JP7257157B2 - Acoustic dampers, combustors and gas turbines - Google Patents

Description

The present invention relates to acoustic dampers, combustors and gas turbines.

Conventionally, as a source of vibration, for example, a technique related to a device for damping combustion vibration in a combustor of a gas turbine is known. For example, in US Pat. No. 5,400,008, a plurality of quarter-wave resonators coupled to an air supply, a fuel supply, and a diluent supply upstream of a combustor, and a controller for adjusting the resonators are disclosed. A gas turbine system is disclosed comprising: In this gas turbine system, the quarter-wave resonator is a variable-shape resonator, and the pressure sensor detects the pressure oscillation in the combustor, and the shape of the variable-shape resonator is adjusted based on the detected pressure. By adjusting, the vibration of the desired frequency is attenuated.

JP 2011-52954 A

Since the tuning frequency is determined by the length of the wavelength tube of the acoustic damper in order to aim at damping the vibration of the desired frequency, a variable-shape acoustic damper, such as the gas turbine system described in Patent Document 1, is used. The structure of the acoustic damper tends to be complicated, such as using a damper. Furthermore, the volume of the acoustic damper tends to be large in order to dampen the vibration satisfactorily. As a result, there tends to be a shortage of space for mounting the acoustic damper. Therefore, a compact acoustic damper with a simpler configuration is desired.

SUMMARY OF THE INVENTION It is an object of the present invention to satisfactorily attenuate the vibration of a vibration source by using a compact acoustic damper with a simpler structure.

In order to solve the above-described problems and achieve the object, the present invention provides an acoustic damper body fixed to a vibration source and forming a passage for taking in air vibrations generated by the vibration source, and a predetermined spring constant. and a diaphragm attached to the outer surface of the acoustic damper body.

With this configuration, by attaching a diaphragm having a predetermined spring constant to the outer surface of the housing, the vibration of the housing can be absorbed by the diaphragm, and the acoustic boundary condition of the acoustic damper can be changed. As a result, the eigenvalue of the resonance frequency of the acoustic damper can be changed and the sound pressure level can be reduced, so that it is possible to reduce the size of the acoustic damper aiming at damping vibrations at the same resonance frequency. Therefore, according to the present invention, it is possible to satisfactorily attenuate the vibration of the vibration source with a compact acoustic damper with a simpler configuration.

Also, the predetermined spring constant of the diaphragm is preferably 10 N/mm or more and 100 N/mm or less. This configuration allows the diaphragm 50 to deform under the action of a relatively small load. That is, the diaphragm can be deformed to absorb minute vibrations.

Moreover, it is preferable that the diaphragm is a space-filling solid having a plurality of cavities therein. With this configuration, a diaphragm having a predetermined spring constant can be easily obtained.

Moreover, it is preferable that the space-filling solid has slits between partition walls that separate the plurality of cavities. With this configuration, the spring constant of the diaphragm can be made smaller, and the diaphragm can be easily deformed in response to minute vibrations.

Further, in the space-filling solid, it is preferable that the partition wall is curved along the load acting direction. With this configuration, the spring constant of the diaphragm can be made smaller, and the diaphragm can be easily deformed in response to minute vibrations.

Moreover, it is preferable that the diaphragm is a truncated conical spring. With this configuration, the spring constant of the diaphragm can be easily adjusted, and the configuration of the diaphragm can be simplified.

Moreover, it is preferable that the diaphragm is a spring having a truncated quadrangular pyramid shape. With this configuration, the spring constant of the diaphragm can be easily adjusted, and the configuration of the diaphragm can be simplified.

Moreover, it is preferable that the diaphragm is formed by stacking a plurality of the springs continuously. With this configuration, the spring constant of the diaphragm can be made smaller, and the diaphragm can be easily deformed in response to minute vibrations.

In order to solve the above-described problems and achieve the object, a combustor according to the present invention attaches the acoustic damper to the outer surface of the combustion tube, and the air vibration of the combustion gas flowing through the combustion tube is transmitted to the acoustic damper. It is characterized by inflow.

With this configuration, the vibration of the combustor can be favorably damped with a simpler configuration and a smaller acoustic damper.

In order to solve the above-described problems and achieve the object, a gas turbine according to the present invention is characterized by comprising the combustor described above.

With this configuration, the vibration of the combustor can be favorably damped with a simpler configuration and a smaller acoustic damper.

FIG. 1 is a schematic configuration diagram of a gas turbine according to the first embodiment. FIG. 2 is a side view of the combustor according to the first embodiment. FIG. 3 is an explanatory diagram schematically showing an acoustic damper to which a diaphragm is attached. FIG. 4 is an explanatory diagram showing an example of the load-displacement characteristics of the diaphragm. FIG. 5 is an explanatory diagram showing an example of analysis results of the relationship between the resonance frequency and the sound pressure level in the acoustic damper according to the embodiment. FIG. 6 is an explanatory diagram showing an example of analysis results of pressure strain characteristics for each specific example of the diaphragm according to the first embodiment. FIG. 7 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 8 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 9 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 10 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 11 is an explanatory diagram showing a concrete example of the diaphragm according to the first embodiment. FIG. 12 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 13 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 14 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 15 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 16 is an explanatory diagram showing a specific example of the diaphragm according to the first embodiment. FIG. 17 is an explanatory diagram showing a first modification of the diaphragm of the first embodiment. FIG. 18 is an explanatory diagram showing pressure strain characteristics of the diaphragm of the first modified example. FIG. 19 is an explanatory diagram showing a second modification of the diaphragm of the first embodiment. FIG. 20 is an explanatory diagram showing pressure strain characteristics of the diaphragm of the second modification. FIG. 21 is an explanatory diagram showing a specific example of the diaphragm according to the second embodiment. FIG. 22 is an explanatory diagram showing a specific example of the diaphragm according to the second embodiment. FIG. 23 is an explanatory diagram showing a specific example of the diaphragm according to the second embodiment. FIG. 24 is an explanatory diagram showing a specific example of the diaphragm according to the second embodiment. FIG. 25 is an explanatory diagram showing an example of analysis results of pressure strain characteristics of each diaphragm according to the second embodiment.

EMBODIMENT OF THE INVENTION Below, embodiment of the acoustic damper, combustor, and gas turbine concerning this invention is described in detail based on drawing. In addition, this invention is not limited by this embodiment.

[First embodiment]
FIG. 1 is a schematic configuration diagram of a gas turbine according to the first embodiment. As shown in FIG. 1, the gas turbine 100 includes a compressor 11, a combustor 12, a turbine 13, and an exhaust chamber 14. The compressor 11 is connected to a generator (not shown). The compressor 11 has an air intake port 15 for taking in air, and a plurality of stator vanes 17 and rotor vanes 18 are alternately arranged in a compressor casing 16 . The combustor 12 supplies fuel to the compressed air compressed by the compressor 11 and ignites it with a burner so that the fuel can be combusted. The turbine 13 has a plurality of stationary blades 21 and moving blades 22 alternately arranged in a turbine casing 20 . The exhaust chamber 14 has an exhaust diffuser 23 that is continuous with the turbine 13 . A rotor 24 is positioned so as to pass through the center of the compressor 11, the combustor 12, the turbine 13, and the exhaust chamber 14, and the end on the compressor 11 side is rotatably supported by a bearing 25. On the other hand, the end portion on the exhaust chamber 14 side is rotatably supported by a bearing portion 26 . A plurality of disk plates are fixed to the rotor 24, the moving blades 18 and 22 are connected, and the drive shaft of the generator (not shown) is connected to the end on the compressor 11 side.

Therefore, the air taken in from the air intake port 15 of the compressor 11 passes through the plurality of stationary blades 17 and rotor blades 18 and is compressed to become high-temperature and high-pressure compressed air. Combustion occurs when a predetermined fuel is supplied to the compressed air. High-temperature, high-pressure combustion gas, which is a working fluid generated in the combustor 12, passes through a plurality of stationary blades 21 and moving blades 22 that constitute the turbine 13, thereby driving and rotating a rotor 24. While driving the generator connected to 24, the exhaust gas is converted to static pressure by the exhaust diffuser 23 in the exhaust chamber 14 and then released to the atmosphere.

FIG. 2 is a side view of the combustor according to the first embodiment. The combustor 12 has an inner cylinder 32 supported inside a vehicle interior housing 30 and an outer cylinder 31 , and a transition piece 33 as a combustion cylinder is connected to the tip of the inner cylinder 32 .

The outer cylinder 31 is fastened to the vehicle interior housing 30 . The inner cylinder 32 is provided within the outer cylinder 31 with a gap from the outer cylinder 31 , and a pilot nozzle 35 is arranged along the axial direction, which is the extending direction of the combustor axis S, at the center of the inner cylinder 32 . is set. A plurality of main nozzles 36 are arranged in parallel with the combustor axis S so as to surround the pilot nozzles 35 along the circumferential direction on the inner peripheral surface of the inner cylinder 32 . The transition piece 33 has a cylindrical base end that is connected to the tip end of the inner cylinder 32 , bends and deforms with a cross-sectional area decreasing toward the tip side, and has a substantially rectangular tip shape to form a turbine. 13 , and is fastened to the vehicle interior housing 30 via a gusset 37 . The transition piece 33 has an inner side configured as a combustion chamber. The interior of the vehicle interior housing 30 is formed as a vehicle interior 38 , and the transition piece 33 is provided in the vehicle interior 38 .

In such a combustor 12 , high-temperature, high-pressure compressed air from the compressor 11 flows into the inner cylinder 32 from the base end side of the inner cylinder 32 through the casing 38 . This compressed air is guided to pilot nozzle 35 and main nozzle 36 . Then, the compressed air is mixed with the fuel injected from the main nozzle 36 and flows into the transition piece 33 as a premixed gas. The compressed air is mixed with fuel injected from the pilot nozzle 35 , ignited by a seed flame (not shown), combusted, and jetted into the transition piece 33 as combustion gas. At this time, part of the combustion gas is jetted into the transition piece 33 with flame so as to diffuse to the surroundings, thereby igniting and burning the premixed air that has flowed into the transition piece 33 from each main nozzle 36. . That is, the diffusion flame of the pilot fuel injected from the pilot nozzle 35 can hold the flame for stable combustion of the lean premixed fuel from the main nozzle 36 . In addition, by premixing the fuel by the main nozzle 36, the fuel concentration can be made uniform, thereby reducing NOx. The combustion gas is then supplied to the turbine 13 through the transition piece 33 .

The combustor 12 of the gas turbine 100 described above generates vibration (combustion vibration) when fuel is burned. This combustion oscillation causes noise and vibration during operation of the gas turbine 100 . Therefore, the side branch type acoustic damper 1 is provided for the combustor 12 (transition piece 33) as a vibration source through which the combustion gas flows.

The acoustic damper 1 is provided on the outer surface of the combustor 12 on the base end side of the transition piece 33, as shown in FIG. The acoustic damper 1 has a housing 2 as an acoustic damper main body extending along the axial direction of the transition piece 33, which is the direction in which the combustor axis S extends, outside the transition piece 33 of the combustor 12 as a vibration source. are doing. The housing 2 is formed in a straight pipe shape and adhered to the outer surface of the transition piece 33 . A housing 2 as an acoustic damper body is a so-called quarter-wave tube.

The acoustic damper 1 has a passage 3 forming an acoustic portion inside a housing 2 . The passage 3 is formed in a continuous manner, and one end is configured as an inlet (not shown) for taking in air vibrations generated by the vibration source. The inlet is provided so as to open toward the outer surface of the transition piece 33 . The transition piece 33 has a plurality of small through-holes (not shown) through which air vibrations (pressure waves) caused by combustion vibrations inside pass through to the outside. Air vibrations are introduced into the passage 3 from the inlet through the holes. In addition, the other end of the passage 3 is configured as a terminal end (not shown) that blocks the downstream side of the propagation of air vibrations and acts as a resistance to the air vibrations.

In the acoustic damper 1, when fuel gas flows through the transition piece 33, air vibrations (pressure waves) due to combustion oscillations of the combustion gas pass through the through holes of the transition piece 33 and are taken into the passage 3 of the acoustic section. . Then, in the passage 3, the air vibration propagated between the inlet and the end thereof resonates, and pressure fluctuations in the combustor 12 are damped.

In the first embodiment, the acoustic damper 1 has a diaphragm 50 . FIG. 3 is an explanatory diagram schematically showing an acoustic damper to which a diaphragm is attached, and FIG. 4 is an explanatory diagram showing an example of load displacement characteristics of the diaphragm. In this embodiment, the diaphragm 50 is fixed to the surface of the housing 2 opposite to the side in contact with the transition piece 33 . Note that the diaphragm 50 may be provided on any surface of the housing 2 other than the surface in contact with the transition piece 33 . Moreover, the diaphragm 50 may be provided so as to cover the entire surface of the housing 2 to which the diaphragm 50 is fixed, or may be provided so as to cover a part thereof.

The diaphragm 50 is made of an elastically deformable material, and exhibits nonlinear load-displacement characteristics, as shown in FIG. In other words, the diaphragm 50 has a spring constant exhibiting nonlinear characteristics. As shown in FIG. 4, the spring constant of diaphragm 50 deforms relatively greatly in region A where the initial load acts. That is, the spring constant of diaphragm 50 in region A is a relatively large value. Here, the initial load is the load acting on the diaphragm 50 due to the differential pressure between the inside and outside of the combustor 12 . After that, in a region B where a predetermined load larger than the initial load acts, the diaphragm 50 has a characteristic that the amount of displacement with respect to the load becomes gentler than in the region A. That is, the spring constant of diaphragm 50 in region B is smaller than the spring constant of diaphragm 50 in region A. FIG. The spring constant of diaphragm 50 in region B is 10 N/mm or more and 100 N/mm or less. It should be noted that the diaphragm 50 has a spring constant similar to that of the region A in the region C where a larger load than in the region B acts. The spring constant in region C is not limited to this, and may be approximately the same as in region B. The non-linear characteristics of the spring constant of the diaphragm 50 can be adjusted by, for example, the Young's modulus, density, plate thickness, and internal shape (shape of cavity described later) of the diaphragm 50 .

By attaching such a diaphragm 50 to the outer surface of the acoustic damper 1, a virtual vibration absorbing structure having springs and dampers is formed outside the acoustic damper 1, as shown in FIG. Become. Thereby, when air vibration from the combustor 12 resonates in the acoustic damper 1 , the diaphragm 50 serves as an acoustic impedance boundary, and the acoustic boundary condition of the acoustic damper 1 can be changed. That is, by absorbing the vibration by the diaphragm 50, the eigenvalue of the resonance frequency of the acoustic damper 1 can be changed, and the sound pressure level at the resonance frequency can be reduced.

FIG. 5 is an explanatory diagram showing an example of analysis results of the relationship between the resonance frequency and the sound pressure level in the acoustic damper according to the embodiment. In FIG. 5, the solid line indicates the relationship between the resonance frequency and the sound pressure level of the acoustic damper 1, and the dashed line indicates the relationship between the resonance frequency and the sound pressure level of an acoustic damper that does not have the diaphragm 50 as a comparative example. ing. As shown, in the acoustic damper of the comparative example, the sound pressure level peaks at point P1, which is the resonance frequency. On the other hand, in the acoustic damper 1 of the embodiment, the two points P2 and P3 become resonance frequencies due to the vibration absorption structure by the diaphragm 50, and the sound pressure level peaks at these points P2 and P3 are smaller than at the point P1. . Thus, the acoustic damper 1 can lower the acoustic level at the resonance frequency compared to the acoustic damper of the comparative example. In other words, the size of the acoustic damper 1 can be made smaller, ie the length of the quarter-wave tube formed by the housing 2 can be shortened when damping vibrations in the same frequency band. In this embodiment, the size of the acoustic damper 1 (the length of the quarter-wave tube) can be approximately half that of the comparative example.

Further, as described above, the diaphragm 50 has a load displacement characteristic, that is, a nonlinear characteristic of the spring constant. becomes gradual. As a result, when vibration is transmitted through the acoustic damper 1 due to the combustion vibration of the combustor 12 in a state where the vibration plate 50 receives an initial load due to the differential pressure between the inside and outside of the combustor 12, the diaphragm 50 receives a very small amount of vibration. It will be deformed by a small load due to vibration. As a result, it is possible to deform the diaphragm 50 corresponding to minute vibrations, absorb the vibrations satisfactorily, and reduce the sound pressure level at the resonance frequency as described above.

Next, a specific configuration of diaphragm 50 will be described with reference to FIGS. 6 to 16. FIG. FIG. 6 is an explanatory diagram showing an example of analysis results of pressure strain characteristics for each specific example of the diaphragm according to the first embodiment, and FIGS. 7 to 16 are specific examples of the diaphragm according to the first embodiment. It is an explanatory view showing . FIG. 6 shows pressure strain characteristics in region B of FIG. 4 (the same applies to FIGS. 18, 20, and 25 described later). Each diaphragm 50 shown in FIGS. 7 to 16 is a space-filling solid (space-filling polyhedron) in which a plurality of cavities are formed.

Hereinafter, the diaphragm 50 shown in FIGS. 7 and 8 is referred to as "diaphragm 50A", the diaphragm 50 illustrated in FIGS. 9 and 10 is referred to as "diaphragm 50B", and the diaphragm 50 illustrated in FIGS. is called "diaphragm 50C", the diaphragm 50 shown in FIGS. 13 and 14 is called "diaphragm 50D", and the diaphragm 50 shown in FIGS. 15 and 16 is called "diaphragm 50E". Further, in the following description, the surface of each diaphragm 50 attached to the housing 2 of the acoustic damper 1 will be referred to as "lower surface 55", and the surface opposite to the lower surface 55 will be referred to as "upper surface 56". Each diaphragm 50 is mainly subjected to vibration, ie load, along the direction extending between the lower surface 55 and the upper surface 56 . Each diaphragm 50 has a lower surface 55 and an upper surface 56 extending in a direction orthogonal to the load acting direction. It should be noted that at least the lower surface 55 and the upper surface 56 may have a shape along the outer surface of the housing 2 .

FIG. 7 is a perspective view showing the diaphragm 50A, and FIG. 8 is a perspective view showing the internal structure of a part of the diaphragm 50A cut away. A diaphragm 50A shown in FIGS. 7 and 8 is a space-filling solid in which a plurality of cubes 51A are combined to form a cubic outer surface. As shown in FIG. 8, the diaphragm 50A has a cavity 52A inside each cube 51A. In other words, each cube 51A has partition walls 53A that separate the cavities 52A.

FIG. 9 is a perspective view showing the diaphragm 50B, and FIG. 10 is a perspective view showing the internal structure of a part of the diaphragm 50B cut away. Diaphragm 50B shown in FIGS. 9 and 10 is a space-filling three-dimensional structure in which a plurality of triangular prisms 51B are combined to form a hexagonal prism-shaped outer surface. As shown in FIG. 9, the diaphragm 50B has a cavity 52B inside each triangular prism 51B. In other words, each triangular prism 51B has a partition wall 53B that partitions the cavity 52B.

FIG. 11 is a perspective view showing the diaphragm 50C, and FIG. 12 is a perspective view showing the internal structure of a part of the diaphragm 50C cut away. A diaphragm 50C shown in FIGS. 11 and 12 is a space-filling solid formed by combining a plurality of hexagonal prisms 51C. As shown in FIG. 12, the diaphragm 50C has a cavity 52C inside each hexagonal column 51C. In other words, each hexagonal column 51C has a partition wall 53C that partitions the cavity 52C.

FIG. 13 is a perspective view showing the diaphragm 50D, and FIG. 14 is a perspective view showing the internal structure of a part of the diaphragm 50D cut away. A diaphragm 50D shown in FIGS. 13 and 14 is a space-filling solid formed by combining a plurality of rhombic dodecahedrons 51D. As shown in FIG. 14, the diaphragm 50D has a cavity 52D inside each rhombic dodecahedron 51D. In other words, each rhombic dodecahedron 51D has a partition wall 53D that partitions a cavity 52D.

FIG. 15 is a perspective view showing the diaphragm 50E, and FIG. 16 is a perspective view showing the internal structure of a part of the diaphragm 50E cut away. A diaphragm 50E shown in FIGS. 15 and 16 is a space-filling solid formed by combining a plurality of truncated octahedrons 51E. As shown in FIG. 16, the diaphragm 50E has a cavity 52E inside each truncated octahedron 51E. In other words, each truncated octahedron 51E has partition walls 53E that separate cavities 52E.

As shown in FIGS. 7 to 16, each diaphragm 50 (50A, 50B, 50C, 50D, 50E) is a space-filling three-dimensional body having a cavity inside, thereby reducing the spring constant of each diaphragm 50. be able to. As shown in FIG. 6, it can be seen that the spring constants of diaphragm 50D combining rhombic dodecahedrons 51D and diaphragm 50E combining truncated octahedrons 51E are particularly small. Therefore, a structure in which each side extending between the upper surface 56 and the lower surface 55 extends obliquely with respect to the direction in which the load acts on each diaphragm 50 can obtain a smaller spring constant. Can be deformed under load.

As described above, the acoustic damper 1 according to the embodiment includes a housing 2 (acoustic damper main body) fixed to a vibration source and forming a passage 3 for taking in air vibrations generated by the vibration source, and a predetermined spring constant. and a diaphragm 50 attached to the outer surface of the housing 2 .

With this configuration, by attaching the diaphragm 50 having a predetermined spring constant to the outer surface of the housing 2 , the vibration of the housing 2 can be absorbed by the diaphragm 50 and the acoustic boundary condition of the acoustic damper 1 can be changed. As a result, the eigenvalue of the resonance frequency of the acoustic damper 1 can be changed and the sound pressure level can be reduced, so that the size of the acoustic damper 1 aiming at damping vibrations at the same resonance frequency can be achieved. Therefore, according to the embodiment, the vibration of the vibration source can be favorably damped by the acoustic damper 1 having a simpler configuration and a smaller size.

Further, the predetermined spring constant of diaphragm 50 is 10 N/mm or more and 100 N/mm or less.

This configuration allows the diaphragm 50 to deform under the action of a relatively small load. In other words, the diaphragm 50 can be deformed to absorb minute vibrations.

Also, the diaphragm 50 is a space-filling solid having a plurality of cavities inside.

With this configuration, diaphragm 50 having a predetermined spring constant can be easily obtained.

FIG. 17 is an explanatory diagram showing a first modification of the diaphragm of the first embodiment. FIG. 17 shows a modification of the diaphragm 50A as a space-filling three-dimensional body combining a plurality of cubes 51A shown in FIGS. That is, the vibration plate 50F shown in FIG. 17 is a space-filling three-dimensional structure obtained by combining a plurality of cubes 51F, and each cube 51F is provided with a cavity 52F. In other words, each cube 51F has partition walls 53F that separate the cavities 52F. The diaphragm 50F is provided with slits 54F between the partition walls 53F of the cubes 51F, as shown. That is, adjacent partition walls 53F of each cube 51F are separated from each other.

FIG. 18 is an explanatory diagram showing pressure strain characteristics of the diaphragm of the first modified example. A solid line in the figure indicates the pressure strain characteristic of the diaphragm 50A shown in FIGS. 7 and 8, and a broken line in the figure indicates the pressure strain characteristic of the diaphragm 50F. As shown, diaphragm 50F has a smaller spring constant than diaphragm 50A. That is, the diaphragm 50F is easily deformed with a smaller load than the diaphragm 50A by providing a slit between the partition walls 53F and separating them from each other. Therefore, by providing slits between the partition walls 53F that separate the plurality of cavities 52F, the spring constant of the diaphragm 50F can be made smaller, and the diaphragm 50F can be easily deformed in response to minute vibrations. In FIG. 17, the diaphragm 50 as a space-filling three-dimensional body in which the cubes 51A are combined is taken as an example, but in any diaphragm 50 shown in FIGS. may Also, the slits may be provided only between some of the partition walls.

FIG. 19 is an explanatory diagram showing a second modification of the diaphragm of the first embodiment. FIG. 19 shows a modification of the vibration plate 50A as a space-filling cube formed by combining a plurality of cubes 51A shown in FIGS. That is, the vibration plate 50G shown in FIG. 19 is a space-filling three-dimensional structure obtained by combining a plurality of cubes 51G, and a cavity (not shown) is provided inside each cube 51G. In other words, each cube 51G has partition walls 53G that partition the cavity. The diaphragm 50G is provided with slits 54G between partition walls 53G in the same manner as the diaphragm 50F. The diaphragm 50G has a shape in which the partition walls 53G of the cubes 51G are curved. That is, in the diaphragm 50A shown in FIGS. 7 and 8, the partition 53A of the cube 51A extends straight along the load acting direction (the direction extending between the lower surface 55 and the upper surface 56). The plate 50G extends while the partition wall 53G is curved along the load acting direction.

FIG. 20 is an explanatory diagram showing pressure strain characteristics of the diaphragm of the second modification. A solid line in the drawing indicates the pressure strain characteristic of the diaphragm 50A shown in FIGS. 7 and 8, and a broken line in the drawing indicates the pressure strain characteristic of the diaphragm 50G. Referring to FIGS. 18 and 20, it can be seen that diaphragm 50G has a smaller spring constant than diaphragms 50A and 50F. That is, the diaphragm 50G is easily deformed by a smaller load because the partition wall 53G extends while curving along the load acting direction. Therefore, by curving the partition wall 53F along the load acting direction, the spring constant of the diaphragm 50G can be made smaller, and the diaphragm 50G can be easily deformed in response to minute vibrations. In FIG. 19, the vibration plate 50 as a space-filling solid formed by combining the cubes 51A is taken as an example, but in any of the vibration plates 50 shown in FIGS. may Also, the partition may be curved only partially.

[Second embodiment]
Next, a diaphragm according to the second embodiment will be described with reference to FIGS. 21 to 24. FIG. 21 to 24 are explanatory diagrams showing specific examples of the diaphragm according to the second embodiment. 21 is referred to as "diaphragm 50H", the diaphragm 50 illustrated in FIG. 22 is referred to as "diaphragm 50I", the diaphragm 50 illustrated in FIG. 23 is referred to as "diaphragm 50J", The diaphragm 50 shown in FIG. 24 is called "diaphragm 50K". Also in the second embodiment, each diaphragm 50 mainly vibrates along the direction extending between the lower surface 55 and the upper surface 56, that is, the load is applied.

A diaphragm 50H shown in FIG. 21 is a truncated conical spring, that is, a disc spring. The diaphragm 50</b>H has a lower surface 55 at the opening on the large diameter side, and is fixed to the housing 2 at the lower surface 55 . However, the diaphragm 50</b>H may have a lower surface 55 fixed to the housing 2 at the opening on the smaller diameter side. A diaphragm 50I shown in FIG. 22 is obtained by combining two diaphragms 50H shown in FIG. 21 so as to face in opposite directions to each other. That is, the diaphragm 50I is formed by continuously stacking a plurality of diaphragms 50H. In the example shown in FIG. 22, the two diaphragms 50H are combined so as to contact each other at the small diameter side openings, but may be combined so as to contact each other at the large diameter side openings. . Further, the diaphragm 50I may be a combination of three or more diaphragms 50H.

A diaphragm 50J shown in FIG. 23 is a truncated quadrangular pyramid spring. Like the diaphragm 50H, the diaphragm 50J also has a lower surface 55 at the opening on the large diameter side, and is fixed to the housing 2 at the lower surface 55. As shown in FIG. However, the diaphragm 50</b>J may have a lower surface 55 fixed to the housing 2 at the opening on the smaller diameter side. A diaphragm 50K shown in FIG. 24 is obtained by combining two diaphragms 50J shown in FIG. 24 so as to face in opposite directions to each other. That is, the diaphragm 50K is formed by continuously stacking a plurality of diaphragms 50J. In the example shown in FIG. 24, the two diaphragms 50J are combined so as to contact each other at the openings on the smaller diameter side, but they may be combined so as to contact each other at the openings on the larger diameter side. . Also, the diaphragm 50K may be a combination of three or more diaphragms 50J.

By forming the diaphragm 50 into a truncated cone-shaped spring or a truncated quadrangular pyramid-shaped spring in this way, the spring constant of the diaphragm 50 can be easily adjusted, and the diaphragm 50 can be easily manufactured. can be configured. FIG. 25 is an explanatory diagram showing an example of analysis results of load-displacement characteristics of each diaphragm according to the second embodiment. The solid line in the figure indicates the load-displacement characteristics of the diaphragm 50H, the dashed line in the figure indicates the load-displacement characteristics of the diaphragm 50I, and the dashed-dotted line in the figure indicates the load-displacement characteristics of the diaphragm 50J. The two-dot chain line in the middle shows the load-displacement characteristics of the diaphragm 50K. As shown in the figure, it can be seen that the diaphragm 50I in which a plurality of frustum-shaped diaphragms 50H are combined can have a smaller spring constant than the single diaphragm 50H. Further, it can be seen that the diaphragm 50K obtained by combining a plurality of diaphragms 50J having a truncated pyramid shape can have a smaller spring constant than a single diaphragm 50J. Therefore, diaphragm 50I and diaphragm 50K can easily deform in response to minute vibrations.

In the first and second embodiments, the combustor 12 of the gas turbine 100 is used as a vibration source, and the acoustic damper 1 is attached to the outer surface of the transition piece 33 as a combustion tube. , may be attached to the outer surface of other vibration sources.

REFERENCE SIGNS LIST 1 acoustic damper 2 housing 3 passage 12 combustor 33 transition tube (combustion tube)
50, 50A, 50B, 50C, 50D, 50E, 50F, 50G, 50H, 50I, 50J, 50K Diaphragm 51A, 51F, 51G Cube 51B Triangular prism 51C Hexagonal prism 51D Rhombic dodecahedron 51E Truncated octahedron 52A, 52B, 52C, 52D, 52E, 52F Cavity 53A, 53B, 53C, 53D, 53E, 53F, 53G Partition wall 54F, 54G Slit 100 Gas turbine

Claims (7)

an acoustic damper body fixed to a vibration source and forming a passage for taking in air vibrations generated by the vibration source;
a diaphragm having a predetermined spring constant and attached to the outer surface of the acoustic damper body;
with
The diaphragm is a space-filling solid having a plurality of cavities inside,
The space-filling solid has slits between partition walls that separate the plurality of cavities,
An acoustic damper , wherein the partition wall of the space-filling solid is curved along the load acting direction . an acoustic damper body fixed to a vibration source and forming a passage for taking in air vibrations generated by the vibration source;
a diaphragm having a predetermined spring constant and attached to the outer surface of the acoustic damper body;
with
An acoustic damper, wherein the diaphragm is a truncated conical spring . an acoustic damper body fixed to a vibration source and forming a passage for taking in air vibrations generated by the vibration source;
a diaphragm having a predetermined spring constant and attached to the outer surface of the acoustic damper body;
with
The acoustic damper, wherein the diaphragm is a truncated quadrangular pyramid spring . 4. An acoustic damper according to claim 2 or 3 , wherein said diaphragm comprises a plurality of said springs arranged in a continuous stack. The acoustic damper according to any one of claims 1 to 4, wherein the predetermined spring constant of the diaphragm is 10 N/mm or more and 100 N/mm or less. Combustion characterized in that the acoustic damper according to any one of claims 1 to 5 is attached to the outer surface of the combustion cylinder, and air vibration of combustion gas flowing through the combustion cylinder is caused to flow into the acoustic damper. vessel. A gas turbine comprising the combustor according to claim 6 .

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