JPS5956618A - Transition piece for gas turbine - Google Patents

Abstract

PURPOSE:To uniformly feed steam to the periphery of a combustor funnel, by a method wherein a transition piece, guiding high pressure combustion gas, generated by a combustor, to a turbine nozzle, is of a double tube structure, and scroll, in which steam is introduced, is connected to the one end thereof. CONSTITUTION:A combustor 1 for gas turbine is constituted such that a combustor funnel 5 is contained therein, a flow sleeve 6 is mounted around the combustor lapper, a compressed air A from a compressor flows as shown by an arrow mark, and flows in the combustor lapper 5 from a swirler 7. The compressed air flowing in the lapper 5 is mixed with the fuel from a fuel injection nozzle 8 for combustion, and high pressure combustion gas is injected through a transition piece 9 to a turbine nozzle 10. In which case, the transition piece 9 is of a double tube structure consisting of a cylindrical outer tube 11, communicated with a hollow scroll 14 situated at the one end thereof, and an inner tube 12, and steam through a steam feed pipe 13 is supplied to the hollow scroll 14.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a transition piece for a gas turbine;
In particular, the present invention relates to a transition piece having a structure capable of uniformly supplying steam around a combustor wrapper and cooling the transition piece during supply of steam.

[Technical background of the invention and its problems]

Generally, in gas turbines, steam is injected into the power fluid to increase the mass flow, thereby increasing the gas turbine output, and further reducing the amount of nitrogen oxides (NOx) generated during the combustion process. I'm pointing. In such steam injection, it is desirable that the steam be uniformly injected and distributed in the air used for combustion. Conventionally, however, steam is injected either by a steam injection nozzle located proximal to the fuel injection nozzle to inject the steam outside the combustor wrapper in the same direction as the fuel injection nozzle, or between the combustor wrapper and the combustor casing. θ placed on the side of the combustor wrapper so that the steam is injected almost perpendicularly to the combustor wrapper.
Because the steam is injected by the steam injection nozzle, it is difficult to distribute it evenly around the combustor wrapper.

By the way, an industrial gas turbine consists of a compressor, a combustor, and a turbine. Air compressed by the compressor is mixed with fuel in the combustor and combusted, and the combustion gas is guided to the turbine. In this process, combustion gases are guided from the combustor liner to the turbine nozzle via a transition piece.

At this time, the transition piece comes into contact with high-temperature combustion gas, but this high-temperature combustion gas may cause rapid oxidation and corrosion at high temperatures, or even increase the thermal gradient within the transition piece. can cause high thermal stress.

Therefore, in conventional gas turbines, the transition bead has been cooled using air from the compressor.

In some gas turbines, air discharged from a compressor is circulated around a transition piece on its way to a combustor to provide convective cooling of the transition piece. Although this method of cooling the transida υ John piece has some effect,
The life of a transition piece is generally shorter than that of a combustor liner that has sufficient film cooling.

In this connection, it is conceivable to cool the transition piece using steam instead of using compressor discharge air. It is easy to see that if the transition piece is cooled with steam, the convective cooling of the air can also remove more heat from the transition piece, reducing thermal stress and thus extending the life of the transition piece.

[Purpose of enlightenment]

In consideration of the above-mentioned points, the main object of the present invention is to provide a transition piece for a gas turbine, which is provided with a run-up section for injected steam in order to uniformly supply steam around the combustor.

Another object of the present invention is to provide a transition piece for a gas turbine, which includes a structure in which the transition piece is cooled by steam while the steam flows through the run-up section of the transition piece.

[Summary of the invention]

According to the present invention, in order to achieve the above-mentioned object, the transition piece has a double cylinder structure consisting of a cylindrical outer cylinder and an inner cylinder, and is equipped with a scroll of one color in the middle at one end, and the hollow scroll is The outer cylinder is connected to the steam supply pipe, and the inner cylinder is connected to the outer skin of the scroll so that the space between the outer cylinder and the inner cylinder communicates with the space between the outer skin and the inner skin of the scroll. The tubes are each integrally connected to the inner skin of the scroll and have a sufficient length in the shaft direction to form a run-up section from the scroll to the opposite end of the scroll.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the accompanying drawings.

A typical combustor used in a gas turbine is shown generally at 1 in FIG. As is well known, the combustor 1 is of the type in which compressed air from a compressor (not shown) is directed in counterflow. The combustor 1 has a casing 2, which is connected at one end to a turbine casing 3. An end cover 4 is hermetically attached to the end of the casing 2 opposite to the turbine casing 3, and blocks the air inside the casing 2 from fire.

A cylindrical combustor wrapper 5 is housed within the combustor 1 and extends generally in the axial direction. A flow sleeve 6 is provided around the combustor wrapper 5 to cover the periphery of the wrapper 5, and compressed air from the compressor flows through the cylindrical combustor wrapper 5 and the cylindrical flow sleeve 6 as shown by arrow A. It flows from the swirl 7 into the combustor wrapper 5 through the space between. The compressed air that has flowed into the combustor wrapper 5 is mixed with fuel supplied from the fuel injection nozzle 8 and combusted. The resulting combustion gases are guided through a transition piece 9 connected to the combustor wrapper 5 to a turbine nozzle 1.0 in the turbine casing 3.

FIG. 2 shows an enlarged view of the transition piece 9 according to the invention. The transition piece 9 has a generally cylindrical shape, but is provided with a hollow scroll 14 having a rectangular cross section at one end. The transition piece 9 has a double cylinder structure consisting of an outer cylinder 11 and an inner cylinder 12. The outer cylinder 11 is integrally connected to the outer skin of the scroll 14, and the inner cylinder I2 is integrally connected to the inner skin of the scroll 14. The space between the inner cylinder 12 and the space between the outer skin and the inner skin of the scroll 14 communicate with each other. A steam artificial part 14a is formed in the upper center of the scroll 14, and the inlet part 6 is connected to a vertically arranged steam supply pipe 13. The transition piece 9 has an axial length sufficient to form a run-up section 15 from the scroll 14 to the opposite end. The inner cylinder 12 is connected to the combustor wrapper 5, and the outer cylinder 11 extends to the vicinity of the flow sleeve 6 arranged around the combustor wrapper 5.

Steam is passed from the steam supply pipe 13 to the inlet J4 of the scroll 14.
The inside of the scroll I4 is supplied through the opening a.

The steam supplied into the scroll 14 passes through the run-up section 15 through the space between the outer cylinder 11 and the inner cylinder 12 of the transition piece 9, and is supplied onto the outer periphery of the combustor wrapper 5, where it passes through the run-up section 15. Mixed with compressed air from the compressor. Initially, the steam is dispersed around the inner cylinder 12 of the transition piece 9 in the scroll 14, and the steam is dispersed in the scroll 14 around the inner cylinder 12 of the transition piece 9.
While passing through the run-up section 15 up to the top of the lap, the inner cylinder 12
This causes the υ combustor wrapper 5 to be more evenly distributed around the
evenly distributed over the outer circumference. This uniformly distributed steam is guided along the outer cylinder 11 that extends to the vicinity of the flow sleeve 6, and is passed between the combustor wrapper 5 and the flow sleeve 6.
It is then mixed with compressed air introduced into the swirl 7.

〔Effect of the invention〕

1. -H theory: As explained above, in the transition bead according to the present invention, there is a considerable length of run-up section from when steam is supplied from the steam supply pipe to when it reaches the outer periphery of the combustor wrapper. +5 t, to :l+ must be added, so it is possible to uniformly disperse the steam, which can effectively reduce the indulgence of oxidized carbon dioxide produced by combustion overheating. .

In addition, the transition bead, which is exposed to high-temperature combustion residue, can be effectively cooled by the steam passing through the run-up section. It is possible to reduce the number of occurrences and further extend the life of the transition piece.

4. TL of the drawing? 1 is a schematic cross-sectional view of a combustor equipped with a transition piece according to the invention, and 21 41 is an enlarged perspective view of the transition piece according to the invention.

■... Combustion chamber, 2... Casing, 3... Turbine cage/da, 5... Combustor wrapper, 6... Flow sleeve, End... Fuel injection nozzle, 9... Transition piece , 11...Outer cylinder, 12...Inner cylinder, 13
...Steam supply pipe, 14...Scroll, 14a...
・Person ``], 15... Run-up section.

Applicant's agent Hisashi Hatano

Claims (1)

[Claims] 1. A 4T L double cylinder structure consisting of a cylindrical outer cylinder 11<1 and an inner cylinder, with a hollow scroll at one end, and the hollow scroll has an inlet to which a steam supply pipe is connected. The outer cylinder is integrally connected to the outer skin of the scroll, and the inner cylinder is integrally connected to the inner skin of the scroll so that the space between the outer cylinder and the inner cylinder communicates with the space between the outer skin and the inner skin of the scroll, lH! has a length in the axial direction sufficient to form a run-up section from the scroll to the end opposite to the scroll side. Transition piece for gas turbines with the following characteristics. 2. The transition bead according to claim 1, wherein the entry date is formed at the center of the scroll. 3. The scroll has a rectangular cross section. The transition piece according to claim 1 or 2. 4. The inner cylinder is connected to the combustor wrapper, and the outer cylinder extends to the vicinity of the flow sleeve arranged around the combustor wrapper. A transition piece according to claim 1, characterized in that it is elongated.