plan view of each muffling splitter.

FIG. 7 is a graph showing a comparison of the volume reductions of the silencer according to another embodiment of the present invention and the conventional silencer.

FIG. 8 is an overall schematic diagram of a power generation facility using a gas turbine.

FIG. 9 is a perspective view of a conventional silencer splitter.

[Explanation of symbols]

 1 muffling device 2 exhaust duct 3 exhaust flow path 4 muffling splitter 5 muffling splitter body 6 muffling chamber 7 partition wall 8 side wall 10 sound absorbing hole 11 sound absorbing hole 12 middle part 13 upstream part 14 downstream part 15 sound wave S1 passages in upstream and downstream parts Area S2 Intermediate passage area

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor repair Hideyuki Nishikojo 5-328, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. No. 28 in Hitachi Shipbuilding Co., Ltd.

Claims (3)

[Claims] 1. A silencer comprising a plurality of silencer splitters provided in a heat flow path formed by a box and arranged side by side at a predetermined interval from each other, wherein a plurality of silencer splitters are provided on the surface of each silencer splitter body. The sound absorbing holes are formed, and the open area ratio, which is the total area of each sound absorbing hole with respect to the surface area of each muffling splitter body, is increased by a predetermined ratio in the middle part of the exhaust upstream part and the exhaust downstream part of each muffling splitter body. A silencer characterized by being set. 2. A silencer comprising a plurality of silencer splitters provided in a heat flow path formed by a box body and arranged side by side at a predetermined interval from each other, the exhaust upstream of each silencer splitter body. A plurality of sound absorbing holes are formed in each of the sound absorbing portion and the middle portion, and the open area ratio, which is the total area of the sound absorbing holes with respect to the surface area of each sound deadening splitter body, is a predetermined value in the middle portion with respect to the exhaust upstream portion of each sound deadening splitter body. A silencer characterized by being set to a large proportion. 3. A muffler comprising a plurality of muffler splitters provided in a heat flow path formed by a box body and arranged side by side at a predetermined distance from each other, the exhaust muffler downstream of each muffler splitter body. A plurality of sound absorbing holes are formed in each of the sound absorbing part and the intermediate part, and the open area ratio, which is the total area of each sound absorbing hole with respect to the surface area of each sound deadening splitter body, has a predetermined value in the middle part with respect to the exhaust downstream part of each sound deadening splitter body. A silencer characterized by being set to a large proportion.