JPH10220760A - Method and structure of supplying air to gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a sufficient cooling of a scroll and moreover, a reduction in pressure loss. SOLUTION: A flow straightening means such as flow straightening body 1 is provided at an outlet D1 of a diffuser D to remove a spiral component applied by a compressor from air for combustion while a flow straightening cover is arranged to cover the outer circumferences of the rear and inside of a scroll S and at a specified interval. Thus, after the removal of spiral components applied by the compressor at the outlet D1 of the diffuser, the air for combustion is supplied to a gas turbine combustion device C along the outer circumference of the scroll S at a flow velocity enough to allow the cooling of the scroll S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and a structure for supplying air to a gas turbine combustor. More specifically, the present invention relates to a method and an air supply structure for supplying air to a gas turbine combustor while sufficiently cooling a scroll and reducing pressure loss.

[0002]

2. Description of the Related Art In a medium-sized or small-sized gas turbine, combustion gas discharged from a combustor C is supplied to the turbine by a snail-shaped scroll S as shown in FIGS. Since the combustion gas flowing inside the scroll S has a temperature of a hundred thousand degrees, a part of the combustion air (hereinafter simply referred to as air) supplied to the combustor C through the outer periphery of the scroll S is generated. Is sprayed into the scroll S from an injection hole (not shown) formed in the scroll S, an air film is formed on the inner wall of the scroll S by the ejected air, and the film of the inner wall of the scroll S is cooled by the film. Thus, burning of the inner wall of the scroll S by the combustion gas is prevented.

[0003] However, since this air is pressurized by the centrifugal compressor and then introduced to the outer periphery of the scroll S, the introduced air has a swirl component given by the centrifugal compressor (see FIG. 1). 5 arrow j, k, l). Therefore, the air supplied to the outer periphery of the scroll S does not flow along the outer periphery of the scroll S as shown in FIG. 4, and the inner wall of the housing H forming the outer periphery of the gas turbine located outside the scroll S. Flows along. That is, the air flows from point b to point b ′ in FIG.
Peeling occurs on the outer periphery of the scroll S rear surface (point c in FIG. 4) and the inner periphery of the scroll S (point d in FIG. 4). As a result, there is a problem that the cooling of the portion becomes insufficient and the portion is burnt.

Further, as shown in FIG. 5, since the height w of the scroll S in the direction of the engine rotation axis decreases in order from the fb portion to the ae portion, the air flowing in with a turning component is reduced. Flows toward the ae portion having less resistance. As a result, most of the air flows into the combustor C from the point i in FIG. 5 (see the arrow 1 in FIG. 5). As described above, when the air flowing into the combustor C is concentrated at one location, the flow velocity of the air entering the combustion chamber increases, and the air changes direction at the high flow velocity, so that a large pressure loss occurs. . As a result, there is also a problem that a desired combustion cannot be performed, resulting in a decrease in engine output and a decrease in efficiency.

Furthermore, since a part of the air to the combustor C is bypassed and used for film cooling, the combustion air during the combustion tends to be insufficient, resulting in an increase in nitrogen oxides. is there.

[0006] The specification of Japanese Utility Model Registration No. 30012224 describes that in order to uniformly supply air to a combustor C of a gas turbine having such a scroll structure, a combustor C is provided.
There is proposed a gas turbine combustor C provided with a rectifying means for reducing pressure loss near an open end of an air flow path to a combustion chamber (see FIG. 6). The cooling of S is not disclosed or suggested.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is directed to a method of supplying air to a gas turbine combustor while sufficiently cooling a scroll and having a small pressure loss. It aims to provide a supply structure.

[0008]

The method of supplying air to a gas turbine combustor according to the present invention eliminates swirling components imparted by a compressor at the outlet of a diffuser from combustion air from the combustor air. It is characterized in that air is supplied to the gas turbine combustor while flowing along the outer periphery of the scroll at a flow rate at which the scroll can be cooled.

In the method for supplying air to a gas turbine combustor according to the present invention, it is preferable that the combustion air is provided along the outer periphery of the scroll while imparting a swirling component in a direction opposite to the swirling direction of the compressor and the turbine.

On the other hand, a first embodiment of the structure for supplying air to a gas turbine combustor according to the present invention is provided with a rectifying means at an outlet of a diffuser for removing swirling components given by a compressor from combustion air. It is characterized by the following.

A second embodiment of the structure for supplying air to the gas turbine combustor according to the present invention is characterized in that a rectifying cover is provided to cover the outer periphery of the rear surface and the inner periphery of the scroll at predetermined intervals.

In a third aspect of the air supply structure for a gas turbine combustor according to the present invention, a rectifying means for removing a swirling component given by a compressor from combustion air is provided at an outlet of a diffuser, and a scroll is provided. A rectifying cover is provided to cover the back outer periphery and the inner outer periphery at predetermined intervals.

In this case, the interval is adjusted so that the combustion air passing therethrough has a speed at which desired cooling can be performed on the scroll. The air to the gas turbine combustor of the present invention is also adjusted. In the supply structure, it is preferable that a plurality of swirling component imparting members, for example, a plurality of vanes, which impart a swirling component in a direction opposite to the swirling direction of the compressor and the turbine to the combustion air are provided in the rectifying cover. .

[0014]

According to the present invention, the scroll can be sufficiently cooled while reducing the pressure loss from the diffuser to the combustor. Therefore, the film cooling which has been conventionally performed by the scroll becomes unnecessary. Further, since film cooling is not required, there is no shortage of combustion air at the time of combustion, so that generation of nitrogen oxides is suppressed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments with reference to the accompanying drawings, but the present invention is not limited to only such embodiments.

An essential part of an embodiment of an air supply structure (hereinafter simply referred to as a supply structure) K used in a method for supplying air to a gas turbine combustor C of the present invention is shown in FIG. FIG. 2 is a front view (view from the turbine side).

[0017] The feed structure K, as shown in FIGS. 1 and 2, a straightening member 1 disposed on the outlet D ₁ of the diffuser D, scroll S to air flow in the conventional structure is peeled off
A rectifying cover 2 disposed on an outer peripheral portion;
And a vane 3 disposed therein.

The straightening body 1 is formed to have a curved surface capable of removing a swirling component imparted to the air by the compressor and smoothly changing the direction of the air flow in the axial direction (see FIG. 3). Therefore, the swirling component of the air that has exited the diffuser D is removed. In addition, the air flow is rectifier 1
When the vehicle turns along the curved surface, the speed is reduced. Since the speed is smoothly reduced, the pressure loss due to the speed reduction is reduced. That is, the pressure recovery rate is higher than the conventional one. The shape of the rectifier 1 having such characteristics can be obtained, for example, by three-dimensionally analyzing the flow of this portion by a computer.

As shown in FIGS. 1 and 2, the rectifying cover 2 has a portion where the air flow has separated on the outer periphery of the scroll S, that is, the outer periphery of the scroll S rear surface and the scroll S.
It is arranged at a predetermined interval outside the inner periphery.
Since the rectifying cover 2 is disposed in such a positional relationship, the air whose turning component has been removed by the rectifying body 1 and whose direction has been changed in the axial direction flows along the inner wall of the housing H forming the outer periphery of the gas turbine. When the flow reaches the point b in FIG. 1, the direction is forcibly changed by the rectifying cover 2 and flows inward along the outer periphery of the scroll S, that is, flows inward without separating from the outer periphery of the scroll S. Are guided to the axis side of the gas turbine. In this case, by appropriately selecting the interval between the rectifying cover 2 and the outer periphery of the scroll S, the air flowing therebetween can be controlled to a flow velocity at which the scroll S can perform desired air cooling.

As shown in FIGS. 1 and 2, a vane 3 is provided in the rectifying cover 2. The direction of the vane 3 is adjusted so as to apply a swirling force to the air in a direction opposite to the swirling direction of the compressor and the turbine rotated in the same direction by the same axis. Because of this,
The air flows through the inside of the rectification cover 2 with a small scroll S cross-sectional area.
The scroll S flows from the -e portion toward the b-f portion having a large sectional area so as to surround the scroll S. That is, while the air flow velocity is appropriately controlled by the rectifying cover 2, the vane 3 forms a flow surrounding the scroll S from the ae portion having a small cross-sectional area to the bf portion having a large cross-sectional area. As a result, the entire scroll S is uniformly cooled, and air is evenly distributed to the air flow path 4 formed between the casing and the combustor C at the inlet of the combustor casing. Is also reduced.

As described above, according to this embodiment, the injection hole for cooling the film, which is conventionally provided in the scroll S, becomes unnecessary, and the structure of the scroll S is simplified. Further, since air for cooling the film is not required, and sufficient air for combustion is obtained, generation of nitrogen oxides is suppressed. Further, since the air supply to the combustor C is made uniform and the pressure loss during the supply is reduced, the desired combustion is performed and the engine output and the efficiency are not reduced. In addition, since the scroll S is sufficiently cooled, the life of the scroll S is extended.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to only the embodiments, and various modifications can be made. For example, the number of vanes provided on the rectifying cover is not limited to the illustrated example, and may be appropriately increased or decreased according to the size of the gas turbine.

[0023]

As described above, according to the present invention, the following excellent effects can be obtained.

(1) An injection hole for cooling a film, which is conventionally provided in a scroll, is not required, and the structure of the scroll is simplified. That is, scrolling can be reduced in cost.

(2) Air for cooling the film is not required, and sufficient air for combustion is obtained, so that generation of nitrogen oxides is suppressed.

(3) Since the air supply to the combustor is made uniform and the pressure loss during the supply is reduced, the desired combustion is performed and the engine output and the efficiency are reduced. Absent.

(4) Since the scroll is sufficiently cooled, the life of the scroll is extended.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a main part of an embodiment of an air supply structure for a gas turbine combustor according to the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a schematic diagram of a rectifier used in the embodiment.

FIG. 4 is an axial cross-sectional view of a main part of a conventional structure for supplying air to a gas turbine combustor.

FIG. 5 is a front view of the same.

FIG. 6 is a schematic perspective view of a gas turbine combustor proposed in Utility Model Registration No. 3001224.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rectifier 2 Rectifier cover 3 Vane 4 Air flow path K Air supply structure to combustor D Diffuser C Combustor S Scroll H Housing

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Makichi Kajita 1-1, Kawasaki-cho, Akashi-shi Kawasaki Heavy Industries, Ltd. Inside the Akashi Plant (72) Inventor Shinichi Oga 1-1-1, Kawasaki-cho, Akashi-shi Kawasaki Heavy Industries, Ltd. Inside the company's Akashi factory (72) Takanori Takashi Inventor 1-1, Kawasaki-cho, Akashi-shi Kawasaki Heavy Industries, Ltd. Inside the company's Akashi plant (72) Inventor Kawanami Tsukinami 1-1-1, Kawasaki-cho, Akashi-shi, Kawasaki Heavy Industries Inside the Akashi Plant (72) Inventor Makoto Goda 1-1, Kawasaki-cho, Akashi City Inside the Akashi Plant of Kawasaki Heavy Industries, Ltd.

Claims (8)

[Claims] At the outlet of a diffuser, a swirl component given by a compressor is eliminated from combustion air, and the combustion air is supplied to a gas turbine combustor along the outer periphery of the scroll at a flow rate capable of cooling the scroll. A method for supplying air to a gas turbine combustor. 2. The gas turbine combustor according to claim 1, wherein the combustion air is provided along the outer periphery of the scroll while giving a revolving component in a direction opposite to a revolving direction of the compressor and the turbine. Air supply method. 3. A structure for supplying air to a gas turbine combustor, wherein a rectifying means for removing a swirling component imparted by a compressor from combustion air is provided at an outlet of the diffuser. 4. A structure for supplying air to a gas turbine combustor, wherein a rectifying cover is provided to cover a rear outer periphery and an inner outer periphery of the scroll at predetermined intervals. 5. A rectifying cover disposed at an outlet of the diffuser for removing a swirling component given by a compressor from combustion air, and covering a rear outer circumference and an inner outer circumference of the scroll at predetermined intervals. An air supply structure for a gas turbine combustor, comprising: 6. The apparatus according to claim 4, wherein the predetermined interval is adjusted so that the combustion air passing therethrough has a speed capable of achieving a desired cooling for the scroll. Air supply structure to gas turbine combustor. 7. A swirl component providing member for providing a swirl component in a direction opposite to a swirl direction of a compressor and a turbine to combustion air in the rectifying cover. Or an air supply structure to a gas turbine combustor according to 5. 8. A gas turbine comprising a structure for supplying air to a gas turbine combustor according to claim 3.