Patent Application
20190093562
The present disclosure relates to gas turbine engines. More particularly, the present disclosure relates to a scroll for a fuel injector assembly having a resonator to dampen vibrations in a gas turbine engine.
In combustion chambers of gas turbine engines, pressure or acoustic vibrations (or oscillations or pressure waves) may be generated during a combustion process. Commonly, such vibrations may range in frequencies from about twenty hertz to a few thousand hertz, and which may subject the combustion chamber to relatively severe mechanical loads. Such loads may interfere with an operation of the gas turbine engines and may decisively reduce a life of the combustion chamber, and of the components that are associated with the combustion chamber.
Acoustic vibrations (or oscillations) associated with the combustion process may cause vibrations in various parts or sub-systems of gas turbine engines. One such part and/or a sub-system may relate to an injector's fuel side or a fuel line of the gas turbines engines, and vibrations in such parts or sub-systems may cause an unsteady fuel supply to the combustion chamber, for example. To suppress or to attenuate vibrations in such parts or sub-systems, damping elements may need to be suitably positioned in the gas turbine engines. However, a complexity of gas turbine engine designs makes it difficult for such elements to be appropriately incorporated.
U.S. Pat. No. 9,383,097 relates to a staged fuel injector that includes, inter alia, a main fuel circuit for delivering fuel to a main fuel atomizer and a pilot fuel circuit for delivering fuel to a pilot fuel atomizer which is located radially inward of the main fuel atomizer. The main fuel atomizer includes a radially outer prefilmer and a radially inner fuel swirler. The prefilmer is formed using additive manufacturing.
In one aspect, the disclosure is directed towards a scroll for a fuel injector assembly of a gas turbine engine. The scroll includes a cylindrical body that has an axial end face and an inner surface defining a bore. A passage spans circumferentially within the cylindrical body around the bore. Further, an inlet channel extends from the axial end face to the passage and is configured to facilitate a flow of a fuel to the passage. Moreover, outlets are formed in the cylindrical body to facilitate a release of the fuel from the passage. The cylindrical body includes a resonator integrally formed with the cylindrical body. The resonator includes a chamber, and a channel that fluidly couples the chamber to the inlet port.
In another aspect, the disclosure relates to a fuel injector assembly for a gas turbine engine. The fuel injector assembly includes a fuel line and a scroll. The fuel line is configured to facilitate a supply of fuel to a combustor of the gas turbine engine. The scroll has a cylindrical body including an axial end face and an inner surface defining a bore. A passage spans circumferentially within the cylindrical body around the bore, with an inlet channel extending from the axial end face to the passage. The inlet channel is fluidly coupled to the fuel line to facilitate a flow of the fuel from the fuel line to the passage. Further, a plurality of outlets is formed in the cylindrical body to facilitate a release of the fuel from the passage for a delivery of the fuel into the combustor. The cylindrical body includes a resonator integrally formed with the cylindrical body. The resonator includes a chamber, and a channel fluidly coupling the chamber to the inlet port.
In yet another aspect, the disclosure is directed to a gas turbine engine. The gas turbine engine includes a combustor, a fuel line configured to facilitate a supply of fuel to the combustor, and a scroll. The scroll includes a cylindrical body including an axial end face and an inner surface defining a bore. A passage spans circumferentially within the cylindrical body around the bore. An inlet channel extends from the axial end face to the passage. Further, the inlet channel is fluidly coupled to the fuel line to facilitate a flow of the fuel from the fuel line to the passage. A plurality of outlets is formed in the cylindrical body to facilitate a release of the fuel from the passage for a delivery of the fuel into the combustor. The cylindrical body includes a resonator integrally formed with the cylindrical body. The resonator includes a chamber, and a channel fluidly coupling the chamber to the inlet port.
Referring to
The compressor section 110 includes a compressor disk assembly 120. The compressor disk assembly 120 includes multiple compressor rotor disks 122. Each compressor rotor disk 122 of the multiple compressor rotor disks 122 is circumferentially populated with a number of compressor blades 124 (only a single compressor blade 124 is annotated for clarity in
The combustor section 112 is configured to receive and mix the compressed air with the fuel to form an air-fuel mixture, and combust said air-fuel mixture for production of motive power. In further detail, the combustor section 112 includes a fuel injector assembly 136 and a combustor 138, with the fuel for mixing with the compressed air being provided by the fuel injector assembly 136.
The combustor 138 includes a combustor wall 140 that houses a combustion chamber 142 of the turbine engine 100. In one implementation, as shown in
The turbine section 114 is configured to receive the hot gases of combustion from the combustor section 112. As with the compressor section 110, the turbine section 114 includes a turbine disk assembly 160, and similar to the compressor disk assembly 120, the turbine disk assembly 160 includes multiple turbine rotor disks 162. Each turbine rotor disk 162 is circumferentially populated with a number of turbine blades 164 (only a single turbine blade 164 is annotated for clarity in
Referring to
The MG tube 170 facilitates a supply of a bulk of the fuel into the scroll 174, and thus into the combustor 138 (or combustion chamber 142) of the turbine engine 100. For example, the MG tube 170 may provide a fuel that is hydrocarbon with no air to the combustor 138 (or the combustion chamber 142) to inhibit or reduce the generation of oxides of nitrogen (NOx). The MG tube 170 may supply gaseous fuel from a gas manifold (not shown) to the scroll 174. For example, the MG tube 170 may include an end 178 (
The PG tube 172 may be coupled to and may be partially inserted into a pilot opening 180 of the scroll 174, and may be adapted to deliver a pressurized fuel into the combustion chamber 142 of the combustor 138. In one implementation, the PG tube 172 includes an end 182, and said end 182 may be welded or brazed to the scroll 174 at the pilot opening 180. Effectively, both the MG tube 170 and the PG tube 172 serve the purpose of supplying fuel into the combustion chamber 142 via two separate passages, satisfying one or more known functions associated with an operation of the combustor 138. Effectively, the MG tube 170 is a fuel line 184, or a main fuel line of the turbine engine 100, that facilitates a supply of the fuel to the combustor 138, while the PG tube 172 is a pilot fuel line 186 configured to inject a stream of pressurized fuel into the combustion chamber 142 of the combustor 138.
In some embodiments, the fuel injector 144 includes a flange 190 that supports an opposite end 192 (i.e. an end opposite to end 182) of the PG tube 172 and an opposite end 194 (i.e. an end opposite to end 178) of the MG tube 170. Said flange 190 may also support a variety of other tubes and structures (not discussed for clarity and conciseness) of the fuel injector 144. The flange 190 may facilitate a mounting of the fuel injector 144 to the turbine engine 100 (and, more specifically, to the combustor wall 140), and for this purpose, the flange 190 may include features such as one or more of fittings or connector assemblies (not shown). The flange 190 may be a cylindrical disk, although a variety of other shapes are possible, and may include handles 196 for handling the fuel injector 144.
The scroll 174 forms a portion of the fuel injector 144 that facilitates a mixing of the fuel with the compressed air received from the compressor section 110, and from which a mixture of the fuel and the compressed air (i.e. the air-fuel mixture) may be released and be delivered to the combustor 138. For mixing the air with fuel, in principle, the scroll 174 includes a swirler portion 200 that releases the fuel into a stream of the compressed air, during operation, such that an ensuing swirling action of the air-fuel mixture facilitates a distribution of the air-fuel mixture within the combustion chamber 142. Also, the scroll 174 includes a hollow cylindrical member 210. Aspects of the swirler portion 200 and the hollow cylindrical member 210 will be discussed later.
In further detail, the scroll 174 includes a cylindrical body 220 that defines a scroll axis 222. The cylindrical body 220 includes an axial end face 224 (i.e. at an axial end 226 of the cylindrical body 220). For the purpose of the ongoing discussion, the axial end face 224 may be referred to as a first end face 224, with the cylindrical body 220 including a second end face 228. The second end face 228 is axially and structurally opposed to the first end face 224 and includes a second end surface 230. The cylindrical body 220 further includes an outer surface 236 and an inner surface 238. The inner surface 238 defines a bore 240 of the scroll 174. It may be noted that an axis defined by the bore 240 may be same as the scroll axis 222. The bore 240 may be a through bore, extending from the first end face 224 all the way to the second end face 228. Further, the cylindrical body 220 includes a resonator 250, details of which will be discussed later in the application.
Referring to
Moreover, the cylindrical body 220 defines an inlet channel 258 extending from the first end face 224 to the passage 254, and which is configured to facilitate a flow of the fuel from the first end face 224 to the passage 254. The inlet channel 258 is fluidly coupled to the MG tube 170. In an embodiment, the passage 254 includes a start portion 260 (
Referring to
Further, each vane 262 includes one or more openings 266 (
The hollow cylindrical member 210 is supported by the end 276 (
The barrel 176 is coupled to the scroll 174 at the second end face 228 of the cylindrical body 220 of the scroll 174, and, for this purpose, the barrel 176 may engage or be press-fitted against a portion of the outer surface 236 of the cylindrical body 220. The barrel 176 houses a center body 280 with a center tube 282. The center tube 282 is positioned within the center body 280, with the center body 280 defining an annular space 286 with the center tube 282. The annular space 286 may be an extension of the pilot opening 180 within the center tube 282, along the scroll axis 222. The center tube 282 is configured to receive fuel from the PG tube 172, and is configured to inject said fuel into the combustor 138 (and thus into the combustion chamber 142) as a first stream. Further, the barrel 176 is positioned around the center body 280 to form an annular mixing duct 284 there between. The annular mixing duct 284 facilitates a mixing of fuel received through the openings 266 in the vanes 262 with the compressed air (flowing past the vanes 262 from the compressor section 110), to produce the air-fuel mixture (such as a lean premixed fuel). The annular mixing duct 284 is configured to deliver this lean premixed fuel into the combustor 138 (and thus into the combustion chamber 142) as a second stream, without mixing with the first stream. Notably, the pilot opening 180 provides a fuel-air mixture often richer than provided by the annular mixing duct 284 to facilitate flame stabilization within the combustor 138.
Referring to
The channel 302 is fluidly coupled between the chamber 300 and the inlet channel 258, thus fluidly coupling the chamber 300 to the inlet channel 258. In an embodiment, the channel 302 of the resonator 250 is defined along a plane 304 (plane 304 is marked as a surface defined by a cross-section of the cylindrical body 220 of the scroll 174). In an embodiment, the plane 304 is perpendicular to the scroll axis 222. Moreover, the channel 302 may include a cylindrical cross-sectional profile, although it is possible for the channel 302 to include a rectangular cross-sectional profile as well. In other examples, the channel 302 may possess an elliptical cross-sectional profile or an irregular cross-sectional profile. In an embodiment, the channel 302 is defined along a curvature of the cylindrical body 220, and thus, the channel 302 may be curved in profile as well, along an expanse of the plane 304 that is perpendicular to the scroll axis 222.
The chamber 300 may be configured to admit a volume of a fluid through the channel 302, and facilitate a dissipation of energy of a pressure wave generated from combustion (discussed in detail later). In one scenario, the chamber 300 includes a cylindrical shape (also see
Referring to
In an embodiment, the scroll 174 may be made of any material suitable for the application. For example, the scroll 174 may be made of a high strength, nickel based, corrosion resistant alloy, such as, for example, Hastelloy®. Further, the swirler portion 200 may be manufactured by the same materials, for example. In an embodiment, the scroll 174 and the swirler portion 200 are integrally formed as the cylindrical body 220. In an embodiment, the scroll 174 (i.e. the cylindrical body 220 of the scroll 174), or both the scroll 174 and the swirler portion 200, are formed by an additive manufacturing process. In an embodiment, additive manufacturing techniques include, for example, direct metal laser sintering (DMLS—a form of direct metal laser fusion (DMLF)) with nickel base super-alloys, low density titanium, and aluminum alloys. Other technique of additive manufacturing includes electron beam melting (EBM) with titanium, titanium aluminide, and nickel base super-alloy materials.
In one embodiment, the chamber 300 is a cylindrical chamber, and may include a volume of 0.306 cubic inch (in3). For example, a height of the chamber 300 may be 0.791 ins, while the diameter of the chamber 300 may be 0.701. Notably, the channel 302, in some implementations, may include a diameter of 0.070 inch (in), while a length of the channel 302 may be 0.809 in.
Referring to
Referring to
In one embodiment, the egress passages 320c, 320c′, 330d, 330d′, 320e, and 320e′, discussed above may be plugged using a plug (not shown) once an associated additive manufacturing/3-dimensional (3D) printing process is complete. For example, a plug, applied to any of the egress passages 320c, 320c′, 330d, 330d′, 320e, and 320e′, may be shape compliant with said corresponding egress passages 320c, 320c′. 330d, 330d′. 320e, and 320e′. Methods, such as brazing, may be applied to positively couple such a plug within corresponding egress passages 320c, 320c′, 330d, 330d′, 320e, and 320e′. Further, each plug may be sized to fill the corresponding egress passages 320c, 320c′, 330d, 330d′, 320e, and 320e′ fully, so as to leave the respective chambers 300c, 300d, 300d′, 300e, and 300e′, the intended size.
During operation of the turbine engine 100, air may be drawn into the turbine engine 100 and be compressed via the compressor section 110. Compressed air generated by the compressor section 110 may then be directed into the combustor section 112 through the fuel injector 144. It may be noted, that the fuel in PG tube 172 is typical gaseous hydrocarbons with no air. Within a passage between the center body 280 and the center tube 282, compressed air enters through the pilot opening 180. Some portion of that air enters the passage within center tube 282 along the scroll axis 222 via holes (not shown in
In further detail, as the compressed air flows through the swirler portion 200 and the barrel 176, towards the combustion chamber 142, a typical profile of the plurality of vanes 262 facilitates the generation of the swirling action of the air passing across each vane 262. This swirling action ensures a proper mix of the fuel, injected by each vane 262, with the compressed air received from the compressor section 110. Notably, this mixing forms the air-fuel mixture. The fuel/air mixture may then proceed to the combustion chamber 142. Notably, the swirling action may also help in a distribution of the air-fuel mixture in the combustion chamber 142, assisting in combustion.
As the air-fuel mixture enters the combustor 138 (i.e. the combustion chamber 142), the air-fuel mixture may be ignited and combusted. A release of energy accompanying the combustion process may heat the combustion chamber 142 and the gases within the combustion chamber 142. As a result, hot gases within the combustion chamber 142 may be formed, and which may start to expand within the combustion chamber 142. The hot expanding gases may then flow into turbine section 114, where the energy of the combustion gases may be converted to rotational energy of the turbine disk assembly 160 (i.e. the turbine rotor disks 162) and the shaft 108. Since the shaft 108 is also coupled to the compressor disk assembly 120, a rotation of the shaft 108 causes a rotation of the compressor disk assembly 120, in turn powering the compressor section 110 of the turbine engine 100. Thereafter, the hot expanding gases pass through the turbine disk assembly 160 and are expelled out of the turbine engine 100 as exhaust.
The combustion process may also give rise to instabilities that cause pressure waves within combustion chamber 142. These pressure waves may include regions of compressions (regions of high air pressure) and rarefactions (regions of low air pressure). The pressure waves may propagate in all directions within combustion chamber 142, out of the combustion chamber 142, and components associated with the combustion chamber 142 (or the combustor 138). Pressure waves may also impinge on the resonator 250, 250a. 250b formed within the fuel injector 144. For ease in understanding, further discussion will include references to only the resonator 250. Such discussions will be applicable for the resonators 250a, 250b, as well.
If pressure waves are left unchecked, vibrations may be generated that may continue until a source of energy causing the vibrations is removed, or until an operation of the turbine engine 100 is altered to a different operational range, for example. However, changing system variables and causing a change in operational characteristics of the turbine engine 100 may be undesirable in most situations. One or more aspects of the present disclosure are related to suppressing or attenuating vibrations in one or more parts or sub-systems of the turbine engine 100. Such parts or sub-systems relate to the injector's (i.e. the fuel injector 144's) fuel side or fuel lines (MG tube 170 and PG tube 172) of the turbine engine 100.
When pressure waves are generated, pressure waves impinge on the inlet channel 258 and thus the resonator 250. As a result, a small quantity of a fluid (which in this case is fuel) may be forced into chamber 300 since the chamber 300 is in fluid communication with the inlet channel 258 through the channel 302, thereby increasing a pressure inside the chamber 300. When a rarefied region (regions of low air pressure) of the pressure waves impinges on the inlet channel 258, a driving force that pushed the fluid (i.e. fuel) into the chamber 300 may reduce, and a pressurized fluid from inside the chamber 300 may flow back into the inlet channel 258 through the channel 302. Due to a momentum of the fluid flowing out of the chamber 300 (and thus the channel 302), this fluid outflow may continue past a point of pressure equilibrium and cause a lower pressure within chamber 300. This pressure imbalance may draw air back into the chamber 300, and the process may be repeated. Frictional and other losses during such repeated inflow and outflow of fluid (i.e. fuel) relative to the channel 302 and the chamber 300 may gradually dissipate the energy of the pressure waves, thereby damping the pressure waves.
Embodiments of the resonators 250c, 250d, 250d′, 250e, and 250e′, as described in
Referring to
In one scenario, fuels, such as gaseous fuels, incoming from the MG tube 170, may produce a residue of hydrocarbon condensates. In such a case, the auxiliary channel 302f may allow fuel to be vented out into the fuel injector 144, allowing fuel to spill back into a path of fuel flow (i.e. into the annular mixing duct 284), rather than venting out into the combustor 138, or dwelling within the chamber 300f and possibly undergoing undesirable chemical reactions.
The disclosed fuel injector 144 with the resonator 250 (which is a Helmholtz resonator) may be applicable to any turbine engine where reduced vibrations within the turbine engine are desired. Although particularly useful for low NOx-emitting engines, the disclosed fuel injector 144 may be applicable to any turbine engine regardless of the emission output of the turbine engine. The disclosed fuel injector 144 with the resonator 250 may reduce vibrations by acoustically attenuating naturally-occurring pressure fluctuations within the inlet channel 258 of the fuel injector 144, thus being able to effectively suppress or to attenuate vibrations in such parts or sub-systems of the turbine engine 100.
Further, by use of an additive manufacturing process, manufacturing complex geometries and surfaces of the resonator (i.e. of both the channel 302 and the chamber 300), is possible. Moreover, by additive manufacturing techniques, it is also possible to more easily integrate a structure of the resonators 250 into the cylindrical body 220 of the scroll 174 as compared to conventional manufacturing practice. Furthermore, having identified a suitable location of the resonator 250, such as within the scroll 174, and with the channel 302 fluidly extending into the inlet channel 258, additive manufacturing imparts more freedom to locate resonator chambers and resonator channels during a manufacturing, such as has been in this case (i.e. in the present disclosure). A suitable positioning of the resonator 250 results in a more effectively dampening of vibrations and oscillations.
Further, by use of an additive manufacturing process, it becomes easier for the scroll 174 and the swirler portion 200 to be integrally formed, as well. An integral scroll 174 and swirler portion 200 reduces assembly/disassembly time, and avoids effort typically required for mounting several components in an assembly, such as in an assembly of conventional scroll assemblies. For example, such as an end cap that may be generally assembled to a scroll from an end face (such as second end face 228) of the scroll 174. Moreover, integral structures attained through additive manufacturing techniques also reduce a bulk and complexity associated with the related assembly.
It will be apparent to those skilled in the art that various modifications and variations can be made to the system of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.
