JP3054420B2 - Gas turbine combustor - Google Patents

Description

The present invention relates to a gas turbine combustor, and more particularly to a gas turbine combustor that cools a combustor transition piece using air.

(Prior Art) Conventionally, a transition piece cooling structure of a gas turbine combustor has a flow sleeve provided on a combustor transition piece as disclosed in Japanese Patent Application Laid-Open No. 62-218732. By drilling a hole in and blowing out cooling air toward the transition piece,
This is a method for cooling the transition piece.

The conventional combustor transition piece is configured as shown in FIG. 11, and a part of the compressed air compressed by the compressor a is blown out from a cooling hole c formed in the flow sleeve b to make the transition piece d. To cool. The hole formed in the flow sleeve b has a large-diameter air hole e for air intake, in addition to the small-diameter cooling hole c. After cooling the transition piece d and the liner g while passing through f, it was guided to the head of the gas turbine combustor as combustion air.

(Problems to be Solved by the Invention) However, the transition piece d of the gas turbine combustor has a circular cross section at the connection with the liner g, but the connection with the turbine h as shown in FIG. It is almost fan-shaped. For this reason, the air passage i also has a substantially fan shape, and the air flowing between the flow sleeve b and the transition piece d has a different flow resistance due to the difference in the shape, and the flow is biased toward the axis of the gas turbine and the gas flows. It was flowing into the head of the turbine combustor.

That is, the circumferential distribution flowing between the combustor flow sleeve f and the liner g shown in FIG. 11 is shown by a broken line in FIG. In this conventional example, the amount of inflowing air is large toward the rotation axis of the gas turbine, and the outside decreases in the opposite direction. When examining the combustion state when such an air flow distribution is made, as shown in FIG. 10, the mixture ratio of fuel and air (fuel-air ratio) is uneven between the shaft side of the gas turbine and the outside thereof. Yes, it will not be even. And the mixture ratio of fuel and air is an important factor of combustion, and if this value is large, it will burn stably,
If it becomes smaller, the flame disappears and it becomes impossible to sustain combustion.

However, in the conventional gas turbine combustor, the fuel-air ratio was set to a value higher than the flammability limit so as to stably burn, but now the nitrogen oxide (NOx) contained in the exhaust gas is reduced. Therefore, lean combustion (low temperature combustion) having a small fuel-air ratio is required. Since the fuel-air ratio is set near the flammability limit to perform such lean combustion, if there is a bias in the air flow rate in the circumferential direction of the combustor as described above,
Some areas are below the flammable limit. As a result, unburned components such as carbon monoxide (CO) and hydrocarbons (UH
C) will be released in large quantities.

In such a case, combustion becomes extremely unstable, and large pressure fluctuations occur inside the liner of the combustor, causing cracks in the liner, which is a combustor part, cracks in the flow sleeve weld, and wear of the connection. This causes a problem that parts need to be repaired or replaced, and that the entire gas turbine is excited, and the gas turbine is stopped due to excessive vibration.

Also, the transition piece d of the gas turbine combustor
Demands a cooling air source from the compressor a, but if the cooling air is distributed to the transition piece d as a large amount of cooling air, the amount of combustion gas to be supplied to the turbine h is reduced. And the output of the gas turbine cannot be increased.

The present invention has been made in view of the above circumstances, and provides a gas turbine combustor capable of uniformly and stably supplying combustion air in order to further reduce toxic waste in exhaust gas. With the goal.

It is a further object of the present invention to provide a gas turbine combustor that can effectively utilize limited cooling air and sufficiently cope with the heat load of the combustion gas of the transition piece.

It is still another object of the present invention to provide a gas turbine combustor which can maintain a stable state of a transit piece without any trouble during a cooling operation.

[Configuration of the invention]

(Means for Solving the Problems) The gas turbine combustor according to the present invention is provided with a liner outer cylinder surrounding the outside of the liner inner cylinder to form a combustion air passage and formed in the liner inner cylinder. In a gas turbine combustor provided with a transition piece for guiding a combustion gas to a gas turbine, a sleeve for surrounding the outside of the transition piece is provided to form a cooling passage, and the cooling passage is provided at a predetermined distance from the sleeve. While placing a solid heat transfer enhancer arranged in a lattice on the transition piece, while drilling a hole in the transition piece along the axial direction with the heat transfer enhancer as the center, A hole is formed in the sleeve along the circumferential direction around the heat transfer enhancer.

(Operation) In the present invention having the above configuration, the compressed air flows separately into air for cooling the transition piece and combustion air for promoting the generation of combustion gas. The combustion air reacts with the cooling of the liner inner cylinder and the fuel to generate high-temperature combustion gas to drive the turbine. At this time, the air flowing from the outer periphery of the transition piece is perforated in the sleeve and jet-collides with the transition piece from the hole to cause the transition piece to perform impingement cooling.

The air that causes the transition piece to perform impingement cooling impinges on the heat transfer enhancer and disrupts its flow, thereby increasing the heat transfer coefficient and causing the sleeve and the transition piece to perform convective cooling.

Further, the heat transfer enhancer provided on the transition piece side has one end made free so as to cope with thermal expansion and contraction occurring during operation, and is formed in a solid shape to secure a larger heat transfer area.

As described above, the gas turbine combustor according to the present invention employs means for separately dividing combustion air and cooling air, so that uniform and stable air is guided to the head of the combustor. Can be.

In addition, the gas turbine combustor according to the present invention further enhances cooling by combining impingement cooling and convection cooling, so that the transition piece is sufficiently cooled even with limited cooling air. Therefore, it is possible to sufficiently protect against the heat load of the combustion gas.

Further, in the gas turbine combustor according to the present invention, since one end of the heat transfer enhancer is a free end and the heat transfer enhancer is solid, there is no collision with the sleeve due to thermal expansion and contraction during operation. Thus, damage accidents can be prevented, and more effective cooling can be performed by securing a more solid heat transfer area.

Hereinafter, an embodiment of a gas turbine combustor according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a gas turbine combustor according to the present invention, in which a gas turbine combustor 1 is provided between a compressor 2 and a gas turbine 4 driving a generator 3, and a compressor 2
Combustor outer casing 5 defining discharge chamber from
And between the combustor inner casing 6. The combustor outer casing 5 and the combustor inner casing 6
The compressor 2 and the casings of the gas turbine 4 are integrally or integrally connected, and a plurality, for example, ten or fourteen, of the gas turbine combustors 1 are arranged in a circumferential direction in the outer casing 5 of the combustor. .

The gas turbine combustor 1 includes a liner outer cylinder (combustor flow sleeve) 11 and a liner inner cylinder 12
(Combustor liner) and a double cylinder structure, and its annular space is defined as a combustion air passage 11a. A combustion chamber 12a is defined in the liner inner cylinder 12, and the combustion chamber 1a
Fuel and combustion air are supplied into 2a, mixed, and provided for combustion. The combustor inner casing 6 is provided with a combustor head plate 16.
The fuel nozzle set 17 is attached to the.

On the other hand, a swirler 23 is provided at the tip of the liner inner cylinder 12, and the air flowing between the liner outer cylinder 11 and the inner cylinder 12 is given a strong swirling flow when passing through the air hole of the swirler 23. A transition piece 13 is attached to the rear end of the liner inner cylinder 12, and the outside of the transition piece 13 is surrounded by a sleeve 14 at a predetermined interval, and a cooling passage 14 is provided.
c is formed.

As shown in FIGS. 2 (A), 2 (B) and 2 (C), a large number of circular cooling holes 24 are formed in the sleeve 14.
The cooling air is guided from 24 and jetted toward the transition piece 13. Further, on the peripheral surface of the transition piece 13 on the side of the cooling passage 14c, a pellet-shaped or column-shaped heat transfer promoting body 15 for disturbing the cooling air from the cooling hole 24 is provided.

The heat transfer enhancer 15 has an end portion provided with a predetermined gap G between the sleeve 14 and the sleeve 14 in consideration of expansion and contraction and deformation of the sleeve 14 and the transition piece 13 due to combustion gas. Further, the heat transfer enhancer 15 is formed in a solid shape, and further increases the heat transfer area. Further, a plurality of circular film cooling holes 26 are formed in the transition piece 13 so that cooling air can flow in a film shape, and the cooling holes 26 are formed by cooling air ejected from the cooling holes 24 of the sleeve 14. Are arranged so that their relative positions are different so as not to blow through directly.

That is, as shown in FIG. 2 (A), the relative positional relationship between the cooling holes 24 formed in the sleeve 14 and the film cooling holes 26 formed in the transition piece 13, Around the body 15, a film cooling hole 36 is bored in the transition piece 13 along the axial direction,
Cooling holes 24 are formed in the sleeve 14 along the circumferential direction.

Further, the sleeve 14 and the transition piece 13 are supported by a front support 19 and a rear support 20,
Front support 19 is sleeve and transition piece
13 is fixed so as to be extendable in the gas turbine axial direction, and since the rear support 20 is difficult to surround with the sleeve 14, another impingement plate 27 and a heat transfer enhancer 15 are provided as shown in FIG. The transition piece support section is also configured to perform uniform cooling.

 Next, the operation of the present embodiment will be described.

The air compressed by the compressor 2 flows into an air chamber 21 formed by the combustor outer casing 5 and the combustor inner casing 6, from which a cooling passage 14a for cooling the transition piece 13 and a combustion gas are generated. The air flows separately from the combustion air passage 11a. Here, the compressor 2
Although the air discharged from flows in with high-frequency turbulence, it is greatly attenuated because the air chamber 21 has its rectifying effect,
It flows between the liner outer cylinder 11 and the inner cylinder 12, and flows into the combustion chamber 12 a of the inner cylinder 12 through the combustion air holes 22 formed in the inner cylinder 12.

Further, the air flowing between the liner outer cylinder 11 and the inner cylinder 12 flows into the combustion chamber 12a through an air hole provided in the swirler 23. When the air passes through the air holes of the swirler 23, a strong swirling flow is given to the air, so that the air and the fuel are mixed well in the combustion chamber 12a, and the combustion is stabilized. The high-temperature combustion gas burned in the combustion chamber 12a is guided by the transition piece 13 from the flow path having a circular cross section to the inlet of the gas turbine 3.

On the other hand, a part of the air flowing into the air chamber 21 is guided to the cooling passage 14c of the transition piece 13 for cooling. This cooling air is supplied to the sleeve 14 as shown in FIG.
Transition piece 13 from the large number of cooling holes 24
The transition piece 13 is subjected to impingement cooling by causing a jet collision. The flow of the cooling air obtained by impinging the surface of the transition piece 13 is disturbed by the heat transfer enhancer 15, and the heat transfer coefficient increases with the disturbance of the flow, so that the convective cooling of the transition piece 13 is further promoted. .

Next, the cooling air that has cooled the transition piece 13 passes through the film cooling hole 26 while flowing through the cooling passage 14c, flows in the form of a film along the inner surface of the transition piece 13, and performs film cooling. This film cooling protects the transition piece 13 from the thermal load of the combustion gas.

The cooling air obtained by film-cooling the transition piece 13 is mixed and diffused with the combustion gas, and the temperature of the combustion gas is lowered to meet the design conditions.

As described above, according to the present embodiment, fuel is formed by forming the combustion air passage 11a and the cooling passage 14c that guide the high-pressure air from the compressor separately to the combustion chamber 12a and the transition piece 13. Lean combustion can be performed stably, and as a result, it is possible to provide a gas turbine combustor that achieves low NOx in combustion exhaust gas and extremely low CO and UHC emissions. Further, since the air flow rate is constant and uniformly distributed in the combustor 1, unstable pressure fluctuations in the combustor 1 are eliminated, and the liner outer cylinder 11, the transition piece 13, and the front and rear support 19, 20, etc. Cracking and wear are significantly reduced, and reliability is improved. Since the distribution of the cooling air to the liner outer cylinder 11 and the transition piece 13 is stable and no deviation or the like occurs, the phenomenon such as insufficient cooling does not occur partially, and the reliability can be further improved.

Further, by providing the heat transfer enhancer 15 in the cooling passage 14c, the turbulence is given to the cooling air to increase the heat transfer coefficient, so that convection cooling can be performed more effectively.

Further, since the heat transfer promoting body 15 has an end facing the sleeve 14 side as a free end, heat expansion and contraction generated during operation is reduced.
Without colliding with the sleeve 14, damage accidents can be prevented.

Further, since the heat transfer promoting body 15 is formed in a solid shape, the heat transfer area can be further increased, and effective cooling can be performed.

FIGS. 4 (A), (B) and (C) show another embodiment of the sleeve, and the sleeve 14 shown in FIG. 4 (A) is constituted by combining split half halves 14a and 14b. A plurality of metal fittings 18 for connection and fixing are provided on the divided surfaces of the half-split bodies 14a and 14b. FIG. 4 (B) shows that the metal fitting 18a for connecting and extending extends over substantially the entire length of the connecting portion. 14a and 14b are connected. The connection portion can be connected by welding, bolts, or the like, and both flanges 32 of the half-split bodies 14a and 14b can be connected and fixed by a plurality of stopper plates 29 as shown in FIG. 4 (C). As shown in FIG. 5 (A), the stopper plate 29 may have a spring effect to elastically hold both flanges 32. Further, as shown in FIG. 5 (B), irregularities may be formed on the contact surfaces of the flanges 32 so as to prevent the connection portions from shifting. The half-split bodies 14a and 14b can be positioned by pins (not shown).

Also, the sleeve 14 and the transition piece 13 are
As shown in FIG. 6 (A), a slide portion 33 may be fixed to the end of the sleeve 14 so as to allow thermal expansion deformation due to the combustion gas. , Or on the turbine side or between them, and the number thereof may be plural. As shown in FIG. 6B, instead of the slide portion 33, the end of the sleeve 14 may be bent to form a bellows 30, and the bellows 30 may absorb the thermal expansion deformation caused by the combustion gas. .

Further, the shape of the heat transfer promoting body 15 may be conical as shown in FIG. 7 (A) in addition to the columnar shape shown in FIG. Anything that induces turbulence so as to supply the pressure may be used. Further, by providing the film cooling holes 26 formed in the transition piece 13 at an angle as shown in FIG. 7 (B), the film cooling efficiency can be further increased. It may be a long hole, and may be larger in diameter than the cooling hole 24 of the sleeve 14. The thicknesses of the sleeve 14 and the transition piece 13 are not limited to those in the above-described embodiment, and the same effect can be obtained even if the sleeve 14 side is made thicker or the same. In addition, the cooling holes 24 and the heat transfer enhancers 15 of the sleeve 14 are not limited to those in the above-described embodiment, and their arrangement and intervals may not be constant. The heat transfer enhancer 15 may not necessarily be attached to the transition piece 13 but may be attached to the sleeve 14 or to both of them.

FIG. 8 (A) shows another embodiment of the liner outer cylinder. As shown in FIG. 8, the front end of the liner outer cylinder 11 is formed to be curved in the outer peripheral direction, and a combustion air inlet guide 31 is provided. By this inlet guide 31, the inflow of air into the combustion air passage 11a can be made uniform, and in particular, the combustion state can be stabilized. FIG. 8 (B) shows the inlet guide 31 formed into a hollow pipe shape and welded to the liner outer cylinder 11. The inlet guide 31 serves both as a guide member and a reinforcing member. In addition to the function of the entrance guide 31, the strength can be increased. In the case where the liner outer cylinder 11 and the transition piece 13 are close to each other, FIG.
If the corner of the end face of the transition piece 13 is cut off as shown in FIG. 3B, the inflow of air can be further equalized. As shown by solid lines in FIGS. 9 and 10, the circumferential distribution of air and the circumferential distribution of fuel-air ratio can be made uniform.

〔The invention's effect〕

As described above, in the gas turbine combustor according to the present invention, the air flowing through the liner inner cylinder and the transition piece is stable and evenly flows, so that each part is maintained at a healthy temperature, and combustion instability is reduced. Absent. As a result, lean (low temperature) combustion near the flammable limit can be sustained stably, reducing NOx and reducing unburned component (CO, UHC) emissions, increasing combustion efficiency and increasing gas turbine combustion. The efficiency of the vessel can be improved.

Further, since combustion instability can be prevented, damage to the combustor components is eliminated, and a gas turbine combustor with significantly improved reliability can be provided.

In the gas turbine combustor according to the present invention,
A heat transfer enhancer is provided in the cooling passage to disturb the flow of cooling air and further promote convection cooling.In combination with impingement cooling, the transition piece can also be used to generate heat from the combustion gas even with limited cooling air. It is possible to sufficiently protect against a load.

Furthermore, in the gas turbine combustor according to the present invention, since the end of the heat transfer promoting body facing the sleeve side is a free end and thermal expansion and contraction occurring during operation is taken into account, damage accidents due to collision with the sleeve are avoided. Can be prevented.

At this time, since the heat transfer promoting body is formed in a solid shape and the heat transfer area is further increased, it is possible to prevent a damage accident and perform an effective cooling operation with dust.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a gas turbine combustor according to an embodiment of the present invention, and FIGS. 2 (A), (B) and (C) show a transition piece cooling structure, and FIG. FIG. 2 (A) is an enlarged view, FIG. 2 (B) is a sectional view taken along line BB of FIG. 2 (A), FIG. 2 (C) is a sectional view taken along line CC of FIG. 2 (A), and FIG. Sectional view showing rear support, fourth
FIGS. 5A, 5B and 5C are perspective views showing another embodiment of the sleeve, FIGS. 5A and 5B are sectional views showing a joint portion of the sleeve, and FIG. 6A. , (B) is a cross-sectional view showing the transition piece and the end of the sleeve, and FIG.
(B) is a cross-sectional view showing another embodiment of the transition piece cooling structure, FIGS. 8 (A) and (B) are cross-sectional views showing another embodiment of the tip of the liner outer cylinder, and FIG. 9 is a combustor. Explanatory diagram showing the circumferential distribution of air at the inlet of the flow sleeve, FIG.
FIG. 10 is an explanatory view showing a circumferential distribution of a fuel-air flow ratio (fuel-air ratio) in a combustor liner, FIG. 11 is a partial cross-sectional view showing a conventional gas turbine combustor, and FIG. It is a front view which shows the connection part with the turbine of the transition piece shown in the figure. DESCRIPTION OF SYMBOLS 1 ... Gas turbine combustor, 2 ... Compressor, 4 ... Generator, 11 ... Liner outer cylinder, 11a ... Combustion air passage, 12
…… Liner inner tube, 13… Transition piece, 14…
... Sleeve, 14c ... Cooling passage, 15 ... Heat transfer enhancer, 2
4 ... cooling holes, 26 ... film cooling holes.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Fukuo Maeda 2-4 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Keihin Plant (56) References JP-A-61-231330 (JP, A) JP-A-63-15011 (JP, A) JP-A-58-72822 (JP, A) JP-A-63-131924 (JP, A) Full-scale application Sho-61-154450 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) F23R 3/06 F02C 7/18 F23R 3/42

Claims (1)

(57) [Claims] A liner outer cylinder surrounding the outside of a liner inner cylinder is provided to form a combustion air passage, and a transition piece for guiding combustion gas generated in the liner inner cylinder to a gas turbine is provided. In the gas turbine combustor, a sleeve for surrounding the outside of the transition piece is provided to form a cooling passage, and the cooling passage is spaced a predetermined distance from the sleeve,
And, while providing the solid-state heat transfer promoting body in the form of a lattice in the transition piece, a hole is formed in the transition piece along the axial direction around the heat transfer promoting body, and the heat transfer promoting body is provided. A gas turbine combustor characterized in that a hole is formed in the sleeve along the circumferential direction around the center.