JP6579924B2 - Chimney noise reduction system and setting method of chimney noise reduction system - Google Patents

Description

  The present disclosure relates to a chimney noise reduction system and a setting method of the chimney noise reduction system.

  Non-Patent Document 1 discloses a duct silencing control device capable of reducing noise propagating in a duct. The duct silencing control device includes a reference microphone capable of detecting noise in the duct, a control sound source capable of emitting sound waves in the duct, and an error microphone capable of detecting sound waves not canceled out by sound waves emitted by the control sound source. And a control device capable of adjusting the sound wave emitted from the control sound source based on the detection results of the reference microphone and the error microphone.

  On the other hand, the noise reduction device disclosed in Patent Document 1 has sound pressure reduction means, and the sound pressure reduction means is constituted by an acoustic tube or a resonator disposed around the upper end opening of the chimney. The acoustic tube and the resonator are constituted by a container opened upward, and the frequency of noise to be reduced is determined by the length and volume of the container.

  The active sound insulation wall disclosed in Patent Document 2 is provided with a sound insulation wall installed in parallel to the moving direction of the sound source, a plurality of noise detection means arranged along the sound insulation wall, and a plurality of installations corresponding to the noise detection means. The noise canceling sound generating means, the noise detecting means and the noise canceling generating means are installed to generate noise canceling from the noise canceling sound generating means based on the noise generated by the sound source detected by the noise detecting means. Noise canceling sound calculation for calculating a signal for the purpose. According to the active sound insulation wall disclosed in Patent Document 2, the noise radiated from the sound source leaking from the upper end of the sound insulation wall to the outside of the sound insulation wall can be directly canceled by the noise canceling sound emitted from the noise canceling sound generating means. it can.

JP 2004-94065 A Japanese Patent No. 3581645

Masaharu Nishimura, “Duct Silence Control by ANC”, Journal of Precision Engineering, May 5, 1998, Vol. 64, No. 5, p. 669-673

According to the knowledge of the present inventors, there are two types of noise radiated from the vicinity of the upper end opening of the chimney.
Of these, the first noise is the noise that has propagated through the chimney, and this type of noise has a certain frequency. When this sound wave is emitted from the top opening of the chimney, it propagates as noise to people on the ground.
The second noise is noise caused by the fluid flowing out from the upper end opening of the chimney. The fluid flowing out from the upper end opening of the chimney forms a region (pressure variation irregular region) in which the pressure varies irregularly above the upper end opening. A stable sound wave is not formed inside the irregular region of pressure fluctuation, but an outward sound wave is formed at the outer edge of the irregular region of pressure fluctuation. This sound wave propagates as noise to people on the ground. The second noise generally has a wider frequency distribution than the first noise.

Here, the duct silencing control device disclosed in Non-Patent Document 1 is effective in reducing the first noise propagating in the duct, but in reducing the second noise formed by the fluid after flowing out of the duct. Is not valid.
The acoustic tube and the resonator applied to the noise reduction device disclosed in Patent Document 1 are excellent in reducing sound waves having a specific frequency, and the first noise having a specific frequency that has propagated through the chimney. It is considered effective for the reduction of noise but is not effective for the second noise having a wide frequency distribution. In addition, since the frequency distribution of the second noise is defined by the fluid flow, it is not easy to accurately grasp.
On the other hand, the active sound insulation wall disclosed in Patent Document 2 is not intended to reduce the noise of the chimney, and does not mention cancellation of noise that propagates downward from the upper end of the sound insulation wall.

In the first place, in Non-Patent Document 1, Patent Document 1 and Patent Document 2, an area where pressure fluctuation is irregular is formed above the upper end opening by the fluid flowing out from the upper end opening of the chimney, and the inside of the chimney is formed at the outer edge of this area. Apart from the first noise that has propagated, there is no mention of the formation of the second noise.
In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a chimney noise reduction system and chimney noise that can reduce noise generated and radiated by fluid that has flowed out of the upper end opening of the chimney regardless of frequency. It is to provide a method for setting a reduction system.

(1) A chimney noise reduction system according to at least one embodiment of the present invention includes:
A diffractive portion that is arranged at a distance from the upper end opening of the chimney in the radial direction of the upper end opening and extends in a horizontal direction intersecting the radial direction,
A sound insulation part extending downward from the diffraction part;
A plurality of reference microphones arranged along the extending direction of the diffractive portion, each capable of detecting sound waves;
A plurality of speakers arranged along the extending direction of the diffractive portion, each capable of emitting sound waves;
At least one control device capable of adjusting sound waves radiated by each of the plurality of speakers based on sound waves detected by each of the plurality of reference microphones;
With
The diffractive part is disposed away from an irregular region where the pressure fluctuation generated above the upper end opening of the chimney is caused by the fluid flowing out from the upper end opening of the chimney, and is formed at the outer edge of the irregular region. is the noisy sound wave that propagates toward the diffractive portion, the sound insulation part and in cooperation are adapted to diffract downward is,
Each of the plurality of reference microphones, the noise wave formed by the outer edge of the region is detectably arranged,
Each of said plurality of speakers, sound waves each of said plurality of speakers is radiated is disposed so as to overlap with the noise wave formed by the outer edge of said region,
The control device adjusts the sound wave emitted from each of the plurality of speakers so that the sound wave emitted from each of the plurality of speakers cancels out the noise wave diffracted downward by the diffraction unit. is configured to,
The diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged so as to face only a part of the upper end opening of the chimney in the circumferential direction of the chimney, and the diffraction unit, the plurality of reference microphones, and The plurality of speakers are rotatable in a circumferential direction of the chimney .

According to the configuration (1), the diffractive portion is arranged away from the irregular region of pressure fluctuation (pressure fluctuation irregular region) formed by the fluid flowing out from the upper end opening of the chimney. It is possible to reliably diffract the sound wave (noise wave) that is formed and propagated at the outer edge.
In addition, each of the plurality of reference microphones is disposed so as to be able to detect a sound wave formed at the outer edge of the pressure fluctuation irregular region, and each of the plurality of loudspeakers has a sound wave (quenched sound) emitted by itself. It arrange | positions so that it may overlap with the noise wave formed in the outer edge of a fluctuation irregular area | region.
For this reason, according to the above configuration (1), the control device adjusts the silencing sound radiated from each of the plurality of speakers, thereby converting the noise wave diffracted downward by the diffraction unit into the plurality of speakers. Each of these can be canceled out by the silenced sound emitted. Thereby, noise reaching the ground from the upper end opening of the chimney can be reduced regardless of the frequency.
In particular, according to the configuration (1), by diffracting the noise wave by the diffracting unit, it is possible to match the propagation direction of the diffracted noise wave and the propagation direction of the silencer. For this reason, it is possible to superimpose a noise wave and a silencer having opposite phases over a wide spatial range, and to reduce noise reaching the ground.
In addition, according to the configuration (1), noise reaching the ground from the chimney upper end opening in the direction in which the diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged as viewed from the upper end opening of the chimney regardless of the frequency. By changing the position of the diffraction section, the plurality of reference microphones and the plurality of speakers by rotation around the chimney, the noise reaching the ground from the top opening of the chimney in any direction can be reduced in frequency. Regardless of whether it can be reduced.

(2) A chimney noise reduction system according to at least one embodiment of the present invention includes:
A diffractive portion that is arranged at a distance from the upper end opening of the chimney in the radial direction of the upper end opening and extends in a horizontal direction intersecting the radial direction,
A sound insulation part extending downward from the diffraction part;
A plurality of reference microphones arranged along the extending direction of the diffractive portion, each capable of detecting sound waves;
A plurality of speakers arranged along the extending direction of the diffractive portion, each capable of emitting sound waves;
At least one control device capable of adjusting sound waves radiated by each of the plurality of speakers based on sound waves detected by each of the plurality of reference microphones;
With
The diffractive part is disposed away from an irregular region where the pressure fluctuation generated above the upper end opening of the chimney is caused by the fluid flowing out from the upper end opening of the chimney, and is formed at the outer edge of the irregular region. The noise wave propagating toward the diffraction part is configured to diffract downwardly in cooperation with the sound insulation part,
Each of the plurality of reference microphones is arranged to be able to detect the noise wave formed at the outer edge of the region,
Each of the plurality of speakers is arranged such that sound waves emitted from each of the plurality of speakers overlap with the noise wave formed at the outer edge of the region,
The control device adjusts the sound wave emitted from each of the plurality of speakers so that the sound wave emitted from each of the plurality of speakers cancels out the noise wave diffracted downward by the diffraction unit. Configured to
The diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged so as to face only a part of the upper end opening of the chimney in the circumferential direction of the chimney, and the diffraction unit in the circumferential direction of the chimney The length of is variable.

According to the configuration (2), since the diffractive portion is arranged away from the irregular region of pressure fluctuation (pressure fluctuation irregular region) formed by the fluid flowing out from the upper end opening of the chimney, the region It is possible to reliably diffract the sound wave (noise wave) that is formed and propagated at the outer edge.
In addition, each of the plurality of reference microphones is disposed so as to be able to detect a sound wave formed at the outer edge of the pressure fluctuation irregular region, and each of the plurality of loudspeakers has a sound wave (quenched sound) radiated by itself. It arrange | positions so that it may overlap with the noise wave formed in the outer edge of a fluctuation irregular area | region.
For this reason, according to the above configuration (2), the control device adjusts the silenced sound radiated from each of the plurality of speakers, thereby converting the noise wave diffracted downward by the diffraction unit into the plurality of speakers. Each of these can be canceled out by the silenced sound emitted. Thereby, noise reaching the ground from the upper end opening of the chimney can be reduced regardless of the frequency.
In particular, according to the configuration (2), the noise wave is diffracted by the diffracting unit, so that the propagation direction of the diffracted noise wave can coincide with the propagation direction of the silencer. For this reason, it is possible to superimpose a noise wave and a silencer having opposite phases over a wide spatial range, and to reduce noise reaching the ground.
Further, according to the configuration (2), noise reaching the ground from the upper end opening of the chimney in the direction in which the diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged as viewed from the upper end opening of the chimney, regardless of the frequency. By changing the length of the diffraction part in the circumferential direction of the chimney, the noise reaching the ground from the upper end opening of the chimney can be varied in any range in the circumferential direction of the chimney regardless of the frequency. Can be reduced.

(3) In some embodiments, in the configuration (1) or (2),
A plurality of error microphones arranged along the extending direction of the diffractive part and capable of detecting the noise wave diffracted downward by the diffractive part together with the sound wave radiated from each of the plurality of speakers Further comprising
The at least one control device is capable of adjusting the sound wave radiated from each of the plurality of speakers based on the noise wave and the sound wave detected by each of the plurality of error microphones.

In the configuration (3), by adjusting the sound wave radiated from each of the plurality of speakers based on the detection result of the error microphone, the noise wave formed at the outer edge of the pressure fluctuation irregular region is changed over time. Even if it changes, the noise wave diffracted downward by the diffraction part can be reliably reduced regardless of the frequency.

(4) In some embodiments, in the configuration (1) or (3),
The length of the diffraction part in the circumferential direction of the chimney is variable.
In the configuration (4), by changing the length of the diffractive portion in the circumferential direction of the chimney, the noise reaching the ground from the upper end opening of the chimney in any range in the circumferential direction of the chimney regardless of the frequency Can be reduced.

(5) In some embodiments, in any one of the configurations (1) to (4),
  The distance provided between the upper end opening of the chimney and the diffraction part is variable.
  Roughly speaking, although the noise wave is formed at the outer edge of the pressure fluctuation irregular region, the position formed by the frequency, that is, the distance from the top opening of the chimney differs. By utilizing this, in the above configuration (5), the frequency of the noise wave to be reduced can be changed by changing the distance provided between the upper end opening of the chimney and the diffractive portion, thereby reducing the chimney noise. The frequency characteristics required for the system can be easily realized.

(6) In some embodiments, in any one of the configurations (1) to (5),
The position of the diffraction part in the vertical direction is variable.
In the vicinity of the upper end opening of the chimney, the propagation direction of the noise wave may be bent by the flow of wind. In this respect, in the above configuration (6), the position of the diffractive portion in the vertical direction is variable, and the height of the diffractive portion can be adjusted according to the propagation direction of the noise wave. It can be reduced regardless of the flow.

(7) In some embodiments, in the configuration (6),
The diffractive portion can be disposed above the upper end opening of the chimney in the vertical direction.
In the vicinity of the upper end opening of the chimney, the propagation direction of the noise wave may be bent by the flow of wind. For this reason, if the upper end opening of the chimney and the height of the diffraction part are the same, the noise wave may propagate to the ground beyond the diffraction part without being diffracted. In this respect, in the above configuration (7), by arranging the diffractive part above the upper end opening of the chimney, it is possible to prevent the noise wave from diffracting and not exceeding the diffractive part, and to reduce the noise reaching the ground. It can be reduced regardless of the wind flow in the sky.

(8) In some embodiments, in the above configurations (1) to (7),
The sound insulation part has a variable length in the vertical direction.
In the above configuration (8), by adjusting the length of the sound insulation part in the vertical direction, the noise insulation part directly blocks the propagation of noise waves, and further reduces the noise reaching the ground regardless of the frequency. Can do.

(9) In some embodiments, in any one of the above configurations (1) to (8),
The distance between the chimney and the sound insulation part is variable.
In the above configuration (9), by reducing the distance between the sound insulation part and the chimney, the propagation of the noise wave in the gap between the chimney and the sound insulation part is interrupted, and the noise reaching the ground depends on the frequency. Further reduction can be achieved.

(10) In some embodiments, in the configuration (9),
The sound insulation part is swingable so that a distance between a lower end side of the sound insulation part and the chimney changes.
In the above configuration (10), the propagation of the noise wave in the gap between the chimney and the sound insulation part is blocked by swinging the sound insulation part so that the distance between the lower end side of the sound insulation part and the chimney is shortened. The noise reaching the ground can be further reduced regardless of the frequency.

(11) In some embodiments, in any one of the above configurations (1) to (10),
A sound absorbing part is further provided between the sound insulating part and the chimney.
In the configuration (11), the noise wave propagating through the gap between the chimney and the sound insulation part can be reduced by the sound absorbing part, and the noise reaching the ground can be further reduced regardless of the frequency.

(12) In some embodiments, in any one of the above configurations (1) to (11),
The chimney has a step portion that protrudes laterally from the upper end opening, below the upper end opening,
The sound insulation part is attached to the step part.
  In said structure (12), a sound insulation part can be arrange | positioned by a simple structure by attaching a sound insulation part to the step part of a chimney.

(13) A method for adjusting a chimney noise reduction system according to at least one embodiment of the present invention includes:
A diffractive portion that is disposed at a distance from the upper end opening of the chimney in the radial direction of the upper end opening and extends along a horizontal direction intersecting the radial direction;
A sound insulation part extending downward from the diffraction part;
A plurality of reference microphones arranged along the extending direction of the diffractive portion, each capable of detecting sound waves;
A plurality of speakers arranged along the extending direction of the diffractive portion, each capable of emitting sound waves;
At least one control device capable of adjusting sound waves radiated by each of the plurality of speakers based on sound waves detected by each of the plurality of reference microphones;
With
The diffractive part is disposed away from an irregular region where the pressure fluctuation generated above the upper end opening of the chimney is caused by the fluid flowing out from the upper end opening of the chimney, and is formed at the outer edge of the irregular region. The noise wave propagating toward the diffraction part is configured to diffract downwardly in cooperation with the sound insulation part,
Each of the plurality of reference microphones is arranged to be able to detect the noise wave formed at the outer edge of the region,
Each of the plurality of speakers is arranged such that sound waves emitted from each of the plurality of speakers overlap with the noise wave formed at the outer edge of the region,
The control device adjusts the sound wave emitted from each of the plurality of speakers so that the sound wave emitted from each of the plurality of speakers cancels out the noise wave diffracted downward by the diffraction unit. Configured to
The diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged so as to face only a part of the upper end opening of the chimney in the circumferential direction of the chimney, and the diffraction unit, the plurality of reference microphones, and The plurality of speakers is a method for adjusting a chimney noise reduction system that is rotatable in a circumferential direction of the chimney,
A plurality of error microphones capable of detecting the noise wave diffracted downward by the diffraction unit along with the sound wave radiated from each of the plurality of speakers is disposed along the extending direction of the diffraction unit. And
Adjusting the setting of the at least one control device based on the noise wave and the sound wave detected by each of the plurality of error microphones;
After the setting of the at least one control device is adjusted, the plurality of error microphones are removed.

( 14 ) A method for adjusting a chimney noise reduction system according to at least one embodiment of the present invention comprises:
A diffractive portion that is disposed at a distance from the upper end opening of the chimney in the radial direction of the upper end opening and extends along a horizontal direction intersecting the radial direction;
A sound insulation part extending downward from the diffraction part;
A plurality of reference microphones arranged along the extending direction of the diffractive portion, each capable of detecting sound waves;
A plurality of speakers arranged along the extending direction of the diffractive portion, each capable of emitting sound waves;
At least one control device capable of adjusting sound waves radiated by each of the plurality of speakers based on sound waves detected by each of the plurality of reference microphones;
With
The diffractive part is disposed away from an irregular region where the pressure fluctuation generated above the upper end opening of the chimney is caused by the fluid flowing out from the upper end opening of the chimney, and is formed at the outer edge of the irregular region. is the noisy sound wave that propagates toward the diffractive portion, the sound insulation part and in cooperation are adapted to diffract downward is,
Each of the plurality of reference microphones, the noise wave formed by the outer edge of the region is detectably arranged,
Each of said plurality of speakers, sound waves each of said plurality of speakers is radiated is disposed so as to overlap with the noise wave formed by the outer edge of said region,
The control device adjusts the sound wave emitted from each of the plurality of speakers so that the sound wave emitted from each of the plurality of speakers cancels out the noise wave diffracted downward by the diffraction unit. is configured to,
The diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged so as to face only a part of the upper end opening of the chimney in the circumferential direction of the chimney, and the diffraction unit in the circumferential direction of the chimney Is a method of adjusting a chimney noise reduction system , the length of which is variable ,
A plurality of error microphones capable of detecting the noise wave diffracted downward by the diffraction unit along with the sound wave radiated from each of the plurality of speakers is disposed along the extending direction of the diffraction unit. And
Adjusting the setting of the at least one control device based on the noise wave and the sound wave detected by each of the plurality of error microphones;
After the setting of the at least one control device is adjusted, the plurality of error microphones are removed.

If there is no particular change in the flow of the fluid discharged from the chimney, once the control device is set, there is no need to change it later. Therefore, in the configurations ( 13 ) and (14) , the configuration of the remaining chimney noise reduction system can be simplified by arranging the error microphone once and then removing it.

  According to at least one embodiment of the present invention, there is provided a chimney noise reduction system and a chimney noise reduction system setting method capable of reducing noise generated and radiated by a fluid flowing out from an upper end opening of the chimney regardless of frequency. Provided.

It is a figure showing a schematic structure of a gas turbine power generation system to which a chimney noise reduction system concerning one embodiment of the present invention is applied. It is a figure which shows roughly the cross section of the chimney noise reduction system of FIG. 1 with the upper end opening side of a chimney. It is a top view which shows roughly the chimney noise reduction system of FIG. 1 with a chimney. It is the schematic for demonstrating the effect of the chimney noise reduction system of FIG. It is a figure for demonstrating the schematic structure of the chimney noise reduction system which concerns on other embodiment. It is a figure for demonstrating the schematic structure of the chimney noise reduction system which concerns on other embodiment. It is a figure for demonstrating the schematic structure of the control apparatus applied to the chimney noise reduction system of FIG. It is a figure for demonstrating the schematic structure of the control apparatus applied to the chimney noise reduction system which concerns on other embodiment. It is a figure for demonstrating the schematic structure of the control apparatus applied to the chimney noise reduction system of FIG. It is a top view which shows the schematic structure of the chimney noise reduction system which concerns on other embodiment with a chimney. It is a top view which shows the schematic structure of the chimney noise reduction system which concerns on other embodiment with a chimney. It is a top view which shows the schematic structure of the chimney noise reduction system which concerns on other embodiment with a chimney. It is a top view which shows the schematic structure of the chimney noise reduction system which concerns on other embodiment with a chimney. It is a top view which shows the schematic structure of the chimney noise reduction system which concerns on other embodiment with a chimney. It is a figure which shows schematically the cross section of a chimney noise reduction system along the XV-XV line | wire in FIG. 14 with the upper end opening side of a chimney. It is a top view which shows the schematic structure of the chimney noise reduction system which concerns on other embodiment with a chimney. It is a top view which shows schematic structure of the chimney noise reduction system of FIG. 16 in another state with a chimney. It is a figure which shows schematically the cross section of a chimney noise reduction system along the XVIII-XVIII line | wire in FIG. 16 with the upper end opening side of a chimney. It is a figure which shows schematically the cross section of the chimney noise reduction system which concerns on other embodiment with the upper end opening side of a chimney. FIG. 20 is a diagram schematically showing a cross section of the chimney noise reduction system of FIG. 19 in another state along with the upper end opening side of the chimney. It is a figure which shows schematically the cross section of the chimney noise reduction system which concerns on other embodiment with the upper end opening side of a chimney. It is a figure which shows schematically the cross section of the chimney noise reduction system which concerns on other embodiment with the upper end opening side of a chimney. It is a figure which shows schematically the cross section of the chimney noise reduction system which concerns on other embodiment with the upper end opening side of a chimney. It is a figure which shows schematically the cross section of a chimney noise reduction system with the upper end opening side of a chimney. It is a flowchart which shows the schematic procedure of the setting method of the chimney noise reduction system which concerns on one Embodiment of this invention.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
For example, an expression indicating that things such as “identical”, “equal”, and “homogeneous” are in an equal state not only represents an exactly equal state, but also has a tolerance or a difference that can provide the same function. It also represents the existing state.
For example, expressions representing shapes such as quadrangular shapes and cylindrical shapes represent not only geometrically strict shapes such as quadrangular shapes and cylindrical shapes, but also irregularities and chamfers as long as the same effects can be obtained. A shape including a part or the like is also expressed.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one constituent element are not exclusive expressions for excluding the existence of the other constituent elements.

FIG. 1 shows a schematic configuration of a gas turbine power generation system 2 to which a chimney noise reduction system 1 (1a) according to an embodiment of the present invention is applied. The gas turbine power generation system 2 includes a gas turbine 3, a generator 4, an exhaust gas treatment device 6, and a chimney 8, and the chimney noise reduction system 1 is applied to the chimney 8.
The gas turbine 3 includes a compressor 10, a combustor 12, and a turbine 14, and the compressor 10 can compress air using a part of the power output from the turbine 14. The combustor 12 burns fuel using the air compressed by the compressor 10 to generate high-temperature and high-pressure combustion gas (exhaust gas). The energy of the combustion gas is converted into power by the turbine 14, and the generator 4 is operated by this power. The exhaust gas discharged from the turbine 14 is purified by the exhaust gas processing device 6 and then released into the atmosphere through the chimney 8.

  The exhaust gas treatment device 6 is not particularly limited as long as it can purify the exhaust gas. For example, an exhaust heat recovery boiler may be used. In this case, the steam turbine may be operated with the steam obtained by the exhaust heat recovery boiler, and the generator 4 or another generator may be operated with the steam turbine.

  FIG. 2 is a view schematically showing a cross section of the chimney noise reduction system 1 (1a) together with the upper end opening 8a side of the chimney 8. As shown in FIG. 3 is a plan view schematically showing the chimney noise reduction system 1 (1a) together with the chimney 8, and the cross section of the chimney noise reduction system 1 (1a) in FIG. 2 is taken along the line II-II in FIG. ing. FIG. 4 is a schematic diagram for explaining the operational effects of the chimney noise reduction system 1 (1a to 1o).

  5 and 6 are diagrams for explaining a schematic configuration of a chimney noise reduction system 1 (1b, 1c) according to another embodiment. FIG. 7 is a diagram for explaining a schematic configuration of a control device applied to the chimney noise reduction system 1 (1b). FIG. 8 is a diagram for explaining a schematic configuration of a control device applied to the chimney noise reduction system 1 (1d) according to another embodiment. FIG. 9 is a diagram for explaining a schematic configuration of a control device applied to the chimney noise reduction system 1 (1a).

  FIGS. 10-14 is a top view which shows the schematic structure of the chimney noise reduction system 1 (1e, 1f, 1g, 1h, 1i) which concerns on other embodiment with the chimney 8, respectively. 15 is a diagram schematically showing a cross section of the chimney noise reduction system 1 (1i) along the line XV-XV in FIG. 14 together with the upper end opening 8a side of the chimney 8. As shown in FIG.

FIG.16 and FIG.17 is a top view which shows the schematic structure of the chimney noise reduction system 1 (1j) which concerns on other embodiment with the chimney 8, respectively. 18 is a diagram schematically showing a cross section of the chimney noise reduction system 1 (1j) along the line XVIII-XVIII in FIG. 16 together with the upper end opening 8a side of the chimney 8. As shown in FIG.
19-24 is a figure which shows schematically the cross section of the chimney noise reduction system 1 (1k, 1l, 1m, 1n, 1o) with the upper end opening 8a side of the chimney 8, respectively.

As shown in FIGS. 2 to 24, the chimney noise reduction system 1 (1a to 1o) includes a diffraction unit 20, a sound insulation unit 21, a plurality of reference microphones (reference microphones) 22, and a plurality of speakers 24, respectively. And at least one control device 26.
The diffractive portion 20 is arranged at a distance from the upper end opening 8a of the chimney 8 in the radial direction of the upper end opening 8a (the radial direction of the chimney 8), and extends in the horizontal direction intersecting the radial direction of the upper end opening 8a. Exist.

The sound insulation part 21 extends downward from the diffraction part 20.
The plurality of reference microphones 22 are arranged along the extending direction of the diffractive portion 20 and can detect sound waves.
The plurality of speakers 24 are arranged along the extending direction of the diffractive portion 20 and can each emit a sound wave.
The at least one control device 26 can adjust the sound wave emitted from each of the plurality of speakers 24 based on the sound wave detected by each of the plurality of reference microphones 22.

Here, according to the knowledge of the present inventors, there are two types of noise radiated from the vicinity of the upper end opening 8 a of the chimney 8.
Of these, the first noise is the noise that has propagated through the chimney 8, and this type of noise has a constant frequency. When this sound wave is emitted from the upper end opening 8a of the chimney 8, it propagates as noise to people on the ground.

  The second noise is noise caused by the fluid flowing out from the upper end opening 8 a of the chimney 8. As shown in FIG. 4, the fluid flowing out from the upper end opening 8a of the chimney 8 forms a region (pressure variation irregular region) A in which the pressure varies irregularly above the upper end opening 8a. Although a stable sound wave is not formed inside the pressure fluctuation irregular region A, an outward sound wave (noise wave N) is formed at the outer edge of the pressure fluctuation irregular region A. This sound wave propagates as noise to people on the ground. This type of second noise generally has a wider frequency distribution than the first noise.

  Therefore, in the chimney noise reduction system 1 (1a to 1o), the diffraction unit 20 is arranged away from the pressure fluctuation irregular region A generated above the upper end opening 8a of the chimney 8 by the fluid flowing out from the upper end opening 8a of the chimney 8. The noise wave N formed at the outer edge of the pressure fluctuation irregular region A and propagating toward the diffraction unit 20 is diffracted downward in cooperation with the sound insulation unit 21. . Note that the function of the sound insulation unit 21 is to block the propagation of the noise wave N immediately below the diffraction unit 20 and enable the formation of a diffracted wave outside the sound insulation unit 21. As long as it is possible to block the propagation of the noise wave N directly under the diffractive portion 20, the configuration of the sound insulating portion 21 is not particularly limited.

Each of the plurality of reference microphones 22 is disposed so as to be able to detect the noise wave N formed at the outer edge of the pressure fluctuation irregular region A, and each of the plurality of speakers 24 radiates each of the plurality of speakers 24. The sound wave (the muffled sound wave C) is disposed so as to spatially overlap the noise wave N formed at the outer edge of the pressure fluctuation irregular region A.
Further, the control device 26 radiates each of the plurality of speakers 24 such that the noise wave N diffracted downward by the diffraction unit 20 is canceled out by the silencer C radiated from each of the plurality of speakers 24. It is comprised so that the silencer C to be adjusted may be adjusted. The adjustment of the silencer C includes adjusting the frequency, phase and sound pressure of the silencer C.

  According to the chimney noise reduction system 1 (1a to 1o) having the above-described configuration, the control device 26 diffracts downward by the diffracting unit 20 by adjusting the silencer C emitted from each of the plurality of speakers 24. The generated noise wave N can be canceled by the silencer C. Thereby, noise reaching the ground from the upper end opening 8a of the chimney 8 can be reduced regardless of the frequency.

In particular, according to the chimney noise reduction system 1 (1a to 1o) having the above-described configuration, the diffracting unit 20 diffracts the noise wave N, so that the propagation direction of the diffracted noise wave N and the propagation direction of the silencer C Can be matched. For this reason, it is possible to superimpose the noise wave N and the silencer C having opposite phases over a wide spatial range, thereby reducing the noise reaching the ground.
In the chimney noise reduction system 1 (1a) shown in FIG. 4, the speaker 24 radiates sound waves upward, but the direction in which the speaker 24 emits sound waves is not limited to the upper side. .

In some embodiments, the diffraction unit 20 is disposed at a distance L1 of 200 mm or more and 2000 mm or less in the horizontal direction from the outer edge of the upper end opening 8a of the chimney 8 (see FIG. 2).
In some embodiments, one speaker 24 and one controller 26 are provided corresponding to one reference microphone 22, and one reference microphone 22, one speaker 24, and one controller corresponding to each other are provided. 26 constitutes one unit. A plurality of units are arranged along the extending direction of the diffractive portion 20.

In some embodiments, the chimney noise reduction system 1 further includes a plurality of error microphones (error microphones) 28, such as the chimney noise reduction systems 1b, 1c, and 1d shown in FIGS.
The plurality of error microphones 28 are arranged along the extending direction of the diffraction unit 20, and the noise wave N diffracted downward by the diffraction unit 20 is emitted from each of the plurality of speakers 24. And each can be detected.
Then, the at least one control device 26 uses the plurality of speakers 24 such that the noise wave N is canceled by the muffling C based on the noise wave N and the muffling C detected by each of the plurality of error microphones 28. The silencer C emitted from each can be adjusted.

  Thus, when the chimney noise reduction system 1 further includes the error microphone 28 as in the chimney noise reduction systems 1b, 1c, and 1d, it is radiated from each of the plurality of speakers 24 based on the detection result of the error microphone 28. The silencer C can be adjusted. As a result, even if the noise wave N formed at the outer edge of the pressure fluctuation irregular region A changes with time, the noise wave N diffracted downward by the diffractive portion 20 can be reliably obtained regardless of the frequency. Can be reduced.

  In some embodiments, one speaker 24, one control device 26 and one error microphone 28 are provided corresponding to one reference microphone 22, and one reference microphone 22 and one speaker corresponding to each other. 24, one control device 26 and one error microphone 28 constitute one unit. A plurality of units are arranged along the extending direction of the diffractive portion 20.

  In some embodiments, like the chimney noise reduction systems 1b and 1d shown in FIGS. 7 and 8, the control device 26 (26a and 26b) is constituted by an adaptive filter. That is, the control device 26 a includes a variable filter unit 30 and a coefficient calculation unit 32. Based on the noise wave detection signal detected by the reference microphone 22, the variable filter unit 30 generates an output signal for causing the speaker 24 to output the sound deadening, and outputs the generated output signal to the speaker 24. The coefficient calculation unit 32 uses the error microphone 28 based on the detection signal of the noise wave detected by the reference microphone 22 and the detection signal of the sound wave (the combined wave of the noise wave and the silenced wave) detected by the error microphone 28. The filter coefficient used to generate the output signal in the variable filter unit 30 is calculated so that the detection signal of the detected sound wave becomes small, and the calculated filter coefficient is output to the variable filter unit 30. The filter coefficient is repeatedly calculated and output until the detection signal of the sound wave detected by the error microphone 28 becomes small.

  In some embodiments, like the chimney noise reduction system 1b illustrated in FIG. 7, the control device 26 (26a) further includes a sound pressure setting unit 34 and a deviation calculation unit 36. The sound pressure setting unit 34 adjusts the sound pressure of the output signal of the variable filter unit 30, and the deviation calculation unit 36 calculates the deviation of the sound wave (noise wave and silenced wave) detected by the reference microphone 22. . Thus, according to the sound pressure setting unit 34 and the deviation calculation unit 36, it is possible to eliminate the influence when the reference microphone 22 detects the sound deadening.

Normally, the reference microphone 22 is arranged at the most upstream side in the propagation direction of the noise wave N, the speaker 24 is arranged downstream from the reference microphone 22, and the error microphone 28 is arranged downstream from the speaker 24. .
For example, the reference microphone 22 is disposed at a distance L2 of 150 mm or more and 1950 mm or less in the horizontal direction from the outer edge of the upper end opening 8a of the chimney 8 (see FIG. 2).

  In some embodiments, like the chimney noise reduction system 1 a shown in FIG. 9, the control device 26 (26 c) has a coefficient calculation unit 32 for automatically changing the filter coefficient of the variable filter unit 30. Not done. When the noise wave is constant, once the filter coefficient used in the variable filter unit 30 is set corresponding to the noise wave, it is not necessary to change the filter coefficient, and the coefficient calculation unit 32 can be omitted.

  In some embodiments, the chimney noise reduction system 1 includes a plurality of casings 40, such as the chimney noise reduction system 1b shown in FIG. Each of the plurality of casings 40 accommodates one speaker 24 and one control device 26 corresponding to the speaker 24, and one corresponding reference microphone 22 is attached to the outside. The casing 40 has an opening, and the speaker 24 faces the outside of the casing 40 through the opening. In this case, the casing 40 constitutes a housing for a unit constituted by one reference microphone 22, one speaker 24 and one control device 26.

  In some embodiments, the sound insulation 21 is constituted by at least one wall 50 as shown in FIGS. The wall 50 is supported by at least one support member 52 attached to the chimney 8, for example.

  In some embodiments, a plurality of reference microphones 22, a plurality of speakers 24, and optionally a plurality of error microphones 28 are placed on the wall 50, as shown in FIGS. 2-6 and FIGS. 10-24, respectively. It is attached directly or indirectly.

  In some embodiments, like the chimney noise reduction system 1b shown in FIG. 5, the upper edge of the wall 50 constitutes the diffractive portion 20 (20a). In some embodiments, like the chimney noise reduction system 1c shown in FIG. 6, the casing 40 is disposed on the wall 50, and the upper edge of the casing 40 forms the diffractive portion 20 (20b). That is, the diffractive portion 20 may be a part of the wall 50, or may be configured by a member different from the wall 50, such as the casing 40.

In some embodiments, like the chimney noise reduction systems 1a and 1e shown in FIGS. 3 and 10, respectively, the diffraction section 20 (20a and 20b), a plurality of reference microphones 22, a plurality of speakers 24, and as necessary. The plurality of error microphones 28 are arranged so as to surround the upper end opening 8a of the chimney 8 in the circumferential direction of the chimney 8 over the entire circumference.
As in the chimney noise reduction systems 1a and 1e, the diffracting section 20 (20a and 20b), a plurality of reference microphones 22, a plurality of speakers 24, and a plurality of error microphones 28 as necessary, are arranged in the circumferential direction of the chimney 8. 8 is arranged to surround the upper end opening 8a of the chimney 8 over the entire circumference, the noise reaching the ground from the upper end opening 8a of the chimney 8 can be reduced over the entire periphery of the chimney 8 regardless of the frequency. it can.

In some embodiments, like the chimney noise reduction system 1a shown in FIG. 3, the wall 50 is constituted by a cylindrical wall 50a. In some embodiments, like the chimney noise reduction system 1e shown in FIG. 10, the wall 50 is configured by a square tube-shaped wall 50b. In some embodiments, like the chimney noise reduction system 1l shown in FIG. 21, the wall 50 is constituted by a tapered tubular wall 50c. Moreover, the wall 50 may have an elliptical cylinder shape, and may have a polygonal rectangular tube shape whose cross section is other than a quadrangle.
In addition, according to the cylindrical wall 50c with a taper, the clearance gap between the chimney 8 and the sound insulation part 21 can be narrowed in the lower end side of the wall 50c compared with the case where there is no taper. Thereby, the propagation of the noise wave in the gap between the chimney 8 and the sound insulation part 21 can be blocked, and the noise reaching the ground can be further reduced regardless of the frequency.

  In some embodiments, the diffractive portion 20 (20 a, 20 b) extends continuously along the circumferential direction of the chimney 8. Note that the diffractive portion 20 (20a, 20b) continuously extends means that the diffractive portion 20 (20a, 20b) has a discontinuous portion having a length about the wavelength of the noise wave, such as a notch or a gap. Including the case of doing. If it is a discontinuous part having a length of about the wavelength of the noise wave, the influence on the noise reduction characteristics of the chimney noise reduction system 1 can be ignored.

In some embodiments, like the chimney noise reduction systems 1f to 1i and 1m shown in FIGS. 11 to 14 and 22, respectively, the diffraction section 20 (20a and 20b), the plurality of reference microphones 22, and the plurality of speakers. 24 and, if necessary, a plurality of error microphones 28 are arranged so as to face only a part of the upper end opening 8 a of the chimney 8 in the circumferential direction of the chimney 8.
As in the chimney noise reduction systems 1f to 1i, 1m, the diffraction unit 20, the plurality of reference microphones 22, the plurality of speakers 24, and the plurality of error microphones 28 as required are arranged at the upper end of the chimney 8 in the circumferential direction of the chimney 8. When arranged so as to face only a part of the opening 8a, the chimney in the direction in which the diffractive portion 20, the plurality of reference microphones 22, the plurality of speakers 24, and the plurality of error microphones 28 as necessary are arranged. The noise reaching the ground from the upper end opening 8a can be reduced regardless of the frequency.

In some embodiments, as shown in FIGS. 11, 13, 14, 16, and 17, the diffractive section 20, multiple reference microphones 22, multiple speakers 24, and multiple error microphones as needed. Each 28 is arranged on an arc. In this case, the wall 50 is constituted by at least one wall 50d having a divided cylindrical shape with a circular arc cross section.
In some embodiments, as illustrated in FIG. 12, the diffraction unit 20, the plurality of reference microphones 22, the plurality of speakers 24, and the plurality of error microphones 28 as necessary are arranged on a straight line. In this case, the wall 50 is constituted by at least one flat wall 50e.

In some embodiments, like the chimney noise reduction systems 1h and 1i shown in FIGS. 13 to 15, respectively, the diffraction unit 20, the plurality of reference microphones 22, the plurality of speakers 24, and a plurality of error microphones as necessary. 28 is rotatable in the circumferential direction of the chimney 8.
As in the chimney noise reduction systems 1h and 1i, when the diffraction unit 20, the plurality of reference microphones 22, the plurality of speakers 24, and the plurality of error microphones 28 are rotatable in the circumferential direction of the chimney 8, the diffraction unit 20, By changing the positions of the plurality of reference microphones 22, the plurality of speakers 24, and the plurality of error microphones 28 as necessary, the noise that reaches the ground from the upper end opening 8 a of the chimney 8 can be changed to a frequency in any direction. Regardless, it can be reduced.
For example, as shown in FIG. 15, the wall 50 (50d, 50e) can be rotated by attaching the support member 52 to the chimney 8 via the rotation mechanism 54, whereby the diffraction section 20 and the plurality of references are made. The microphone 22, the plurality of speakers 24, and the plurality of error microphones 28 as necessary can be rotated in the circumferential direction of the chimney 8.

In some embodiments, like the chimney noise reduction system 1 i shown in FIGS. 14 and 15, the length (full length) of the diffraction section 20 in the circumferential direction of the chimney 8 is variable.
When the length of the diffractive portion 20 (20a, 20b) in the circumferential direction of the chimney 8 is variable as in the chimney noise reduction system 1i, the length of the diffractive portion 20 (20a, 20b) in the circumferential direction of the chimney 8 By changing the height, noise reaching the ground from the upper end opening 8a of the chimney 8 can be reduced in an arbitrary range in the circumferential direction of the chimney 8 regardless of the frequency.

  For example, one or both of the two walls 50 (50d) having different radii are attached to the chimney 8 via the rotation mechanism 54, and one of the two walls 50 (50d) as shown in FIG. Or the length (full length) of the diffraction part 20 (20a, 20b) can be changed by rotating both.

In some embodiments, like the chimney noise reduction system 1j shown in FIGS. 16 to 18, the distance provided between the upper end opening 8a of the chimney 8 and the diffraction part 20 is variable.
Roughly speaking, as shown in FIG. 4, the noise wave N is formed at the outer edge of the pressure fluctuation irregular region A, but the formation position of the noise wave N differs depending on the frequency. By utilizing this, the frequency of the noise wave N to be reduced can be changed by changing the distance provided between the upper end opening 8a of the chimney 8 and the diffractive portion 20 (20a, 20b). The frequency characteristics required for the noise reduction system 1 can be easily realized.

  For example, at least one wall 50 (50d) is attached to the support member 52 or the chimney 8 via the horizontal reciprocating mechanism 56 as shown in FIG. 8, the distance between the upper end opening 8a and the diffractive portion 20 (20a, 20b) can be changed.

In some embodiments, like the chimney noise reduction system 1j shown in FIGS. 16 to 18, the horizontal distance between the chimney 8 and the sound insulation part 21 is variable.
According to the above configuration, by narrowing the gap between the chimney 8 and the sound insulation part 21, the propagation of noise waves in the gap between the chimney 8 and the sound insulation part 21 is blocked, and the noise reaching the ground is affected by the frequency. This can be further reduced.

In some embodiments, as in the chimney noise reduction system 1k shown in FIGS. 19 and 20, the vertical position of the diffraction section 20 (20a, 20b) is variable.
In the vicinity of the upper end opening 8a of the chimney 8, the propagation direction of noise waves may be bent by the flow of wind. In this regard, if the vertical position of the diffraction unit 20 (20a, 20b) is variable, the height of the diffraction unit 20 (20a, 20b) can be adjusted according to the propagation direction of the noise wave N, and the ground Can be reduced regardless of the wind flow in the sky.

  For example, at least one wall 50 (50a, 50b, 50c, 50d, 50e) is attached to the support member 52 or the chimney 8 via the vertical reciprocating mechanism 58 as shown in FIGS. By moving one wall 50 (50a, 50b, 50c, 50d, 50e) in the vertical direction, the vertical position of the diffractive portion 20 (20a, 20b) can be changed.

In some embodiments, like the chimney noise reduction system 1k shown in FIG. 20, the diffractive portion 20 (20a, 20b) can be disposed above the upper end opening 8a of the chimney 8 in the vertical direction. .
In the vicinity of the upper end opening 8a of the chimney 8, the propagation direction of noise waves may be bent by the flow of wind. For this reason, if the upper end opening 8a of the chimney 8 and the height of the diffractive portion 20 are the same, the noise wave may propagate to the ground beyond the diffractive portion 20 without being diffracted. In this respect, by arranging the diffractive portion 20 above the upper end opening 8a of the chimney 8, it is possible to prevent the noise wave from exceeding the diffracting portion 20 without being diffracted, and the noise reaching the ground can be It can be reduced regardless of the flow.

In some embodiments, like the chimney noise reduction system 1k shown in FIGS. 19 and 20, the sound insulation part 21 has a variable length in the vertical direction.
When the sound insulation part 21 has a variable length in the vertical direction, by adjusting the length of the sound insulation part 21 in the vertical direction, the noise insulation part 21 directly blocks the propagation of noise waves and reaches the ground. Can be further reduced regardless of the frequency.

  For example, the length of the sound insulation part 21 in the vertical direction can be changed by the following configuration. First, the sound insulating portion 21 is configured by a plurality of walls 50 (50a, 50b, 50c, 50d, 50e) provided to overlap each other. Then, at least one of the plurality of walls 50 (50a, 50b, 50c, 50d, 50e) is attached to the support member 52 or the chimney 8 via the vertical reciprocating mechanism 58. According to such a configuration, as shown in FIGS. 19 and 20, by moving at least one wall 50 (50a, 50b, 50c, 50d, 50e) in the vertical direction, the sound insulating portion 21 in the vertical direction. The length of can be changed.

In some embodiments, as shown in FIG. 22, as in the chimney noise reduction system 1 m, the sound insulation part 21 can swing so that the distance between the lower end side of the sound insulation part 21 and the chimney 8 changes. It is.
By swinging the sound insulation portion 21 so that the distance between the lower end side of the sound insulation portion 21 and the chimney 8 is shortened, the propagation of noise waves in the gap between the chimney 8 and the sound insulation portion 21 is interrupted, and the ground The noise that reaches can be further reduced regardless of the frequency.
For example, as illustrated in FIG. 22, the sound insulating portion 21 is configured by a plurality of walls 50 (50e) connected via the swing mechanism 60, and the lower wall 50 ( The distance between the lower end side of the sound insulation part 21 and the chimney 8 can be shortened by swinging 50e).

In some embodiments, like the chimney noise reduction system 1n shown in FIG. 23, the chimney noise reduction system 1 further includes a sound absorbing unit 62 disposed between the sound insulation unit 21 and the chimney 8.
By arranging the sound absorption part 62 between the sound insulation part 21 and the chimney 8, noise waves propagating through the gap between the chimney 8 and the sound insulation part 21 can be reduced, and noise reaching the ground can be reduced regardless of the frequency. Can be further reduced.

In some embodiments, the sound absorbing portion 62 covers at least part of the inner surface of the wall 50 (50a, 50b, 50c, 50d, 50e) with respect to the wall 50 (50a, 50b, 50c, 50d, 50e). Attached to.
By attaching the sound absorbing portion 62 so as to cover at least a part of the inner surface of the wall 50 (50a, 50b, 50c, 50d, 50e), reflection of noise waves at the sound insulating portion 21 can be suppressed and reach the ground. Noise can be further reduced regardless of frequency.
For example, the sound absorbing part 62 is configured by a member having irregularities on the surface thereof such as a porous plate.

In some embodiments, like the chimney noise reduction system 1o shown in FIG. 24, the chimney 8 has a stepped portion 64 that protrudes below the upper end opening 8a and laterally from the upper end opening 8a. The sound insulation part 21 is directly or indirectly attached to the step part 64.
By attaching the sound insulating part 21 to the step part 64 of the chimney 8, the sound insulating part 21 can be arranged with a simple configuration.
For example, the step portion 64 is constituted by an outer wall of a silencer 66 attached to the chimney 8. The silencer 66 has a cavity 68 that communicates with the inside of the chimney 8 through a communication hole (not shown), and is configured to reduce sound waves having a specific frequency that propagates inside the chimney 8.

  In some embodiments, the gap (space) between the chimney 8 and the sound insulation part 21 is opened in addition to the upper part, and does not constitute an acoustic tube or a resonator.

FIG. 25 is a flowchart showing a schematic procedure of a setting method of the chimney noise reduction system 1 (1a) according to the embodiment of the present invention.
As shown in FIG. 25, the setting method of the chimney noise reduction system includes the error microphone placement step S10 for placing the error microphone 28, the control device setting step S12 for adjusting the setting of the control device 26 (26c), and the error microphone. Error microphone removing step S14 for removing 28.

In the error microphone arrangement step S <b> 10, noise waves diffracted downward by the diffraction unit 20 along the extending direction of the diffraction unit 20 can be detected together with sound waves emitted from each of the plurality of speakers 24. A plurality of error microphones 28 are arranged.
The position where the error microphone 28 is disposed is not particularly limited as long as it is downstream of the diffraction unit 20 in the direction of propagation of sound waves.

  In the control device setting step S12, the setting of at least one control device 26 (26c) is adjusted based on the sound wave (the combined wave of the noise wave and the silenced wave) detected by each of the plurality of error microphones 28. Note that the setting of the control device 26 specifically adjusts the filter coefficient of the variable filter unit 30.

In the error microphone removal step S14, the plurality of error microphones 28 are removed after the control device setting step S12.
If there is no particular change in the flow of fluid discharged from the chimney 8, once the control device 26 (26c) is set, there is no need to change it later. Therefore, the configuration of the remaining chimney noise reduction system 1 (1a) can be simplified by arranging the error microphone 28 once and then removing it.

The present invention is not limited to the above-described embodiments, and includes forms obtained by changing the above-described embodiments and forms obtained by combining these forms.
For example, the planar shapes of the chimney 8 and the upper end opening 8a are not particularly limited, and may be a quadrilateral shape in addition to a circular shape. When the planar shape of the chimney 8 or the upper end opening 8a is not circular, the circumferential direction of the chimney 8 or the upper end opening 8a refers to the direction around the axis of the chimney 8 or the upper end opening 8a.

DESCRIPTION OF SYMBOLS 1 (1a-1o) Chimney noise reduction system 2 Gas turbine power generation system 3 Gas turbine 4 Generator 6 Exhaust gas treatment device 8 Chimney 8a Upper end opening 10 Compressor 12 Combustor 14 Turbine 20 (20a, 20b) Diffraction part 21 Sound insulation part 22 Reference microphone 24 Speaker 26 (26a, 26b, 26c) Control device 28 Error microphone 30 Variable filter unit 32 Coefficient calculation unit 34 Sound pressure setting unit 36 Deviation calculation unit 40 Casing 50 (50a to 50e) Wall 52 Support member 54 Rotating mechanism 56 Horizontal reciprocating mechanism (radial reciprocating mechanism)
58 Vertical reciprocating mechanism 60 Oscillating mechanism 62 Sound absorbing part 64 Step part 66 Silencer 68 Cavity

Claims (14)

A diffractive portion that is arranged at a distance from the upper end opening of the chimney in the radial direction of the upper end opening and extends in a horizontal direction intersecting the radial direction,
A sound insulation part extending downward from the diffraction part;
A plurality of reference microphones arranged along the extending direction of the diffractive portion, each capable of detecting sound waves;
A plurality of speakers arranged along the extending direction of the diffractive portion, each capable of emitting sound waves;
At least one control device capable of adjusting sound waves radiated by each of the plurality of speakers based on sound waves detected by each of the plurality of reference microphones;
With
The diffractive part is disposed away from an irregular region where the pressure fluctuation generated above the upper end opening of the chimney is caused by the fluid flowing out from the upper end opening of the chimney, and is formed at the outer edge of the irregular region. is the noisy sound wave that propagates toward the diffractive portion, the sound insulation part and in cooperation are adapted to diffract downward is,
Each of the plurality of reference microphones, the noise wave formed by the outer edge of the region is detectably arranged,
Each of said plurality of speakers, sound waves each of said plurality of speakers is radiated is disposed so as to overlap with the noise wave formed by the outer edge of said region,
The control device adjusts the sound wave emitted from each of the plurality of speakers so that the sound wave emitted from each of the plurality of speakers cancels out the noise wave diffracted downward by the diffraction unit. is configured to,
The diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged so as to face only a part of the upper end opening of the chimney in the circumferential direction of the chimney, and the diffraction unit, the plurality of reference microphones, and The chimney noise reduction system , wherein the plurality of speakers are rotatable in a circumferential direction of the chimney. A diffractive portion that is arranged at a distance from the upper end opening of the chimney in the radial direction of the upper end opening and extends in a horizontal direction intersecting the radial direction,
A sound insulation part extending downward from the diffraction part;
A plurality of reference microphones arranged along the extending direction of the diffractive portion, each capable of detecting sound waves;
A plurality of speakers arranged along the extending direction of the diffractive portion, each capable of emitting sound waves;
At least one control device capable of adjusting sound waves radiated by each of the plurality of speakers based on sound waves detected by each of the plurality of reference microphones;
With
The diffractive part is disposed away from an irregular region where the pressure fluctuation generated above the upper end opening of the chimney is caused by the fluid flowing out from the upper end opening of the chimney, and is formed at the outer edge of the irregular region. is the noisy sound wave that propagates toward the diffractive portion, the sound insulation part and in cooperation are adapted to diffract downward is,
Each of the plurality of reference microphones, the noise wave formed by the outer edge of the region is detectably arranged,
Each of said plurality of speakers, sound waves each of said plurality of speakers is radiated is disposed so as to overlap with the noise wave formed by the outer edge of said region,
The control device adjusts the sound wave emitted from each of the plurality of speakers so that the sound wave emitted from each of the plurality of speakers cancels out the noise wave diffracted downward by the diffraction unit. is configured to,
The diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged so as to face only a part of the upper end opening of the chimney in the circumferential direction of the chimney, and the diffraction unit in the circumferential direction of the chimney The chimney noise reduction system, characterized in that its length is variable . A plurality of error microphones arranged along the extending direction of the diffractive part and capable of detecting the noise wave diffracted downward by the diffractive part together with the sound wave radiated from each of the plurality of speakers Further comprising
The at least one control device is capable of adjusting the sound wave radiated from each of the plurality of speakers based on the noise wave and the sound wave detected by each of the plurality of error microphones. The chimney noise reduction system according to claim 1 or 2 . The chimney noise reduction system according to claim 1 or 3 , wherein the length of the diffraction part in the circumferential direction of the chimney is variable. The chimney noise reduction system according to any one of claims 1 to 4 , wherein the distance provided between the upper end opening of the chimney and the diffraction part is variable. The chimney noise reduction system according to any one of claims 1 to 5 , wherein a position of the diffraction unit in a vertical direction is variable. The chimney noise reduction system according to claim 6 , wherein the diffractive portion can be arranged above the upper end opening of the chimney in the vertical direction. The chimney noise reduction system according to any one of claims 1 to 7 , wherein the sound insulation part has a variable length in the vertical direction. The chimney noise reduction system according to any one of claims 1 to 8 , wherein a distance between the chimney and the sound insulation unit is variable. The chimney noise reduction system according to claim 9 , wherein the sound insulation unit is swingable so that a distance between a lower end side of the sound insulation unit and the chimney changes. The chimney noise reduction system according to any one of claims 1 to 10 , further comprising a sound absorption unit disposed between the sound insulation unit and the chimney. The chimney has a step portion that protrudes laterally from the upper end opening, below the upper end opening,
The chimney noise reduction system according to any one of claims 1 to 11 , wherein the sound insulation portion is attached to the stepped portion. A diffractive portion that is disposed at a distance from the upper end opening of the chimney in the radial direction of the upper end opening and extends along a horizontal direction intersecting the radial direction;
A sound insulation part extending downward from the diffraction part;
A plurality of reference microphones arranged along the extending direction of the diffractive portion, each capable of detecting sound waves;
A plurality of speakers arranged along the extending direction of the diffractive portion, each capable of emitting sound waves;
At least one control device capable of adjusting sound waves radiated by each of the plurality of speakers based on sound waves detected by each of the plurality of reference microphones;
With
The diffractive part is disposed away from an irregular region where the pressure fluctuation generated above the upper end opening of the chimney is caused by the fluid flowing out from the upper end opening of the chimney, and is formed at the outer edge of the irregular region. is the noisy sound wave that propagates toward the diffractive portion, the sound insulation part and in cooperation are adapted to diffract downward is,
Each of the plurality of reference microphones, the noise wave formed by the outer edge of the region is detectably arranged,
Each of said plurality of speakers, sound waves each of said plurality of speakers is radiated is disposed so as to overlap with the noise wave formed by the outer edge of said region,
The control device adjusts the sound wave emitted from each of the plurality of speakers so that the sound wave emitted from each of the plurality of speakers cancels out the noise wave diffracted downward by the diffraction unit. is configured to,
The diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged so as to face only a part of the upper end opening of the chimney in the circumferential direction of the chimney, and the diffraction unit, the plurality of reference microphones, and The plurality of speakers is a method for adjusting a chimney noise reduction system that is rotatable in a circumferential direction of the chimney,
A plurality of error microphones capable of detecting the noise wave diffracted downward by the diffraction unit along with the sound wave radiated from each of the plurality of speakers is disposed along the extending direction of the diffraction unit. And
Adjusting the setting of the at least one control device based on the noise wave and the sound wave detected by each of the plurality of error microphones;
A method for adjusting a chimney noise reduction system, comprising: removing the plurality of error microphones after adjusting the setting of the at least one control device. A diffractive portion that is disposed at a distance from the upper end opening of the chimney in the radial direction of the upper end opening and extends along a horizontal direction intersecting the radial direction;
A sound insulation part extending downward from the diffraction part;
A plurality of reference microphones arranged along the extending direction of the diffractive portion, each capable of detecting sound waves;
A plurality of speakers arranged along the extending direction of the diffractive portion, each capable of emitting sound waves;
At least one control device capable of adjusting sound waves radiated by each of the plurality of speakers based on sound waves detected by each of the plurality of reference microphones;
With
The diffractive part is disposed away from an irregular region where the pressure fluctuation generated above the upper end opening of the chimney is caused by the fluid flowing out from the upper end opening of the chimney, and is formed at the outer edge of the irregular region. is the noisy sound wave that propagates toward the diffractive portion, the sound insulation part and in cooperation are adapted to diffract downward is,
Each of the plurality of reference microphones, the noise wave formed by the outer edge of the region is detectably arranged,
Each of said plurality of speakers, sound waves each of said plurality of speakers is radiated is disposed so as to overlap with the noise wave formed by the outer edge of said region,
The control device adjusts the sound wave emitted from each of the plurality of speakers so that the sound wave emitted from each of the plurality of speakers cancels out the noise wave diffracted downward by the diffraction unit. is configured to,
The diffraction unit, the plurality of reference microphones, and the plurality of speakers are arranged so as to face only a part of the upper end opening of the chimney in the circumferential direction of the chimney, and the diffraction unit in the circumferential direction of the chimney Is a method of adjusting a chimney noise reduction system , the length of which is variable ,
A plurality of error microphones capable of detecting the noise wave diffracted downward by the diffraction unit along with the sound wave radiated from each of the plurality of speakers is disposed along the extending direction of the diffraction unit. And
Adjusting the setting of the at least one control device based on the noise wave and the sound wave detected by each of the plurality of error microphones;
A method for adjusting a chimney noise reduction system, comprising: removing the plurality of error microphones after adjusting the setting of the at least one control device.

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