JPH10153129A - Gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve total efficiency of a gas turbine and reduce generation of by-product of combustion such as NOx. SOLUTION: A sealing mechanism has a brush seal 22 mountable on a linkage member 5 or a burner inner cylinder 16. The brush seal 22 minimize air leakage flowed into the linkage member 5 based on the tendency of a flowing amount through a spring clip 20 arranged between the linkage member 5 and the burner inner cylinder 16. As a result, the air which may be leaked into the linkage member 5 otherwise is flowed into the burner to generate a lean air-fuel mixture iniside the burner. The gas turbine assembling this mechanism attains low amount of NOx to be discharged and improves total operation efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustor capable of burning fuel in compressed air for a power generator such as a gas turbine power generator. In particular, the present invention
The present invention relates to a self-contained brush seal at a boundary between a combustor and a communication area of a gas turbine. The combustor-to-communication zone seal greatly reduces the amount of air that would otherwise flow into the combustor to leak into the communication, thus reducing the amount of harmful NOx produced by combustion. Further, the efficiency of the turbine device is improved.

[0002]

BACKGROUND OF THE INVENTION In gas turbines, fuel is burned in compressed air produced by a compressor in one or more combustors. Generally, a combustion chamber is formed by an outer cylinder in a combustion section of a turbine, and a plurality of combustors are provided in the combustion chamber in a circumferential direction. In the combustor, a connecting portion (one for each combustor, sometimes referred to as a transition piece) for distributing the high-temperature combustion gas to the turbine for expansion is provided in an outer cylinder of each combustor, or It is mechanically connected to the liner.

[0003] Air from the compressor section is distributed into the combustion section chamber, so that the air is exposed to the outer surface and the connections of the combustor liner before it enters the combustor through the inlet. As is known, a sufficient supply of intake air to the combustor is especially necessary to reduce the emissions of environmentally harmful combustion processes, mainly NOx, to acceptable levels. The availability of more supply air to the combustor allows for combustion of the fuel at lean air-fuel ratios. However, in known turbine constructions, there is a significant amount of air leakage through the mechanical connection where the combustor borders the interconnect, which otherwise would flow across the outer surfaces of the combustor and interconnect. Would enter the combustor inlet.

[0004] Currently known spring clips are:
It functions to mechanically connect the rear end of the combustor to the front end of the connecting member, but it has a total air flow rate of about 2% from the compressor section.
３3% leak into the connection, allowing the combustor to be bypassed. Also, after a long run of about 1-2 years, these spring clips are known to bypass even more of the total air flow to the combustor. In known diffusion flame combustors, these leakage levels are acceptable. However, with the advent of lean premixed combustors operating at high light-off temperatures, the NOx emission levels remain below acceptable levels with the air flow losses permitted by the current spring clips at the combustor / communication interface. Can not be.

[0005] Sealing devices are known for minimizing leakage at the interface between the rear end of the connection and the first stage nozzle support element. Such a sealing mechanism is disclosed in U.S. Pat.
Nos. 5,412 and 5,400,586, both addressed to Bagepalli et al. However, these patents disclose a communication member and a first member to minimize the leakage of combustion products to the communication / nozzle interface.
A brush seal device for sealing a space between a step nozzle and a step nozzle is disclosed. Although these patents do not disclose means for sealing the interface between the combustor and the communication area to minimize the leakage of compressed air into the communication area, but here the air does not otherwise To produce combustion products.

It is therefore an object of the present invention to provide a combustion section of a gas turbine having a seal at the boundary between the rear end of the combustor and the front end of the communication section in order to reduce the formation of NOx and improve the overall efficiency of the turbine system. Is desired.

[0007]

Accordingly, a general object of the present invention is to reduce the leakage of compressed air otherwise utilized to supply the combustor and to produce a very lean mixture of fuel and air. It is to provide a gas turbine combustion section that has the attendant benefits of combustor operation using the same and improves turbine efficiency.

[0008]

SUMMARY OF THE INVENTION Briefly, this and other objects of the present invention are directed to a compressor for compressing air and producing a hot gas by burning fuel in the compressed air. A combustor disposed adjacent to the combustor and having a gap between the combustor and a brush provided in the gap to minimize the compressed air leaking through the gap. This is achieved in a gas turbine having a seal and a turbine for expanding the hot gas generated by the combustor.

According to one embodiment of the present invention, the brush seal is a directional compliant bristle anchoring bed clamped between an upstream retainer and a downstream retainer. The upstream and downstream retainers provide mechanical support for sealing pressure loads. A retaining ring, which provides support for the brush seal, is attached to either the connecting member or the combustor, so that the brush seal is attached to the connecting member with the bristles slightly warped by the combustor or the bristles contact the connecting member. Or attached to the combustor. Axial and radial displacements between the combustor and the communication member are absorbed by the bristles of the seal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIG.
2 shows a part of the gas turbine 1 near the combustion unit 6. In addition to the combustion section 6, the gas turbine 1 has a compressor section 2
And a turbine unit 3. The present invention provides a combustor 4 for the gas turbine 1, in particular, which operates efficiently and has very low levels of NOx (eg, the gas turbine is at base load ignition temperature for gaseous fuel and does not use water or steam injection). Combustors designed to generate about 9 ppmv or less when operated).

The combustion section 6 is formed by an outer cylinder 18 of the gas turbine 1, and has a chamber 7 in which a plurality of combustors 4 are provided in a circumferential direction. Each of the combustors 4 has a premixing zone 14 and a combustion zone 10 downstream of the premixing zone 14. The fuels 11 and 12 and the compressed air 8 from the compressor 2 are mixed in a premixing zone 14 and burned in a combustion zone 10. The casing 13 extends outward from the front surface of the outer cylinder 18 and surrounds a part of the premixing region 14 and the combustor fuel supply pipe. The connecting part (or connecting member) 5 has a duct mechanically connected to the inner cylinder 16, which inner cylinder 16 surrounds the combustion area 10 and generally forms the rear end of the combustor 4. . The communication unit 5 is the combustor 4
Hot gas 9 generated by the turbine 3 for expansion
Lead to.

The front end of the connection 5 can be mechanically connected to the rear end of the combustor barrel 16 using some known mechanical couplings known to those skilled in the art. One currently known mechanical coupling is a spring clip 20, as shown in FIG. The spring clip 20 is an annular flexible member having a plurality of pieces that are integrated at narrow intervals in the circumferential direction. The spring clip 20 is used for the combustor inner cylinder 1.
6, the connecting member 5 rests on the upper curved surface 21 of the spring clip 20. Due to the presence of the small gap (not shown) between each piece of the spring clip 20, the piece deforms radially under the influence of the connecting member 5, so that the connecting member 5 generally comes into contact with the spring clip 20. It remains. Thus, the spring clip 20 allows the combustor 4 to be concentric with the inlet of the connecting member 5, and the contact between the connecting member 5 and the upper curved surface 21 of the spring clip 20
Ensure that the amount of air that leaks over the upper side of the zero to the connection is minimized. However, it is known that due to the presence of a small gap between the pieces forming the spring clip 20, air flowing from the compressor section 2 to the combustor inlet leaks into the communication section 5 through the gap. Thus, and as described above, the spring clip 20
Takes into account that a significant amount of air leaking into the communication, which would otherwise be used to supply the combustor, results in reduced turbine efficiency and undesirable NOx emissions.

In order to reduce the amount of leakage through the mechanical interface between the combustor inner tube 16 and the connecting member 5, a sealing mechanism according to the present invention is shown in FIGS. The brush seal 22 has a densely planted bed of directionally compliant bristles 24 clamped by an upstream holding member 26 and a downstream holding member 28. Upstream holding member 26 and downstream holding member 2
8 provides mechanical support for the seal pressure load acting on the brush seal 22. The retaining ring 30 further provides mechanical support for the brush seal 22 to the inner surface of the connecting member 5. The means for mechanically attaching the brush seal within the combustor-communication member interface is not intended to be limited to the joints described herein, but any other suitable means for mechanically securing the brush seal in place. Will be known to traders.

Referring to FIG. 4, the ends of the bristles 24 of the brush seal 22 are formed on a circumferential surface 32 so that the bristles 24 fit snugly on the outer peripheral surface of the combustor inner tube 16. . The densely planted bed of bristles 24, which is directionally compliant, can be found in the Journal of Turbomachin
ary) Volume 118, published in 1996. E.
Chap (RE Chupp) and G.E. F. Although it can be optimally designed to minimize air leakage through the seal according to the instructions described in GF Holle, "Generalization of Circular Brush Seal Leakage Through Randomly Arranged Bristle Beds" That description is incorporated by reference in its entirety as part of the specification.

In the embodiment shown in FIG. 2, the brush seal 22 according to the present invention is attached to the connecting member 5 with bristles 24 slightly deformed by the combustor inner tube 16.
However, the brush seal 22 can also be attached to the combustor barrel 16 using the same type of retention mechanism described herein, such that the bristles 24 contact the communication member 5.

Referring again to FIG. 1, the operation of the combustor 4 is as follows. At start-up, the compressor 2 is turned up to the ignition speed, and when the compressor rotor is accelerated, compressed air 8 from the compressor 2 flows into the chamber 7 of the combustion section.
Part of the compressed air 8 crosses the outer surface of the combustor inner cylinder 16 and the communication member 5. Referring to FIG. 2, a part of the compressed air 8 has a tendency to flow through a spring clip 20 at the boundary between the combustor 4 and the connecting member 5. However, in accordance with the present invention, the brush seal 22 minimizes air leakage that tends to flow through the spring clip 20 and into the communication member 5, which air is
And produces a leaner mixture of air and fuel in the combustor 4. According to the present invention, leakage through known spring clips is reduced to less than one percent. The brush seal according to the present invention also absorbs thermal expansion and other axial and radial movement between the combustor and the communication member.

A sealing mechanism, such as a brush seal 22, according to the present invention is associated with any other known mechanical linkage, such as a stand-off pin, for mechanically securing the combustor to the communication member. Can be used to seal the interface between the combustor and the connecting member. The seal mechanism only needs to be located downstream of the combustor and the mechanical coupling of the communication member to minimize the amount of air leaking into the communication member through the coupling.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics of the invention and, therefore, is intended to show the scope of the invention rather than the appended specification Reference should be made to the claims.

[Brief description of the drawings]

FIG. 1 is a partial axial sectional view of a gas turbine in the vicinity of a combustor.

FIG. 2 is an enlarged view of a section AA of FIG. 1 showing a brush seal according to a preferred embodiment of the present invention.

FIG. 3 is an enlarged view of a BB section of FIG. 2;

FIG. 4 is an enlarged view of a cross section of the brush seal taken along line CC of FIG. 2;

[Explanation of symbols]

1 gas turbine, 2 compressor section, 3 turbine section, 4
Combustor, 5 communication members, 6 combustion section, 8 compressed air,
9 High-temperature gas, 10 combustion zone, 11, 12 fuel, 13
Casing, 14 premixing area, 16 inner cylinder, 18
Outer cylinder, 20 spring clips, 21 upper curved surface, 22
Brush seal, 24 bristles, 26, 28 holding member,
30 Retaining ring.

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Raymond e Chap Carnary Drive 3891, Oviedo, Florida, USA

Claims (1)

[Claims] A compressor that compresses air; a combustor that generates a high-temperature gas by burning fuel in the compressed air; a compressor that is disposed adjacent to the combustor and between the combustor. A communication member having a gap therein; a brush seal provided in the gap to seal the compressed air from leaking through the gap; and a turbine for expanding the hot gas generated by the combustor. gas turbine.