JP7336848B2 - Combustion device - Google Patents

Description

The present invention relates primarily to combustion devices used in gas turbine engines.

2. Description of the Related Art In recent years, gas turbine engines that use hydrogen as fuel have been proposed for the realization of a so-called low-carbon society. However, fuel with a high burning rate, such as fuel containing hydrogen, tends to generate NOx due to its high combustion temperature. In addition, when burning fuel with a high burning velocity, flashback phenomenon is likely to occur in which the flame generated in the combustion chamber returns to the burner side.

As a combustion device for realizing low NOx combustion and flashback prevention while using a highly reactive gas such as hydrogen as fuel, a plurality of annular members for injecting fuel are arranged concentrically, and each annular member The fuel is dispersed and injected in the radial direction from a large number of fuel injection holes provided in the fuel injection hole, and the air is flown toward the combustion chamber in a direction substantially orthogonal to the fuel injected from the fuel injection hole. A technique using an injector has been proposed (see, for example, Patent Document 1). According to the combustion apparatus having such a structure, multi-point injection of fuel suppresses the occurrence of localized high-temperature combustion, so low NOx combustion becomes possible. Furthermore, the occurrence of the flashback phenomenon is suppressed by supplying air toward the combustion chamber side of the radially injected fuel.

WO2015/182154

However, in the combustion apparatus disclosed in Patent Literature 1, the fuel injector as a whole has a shape close to a flat plate shape, so combustion vibration is likely to occur.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to achieve low NOx combustion, prevent flashback, and suppress combustion vibration in a combustion apparatus that uses fuel with a high burning velocity, in order to solve the above problems.

In order to solve the above problems, the combustion device according to the present invention includes:
a combustion cylinder forming a combustion chamber inside;
a fuel injector having a plurality of concentrically arranged annular fuel injection units for injecting fuel gas and air into the combustion chamber;
Each fuel injection unit
an annular fuel injection member having a plurality of fuel injection holes arranged side by side in the circumferential direction and opening to the outer peripheral surface and/or the inner peripheral surface;
an annular air guide member having a plurality of air guide grooves for guiding air to the fuel gas injected from each fuel injection hole of the annular fuel injection member;
has
A plurality of radially extending circumferential isolation walls isolating the gas passages of at least one of said annular fuel injection units at equal intervals in the circumferential direction, and radially isolating between at least two adjacent said annular fuel injection units. , and at least one of the circumferentially extending radial isolation walls.

According to this configuration, by providing a plurality of annular fuel injection members and annular air guide members, low NOx combustion and flashback prevention can be realized. Furthermore, the movement of the flame is restricted by providing the isolation wall that isolates the annular fuel injection units in the circumferential direction or the radial direction, thereby suppressing the occurrence of combustion oscillation.

In one embodiment of the present invention, at least the annular fuel injection unit arranged on the outermost circumference may be provided with a plurality of the circumferential separation walls. According to this configuration, the combustion oscillation can be effectively suppressed by restricting the movement of the flame in the circumferential direction in the outermost annular fuel injection unit where the combustion oscillation is most likely to occur.

In one embodiment of the present invention, the circumferential separation wall and the radial separation wall may be provided downstream of at least the fuel injection holes. According to this configuration, combustion oscillation can be effectively suppressed by providing the isolation wall in the portion where the flame exists.

As described above, according to the combustion apparatus of the present invention, low NOx combustion and flashback prevention can be achieved, and combustion oscillation can be suppressed.

1 is a block diagram showing a schematic configuration of a gas turbine engine to which a fuel injector according to one embodiment of the invention is applied; FIG. It is a sectional view showing a combustion device concerning one embodiment of the present invention. 3 is a perspective view of an example fuel injector for use in the combustion device of FIG. 2; FIG. 4 is a front view showing an enlarged part of the fuel injector of FIG. 3; FIG. Figure 3 is a cross-sectional view of an annular fuel injection block of a fuel injector used in the combustion system of Figure 2;

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments according to the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments.

FIG. 1 shows a schematic configuration of a gas turbine engine (hereinafter simply referred to as "gas turbine") GT to which a combustion apparatus according to an embodiment of the present invention is applied. The gas turbine GT compresses the introduced air with the compressor 1 and guides it to the combustion device 3, injects fuel into the combustion device 3 and burns it, and drives the turbine 5 with the obtained high-temperature and high-pressure combustion gas G. . The combustion device 3 is, for example, a can-type combustion device that is annularly arranged around the axis of the gas turbine GT. A turbine 5 is connected to the compressor 1 via a rotating shaft 7 , and the compressor 1 is driven by the turbine 5 . The output of this gas turbine GT drives a load L such as an aircraft rotor or a generator. In the following description, the compressor 1 side in the axial direction of the gas turbine GT is called "front side", and the turbine 5 side is called "rear side".

As shown in FIG. 2, the combustion device 3 includes a combustion cylinder 13 forming a combustion chamber 11 inside, and a fuel injection device for injecting fuel gas (hereinafter simply referred to as "fuel") F and air A into the combustion chamber 11. A vessel 15 is provided. The fuel injector 15 is attached to the top portion (most upstream portion) 13 a of the combustion cylinder 13 . A flame is formed in the combustion chamber 11 by igniting the fuel F and the air A injected from the fuel injector 15 with the ignition device P provided in the combustion cylinder 13 . The combustion cylinder 13 and the fuel injector 15 are concentrically accommodated in a substantially cylindrical housing H that serves as the outer cylinder of the combustion device 3 .

In this embodiment, the combustion device 3 is configured as a counterflow type in which the air A and the combustion gas G flow in opposite directions. That is, the combustion device 3 has an air introduction passage 19 formed between the housing H, the combustion cylinder 13, and the support cylinder 17 cylindrically extending forward from the combustion cylinder 13. The air introduction passage 19 is , guides the air A compressed by the compressor 1 (FIG. 1) in a direction opposite to the flow direction of the combustion gas G in the combustion chamber 11 . The combustion device 3 may be of an axial flow type in which the air A and the combustion gas G flow in the same direction. A plurality of air introduction holes 21 are provided side by side in the circumferential direction at the front end portion of the peripheral wall of the support tube 17 . The air A sent through the air introduction passage 19 passes through the air introduction hole 21, is introduced into the air supply passage 23 formed inside the support cylinder 17, and flows rearward, that is, in the direction of the combustion chamber 11. Sent.

As shown in FIG. 3, fuel injector 15 comprises a plurality of annular fuel injection units 25 . As shown in FIG. 4 , each annular fuel injection unit 25 has an annular fuel injection member 27 and an annular air guide member 29 . The annular fuel injection member 27 has a plurality of fuel injection holes 31 arranged side by side in the circumferential direction and opening to the outer peripheral surface and/or the inner peripheral surface. In the illustrated example, the annular fuel injection member 27 has a plurality of outer fuel injection holes 31A opening on the outer peripheral surface and a plurality of inner fuel injection holes 31B opening on the inner peripheral surface. Fuel F is injected from each fuel injection hole 31 .

The annular air guide member 29 is an annular member having a plurality of air guide grooves 33 for guiding air A to the fuel F injected from each fuel injection hole 31 of the annular fuel injection member 27 . In the illustrated example, an outer annular air guide member 29A that is disposed radially outward of the annular fuel injection member 27 and guides air to the fuel injected from each of the outer fuel injection holes 31A; An inner annular air guide member 29B is disposed radially inward of the inner annular air guide member 29B for guiding air to the fuel injected from each of the inner fuel injection holes 31B. In this example, between the radially adjacent annular fuel injection units 25, 25, the inner annular air guide member 29B of the outer annular fuel injection unit 25 and the outer annular air guide member 29B of the inner annular fuel injection unit 25 are arranged. 29A are integrally formed.

In this embodiment, as shown in FIG. 3, three annular fuel injection units 25 having different diameters are arranged concentrically with each other and concentrically with the combustion device 3 (FIG. 2). The plurality of annular fuel injection units 25 are supported by a cylindrical support cover 35 that covers the outermost periphery thereof. In the following description, the three annular units 25 may be distinguished from the first annular fuel injection unit 25A to the third annular fuel injection unit 25C in order from the outer peripheral side as necessary. Note that the number of annular fuel injection units 25 is not particularly limited as long as it is two or more.

As shown in FIG. 2 , the combustion device 3 has a plurality of fuel supply passages capable of supplying fuel F to the annular fuel injection member 27 of each annular fuel injection unit 25 of the fuel injector 15 . The fuel injector 15 is provided with a fuel supply header 39 extending from the center of the air supply passage 23 to the rear of the housing H. As shown in FIG. The fuel supply mother pipe 39 and each annular fuel injection unit 25 are connected by branch fuel supply pipes 41 that branch independently of each other. The fuel supply mother pipe 39 has a multi-tube structure (double-tube structure) in which two cylindrical pipes are concentrically stacked. The inner space of the inner fuel supply pipe and the inner space of the branch fuel supply pipe 41 communicating therewith form a first fuel supply passage 43, and the space between the inner and outer fuel supply pipes and the branch communicating therewith. An inner space of the fuel supply pipe 41 forms a second fuel supply passage 45 . Fuel is introduced from a fuel introduction system IS into each of the fuel supply paths 43 and 45 in the fuel supply mother pipe 39 .

In this embodiment, the fuel that has passed through the first fuel supply passage 43 is supplied to two annular fuel injection units 25B and 25C arranged on the inner diameter side of the plurality of annular fuel injection units 25, and is supplied to the second fuel supply. The fuel F that has passed through the passage 45 passes through one branch fuel supply pipe 41 connected to the second fuel supply passage 45, and flows through one annular fuel injection unit 25 arranged on the outermost diameter side of the plurality of annular fuel injection units 25 It is supplied to the fuel injection unit 25A.

The multi-pipe structure of the fuel supply mother pipe 39 is not limited to the example of FIG. 2 as long as a plurality of mutually independent fuel supply passages can be formed using a plurality of pipes. For example, a multi-pipe structure may be employed in which a plurality of smaller fuel supply pipes having the same diameter extend in parallel in one large-diameter mother pipe.

With such a fuel supply structure, fuel is supplied to the annular fuel injection unit 25 that supplies fuel in response to changes in the output of the gas turbine GT from low load (partial load) to high load (rated load). A corresponding staging combustion is made possible by dividing the fuel into an annular fuel injection unit 25 that does not have one. As in this embodiment, when the fuel is dispersed and injected into a large number of fuel injection holes 31 of the plurality of annular fuel injection units 25 of the fuel injector 15, all the annular fuel injection units 25 uniformly disperse the fuel. Rather than changing the supply amount, it is effective for stable and low NOx combustion to respond to load fluctuations by selecting which annular fuel injection unit 25 is activated and which is not. However, the structure for supplying fuel to the fuel injector 15 is not limited to this example.

As shown in FIG. 5, the annular fuel injection member 27 has a substantially rectangular cross-sectional shape, and the rear wall 27a facing the combustion chamber 11 is arranged perpendicular to the axial center C direction. A fuel introduction chamber 47 that is an annular space is formed inside the annular fuel injection member 27 . In the illustrated example, the fuel injection hole 31 penetrates the outer peripheral wall 27b and the inner peripheral wall 27c of the annular fuel injection member 27 in the radial direction R, and is annular with the fuel introduction chamber 47. It is provided as a through hole that communicates with the outside of the fuel injection member 27 . The fuel is injected from the fuel injection hole 31 after being supplied to the fuel introduction chamber 47 from the fuel supply passage (the branched fuel supply pipe 41 in this example) connected to the front wall 27 d of the annular fuel injection member 27 . However, the internal structure of the annular fuel injection member 27 is not limited to this example. The fuel injection hole 31 may be inclined in the direction of the axis C with respect to the radial direction R within a range of -10° to +80°. Here, the inclination angle when the fuel injection hole 31 is inclined upstream in the axial direction C with respect to the radial direction R is assumed to be a negative inclination angle, and the fuel injection hole 31 is inclined downstream in the axial direction C with respect to the radial direction R. The tilt angle when 31 tilts is defined as a positive tilt angle.

Fuel injected from the annular fuel injection member 27 is premixed with air guided by the annular air guide member 29 and injected into the combustion chamber 11 . The annular air guide member 29 is arranged on the front side of the fuel injection hole 31 of the annular fuel injection member 27, that is, on the upstream side in the direction in which the air A flows. Thus, by providing the annular air guide member 29 so as to guide the air A in the direction of the axis C from the upstream side of the fuel F injected from each fuel injection hole 31, the fuel F and the air A Since they intersect in substantially orthogonal directions, the fuel F and the air A can be uniformly mixed.

Each annular fuel injection member 27 may have only one of the outer fuel injection holes 31A and the inner fuel injection holes 31B. In that case, the annular fuel injection unit 25 includes an annular fuel injection member 27 and an outer annular air guide member 29A or an inner air guide member 29A corresponding to the outer fuel injection hole 31A or the inner fuel injection hole 31B formed in the annular fuel injection member 27. Annular air guide member 29B.

In this embodiment, as shown in FIG. 2 , the fuel injector 15 is provided with a circumferential isolation wall 51 and a radial isolation wall 53 . The circumferential isolation wall 51 is a radially extending flat plate member that isolates the gas passages 55 of the annular fuel injection unit 25 at equal intervals in the circumferential direction. A plurality (six in this example) of the circumferential separation walls 51 are provided. In this example, the circumferential isolation wall 51 is provided only in the outermost first annular fuel injection unit 25A. In this specification, the gas passage 55 of the annular fuel injection unit 25 means a space in the annular fuel injection unit 25 through which the air A, the fuel gas F, or a mixture of these flows. It refers to the area through which these gases pass up to chamber 11 .

The radial separating wall 53 is a circumferentially extending plate-like member, in other words, a cylindrical member that radially separates the two adjacent annular fuel injection units 25 . In this example, one radial separation wall between the first annular fuel injection unit 25A and the second annular fuel injection unit 25B and between the second annular fuel injection unit 25B and the third annular fuel injection unit 25C. 53 are provided.

The circumferential separation wall 51 suppresses combustion oscillations by restricting the movement of the flame in the annular fuel injection unit 25 in the circumferential direction. The circumferential separating wall 51 may be provided not only in the first annular fuel injection unit 25A but also in at least one annular fuel injection unit 25 among the plurality of annular fuel injection units 25 . However, since the movement of the flame in the circumferential direction is most likely to occur in the outermost annular fuel injection unit 25, at least the first annular fuel injection unit 25A is provided with a plurality of circumferential isolation walls 51, thereby efficiently generating combustion oscillations. can be suppressed.

The radial separation wall 53 suppresses combustion oscillations by restricting flame movement between adjacent annular fuel injection units 25 . The radial separation wall 53 does not necessarily have to be provided between all the annular fuel injection units 25 as in the present embodiment, and may be provided between at least two adjacent annular fuel injection units 25 .

Further, by providing both the circumferential separating wall 51 and the radial separating wall 53 in the fuel injector 15, the combustion oscillation can be suppressed very effectively. If at least one of the isolation walls 53 is provided, the effect of suppressing combustion oscillation can be obtained.

As shown in FIG. 5 , the circumferential isolation wall 51 and the radial isolation wall 53 are provided downstream of at least the fuel injection holes 31 . In the illustrated example, the circumferential isolation wall 51 and the radial isolation wall 53 protrude downstream from the rear surface of the annular air guide member 29 . Specifically, the circumferential isolation wall 51 includes an outer peripheral portion 51a in contact with the outer peripheral wall of the annular fuel injection member 27, an inner peripheral portion 51b in contact with the inner peripheral wall of the annular fuel injection member 27, and an outer peripheral portion 51a and an inner peripheral portion. A connecting portion 51 c extends radially to connect the outer peripheral portion 51 a and the inner peripheral portion 51 b behind (downstream side) of 51 b and is in contact with the rear wall 27 a of the annular fuel injection member 27 . In other words, the circumferential isolation wall 51 is formed in a substantially U-shape as viewed from the side and includes an outer peripheral portion 51a, an inner peripheral portion 51b, and a connecting portion 51c.

In this manner, by providing the circumferential isolation wall 51 and the radial isolation wall 53 at least downstream of the fuel injection holes 31, that is, in a portion where flame exists, combustion oscillation can be effectively suppressed. .

According to the combustion device 3 according to the present embodiment described above, by providing the plurality of annular fuel injection members 27 and annular air guide members 25, low NOx combustion and flashback prevention can be realized. Furthermore, the isolation walls 51 and 53 that isolate the annular fuel injection unit 25 in the circumferential direction or the radial direction restrict the movement of the flame, thereby suppressing the occurrence of combustion oscillation.

In this embodiment, a can-type combustion apparatus has been described as an example, but the above configuration can also be applied to other types of combustion apparatus, for example, an annular-type combustion apparatus.

As described above, preferred embodiments of the present invention have been described with reference to the drawings, but various additions, changes, or deletions can be made without departing from the scope of the present invention. Accordingly, such are also included within the scope of this invention.

3 Combustion device 11 Combustion chamber 13 Combustion cylinder 15 Fuel injector 25 Annular fuel injection unit 27 Annular fuel injection member 29 Annular air guide member 29A Outer annular air guide member 29B Inner annular air guide member 31 Fuel injection hole 31A Outer fuel injection hole 31B Inner fuel injection hole 33 Air guide groove 51 Circumferential isolation wall 53 Radial isolation wall 55 Gas passage of annular fuel injection unit

Claims (4)

a combustion cylinder forming a combustion chamber inside;
a fuel injector having a plurality of concentrically arranged annular fuel injection units for injecting fuel gas and air into the combustion chamber;
with
Each annular fuel injection unit is
an annular fuel injection member having a plurality of fuel injection holes arranged side by side in the circumferential direction and opening to the outer peripheral surface and/or the inner peripheral surface;
an annular air guide member having a plurality of air guide grooves for guiding air to the fuel gas injected from each fuel injection hole of the annular fuel injection member;
has
The fuel injector includes a plurality of radially extending circumferential isolation walls that equally circumferentially isolate the gas passages of at least one of the annular fuel injection units and between at least two adjacent annular fuel injection units. at least one of the circumferentially extending radial isolation walls radially isolating the
Combustion device. a combustion cylinder forming a combustion chamber inside;
a fuel injector having a plurality of concentrically arranged annular fuel injection units for injecting fuel gas and air into the combustion chamber;
with
Each annular fuel injection unit is
an annular fuel injection member having a plurality of fuel injection holes arranged side by side in the circumferential direction and opening to the outer peripheral surface and/or the inner peripheral surface;
An annular air guide having a plurality of air guide grooves disposed upstream of the fuel injection holes in the air flow direction and guiding air to the fuel gas injected from the fuel injection holes of the annular fuel injection member. a member;
has
A plurality of radial isolation walls protruding downstream in the air flow direction from the annular air guide member to isolate the gas passages of the at least one annular fuel injection unit at equal intervals in the circumferential direction. and at least one of circumferentially extending radial separation walls projecting downstream from the annular air guide member to radially separate at least two adjacent annular fuel injection units. comprising
Combustion device. 3. The combustion apparatus according to claim 1, wherein a plurality of said circumferential isolation walls are provided at least in said annular fuel injection unit disposed on the outermost periphery. The combustion device according to any one of claims 1 to 3,
When the circumferential separation wall is provided, the circumferential separation wall is provided downstream of at least the fuel injection hole in the air flow direction,
In the combustion device, when the radial separation wall is provided, the radial separation wall is provided at least downstream of the fuel injection hole.

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