阅读说明：本技术 燃烧器及燃气轮机 (Combustor and gas turbine ) 是由 三浦圭祐 多田胜义 齐藤圭司郎 小金泽知己 苅宿充博 于 2020-01-24 设计创作，主要内容包括：燃烧器具备：多个燃料喷嘴(6),其沿喷嘴轴(An)方向延伸,并且朝向喷嘴轴(An)方向一侧喷射燃料；管板(3),其沿喷嘴轴(An)方向延伸,并且形成有供各燃料喷嘴(6)的前端部(6B)插入、且具有比前端部(6B)大的内径尺寸的多个空气孔(31)；以及台阶面(S3),其在前端部(6B)中的比朝向喷嘴轴(An)方向一侧的前端面(S1)靠另一侧的位置,从前端部(6B)的外周面即前端外周面(S2)沿针对喷嘴轴(An)而言的径向扩展。(The combustor is provided with: a plurality of fuel nozzles (6) that extend in the direction of a nozzle axis (An) and inject fuel toward one side in the direction of the nozzle axis (An); a tube plate (3) that extends in the direction of the nozzle axis (An) and that has formed therein a plurality of air holes (31) into which the tip end sections (6B) of the fuel nozzles (6) are inserted and that have a larger inner diameter than the tip end sections (6B); and a step surface (S3) that extends in the radial direction with respect to the nozzle axis (An) from the tip outer peripheral surface (S2), which is the outer peripheral surface of the tip end portion (6B), at a position on the other side of the tip end surface (S1) on the one side in the direction of the nozzle axis (An) in the tip end portion (6B).)

1. A burner, wherein the burner is provided with a burner body,

the combustor is provided with:

a plurality of fuel nozzles that extend in a nozzle axis direction and inject fuel toward one side in the nozzle axis direction;

a tube plate extending in the nozzle axis direction and formed with a plurality of air holes into which a tip end portion of each of the fuel nozzles is inserted and having a larger inner diameter size than the tip end portion; and

and a step surface that extends in a radial direction with respect to the nozzle shaft from a tip outer peripheral surface that is an outer peripheral surface of the tip portion, at a position on the other side of the tip portion than a tip end surface facing one side in the nozzle shaft direction.

2. The burner of claim 1,

a region of the tip outer peripheral surface on one side in the nozzle shaft direction with respect to the step surface extends from a radially outer side toward an inner side with respect to the nozzle shaft as going from the other side toward the one side.

3. The burner according to claim 1 or 2,

when the dimension of the region of the tip outer peripheral surface on the nozzle axial direction side of the step surface in the nozzle axial direction is x, and the dimension of the step surface in the radial direction is s, 5 < x/s < 20 is satisfied.

4. The burner according to claim 1 or 2,

the combustor has a plurality of turbulence projections formed with the step surface, the plurality of turbulence projections being arrayed at intervals in a circumferential direction with respect to the nozzle shaft, and projecting radially from the leading end outer circumferential surface.

5. The burner of claim 4,

when the dimension of the region of the tip outer peripheral surface on the nozzle axial direction side of the step surface in the nozzle axial direction is x, and the dimension of the step surface in the radial direction is s, 2 < x/s < 8 is satisfied.

6. A gas turbine, wherein,

the gas turbine is provided with:

a compressor that generates compressed air;

the combustor of any one of claims 1 to 5, mixing and combusting a fuel with the compressed air, thereby generating combustion gases; and

a turbine driven by the combustion gases.

Technical Field

The present invention relates to a combustor and a gas turbine.

The present application claims priority based on japanese patent application No. 2019-057307 applied in japan on 3, 25 and 2019, and the contents thereof are incorporated herein by reference.

Background

In power plants and chemical plants, in order to reduce carbon compounds discharged, there are increasing examples of using coal gasification as a fuel or operating a gas turbine with a fuel containing a large amount of hydrogen. On the other hand, it is also known that such a fuel has a higher combustion rate than conventional fuels, and therefore has a high possibility of backfiring (backfire). Accordingly, a burner that mixes fuel and air at a shorter distance and burns them has been proposed. As a specific example of such a burner, a burner described in patent document 1 below is known.

The combustor described in patent document 1 is a so-called integrated (cluster) combustor. The integrated burner has: the fuel injection device includes a plurality of fuel nozzles that inject fuel, and a plurality of air holes that are provided coaxially with the fuel nozzles on a downstream side of the fuel nozzles. With the injection of the fuel, a mixture gas of ambient air and the fuel is supplied to the downstream side through the air hole. By igniting the mixture gas, a plurality of small flames are formed on the downstream side of the air holes. Further, a protrusion for disturbing the flow is provided on the outer peripheral surface of the tip portion of the fuel nozzle. By disrupting the flow, mixing of fuel and air can be promoted.

Prior art documents

Patent document

Patent document 1: japanese patent No. 4894295

Disclosure of Invention

Problems to be solved by the invention

However, in the device described in patent document 1, since the projection for generating turbulence is provided at the tip end portion of the fuel nozzle, there is a possibility that the mixture gas stays in the vicinity of the tip end portion. If the mixture gas is retained, for some reason, the flame on the downstream side propagates upstream, or the ignition source flies upstream and comes into contact with the mixture gas, and a flame is formed in an unintended region (flame holding). That is, in the device described in patent document 1, backfire may occur.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a combustor and a gas turbine that promote mixing of fuel and air and further reduce the possibility of backfire.

Means for solving the problems

A burner according to an embodiment of the present invention includes: a plurality of fuel nozzles that extend in a nozzle axis direction and inject fuel toward one side in the nozzle axis direction; a tube plate extending in the nozzle axis direction and formed with a plurality of air holes into which a tip end portion of each of the fuel nozzles is inserted and having a larger inner diameter size than the tip end portion; and a step surface that extends in a radial direction with respect to the nozzle shaft from a tip outer peripheral surface that is an outer peripheral surface of the tip portion, at a position on the other side of the tip portion than a tip end surface facing one side in the nozzle shaft direction.

According to the above configuration, the tip end portion of the fuel nozzle is inserted into the air hole, and a stepped surface that expands in the radial direction from the outer peripheral surface of the tip end portion (tip outer peripheral surface) is formed at a position on the other side than the tip end surface of the tip end portion. Thus, the flow of air forms a circulating flow region and a turbulent flow region on the downstream side of the step surface. The turbulence reaches the front end of the fuel nozzle, so that mixing of the fuel and air can be promoted. In particular, since the stepped surface is formed at the tip end portion inserted into the air hole where the flow rate of air is high, strong air turbulence is generated downstream of the stepped surface. This can further promote mixing of the fuel and the air. Further, since the stepped surface is provided on the other side of the front end surface of the fuel nozzle, the circulating flow caused by the stepped surface does not reach the front end of the fuel nozzle. Therefore, the possibility that the mixed gas containing the fuel is captured by the circulation flow is reduced, and backfire can be suppressed.

In the above burner, a region of the tip outer peripheral surface on one side in the nozzle shaft direction with respect to the step surface may extend from a radially outer side toward an inner side with respect to the nozzle shaft as going from the other side toward the one side.

According to the above configuration, the region on the one side of the stepped surface in the distal end outer peripheral surface is tapered by extending from the radially outer side to the radially inner side from the other side to the one side. Thereby, a flow is formed along this region toward the center of the fuel nozzle (i.e., the nozzle axis). As a result, the size of the circulating flow formed along the outer peripheral surface of the tip end is reduced, and flame holding in the vicinity of the tip end surface can be suppressed. Further, since the turbulence component generated by the step surface is also directed toward the center of the fuel nozzle (i.e., the nozzle axis), the turbulence component is supplied to the interface between the fuel and the air. This can further promote mixing of the fuel and the air.

In the above burner, the dimension of the region of the tip outer peripheral surface on the nozzle axial direction side of the stepped surface in the nozzle axial direction may be x, and the dimension of the stepped surface in the radial direction may be s, so as to satisfy 5 < x/s < 20.

According to the above configuration, the circulating flow formed on the downstream side of the step surface can be reattached to the tip outer peripheral surface. In other words, according to the above configuration, the circulating flow can be stably formed on the downstream side of the step surface.

The burner has a plurality of turbulence projections formed with the step surface, the plurality of turbulence projections being arranged at intervals in a circumferential direction with respect to the nozzle shaft, and projecting radially from the leading end outer circumferential surface.

According to the above configuration, a plurality of turbulence protrusions protruding in the radial direction from the distal end outer circumferential surface are arranged at intervals in the circumferential direction. Thereby, a leakage flow of air is generated by the interval between the turbulence protrusions. As a result, the leakage flow interferes with the circulating flow formed on the downstream side of the step surface, and the size of the circulating flow can be reduced. Therefore, the possibility of backfiring caused by an excessively large circulating current can be further reduced.

In the above burner, 2 < x/s < 8 may be satisfied where x is a dimension of a region of the tip outer peripheral surface on a side of the step surface in the nozzle axial direction and s is a dimension of the step surface in the radial direction.

According to the above configuration, the circulating flow formed on the downstream side of the step surface can be reattached to the tip outer peripheral surface. In other words, according to the above configuration, the circulating flow can be stably formed on the downstream side of the step surface.

A gas turbine according to an embodiment of the present invention includes: a compressor that generates compressed air; a combustor according to any one of the above embodiments, which mixes fuel with the compressed air and burns the fuel to generate combustion gas; and a turbine driven by the combustion gas.

According to the above configuration, a gas turbine capable of more stable operation can be provided.

Effects of the invention

According to the present invention, it is possible to provide a combustor and a gas turbine that promote mixing of fuel and air and further reduce the possibility of backfiring.

Drawings

Fig. 1 is an overall view showing the structure of a burner of a first embodiment of the present invention.

Fig. 2 is an enlarged sectional view of a main portion of the burner of the first embodiment of the present invention.

Fig. 3 is an explanatory diagram for explaining the flow of fluid around the fuel nozzle in the first embodiment of the present invention.

Fig. 4 is a diagram showing a modification of the fuel nozzle according to the first embodiment of the present invention.

Fig. 5 is an enlarged sectional view of a main portion of a burner of a second embodiment of the present invention.

Fig. 6 is a view of the combustor of fig. 5 as viewed from the nozzle axis direction.

Fig. 7 is a schematic diagram showing the structure of a gas turbine according to each embodiment of the present invention.

Fig. 8 is an enlarged view of a main portion of a burner according to a modification of the present invention.

Detailed Description

[ first embodiment ]

A first embodiment of the present invention will be described with reference to fig. 1 to 4 and fig. 7. As shown in fig. 7, the combustor 100 of the present embodiment is a device used as, for example, one element of a gas turbine. The gas turbine 90 includes: a compressor 70 that generates compressed air, a combustor 100 that generates combustion gases, and a turbine 80 that is driven by the combustion gases. The combustor 100 mixes and burns fuel with air (compressed air) introduced from the outside to generate high-temperature and high-pressure combustion gas.

As shown in fig. 1, the combustor 100 includes: a cylinder 1, a closing plate 2, a tube plate 3, a fuel supply tube 4, a cavity 5, and a fuel nozzle 6. The cylinder 1 is cylindrical about a principal axis Am. A disk-shaped tube sheet 3 is mounted on one side of the cylinder 1 in the direction of the main axis Am. Specifically, the tube sheet 3 has: a tube plate body 3H in which a plurality of air holes 31 described later are formed, and a cylindrical fitting portion 3A extending in the direction of the main axis Am from an end edge on the outer peripheral side of the tube plate body 3H. The tube plate 3 is fixed to the cylindrical body 1 by fitting the fitting portion 3A to the inner peripheral surface of the cylindrical body 1. The end of the other side of the cylinder 1 in the direction of the main axis Am is closed by a closing plate 2.

The fuel supply pipe 4, the cavity 5, and the fuel nozzle 6 are housed inside the cylinder 1. The fuel feed pipe 4 penetrates the closing plate 2 in the direction of the main axis Am. Fuel is supplied from the outside through the fuel supply pipe 4. A cavity 5 is attached to one end of the fuel supply pipe 4. A plurality of fuel nozzles 6 are provided on one end surface of the cavity 5. Each fuel nozzle 6 extends along a nozzle axis An parallel to the main axis Am. Air holes 31 are formed in the tube plate 3 at positions corresponding to the fuel nozzles 6. The air holes 31 penetrate the tube plate 3 in the nozzle axis An direction. That is, the fuel nozzle 6 and the air hole 31 are disposed coaxially on the nozzle axis An. The inner diameter of each air hole 31 is larger than the outer diameter of the fuel nozzle 6.

Next, the structure of the fuel nozzle 6 will be described with reference to fig. 2. As shown in the figure, the fuel nozzle 6 includes: a body portion 6A located outside the air hole 31, and a tip portion 6B inserted into the air hole 31. The surface of the tip portion 6B facing the nozzle axis An direction side is a tip surface S1. An injection hole H for injecting fuel is formed in the tip end surface S1. The outer peripheral surface of the distal end portion 6B is a distal end outer peripheral surface S2. The most proximal region in the nozzle axis An direction of the distal end outer peripheral surface S2 is a tapered surface St. The tapered surface St extends from the radially outer side to the radially inner side as going from the other side to the one side in the nozzle axis An direction.

The other end edge of the tapered surface St is connected to the step surface S3. The step surface S3 is annular and radially expanded from the distal end outer peripheral surface S2 (tapered surface St). More specifically, in the present embodiment, the step surface S3 spreads in a plane orthogonal to the nozzle axis An. That is, the step surface S3 forms a step at the distal end portion 6B. The radially outer end edge of the step surface S3 is connected to the upstream outer circumferential surface Su. The upstream outer circumferential surface Su is continuous with the outer circumferential surface of the main body portion 6A, and has a constant diameter over the entire region in the extending direction thereof.

As shown in fig. 3, when the dimension of the region on the one side of the stepped surface S3 (i.e., the tapered surface St) in the tip outer peripheral surface S2 in the nozzle axis An direction is x and the dimension of the stepped surface S3 in the radial direction (i.e., the dimension of the stepped surface S3 in the radial direction with respect to the end edge of the tapered surface St on the radially innermost side) is S, the value of x/S is desirably satisfied by the following equation (1).

5＜x/s＜20···(1)

Further, it is more desirable that the value of x/s satisfies the following relation of expression (2).

8＜x/s＜16···(2)

Most desirably, the value of x/s satisfies the following relation of expression (3).

8＜x/s＜10···(3)

Next, the operation of the combustor 100 and the behavior of the fluid around the fuel nozzle 6 in the present embodiment will be described. When the combustor 100 is operated, as shown in fig. 1, first, fuel is supplied from the outside into the cavity 5 through the fuel supply pipe 4. At this time, high-pressure air is supplied to the inside of the cylindrical body 1. Fuel is supplied to the fuel nozzle 6 through the cavity 5. As described above, the tip portion 6B of the fuel nozzle 6 is inserted into the air hole 31, and a gap is formed between the outer peripheral surface of the tip portion 6B and the inner peripheral surface of the air hole 31. Therefore, as the fuel is injected from the injection hole H of the fuel nozzle 6, high-pressure air flows from the inside of the cylinder 1 into the air hole 31 through the gap. Therefore, the fuel and the air are mixed in the air hole 31 to generate a mixed gas. By igniting the mixture gas, a flame is formed on the downstream side (the nozzle axis An direction side) of each air hole 31.

Here, as shown in fig. 3, around the front end portion 6B of the fuel nozzle 6, after the air flow a passes through the step surface S3, a turbulent flow Vo and a circulating flow Vr are formed. Specifically, the air flow a flowing along the upstream outer circumferential surface Su separates from the leading end outer circumferential surface S2 when reaching the step surface S3, and forms a turbulent flow Vo containing a vortex flow on the downstream side of the step surface S3. On the other hand, in the region along the step surface S3 and the tapered surface St, the remaining components of the airflow a are retained, and the circulating flow Vr is formed.

The turbulent flow Vo reaches the front end (front end face S1) of the fuel nozzle 6, whereby the mixing of the fuel and the air can be promoted. In particular, since the stepped surface S3 is formed at the distal end portion 6B inserted into the air hole 31, air having a higher flow velocity passes around the stepped surface S3. This increases the intensity of the turbulent flow Vo, and can further promote the mixing of the fuel and the air. Further, since the step surface S3 is provided on the other side (upstream side) of the front end surface S1 of the fuel nozzle 6, the circulating flow Vr caused by the step surface S3 does not reach the front end (front end surface S1) of the fuel nozzle 6. Therefore, the possibility that the mixture gas containing the fuel is trapped by the circulation flow Vr is reduced, and backfire can be suppressed. As described above, according to the combustor 100 of the present embodiment, the possibility of backfiring can be further reduced while promoting the mixing of fuel and air.

Further, according to the above configuration, the region on the one side of the step surface S3 in the distal end outer peripheral surface S2 extends from the radially outer side to the radially inner side from the other side to the one side, thereby forming the tapered surface St. This forms a flow toward the center of the fuel nozzle 6 (i.e., the nozzle axis An) along the tapered surface St. As a result, the circulating flow Vr formed along the distal end outer peripheral surface S2 becomes small in size, and flame holding in the vicinity of the distal end surface S1 can be suppressed. Since the turbulent flow Vo generated by the step surface S3 is also directed toward the center of the fuel nozzle 6 (i.e., the nozzle axis An), a component including the turbulent flow Vo is supplied to the boundary P between the fuel and the air. This can further promote the mixing of the fuel and the air.

In the above burner, 5 < x/S < 20 is satisfied where x is the dimension in the nozzle axis An direction of the region on the nozzle axis An side of the stepped surface S3 in the tip outer peripheral surface S2, and S is the dimension of the stepped surface S3 in the radial direction. With this configuration, the circulating flow Vr formed on the downstream side of the step surface S3 can be caused to adhere to the leading end outer peripheral surface S2 again. In other words, according to the above configuration, the circulating flow Vr can be more stably formed on the downstream side of the step surface S3.

The first embodiment of the present invention has been described above. It is to be noted that various changes and modifications can be made to the above-described configuration without departing from the scope of the present invention. For example, as shown in fig. 4, An annular rib 8 centered on the nozzle axis An may be provided on the distal end outer peripheral surface S2, and a surface of the rib 8 facing one side in the direction of the nozzle axis An may be set as a stepped surface S3. That is, in this configuration, the upstream outer circumferential surface Su' on the other side from the rib 8 and the end edge on the other side of the tapered surface St are provided at the same position in the radial direction with respect to the nozzle axis An. With this configuration, the same operational effects as described above can be obtained.

[ second embodiment ]

Next, a second embodiment of the present invention will be described with reference to fig. 5 and 6. The same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in fig. 5 and 6, in the present embodiment, a plurality of (8, as an example) turbulence protrusions 9 protruding in the radial direction from the leading end outer peripheral surface S2 are arranged at intervals in the circumferential direction. The surface of each of the turbulence protrusions 9 facing the nozzle axis An direction is a step surface S3. The step surface S3 expands in the radial direction with respect to the nozzle axis An. In addition, each of the turbulence protrusions 9 has a rectangular cross-sectional shape in a cross-sectional view including the nozzle axis An.

The value of x/s described in the first embodiment satisfies the following relationship of expression (4) in the present embodiment.

2＜x/s＜8…(4)

More preferably, the value of x/s satisfies the following relation of expression (5).

3＜x/s＜7…(5)

Most desirably, the value of x/s satisfies the following relationship of expression (6).

4＜x/s＜6…(6)

According to the above configuration, the plurality of turbulence protrusions 9 protruding in the radial direction from the leading end outer peripheral surface S2 are arranged at intervals in the circumferential direction. Thereby, a leakage flow of air is generated by the interval between the turbulence protrusions 9. As a result, this leakage flow interferes with the circulating flow Vr formed on the downstream side of the step surface S3, and the magnitude of the circulating flow Vr can be reduced. Therefore, the possibility of backfiring caused by an excessively large circulating current Vr can be further reduced.

In the above configuration, when the dimension of the area on the nozzle axis An direction side of the stepped surface S3 in the distal end outer peripheral surface S2 is x in the nozzle axis An direction and the dimension of the stepped surface in the radial direction is S, 2 < x/S < 8 is satisfied. This allows the circulating flow Vr formed on the downstream side of the step surface S3 to adhere to the leading end outer peripheral surface S2 again. In other words, according to the above configuration, the circulating flow Vr can be more stably formed on the downstream side of the step surface S3.

The second embodiment of the present invention has been described above. It is to be noted that various changes and modifications can be made to the above-described configuration without departing from the scope of the present invention. For example, as a modification common to the above-described embodiments, a configuration as shown in fig. 8 may be adopted. In each of the above embodiments, the example in which the step surface S3 extends in a plane orthogonal to the nozzle axis An has been described, but in the example of fig. 8, the step surface S3' is a conical surface that forms An angle θ 2 smaller than 90 ° with respect to the nozzle axis An. The angle θ 2 is larger than θ 1, which is An angle formed by the tapered surface St with respect to the axis An. With this configuration, the same operational effects as those of the above-described embodiments can be obtained.

Industrial applicability

According to the present invention, it is possible to provide a combustor and a gas turbine that promote mixing of fuel and air and further reduce the possibility of backfiring.

Description of reference numerals:

a burner;

a cylinder;

a closure plate;

a tube sheet;

a fitting portion;

a tube sheet body;

an air hole;

a fuel feed pipe;

a cavity;

a fuel nozzle;

a main body portion;

a front end portion;

a rib;

disorganized bumps;

a compressor;

80.. a turbine;

90.. a gas turbine;

am... major axis;

an.. nozzle axis;

h. an injection hole;

a boundary surface;

s1. a front end face;

s2. the outer peripheral surface of the front end;

s3. step surface;

st.. taper;

outer peripheral surface of the upstream side;

vo... turbulence;

vr..