Damper arrangement for reducing combustion-chamber pulsation

Abstract

The invention concerns a damper arrangement for reducing combustion-chamber pulsation arising inside a gas turbine, wherein the gas turbine includes at least one compressor, a primary combustor which is connected downstream to the compressor, and the hot gases of the primary combustor are admitted at least to an intermediate turbine or directly or indirectly to a secondary combustor. The hot gases of the secondary combustor are admitted to a further turbine or directly or indirectly to an energy recovery, wherein at least one combustor is arranged in a can-architecture. At least one combustor liner includes air passages, wherein at least one of the air passages is formed as a damper neck. The damper neck being actively connected to a damper volume, and the damper volume is part of a connecting duct extending between a compressor air plenum and the combustor.

Claims

1. A damper arrangement for a gas turbine, the gas turbine including a compressor, a primary combustor connected downstream to the compressor and including a combustion chamber, and configured so that hot gases of the primary combustor are admitted at least to an intermediate turbine or directly or indirectly to a secondary combustor, and hot gases of the secondary combustor are admitted to a further turbine or directly or indirectly to an energy recovery, the damper arrangement, comprising: at least one combustor liner including a plurality of air passages for injecting a fluid into hot combustion products in between the primary combustor and the secondary combustor, wherein at least one of the air passages of the plurality of air passages is formed as a first damper neck, the first damper neck being connected to a first damper volume, wherein the first damper volume is an annular single chambered connecting duct extending between a compressor air plenum and the primary combustor, the first damper neck and the first damper volume configured to reduce pulsations of the combustion chamber wherein a fuel injector extends through the annular single chambered connecting duct.

2. The damper arrangement as claimed in claim 1, wherein the primary and secondary combustor are arranged in a can-architecture.

3. The damper arrangement as claimed in claim 1, wherein the primary combustor is arranged in an annular-architecture.

4. The damper arrangement as claimed in claim 1, wherein the secondary combustor is arranged in an annular-architecture.

5. The damper arrangement as claimed in claim 1, wherein the primary and the secondary combustor are arranged in an annular-architecture.

6. A damper arrangement as claimed in claim 1, wherein the air passages possess a circular, oval, slotted, rectangular, triangular, or polygonal flow cross section.

7. A damper arrangement as claimed in claim 1, comprising a plurality of first damper necks, the first damper neck being included in the plurality of first damper necks, wherein the plurality of first damper necks are arranged in a circumferential or quasi-circumferential direction with respect to the at least one combustor liner.

8. A damper arrangement as claimed in claim 1, comprising a plurality of first damper necks, the first damper neck being included in the plurality of first damper necks, wherein the plurality of first damper necks are arranged in a plurality of rows in a mutually spaced manner on a surface of the at least one combustor liner.

9. A damper arrangement as claimed in claim 1, wherein the first damper volume is disposed in circumferential or quasi-circumferential direction with respect to the at least one combustor liner.

10. A damper arrangement as claimed in claim 1, wherein the first damper neck bridges radially or quasi-radially an interspace from an adjacent or outside damper volume to the at least one combustor liner or to the air passages.

11. A damper arrangement as claimed in claim 1, wherein the first damper neck is disposed flush with an exterior wall of the at least one combustor liner.

12. The damper arrangement as claimed in claim 1, wherein a part of the first damper neck is disposed in an interior of the combustion chamber of the primary combustor and possesses a straight or an angled orientation.

13. A damper arrangement as claimed in claim 1, wherein the primary and/or secondary combustor has at least one premix burner.

14. A damper arrangement as claimed in claim 1, wherein the first damper neck penetrates into the interior of the combustion chamber.

15. The damper arrangement as claimed in claim 1, comprising: a second damper volume arranged concentrically with the first damper volume; and at least one second damper neck connected to the second damper volume.

16. The damper arrangement as claimed in claim 1, wherein the first damper neck includes the following dimensions or relations: a length greater than or equal to 5 mm and a cross-sectional area greater than 5 mm.sup.2.

17. The damper arrangement as claimed in claim 1, wherein the plurality of air passages includes dilution air holes and a sum of fluid flows injected by the air passages is in a range of 5 to 50% of a mass flow rate of combustion products of the primary combustor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is shown schematically in FIGS. 1 to 5 based on exemplary embodiments.

(2) Schematically, in the drawings:

(3) FIG. 1a shows a generic gas turbine using sequential combustion in a can-architecture;

(4) FIG. 1 b shows a generic gas turbine using sequential combustion in an annular-architecture;

(5) FIG. 2a shows a simple damper arrangement in a can-architecture;

(6) FIG. 2b shows a simple damper arrangement in an annular-architecture

(7) FIG. 3a shows a further generic gas turbine using sequential combustion in a can-architecture;

(8) FIG. 3b shows a further generic gas turbine using sequential combustion in an annular-architecture;

(9) FIG. 4a shows a double damper arrangement in a can-architecture;

(10) FIG. 4b shows a double damper arrangement in an annular-architecture

(11) FIGS. 5a-5d show various damper elements.

DETAILED DESCRIPTION

(12) A generic sketch of such a gas turbine is shown for example in FIG. 1a. Therein a compressor is followed by a combustor section, which consists of a number of combustor cans. The can architecture comprises a plurality of combustor cans arranged in an annular array about the circumference of the turbine shaft. The single combustor can enables an individual combustion operation of each can, and which will be no harmful interactions among individual cans during the combustion process.

(13) FIG. 1a shows a gas turbine 100 comprising a number of combustor cans. The combustor-can comprises sequential combustion areas or combustors 101, 102, for implementing the method according to the invention. Furthermore, the gas turbine comprises fundamentally a compressor 103, at least one burner 104, and at least one turbine 105. It is possible to dispose along the combustor can an intermediate turbine (not shown) and, additionally, downstream of this turbine a second burner system (not shown).

(14) Typically, the gas turbine system includes a generator (not shown) which at the cold end of the gas turbine, that is to say at the compressor 103, is coupled to a shaft 106 of the gas turbine 100. The primary combustor 101 and the secondary combustor 102 run in a combustor can-architecture, while the mentioned intermediate turbine is optionally. Fuel is injected into the primary combustor 101 via the first fuel injection 123, and into the secondary combustor 102 via the second fuel injection 124.

(15) Within these combustor cans a primary combustor is followed by a secondary combustor. Between these two combustors dilution air might be injected in order to control the inlet temperature of the secondary combustor and therefore the self-ignition time of the fuel injected therein by the second fuel injection. Finally the hot combustion gases are fed directly into the turbine 105 or into the intermediate or first turbine.

(16) As soon as the secondary combustor 102 is in operation, additional fuel (not shown) is added to the hot gases of the primary combustor 101. The hot gases are expanded in the subsequent turbine 105, performing work. The exhaust gases 107 can be beneficially fed to a waste heat boiler of a combined cycle power plant or to another waste heat application.

(17) One or more of the combustor cans be constructed as annular combustors, for example, with a large number of individual burners 104. Each of these burners 104 is supplied with fuel via a fuel distribution system and a fuel feed.

(18) Based on these findings the concept can be expected to work for an engine, which runs under sequential combustion (with or without a high pressure turbine) in a can-architecture, but not only.

(19) Referring to a sequential combustion the combination of combustors can be disposed as follows:

(20) At least one combustor is configured as a can-architecture, with at least one operating turbine.

(21) Both, the primary and secondary combustors are configured as sequential can-can architecture, with at least one operating turbine.

(22) The primary combustor is configured as an annular combustion chamber and the secondary combustor is built-on as a can configuration, with at least one operating turbine.

(23) The primary combustor is configured as a can-architecture and the secondary combustor is configured as an annular combustion chamber, with at least one operating turbine.

(24) Both, the primary and secondary combustor are configured as annular combustion chambers, with at least one operating turbine.

(25) Both, the primary and secondary combustor are configured as annular combustion chambers, with an intermediate operating turbine.

(26) Accordingly, in terms of CO emissions for a can-architecture, the interaction between individual cans is minimal or inexistent. On top of this leakages at the split plane, which are known to affect CO for annular concepts, will not impact the CO for a can engine, since for this architecture split line leakages into the combustor exist only at the latest end of the transition piece. Therefore for a can variant the described concept will be even more effective than for annular engine architecture.

(27) A gas turbine according to above mentioned concepts for implementing the damper method is a subject of the invention.

(28) If premix burners for the combustion can or for an annular combustion chamber (see EP 0 620 362 A1) are provided, these should preferably be formed by the combustion process and objects according to the documents EP 0 321 809 A1 and/or EP 0 704 657 A1, wherein these documents forming integral parts of the present description. In particular, said premix burners can be operated with liquid and/or gaseous fuels of all kinds. Thus, it is readily possible to provide different fuels within the individual cans. This means also that a premix burner can also be operated simultaneously with different fuels.

(29) The second or subsequent combustor is preferably carried out by EP 0 620 362 A1 or DE 103 12 971 A1, wherein these documents forming integral parts of the present description.

(30) Additionally, the following mentioned documents forming also integral parts of the present description:

(31) EP 0 321 809 A and B relating to a burner consisting of hollow part-cone bodies making up a complete body, having tangential air inlet slots and feed channels for gaseous and liquid fuels, wherein in that the center axes of the hollow part-cone bodies have a cone angle increasing in the direction of flow and run in the longitudinal direction at a mutual offset. A fuel nozzle, which fuel injection is located in the middle of the connecting line of the mutually offset center axes of the part-cone bodies, is placed at the burner head in the conical interior formed by the part-cone bodies.

(32) EP 0 704 657 A and B, relating to a burner arrangement for a heat generator, substantially consisting of a swirl generator, substantially according to EP 0 321 809 A and B, for a combustion air flow and means for injection of fuel, as well of a mixing path provided downstream of said swirl generator, wherein said mixing path comprises transaction ducts extending within a first part of the path in the flow direction for transfer of a flow formed in said swirl generator into the cross-section of flow of said mixing path, that joins downstream of said transition ducts.

(33) Furthermore, a fuel injector for use within a gas turbine reheat combustor it is proposed, utilising auto-ignition of fuel, in order to improve the fuel air mixing for a given residence time. The second fuel injection shown can for example be a fuel lance. However, any type fuel injection known for secondary combustors such as a for example flutes, or streamlined bodies with vortex generators such as lobes can be used Additionally, the following specific embodiments of this injector with oscillating gaseous fuel injection are envisaged:

(34) The oscillating gaseous fuel is injected normal to the flow of oxidant in sense of a cross-flow configuration.

(35) The oscillating gaseous fuel is injected parallel to the flow of oxidant in sense of an in-line configuration.

(36) The oscillating gaseous fuel is injected at an oblique angle, between 0 and 90 to the flow of oxidant.

(37) EP 0 646 705 A1, relating to a method of establishing part load operation in a gas turbine group with a sequential combustion, EP 0 646 704 A1, relating to a method for controlling a gas turbine plant equipped with two combustor chambers, and

(38) EP 0 718 470 A1, relating to method of operating a gas turbine group equipped with two combustor chambers, when providing a partial-load operation also form integral parts of the present description.

(39) Some of the compressed air 108 is tapped off as high-pressure cooling air, feed as cooling air to the first and/or secondary combustor or re-cooled via a high-pressure cooling air cooler (not shown) and fed as cooling air to the first and/or secondary combustor and, if necessary, to the first and/or second turbine.

(40) The characteristic of the invention according to FIG. 2a consists of an injection of cold air 110 into the hot combustion products 109 of the primary combustor 101. The mixing quality with respect to this operation is crucial since the burner system of the secondary combustor 102 requires a uniform inlet flow.

(41) At least a part of this cold air is injected directly from the compressor outlet plenum or subsequently of an air cooler (not shown). For such an implementation there is a connecting duct 111 between the relatively huge compressor plenum and the primary and/or secondary combustor 101, 102. Depending on the volume of the compressor plenum the connecting duct 111 should be advantageously designed in such a way that the system acts as a first acoustic damper 112 with respect to its volume, whereas a part of the connecting duct 111 can take over as a part of or functions as the first damper volume 112.

(42) Depending on the large volume the resulting efficiency is high and low frequencies can be addressed. The acoustic energy impinging on the damper results in an oscillation of the flow inside the damper neck 113. This amplification of the jet discharged by the dilution air holes 114 enhances the mixing of hot and cold air.

(43) A plurality of air holes 114 can be provided in one or more circumferentially disposed damper neck sections 115 on the combustor liner, respectively inner liner 116. The air holes 114 can be in the form of apertures that extend through the thickness of the inner liner 116. The air holes 114 can have any suitable cross-sectional size or shape. For instance, the air holes can be circular, oval, slotted, rectangular, triangular, or polygonal.

(44) Each of the air holes 114 can have a substantially constant cross-sectional area along its circumferential section 115, or the cross-sectional area of at least one of the air holes can be varied at least for a portion of its circumferential section. The air holes 114 can have the same cross section as the damper necks 113, effectively having the same function. They can also have a different cross section in order to provide air jets with a penetration into the combustion products 109, which differ from the air jets provided by the damper necks 113, for better mixing of cold air 110 with the combustion products 109.

(45) The air holes can be substantially identical to each other, or at least one of the air holes in one or more respects, including in any of those described above.

(46) The above identified dependencies can be expressed mathematically with respect to the damper resonance frequency as follows:

(47) Formula relating to the first damper volume 112 (FIG. 2a, 2b):

(48) $f=\frac{c}{2.Math.}\sqrt{\frac{A}{\mathrm{VL}}}$
with the following designations:
c=Speed of Sound
A=Neck Area
L=Neck Length
V=Damper Volume

(49) Relating to FIG. 3a the same configuration is shown in FIG. 1a. To avoid unnecessary repetition, reference is made to FIG. 1a.

(50) FIG. 4a shows an extended version with respect to FIG. 2a. In addition to FIG. 2a, a first damper volume 112a, according to the first damper volume 112 of FIG. 2a, a second damper volume 117 is provided, which is externally applied in concentrically or quasi concentrically manner. Both damper volumes 112a, 117 are connected individually to various damper neck sections, namely the inner first damper volume 112a is connected in fluid communication to the first damper necks 118 of a first section 115a, and the outer second damper volume 117 is connected in fluid communication to second damper necks 119 of a second section 115b.

(51) Bridging the interspace from the outside second damper volume 117 to the air entering into the combustor chamber 101 resp. 102 (see FIG. 1a) can be taken over by damper necks, pipes or capillary tubes. The mentioned elements are disposed flush with the inner liner 116, or they can penetrate the inner liner with different depths. In the latter case, the destined air flows from the respective damper volume 112, 112a, 117 directly through the damper neck 118, 119 into the combustor chamber.

(52) In FIG. 1 b a configuration as in FIG. 1a is shown but for an annular-architecture. To avoid unnecessary repetition, reference is made to FIG. 1a where the corresponding elements are shown.

(53) FIG. 2b shows a simple damper arrangement corresponding to that of FIG. 2a adapted for an annular-architecture. Because FIG. 2b shows a cut through an annular combustor the damper necks 113 and dilution air holes 114 are arranged on the outer and inner liners.

(54) Relating to FIG. 3b the same configuration is shown in FIG. 1 b. To avoid unnecessary repetition, reference is made to FIG. 1 b.

(55) In FIG. 4b a configuration as in FIG. 4a is shown but for an annular-architecture. To avoid unnecessary repetition, reference is made to FIG. 4a where the corresponding elements are shown. Because FIG. 4b shows a cut through an annular combustor the first damper necks 118 and second damper necks 119 are arranged on the outer and inner liners.

(56) Of course, the working with a damper arrangement with several individual damper volumes is feasible.

(57) The above identified dependencies can be expressed mathematically with respect to the damper resonance frequency as follows:

(58) Formula relating to the first damper volume 112a (FIG. 4a, 4b)

(59) $f1=\frac{c}{2}\sqrt{\frac{A1}{V1L1}}$
and

(60) Formula relating to the second damper volume 117 (FIG. 4a, 4b)

(61) $f2=\frac{c}{2}\sqrt{\frac{A2}{V2L2}}$
with the following designations:
c=Speed of Sound
A.sub.1 A.sub.2=Neck Area
L.sub.1, L.sub.2=Neck Length
V.sub.1, V.sub.2=Damper Volume

(62) FIGS. 5a-5d show various arrangements of damper necks, as they have already been discussed above:

(63) In FIG. 5a, the first and second damper necks 118, 119 are assembled flush with the inner liner 116, wherein the damper necks are characterized by the following dimensions with respect to a gas turbine with an average power:

(64) D=Diameter

(65) A=Cross-sectional area=Trough flow

(66) L=Length

(67) and by the following relations:

(68) L>5 mm

(69) A>5 mm.sup.2 typically >50 mm.sup.2, preferably >100 mm.sup.2

(70) The sum of all cold air flows injected via the dilution air holes 114 and damper necks 113, 118, 119, 120, 121, 122 can be in the range of 5 to 50% of the mass flow rate of combustion products 109.

(71) FIGS. 5b and 5c show various arrangements, in which the damper necks 120 foraminate in vertically or quasi vertically direction the inner liner. In this case the cold air flows directly from the respective damper volume to the combustor chamber (FIG. 5b), and/or via at least one lateral opening 110a along the damper neck 121 to the combustor chamber (FIG. 5c).

(72) FIG. 5d shows a pipe according to a damper function. It can be disposed as an angled injector 122 which is arranged in order to introduce an air fluid into the combustor chamber and can be oriented in any suitable manner. In one embodiment, the injector can be oriented in the horizontal direction of the combustor chamber. In other embodiments, one or more of the injectors can be oriented in a different direction from one or more of the other injectors.

(73) The configurations with damper necks 120, 121 as shown in FIGS. 5b and 5c or angled injectors 122 as shown in FIG. 5d can be used as first and second damper necks 118, 119.

(74) The second fuel injection shown in the FIGS. 1 to 4 has the form of lance. However, any type fuel injection known for secondary combustors such as a for example flutes, lobes can be used.