Gas turbine combustor

Abstract

A gas turbine combustor is provided with a combustor basket where combustion gas flows, the combustion gas being produced by combustion of fuel injected from a nozzle, and a first resonance device and a second resonance device mounted on an outer surface of the combustor basket. The second resonance device is disposed on a downstream side from the first resonance device in a flow of the combustion gas and damps combustion oscillation of a frequency higher than the first resonance device. The first and second resonance devices are acoustic liners each having a housing mounted to the outer surface of the combustor basket. A resonance space surrounded by the housing and the outer surface of the combustor basket communicates with an interior space of the combustor basket via a plurality of acoustic holes formed in the combustor basket.

Claims

1. A gas turbine combustor comprising: a combustor basket in which combustion gas flows, the combustion gas being produced by combustion of fuel injected from at least one nozzle; a first resonance device mounted on an outer surface of the combustor basket; and a second resonance device for damping combustion oscillation of a frequency higher than the first resonance device, the second resonance device being mounted on the outer surface of the combustor basket so as to be disposed on a downstream side from the first resonance device in a flow of the combustion gas, wherein the first resonance device is a first acoustic liner having a first housing mounted to the outer surface of the combustor basket, the first housing forming a first resonance space, wherein the second resonance device is a second acoustic liner having a second housing mounted to the outer surface of the combustor basket, the second housing forming a second resonance space, wherein the first resonance space and the second resonance space each communicate with an interior space of the combustor basket via a plurality of acoustic holes formed in the combustor basket, and wherein the second resonance device is housed in a first space surrounded by an outer surface of a downstream end of the combustor basket and an upstream end of a transition piece for introducing the combustion gas produced in the combustor basket to a turbine, the transition piece being arranged so that the upstream end of the transition piece overlaps an outer periphery of the downstream end of the combustor basket, wherein the second resonance space is directly communicated with the interior space of the combustor basket via the plurality of acoustic holes not through the first resonance space.

2. A gas turbine combustor, comprising: a combustor basket in which combustion gas flows, the combustion gas being produced by combustion of fuel injected from at least one nozzle; a first resonance device mounted on an outer surface of the combustor basket; and a second resonance device mounted on the outer surface of the combustor basket so as to be disposed on a downstream side from the first resonance device in a flow of the combustion gas, wherein the first resonance device and the second resonance device each have a respective resonance space, wherein each resonance space is surrounded by the outer surface of the combustor basket and a respective acoustic liner mounted to the outer surface of the combustor basket, wherein each resonance space communicates with an interior space of the combustor basket via a respective plurality of acoustic holes formed in the combustor basket, and wherein the second resonance device is housed in a first space surrounded by an outer surface of a downstream end of the combustor basket and an upstream end of a transition piece for introducing the combustion gas produced in the combustor basket to a turbine, the transition piece being arranged so that the upstream end of the transition piece overlaps an outer periphery of the downstream end of the combustor basket, wherein the gas turbine combustor further comprises a clip for connecting the upstream end of the transition piece to the downstream end of the combustor basket to each other, the clip being disposed in a space surrounded by the upstream end of the transition piece and the outer surface of the downstream end of the combustor basket, wherein the second resonance device is housed in a second space surrounded by the clip and the outer surface of the downstream end of the combustor basket.

3. The gas turbine combustor according to claim 1, further comprising a baggy clip for connecting the upstream end of the transition piece to the downstream end of the combustor basket to each other, the baggy clip being disposed in the first space, wherein the second resonance device is housed in a second space surrounded by the baggy clip and the outer surface of the downstream end of the combustor basket.

4. The gas turbine combustor according to claim 1, further comprising: a spring clip for connecting the upstream end of the transition piece to the downstream end of the combustor basket to each other, the spring clip being disposed in the first space; and a baggy clip for pressing the spring clip toward the upstream end of the transition piece, wherein the second resonance device is housed in a second space surrounded by the baggy clip and the outer surface of the downstream end of the combustor basket.

5. The gas turbine combustor according to claim 1, wherein the resonance space of the second resonance device has a first height smaller than a second height of the resonance space of the first resonance device.

6. The gas turbine combustor according to claim 1, wherein the nozzle includes a pilot nozzle arranged on a center axis of the combustor basket and a plurality of main nozzles arranged on an outer circumference of the pilot nozzle, and wherein a relationship of 0.8L2/D21.1 is established where D2 is a diameter of the combustor basket at a mounting position of the second resonance device and L2 is a distance between a downstream end of a main-nozzle external cylinder surrounding the main nozzle and the mounting position of the second resonance device.

7. The gas turbine combustor according to claim 1, wherein a relationship of 0.05W2/D20.3 is established where D2 is a diameter of the combustor basket at a mounting position of the second resonance device and W2 is a width of the resonance space of the second resonance device in a longitudinal direction of the combustor basket.

8. The gas turbine combustor according to claim 1, wherein a relationship of 0.005h2/D20.02 is established where D2 is a diameter of the combustor basket at a mounting position of the second resonance device and h2 is a height of the resonance space of the second resonance device.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a cross-sectional view of a gas turbine combustor in relation to an embodiment.

(2) FIG. 2 is a cross-sectional view of the gas turbine combustor near resonance devices in relation to an embodiment.

DETAILED DESCRIPTION

(3) 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 in these embodiments, dimensions, materials, shape, its relative positions and the like shall be interpreted as illustrative only and not limitative of the scope of the present invention.

(4) FIG. 1 is a cross-sectional view of the gas turbine combustor in relation to an embodiment. FIG. 2 is a cross-sectional view of the gas turbine combustor near resonance devices in relation to an embodiment.

(5) As shown in FIG. 1, a gas turbine combustor (hereinafter, simply described as a combustor) 1 is provided with nozzles 2, 3 for injecting fuel, a combustor basket (a combustor liner) 4 in which the combustion gas produced by combustion of the fuel flows, and a transition piece 6 connected to the combustor basket 4.

(6) The combustor 1 forms a gas turbine, with a compressor and a turbine. In the gas turbine, compressed air produced in the compressor is supplied to the combustor 1 as combustion air and combustion gas produced in the combustor 1 is supplied from the combustor basket 4 to the turbine via the transition piece 6. In this manner, the turbine is driven by the combustion gas.

(7) The combustor 1 is a premix combustor of a multi-nozzle type with a combination of a pilot nozzle 2 and a main nozzle 3. The pilot nozzle 2 is arranged on a center axis of the combustor basket 4. On an outer circumference of the pilot nozzle 2, a plurality of main nozzles 3 is arranged to surround the pilot nozzle 2. Tips of the main nozzles 3 are covered by a main-nozzle external cylinder 5.

(8) The fuel injected from the pilot nozzle 2 is ignited when mixed with the compressed air, thereby forming a flame downstream from the pilot nozzle 2. The fuel injected from the main nozzle 3 is ignited by the flame formed downstream from the pilot nozzle 2, thereby forming a flame downstream from each of the main nozzles 3. As a result, a flow of the combustion gas having a high temperature and flowing toward the transition piece 6 is formed in an interior space of the combustor basket 4.

(9) The transition piece 6 is connected to the combustor basket 4 by means of a spring clip 8. The transition piece 6 is arranged on an outer circumferential side of the combustor basket 4 and an upstream end of the transition piece 6 overlaps a downstream end of the combustor basket 4. The spring clip 8 has one end fixed to the outer periphery of the downstream end of the combustor basket 4 and the other end being a free end. Thus, the combustor basket 4 and the transition piece 6 are connected to each other by an elastic force of the spring clip 8. Further, a baggy clip 9 is provided between the spring clip 8 and the combustor basket 4. The baggy clip 9 presses the spring clip 8 against the inner periphery of the transition piece 6. In this manner, the combustor basket 4 and the transition piece 6 are firmly connected to each other.

(10) On the outer surface of the combustor basket 4, a first resonance device 10 and a second resonance device 20 are provided to reduce combustion oscillation. The first resonance device 10 and the second resonance device 20 may be arranged over the entire circumference of the combustor basket 4, or partially arranged in the circumferential direction of the combustor basket 4.

(11) As shown in FIG. 2, the first resonance device 10 is an acoustic liner with a first housing 12 attached to the outer surface of the combustor basket 4 by welding. A first resonance space 14 is surrounded by the first housing 12 and the outer surface of the combustor basket 4. The first resonance space 14 communicates with the interior space of the combustor basket 4 via a plurality of acoustic holes 16 formed in the combustor basket 4. Thus, air oscillation (a pressure wave) caused by the combustion oscillation generated in the combustor basket 4 is caught in the acoustic holes 16 so as to resonate. More specifically, the air in the first resonance space 14 and the air in the acoustic holes 16 together form a resonant system as the air in the first resonance space 14 functions as a spring. With respect to oscillation of a resonant frequency of this resonant system, the air in the acoustic hole 16 resonates intensely. The friction generated in the process decreases amplitude of the combustion oscillation.

(12) Further, a frequency band of the combustion oscillation that can be damped by the first resonance device 10 is arbitrarily settable by adjusting the diameter of the acoustic hole 16 (the sectional area), the size of the first resonance space 14 (a height h.sub.1 and a width W.sub.1 of the first resonance space 14), and the like.

(13) Further, in the first housing 12, a purging hole 18 is formed so that a part of the compressed air (the combustion air) flowing outside the combustor basket 4 enters the first resonance space 14. This prevents damages of the first housing 12 caused by contacting the high temperature combustion gas. The compressed air flows in a direction opposite to the combustion gas flowing in the interior space of the combustor basket 4, as shown in FIG. 2.

(14) In some embodiments, a mounting position of the first resonance device 10 is determined so that a relationship of 0.4L.sub.1/D.sub.10.7 is established where D.sub.1 is a diameter (an inner diameter) of the combustor basket 4 at the mounting position of the first resonance device 10 (see FIG. 1) and L.sub.1 is a distance between a downstream end of the main-nozzle external cylinder 5 and the mounting position of the first resonance device 10 (see FIG. 2). The mounting position of the first resonance device 10, herein, is a center position of a width of the first resonance device 10 in a longitudinal direction of the combustor basket 4.

(15) Further, in some embodiments, a width W.sub.1 of the first resonance space 14 in the longitudinal direction of the combustor basket 4 (see FIG. 2) is determined so that a relationship of 0.3W.sub.1/D.sub.10.6 is established where D.sub.1 is the diameter of the combustor basket 4 at the mounting position of the first resonance device 10.

(16) Furthermore, in some embodiments, a height h.sub.1 of the first resonance space 14 (see FIG. 2) is determined so that a relationship of 0.03h.sub.1/D.sub.10.1 is established where D.sub.1 is the diameter of the combustor basket 4 at the mounting position of the first resonance device 10.

(17) In contrast, the second resonance device 20 is arranged on a downstream side from the first resonance device 10 in a flow of the combustion gas. For instance, the second resonance device 20 may be arranged in the area where the transition piece 6 overlaps the combustor basket 4.

(18) In at least one embodiment, a mounting position of the second resonance device 20 is determined so that a relationship of 0.8L.sub.2/D.sub.21.1 is established where D.sub.2 is a diameter (an inner diameter) of the combustor basket 4 at the mounting position of the second resonance device 20 (see FIG. 1) and L.sub.2 is a distance between the downstream end of the main-nozzle external cylinder 5 and the mounting position of the second resonance device 20 (see FIG. 2). As a result, the second resonance device 20 is arranged closer to the flame position when the combustion oscillation of high frequency occurs and thus, the combustion oscillation of high frequency can be effectively suppressed by the second resonance device 20.

(19) The mounting position of the second resonance device 20, herein, is a center position of a width of the second resonance device 20 in a longitudinal direction of the combustor basket 4.

(20) Just like the first resonance device 10, the second resonance device 20 is also an acoustic liner having a second housing 22 attached to the outer surface of the combustor basket 4. A second resonance space 24 is surrounded by the second housing 22 and the outer surface of the combustor basket 4. The second resonance space 24 communicates with the interior space of the combustor basket 4 via a plurality of acoustic holes 26 formed in the combustor basket 4. Thus, with a mechanism similar to the case of the first resonance device 10, the resonance device 20 is capable of damping the combustion oscillation of a prescribed frequency. In the second housing 22, a purging hole 28 is formed so that a part of the compressed air flowing outside the combustor basket 4 enters the second resonance space 24.

(21) A frequency band of the combustion oscillation that can be damped by the second resonance device 20 is arbitrarily settable by adjusting the diameter (the sectional area) of the acoustic hole 26, the size of the second resonance space 24 (a height h.sub.2 and a width W.sub.2 of the second resonance space 24), and the like. Further, the frequency band of the combustion oscillation that can be damped by the second resonance device 20 is set higher than the frequency band of the combustion oscillation that can be damped by the first resonance device 10.

(22) In at least one embodiment, a width W.sub.2 of the second resonance space 24 in the longitudinal direction of the combustor basket 4 (see FIG. 2) is determined so that a relationship of 0.05W.sub.2/D.sub.20.3 is established where D.sub.2 is a diameter of the combustor basket 4 at the mounting position of the second resonance device 20.

(23) As a result, while downsizing the second resonance device 20, the second resonance device 20 is capable of effectively suppressing the combustion oscillation of a particular high-frequency wave outside the frequency band of the first resonance device 10.

(24) Further, in at least one embodiment, a height h.sub.2 of the second resonance space 24 (see FIG. 2) is determined so that a relationship of 0.005h.sub.2/D.sub.20.02 is established where D.sub.2 is the diameter of the combustor basket 4 at the mounting position of the second resonance device 20.

(25) As a result, while downsizing the second resonance device 20, it is possible to achieve a significant damping effect on the combustion oscillation of the high-frequency wave by the second resonance device 20.

(26) Further, in at least one embodiment, the height h.sub.2 of the second resonance space 24 is smaller than the height h.sub.1 of the first resonance space 14.

(27) By setting the height h.sub.2 of the second resonance space 24 of the second resonance device 20 relatively small in this manner, the combustion oscillation of the high-frequency wave can be damped effectively in the second resonance device 20. Further, by downsizing the second resonance device 20, layout of the second resonance device 20 is made easier. For instance, it becomes possible to house the second resonance device 20 in a space surrounded by the baggy clip 9 and the outer surface of the combustor basket 4, thereby utilizing the space under the baggy clip 9.

(28) As described above, in the above embodiments, in addition to the first resonance device 10, the second resonance device 20 is provided to damp the combustion oscillation of the frequency wave higher than the first resonance device 10. Thus, the combustion oscillation of the particular high-frequency wave below or above the frequency band of the first resonance device 10 can be damped by the second resonance device 20. Moreover, by arranging the second resonance device 20 downstream from the first resonance device 10 in the flow of the combustion gas, the second resonance device 20 is arranged nearer to the flame position of the case when the combustion oscillation of the particular high-frequency wave occurs below or above the frequency band of the first resonance device 10, thereby improving the damping effect on the combustion oscillation of the high-frequency wave by the second resonance device 20. Further, by arranging the first and second resonance devices 10, 20, instead of one wide resonance device, it is possible to suppress the increase of the mounting area of the resonance devices 10, 20, and also to avoid the decline in the supply amount of the compressed air for combustion by minimizing the number of the purging holes 18, 28 which the resonance device normally has.

(29) While the embodiments of the present invention have been described, it is obvious to those skilled in the art that various changes may be made without departing from the scope of the invention.

REFERENCE SIGNS LIST

(30) 1 Gas turbine combustor (Combustor) 2 Pilot nozzle 3 Main nozzle 4 Combustor basket 5 Main-nozzle external cylinder 6 Transition piece 8 Spring clip 9 Baggy clip 10 First resonance device 12 First housing 14 First resonance space 16 Acoustic hole 18 Purging hole 20 Second resonance device 22 Second housing 24 Second resonance space 26 Acoustic hole 28 Purging hole