Patent Application
20250180211
Exemplary embodiments relate to a combustor nozzle for operation in association with a combustor and gas turbine engine including the same. The combustor may use at least one of hydrogen fuel and natural gas fuel.
A gas turbine engine is a power engine that mixes air compressed by a compressor with fuel for combustion and rotates a turbine with hot gas produced by the combustion. The gas turbine engine is used to drive a generator, an aircraft, a ship, a train, etc.
The gas turbine engine typically includes a compressor, a combustor, and a turbine. The compressor sucks and compresses outside air, and then transmits the compressed air to the combustor. The combustor mixes the compressed air flowing thereinto from the compressor with fuel and burns a mixture thereof to generate high pressure and high temperature combustion gas. The combustion gas produced by the combustion is discharged to the turbine. Turbine blades in the turbine are rotated by the combustion gas, thereby generating 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 allow for injection of gas fuel and/or liquid fuel. In recent years, it is recommended to use hydrogen fuel or fuel containing hydrogen to inhibit or reduce the emission of carbon dioxide given that hydrogen is a carbon-free fuel.
However, while use of hydrogen fuel or fuel containing hydrogen enables the desired effect of inhibiting or reducing emission of carbon dioxide, problems can occur owing to the high combustion rate of hydrogen. That is, when hydrogen is introduced as a fuel, if the hydrogen is not thoroughly mixed with the compressed air generated by the compressor, the hydrogen can ignite prematurely or separately from the compressed air causing flashback in the nozzles or fuel/air mixing tubes. Such flashbacks can damage components of the gas turbine engine, and such flashbacks can lead to inefficient gas turbine engine operation owing to inconsistent energy to the gas turbine engine system. In addition, as proper pressure in the gas turbine engine system is necessary for efficient operation, premature or inefficient combustion of hydrogen fuel not properly mixed with compressed air can result in undesired pressure drops in the gas turbine engine system. Another problem owing to inefficient hydrogen fuel combustion is the production of nitrogen oxides (NOx). When air is heated to high temperatures, nitrogen which naturally occurs in air, combines with oxygen to produce NOx. Combusting hydrogen fuels mixed with compressed air when the hydrogen fuel is not properly mixed with the compressed air prior to combustion can result in over heating the compressed air which, in turn, can result in production of undesired levels of NOx.
There is a need in the art for a gas turbine engine fuel nozzle or fuel/air mixing tube in which fuels are mixed with compressed air in a manner that allows for efficient combustion of the fuels for improved gas turbine engine operation and that inhibits production of undesired byproducts.
Aspects of one or more exemplary embodiments provide a combustor nozzle that enables uniform mixing of fuel and air, a combustor, and a gas turbine engine including the same.
Additional aspects 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.
According to an aspect of an exemplary embodiment, there is provided a nozzle or fuel/air mixing tube for a combustor that improves the mixing of fuels with compressed air and that enables improved combustion of fuel/air mixtures. According to one aspect of the exemplary embodiment, the nozzle is comprised of a cylindrical tube through which air and fuel flow. The cylindrical tube has an inlet formed at a longitudinal end thereof for introduction of a first fluid (e.g., compressed air) into the cylindrical tube. The cylindrical tube has one or more supply ports formed on a circumferential surface of the cylindrical tube for introduction of a second fluid (e.g., fuel such as hydrogen or fuels containing hydrogen) into the cylindrical tube. According to an aspect, the cylindrical tube has at least one fuel/air separator disposed interior of the longitudinal end, the fuel/air separator operative to cause a flow of the second fluid to be enveloped by a flow of first fluid before the first and second fluids subsequently mix inside the cylindrical tube.
According to one aspect of an exemplary embodiment, the fuel/air separator is further operative to cause a first layer of the first fluid to flow along an inner surface of the cylindrical tube, to cause a layer of the second fluid to flow along an inner surface of the first layer of the first fluid, and to cause a second layer of the first fluid to flow along an inner surface of the layer of the second fluid. The second fluid flows between the first and second layers of the first fluid after the first and second fluids pass through the fuel/air separator.
According to another aspect of an exemplary embodiment, the fuel/air separator may comprise an outer ring-shaped member where an outer surface of the outer ring-shaped member is situated spaced-apart from an inner surface of the cylindrical tube for allowing passage of the first fluid between the outer surface of the outer ring-shaped member and the inner surface of the cylindrical tube such that a layer of the first fluid forms along an inner circumferential surface of the cylindrical tube. The fuel/air separator may also include an inner ring-shaped member where the outer surface of the inner ring-shaped member is situated spaced-apart from an inner surface of the outer ring-shaped member for allowing passage of the second fluid between the outer surface of the inner ring-shaped member and the inner surface of the outer ring-shaped member such that a layer of the second fluid forms along an inner circumferential surface of the layer of the first fluid. According to an aspect, the inner ring-shaped member has an orifice for allowing the first fluid to pass through the orifice into the cylindrical tube such that a generally tube-shaped layer of the first fluid passes inside the layer of the second fluid. Thus, according to this aspect, the second fluid is sandwiched between the layer of the first fluid and the generally tube-shaped layer of the first fluid such that the second fluid is insulated from the inner circumferential surface of the cylindrical tube. Interaction of the layer of the first fluid, the layer of the second fluid and the generally tube-shaped layer of the first fluid downrange in the cylindrical tube away from the inlet formed at the longitudinal end of the cylindrical tube causes the first and second fluids to mix into a third fluid comprised of the first and second fluids.
According to another aspect of an exemplary embodiment, each of the one or more supply ports comprises a tube for communicating the second fluid into the fuel/air separator from outside the cylindrical tube. The tube is configured for communicating the second fluid into the space between the inner surface of the outer ring-shaped member and the outer surface of the inner ring-shaped member. The tube may be configured to enter the space between the inner surface of the outer ring-shaped member and the outer surface of the inner ring-shaped member at an angle for optimizing flow of the second fluid into the fuel/air separator.
According another aspect of an exemplary embodiment, the cylindrical tube may be combined with one or more other cylindrical tubes to form a multi-tube configuration for passing a mixture of the first and second fluids through each of the combined cylindrical tubes for combustion in a combustor burner. According to this aspect, each of the one or more additional cylindrical tubes may have an inlet formed at a longitudinal end thereof for introduction of the first fluid into each of the one or more other cylindrical tubes. Each of the one or more additional cylindrical tubes may have one or more supply ports formed on a circumferential surface of each of the one or more other cylindrical tubes for introduction of the second fluid into each of the one or more other cylindrical tubes, and each of the one or more other cylindrical tubes may have at least one fuel/air separator disposed interior of the longitudinal end, the fuel/air separator operative to cause a flow of the second fluid to be enveloped by a flow of first fluid before the first and second fluids subsequently mix inside the cylindrical tube.
According to an aspect of another exemplary embodiment, there is provided a combustor including a burner having a plurality of nozzles for injecting fuel and air, and a duct assembly coupled to one side of the burner to burn a mixture of the fuel and the air therein and transmit combustion gas to a turbine. Each of the nozzles may comprise a cylindrical tube through which air and fuel flow. The cylindrical tube may have an inlet formed at a longitudinal end thereof for introduction of a first fluid into the cylindrical tube, and the cylindrical tube may have one or more supply ports formed on a circumferential surface of the cylindrical tube for introduction of a second fluid into the cylindrical tube. According to an aspect, the cylindrical tube may have at least one fuel/air separator disposed interior of the longitudinal end, the fuel/air separator operative to cause a flow of the second fluid to be enveloped by a flow of first fluid before the first and second fluids subsequently mix inside the cylindrical tube.
According to a further exemplary embodiment, a gas turbine engine is provided including a compressor configured to compress air introduced thereinto from the outside, a combustor configured to mix fuel with the air compressed by the compressor for combustion, and a turbine having a plurality of turbine blades rotated by combustion gas produced by the combustion in the combustor. The combustor may include a burner having a plurality of nozzles for injecting the fuel and the air, and a duct assembly coupled to one side of the burner to burn a mixture of the fuel and the air therein and transmit the combustion gas to the turbine. According to an aspect, each of the nozzles may comprise a cylindrical tube through which air and fuel flow. The cylindrical tube may have an inlet formed at a longitudinal end thereof for introduction of a first fluid into the cylindrical tube, and the cylindrical tube may have one or more supply ports formed on a circumferential surface of the cylindrical tube for introduction of a second fluid into the cylindrical tube. According to an aspect, the cylindrical tube may have at least one fuel/air separator disposed interior of the longitudinal end, the fuel/air separator operative to cause a flow of the second fluid to be enveloped by a flow of first fluid before the first and second fluids subsequently mix inside the cylindrical tube. According still to this aspect, a plurality of such configured nozzles may be combined to form a multi-tube nozzle configuration for efficient mixing of fuel and compressed air for combustion in a combustion chamber of the combustor of the gas turbine engine.
It is to be understood that both the foregoing general description and the following detailed description of exemplary embodiments are exemplary and explanatory and are intended to provide further explanation of the disclosure as claimed.
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 carry out the disclosure. It should be understood, however, that the present disclosure is not intended to be limited to the specific embodiments, but the present disclosure includes modifications, equivalents or replacements that fall within the spirit and scope of the disclosure 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 disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. In the disclosure, 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.
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 various drawings 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 disclosure by those skilled in the art. For the same reason, some components may be exaggerated, omitted, or schematically illustrated in the accompanying drawings.
Hereinafter, a gas turbine engine according to an exemplary embodiment will be described.
The gas turbine engine 100 using the above Brayton cycle may include a compressor 110, a combustor 120, and a turbine 130, as illustrated in
Referring still to
The compressor 110 may be designed as a centrifugal compressor or an axial compressor. In general, the centrifugal compressor is applied to a small gas turbine engine, whereas the multistage axial compressor is applied to the large gas turbine engine 100 as illustrated in
A plurality of compressor vanes 113, 114 may be formed in a multistage manner and mounted in a compressor casing 115. The compressor vanes 114 guide the compressed air, which flows from front-stage compressor blades 113, to rear-stage compressor blades 114. In an exemplary embodiment, at least some of the plurality of compressor vanes 114 may be mounted so as to be rotatable within a fixed range for regulating the inflow rate of air or the like.
The compressor 110 may be driven by some of the power output from the turbine 130. To this end, the rotary shaft of the compressor 110 may be directly connected to the rotary shaft of the turbine 130, as illustrated in
The turbine 130 includes a plurality of rotor disks 131, a plurality of turbine blades radially arranged on each of the rotor disks 131, and a plurality of turbine vanes (not shown). Each of the rotor disks 131 has a substantially disk shape and has a plurality of grooves formed on the outer peripheral portion thereof. The grooves are each 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 serve to guide the direction of flow of the combustion gas that has passed through the turbine blades. The turbine blades generate rotational force while rotating by the combustion gas.
Meanwhile, the combustor 120 may mix the compressed air, which is supplied from the outlet of the compressor 110, with fuel for isobaric combustion to produce combustion gas with high energy. That is, the combustor 120 mixes the compressed air, which is supplied from the outlet of the compressor 110, with fuel for isobaric combustion to produce combustion gas with high energy. The combustor 120 is disposed downstream of the compressor 110 and includes a plurality of burners 200 arranged annularly around a central axis of the gas turbine engine 100.
Referring now to
The gas turbine engine may use gas fuel containing hydrogen and/or natural gas, liquid fuel, or composite fuel as a combination thereof, which is the fuel fluid in the present exemplary embodiment. For the gas turbine engine, it is important to make a combustion environment for reducing an amount of emission such as carbon monoxide or nitrogen oxide that is subject to legal regulations. Accordingly, premixed combustion has been increasingly used in recent years in that it enables uniform combustion to reduce emission by lowering a combustion temperature even though it is relatively difficult to control the premixed combustion.
In the case of premixed combustion, after the compressed air introduced from the compressor 110 is mixed with fuel in the nozzle 300, the mixture thereof enters the combustion chamber 240. When combustion is stable after premixed gas is initially ignited by an igniter, the combustion is maintained by the supply of fuel and air.
The duct assembly 220 includes the combustion chamber 240, which is a space for combustion, and further includes a liner 250 and a transition piece 260.
The liner 250 may be disposed downstream of the nozzle 300 and may have a double structure of an inner liner 251 and an outer liner 252. That is, the liner 250 may have a double structure in which the inner liner 251 is surrounded by the outer liner 252. In this case, the inner liner 251 may be a hollow tubular member, and the inside of the inner liner 251 defines the combustion chamber 240. The inner liner 251 may be cooled by the compressed air penetrating into an annular space inside the outer liner 252 through a compressed air inlet hole H.
The transition piece 260 may be positioned downstream of the liner 250, which allows combustion gas produced in the combustion chamber 240 to be released at high speed to the turbine. The transition piece 260 may have a double structure of an inner transition piece 261 and an outer transition piece 262. That is, the transition piece 260 may have a double structure in which the inner transition piece 261 is surrounded by the outer transition piece 262. Like the inner liner 251, the inner transition piece 261 may also be a hollow tubular member. The inner transition piece 261 may have a diameter that gradually decreases from the liner 250 toward the turbine 130. In this case, the inner liner 251 and the inner transition piece 261 may be coupled to each other by a plate spring seal (not shown). The respective ends of the inner liner 251 and the inner transition piece 261 are fixed to the combustor 120 and the turbine, and the plate spring seal has a structure that accommodates an extension in length and diameter due to thermal expansion. As a result, the inner liner 251 and the inner transition piece 261 may be supported.
The outer liner 252 and the outer transition piece 262 may surround the inner liner 251 and the inner transition piece 261, respectively. Compressed air may penetrate into an annular space between the inner liner 251 and the outer liner 252 and an annular space between the inner transition piece 261 and the outer transition piece 262 through the compressed air inlet hole H (the illustrated aspect includes a plurality of holes H). The inner liner 251 and the inner transition piece 261 may be cooled by the compressed air penetrating into the annular spaces.
Meanwhile, the high-temperature and high-pressure combustion gas produced in the combustor 200 is supplied to the turbine 130 through the liner 250 and the transition piece 260. In the turbine 130, the combustion gas applies impingement or reaction force to the turbine blades radially disposed on the rotary shaft of the turbine 130 while expanding adiabatically, so that the thermal energy of the combustion gas is converted into mechanical energy for rotating the rotary shaft. Some of the mechanical energy obtained from the turbine 130 is supplied as energy required to compress air in the compressor, and the rest is utilized as effective energy, such as for driving the power generator to generate electric power.
Referring back to
Turning to
Referring to
The nozzle 300 may also include one or more outer nozzles 318 arranged radially around the central nozzle 310. For example, the illustrated nozzle 300 includes five outer nozzles 318 that may be independently operated based upon a desired power output from the gas turbine engine 100 (e.g., operating two of the outer nozzles 318 may produce 40% load output). Each of the outer nozzles 318 may include a housing 320 that is coupled to one or more of an adjacent housing or the central nozzle 310. Each of the outer nozzles 318 may also include a fuel supply tube 322. The fuel supply tube 322 may extend upstream from the housing 320 to the end cover 231 to receive fuel from a fuel source. Contained within the housing 320 is a plurality of mixing tubes 324. Each of the mixing tubes 324 includes a first opening 326 (see
According to an aspect of this embodiment, the cylindrical mixing tube 324 includes a fuel/air separator 329 disposed interior of the longitudinal end that is operative to cause a flow of the second fluid (e.g., fuel) to be enveloped by a flow of the first fluid (e.g., compressed air) before the first and second fluids subsequently mix inside the cylindrical mixing tube 324. As will be described in detail below with reference to
As described in detail below, the fuel/air separator 329 is operative to cause a first layer of the first fluid (e.g., compressed air) to flow through inlet openings 331 around an outer surface of the outer ring-shaped member 338 of the fuel air separator 329 and into the mixing tube 324 to generate a first layer of the first fluid along an inner surface of the mixing tube 324. A second fluid (e.g., fuel) is introduced into the fuel/air separator 329 through the supply ports 330. The second fluid exits through the back side of the fuel/air separator into the mixing tube 324 and flows into the mixing tube 324 interior of the first layer of the compressed air first fluid flowing along the inner surface of the tube 324. Simultaneously, the first fluid (e.g., compressed air) also enters the inlet 326 of the mixing tube 324 and passes through the orifice 332 of the inner ring-shaped member 340 in the fuel/air separator 329. As the compressed air first fluid passes through the orifice 332, it forms a generally tube-shaped flow of the first fluid so that the fuel flow passing from the fuel/air separator 329 is sandwiched between the flows of the first fluid or compressed air entering through the inlet openings 331 and the orifice 332, respectively. As illustrated in
As illustrated and described in detail below with reference to
Referring now to
Referring still to
Referring still to
In operation, the first fluid (compressed air flow 335A) passes between the outer surface of the outer ring-shaped member 338 and the inner surface of the mixing tube 324, the second fluid (fuel flow 336) passes into the space between the inner and outer members 338, 340 and then into the mixing tube 324, and the first fluid (compressed air flow 335B) passes through the orifice 332 and into the mixing tube 324 to form a generally tube-shaped flow. Thus, the layer of the first fluid (compressed air flow 335A), the layer of the second fluid (fuel flow 336) and the generally tube-shaped layer of the first fluid (compressed air flow 335B) form a fluid flow in the cylindrical mixing tube 324 past the fuel/air separator 329 whereby the layer of the second fluid is sandwiched between the layer of the first fluid and the generally tube-shaped layer of the first fluid such that the second fluid is insulated from the inner circumferential surface of the cylindrical mixing tube 324. Interaction of the layer of the first fluid, the layer of the second fluid and the generally tube-shaped layer of the first fluid downrange in the cylindrical tube away from the inlet formed at the longitudinal end of the cylindrical tube causes the first and second fluids to mix into a third fluid comprised of the first and second fluids (i.e., fuel/air mixture).
Thus, the resulting fluid flow into the mixing tube 324 initially beyond the fuel/air separator 329 includes a ring-shaped air flow 335A traveling along an inner surface of the mixing tube 324, a ring-shaped fuel flow 336B traveling along an inner surface of the layer of air flow 335A, and a generally tube-shaped air flow 335B traveling through the ring-shaped fuel flow 336B. That is, the ring-shaped fuel flow 336B is sandwiched between the ring-shaped air flow 335A and the generally tube-shaped air flow 335B. As described herein, insulating the fuel flow from the inner surface of the mixing tube 324 inhibits premature combustion or flashback of the fuel from contact with the heated inner surface of the mixing tube 324 and thus allows the fuel and compressed air to be thoroughly mixed inside the mixing tube for use as a fuel/air mixture in the gas turbine combustor.
While one or more exemplary embodiments have been described with reference to the accompanying drawings, it will be apparent to those skilled in the art that variations and modifications may be made by adding, changing, or removing components without departing from the spirit and scope of the disclosure as defined in the appended claims, and these variations and modifications fall within the spirit and scope of the disclosure as defined in the appended claims.
