Patent Application
20180180288
The present disclosure relates to a combustor and a gas turbine.
A gas turbine is provided with a combustor and a turbine which utilizes combustion gas produced through combustion of fuel by the combustor to generate a rotational force. The combustor includes an acoustic device called an acoustic liner (combustion oscillation reduction device) mounted thereto. An acoustic liner is capable of damping combustion oscillation of a predetermined frequency generated by combination of an acoustic mode and a combustion system.
For instance, Patent Document 1 discloses an acoustic liner which defines a gas space in communication with the inside of the transition piece of the combustor via a vent hole and which is capable of damping combustion oscillation of a predetermined frequency.
CITATION LIST
Patent Document 1: JP2009-97841A
Typically, an acoustic liner is designed to have a single tuning frequency, and is capable of damping combustion oscillation of the tuning frequency or a frequency around the tuning frequency.
However, in the combustion oscillation, a plurality of modes (combustion modes) with considerably different frequencies may occur due to various causes such as the combustion state. While it is desirable to be able to damp a greater number of combustion oscillation modes during operation of a gas turbine, combustion oscillation modes having a frequency considerably different from the tuning frequency cannot be damped with a single acoustic liner.
Thus, to damp a plurality of combustion oscillation modes having considerably different frequencies, it is necessary to provide a plurality of acoustic liners. However, the number of installable acoustic liners is limited due to the installation space and costs. That is, while it is desirable to damp a greater number of combustion oscillation modes, in reality, the number of combustion oscillation modes that can be damped is limited depending on the number of acoustic liners that can be provided.
In view of the above, an object of at least one embodiment of the present invention is to provide a combustor and a gas turbine provided with an acoustic device capable of damping a plurality of combustion oscillation modes.
(1) A combustor according to at least one embodiment of the present invention comprises: a combustion liner having a first region in which at least one first opening is formed; a nozzle configured to inject a fuel into the combustion liner; and a first acoustic device mounted to the combustion liner. The first acoustic device includes: a first casing portion having at least one first wall which is disposed facing the first region on an outer side of the combustion liner and which has at least one second opening formed thereon, the first casing portion defining, between the first region and the at least one first wall, at least one first space being in communication with an inside of the combustion liner through the at least one first opening; and a second casing portion having at least one second wall which is disposed facing the at least one first wall on an outer side of the first casing portion, the second casing portion defining, between the at least one first wall and the at least one second wall, at least one second space being in communication with the at least one first space through the at least one second opening.
In the combustor having the above configuration (1), the second space exists outside the first space and is in communication with the first space through the first opening, and thereby the first acoustic device has a plurality of tuning frequencies. Thus, it is possible to damp a plurality of combustion oscillation modes having different frequencies with the first acoustic device.
(2) In some embodiments, in the above configuration (1), the at least one first opening and the at least one second opening are disposed on the same position or on different positions in an axial direction of the combustion liner.
(3) In some embodiments, in the above configuration (1) or (2), the at least one second space includes a plurality of second spaces separated from one another by a partition wall and having different heights in a radial direction of the combustion liner.
In the combustor having the above configuration (3), the plurality of second spaces separated by the partition wall have different heights, and thereby the first acoustic device can have more tuning frequencies. Thus, it is possible to damp more combustion oscillation modes with the first acoustic device.
(4) In some embodiments, in the above configuration (3), the plurality of second spaces are arranged along a circumferential direction of the combustion liner.
In the combustor having the above configuration (4), the plurality of second spaces are arranged along the circumferential direction of the combustion liner, and thus it is possible to provide the plurality of second spaces having different heights with a simple configuration.
(5) In some embodiments, in the above configuration (3) or (4), the plurality of second spaces are arranged along an axial direction of the combustion liner.
In the combustor having the above configuration (5), the plurality of second spaces are arranged along the axial direction of the combustion liner, and thus it is possible to provide the plurality of second spaces having different heights with a simple configuration.
(6) In some embodiments, in the above configuration (5), the heights of the plurality of second spaces decrease in stages toward the nozzle in the axial direction of the combustion liner.
In the vicinity of flame, that is, in the vicinity of the nozzle, a combustion oscillation mode with a higher frequency tends to occur, compared to in a region farther from the flame. Corresponding to this tendency, in the combustor having the above configuration (6), the heights of the second spaces decrease in stages toward the nozzle in the axial direction of the combustion liner, and thereby it is possible to damp the combustion oscillation mode of a high frequency in the vicinity of the flame.
(7) In some embodiments, in any one of the above configurations (1) to (6), the first acoustic device is disposed within a range corresponding to an inner diameter of the combustion liner from a tip of the nozzle, in an axial direction of the combustion liner. Within the range corresponding to the inner diameter of the combustion liner from the tip of the nozzle, a larger number of combustion oscillation modes tends to occur than outside the range. Corresponding to this tendency, with the combustor having the above configuration (7), the first acoustic device is disposed within the range corresponding to the inner diameter of the combustion liner in the axial direction of the combustion liner, and thereby it is possible to damp a large number of combustion oscillation modes effectively.
(8) In some embodiments, in any one of the above configurations (1) to (7), the combustor further comprises a second acoustic device mounted to the combustor. The combustion liner further includes a second region in which at least one third opening is formed. The second acoustic device includes a third wall disposed facing the second region on an outer side of the combustion liner, the second acoustic device defining, between the second region and the third wall, at least one third space being in communication with the inside of the combustion liner through the at least one third opening.
With the combustor having the above configuration (8), it is possible to damp even more combustion oscillation modes by providing the second acoustic device in addition to the first acoustic device.
(9) In some embodiments, in the above configuration (8), a sum of a height of the first space and a height of the second space in a radial direction of the combustion liner is greater than a height of the third space, and the height of the first space is smaller than the height of the third space.
In the combustor having the above configuration (9), the first acoustic device has a tuning frequency corresponding to the height of the first space, and a tuning frequency corresponding to the sum of the height of the first space and the height of the second space. The second acoustic device has a tuning frequency corresponding to the height of the third space, and the tuning frequency of the second acoustic device is in between the two frequencies of the first acoustic device. Thus, it is possible to damp combustion oscillation modes continuously over a wide frequency range.
(10) In some embodiments, in the above configuration (8) or (9), the first acoustic device is disposed closer to the nozzle than the second acoustic device in the axial direction of the combustion liner.
The closer to the nozzle, a larger number of combustion oscillation modes tends to occur. Corresponding to this tendency, in the combustor having the above configuration (10), the first acoustic device is disposed closer to the nozzle than the second acoustic device in the axial direction of the combustion liner, and thereby it is possible to damp a large number of combustion oscillation modes effectively.
(11) A gas turbine according to at least one embodiment of the present invention comprises: the combustor according to any one of the above (1) to (10); and a turbine configured to generate a rotational force from combustion gas produced through combustion of the fuel by the combustor.
In the gas turbine having the above configuration (11), the second space exists outside the first space and is in communication with the first space through the first opening, and thereby the first acoustic device has a plurality of tuning frequencies. Thus, it is possible to damp a plurality of combustion oscillation modes having different frequencies with the first acoustic device.
According to at least one embodiment of the present invention, it is possible to provide a combustor and a gas turbine provided with an acoustic device capable of damping a plurality of combustion oscillation modes.
Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It is intended, however, that unless particularly specified, dimensions, materials, shapes, relative positions and the like of components described in the embodiments shall be interpreted as illustrative only and not intended to limit the scope of the present invention.
For instance, an expression of relative or absolute arrangement such as “in a direction”, “along a direction”, “parallel”, “orthogonal”, “centered”, “concentric” and “coaxial” shall not be construed as indicating only the arrangement in a strict literal sense, but also includes a state where the arrangement is relatively displaced by a tolerance, or by an angle or a distance whereby it is possible to achieve the same function.
For instance, an expression of an equal state such as “same” “equal” and “uniform” shall not be construed as indicating only the state in which the feature is strictly equal, but also includes a state in which there is a tolerance or a difference that can still achieve the same function.
Further, for instance, an expression of a shape such as a rectangular shape or a cylindrical shape shall not be construed as only the geometrically strict shape, but also includes a shape with unevenness or chamfered corners within the range in which the same effect can be achieved.
On the other hand, an expression such as “comprise”, “include”, “have”, “contain” and “constitute” are not intended to be exclusive of other components.
The compressor 2 sucks in and compresses atmosphere, which is external air, and supplies the compressed air to at least one combustor 3.
The combustor 3 combusts fuel supplied from outside by using air compressed by the compressor 2, thereby producing high-temperature gas (combustion gas).
The turbine 4 generates a rotational driving force in response to supply of high-temperature gas produced by the combustor 3, and outputs the generated rotational driving force to the compressor 2 and an external device.
More specifically, the combustor 3 includes a nozzle portion 10, a combustion liner 12, and a transition piece 14. The nozzle portion 10 has at least one nozzle 16 which injects fuel supplied from outside into the combustion liner 12. For instance, the nozzle 16 includes one pilot nozzle 16a, and a plurality of main nozzles 16b disposed concentrically around the pilot nozzle 16a.
The combustion liner 12 has a tube shape, and has a cylindrical shape, for instance. The nozzle portion 10 is joined to one end side (upstream end side) of the combustion liner 12, and an interior space (combustion space) 18 is defined inside the combustion liner 12, where fuel injected from the nozzle 16 is combusted. The interior space 18 is supplied with compressed air via gaps between the nozzles 16, and thereby the fuel reacts with the compressed air to be combusted, thus generating combustion gas.
The transition piece 14 has a tube shape and is joined to the other end side (downstream end side) of the combustion liner 12. The cross-sectional shape of the transition piece 14 gradually changes in the axial direction of the combustor 3, that is, the flow direction of the combustion gas. The transition piece 14 connects the combustion liner 12 to the inlet of the turbine 4. For instance, each of the combustion liner 12 and the transition piece 14 is formed by a plate having a plurality of cooling flow passages formed therein.
The gas turbine 1 includes the first acoustic device (first acoustic liner) 20 mounted to the combustor 3.
As shown in
The first casing portion 22 has at least one first wall 30 disposed facing the first region 26, on the outer side of the combustion liner 12. At least one first space 32 is defined between the first region 26 and the first wall 30 facing each other at a distance in the radial direction in the combustion liner 12. The first space 32 is in communication with the interior space 18 through the first opening 28. The first wall 30 has at least one second opening 34 formed thereon. For instance, the first casing portion 22 has two first side walls 35 having a U-shape in a cross section orthogonal to the circumferential direction of the combustion liner 12, and connected to both sides of the first wall 30 in the axial direction of the combustion liner 12. The first casing portion 22 is fixed to the combustion liner 12 by welding, for instance.
The second casing portion 24 has at least one second wall 36 (36a, 36b, 36c) disposed facing the first wall 30, on the outer side of the first casing portion 22. At least one second space 38 (38a, 38b, 38c) is defined between the first wall 30 and the second wall 36 (36a, 36b, 36c) facing each other at a distance in the radial direction of the combustion liner 12. The second space 38 (38a, 38b, 38c) is in communication with the first space 32 through the second opening 34.
In the above gas turbine 1, at least one second space 38 (38a, 38b, 38c) exists on the outer side of the first space 32 and is in communication with the first space 32 through the first opening 28, and thereby the first acoustic device 20 (20a to 20f) has a plurality of tuning frequencies ν1, ν2 (ν2a, ν2b, ν2c), as shown in
In some embodiments, the acoustic device 20a, 20e, 20f further includes a single second space 38a, as shown in
The first acoustic device 20a has a sound absorption property as shown in
In the first acoustic device 20a, from among the two tuning frequencies ν1, ν2 in
In some embodiments, the height H1 of the first space 32 is equal to the height H2 of the second space 38 (H1=H2).
In some embodiments, the height H1 of the first space 32 is greater than the height H2 of the second space 38 (H1>H2).
In some embodiments, the height H1 of the first space 32 is smaller than the height H2 of the second space 38 (H1<H2).
In some embodiments, as shown in
In the above gas turbine 1, the plurality of second spaces 38 (38a, 38b, 38c) separated by the partition walls 42 have different heights H2a, H2b, H2c, and thereby the first acoustic device 20b, 20c, 20d can have more tuning frequencies ν1, ν2 (ν2a, ν2b, ν2c). Thus, it is possible to damp more combustion oscillation modes with the first acoustic device 20b, 20c, 20d.
In
Furthermore, the partition wall 42 may be formed integrally with the second wall 36 (36a, 36b, 36c), or may be joined to the second wall 36 (36a, 36b, 36c) by welding or the like.
In other words, the second casing portion 24 may be formed integrally, or may be formed of a plurality of members.
Furthermore, even in a case in which the second space 38 has a constant height H2 as shown in
In some embodiments, as shown in
In the above gas turbine 1, the plurality of second spaces 38 (38a, 38b, 38c) are arranged along the circumferential direction of the combustion liner 12, and thus it is possible to provide the plurality of second spaces 38 (38a, 38b, 38c) having different heights H2 (H2a, H2b, H2c) with a simple configuration.
In some embodiments, as shown in
In the above gas turbine 1, the plurality of second spaces 38 (38a, 38b, 38c) are arranged along the axial direction of the combustion liner 12, and thus it is possible to provide the plurality of second spaces 38 (38a, 38b, 38c) having different heights H2 (H2a, H2b, H2c) with a simple configuration.
In some embodiments, as shown in
In the vicinity of flame, that is, in the vicinity of the nozzle 16, a combustion oscillation mode with a higher frequency tends to occur, compared to in a region farther from the flame. Corresponding to this tendency, in the above gas turbine 1, the heights H2 (H2a, H2b, H2c) of the second spaces 38 decrease in stages toward the nozzle 16 in the axial direction of the combustion liner 12, and thereby it is possible to damp the combustion oscillation mode of a high frequency in the vicinity of the flame.
In some embodiments, as shown in
In some embodiments, as shown in
In this case, the combustion liner 12 further includes the second region 54 having at least one third opening 52 formed thereon. The second acoustic device 50 has the third wall 56 disposed facing the second region 54 on the outer side of the combustion liner 12, and defines, between the second region 54 and the third wall 56, at least one third space 58 that is in communication with the inside of the combustion liner 12 through the at least one third opening 52.
As shown in
In some embodiments, as shown in
In the gas turbine 1 of the above configuration, the tuning frequency ν3 of the second acoustic device 50 is positioned between the two frequencies ν1, ν2 of the first acoustic device 20a. Thus, it is possible to damp combustion oscillation modes continuously over a wide frequency range.
In some embodiments, the sum (H1+H2) of the height H1 of the first space 32 and the height H2 of the second space 38 of the first acoustic device 20 in the radial direction of the combustion liner 12 is equal to the height H3 of the third space 48 of the second acoustic device 50. In this configuration, the tuning frequencies ν2 and ν3 are equal, and thereby it is possible to improve the sound absorption coefficient in the vicinity of the tuning frequencies ν2, ν3.
In some embodiments, the sum (H1+H2) of the height H1 of the first space 32 and the height H2 of the second space 38 of the first acoustic device 20 in the radial direction of the combustion liner 12 is smaller than the height H3 of the third space 58 of the second acoustic device 50. In this configuration, the tuning frequency ν3 is lower than the tuning frequency ν2, and it is possible to suppress the combustion oscillation mode of a relatively high frequency with the first acoustic device 20 while suppressing the combustion oscillation mode of a relatively low frequency with the second acoustic device 50.
In some embodiments, as shown in
The closer to the nozzle 16, a larger number of combustion oscillation modes tends to occur. Corresponding to this tendency, with the above gas turbine 1, the first acoustic device 20 is disposed closer to the nozzle 16 than the second acoustic device 50 in the axial direction of the combustion liner 12, and thereby it is possible to damp a large number of combustion oscillation modes effectively.
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
In some embodiments, the second opening 34 formed on the first wall 30 has a circular shape as shown in
In some embodiments, the ratio (opening ratio) of the total area of the second openings 34 to the area of the first wall 30 is set to be not greater than 5%.
In some embodiments, the diameter or the width of the second opening 34 is set to be smaller than the height H2 of the second space 38.
In some embodiments, the second openings 34 are arranged in a staggered (zig-zag) pattern as shown in
In some embodiments, the second opening 34 extends in the circumferential direction of the combustion liner 12 as shown in
The layout of the second openings 34 formed on the first wall 30 is not limited to the examples shown in
In some embodiments, a purge hole having an opening on the outer surface of the first acoustic device 20 may be formed on the first casing portion 22 or the second casing portion 24, for cooling the first space 32 or the second space 38. In this case, the purge hole brings the first space 32 or the second space 38 and the outside of the first acoustic device 20 into communication, so that compressed air flowing around the first acoustic device 20 flows into the first space 32 or the second space 38 during operation of the gas turbine 1. During operation of the gas turbine 1, the pressure around the first acoustic device 20 is higher than the pressure inside the combustion liner 12, and thus combustion gas does not flow out from the interior space 18 through the first opening 28.
In some embodiments, the first wall 30 and the second wall 36 extend along the axial direction and the circumferential direction of the combustion liner 12 so that the height H1 of the first space 32 is constant in the axial direction and the circumferential direction of the combustion liner 12, and the height H2 (H2a, H2b, H2c) of each second space 38 is constant in the axial direction and the circumferential direction of the combustion liner 12.
In some embodiments, the second space 38 has a rectangular shape in a cross section orthogonal to the circumferential direction of the combustion liner 12, and an annular or sector shape in a cross section orthogonal to the axial direction of the combustion liner 12.
In some embodiments, the first openings 28 and the second openings 34 are in different or same positions in the axial direction of the combustion liner 12.
Embodiments of the present invention were described in detail above, but the present invention is not limited thereto, and various amendments and modifications may be implemented.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-137077 | Jul 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/070051 | 7/6/2016 | WO | 00 |
