Patent Description:
A gas turbine is a power engine that mixes air compressed by a compressor with fuel for combustion and rotates a turbine with a high-temperature gas produced by the combustion. The gas turbine is used to drive a generator, an aircraft, a ship, a train, or the like.

The gas turbine includes a compressor, a combustor, and a turbine. The compressor sucks and compresses outside air, and transmits the compressed air to the combustor. The air compressed by the compressor is in a high-pressure and high-temperature state. The combustor mixes the compressed air compressed by the compressor with fuel and burns a mixture to produce combustion gas which is discharged to the turbine. Turbine blades in the turbine are rotated by the combustion gas to generate power. The generated power is used in various fields such as generating electric power and actuating machines.

Fuel is injected through nozzles installed in each combustor section of the combustor, and the nozzles enable injection of gas fuel and liquid fuel. Recently, it is recommended to use hydrogen fuel or fuel containing hydrogen to suppress carbon dioxide emission.

However, because hydrogen has a high combustion rate, when hydrogen fuel or fuel containing hydrogen is burned in a gas turbine combustor, the flame formed in the gas turbine combustor approaches the structure of the gas turbine combustor and is heated, which may cause a problem in the reliability of the gas turbine combustor.

In order to solve this problem, <CIT> discloses a combustor nozzle having a fuel supply duct. However, in the nozzle having the fuel supply duct, it may be difficult to uniformly mix fuel and air because a swirler is not installed in the nozzle.

<CIT> discloses a fuel injector for a gas turbine comprising a plenum defined by an upstream plate, a downstream plate, and a circumferential wall. A fuel supply pipe opens into the plenum so that gaseous fuel can be supplied to the plenum through the supply pipe. The injector further includes a plurality of premix tubes that extend through the plenum and are supported by the upstream and the downstream plate, respectively. Each premix tube has radial through holes to communicate an inner space of the respective premix tube with the plenum to receive fuel from the plenum. An inlet port of each premix tub includes a guide part that forms a swirler to swirl air introduced into the premix tube at the inlet port.

<CIT> discloses a structure in which different fuel gases are introduced into a mixing tube via through holes that are spaced from oneanother in an upstream-downstream-direction and that are inclined relative to an axis of the mixing tube. Air is introduced only at an inlet port into the mixing tube.

It is one of the ideas of the present invention to provide a combustor nozzle capable of minimizing backfire and improving fuel-air mixing characteristics to reduce NOX emission and increase flame stability by swirlers and fuel inlet holes formed in each injection tube, a combustor, and a gas turbine including the same.

Additional concepts of the invention will be set forth in part in the description which follows and, in part, will become apparent from the description, or may be learned by practice of the exemplary embodiments.

To this end, the present invention provides a nozzle in accordance with claim <NUM>.

According to a first aspect of the invention, there is provided a nozzle for a combustor configured to burn fuel containing hydrogen including: a fuel supply duct including a plurality of injection tubes through which air and fuel flow and a fuel passage through which fuel flows, a plurality of swirlers formed on a side surface of each of the plurality of injection tubes to guide air outside the injection tube to be introduced thereinto for swirling, and a plurality of fuel inlet holes formed radially through the injection tube to communicate with the fuel passage and allow fuel to flow through the fuel passage to the injection tube.

The plurality of swirlers are tube swirlers formed on the side surface of the injection tube to guide air to be introduced through the plurality of swirlers in a circumferential direction.

Each of the tube swirlers may include a swirl guide hole formed through the side surface of the injection tube at an angle of <NUM> to <NUM> degrees, and a swirl guide connected to the swirl guide hole so as to be coupled to one side of the swirl guide hole and gradually radially directed in the circumferential direction of the other side.

The tube swirler is disposed between one end of the injection tube for introducing air and the fuel inlet holes.

Alternatively, the fuel inlet holes are arranged between one end of the injection tube for introducing air and the tube swirlers.

The fuel supply duct may further include a plurality of diffusion nozzle tubes arranged between the injection tubes and having an end cap formed at each end, the end cap having a plurality of diffusion injection holes formed therein.

The plurality of diffusion injection holes of the diffusion nozzle tube may be formed through an edge of the end cap to be inclined outwardly.

The plurality of swirlers may be hole swirlers formed through the side surface of the injection tube to contact with an inner peripheral surface and configured to guide air introduced through the plurality of swirlers in a circumferential direction.

The fuel inlet holes may be formed radially through the side surface of the injection tube to communicate with the fuel passage and allow fuel to flow through the fuel passage to the injection tube. The fuel inlet holes may be arranged between one end of the injection tube for introducing air and the hole swirlers.

According to a second aspect of the invention, there is provided a combustor including: a nozzle assembly having a plurality of nozzles in accordance with the first aspect of the invention configured to inject fuel and air, and a duct assembly coupled to one side of the nozzle assembly to burn a mixture of the fuel and the air and transmit combustion gas to a turbine.

According to a third aspect of the invention, there is provided a gas turbine including: a compressor configured to compress air introduced from an outside, a combustor in accordance with the second aspect of the invention configured to mix fuel with the air compressed by the compressor and combust a mixture of the fuel and air to produce combustion gas, and a turbine having a plurality of turbine blades rotated by combustion gas produced in the combustor. The duct assembly of the combustor transmits the combustion gas to the turbine.

The above and other aspects will become more apparent from the following description of the exemplary embodiments with reference to the accompanying drawings, in which:.

Various modifications and different embodiments will be described below in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the invention. It should be understood, however, that the present invention is not intended to be limited to the specific embodiments, but the present invention includes all modifications, equivalents or replacements that fall within the scope of the invention as defined in the following claims.

The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of the invention. In the invention, terms such as "comprises", "includes", or "have/has" should be construed as designating that there are such features, integers, steps, operations, components, parts, and/or combinations thereof, not to exclude the presence or possibility of adding of one or more of other features, integers, steps, operations, components, parts, and/or combinations thereof.

Hereinafter, exemplary embodiments will be described below in detail with reference to the accompanying drawings. It should be noted that like reference numerals refer to like parts throughout the various figures and exemplary embodiments. In certain embodiments, a detailed description of functions and configurations well known in the art may be omitted to avoid obscuring appreciation of the invention by those skilled in the art. For the same reason, some components may be exaggerated, omitted, or schematically illustrated in the accompanying drawings.

<FIG> is a view illustrating an interior of a gas turbine according to an exemplary embodiment. <FIG> is a view illustrating a combustor of <FIG>.

The thermodynamic cycle of the gas turbine may ideally comply with the Brayton cycle. The Brayton cycle consists of four phases including isentropic compression (i.e., an adiabatic compression), isobaric heat addition, isentropic expansion (i.e., an adiabatic expansion), and isobaric heat dissipation. In other words, in the Brayton cycle, thermal energy may be released by combustion of fuel in an isobaric environment after the atmospheric air is sucked and compressed to a high pressure, high-temperature combustion gas may be expanded and converted into kinetic energy, and exhaust gas with residual energy may be discharged to the atmosphere. As such, the Brayton cycle consists of four processes including compression, heating, expansion, and exhaust.

The gas turbine <NUM> employing the Brayton cycle includes a compressor <NUM>, a combustor <NUM>, and a turbine <NUM>. Although the following description will be described with reference to <FIG>, the present invention may be widely applied to other turbine engines having similar configurations to the gas turbine <NUM> illustrated in <FIG>.

Referring to <FIG>, the compressor <NUM> of the gas turbine <NUM> is configured to suck air from the outside and compress the air to supply air for combustion to the combustor <NUM> and to supply the air for cooling to a high-temperature region of the gas turbine <NUM> that is required to be cooled. In this case, because the air sucked into the compressor <NUM> is subject to an adiabatic compression process therein, the pressure and temperature of the air passing through the compressor <NUM> increases.

The compressor <NUM> may be designed in a form of a centrifugal compressor or an axial compressor, and the centrifugal compressor is applied to a small gas turbine, whereas a multistage axial compressor is applied to a large gas turbine <NUM> illustrated in <FIG> to compress a large amount of air. In the multistage axial compressor, the compressor blades <NUM> rotate along with a rotation of rotor disks, compress the introduced air and deliver the compressed air to compressor vanes <NUM> disposed at a following stage. The air is compressed gradually to a high pressure while passing through the compressor blades <NUM> formed in a multistage manner.

A plurality of compressor vanes <NUM> may be mounted in a compressor casing <NUM> in such a way that the plurality of compressor vanes <NUM> form each stage. The plurality of compressor vanes <NUM> guide the compressed air flowing from compressor blades <NUM> disposed at a preceding stage to compressor blades <NUM> disposed at a following stage. For example, at least some of the plurality of compressor vanes <NUM> may be rotatably mounted within a predetermined range, e.g., to adjust an inflow rate of air.

The compressor <NUM> may be driven by a portion of the power output from the turbine <NUM>. To this end, a rotary shaft of the compressor <NUM> may be directly connected to a rotary shaft of the turbine <NUM>. In the case of the large-scale gas turbine <NUM>, almost half of the power generated by the turbine <NUM> may be consumed to drive the compressor <NUM>. Accordingly, an overall efficiency of the gas turbine <NUM> can be enhanced by directly increasing the efficiency of the compressor <NUM>.

The turbine <NUM> includes a plurality of rotor disks <NUM>, a plurality of turbine blades radially arranged on each of the rotor disks <NUM>, and a plurality of turbine vanes. Each of the rotor disks <NUM> has a substantially disk shape, and a plurality of grooves are formed in an outer periphery thereof. Each groove is formed to have a curved surface so that the turbine blades are inserted into the grooves, and the turbine vanes are mounted in a turbine casing. The turbine vanes are fixed so as not to rotate and guide the flow direction of the combustion gas passing through the turbine blades. The turbine blades generate rotational force while rotating by the combustion gas.

The combustor <NUM> is configured to mix the compressed air supplied from an outlet of the compressor <NUM> with fuel for isobaric combustion to produce combustion gas with high energy. <FIG> illustrates an example of the combustor <NUM> applied to the gas turbine <NUM>. The combustor <NUM> includes a nozzle assembly <NUM>, a nozzle <NUM>, and a duct assembly <NUM>, and may include a combustor casing <NUM>.

The combustor casing <NUM> may have a substantially cylindrical shape to surround a plurality of nozzle assemblies <NUM>. The nozzle assemblies <NUM> may be disposed along the annular combustor casing <NUM> downstream of the compressor <NUM>. Each of the nozzle assemblies <NUM> includes a plurality of nozzles <NUM>, and the fuel injected from the nozzles <NUM> is mixed with air at an appropriate rate so that the mixture thereof is suitable for combustion.

The gas turbine <NUM> may use gas fuel containing hydrogen. The fuel may be either hydrogen fuel alone or fuel containing hydrogen and natural gas.

Referring to <FIG>, compressed air is supplied to the nozzles <NUM> along an outer surface of the duct assembly <NUM>, which connects a section between the nozzle assemblies <NUM> and the turbine <NUM> so that high-temperature combustion gas flows to heat the duct assembly <NUM>, thereby properly cooling the heated duct assembly <NUM>.

The duct assembly <NUM> may include a liner <NUM>, a transition piece <NUM>, and a flow sleeve <NUM>. The duct assembly <NUM> has a double-wall structure in which the flow sleeve <NUM> surrounds the liner <NUM> and the transition piece <NUM>. The liner <NUM> and the transition piece <NUM> are cooled by the compressed air permeated into an annular space <NUM> formed inside the flow sleeve <NUM>.

The liner <NUM> is a tubular member connected to the nozzle assembly <NUM> of the combustor <NUM>, and a combustion chamber <NUM> is an internal space of the liner <NUM>. The liner <NUM> has one longitudinal end coupled to the nozzle assembly <NUM> and the other longitudinal end coupled to the transition piece <NUM>.

The transition piece <NUM> is connected to an inlet of the turbine <NUM> to guide high-temperature combustion gas to the turbine <NUM>. The transition piece <NUM> has one longitudinal end coupled to the liner <NUM> and the other longitudinal end coupled to the turbine <NUM>. The flow sleeve <NUM> serves to protect the liner <NUM> and the transition piece <NUM> to prevent high-temperature heat from being directly released to the outside.

<FIG> is a front view illustrating one nozzle assembly according to an exemplary embodiment. <FIG> is a longitudinal cross-sectional view of one nozzle according to an exemplary embodiment. <FIG> is a perspective view illustrating a portion of the nozzle according to an exemplary embodiment.

Referring to <FIG>, the nozzle <NUM> includes a fuel supply duct <NUM> which includes a plurality of injection tubes <NUM> through which air and fuel flow and a fuel passage <NUM> through which fuel flows and a plurality of fuel inlet holes <NUM> formed radially through each injection tube <NUM> to communicate with the fuel passage <NUM> so that fuel can be introduced into the injection tube <NUM>.

The nozzle <NUM> may further include a fuel supply pipe <NUM> for supplying fuel to the fuel supply duct <NUM>. Here, the fuel may be gas containing hydrogen. Although it is illustrated in the drawing that the fuel supply duct <NUM> is divided into six fuel supply ducts and the fuel supply pipe <NUM> is connected to one side of each of the divided fuel supply ducts <NUM>, a plurality of fuel supply ducts <NUM> may be connected to the fuel supply pipe <NUM>.

The fuel supply duct <NUM> may include the injection tubes <NUM> to form several small flames using hydrogen gas. The injection tubes <NUM> may be spaced apart from each other in the fuel supply duct <NUM> and formed parallel to each other.

A blocking plate <NUM> is installed at ends of the injection tubes <NUM> to form a fuel passage through which fuel flows. The blocking plate <NUM> may block the space between each injection tube <NUM> to prevent fuel leakage.

The first halves of the injection tubes <NUM> may be mounted to and supported by a bracket <NUM>. The bracket <NUM> may surround the first halves of the injection tubes <NUM>, and the injection tubes <NUM> and a plurality of diffusion nozzle tubes <NUM> may be mounted through the bracket <NUM>.

The fuel introduced into the fuel supply duct <NUM> through the fuel supply pipe <NUM> flows along the fuel passage <NUM>. The fuel passage <NUM> provided with the injection tubes <NUM> passing through the fuel passage <NUM> surrounds the injection tubes <NUM>.

The fuel inlet holes <NUM> for introducing fuel may be formed along a side surface of each of the injection tubes <NUM>. The fuel inlet holes <NUM> may be spaced apart from each other on the injection tube <NUM> in a circumferential direction. Alternatively, the fuel inlet holes <NUM> may be longitudinally spaced apart from each other on the injection tube <NUM>. The injection tube <NUM> may have an injection port <NUM> formed to inject a mixture of air and fuel.

The fuel supply duct <NUM> may be mounted to surround the plurality of fuel inlet holes <NUM> formed in the plurality of injection tubes <NUM>. In other words, the plurality of injection tubes <NUM> are mounted to pass through the fuel supply duct <NUM>, and the fuel supply duct <NUM> may have a thin thickness to surround the plurality of fuel inlet holes <NUM> in the longitudinal direction of the injection tubes <NUM>. The fuel supply duct <NUM> may be in the form of a single circular disk that surrounds all the injection tubes <NUM> and has the fuel passage <NUM> therein, or may be formed in a fan shape to mount a predetermined number of injection tubes <NUM>. For example, six fan-shaped fuel supply ducts <NUM> may be mounted in the form of a circular disk in overall contour.

Accordingly, the fuel introduced through the fuel supply pipe <NUM> flows into the injection tubes <NUM> through the fuel inlet holes <NUM> while flowing to the fuel passage <NUM> inside the fuel supply duct <NUM>, and is injected into the combustion chamber together with air. The air and fuel introduced into the injection tubes <NUM> may be mixed and injected through the injection ports <NUM> for combustion. Therefore, air and fuel can be mixed more uniformly to form a stable flame.

<FIG> is a perspective view illustrating one injection tube according to a first exemplary embodiment of the invention. <FIG> is a cross-sectional view taken along a plane passing through a tube swirler in <FIG>. <FIG> is a longitudinal cross-sectional view of the injection tube in <FIG>. <FIG> is a partial perspective view illustrating one diffusion nozzle tube.

Each of the injection tubes <NUM> includes a plurality of swirlers formed on the side surface thereof to guide air from outside the injection tube to be introduced thereinto for swirling.

Referring to <FIG>, the swirlers are tube swirlers <NUM> formed on a side surface of the injection tube <NUM> to guide air introduced through the swirlers in the circumferential direction. Although two tube swirlers <NUM> are illustrated to be formed in one injection tube <NUM>, two to four tube swirlers <NUM> may be formed.

Referring to <FIG>, each of the tube swirlers <NUM> may include a swirl guide hole <NUM> formed through the side surface of the injection tube <NUM> at an angle of <NUM> to <NUM> degrees, and a swirl guide <NUM> connected to the swirl guide hole <NUM> so as to be coupled to one side of the swirl guide hole <NUM> and gradually radially directed in the circumferential direction of the other side.

The swirl guide hole <NUM> may include two swirl guide holes formed through the side surface of the injection tube <NUM> at an angle close to <NUM> degrees, each having a rectangular shape. The swirl guide <NUM> may have a curved shape having a slightly larger radius of curvature than the side surface of the injection tube <NUM>. One end of the swirl guide <NUM> may be integrally connected to one end of the swirl guide hole <NUM>, and the other end may be formed to be spaced apart from the other end of the swirl guide hole <NUM> by a predetermined distance in a radial direction. The swirl guide <NUM> may have both side edges connected integrally to both ends of the swirl guide hole <NUM>. Thus, as illustrated in <FIG>, air outside the injection tube <NUM> may be introduced into the inlets of the pair of swirl guides <NUM> and then flow into the injection tube <NUM> through the swirl guide holes <NUM> while swirling.

For example, if four tube swirlers <NUM> are formed in one injection tube <NUM>, four swirl guide holes <NUM> and four swirl guides <NUM> may be formed at an angle of less than <NUM> degrees.

The fuel inlet holes <NUM> may be formed radially through the side surface of the injection tube <NUM> to communicate with the fuel passage, so that fuel is introduced into the injection tube <NUM> through the fuel inlet holes <NUM>. As illustrated in <FIG> and <FIG>, eight fuel inlet holes <NUM> may be formed through the side surface of the injection tube <NUM>, each having a circular shape. The fuel inlet holes <NUM> may be spaced apart from each other by a predetermined distance, and may be formed to face a center of the injection tube <NUM>.

In the injection tube <NUM>, the tube swirler <NUM> is disposed between one end of the injection tube <NUM> for introducing air and the fuel inlet holes <NUM>. Therefore, the primary air flowing into one end of the injection tube <NUM> and the secondary air flowing into and swirling through the tube swirlers <NUM> may be properly mixed in the injection tube <NUM> with the gas fuel introduced through the fuel inlet holes <NUM>.

Referring to <FIG>, <FIG>, and <FIG>, the fuel supply duct <NUM> may include a plurality of diffusion nozzle tubes <NUM> arranged between the injection tubes <NUM>. The diffusion nozzle tube <NUM> may have an end cap <NUM> formed at an end thereof, and the end cap <NUM> may have a plurality of diffusion injection holes <NUM> formed therein.

<FIG> illustrates an example in which a plurality (e.g., <NUM>) of injection tubes <NUM> and a plurality (e.g., <NUM>) of diffusion nozzle tubes <NUM> are arranged. As illustrated in <FIG>, the end cap <NUM> may be in the form of a circular disk having a predetermined thickness and may be connected integrally to the diffusion nozzle tube <NUM> to block one end thereof. The end cap <NUM> may have an edge chamfered to be inclined. The diffusion injection holes <NUM> may be formed perpendicular to the chamfered edge of the end cap <NUM>.

The diffusion nozzle tube <NUM> may have the diffusion injection holes <NUM> formed therethrough and inclined at a predetermined angle with respect to the center of the diffusion nozzle tube <NUM>. In other words, the diffusion injection holes <NUM> in the diffusion nozzle tube <NUM> may be formed through the edge of the end cap <NUM> to be inclined at a predetermined angle in a tangential direction tangential.

Accordingly, the diffusion nozzle tube <NUM> may include the diffusion injection holes <NUM> inclined with respect to the longitudinal direction to generate a swirl flow of air introduced into the diffusion nozzle tube <NUM> so that it can be well mixed with the air flowing into the injection tube <NUM> for combustion. For example, in a section of ignition and starting, the high air-to-fuel equivalence ratio increases the likelihood of backfire. However, the diffusion nozzle tubes <NUM> arranged between the injection tubes <NUM> can prevent backfire.

<FIG> is a perspective view illustrating one injection tube according to a second exemplary embodiment of the invention.

Referring to <FIG>, the injection tube <NUM> has a plurality of fuel inlet holes <NUM> arranged between one end of the injection tube <NUM> for introducing air and a plurality of tube swirlers <NUM>.

In the injection tube <NUM> of <FIG>, the fuel inlet holes <NUM> are arranged downstream of the tube swirlers <NUM> through which secondary air is introduced based on the flow direction of air. On the other hand, in the injection tube <NUM> of <FIG>, the tube swirlers <NUM> are disposed downstream of the fuel inlet holes <NUM>. Therefore, the primary air introduced into one end of the injection tube <NUM> may be first mixed with the gas fuel introduced through the fuel inlet holes <NUM>, and then remixed with the secondary air introduced through the tube swirlers <NUM>.

<FIG> is a perspective view illustrating one injection tube according to a third exemplary configuration not forming part of the present invention. <FIG> is a cross-sectional view taken along a plane passing through a hole swirler in <FIG>.

Referring to <FIG> and <FIG>, the injection tube <NUM> may include a hole swirler <NUM> formed through the side surface of the injection tube <NUM> to be in contact with the inner peripheral surface and configured to guide air introduced through the swirler in the circumferential direction.

Although the hole swirler <NUM> is illustrated to have two hole swirlers <NUM>, three or four hole swirlers may be formed. Each of the hole swirlers <NUM> may have a rectangular shape and may be elongated in the longitudinal direction when viewed from the outside of the injection tube <NUM>. The hole swirler <NUM> may be formed through the injection tube <NUM> to contact the inner peripheral surface so that the flow of air through the hole swirler <NUM> is swirled along the inner peripheral surface of the injection tube <NUM>. The secondary air introduced into the injection tube <NUM> through the hole swirlers <NUM> may be mixed with primary air and fuel while swirling in one direction in the injection tube <NUM>.

As illustrated in <FIG>, the injection tube <NUM> may have a plurality of fuel inlet holes <NUM> formed radially on the side surface of the injection tube <NUM> to communicate with the fuel passage and allow fuel to flow into the injection tube <NUM> therethrough. The fuel inlet holes <NUM> may be arranged between one end of the injection tube <NUM> for introducing air and the hole swirlers <NUM>.

The arrangement of the fuel inlet holes <NUM> and the hole swirlers <NUM> in the injection tube <NUM> of the third exemplary configuration is the same as in the injection tube <NUM> of the first exemplary embodiment, except for the shape of each hole swirler <NUM>.

As described above, according to the combustor nozzle, the combustor, and the gas turbine including the same, because the swirlers and the fuel inlet holes are formed in each injection tube, it is possible to minimize backfire and improve fuel-air mixing characteristics to reduce NOX emission and increase flame stability.

Claim 1:
A nozzle (<NUM>) for a gas turbine combustor configured to burn fuel containing hydrogen, comprising:
a fuel supply duct (<NUM>) comprising a plurality of injection tubes (<NUM>) through which air and fuel flow and a fuel passage (<NUM>) through which fuel flows;
a plurality of tube swirlers (<NUM>) formed on a side surface of each of the plurality of injection tubes (<NUM>) to guide air outside the injection tube (<NUM>) to be introduced into the injection tube (<NUM>) in a circumferential direction for swirling; and
a plurality of fuel inlet holes (<NUM>) formed radially through each injection tube (<NUM>) to communicate with the fuel passage (<NUM>) and allow fuel to flow through the fuel passage (<NUM>) to the injection tube (<NUM>),
characterized in that:
the respective tube swirler (<NUM>) is disposed between one end of the respective injection tube (<NUM>) for introducing air and the fuel inlet holes (<NUM>) of the respective injection tube (<NUM>), or
the fuel inlet holes (<NUM>) of the respective injection tube (<NUM>) are arranged between the end of the injection tube for introducing air and the respective tube swirler (<NUM>).