System and method for providing output products to a combustion chamber of a gas turbine engine

Abstract

A system and method includes a plurality of fuel cell stacks extending around a combustion chamber. The plurality of fuel cell stacks are distributed along the axial length of the combustion chamber. The fuel cell stacks are configured to provide output products to the combustion chamber to achieve at least one of late lean injection and a desired combustor gas concentration profile.

Description

Technical Field

[0001] The present disclosure relates to systems and methods for providing output products to a combustion chamber of a gas turbine engine, the propulsion system including a fuel cell. Background Art

[0002] Gas turbine engines generally include a turbine and a rotor assembly. Gas turbine engines, such as turbofan engines, can be used for aircraft propulsion. In the case of a turbofan engine, the turbine includes a compressor section, a combustion section, and a turbine section in a serial flow order, and the rotor assembly is configured as a fan assembly.

[0003] During operation, air is compressed in the compressor section and mixed with fuel and ignited in the combustion section to generate combustion gases, which flow downstream through the turbine section. The turbine section extracts energy from the combustion gases to rotate the compressor section and fan assembly, thereby powering the gas turbine engine and propelling an aircraft incorporating such a gas turbine engine in flight.

[0004] The burner power is adjusted to meet the fan speed demand or thrust demand. The temperature of the burner of the combustion section may depend on the burner power and may be an operating limit of the gas turbine engine. Therefore, achieving the burner power may cause the burner temperature to change in a way that increases emissions. If the burner temperature is too low, carbon monoxide (CO) may increase. And, if the burner temperature is too high, nitrogen oxides (NO x ) may increase. Therefore, systems and methods that can achieve desired burner power while reducing emissions would be welcome in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] A full and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0006] Figure 1 is a cross-sectional view of a gas turbine engine according to an exemplary aspect of the present disclosure.

[0007] Figure 2 is a perspective view of an integrated fuel cell and combustor assembly according to the present disclosure.

[0008] Figure 3 yes Figure 2 A partially cutaway cross-sectional perspective view of a fuel cell stack with an integrated fuel cell and burner assembly.

[0009] Figure 4 is a schematic diagram of a gas turbine engine including an integrated fuel cell and combustor assembly according to an exemplary aspect of the present disclosure.

[0010] Figure 5 is a schematic diagram of a vehicle and propulsion system according to an exemplary aspect of the present disclosure.

[0011] Figure 6 is a cross-sectional view of an integrated fuel cell and combustor assembly according to an exemplary aspect of the present disclosure.

[0012] Figure 7 is a cross-sectional view of an integrated fuel cell and combustor assembly according to an exemplary aspect of the present disclosure.

[0013] Figure 8 is a cross-sectional view of an integrated fuel cell and combustor assembly according to an exemplary aspect of the present disclosure.

[0014] Figure 9 is a cross-sectional view of an integrated fuel cell and combustor assembly according to an exemplary aspect of the present disclosure. DETAILED DESCRIPTION

[0015] Reference will now be made in detail to the present embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and the description have been used to refer to like or similar parts of the disclosure.

[0016] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, all embodiments described herein are to be considered exemplary unless expressly stated otherwise.

[0017] For the purposes of the following description, the terms "upper," "lower," "right," "left," "vertical," "horizontal," "top," "bottom," "lateral," "longitudinal," and their derivatives shall relate to the embodiments as they are oriented in the accompanying drawings. However, it should be understood that the embodiments may assume various alternative variations unless expressly indicated to the contrary. It should also be understood that the specific devices shown in the drawings and described in the following specification are merely exemplary embodiments of the present disclosure. Accordingly, specific dimensions and other physical characteristics associated with the embodiments disclosed herein should not be considered limiting.

[0018] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of each component.

[0019] The terms "fore" and "aft" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, for a gas turbine engine, the front position refers to the position closer to the engine inlet, while the aft position refers to the position closer to the engine nozzle or exhaust.

[0020] The terms "upstream" and "downstream" refer to relative directions of fluid flow in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0021] Unless otherwise specified herein, the terms "coupled," "fixed," "attached," and the like refer to both direct coupling, fixing, or attachment as well as indirect coupling, fixing, or attachment through one or more intermediate components or features.

[0022] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0023] The term "at least one" in a context such as "at least one of A, B, and C" or "at least one of A, B, or C" means only A, only B, only C, or any combination of A, B, and C.

[0024] Approximating language, as used throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, values ​​modified by terms such as "about," "approximately," and "substantially" are not limited to the precise values ​​specified. In at least some instances, approximating language may correspond to the precision of an instrument used to measure a value, or the precision of a method or machine used to construct or manufacture a component and / or system. For example, approximately

[0025] Similar language may refer to within a margin of 1%, 2%, 4%, 10%, 15%, or 20%. These approximate margins may apply to a single 5 value, to margins defining either or both endpoints of a numerical range, and / or to a range between endpoints.

[0026] Here and throughout the specification and claims, range limitations are combined and interchanged, and unless context or language indicates otherwise, such ranges are identified and include all sub-ranges contained therein. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0027] As used herein, "tertiary flow" refers to a non-primary gas flow that can increase fluid energy to produce a small amount of total propulsion system thrust. The pressure ratio of the tertiary flow can be higher than the pressure ratio of the primary propulsion flow (e.g., bypass or propeller-driven propulsion flow).

[0028] Thrust may be generated through a dedicated nozzle or by mixing the airflow through the tertiary flow with the main propulsive or core flow (eg into a common nozzle).

[0029] In certain exemplary embodiments, the operating temperature of the air flow through the third stream may be lower than the maximum compressor temperature of the engine.

[0030] The exhaust temperature, and more specifically, can be less than 350 degrees Fahrenheit (such as less than 300 degrees Fahrenheit, such as less than 250 degrees Fahrenheit, such as less than 200 degrees Fahrenheit, and at least as high as the ambient temperature). In certain exemplary embodiments, this

[0031] These operating temperatures can promote heat transfer to or from the airflow through the third stream and the separate fluid stream. Furthermore, in certain exemplary embodiments, under takeoff conditions, or more specifically, under operating conditions of rated takeoff power at sea level, static flight speed, and an ambient temperature of 86 degrees Fahrenheit, the airflow through the third stream can contribute less than 50% of the total engine thrust (and at least, for example, 2% of the total engine thrust).

[0032] Furthermore, in certain exemplary embodiments, aspects of the air flow (e.g., air flow, mixing, or exhaust properties) of the third stream are also discussed.

[0033] mass), and thereby the above exemplary percentage contributions to total thrust, can be passively adjusted during engine operation or purposefully modified through the use of engine control features (such as fuel flow, electric motor power, variable stators, variable inlet guide vanes, valves, variable exhaust geometry, or flow characteristics) to adjust or optimize overall system performance over a wide range of potential operating conditions.

[0034] 5 The term "turbomachine" or "turbomachinery" means a machine that includes one or more compressors, generators,

[0035] A machine having a hot section (eg, a combustion section) and one or more turbines.

[0036] The term "gas turbine engine" refers to an engine having a turbine as all or part of its power source. Example gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, etc., as well as hybrid-electric versions of one or more of these engines.

[0037] When used with reference to compressors, turbines, shaft or spool components, etc., unless otherwise specified, the terms "low" and "high," or their respective comparatives (e.g., "lower" and "higher," as applicable), refer to relative speeds within the engine. For example, a "low turbine" or "low-speed turbine" defines a component that is configured to operate at a lower rotational speed (such as the maximum allowable rotational speed) than a "high turbine" or "high-speed turbine" at the engine.

[0038] The term "equivalence ratio" refers to the ratio of the actual fuel / air ratio to the stoichiometric fuel / air ratio. Stoichiometric combustion occurs when all of the oxygen is consumed in the reaction and no molecular oxygen (O2) is present in the products.

[0039] If the equivalence ratio is equal to one, combustion is stoichiometric. If it is less than one, combustion is lean (fuel-lean), with excess air, and if it is greater than one, combustion is rich (fuel-rich), with incomplete combustion. The equivalence ratio is the inverse of the air-fuel ratio.

[0040] The exhaust gas from an aircraft gas turbine engine consists of CO, carbon dioxide (CO2), water vapor (H2O), unburned hydrocarbons (UHC), particulate matter (primarily carbon), NO x and excess atmospheric oxygen and nitrogen.

[0041] As used herein, a "late lean injection system" may be generally described as a system for injecting a mixture of fuel and air into the working fluid stream at any point downstream of the main fuel nozzle of the combustor and upstream of the turbine. In certain embodiments, a "late lean injection system" is more specifically described as a system for injecting the fuel / air mixture into the aft end of the main combustion chamber defined by the liner. Generally speaking, one of the goals of a late lean injection system includes enabling fuel combustion to occur downstream of the main combustor / main combustion zone. This type of operation can be used to improve NO x performance.

[0042] If the burner temperature is too low, carbon monoxide (CO) may increase. If the burner temperature is too high, nitrogen oxides (NO x If the residence time in the flame zone is too long, it may increase NO x If the residence time in the flame zone is too short, CO may increase. The equivalence ratio at different locations of the burner also affects the emission output.

[0043] Systems and methods provide output products from a fuel cell to a combustion chamber of a gas turbine engine. Specifically, the output products can be provided according to a desired distribution of the output products. For example, the output products can be provided at a downstream location of the combustion chamber to reduce the residence time of the output products in the combustion chamber, thereby reducing emissions from the combustion chamber. Furthermore, the systems and methods described herein can provide a desired temperature distribution and / or distribution of the output products along the length of the combustion chamber. For example, the distribution of the output products can be determined so that the temperature along the length of the combustion chamber is within a low-emission temperature range. The output products can be provided at different locations along the length of the combustion chamber to move the temperature into a low-emission temperature range by increasing or decreasing the temperature, thereby reducing emissions.

[0044] Referring now to the drawings, in which like numerals refer to like elements throughout, Figure 1 A schematic cross-sectional view of an engine according to an exemplary embodiment of the present disclosure is provided. The engine can be incorporated into a vehicle. For example, the engine can be an aerospace engine incorporated into an aircraft. However, alternatively, the engine can be any other suitable type of engine for any other suitable vehicle.

[0045] For the depicted embodiment, the engine is configured as a high bypass gas turbine engine 100. Figure 1 As shown, the gas turbine engine 100 defines an axial direction A (extending parallel to a centerline axis 101 for reference), a radial direction R, and a circumferential direction (extending about the axial direction A; not shown in FIG. Figure 1 ). Generally, the gas turbine engine 100 includes a fan section 102 and a turbine 104 disposed downstream of the fan section 102 .

[0046] The depicted exemplary turbomachine 104 generally includes a substantially tubular casing 106 defining an annular inlet 108. Casing 106 encloses, in serial flow relationship, a compressor section, including a boost or low-pressure (LP) compressor 110 and a high-pressure (HP) compressor 112; a combustion section 114; a turbine section, including a high-pressure (HP) turbine 116 and a low-pressure (LP) turbine 118; and an exhaust nozzle section 120. The compressor section, combustion section 114, and turbine section together at least partially define a core air flow path 121 extending from annular inlet 108 to exhaust nozzle section 120. The turbofan engine further includes one or more drive shafts. More specifically, the turbofan engine includes a high-pressure (HP) shaft or spool 122 drivingly connecting HP turbine 116 to HP compressor 112, and a low-pressure (LP) shaft or spool 124 drivingly connecting LP turbine 118 to LP compressor 110.

[0047] For the depicted embodiment, fan section 102 includes a fan 126 having a plurality of fan blades 128 coupled to a disk 130 in a spaced-apart manner. Fan blades 128 and disk 130 are rotatable together about centerline axis 101 via LP shaft 124. Disk 130 is covered by a rotatable forward hub 132 aerodynamically shaped to facilitate airflow through the plurality of fan blades 128. In addition, an annular fan case or outer nacelle 134 is disposed circumferentially surrounding fan 126 and / or at least a portion of turbine 104. Nacelle 134 is supported relative to turbine 104 by a plurality of circumferentially spaced outlet guide vanes 136. A downstream section 138 of nacelle 134 extends over an outer portion of turbine 104 to define a bypass airflow passage 140 therebetween.

[0048] In this manner, it will be understood that the gas turbine engine 100 generally includes a first flow (e.g., core air flow path 121) and a second flow (e.g., bypass airflow passage 140) extending parallel to the first flow. In certain exemplary embodiments, the gas turbine engine 100 may further define a third flow, for example, extending from the LP compressor 110 to the bypass airflow passage 140 or to the environment. With this configuration, the LP compressor 110 may generally include a first compressor stage configured as a ducted mid-fan and a downstream compressor stage. An inlet for the third flow may be positioned between the first compressor stage and the downstream compressor stage.

[0049] Still refer to Figure 1 , the gas turbine engine 100 further includes an accessory gearbox 142 and a fuel delivery system 146. For the embodiment shown, the accessory gearbox 142 is located within the shroud / casing 106 of the turbine 104. Furthermore, it will be understood that for Figure 1In the embodiment schematically depicted in FIG, an accessory gearbox 142 is mechanically coupled to one or more shafts or spools of the turbine 104 and is capable of rotating together with the one or more shafts or spools of the turbine 104. For example, in the depicted exemplary embodiment, the accessory gearbox 142 is mechanically coupled to the HP shaft 122 via a suitable gear train 144 and is capable of rotating together with the HP shaft 122. The accessory gearbox 142 can provide power to one or more suitable accessory systems of the gas turbine engine 100 during at least some operations and can further provide power back to the gas turbine engine 100 during other operations. For example, for the illustrated embodiment, the accessory gearbox 142 is coupled to a starter motor / generator 152. The starter motor / generator can be configured to extract power from the accessory gearbox 142 and the gas turbine engine 100 during certain operations to generate electricity and can provide power back to the accessory gearbox 142 and the gas turbine engine 100 (e.g., to the HP shaft 122) during other operations to add mechanical work back to the gas turbine engine 10 (e.g., for starting the gas turbine engine 100).

[0050] In addition, the fuel delivery system 146 generally includes a fuel source 148 (such as a fuel tank) and one or more fuel delivery lines 150. The one or more fuel delivery lines 150 provide a flow of fuel through the fuel delivery system 146 to the combustion section 114 of the turbine 104 of the gas turbine engine 100. As will be discussed in more detail below, the combustion section 114 includes an integrated fuel cell and combustor assembly 200. For the depicted embodiment, the one or more fuel delivery lines 150 provide a flow of fuel to the integrated fuel cell and combustor assembly 200.

[0051] However, it will be understood that Figure 1 The exemplary gas turbine engine 100 depicted in FIG is provided as an example only. In other exemplary embodiments, any other suitable gas turbine engine may be used with aspects of the present disclosure. For example, in other embodiments, the turbofan engine may be any other suitable gas turbine engine, such as a turboshaft engine, a turboprop engine, a turbojet engine, etc. In this manner, it will be further understood that in other embodiments, the gas turbine engine may have any other suitable configuration, such as any other suitable number or arrangement of shafts, compressors, turbines, fans, etc. Additionally, although Figure 1The exemplary gas turbine engine depicted in FIG is schematically shown as a direct drive fixed pitch turbofan engine, but in other embodiments, the gas turbine engine of the present disclosure may be a geared gas turbine engine (i.e., including a gearbox between the fan 126 and a shaft driving the fan (such as the LP shaft 124)), a variable pitch gas turbine engine (i.e., including a fan 126 having a plurality of fan blades 128 that are rotatable about their respective pitch axes), etc. Furthermore, while the exemplary gas turbine engine 100 includes a ducted fan 126, in other exemplary aspects, the gas turbine engine 100 may include a non-ducted fan 126 (or an open rotor fan) without a nacelle 134. Furthermore, although not depicted herein, in other embodiments, the gas turbine engine may be any other suitable type of gas turbine engine, such as a marine gas turbine engine.

[0052] Now refer to Figure 2 , schematically illustrating a portion of the combustion section 114 according to an embodiment of the present disclosure, which includes Figure 1 The gas turbine engine 100 (described above with respect to Figure 1 A portion of an integrated fuel cell and combustor assembly 200 for use in a gas turbine engine 100 is depicted.

[0053] It will be appreciated that combustion section 114 includes a compressor diffuser nozzle 202 and generally extends between upstream and downstream ends in an axial direction A. Combustion section 114 is fluidly coupled to the compressor section at the upstream end via the compressor diffuser nozzle 202 and to the turbine section at the downstream end.

[0054] The integrated fuel cell and combustor assembly 200 generally includes a fuel cell assembly 204 ( Figure 2 only partially depicted in ; see also Figures 3 and 4 ) and a combustor 206. The combustor 206 includes an inner liner 208, an outer liner 210, a dome assembly 212, a cover assembly 214, a swirler assembly 216, and a fuel flow line 218. The combustion section 114 generally includes a casing 220 outside the combustor 206 in the radial direction R5 to surround the combustor 206, and a

[0055] Inner shell 222.

[0056] Inner shell 222 and inner liner 208 define an inner passageway 224 therebetween, while outer shell 220 and outer liner 210 define an outer passageway 226 therebetween. Inner shell 222, outer shell 220, and dome assembly 212 together at least partially define a combustion chamber 228 of combustor 206.

[0057] The dome assembly 212 is disposed proximate the upstream end of the combustion section 114 (ie, closer to the upstream end than the downstream end) and includes an opening 229 for receiving and retaining the swirler assembly 216. The swirler assembly 216 also includes an opening 229 for receiving and retaining the swirler assembly 216.

[0058] Keep fuel flow line 218 open.

[0059] The fuel flow line 218 is further coupled to a fuel source 148 disposed outside the housing 220 in the radial direction R (see FIG. Figure 1 ) and is configured to receive fuel from fuel source 148. In this manner, fuel flow line 218 can be fluidly coupled to the fuel source 148 described above with reference to FIG. Figure 1 One or more fuel delivery lines 150 are depicted.

[0060] The cyclone assembly 216 may include a plurality of cyclones (not shown) configured to swirl the compressed fluid.

[0061] The compressed fluid is swirled prior to injection into the combustion chamber 228 to generate combustion gases. In the illustrated embodiment, the shroud assembly 214 is configured to hold the inner liner 208, the outer liner 210, the swirler assembly 216, and the dome assembly 212 together.

[0062] During operation, the compressor diffuser nozzle 202 is configured to direct the compressed fluid 230 from the compressor section to the combustion chamber.

[0063] The combustor 206 is configured to mix the compressed fluid 230 with the fuel within the swirler assembly 216 and combust within the combustion chamber 2280 to generate combustion gases. The combustion gases are provided to the turbine section to drive one or more turbines (e.g., the high-pressure turbine 116 and the low-pressure turbine 118) of the turbine section.

[0064] During operation of the gas turbine engine 100 including the integrated fuel cell and combustor assembly 200, the flame within the combustion chamber 228 is maintained by a continuous flow of fuel and air.

[0065] To ignite the fuel and air, the integrated fuel cell and burner assembly 200 further includes an igniter 231. The igniter 231 can provide a spark or initial flame to ignite the fuel and air mixture within the combustion chamber 228. In certain exemplary embodiments

[0066] , the integrated fuel cell and burner assembly 200 may additionally include a dedicated fuel cell igniter 233 (depicted in dashed lines). Figure 2In some embodiments, the dedicated fuel cell igniter 233 is positioned downstream of at least a portion of the fuel cell, and in particular, downstream of at least a portion of the fuel cell stack (described below). In this manner, the dedicated fuel cell igniter 233 can more efficiently combust the output products of the fuel cell.

[0067] 0 as above and Figure 2 , the integrated fuel cell and combustor assembly 200 further includes a fuel cell assembly 204. The fuel cell stacks 232, 234 (e.g., fuel and air conditioning devices) of the fuel cell assembly 204 can be cylindrical (e.g., not necessarily circular in cross-section) and surround an outer liner 210 (e.g., such as a cylindrical outer liner 210) of the combustion chamber 228. Figure 3 The fuel cell stack 232 is shown extending or extending within the liner 208 of the combustion chamber 228 (eg, fuel cell stack 234 ).

[0068] For example, the combustor 206 is an annular combustor, and the fuel cell stack 232 of the fuel cell assembly 204 extends around (or is integrated with) the outer liner 210 or casing (e.g., housing 220) of the combustor 206 that defines the combustion chamber 228. This configuration will be described below with reference to Figure 3 Discussed further and shown in more detail.

[0069] Additionally or alternatively, the fuel cell stack 234 of the fuel cell assembly 204 extends within (or is integrated with) a liner 208 or casing (eg, inner shell 222 ) of the combustor 206 that defines the combustion chamber 228 .

[0070] exist Figure 2 In embodiments, the fuel cell stacks 232 , 234 may be part of the same fuel cell assembly 204 (eg, share common structure and components that facilitate operation of the fuel cell assembly 204 ).

[0071] Alternatively, however, in other exemplary embodiments, the first fuel cell stack 232 may be part of a first fuel cell assembly and the second fuel cell stack 234 may be part of a second fuel cell assembly (eg, each having separate components to facilitate operation).

[0072] The operation of the fuel cell assembly 204 , and more specifically, the operation of the fuel cell stacks 232 , 234 of the fuel cell assembly 204 , will be described in greater detail below.

[0073] For the depicted embodiment, the fuel cell assembly 204 is configured as a solid oxide fuel cell ("SOFC") assembly, including a SOFC fuel cell stack (eg, having a plurality of SOFCs arranged in a circumferential direction).

[0074] It will be understood that a SOFC is generally an electrochemical conversion device that generates electricity directly by oxidizing a fuel. Fuel cell components in general, and fuel cells in particular, are characterized by the electrolyte materials used. The SOFCs disclosed herein generally may include solid oxide or ceramic electrolytes. Such fuel cells generally exhibit high combined thermoelectric efficiency, long-term stability, fuel flexibility, and low emissions.

[0075] Furthermore, in other exemplary embodiments, the fuel cell assembly 204 may include any other suitable number and arrangement of fuel cell stacks 232 , 234 to distribute output products at various locations along the axial and circumferential directions of the combustion chamber 228 with different parameters (e.g., temperature, pressure, composition, etc.).

[0076] The exemplary fuel cell assembly 204 further includes power converters 236, 238. The fuel cell assembly 204 is in electrical communication with the power converters 236, 238 via a plurality of power cables (not labeled).

[0077] The power converters 236, 238 control the current drawn from the respective fuel cell stacks 232, 234 of the fuel cell assembly 204 and can convert power from direct current ("DC") power to DC power at another voltage level or alternating current ("AC") power. Similarly, in embodiments including multiple fuel cell assemblies, described in more detail below, each fuel cell assembly can have an associated power converter that controls the current drawn from the fuel cell assembly and can convert power from DC power to DC power at another voltage level or AC power. The first power converter 236, the second power converter 238, and any other power converters can be electrically coupled to an electrical bus (such as the electrical bus 326 described below).

[0078] The integrated fuel cell and combustor assembly 200 further includes a fuel cell controller 240 that is in operative communication with the first power converter 236 and the second power converter 238 to, for example, send and receive communications and signals therebetween. For example, the fuel cell controller 240 can send current or power setpoint signals to the first power converter 236 and the second power converter 238 and can receive voltage or current feedback signals, for example, from the first power converter 235 and the second power converter 238. Figure 4 The fuel cell controller 240 is further described.

[0079] In certain embodiments described in further detail below, the fuel cell assembly 204 includes a plurality of fuel cell stacks distributed along an axial direction A of the combustor 206. Fuel to the plurality of fuel cell stacks may be varied (e.g., from the fuel source 148 or by elements of the fuel cell and combustor assembly 200 described herein) to distribute output products or fuel to the combustor 206 along the axial direction A of the combustor 206.

[0080] For example, a “late lean” approach uses more fuel burned at the downstream end of the combustor 206. The “late lean” approach may be implemented to reduce the residence time of the fuel in the combustor 206.

[0081] As will be discussed in more detail below, a fuel cell is an electrochemical device that can convert chemical energy from a fuel (such as hydrogen) into electrical energy through an electrochemical reaction of the fuel with an oxidant (such as oxygen contained in the atmosphere). Fuel cell systems can be advantageously used as energy supply systems because they can be considered environmentally superior and efficient when compared to at least some existing systems.

[0082] To improve system efficiency and fuel utilization and reduce external water consumption, the fuel cell system may include an anode recirculation loop. Since a single fuel cell can only generate a voltage of about 1V, multiple fuel cells may be stacked together (which may be referred to as a fuel cell stack) to generate the desired voltage. Fuel cells may include solid oxide fuel cells (SOFCs), molten carbonate fuel cells (MCFCs), phosphoric acid fuel cells (PAFCs), and proton exchange membrane fuel cells (PEMFCs), which are generally named after their respective electrolytes.

[0083] It will be appreciated that in at least some exemplary embodiments, the fuel cell stacks 232, 234 may extend substantially 360 degrees in the circumferential direction C of the gas turbine engine (i.e., a direction extending about the centerline axis 101 of the gas turbine engine 100). Figure 3 , depicts a cross-sectional cutaway perspective view of a fuel cell stack 232 according to an exemplary embodiment of the present disclosure. Additional fuel cell assemblies, described in greater detail below, can be constructed in a similar manner.

[0084] As shown, the fuel cell stack 232 extends around the outer liner 210 of the combustion chamber 228 in a circumferential direction C and, in the embodiment shown, completely surrounds the outer liner 210 of the combustion chamber 288 around the centerline axis 101. More specifically, the fuel cell stack 232 (e.g., a plurality of fuel cells coupled together is referred to as a fuel cell stack) is arranged along the circumferential direction C. Figure 3The fuel cells of the fuel cell stack 232 can be arranged as a single ring or cylinder. As described in further detail below, the fuel cell stack 232 can have a Figure 2 In another example, multiple additional rings of fuel cells can be placed on top of or outside of each other (e.g., radially stacked or concentrically arranged) to form a fuel cell stack 232 having an elongated length in the radial direction R.

[0085] As will be explained in more detail below, reference Figure 4 , the fuel cell stack 232 is positioned to receive exhaust air 244 from, for example, the compressor section and fuel 246 from the fuel delivery system 146. The fuel cell stack 232 may include grooves 247 around the outside of the fuel cell stack 232. The grooves 247 receive the air 244 and the fuel 246 and direct and distribute the air 244 and the fuel 246 around the outer surface of the fuel cell stack 232 and into the fuel cell stack 232.

[0086] In the case of the fuel cell stack 234, the grooves 247 surround the inside of the fuel cell stack 234. Here, the grooves 247 receive the air 244 and the fuel 246 and guide and distribute the air 244 and the fuel 246 around the inner surface of the fuel cell stack 234 and into the fuel cell stack 234.

[0087] The fuel cell stack 232 uses the air 244 and at least some of the fuel 246 to generate electricity and directs the partially oxidized fuel and the unused portion of the air (eg, output products 248) radially into the combustion chamber 228 ( Figure 2 ) in. Burner 206 ( Figure 2 ) combusts partially oxidized fuel and air (e.g., output product 248) in the combustion chamber 228 into combustion gases, which are directed downstream into the turbine section to drive or assist in driving one or more turbines therein.

[0088] Figure 3 The fuel cell stack 232 depicted in FIG may include a housing 250 having a combustion outlet side 252 and a fuel and air inlet side 254 opposite the combustion outlet side 522, and sides 256, 258. Side 258 is Figure 3 Not visible in the stereogram.

[0089] It will be appreciated that the fuel cell stack 232 may alternatively include a plurality of fuel cell stacks “stacked” side-by-side or concentrically, for example.

[0090] The combustion outlet side 252 includes a plurality of combustion outlets 264, and the fuel and air inlet side 254 includes a plurality of fuel and air inlets 266. In the case where the fuel cell stack 232 is integrated with the liner of the combustion chamber 228, the combustion outlet side 252 can be the outer liner 210 of the combustion chamber 228. Alternatively, the outer liner 210 of the combustion chamber can have openings 271, and the output products 248 directed out of the combustion outlets 264 are directed to move through the openings 271 and into the combustion chamber 228.

[0091] The groove 247 includes one or more fuel inlets 268 and one or more air inlets 270. Optionally, one or more of the inlets 268, 270 can be on the other side of the housing 250. Each of the one or more fuel inlets 268 is fluidly coupled to a fuel source of the fuel cell stack 232 (such as one or more pressurized containers of a hydrogen-containing gas or a fuel processing unit described further below). Each of the one or more air inlets 270 is fluidly coupled to an air source of the fuel cell stack 232 (such as air exhausted from a compressor section and / or an air processing unit described further below). The inlets 268, 270 separately receive fuel and air from external fuel and air sources and separately direct the fuel and air into the fuel cell stack 232.

[0092] During operation, the grooves 247 receive air 244 and fuel 246 and direct and distribute the air 244 and fuel 246 around the fuel and air inlet side 254 of the fuel cell stack 232 and into the fuel cell stack 232 through the fuel and air inlet 266. The fuel cell stack 232 generates output products and output products 248 (e.g., partially oxidized fuel and air) (also referred to herein as "combustion gases"). The output products 248 are generated using fuel and air that are not consumed by the fuel cell 204.

[0093] The output products 248 are directed from the combustion outlet 264 out of the combustion outlet side 252 of the casing 250, for example, through openings 271 in the liner of the combustion chamber 228. The output products 248 are provided to the combustion chamber 228 and combusted during operation to generate combustion gases that are used to generate thrust for the gas turbine engine 100 (and a vehicle / aircraft incorporating the gas turbine engine 100).

[0094] In certain exemplary embodiments, the fuel cell stack 232 can be constructed in a manner similar to one or more of the exemplary fuel cell systems (labeled 108) described, for example, in U.S. patent application publication No. 2019 / 0136761A1, filed on November 7, 2017, the entire contents of which are incorporated herein by reference.

[0095] In certain exemplary embodiments, the fuel cell stack 242 can be constructed in a manner similar to one or more of the exemplary fuel cell systems (labeled 100) described, for example, in U.S. patent application publication No. 2020 / 0194799A1, filed on December 17, 2018, the entire contents of which are incorporated herein by reference.

[0096] Now refer to Figure 4 , the operation of the integrated fuel cell and burner assembly 200 according to an exemplary embodiment of the present disclosure will be described. More specifically, Figure 4 A schematic diagram of a gas turbine engine 100 and an integrated fuel cell and combustor assembly 200 according to an embodiment of the present disclosure is provided. In certain exemplary embodiments, the gas turbine engine 100 and the integrated fuel cell and combustor assembly 200 may be configured in a manner similar to that of FIG. Figures 1 to 3 One or more exemplary embodiments are constructed in a similar manner.

[0097] Thus, it will be understood that gas turbine engine 100 generally includes fan section 102 having fan 126, LP compressor 110, HP compressor 112, combustion section 114, HP turbine 116, and LP turbine 118. Combustion section 114 generally includes integrated fuel cell and combustor assembly 200 having combustor 206 and fuel cell assembly 204.

[0098] The propulsion system including the gas turbine engine 100 further includes a fuel delivery system 146. The fuel delivery system 146 generally includes a fuel source 148 and one or more fuel delivery lines 150. The fuel source 148 may include a supply of fuel (e.g., hydrocarbon fuel, including, for example, carbon-neutral fuel or synthetic hydrocarbons) for the gas turbine engine 100. Furthermore, it will be understood that the fuel delivery system 146 also includes a fuel pump 272 and a flow divider 274, and that the one or more fuel delivery lines 150 include a first fuel delivery line 150A, a second fuel delivery line 150B, and a third fuel delivery line 150C.

[0099] The flow splitter 274 divides the fuel flow from the fuel source 148 and the fuel pump 272 into a first fuel flow through the first fuel delivery line 150A to the fuel cell assembly 204 (and in particular to the fuel processing unit described below), a second fuel flow through the second fuel delivery line 150B also to the fuel cell assembly 204 (and in particular to the air handling unit described below), and a third fuel flow through the third fuel delivery line 150C to the burner 206.

[0100] The flow divider 274 may include a series of valves (not shown) to facilitate this diversion of the fuel flow from the fuel source 148, or alternatively, may have a fixed geometry. Furthermore, for the illustrated embodiment, the fuel delivery system 146 includes a first fuel valve 151A associated with the first fuel delivery line 150A (e.g., for controlling a first fuel flow), a second fuel valve 151B associated with the second fuel delivery line 150B (e.g., for controlling a second fuel flow), and a third fuel valve 151C associated with the third fuel delivery line 150C (e.g., for controlling a third fuel flow).

[0101] Gas turbine engine 100 further includes a compressor discharge system and an air flow delivery system. More specifically, the compressor discharge system includes an LP bleed air duct 276 and an associated LP bleed air valve 278 , an HP bleed air duct 280 and an associated HP bleed air valve 282 , and an HP outlet air duct 284 and an associated HP outlet air valve 286 .

[0102] The gas turbine engine 100 further includes an air flow supply conduit 288 (in air flow communication with an air flow supply 290) and an associated air valve 292, which are also in air flow communication with the air flow delivery system for providing compressed air to the fuel cell assembly 204 of the integrated fuel cell and combustor assembly 200. The air flow supply may be, for example, a second gas turbine engine configured to provide cross-bleed air, an auxiliary power unit (APU) configured to provide bleed air, a ram air turbine (RAT), etc. The air flow supply may supplement the compressor bleed system if the compressor air source is insufficient or unavailable.

[0103] The compressor discharge system (and gas flow supply conduit 288 ) is in gas flow communication with the gas flow delivery system for providing a compressed gas flow to the fuel cell assembly 204 , as will be explained in greater detail below.

[0104] Still refer to Figure 4 The fuel cell assembly 204 of the integrated fuel cell and burner assembly 200 includes a fuel cell stack 232 that can be constructed in a manner similar to, for example, the fuel cell stack 232 described above. The fuel cell stack 232 is schematically depicted as a single fuel cell having a cathode side 296, an anode side 298, and an electrolyte 300 positioned therebetween. It will be generally understood that the electrolyte 300 can conduct negative oxygen ions from the cathode side 296 to the anode side 298 during operation to generate electrical current and electricity.

[0105] The anode side 298 can support an electrochemical reaction that generates electricity. The fuel can be oxidized in the anode side 298 using oxygen ions received from the cathode side 296 via diffusion through the electrolyte 300. This reaction can generate heat, steam, and electricity in the form of free electrons in the anode side 298, which can be used to power energy consumption devices (such as one or more additional electrical devices 328 described below). Electrons returned from the energy consumption devices to the cathode side 296 can be used to generate oxygen ions via oxygen reduction of the cathode oxidant.

[0106] The cathode side 296 can be coupled to a cathode oxidant source, such as atmospheric oxygen. The cathode oxidant is defined as the oxidant supplied to the cathode side 296, which the fuel cell system uses when generating electricity. The cathode side 296 can be permeable to oxygen ions received from the cathode oxidant.

[0107] Electrolyte 300 may be in communication with anode side 298 and cathode side 296. Electrolyte 300 may allow oxygen ions to pass from cathode side 296 to anode side 298 and may have little or no conductivity to prevent free electrons from passing from cathode side 296 to anode side 298.

[0108] The anode side of a solid oxide fuel cell (such as the fuel cell stack 232) can be composed of a nickel / yttria-stabilized zirconia (Ni / YSZ) cermet. The nickel in the anode side serves as a catalyst for fuel oxidation and a current conductor. During normal operation of the fuel cell stack 232, the operating temperature can be greater than or equal to about 700° C., and the nickel (Ni) in the anode remains in its reduced form due to the continuous supply of primarily hydrogen fuel gas. Other configurations are also contemplated.

[0109] Briefly, it will be understood that the fuel cell assembly 204 further includes a fuel cell sensor 302 that is configured to sense data indicative of fuel cell assembly operating parameters such as the temperature of the fuel cell stack 232 (e.g., the cathode side 296 or the anode side 298 of the fuel cell), the pressure within the fuel cell stack 232 (e.g., within the cathode side 296 or the anode side 298 of the fuel cell).

[0110] The fuel cell stack 232 is disposed downstream of the LP compressor 110, the HP compressor 112, or both. Figure 2As will be understood from the description of FIG, the fuel cell stack 232 can be coupled to or otherwise integrated with a liner of the combustor 206 (e.g., the outer liner 210 or the inner liner 208 for the fuel cell stack 234). In this manner, the fuel cell stack 232 can also be disposed upstream of the combustion chamber 228 of the integrated fuel cell and combustor assembly 200, and further upstream of the HP turbine 116 and the LP turbine 118.

[0111] like Figure 4 As shown, fuel cell assembly 204 also includes a fuel processing unit 304 (e.g., a fuel and air premixing device) and an air processing unit 306. In the exemplary embodiment depicted, fuel processing unit 304 and air processing unit 306 are manifolded together within housing 308 to provide conditioned air and fuel to fuel cell stack 232.

[0112] The fuel processing unit 304 may be any suitable structure for generating a hydrogen-rich fuel stream. For example, the fuel processing unit 304 may include a fuel reformer or a catalytic partial oxidation converter (CPO x ) for generating a hydrogen-rich fuel flow for the fuel cell stack 232.

[0113] However, it should be understood that the fuel processing unit 304 may additionally or alternatively include any suitable type of fuel reformer, such as an autothermal reformer and a steam reformer, which may require an additional steam inlet flow with a higher hydrogen content at the reformer outlet flow. Additionally or alternatively, the fuel processing unit 304 may also include a reformer integrated with the fuel cell stack 232.

[0114] The air handling unit 306 may be any suitable structure for raising the temperature of the air supplied thereto to a temperature high enough to achieve fuel cell temperature control (e.g., about 600° C. to about 800° C.). For example, in the depicted embodiment, the air handling unit includes a pre-combustor system that operates based on the flow of fuel through the second fuel delivery line 150B and is configured to increase the temperature of the air through combustion, for example, during transient conditions (such as startup, shutdown, and abnormal situations).

[0115] Similarly, it should be understood that Figure 4 The air handling unit 306 may alternatively be a heat exchanger or another device for raising the temperature of the air provided thereto to a temperature high enough to achieve fuel cell temperature control (eg, about 600° C. to about 800° C.).

[0116] As described above, the compressor discharge system (and the airflow supply conduit 288) is in airflow communication with the airflow delivery system for providing compressed airflow to the fuel cell assembly 204. The airflow delivery system includes an anode airflow conduit 310 and an associated anode airflow valve 312 for providing airflow to the fuel processing unit 304, a cathode airflow conduit 314 and an associated cathode airflow valve 316 for providing airflow to the air handling unit 306, and a cathode bypass air conduit 318 and an associated cathode bypass air valve 320 for providing airflow directly to the fuel cell stack 232 (or more specifically, to the cathode side 296 of the fuel cells).

[0117] The fuel delivery system 146 is configured to provide a first fuel flow to the fuel processing unit 304 via a first fuel delivery line 150A and a second fuel flow (eg, as fuel for a pre-combustor system, if provided) to the air handling unit 306 via a second fuel delivery line 150B.

[0118] Fuel cell stack 232 outputs generated electricity as fuel cell power output 322. Additionally, fuel cell stack 232 directs cathode air exhaust and anode fuel exhaust (eg, output products, neither labeled for clarity) into combustion chamber 228 of combustor 206.

[0119] In operation, the air handling unit 306 is configured to heat / cool a portion of the compressed air entering through the cathode air flow conduit 314 to generate processed air to be directed into the fuel cell stack 232, thereby facilitating the operation of the fuel cell stack 232. The air handling unit 306 receives a second fuel stream from the second fuel delivery line 150B and can, for example, combust this second fuel stream to heat the received air to a desired temperature (e.g., approximately 600° C. to approximately 800° C.) to facilitate the operation of the fuel cell stack 232. The air processed by the air handling unit 306 is directed into the fuel cell stack 232. In an embodiment of the present disclosure, as shown, the cathode bypass air conduit 318 and the air processed by the air handling unit 306 can be combined into a combined air stream to be delivered to the cathode 296 of the fuel cell stack 232.

[0120] In addition, if Figure 4 , the first fuel flow through the first fuel delivery line 150A is directed to the fuel processing unit 304 for use in producing a hydrogen-rich fuel flow (e.g., optimizing the hydrogen content of the fuel flow) to also be fed into the fuel cell stack 232. It will be appreciated, and as discussed below, that the flow of air (process air and bypass air) to the fuel cell stack 232 (e.g., cathode side 296) and the fuel from the fuel processing unit 304 to the fuel cell stack 232 (e.g., anode side 298) can facilitate power generation.

[0121] Because the inlet air to the fuel cell stack 232 may come solely from the upstream compressor section, without any other separately controlled air source, it will be understood that the inlet air to the fuel cell stack 232 exhausted from the compressor section may be subject to variations in air temperature that occur during different phases of flight. By way of illustrative example only, the air within a particular location in the compressor section of the gas turbine engine 100 may operate at 200° C. during idle, 600° C. during takeoff, 268° C. during cruise, and so on. This type of temperature variation in the inlet air directed to the fuel cell stack 232 may cause significant thermal transient issues (or even thermal shock) to the ceramic materials of the fuel cell stack 232, which may range from cracking to failure.

[0122] Therefore, by fluidly connecting the air handling unit 306 between the compressor section and the fuel cell stack 232, the air handling unit 306 can be used as a control device or system to maintain the air processed by the air handling unit 306 and directed to the fuel cell stack 232 within a desired operating temperature range (e.g., plus or minus 100°C, or preferably plus or minus 50°C, or plus or minus 20°C). In operation, the temperature of the air provided to the fuel cell stack 232 (relative to the temperature of the air exhausted from the compressor section) can be controlled by controlling the fuel flow to the air handling unit 306. By increasing the fuel flow to the air handling unit 306, the temperature of the airflow to the fuel cell stack 232 can be increased. By decreasing the fuel flow to the air handling unit 306, the temperature of the airflow to the fuel cell stack 232 can be decreased. Alternatively, fuel can be disabled to prevent the air handling unit 306 from increasing and / or decreasing the temperature of the air exhausted from the compressor section and directed to the air handling unit 306.

[0123] In addition, as depicted in dashed lines, the fuel cell assembly 204 further includes an air flow bypass conduit 321 extending around the fuel cell stack 232 to allow some or all of the air flow conditioned by the air handling unit 306 (and combined with any bypass air passing through the conduit 318) to bypass the cathode side 296 of the fuel cell stack 232 and enter the combustion chamber 228 directly. The air flow bypass conduit 321 can be in thermal communication with the fuel cell stack 232. The fuel cell assembly further includes a fuel bypass conduit 323 extending around the fuel cell stack 232 to allow some or all of the reformed fuel from the fuel processing unit 304 to bypass the anode side 298 of the fuel cell stack 232 and enter the combustion chamber 228 directly.

[0124] As briefly mentioned above, the fuel cell stack 232 converts the anode fuel stream from the fuel processing unit 304 and the air processed by the air processing unit 306, which are sent to the fuel cell stack 232, into electrical energy in the form of DC current, i.e., the fuel cell power output 322. The fuel cell power output 322 is directed to the power converter 236 to convert the DC current into DC current or AC current that can be effectively used by one or more subsystems.

[0125] For the depicted embodiment, electrical power is provided from the power converter to an electrical bus 326. The electrical bus 326 may be an electrical bus dedicated to the gas turbine engine 100, an electrical bus of an aircraft incorporating the gas turbine engine 100, or a combination thereof. The electrical bus 326 is in electrical communication with one or more additional electrical devices 328, which may be adapted to draw electrical current from the fuel cell stack 294 or apply an electrical load to the fuel cell stack 232.

[0126] The one or more additional electrical devices 328 may be a power source, a power sink, or both. For example, the additional electrical device 328 may be a power storage device (such as one or more batteries), an electric machine (a generator, an electric motor, or both), an electric propulsion device, etc. For example, the one or more additional electrical devices 328 may include a starter motor / generator for the gas turbine engine 100.

[0127] Still refer to Figure 4 The gas turbine engine 100 further includes a sensor 330. In the illustrated embodiment, the sensor 330 is configured to sense data indicative of a flame within the combustion section 114 of the gas turbine engine 100. For example, the sensor 330 may be a temperature sensor configured to sense data indicative of an outlet temperature of the combustion section 114, an inlet temperature of the turbine section, an exhaust temperature, or a combination thereof. Additionally or alternatively, the sensor 330 may be any other suitable sensor or any suitable combination of sensors configured to sense one or more gas turbine engine operating conditions or parameters, including data indicative of a flame within the combustion section 114 of the gas turbine engine 100.

[0128] In addition, if Figure 4 As further schematically depicted in , the propulsion system, the aircraft including the propulsion system, or both include a controller 240. For example, the controller 240 can be a stand-alone controller, a gas turbine engine controller (e.g., a full authority digital engine controller or FADEC controller), an aircraft controller, a supervisory controller for the propulsion system, combinations thereof, and the like.

[0129] The controller 240 is operably connected to various sensors, valves, etc. within at least one of the gas turbine engine 100, the fuel delivery system 146, and the fuel cell and combustor assembly 200. More specifically, for the exemplary aspect depicted, the controller 240 is operably connected to the air handling unit 306, the fuel processing unit 304, the power converter 236 (and / or the power converter 238), valves of the axially distributed fuel cell stack (e.g., air and fuel valves to the fuel cell stack discussed below), valves of the compressor discharge system (valves 278, 282, 286), valves of the air flow delivery system (valves 312, 316, 320), and valves of the fuel delivery system 146 (diverter 274, valves 151A, 151B, 151C), as well as the gas turbine engine 100 sensor 330 and the fuel cell sensor 302.

[0130] It will be understood from the following description that the controller 240 can communicate with these components by wire or wirelessly. In this way, the controller 240 can receive inputs from various sources (including Figure 4 , the supervisory controller 412, the gas turbine engine sensors 330, and the fuel cell sensors 302 shown in FIG, can make control decisions and can provide data (e.g., instructions) to various outputs (including valves of a compressor discharge system that controls the discharge of airflow from the compressor section, an airflow delivery system that directs the airflow discharged from the compressor section, and a fuel delivery system 146 that directs the flow of fuel within the gas turbine engine 100).

[0131] With particular reference to the operation of the controller 240, in at least some embodiments, the controller 240 may include one or more computing devices 332. The computing devices 332 may include one or more processors 332A and one or more memory devices 332B. The one or more processors 332A may include any suitable processing device, such as a microprocessor, a microcontroller, an integrated circuit, a logic device, and / or other suitable processing device. The one or more memory devices 332B may include one or more computer-readable media, including, but not limited to, non-transitory computer-readable media, RAM, ROM, a hard drive, a flash drive, and / or other memory devices.

[0132] One or more memory devices 332B may store information accessible by one or more processors 332A, including computer-readable instructions 332C executable by one or more processors 332A. Instructions 332C may be any set of instructions that, when executed by one or more processors 332A, cause one or more processors 332A to perform operations. In some embodiments, instructions 332C may be executed by one or more processors 332A to cause one or more processors 332A to perform operations such as any operations and functions for which controller 240 and / or computing device 332 are configured, operations for operating a propulsion system as described herein, and / or any other operations or functions of one or more computing devices 332. Instructions 332C may be software written in any suitable programming language or may be implemented in hardware.

[0133] Additionally or alternatively, instructions 332C may be executed in logically and / or virtually separate threads on processor 332A. Memory device 332B may further store data 332D accessible by processor 332A. For example, data 332D may include data indicating power flow, data indicating gas turbine engine 100 / aircraft operating conditions, and / or any other data and / or information described herein.

[0134] The computing device 332 also includes a network interface 332E, which is configured to communicate, for example, with other components of the gas turbine engine 100 (such as valves of the compressor discharge system (valves 278, 282, 286), valves of the air flow delivery system (valves 312, 316, 320) and valves of the fuel delivery system 146 (diverter 274, valves 151A, 151B, 151C), as well as sensors 330 and fuel cell sensors 302 of the gas turbine engine 100), an aircraft incorporating the gas turbine engine 100, and the like.

[0135] The network interface 332E may include any suitable components for interfacing with one or more networks, including, for example, transmitters, receivers, ports, controllers, antennas, and / or other suitable components. In this manner, it will be understood that the network interface 332E may utilize any suitable combination of wired and wireless communication networks.

[0136] The technology discussed herein is with reference to computer-based systems, actions taken by computer-based systems, and information sent to and from computer-based systems. It will be appreciated that the inherent flexibility of computer-based systems allows for a variety of possible configurations, combinations, and divisions of tasks and functionality between and within components. For example, the processing discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memories, instructions, and applications can be implemented on a single system or distributed across multiple systems. Distributed components can operate sequentially or in parallel.

[0137] As briefly described above, the fuel cell assembly 204 may be in electrical communication with the electrical bus 326, which may be the electrical bus of the gas turbine engine 100, the electrical bus of the aircraft, or a combination thereof. Figure 5 , provides a schematic diagram of an aircraft 400 according to an embodiment of the present disclosure, the aircraft 400 including one or more gas turbine engines 100 (labeled 100A and 100B), each engine having an integrated fuel cell and combustor assembly 200 (labeled 200A and 200B), and an aircraft electrical bus 326 electrically connected to the one or more gas turbine engines 100.

[0138] For the exemplary embodiment depicted, aircraft 400 includes a fuselage 402, an empennage 404, a first wing 406, a second wing 408, and a propulsion system. The propulsion system generally includes a first gas turbine engine 100A coupled to or integrated with first wing 406 and a second gas turbine engine 100B coupled to or integrated with second wing 408. However, it will be appreciated that in other embodiments, any other suitable number and / or configuration of gas turbine engines 100 may be provided (e.g., mounted on the fuselage, mounted on the empennage, etc.).

[0139] The first gas turbine engine 100A generally includes a first integrated fuel cell and combustor assembly 200A and a first electric machine 410A. The first integrated fuel cell and combustor assembly 200A generally includes a first fuel cell assembly. The first electric machine 410A can be an embedded electric machine, an offset electric machine (e.g., capable of rotating with the gas turbine engine 100 via an accessory gearbox or a suitable gear train), or the like. For example, in certain exemplary embodiments, the first electric machine 410A can be a starter motor / generator for the first gas turbine engine 100A.

[0140] Similarly, the second gas turbine engine 100B generally includes a second integrated fuel cell and combustor assembly 200B and a second electric machine 410B. The second integrated fuel cell and combustor assembly 200B generally includes a second fuel cell assembly. The second electric machine 410B may also be an embedded electric machine, an offset electric machine (e.g., capable of rotating with the gas turbine engine 100 via an accessory gearbox or a suitable gear train), etc. For example, in certain exemplary embodiments, the second electric machine 410B may be a starter motor / generator for the second gas turbine engine 100B.

[0141] exist Figure 5 In the embodiment of FIG4 , aircraft 400 additionally includes electrical bus 326 and supervisory controller 412. Furthermore, it will be understood that aircraft 400 and / or propulsion system includes one or more electrical devices 414 and electrical energy storage unit 416, each in electrical communication with electrical bus 326. Electrical devices 414 may represent one or more aircraft power loads (e.g., avionics systems, control systems, electric propulsion, etc.), one or more power sources (e.g., auxiliary power units), etc. Electrical energy storage unit 416 may be, for example, a battery pack for storing electrical power.

[0142] The electrical bus 326 is further electrically connected to the first motor 410A and the first fuel cell assembly, and to the second motor 410B and the second fuel cell assembly. Figure 4 The controller 240 is similarly configured or may be in operative communication with a first gas turbine engine controller dedicated to the first gas turbine engine 100A and a second gas turbine engine controller dedicated to the second gas turbine engine 100B.

[0143] In this manner, it will be understood that the supervisory controller 412 can be configured to receive data from the gas turbine engine sensor 330A of the first gas turbine engine 100A and the gas turbine engine sensor 330B from the second gas turbine engine 100B, and can be further configured to send data (e.g., commands) to various control elements (such as valves) of the first and second gas turbine engines 100A, 100B.

[0144] Furthermore, it will be understood that for the depicted embodiment, aircraft 400 includes one or more aircraft sensors 418 configured to sense data indicative of various flight operations of aircraft 400 , including, for example, altitude, ambient temperature, ambient pressure, air velocity, etc. Supervisory controller 412 is operatively connected to these aircraft sensors 418 to receive data therefrom.

[0145] In addition to receiving data from the sensors 330A, 330B, 418 and sending data to the control elements, the supervisory controller 412 is also configured to control the flow of power through the electrical bus 326. For example, the supervisory controller 412 can be configured to command and receive a desired power draw from one or more motors (e.g., the first motor 410A and the second motor 410B), one or more fuel cell assemblies (e.g., the first fuel cell assembly and the second fuel cell assembly), or both, and provide all or a portion of the drawn power to the other of the one or more motors (e.g., the first motor 410A and the second motor 410B), one or more fuel cell assemblies (e.g., the first fuel cell assembly and the second fuel cell assembly), or both. One or more of these actions can be performed according to the logic outlined below.

[0146] refer to Figure 6 and 7 , an integrated fuel cell and combustor assembly 200 according to two exemplary embodiments of the present disclosure will be described.

[0147] First, special reference Figure 6 The plurality of fuel cell stacks 232 extend around the outer liner 210 defining the combustion chamber 228 or are integrated into the outer liner 210 defining the combustion chamber 228. The plurality of fuel cell stacks 232 are distributed along the axial direction A and independently receive air 244 from the air processing unit 306 and fuel 246 from the fuel processing unit 304.

[0148] exist Figure 6 In the embodiment, a first fuel cell stack 232A among the plurality of fuel cell stacks 232 is connected to the air processing unit 306 through a first air line including a valve, and is connected to the fuel processing unit 304 through a first fuel line including a valve; a second fuel cell stack 232B among the plurality of fuel cell stacks 232 is connected to the air processing unit 306 through a second air line including a valve, and is connected to the fuel processing unit 304 through a second fuel line including a valve; a third fuel cell stack 232C among the plurality of fuel cell stacks 232 is connected to the air processing unit 306 through a third air line including a valve, and is connected to the fuel processing unit 304 through a third fuel line including a valve; a fourth fuel cell stack 232D among the plurality of fuel cell stacks 232 is connected to the air processing unit 306 through a fourth air line including a valve, and is connected to the fuel processing unit 304 through a fourth fuel line including a valve; and a fifth fuel cell stack 232E among the plurality of fuel cell stacks 232 is connected to the air processing unit 306 through a fifth air line including a valve, and is connected to the fuel processing unit 304 through a fifth fuel line including a valve. In this embodiment, the various air lines, fuel lines, and valves are not labeled for clarity.

[0149] Because the fuel and air flows (e.g., flow rates) to the fuel cell stacks 232A, 232B, 232C, 232D, 232E are independently controllable (e.g., by a controller 240, not shown, which may be operably coupled to the respective valves), the output products 248 (e.g., from the fuel cell stacks 232A, 232B, 232C, 232D, 232E) along the axial length of the combustor 206 are controlled independently. Figure 6 The fuel cell stacks 232A, 232B, 232C, 232D, and 232E may be independently controllable to control the volume and composition (e.g., % H2) of the output products 248 within the combustion chamber 228 along the axial length of the combustor 206 to affect the axial temperature distribution therein, thereby reducing emissions through a "late lean" combustion approach.

[0150] The plurality of axially distributed fuel stacks 232 are configured to achieve at least one of late lean injection and a desired combustor gas concentration distribution. For example, the gas concentration distribution may be in the axial direction, in the circumferential direction, or a combination of both.

[0151] The controlled gas composition profile may include emission indicators including CO, carbon dioxide (CO2), water vapor (H2O), unburned hydrocarbons (UHC), particulate matter (e.g., primarily carbon), NO x and excess of at least one of atmospheric oxygen and nitrogen.

[0152] It will be appreciated that in the depicted embodiment, each of the fuel cell stacks 232A, 232B, 232C, 232D, 232E is configured to receive an air flow from the same air processing unit 306 and a fuel flow from the same fuel processing unit 304. However, in alternative exemplary embodiments, the illustrated fuel cell system may include more than one air processing unit 306, more than one fuel processing unit 304, or both. In this exemplary embodiment, the fuel cell system can be configured to provide air flow to one of the fuel cell stacks 232A, 232B, 232C, 232D, 232E at a higher or lower temperature, pressure, flow rate, or a combination thereof than the other fuel cell stacks 232A, 232B, 232C, 232D, 232E; and can be configured to provide fuel flow to one of the fuel cell stacks 232A, 232B, 232C, 232D, 232E at a higher or lower temperature, pressure, flow rate, or a combination thereof than the other fuel cell stacks 232A, 232B, 232C, 232D, 232E. This can facilitate a greater degree of control over the axial temperature distribution through the combustion chamber 228.

[0153] Although spacing is provided between the fuel cell stacks 232A, 232B, 232C, 232D, 232E for purposes of illustration, the fuel cell stacks 232A, 232B, 232C, 232D, 232E may completely cover the liner of the combustion chamber 228 along the length of the combustor 206 in the axial direction A.

[0154] In alternative embodiments described in more detail below, different fuel cell stacks 232 may extend along different lengths in the axial direction A. In some embodiments, the fuel cell stack 232 partially covers the liners 208 , 210 defining the combustion chamber 228 along the length of the combustor 206 in the axial direction A.

[0155] In alternative embodiments described in more detail below, different fuel cell stacks 232 may have different sizes (represented by height in the radial direction R). Here, the size of the fuel cell stack 232 generally corresponds to the maximum potential for generating electrical power for a given number of individual fuel cells and fuel cell stacks, and the maximum potential flow rate of the output products 248 therethrough to the combustion chamber 228.

[0156] Still refer to Figure 6 , the depicted exemplary fuel cell system further includes a plurality of fuel cell stacks 234A, 234B, 234C, 234D, 234E.

[0157] However, here, a plurality of fuel cell stacks 234A, 234B, 234C, 234D, 234E extend around the outer shell 220 of the combustor 206 or are integrated into the liner 208 of the combustor 206. The plurality of fuel cell stacks 234A, 234B, 234C, 234D, 234E are distributed along the axial direction A and are connected one after another in a cascade arrangement (e.g., a serial flow arrangement) by connectors 440, 442, 444, 446. Here, one fuel cell stack 234 ( Figure 6 The fuel 246 ( Figure 3 )(and / or air 244 from air handling unit 306 ( Figure 3 )) is configured to be provided to another fuel cell stack 234 ( Figure 6 The remaining fuel cell stacks 234B, 234C, 234D, 234E in the embodiment).

[0158] The connectors can be configured to control flow from one fuel cell stack 232 to the next. For example, the size of the grooves in each of the connectors 440, 442, 444, 446 can be reduced to reduce the amount of flow through the grooves. Additionally, the connectors 440, 442, 444, 446 can include valves that are configured to be controlled to control flow from one fuel cell stack 232 to the next.

[0159] exist Figure 6 In the figure, the first fuel cell stack 234A is connected to the fuel processing unit 304 through the first fuel flow pipeline 448; the second fuel cell stack 234B is connected to the first fuel cell stack 234A through the connector 440; the third fuel cell stack 234C is connected to the second fuel cell stack 234B through the connector 442; the fourth fuel cell stack 234D is connected to the third fuel cell stack 234C through the connector 444; and the fifth fuel cell stack 234E is connected to the fourth fuel cell stack 234D through the connector 446.

[0160] For example, fuel cell stack 234 (see also Figure 3 ) of the groove 247 ( Figure 3 ) can be connected through connectors 440, 442, 444, and 446.

[0161] Although not depicted, it will be understood that in at least certain exemplary embodiments, the fuel cell system may be similarly configured to provide air flow to the plurality of fuel cell stacks 234A, 234B, 234C, 234D, 234E in a similar cascaded manner.

[0162] It will be appreciated that this configuration provides for the output products 248 ( ) from the plurality of fuel cell stacks 234A, 234B, 234C, 234D, 234E to be aligned along the length of the combustor 206 in the axial direction A. Figure 3 ) control and distribution.

[0163] Now special reference Figure 7 , a plurality of fuel cell stacks 232A, 232B extend around the outer liner 210 defining the combustion chamber 228 or are integrated into the outer liner 210 defining the combustion chamber 228. The plurality of fuel cell stacks 232 are distributed along the axial direction A and independently receive air 244 ( Figure 3 ) and fuel 246 ( Figure 3 ).

[0164] exist Figure 7In an exemplary embodiment, a first fuel cell stack 232A among the plurality of fuel cell stacks 232 is connected to the air processing unit 306 via a first air flow line 500 including a valve 502, and is connected to the fuel processing unit 304 via a first fuel flow line 504 including a valve 506; and a second fuel cell stack 232B among the plurality of fuel cell stacks 232 is connected to the air processing unit 306 via a second air flow line 510 including a valve 512, and is connected to the fuel processing unit 304 via a second fuel flow line 514 including a valve 516.

[0165] Here, the first fuel cell stack 232A covers a greater length of the outer liner 210 defining the combustion chamber 228 in the axial direction A than the second fuel cell stack 232B. More specifically, the first fuel cell stack 232A has a greater length in the axial direction A than the second fuel cell stack 232B.

[0166] For example, the length of the first fuel cell stack 232A along the axial direction A can be at least about 5% larger than the length of the second fuel cell stack 232B along the axial direction A, such as at least about 10% larger, such as at least about 20% larger, such as at least about 25% larger, such as at least about 40% larger, such as at least about 60% larger, such as up to about 1,000% larger.

[0167] Furthermore, for the depicted embodiment, the first fuel cell stack 232A is upstream of the second fuel cell stack 232B, and the second fuel cell stack 232B is positioned at, adjacent to, proximate to, near, or the like, the downstream end 526 of the combustion chamber 228 in the axial direction A (i.e., the most downstream location of the combustion chamber 228 in the axial direction A). For example, the upstream end of the second fuel cell stack 232B is spaced a distance 522 from the upstream end 520 of the combustion chamber 228 (i.e., the most upstream location of the combustion chamber 228 in the axial direction A, e.g., at the dome 212 or the opening 229). The second fuel cell stack 232B provides the output products 248 to the combustion chamber 228 downstream of the distance 522 (e.g., at the downstream section 524 of the combustion chamber 228 or adjacent to the downstream end 526). The length 528 of the combustion chamber 228 in the axial direction A can be measured between the upstream end 520 and the downstream end 526.

[0168] Because the fuel and air flows (e.g., flow rates) to the fuel cell stacks 232A, 232B are independently controlled by the controller 240, the output products 248A, 248B from the respective fuel cell stacks 232A, 232B along the length 528 of the combustor 206 can be controlled to achieve an axial temperature distribution to reduce emissions through, for example, a "late lean" combustion approach.

[0169] For example, the controller 240 can increase the fuel flow rate to the second fuel cell stack 232B relative to the fuel flow rate to the first fuel cell stack 232A (e.g., represented by the longer output product 248 "arrow") to modify the composition of the output product 248, for example, to increase the % H2 in the output product, resulting in an increase in downstream secondary combustion in the combustion chamber. This distribution or composition of the output product 248 can provide more complete combustion of the combustion gases generated within the combustion chamber 228 and reduce certain emissions (such as NO x ) reduction.

[0170] Additionally or alternatively, the controller 240 can control one or both of the power converters 238, 239 to increase the current drawn from the second fuel cell stack 232B. By increasing the current in the downstream fuel cell stack 232B, the fuel cell exhaust gas injected downstream into the combustor 206 tends to have less residual fuel than the fuel cell exhaust gas injected upstream into the combustor 206. Given the same amount of air flow rate to both the first and second fuel cell stacks 232A, 232B, this approach produces a higher air / fuel ratio (or lean burn) at the downstream end of the combustor 206.

[0171] The controller 240 is configured to control the valves 506 , 516 in cooperation with the power converters 238 , 239 to achieve a desired combustor gas composition profile.

[0172] The controller 240 is configured to cooperatively control the valves 506 , 516 to achieve a desired combustor gas temperature profile.

[0173] The controller 240 is configured to cooperatively control the valves 506 , 516 to achieve a desired combustor gas pressure profile.

[0174] Additionally or alternatively, the temperature of the output products 248B from the second fuel cell stack 232B may be increased to provide a desired effect on the emissions within the combustion gases generated within the combustion chamber 228. For example, a higher temperature gas stream may be provided to the second fuel cell stack 232B to increase the temperature of the output products 248B therefrom.

[0175] It will be understood that, as discussed above with respect to Figure 6 As stated, despite Figure 7 Each of the fuel cell stacks 232A, 232B depicted in the drawings is constructed to receive an air flow from the same air processing unit 306 and a fuel flow through the same fuel processing unit 304, but in alternative exemplary embodiments, the fuel cell system shown may include more than one air processing unit 306, more than one fuel processing unit 304, or both.

[0176] Furthermore, it will be understood that although Figure 7 In some exemplary embodiments, the first fuel cell stack 232A (upstream fuel cell stack) has a longer axial dimension than the second fuel cell stack 232B (downstream fuel cell stack), but in other exemplary embodiments, this configuration can be reversed such that the downstream fuel cell stack has a longer axial dimension than the upstream fuel cell stack.

[0177] The distance 522 to the downstream section 524 can be at least 30% of the length 528 of the combustion chamber 228. For example, in certain exemplary embodiments, the distance 522 can be greater than or equal to half of the length 528 of the combustion chamber 228 in the axial direction A. For example, the distance 522 to the downstream section 524 can be at least two-thirds, at least three-fifths, or at least four-sevenths of the length 528 of the combustion chamber 228 in the axial direction A. This configuration can ensure that the second fuel cell stack 232B is positioned to provide a desired amount of secondary downstream combustion / heat addition to the combustion gases within the combustion chamber 228 to affect the generation of undesirable components (such as NO) in the combustion gases. x ) amount.

[0178] Now refer to Figure 8 , an integrated fuel cell and combustor assembly 200 according to an additional exemplary embodiment of the present disclosure will be described.

[0179] Figure 8 The exemplary integrated fuel cell and burner assembly 200 may be used with Figure 7 The exemplary integrated fuel cell and burner assembly 200 is constructed in a similar manner. For example, Figure 8 The exemplary integrated fuel cell and combustor assembly 200 includes a fuel cell stack 232 that extends around or is integrated into an outer liner 210 that defines a combustion chamber 228. The fuel cell stack 232 can receive air 244 from an air processing unit 306 and fuel from a fuel processing unit 304 ( Figure 8 246 of fuel (not shown).

[0180] Fuel cell stack 232 is positioned at, adjacent to, proximate to, near, etc., a downstream end 526 of combustion chamber 228 in axial direction A. The upstream end of fuel cell stack 232 is spaced a distance 522 from upstream end 520 of combustion chamber 228 (eg, dome 212 or opening 229 ).

[0181] Here, the fuel cell stack 232 is the frontmost fuel cell stack 232 .

[0182] In this embodiment, distance 522 represents the distance between an upstream location (e.g., upstream end 520 in the depicted embodiment) at which fuel is first provided to the combustion chamber 228 through opening 229 and a downstream location (e.g., upstream end 520 in the depicted embodiment) at which fuel or output products are next provided to the combustion chamber 228. The fuel cell stack 232 provides output products 248 to the combustion chamber 228 downstream of distance 522 (e.g., at a downstream section 524 of the combustion chamber 228 or adjacent to a downstream end 526). A length 528 of the combustion chamber 228 can be measured in the axial direction A between the upstream end 520 and the downstream end 526.

[0183] The distance 522 may be similar to the above with respect to Figure 7 For example, the distance 522 to the downstream section 524 may be at least 30% of the length 528 of the combustion chamber 228. In certain exemplary embodiments, the distance 522 may be greater than or equal to half of the length 528 of the combustion chamber 228 in the axial direction A. For example, the distance 522 to the downstream section 524 may be at least two-thirds, at least three-fifths, or at least four-sevenths of the length 528 of the combustion chamber 228 in the axial direction A.

[0184] The distance 522 to the downstream section 524 may be greater than or equal to half the length 528 of the combustion chamber 228 in the axial direction A. For example, the distance 522 to the downstream section 524 may be two-thirds, three-fifths, four-sevenths, etc., of the length 528 of the combustion chamber 228 in the axial direction A.

[0185] The output products 248 from the fuel cell stack 232 along a portion of the length of the combustor 206 in the axial direction A can be used to achieve a desired axial temperature distribution, particularly within the downstream section 524. This configuration can reduce emissions through a "late lean" combustion approach. For example, with less than 100% fuel utilization within the fuel cell stack 232, the output products 248 will include hydrogen (H2), which can promote secondary downstream combustion within the combustion chamber 228, potentially providing more complete combustion of the combustion gases flowing therethrough.

[0186] Additionally, it will be appreciated that the output products 248 may be provided to the combustion chamber 228 at a relatively high temperature and may further include oxygen. The high temperature of the output products 248 and the oxygen content of the output products 248 may similarly promote more complete combustion of the combustion gases flowing through the combustion chamber 228. The above effects may potentially reduce the release of undesirable components (e.g., NO) from the combustion gases from the combustion chamber. x ).

[0187] In certain exemplary embodiments, the controller 240 can modify the fuel flow rate to the fuel cell stack 232, the air flow rate to the fuel cell stack 232, the temperature of the air provided to the fuel cell stack 232, the current drawn from the fuel cell stack 232, or a combination thereof to modify the composition, temperature, flow rate, or a combination thereof of the output product 248 provided to the combustion chamber 228, thereby, for example, promoting more complete combustion of the combustion gases within the combustion chamber 228 near or within the downstream section 524 of the combustion chamber 228.

[0188] According to the exemplary method, a flow of aviation fuel is provided to the combustion chamber 228 of the combustor 206 through an opening 229 defined at an upstream end 520 of the combustion chamber 228 to initiate initial combustion within the combustion chamber 228. Additionally, an output product flow 248 is provided from the fuel cell stack 232 to the combustion chamber 228 at a downstream section 524 of the combustion chamber 228 to initiate secondary combustion within the combustion chamber 228 at a location downstream of the initial combustion within the combustion chamber 228.

[0189] Now refer to Figure 9 , an integrated fuel cell and combustor assembly 200 according to an additional exemplary embodiment of the present disclosure will be described.

[0190] Figure 9 The exemplary integrated fuel cell and burner assembly 200 may be used with Figure 7 The exemplary integrated fuel cell and burner assembly 200 is constructed in a similar manner. For example, Figure 9 The exemplary integrated fuel cell and combustor assembly 200 includes a fuel cell stack 232 that extends around or is integrated into an outer liner 210 that defines a combustion chamber 228. The fuel cell stack 232 can receive air 244 from an air processing unit 306 and fuel from a fuel processing unit 304 ( Figure 9 246 of fuel (not shown).

[0191] Figure 9 The fuel cell stack 232 includes a first fuel cell stack 232A and a second fuel cell stack 232B. The first fuel cell stack 232A is positioned at, adjacent to, proximate to, near, etc., an upstream end 520 of the combustion chamber 228 in the axial direction A, and the second fuel cell stack 232B is positioned at, adjacent to, proximate to, near, etc., a downstream end 526 of the combustion chamber 228 in the axial direction A. The upstream end of the second fuel cell stack 232B is spaced a distance 522 from the upstream end 520 of the combustion chamber 228 (e.g., the dome 212 or the opening 229).

[0192] The first fuel cell stack 232A provides output products 248A to the combustion chamber 228 upstream of the distance 522, and the second fuel cell stack 232B provides output products 248B to the combustion chamber 228 downstream of the distance 522 (e.g., at a downstream section 524 or adjacent to a downstream end 526 of the combustion chamber 228). The length 528 of the combustion chamber 228 may be measured between the upstream end 520 and the downstream end 526.

[0193] Furthermore, the dimensions of the second fuel cell stack 232B (e.g., height 550 in the radial direction R) are greater than the dimensions of the first fuel cell stack 232A (e.g., height 552 in the radial direction R). For example, the height 550 is 1.1 to 2 times greater than the height 552. In certain embodiments, the greater height in the radial direction can be achieved by stacking the fuel cells end-to-end in the radial direction R or by simply using longer fuel cells.

[0194] The greater height can allow the second fuel cell stack 232B to generate more electricity for a given number of fuel cells. Additionally or alternatively, the greater height can allow the second fuel cell stack 232B to provide output products 248B to the combustion chamber 228 near the downstream end 526 in a manner that better promotes more complete combustion and, therefore, fewer emissions.

[0195] For example, the controller 240 controls the power converter 236 ( Figure 2 ) to increase or decrease the current (I) drawn from the second fuel cell stack 232B, and control the valve to control the amount of fuel and the amount, pressure and temperature of air provided to the second fuel cell stack 232B, thereby controlling aspects of the output product 248B provided at the downstream section 524 of the combustion chamber 228.

[0196] In at least some exemplary aspects, the increase in the current (I) drawn by the power converter 236 can result in more hydrogen being consumed in the second fuel cell stack 232B (e.g., converted to electricity) and less fuel being discharged from the second fuel cell stack 232B into the combustion chamber 228. As a result, the second fuel cell stack 232B can provide less combustible gas to the combustion chamber 228, which can act as a vaporizer to reduce nitrogen oxides (NO x ). The stream with less combustible gas can be called high purity stream. High purity stream quenches NO x Reaction. NO x Decreases exponentially with increasing water or steam injection or increasing specific humidity.

[0197] Furthermore, providing the output product at the downstream section 524 (late lean) reduces the residence time of the output product and thus reduces NO x .

[0198] In other exemplary aspects, for a desired total heat input to the integrated fuel cell and burner assembly 200, heat may be supplied to the burner 206 ( Figure 4 ) provides less aircraft fuel. With this configuration, for a given air and fuel flow, less current can be drawn from the second fuel cell stack 232B, so that the output product 248B provided near the downstream end 526 contains a higher amount of combustible gas, such as H2, allowing for a lower peak temperature within the combustion chamber 228 and, therefore, resulting in less NO x form.

[0199] This written description uses examples to disclose the present disclosure, including the best mode, and to enable any person skilled in the art to practice the present disclosure, including making and using any device or system and performing any combined methods. The patentable scope of the present disclosure is defined by the claims and may include other examples that occur to those skilled in the art. If these other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims, then these other examples are intended to fall within the scope of the claims.

[0200] Further aspects are provided by the subject matter of the following clauses:

[0201] A propulsion system for an aircraft, the aircraft including an aircraft fuel supply, the propulsion system comprising: a turbine defining an axial direction and comprising a compressor section, a combustor and a turbine section arranged in a serial flow order, the combustor defining a combustion chamber and an opening at an upstream end of the combustion chamber, the combustor being configured to receive an aviation fuel flow from the aircraft fuel supply through the opening; and a plurality of fuel cell stacks extending around the combustion chamber, each of the plurality of fuel cell stacks being configured to provide an output product to the combustion chamber to achieve at least one of late lean injection and a desired combustor gas concentration distribution, the plurality of fuel cell stacks being distributed along the length of the combustion chamber in the axial direction.

[0202] The propulsion system of one or more of these clauses, wherein the combustor includes an outer liner at least partially defining the combustion chamber, wherein the plurality of fuel cell stacks extend around or are integrated into the outer liner.

[0203] The propulsion system of one or more of these clauses, wherein the combustor includes a liner at least partially defining the combustion chamber, wherein the plurality of fuel cell stacks extend around or are integrated into the liner.

[0204] The propulsion system of one or more of these clauses, wherein the plurality of fuel cell stacks have independent fuel inputs that are independently controlled.

[0205] The propulsion system according to one or more of these clauses, wherein the plurality of fuel cell stacks are connected one after the other in a serial flow arrangement.

[0206] The propulsion system of one or more of these clauses, wherein the plurality of fuel cell stacks includes a first fuel cell stack and a second fuel cell stack, wherein the second fuel cell stack is positioned upstream of the first fuel cell stack.

[0207] A propulsion system according to one or more of these clauses, wherein the first fuel cell stack includes first fuel cells defining a first height in a radial direction, wherein the second fuel cell stack includes second fuel cells defining a second height in the radial direction, and wherein the first height is greater than the second height.

[0208] The propulsion system of one or more of these clauses, wherein the first fuel cell stack defines a first length in the axial direction, wherein the second fuel cell stack defines a second length in the axial direction, and wherein the first length is different from the second length.

[0209] The propulsion system of one or more of these clauses, wherein the first fuel cell stack is configured to generate more electrical current from a fuel flow than the second fuel cell stack.

[0210] The propulsion system of one or more of these clauses further comprises a first fuel line extending to the first fuel cell stack; and a second fuel line extending to the second fuel cell stack, wherein the first fuel line and the second fuel line are configured to be independently controlled.

[0211] The propulsion system of one or more of these clauses, wherein the first fuel line comprises a first valve, and wherein the second fuel line comprises a second valve.

[0212] The propulsion system according to one or more of these clauses, further comprising a controller, wherein the controller is configured to control the first valve and the second valve independently or cooperatively to achieve a desired combustor gas composition distribution.

[0213] The propulsion system of one or more of these clauses, further comprising a controller, wherein the controller is configured to cooperatively control the first valve and the second valve using the first power converter and the second power converter to achieve a desired combustor gas composition distribution.

[0214] The propulsion system according to one or more of these clauses, wherein the controlled combustor gas composition distribution is in at least one of a combustor axial direction and a combustor circumferential direction.

[0215] A propulsion system according to one or more of these clauses, wherein the controlled combustor gas composition profile may include emission indicators including carbon monoxide, carbon dioxide, water vapor, unburned hydrocarbons, particulate matter, NOx, and excess atmospheric oxygen and nitrogen.

[0216] The propulsion system according to one or more of these clauses, further comprising a controller, wherein the controller is configured to control the first valve and the second valve independently or cooperatively to achieve a desired combustor gas temperature profile.

[0217] The propulsion system according to one or more of these clauses, wherein the controlled combustor gas temperature profile is in at least one of a combustor axial direction and a combustor circumferential direction.

[0218] The propulsion system according to one or more of these clauses, further comprising a controller, wherein the controller is configured to control the first valve and the second valve independently or cooperatively to achieve a desired combustor gas pressure profile.

[0219] The propulsion system according to one or more of these clauses, wherein the controlled combustor gas pressure distribution is in at least one of the axial direction and the circumferential direction of the combustor.

[0220] An assembly for late lean injection of fuel into a gas turbine combustor, comprising: a fuel and air premixing device configured to change a fuel composition; a fuel and air conditioning device configured to further change the fuel composition and generate electricity; and a controller configured to control the fuel and air premixing device and the fuel and air conditioning device to achieve a desired gas composition distribution in the combustor along an axial direction of the combustor.

Claims

1. A propulsion system for an aircraft, the aircraft comprising an aircraft fuel supply, characterized in that The propulsion system comprises: a turbomachine defining an axial direction and including a compressor section, a combustor, and a turbine section arranged in serial flow order, the combustor defining a combustion chamber and an opening at an upstream end of the combustion chamber, the combustor being configured to receive a flow of aviation fuel from the aircraft fuel supply through the opening; and a plurality of fuel cell stacks extending around the combustion chamber, each fuel cell stack in the plurality of fuel cell stacks being configured to provide output products to the combustion chamber to achieve at least one of late lean injection and a desired combustor gas concentration profile, the plurality of fuel cell stacks being distributed along a length of the combustion chamber in the axial direction; wherein the plurality of fuel cell stacks include a first fuel cell stack and a second fuel cell stack, wherein the second fuel cell stack is positioned upstream of the first fuel cell stack, wherein the first fuel cell stack includes a first fuel cell defining a first height in a radial direction, wherein the second fuel cell stack includes a second fuel cell defining a second height in the radial direction, and wherein the first height is greater than the second height.

2. The propulsion system according to claim 1, characterized in that The combustor includes an outer liner at least partially defining the combustion chamber, wherein the plurality of fuel cell stacks extend around or are integrated into the outer liner.

3. The propulsion system according to claim 1, characterized in that The combustor includes a liner at least partially defining the combustion chamber, wherein the plurality of fuel cell stacks extend around or are integrated into the liner.

4. The propulsion system according to claim 1, characterized in that The plurality of fuel cell stacks have independent fuel inputs that are independently controlled.

5. The propulsion system according to claim 1, characterized in that Wherein the plurality of fuel cell stacks are connected one after another in a serial flow arrangement.

6. The propulsion system according to claim 1, characterized in that wherein the first fuel cell stack defines a first length in the axial direction, wherein the second fuel cell stack defines a second length in the axial direction, and wherein the first length is different from the second length.

7. The propulsion system according to claim 1, characterized in that Wherein the first fuel cell stack is configured to generate more electrical current from a fuel flow than the second fuel cell stack.

8. The propulsion system according to claim 1, characterized in that Further include a first fuel line extending to the first fuel cell stack; and A second fuel line extends to the second fuel cell stack, wherein the first fuel line and the second fuel line are configured to be independently controlled.

9. The propulsion system according to claim 8, characterized in that Wherein the first fuel line includes a first valve, and wherein the second fuel line includes a second valve.

10. The propulsion system according to claim 9, characterized in that Further included is a controller, wherein the controller is configured to control the first valve and the second valve independently or cooperatively to achieve a controlled combustor gas composition profile.

11. The propulsion system according to claim 9, characterized in that A controller is further included, wherein the controller is configured to cooperatively control the first valve and the second valve using the first power converter and the second power converter to achieve a desired combustor gas composition distribution.

12. The propulsion system according to claim 10, characterized in that The controlled burner gas composition distribution is along at least one of the burner axial direction and the burner circumferential direction.

13. The propulsion system according to claim 10, wherein: The controlled burner gas composition profile may include emission indicators including carbon monoxide, carbon dioxide, water vapor, unburned hydrocarbons, NO x and excess atmospheric oxygen and nitrogen.

14. The propulsion system according to claim 9, wherein: Further included is a controller, wherein the controller is configured to control the first valve and the second valve independently or cooperatively to achieve a desired combustor gas temperature profile.

15. The propulsion system according to claim 10, wherein: The controlled burner gas temperature distribution is along at least one of the burner axial direction and the burner circumferential direction.

16. The propulsion system according to claim 9, wherein: Further included is a controller, wherein the controller is configured to control the first valve and the second valve independently or cooperatively to achieve a desired combustor gas pressure profile.

17. The propulsion system according to claim 10, wherein: Wherein the controlled burner gas pressure distribution is along at least one of the axial direction and the circumferential direction of the burner.

18. An assembly for late lean injection of fuel into a gas turbine combustor, characterized in that include: a fuel and air premixing device configured to change the fuel composition; a fuel and air conditioning device configured to further alter the fuel composition and generate electricity, the fuel and air conditioning device comprising a plurality of fuel cell stacks extending around the combustion chamber, wherein the plurality of fuel cell stacks comprises a first fuel cell stack and a second fuel cell stack, wherein the second fuel cell stack is positioned upstream of the first fuel cell stack, wherein the first fuel cell stack comprises first fuel cells defining a first height in a radial direction, wherein the second fuel cell stack comprises second fuel cells defining a second height in the radial direction, and wherein the first height is greater than the second height; and A controller is configured to control the fuel and air premixing device and the fuel and air conditioning device to achieve a desired gas composition distribution in the combustor along an axial direction of the combustor.

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