Multi-fuel, fuel injection system for a turbine engine

An assembly is provided for a turbine engine with a flowpath. This turbine engine assembly includes a fuel injection system. The fuel injection system includes a first fuel injector and a second fuel injector. The fuel injection system is configured to provide the first fuel injector with first fuel and provide the second fuel injector with second fuel. The first fuel may be or include ammonia. The second fuel is different than the first fuel. The second fuel may be or include hydrogen gas. The first fuel injector is configured to direct the first fuel into the flowpath for combustion. The second fuel injector is configured to direct the second fuel into the flowpath for combustion.

BACKGROUND OF THE DISCLOSURE

1. Technical Field

This disclosure relates generally to a turbine engine and, more particularly, to a fuel system for the turbine engine.

2. Background Information

As government emissions standards tighten, interest in alternative fuels for gas turbine engines continues to grow. For example, ammonia may be used to fuel a gas turbine engine rather than a more traditional hydrocarbon fuel such as kerosene. However, compared to a traditional hydrocarbon fuel, ammonia fuel has narrower flammability limits and slower flame speeds. Ammonia fuel is therefore more difficult to combust/burn than traditional hydrocarbon fuels, particularly where the gas turbine engine is operating at a relatively low power setting such as during initial ignition/startup.

SUMMARY OF THE DISCLOSURE

According to an aspect of the present disclosure, an assembly is provided for a turbine engine with a flowpath. This turbine engine assembly includes a fuel injection system. The fuel injection system includes a first fuel injector and a second fuel injector. The fuel injection system is configured to provide the first fuel injector with first fuel. The fuel injection system is configured to provide the second fuel injector with second fuel. The first fuel is or includes ammonia. The second fuel is different than the first fuel. The second fuel is or includes hydrogen gas. The first fuel injector is configured to direct the first fuel into the flowpath for combustion. The second fuel injector is configured to direct the second fuel into the flowpath for combustion.

According to another aspect of the present disclosure, another assembly is provided for a turbine engine with a flowpath. This turbine engine assembly includes a fuel injection system. The fuel injection system includes a fuel source, a first fuel injector and a second fuel injector. The fuel injection system is configured to process supply fuel output from the fuel source to provide first fuel and second fuel. The second fuel has a different composition than the first fuel. The first fuel injector is configured to inject the first fuel into the flowpath for combustion. The second fuel injector is configured to inject the second fuel into the flowpath for combustion.

According to another aspect of the present disclosure, another assembly is provided for a turbine engine. This turbine engine assembly includes a combustor and a fuel injection system. The combustor includes a combustion chamber. The fuel injection system is configured to inject non-hydrocarbon fuel into a volume upstream of the combustion chamber for subsequent combustion within the combustion chamber.

According to still another aspect of the present disclosure, a method is provided for operating a turbine engine with a flowpath. During this method, ammonia is processed with a fuel injection system to provide first fuel and second fuel. The first fuel includes at least the ammonia. The second fuel includes at least hydrogen gas extracted from the ammonia. The first fuel is directed into the flowpath and the second fuel is separately directed into the flowpath. The first fuel and the second fuel are combusted within the flowpath.

The first fuel injector may be configured to direct a first mass flow of the first fuel into the flowpath. The second fuel injector may be configured to direct a second mass flow of the second fuel into the flowpath. The second mass flow of the second fuel may be different (e.g., less) than the first mass flow of the first fuel.

The first fuel injector may be configured to direct the first fuel into the flowpath for combustion when the turbine engine is in a first mode of operation. The second fuel injector may be configured to direct the second fuel into the flowpath for combustion when the turbine engine is in a second mode of operation.

The first fuel injector may not direct the first fuel into the flowpath when the turbine engine is in the second mode of operation.

The second fuel injector may be configured to direct the second fuel into the flowpath for combustion when the turbine engine is in the first mode of operation.

The second fuel injector may not direct the second fuel into the flowpath when the turbine engine is in the first mode of operation.

At least a majority of the first fuel may be the ammonia. In addition or alternatively, at least a majority of the second fuel may be the hydrogen gas.

The fuel injection system may also include a fuel reservoir, a first fuel circuit and a second fuel circuit. The first fuel circuit may fluidly couple the fuel reservoir with the first fuel injector. The second fuel circuit may fluidly couple the fuel reservoir with the second fuel injector.

The fuel reservoir may be configured to provide supply fuel to the first fuel circuit and the second fuel circuit. The supply fuel may be or include the ammonia. The first fuel circuit may be configured to flow the first fuel received from the fuel reservoir to the first fuel injector. The second fuel circuit may be configured to treat the supply fuel received from the fuel reservoir to provide the second fuel to the second fuel injector.

The fuel reservoir may be configured to provide supply fuel to the first fuel circuit and the second fuel circuit. The first fuel circuit may be configured to process the supply fuel received from the fuel reservoir to provide the first fuel to the first fuel injector. The second fuel circuit may be configured to process the supply fuel received from the fuel reservoir to provide the second fuel to the second fuel injector.

The processing of the supply fuel by the first fuel circuit and/or the second fuel circuit may be or otherwise include any one or more of the following: flowing the supply fuel; treating the supply fuel; separating components within the supply fuel; filtering the supply fuel; and/or otherwise processing the supply fuel.

The second fuel circuit may be configured to receive the ammonia from the fuel reservoir. The second fuel circuit may include a fuel treatment device configured to at least partially crack the ammonia to provide at least partially cracked fuel. The at least partially cracked fuel may be or include the second fuel.

The at least partially cracked fuel may also include a byproduct. The byproduct may be or include nitrogen gas and/or the ammonia. The second fuel circuit may include a fuel separation device configured to: (A) retain the second fuel within the second fuel circuit downstream of the fuel separation device for providing to the second fuel injector; and/or (B) at least partially remove the byproduct from the second fuel circuit.

The at least partially cracked fuel may also include a byproduct. The byproduct may be or include nitrogen gas and/or the ammonia. The second fuel circuit may include a fuel separation device configured to: (A) retain the second fuel within the second fuel circuit for providing to the second fuel injector; and/or (B) direct at least some of the byproduct out of the second fuel circuit and into the first fuel circuit.

The first fuel circuit may be configured to receive the ammonia from the fuel reservoir. The first fuel circuit may include a fuel treatment device configured to partially crack the ammonia to provide partially cracked fuel. The partially cracked fuel may include the ammonia, hydrogen gas and nitrogen gas.

The second fuel circuit may include a second fuel reservoir. The second fuel reservoir may be configured to contain a supply of the second fuel for provision to the second fuel injector.

The fuel injection system may also include a first reservoir and a second reservoir. The first reservoir may be configured to contain at least the first fuel. The first reservoir may be upstream of and fluidly coupled with the first fuel injector. The second reservoir may be configured to contain the second fuel. The second reservoir may be upstream of and fluidly coupled with the second fuel injector.

The assembly may also include a combustor with a combustion chamber. The flowpath may include the combustion chamber. The first fuel injector may be configured to direct the first fuel into the flowpath at an inlet to the combustion chamber. The second fuel injector may be configured to direct the second fuel into the flowpath at the inlet to the combustion chamber.

The assembly may also include a combustor with a combustion chamber. The flowpath may include the combustion chamber. The first fuel injector may be configured to direct the first fuel into the flowpath upstream of an inlet to the combustion chamber. The second fuel injector may be configured to direct the second fuel into the flowpath at the inlet to the combustion chamber.

The first fuel injector may be a main fuel injector. The combustion of the first fuel within the flowpath may provide a main flame. The second fuel injector may be a pilot fuel injector. The combustion of the second fuel within the flowpath may provide a pilot flame.

A ratio of the second mass flow of the second fuel to the first mass flow of the first fuel may be equal to or less than 1:9.

The fuel reservoir may be fluidly coupled with the first fuel circuit and the second fuel circuit in parallel.

The supply fuel may consist essentially of/only include the ammonia.

The first fuel may consist essentially of/only include the ammonia.

The first fuel may also include hydrogen gas and/or nitrogen gas.

The second fuel may consist essentially of/only include the hydrogen gas.

The second fuel may also include nitrogen gas.

The second fuel may also include the ammonia.

The fuel treatment device may be arranged upstream of and fluidly coupled with the second fuel injector.

The second fuel injector may be configured with or otherwise include the fuel treatment device.

The assembly may also include a swirler and a combustor with a combustion chamber. The flowpath may include the combustion chamber. The swirler may be configured to direct compressed air into the combustion chamber. The first fuel injector may be configured to direct the first fuel into the flowpath at the swirler. The second fuel injector may be configured to direct the second fuel into the flowpath at the swirler.

The assembly may also include a swirler and a combustor with a combustion chamber. The flowpath may include the combustion chamber. The swirler may be configured to direct compressed air into the combustion chamber. The first fuel injector may be configured to direct the first fuel into the flowpath upstream of the swirler. The second fuel injector may be configured to direct the second fuel into the flowpath at the swirler.

The assembly may also include a swirler and a combustor with a combustion chamber. The flowpath may include the combustion chamber. The swirler may be configured to direct swirled compressed air into the combustion chamber.

The first fuel injector may be configured to direct the first fuel into the flowpath at the swirler.

The first fuel injector may be configured to direct the first fuel into a portion of the flowpath upstream of the swirler.

The combustor may include a bulkhead and a cowl. The portion of the flowpath may be formed by and between the bulkhead and the cowl.

The assembly may also include a convector wall extending along at least a portion of a wall of the combustor. The portion of the flowpath may be formed by and between the convector wall and the wall of the combustor.

The portion of the flowpath may be upstream of the swirler.

The first fuel injector may be configured to direct the first fuel into a portion of the flowpath that is upstream of the combustion chamber and fluidly in parallel with a path through the swirler.

The assembly may also include a bleed duct configured to bleed air from a first portion of the flowpath and provide the bleed air to another structure of the turbine engine. The first fuel injector may be configured to direct the first fuel into a second portion of the flowpath that is upstream of the swirler and downstream of the first portion of the flowpath.

The non-hydrocarbon fuel may be or include ammonia.

The combustor may include a cowl and a bulkhead. The volume may be or include a plenum formed by and between the cowl and the bulkhead.

The volume may be or include a diffuser plenum. The combustor may be arranged within the diffuser plenum.

The assembly may also include a convector wall spaced from the combustor to provide a flow passage between the combustor and the convector wall. The flow passage may be fluidly coupled with and upstream of the combustion chamber. The volume may be or include the flow passage.

The assembly may include a compressor section. The volume may be or include a pre-diffuser passage that leads to a diffuser plenum adjacent the combustor. The compressor section may be configured to provide compressed air to the combustion chamber sequentially through the pre-diffuser passage and the diffuser plenum.

The fuel injection system may also be configured to inject second fuel into a flowpath of the turbine engine for combustion within the combustion chamber. The second fuel may be different than the non-hydrocarbon fuel. The flowpath may include the volume and the combustion chamber.

The non-hydrocarbon fuel and the second fuel may be sourced from a common fuel source.

The second fuel may be or include a second non-hydrocarbon fuel.

The second fuel may be or include a hydrocarbon fuel.

DETAILED DESCRIPTION

FIG.1is a schematic illustration of an assembly20for a turbine engine with at least one flowpath22; e.g., a core flowpath, a gas path, etc. This turbine engine assembly20includes a multi-fuel, fuel injection system24configured to selectively direct (e.g., inject) at least first fuel26and second fuel28into the flowpath22for combustion.

The flowpath22may include one or more (e.g., serially arranged) fluidly coupled passages, chambers, plenums and/or any other internal volumes that collectively form a pathway for fluid flow (e.g., gas flow) within the turbine engine. The flowpath22may extend within and/or through any one or more sections of the turbine engine. The flowpath22may include, for example: a passage within a compressor section of the turbine engine; a pre-diffuser passage, a diffuser plenum and/or a combustion chamber within a combustor section of the turbine engine; and a passage within a turbine section of the turbine engine. The flowpath22may also include a passage within a fan section of the turbine engine, a passage within an exhaust section of the turbine engine and/or a passage in a supplemental thrust section of the turbine engine. The present disclosure, however, is not limited to the foregoing exemplary flowpath configurations.

The first fuel26and the second fuel28may each be a non-hydrocarbon fuel (e.g., a hydrocarbon-free fuel) and/or a non-coking fuel. The first fuel26and the second fuel28, for example, may each be or may otherwise include: ammonia (NH3) and/or a fuel composition derivable from the ammonia. The first fuel26, however, is different from the second fuel28. More particularly, the first fuel26has a different chemical composition (e.g., includes one or more different components) than the second fuel28. The first fuel26and the second fuel28, however, may be sourced (e.g., received) from a common (the same) fuel source30as shown, for example, inFIG.1. Alternatively, the first fuel26and the second fuel28may be sourced from different fuel sources30A and30B (generally referred to as “30”) as shown, for example, inFIG.2(see alsoFIG.7.).

The first fuel26directed into the flowpath22for combustion may be (e.g., only include) ammonia; e.g., liquid and/or gaseous NH3. Alternatively, the first fuel26may include one or more additional fuel components. The first fuel26, for example, may also include nitrogen (e.g., liquid or gaseous N2) and/or hydrogen (e.g., liquid or gaseous H2). For example, the first fuel26may (e.g., at least, substantially or only) include the ammonia (e.g., gaseous NH3) and the nitrogen (e.g., gaseous N2). In another example, the first fuel26may (e.g., at least, substantially or only) include the ammonia (e.g., gaseous NH3), the nitrogen (e.g., gaseous N2) and the hydrogen (e.g., gaseous H2). However, a majority (e.g., more than fifty percent (50%)) of the first fuel26is typically the ammonia. For example, at least sixty percent (60%), seventy percent (70%), eighty percent (80%), ninety percent (90%) or more of the first fuel26may be the ammonia, where the remaining percentage/portion of the first fuel26is/are the additional fuel component(s); e.g., the nitrogen and/or the hydrogen. The present disclosure, however, is not limited to the foregoing exemplary first fuel compositions. For example, the first fuel26may be or may include any composition of fuel component(s) where a percentage of the ammonia (e.g., gaseous NH3) in the first fuel26is greater than a percentage of the ammonia (e.g., gaseous NH3) in the second fuel28.

The second fuel28directed into the flowpath22for combustion may be (e.g., only include) the hydrogen; e.g., liquid or gaseous H2. Alternatively, the second fuel28may include one or more additional fuel components. The second fuel28, for example, may also include nitrogen (e.g., liquid or gaseous N2) and/or ammonia (liquid and/or gaseous NH3). For example, the second fuel28may (e.g., at least, substantially or only) include the hydrogen (e.g., gaseous H2) and the nitrogen (e.g., gaseous N2). In another example, the second fuel28may (e.g., at least, substantially or only) include the hydrogen (e.g., gaseous H2), the nitrogen (e.g., gaseous N2) and the ammonia (gaseous NH3). However, a majority (e.g., more than fifty percent (50%)) of the second fuel28is typically the hydrogen. For example, at least sixty percent (60%), seventy percent (70%), eighty percent (80%), ninety percent (90%) or more of the second fuel28may be the hydrogen, where the remaining percentage/portion of the second fuel28is/are the additional fuel component(s); e.g., the nitrogen and/or the ammonia. The present disclosure, however, is not limited to the foregoing exemplary second fuel compositions. For example, the second fuel28may be or may include any composition of fuel component(s) where a percentage of the pure hydrogen (e.g., gaseous H2) in the second fuel28is greater than a percentage of the pure hydrogen (e.g., gaseous H2) in the first fuel26.

The fuel injection system24ofFIG.1includes a first fuel circuit32, a first fuel injector34, a second fuel circuit36and a second fuel injector38. The fuel injection system24ofFIG.1also includes the fuel source30.

The fuel source30is configured to provide supply fuel to the first fuel circuit32and/or the second fuel circuit36during turbine engine operation. The fuel source30may also be configured to store the supply fuel during turbine engine operation and/or while the turbine engine is non-operational; e.g., before and/or after turbine engine operation.

The supply fuel stored and/or provided by the fuel source30is a fuel which can be processed (e.g., delivered and/or treated) to provide the first fuel26and/or the second fuel28. The supply fuel, for example, may be a non-hydrocarbon fuel (e.g., hydrocarbon-free fuel) and/or a non-coking fuel. The supply fuel, more particularly, may be (e.g., only include) the ammonia; e.g., gaseous or liquid NH3. The present disclosure, however, is not limited to the foregoing exemplary supply fuel.

The fuel source30ofFIG.1includes a fuel reservoir40and a fuel regulator42. The fuel reservoir40may be configured as or otherwise include a container; e.g., a tank, a cylinder, a pressure vessel, a bladder, etc. The fuel reservoir40is configured to contain and hold a quantity of the supply fuel. The fuel regulator42may be configured as or otherwise include a pump and/or a valve. The fuel regulator42is configured to control flow of the supply fuel from the fuel reservoir40to one or more downstream components of the turbine engine. The fuel regulator42ofFIG.1, for example, directs (e.g., pumps) the supply fuel out from the fuel reservoir40to at least the first fuel circuit32and the second fuel circuit36.

Where the supply fuel is stored in the fuel reservoir40as liquid ammonia, the fuel source30may also include a fuel vaporizer44. This fuel vaporizer44ofFIG.1is configured to at least partially or completely vaporize the supply fuel directed out of the fuel reservoir40and supplied to the first fuel circuit32and/or the second fuel circuit36. The fuel vaporizer44, for example, may be configured as or otherwise include an electric heater and/or a fluid-to-fluid heat exchanger (e.g., a liquid-to-liquid heat exchanger or a gas-to-liquid heat exchanger). The fuel source30may thereby provide the supply fuel to the first fuel circuit32and/or the second fuel circuit36as gaseous ammonia. The fuel vaporizer44may be fluidly coupled (e.g., in serial) between the fuel reservoir40and the fuel regulator42. Alternatively, the fuel regulator42may be fluidly coupled (e.g., in serial) between the fuel reservoir40and the fuel vaporizer44. Of course, in other embodiments, one or more of the fuel circuits32,36may each also or alternatively include its own dedicated fuel vaporizer.

The first fuel circuit32is configured to process the supply fuel received from the fuel source30to provide the first fuel26. The first fuel circuit32is also configured to provide the first fuel26to the first fuel injector34. More particularly, the first fuel circuit32ofFIG.1is configured to direct (e.g., flow) the supply fuel (e.g., gaseous ammonia) from the fuel source30to the first fuel injector34. In this embodiment, the first fuel26is the same as the supply fuel; e.g., both the supply fuel and the first fuel26are or include the ammonia. However, the present disclosure is not limited thereto as described below in further detail.

The first fuel circuit32includes a first fuel circuit passage that fluidly couples the fuel source30with the downstream first fuel injector34. The first fuel circuit32and the first fuel circuit passage ofFIG.1, for example, extend between and are connected to the fuel source30and the first fuel injector34.

The first fuel circuit passage may be formed by an internal bore of/through at least one conduit; e.g., a pipe, a hose, a tube, etc. The first fuel circuit passage may also or alternatively be formed by an internal bore, an internal channel and/or an internal void within and/or through one or more other fuel devices and/or structures. Examples of such other fluid devices and/or structures include, but are not limited to, a fuel heater, a fuel cooler, a fluid-to-fluid heat exchanger, a fuel filter, a valve, a pump, an inline fuel reservoir, a sensor and/or a manifold.

The first fuel injector34is configured to receive the first fuel26from the first fuel circuit32. The first fuel injector34is also configured to direct (e.g., inject) the first fuel26into the flowpath22for subsequent combustion downstream within the flowpath22.

The second fuel circuit36is configured to process the supply fuel received from the fuel source30to provide the second fuel28. The second fuel circuit36is also configured to provide the second fuel28to the second fuel injector38. More particularly, the second fuel circuit36ofFIG.1is configured to treat the supply fuel and provide that treated supply fuel (now referred to as the second fuel28) to the second fuel injector38. This treatment of the supply fuel may at least partially or completely crack the supply fuel to provide at least partially cracked or completely cracked supply fuel—the second fuel28. For example, where the supply fuel received from the fuel source30is gaseous ammonia, the second fuel circuit36may partially crack that gaseous ammonia to provide a mixture of hydrogen (H2) gas, nitrogen (N2) gas and ammonia (NH3) gas. Alternatively, the second fuel circuit36may completely crack the gaseous ammonia to provide a mixture of the hydrogen gas and the nitrogen gas. In addition, the second fuel circuit36may separate the hydrogen gas from the nitrogen gas and any residual ammonia gas, to provide the second fuel28to injector38that is substantially hydrogen (H2) gas. The remaining nitrogen gas and ammonia gas, after separation from the hydrogen gas, can be returned to fuel source30or delivered to the first fuel circuit32; e.g., seeFIG.7.

The second fuel circuit36includes a second fuel circuit passage that fluidly couples the fuel source30with the downstream second fuel injector38. The second fuel circuit36and the second fuel circuit passage ofFIG.1, for example, extend between and are connected to the fuel source30and the second fuel injector38.

The second fuel circuit passage is formed by a pathway (or pathways) through a fuel treatment device46. This fuel treatment device46is configured to at least partially or completely crack the supply fuel to provide the second fuel28. The fuel treatment device46, for example, may be configured as or otherwise include a heater (e.g., an electric heater) and/or a fluid-to-fluid heat exchanger (e.g., a liquid-to-liquid heat exchanger, a gas-to-liquid heat exchanger or a gas-to-gas heat exchanger). The pathway through the fuel treatment device46may be at least partially (or completely) lined, coated and/or otherwise formed by at least one catalyst48, or partially filled with catalyst-containing material such as pellets or honeycomb. Examples of the catalyst48include, but are not limited to, nickel (Ni), iron (Fe), ruthenium (Ru) and platinum (Pt). The present disclosure, however, is not limited to the foregoing exemplary catalytic materials. The fuel treatment device46may also be configured to separate, after cracking, the hydrogen gas from the nitrogen gas and any residual ammonia gas; e.g., seeFIG.7.

The second fuel circuit passage is also formed by an internal bore of/through one or more conduits; e.g., pipes, hoses, tubes, etc. The second fuel circuit passage may also or alternatively be formed by an internal bore, an internal channel and/or an internal void within and/or through one or more other fuel devices and/or structures. Examples of such other fluid devices and/or structures include, but are not limited to, a fuel heater, a fuel cooler, a fluid-to-fluid heat exchanger, a fuel filter, a valve, a pump, an inline fuel reservoir, a sensor and/or a manifold.

The second fuel injector38is configured to receive the second fuel28from the second fuel circuit36. The second fuel injector38is also configured to direct (e.g., inject) the second fuel28into the flowpath22for subsequent combustion downstream within the flowpath22.

During operation of the turbine engine assembly20ofFIG.1, the fuel source30provides the supply fuel (e.g., ammonia gas) to the first fuel circuit32and the second fuel circuit36. The fuel source30ofFIG.1and its components40,42and44are connected in parallel with the first fuel circuit32and the second fuel circuit36. The first fuel circuit32and the second fuel circuit36may thereby each receive the supply fuel (e.g., NH3gas) from the fuel source30independent of the other respective circuit36,32.

The first fuel circuit32processes the supply fuel (e.g., NH3gas) received from the fuel source30to provide the first fuel26(e.g., NH3gas). More particularly, the first fuel circuit32ofFIG.1directs (e.g., flows) the supply fuel received from the fuel source30to the first fuel injector34as the first fuel26. The first fuel injector34directs (e.g., injects) the first fuel26(e.g., the supply fuel) received from the first fuel circuit32into the flowpath22for combustion within the flowpath22.

The second fuel circuit36processes the supply fuel (e.g., NH3gas) received from the fuel source30to provide the second fuel28(e.g., a mixture of H2gas, N2gas and NH3gas). More particularly, the second fuel circuit36ofFIG.1treats (e.g., at least partially or completely cracks) the supply fuel to provide that treated supply fuel (e.g., at least partially or completely cracked supply fuel)—the second fuel28—to the second fuel injector38. The second fuel injector38directs (e.g., injects) the second fuel28received from the second fuel circuit36into the flowpath22for combustion within the flowpath22.

By using a non-hydrocarbon fuel such as ammonia and/or components (H2gas and N2gas) derived therefrom, the turbine engine assembly20may operate without, for example, producing potentially harmful emissions such as, but not limited to, carbon dioxide (CO2) emissions and non-volatile particulate matter (nvPM) emissions (also referred to as “black carbon”). In addition, such a non-hydrocarbon fuel may be operable to absorb a significant quantity of heat without coking like a traditional hydrocarbon fuel such as kerosene (e.g., jet fuel). The supply fuel, the first fuel26and/or the second fuel28may thereby be utilized for cooling one or more other components of the turbine engine and/or one or more other paired systems such as, but not limited to, an aircraft cabin climate system. The fuel vaporizer44(e.g., heat exchanger) ofFIG.1, for example, may be fluidly coupled with another fluid system50; e.g., a lubrication system, a coolant system, another fuel system, a heating and/or cooling system, etc. Heated fluid (e.g., coolant, lubricant, air, etc.) from the other fluid system50may be directed through the fuel vaporizer44, where the fuel vaporizer44facilitates a transfer of heat energy from the heated fluid to the fuel (e.g., the liquid ammonia) thereby cooling the fluid for the other fluid system50. The heat absorption capability of ammonia may thereby be used to recapture waste heat energy and improve efficiency of the turbine engine in a manner generally not feasible with a traditional hydrocarbon engine. The present disclosure, of course, is not limited to the foregoing heat transfer arrangement. For example, in other embodiments, one or more heat exchangers52may also or alternatively be fluidly coupled between the fuel source30and a respective fuel circuit32,36, fluidly coupled inline within a respective one of the fuel circuits32,36, or otherwise arranged.

The high heat absorption potential of a non-hydrocarbon fuel such as ammonia may come from its high heat of vaporization (as it undergoes phase change from liquid to gas), its coke-free nature at high temperatures and/or its propensity to undergo endothermic cracking upon heating to form hydrogen gas and nitrogen gas. Thus, ammonia may be used as fuel in a gas turbine engine both in its pure form (NH3) and its cracked form (H2and N2).

A non-hydrocarbon fuel such as ammonia may have relatively narrow flammability limits and relatively slow flame speeds. Thus, ammonia fuel may be more difficult to combust/burn than a traditional hydrocarbon fuel. Ammonia fuel may therefore be mixed with (e.g., compressed) air at a higher temperature, pressure and/or concentration than a traditional hydrocarbon fuel without or with relatively low concern for ignition or flame propagation (including flashback) in an air-fuel mixing region prior to combustion within, for example, a combustion region56of the flowpath22; e.g., the combustion chamber57. Ammonia fuel may thereby be used to provide premixing with the (e.g., compressed) air prior to combustion. Such premixing may lower NOx emissions of the turbine engine. Premixing may also or alternatively provide control of combustion dynamics; e.g., control of combustion-induced pressure oscillations. Various premixing methodologies and techniques are discussed below in further detail.

Ammonia fuel, however, may have flame anchoring issues and/or flame stability issues given its lower flammability limits and flame speeds. This may be particularly true at low power conditions where combustor inlet temperatures are relatively low. Ammonia fuel may also or alternatively have slip issues (e.g., unburned ammonia may be present in the exhaust) when combustion efficiency is low (even if combustion is stable). This may be particularly true at low power conditions where combustor inlet temperatures and combustor outlet temperatures are relatively low.

When combusting a non-hydrocarbon fuel such as ammonia at low power conditions, there is a need to provide continuous, stable combustion (e.g., good flame holding) and/or relatively high combustion efficiency (e.g., low ammonia slip). Thus, the ammonia fuel may be paired with another fuel with higher flame speeds and/or wider flammability limits. The turbine engine assembly20ofFIG.1therefore includes both the first and the second fuel injectors34and38to provide a mixture of ammonia gas, hydrogen gas and nitrogen gas for combustion. More particularly, the second fuel injector38injects the second fuel28(e.g., at least hydrogen gas) for providing a relatively stable (e.g., pilot) flame within a (e.g., pilot) zone58(see alsoFIGS.3and4) of the combustion region56of the flowpath22. This second fuel flame may also increase the temperature within the combustion region56of the flowpath22. This second fuel flame within the (e.g., pilot) zone58may be utilized for igniting and/or sustaining ignition of the first fuel26injected by the first fuel injector34in another (e.g., main) zone60(see alsoFIGS.3and4) of the combustion region56of the flowpath22, where the flame in the (e.g., main) zone60is adjacent and in contact with (e.g., overlapping) the flame in the (e.g., pilot) zone58. The second fuel injector38is thereby operable as a pilot fuel injector for the (e.g., main) first fuel injector34.

Unlike pure ammonia (NH3), flame speeds and flammability limits of cracked ammonia (e.g., a mixture hydrogen gas and nitrogen gas with or without residual ammonia gas) can be relatively close to the flame speeds and flammability limits of a traditional hydrocarbon fuel, depending on the degree of cracking. Thus, premixing (e.g., completely) cracked ammonia with (e.g., compressed) air upstream of the combustion region56of the flowpath22(e.g., the combustion chamber57) may increase likelihood of flashback and/or flame holding in the pre-mixer. The turbine engine assembly20ofFIG.1thereby arranges the second fuel injector38downstream of the first fuel injector34. The first fuel injector34, for example, may be configured to direct the first fuel26into an upstream premix region62of the flowpath22(e.g., a diffuser plenum, a cowl plenum, etc.) whereas the second fuel injector38may be configured to direct the second fuel28into the downstream combustion region56of the flowpath22; e.g., the combustion chamber57. Optionally (or alternatively), the first fuel injector34may also be configured to inject the first fuel26directly into the combustion region56without premixing.

As discussed above, the first fuel injector34may be configured as a main fuel injector and the second fuel injector38may be configured as a pilot fuel injector. With such an arrangement, the first fuel injector34may be configured to inject a (e.g., maximum) first mass flow of the first fuel26into the flowpath22. The second fuel injector38may be configured to inject a (e.g., maximum) second mass flow of the second fuel28into the flowpath22. The second mass flow of the second fuel28may be different (e.g., less) than the first mass flow of the first fuel26. A ratio of the second mass flow of the second fuel28to the first mass flow of the first fuel26may be, for example, equal to or less than 1:8, 1:9 or 1:10. The present disclosure, however, is not limited to the foregoing exemplary fuel injection ratios.

The second fuel injector38may be configured such that its second mass flow of the second fuel28is sufficient to provide rapid, robust and/or near-complete combustion of the second fuel28within the (e.g., pilot) zone58before spreading into the (e.g., main) zone60. The (e.g., pilot) flame may thereby be independently stable and capable of igniting the first fuel26in the (e.g., main) zone60to provide the (e.g., main) flame. The (e.g., main) zone60may be located in a region of the flowpath22(e.g., the combustion chamber57) which includes aerodynamic back mixing to facilitate anchoring of the (e.g., main) flame. The (e.g., pilot) flame therefore may be relatively small; e.g., where the ratio of the second mass flow to the first mass flow is equal to or less than 1:8, 1:9 or 1:10 as described above. The back mixing may be facilitated by configuring the second fuel injector38with a bluff body, a backwards facing step and/or providing a vortex breakdown of swirling inflow. Examples of such configurations are substantially shown inFIGS.3and4.

Referring again toFIG.1, the first fuel injector34and the second fuel injector38may be configured to operate concurrently in some modes of operation. The first fuel injector34and the second fuel injector38may also or alternatively be configured to operate discretely in other mode of operation. For example, referring toFIG.5, the turbine engine system may include a valve system64configured to selectively regulate the supply fuel to the first fuel circuit32and/or the second fuel circuit36. The valve system64ofFIG.5, for example, includes a first valve66and a second valve68.

The first valve66is fluidly coupled (e.g., serially) inline between the fuel source30and the first fuel circuit32. This first valve66may be configurable in a (e.g., fully) open position and a (e.g., fully) closed position. In the open position, the supply fuel may flow from the fuel source30to the first fuel circuit32unimpeded. In the closed position, the first valve66may prevent any flow of the supply fuel from the fuel source30to the first fuel circuit32. Of course, in other embodiments, the first valve66may be configured to operate in one or more intermediate (e.g., partially) open positions so as to permit a limited flow of the supply fuel from the fuel source30to the first fuel circuit32.

The second valve68is fluidly coupled (e.g., serially) inline between the fuel source30and the second fuel circuit36. This second valve68may be configurable in a (e.g., fully) open position and a (e.g., fully) closed position. In the open position, the supply fuel may flow from the fuel source30to the second fuel circuit36unimpeded. In the closed position, the second valve68may prevent any flow of the supply fuel from the fuel source30to the second fuel circuit36. Of course, in other embodiments, the second valve68may be configured to operate in one or more intermediate (e.g., partially) open positions so as to permit a limited flow of the supply fuel from the fuel source30to the second fuel circuit36.

In a first mode of operation during, for example, low engine power operation (e.g., engine ignition, engine startup, engine shutdown, engine idle), the first valve66may be configured to shutoff the supply of fuel from the fuel source30to the first fuel circuit32. The second valve68, however, may be configured in its (e.g., fully) open position such that the second fuel circuit36receives a (e.g., full) flow of fuel form the fuel source30. In this first mode, the second fuel injector38(seeFIG.1) is operational and the first fuel injector34(seeFIG.1) is non-operation. Thus, the second fuel injector38may be sized to facilitate full turbine engine operation during its low engine power operation.

In a second mode of operation during, for example, high engine power operation (e.g., engine cruise, aircraft takeoff, etc.), the first valve66may be configured in its (e.g., fully or partially) open position such that the first fuel circuit32receives a (e.g., full or partial) flow of fuel from the fuel source30. The second valve68may also be configured in its (e.g., fully or partially) open position such that the second fuel circuit36receives a (e.g., full or partial) flow of fuel from the fuel source30. In this second mode, both the first fuel injector34(seeFIG.1) and the second fuel injector38(seeFIG.1) are operation. Of course, in other embodiments, the second valve68may be configured to shutoff the supply of fuel from the fuel source30to the second fuel circuit36during the second mode such that the second fuel injector38is non-operational. This may occur, for example, where the first fuel26injected into the flowpath22is heated to a high enough temperature to facilitate, for example, stable combustion and/or complete combustion of the first fuel26.

Referring toFIG.4, the fuel injection system24may include a fuel treatment device70configured with (e.g., embedded in, integral with) the second fuel injector38. The second fuel injector38, for example, may include the fuel treatment device70in an upstream portion thereof, where this fuel treatment device70is positioned upstream of and fluidly coupled with a nozzle orifice72of the second fuel injector38. This fuel treatment device70may be configured to at least partially or completely crack fuel provided to the second fuel injector38from the second fuel circuit36. The fuel treatment device70ofFIG.4may be configured as or otherwise include a heater (e.g., an electric heater) and/or a fluid-to-fluid heat exchanger (e.g., a gas-to-gas heat exchanger). A pathway through the fuel treatment device70may be at least partially (or completely) lined, coated and/or otherwise formed by at least one catalyst74, or partially filled with catalyst-containing material such as pellets or honeycomb. Examples of the catalyst74include, but are not limited to, nickel (Ni), iron (Fe), ruthenium (Ru) and platinum (Pt). The present disclosure, however, is not limited to the foregoing exemplary catalytic materials.

In some embodiments, this fuel treatment device70ofFIG.4may replace the fuel treatment device46(e.g., seeFIG.1); e.g., the fuel treatment device46may be omitted and the second fuel circuit36may simply flow the supply fuel to the second fuel injector38and its fuel treatment device70. In other embodiments, the fuel treatment device70ofFIG.4may be provided in addition to and downstream of the fuel treatment device46(seeFIG.1) in the second fuel circuit36.

In some embodiments, referring toFIG.6, the first fuel circuit32may be configured with/include a fuel treatment device76. This fuel treatment device76is configured to partially crack the supply fuel to provide the first fuel26; e.g., a mixture of ammonia gas, hydrogen gas and nitrogen gas. The fuel treatment device76, for example, may be configured as or otherwise include a heater (e.g., an electric heater) and/or a fluid-to-fluid heat exchanger (e.g., a liquid-to-liquid heat exchanger, a gas-to-liquid heat exchanger or a gas-to-gas heat exchanger). A pathway through the fuel treatment device76may be at least partially (or completely) lined, coated and/or otherwise formed by at least one catalyst78, or partially filled with catalyst-containing material such as pellets or honeycomb. Examples of the catalyst78include, but are not limited to, nickel (Ni), iron (Fe), ruthenium (Ru) and platinum (Pt). The present disclosure, however, is not limited to the foregoing exemplary catalytic materials.

In some embodiments, referring toFIG.7, the second fuel circuit36may be configured with/include a fuel separator80. This fuel separator80is fluidly coupled inline (e.g., serially) between the fuel treatment device46and the second fuel injector38. The fuel separator80is configured to separate the at least partially (or completely) cracked supply fuel into two or more groupings. For example, following the partial cracking of the ammonia via the fuel treatment device46, the fuel separator80may receive the (remaining/uncracked) ammonia gas, the hydrogen gas and the nitrogen gas. The fuel separator80may separate these components into two groupings. The first grouping (e.g., the second fuel28) may be/(e.g., substantially or only) include the hydrogen gas. The second grouping (e.g., a byproduct of providing the first fuel26) may be/(e.g., substantially or only) include a mixture of the (remaining/uncracked) ammonia gas and the nitrogen gas. Of course, in other embodiments, the first grouping may also include the nitrogen gas and/or the second grouping may (e.g., substantially or completely) omit the nitrogen gas.

The fuel separator80may retain the first grouping (H2gas, or H2gas and N2gas) within the second fuel circuit36(downstream of the fuel separator80) for subsequent delivery to the second fuel injector38. The second fuel28directed into the flowpath22by the second fuel injector38may thereby be substantially pure hydrogen gas, or a mixture (e.g., substantially) of hydrogen gas and nitrogen gas. The fuel separator80, however, may remove the second grouping (e.g., NH3gas and N2gas, or NH3gas) from the second fuel circuit36. The fuel separator80, for example, may divert the second grouping from the second fuel circuit36and into the first fuel circuit32via a bridge82for combination with, for example, the supply fuel received from the fuel source30. The first fuel26directed into the flowpath22by the first fuel injector34may thereby substantially be a mixture (e.g., substantially) of ammonia gas and nitrogen gas, or a mixture (e.g., substantially) of ammonia gas, nitrogen gas and hydrogen gas. In addition or alternatively, the fuel separator80may divert some or all of the second grouping from the second fuel circuit36back into the fuel source30via an optional return line83, either directly or after cooling and condensing the NH3, for later use.

In some embodiments, still referring toFIG.7, the second fuel circuit36may be configured with an additional fuel reservoir84. This fuel reservoir84is configured to receive the second fuel28from the fuel separator80, or alternatively from the fuel treatment device46where, for example, the fuel separator80is omitted. The fuel reservoir84is configured to store the second fuel28for subsequent provision to the second fuel injector38. For example, the fuel reservoir84may be charged (e.g., filled) during normal turbine engine assembly operation; e.g., where the fuel treatment device46is operable to sufficiently crack the supply fuel. However, when the turbine engine is in a low power mode of operation (e.g., during initial startup), the fuel reservoir84may supply some or all of the stored second fuel28to the second fuel injector38when, for example, the fuel treatment device46cannot sufficiently crack the supply fuel. Of course, in other embodiments, the fuel reservoir84may also or alternatively provide the second fuel28to the second fuel injector38during other mode(s) of operation; e.g., to boost fuel delivery to the second fuel injector38during high engine power operation.

The fuel reservoir84is described above as being charged (e.g., filled) by the output from the fuel separator80or the fuel treatment device46. In some embodiments, however, the fuel reservoir84may also or alternatively be charged by another fuel source86outside of the turbine engine; e.g., a ground based fuel truck, a ground based pump, etc.

In some embodiments, still referring toFIG.7, the second fuel injector38may be configured to receive the second fuel28(or another fuel such as, for example, pure hydrogen gas) from another fuel source88outside of the turbine engine. The second fuel injector38, for example, may be fluidly coupled to the fuel source88during, for example, turbine engine startup and/or turbine engine shutdown. This fuel source88may be a ground based fuel truck, a ground based pump, or other device that is readily available, for example, at an aircraft gate. Thus, the second fuel injector38may receive sufficient second fuel28even where the fuel reservoir84is depleted (or omitted) and/or the fuel treatment device46is not yet (e.g., fully) functional.

In some embodiments, still referring toFIG.7, the first fuel injector34may include one or more fuel injector orifices90; e.g., nozzle orifices. The turbine engine assembly20ofFIG.3, for example, includes an air swirler92arranged within the flowpath22; e.g., at (e.g., on, adjacent or proximate) an inlet94into the combustion chamber57. This air swirler92includes a plurality of vanes96arranged in an annular array; e.g., about an outer periphery of the second fuel injector38. One or more or all of the swirler vanes96may be configured with an internal passage that leads to a respective one of the fuel injector orifices90. The first fuel injector34is therefore configured with the air swirler92. The first fuel injector34may thereby mix (e.g., inject) the first fuel26with the swirling (e.g., compressed) air. Of course, in other embodiments, the first fuel injector34may be configured discrete from the air swirler92. The first fuel injector34may thereby direct the first fuel26into the flowpath22upstream or downstream of the air swirler92, or at the air swirler92via, for example, one or more orifices in an outer shroud surrounding the vanes96.

In some embodiments, the first fuel injector34may be one of a plurality of first fuel injectors34arranged circumferentially about, for example, an axial centerline of the turbine engine. The second fuel injector38may also or alternatively be one of a plurality of second fuel injectors38arranged circumferentially about, for example, the axial centerline of the turbine engine.

FIG.8is a schematic, sectional illustration of a portion of the combustor section98of the turbine engine. This combustor section98includes a (e.g., annular) combustor100arranged within the (e.g., annular) diffuser plenum102of a diffuser structure104.

The combustor100includes a (e.g., tubular) combustor outer wall106, a (e.g., tubular) combustor inner wall108and a (e.g., annular) combustor bulkhead110. These combustor elements collectively form the (e.g., annular) combustion chamber57. More particularly, the combustion chamber57extends radially between and to the combustor walls106and108. The combustion chamber57extends axially (in an aft/downstream direction) along the combustor outer wall106and the combustor inner108from the combustor bulkhead110.

The combustor100ofFIG.8also includes a (e.g., annular) combustor cowl112. This combustor cowl112is connected to the combustor bulkhead110and/or the combustor walls106and108. The combustor cowl112and the combustor bulkhead110may collectively form the cowl plenum114therebetween. The cowl plenum114ofFIG.8, for example, extends axially between and to an axial end of the combustor cowl112and the combustor bulkhead110. The cowl plenum114extends radially between opposing radial inner and outer sides of the combustor cowl112.

The combustion chamber57may receive (e.g., compressed) air from the compressor section of the turbine engine through the diffuser plenum102. For example, the air compressed by the compressor section may flow into the diffuser plenum102via the pre-diffuser passage116. The air within the diffuser plenum102may flow into the cowl plenum114via one or more inlets118(one visible inFIG.8) in the combustor cowl112. The air within the cowl plenum114may flow into the combustion chamber57through one or more of the swirlers92. Note, each air swirler92or a select subset of the swirlers92may be associated with a respective one of the second fuel injectors38. The air flowing from the cowl plenum114and the swirlers92may account for a majority of/substantially all of the air (e.g., besides cooling air) entering the combustion chamber57where, for example, the combustor100is configured as a fuel-lean combustor. Alternatively, one or more of the combustor walls106and108may each include one or more quench apertures for admitting additional quench air120from the diffuser plenum102into the combustion chamber57where, for example, the combustor100is configured as a fuel-rich (rich-quench-lean (RQL)) combustor.

In some embodiments, one or more of the first fuel injectors34may be configured to direct the first fuel26into the cowl plenum114. The first fuel26may thereby mix with the (e.g., compressed) air that enters the combustion chamber57through the air swirler(s)92prior to flowing through the swirler(s)92. By mixing the first fuel26with the air upstream of the swirlers92/inlets94, the amount of fuel that is mixed downstream of the swirlers92(and/or other flow obstacles/impediments) may be reduced. This reduction of downstream fuel injection (e.g., fuel injected directly into the combustion chamber57) may facilitate a more rapid and/or complete mixing of the (e.g., compressed) air and the fuel prior to combustion.

In some embodiments, one or more other components122and124of the turbine engine may also receive the air from the diffuser plenum102, for example, for cooling those component122and124. Examples of the components122and124include, but are not limited to, one or more arrays of turbine vanes, one or more arrays of turbine rotor blades, one or more blade outer air seals (BOAS), etc. By directing the first fuel26into the flowpath22within the cowl plenum114, the first fuel26may flow directly into the combustion chamber57via the swirlers92. Thus, the quench apertures (if included) and/or the air cooled components122and124may receive substantially or completely pure air for cooling.

In some embodiments, referring toFIG.9, the combustor100may be configured with/include a (e.g., tubular) convector wall126. This convector wall126is configured to form a (e.g., annular) flow passage128with the combustor100. A forward/upstream end of the convector wall126ofFIG.9, for example, is connected to the outer side of the combustor cowl112. The convector wall126is spaced inward from an outer wall of the diffuser structure104such that the diffuser plenum102is formed radially between the wall126and the diffuser structure104. The convector wall126is spaced radially out from and extends axially along the combustor outer wall106to a distal end. An inlet130to the passage128is formed between the convector wall126and the combustor outer wall106at the distal end of the convector wall126. With this arrangement, the passage128may flow the air along the combustor outer wall106before entering the cowl plenum114. Note, the inlets118to the cowl plenum114(seeFIG.8) may be omitted such that (e.g., substantially) all of the air entering the cowl plenum114and, thus, the combustion chamber57through the swirlers92first enters the passage128through its passage inlet130.

In some embodiments, one or more of the first fuel injectors34may be configured to direct the first fuel26into the passage128at (e.g., on, adjacent or proximate) the passage inlet130. Directing the first fuel26into the passage128provides additional time and space for the first fuel26to mix with the air prior to entering the combustion chamber57. The fuel-air mixture may also provide convective cooling for the combustor outer wall106. Again, with this embodiment, the quench apertures (if included) and/or the air cooled components122and124may receive substantially or completely pure air for cooling.

In some embodiments, referring toFIG.10, the combustor100may be configured with/include a (e.g., tubular) convector wall132. This convector wall132is configured to form a (e.g., annular) flow passage134with the combustor100. A forward/upstream end of the convector wall132ofFIG.10, for example, is connected to the outer side of the combustor cowl112. The convector wall132is spaced inward from the outer wall of the diffuser structure104such that the diffuser plenum102is formed radially between the convector wall132and the diffuser structure104. The convector wall132is spaced radially out from and extends axially along the combustor outer wall106to a distal end. This distal end is connected to the combustor outer wall106at (e.g., on, adjacent or proximate) an aft, downstream end of the combustor outer wall106; e.g., axially aft of the quench apertures if included. Alternatively, referring toFIG.11, the distal end of the convector wall132may be connected to the combustor outer wall106at an axial intermediate point (e.g., midpoint) along the combustor100; e.g., axially forward of the quench apertures if included. The passage134may be fluidly coupled with the cowl plenum114via, for example, one or more apertures136in the outer side of the combustor cowl112. In addition, the inlets118to the cowl plenum114are included such that air may enter the cowl plenum114from the diffuser plenum102. With this arrangement, the passage134may flow the air along the combustor outer wall106before entering the combustion chamber57via, for example, cooling apertures (not visible inFIGS.10and11) in the combustor outer wall106and/or the quench apertures (if included).

In some embodiments, one or more of the first fuel injectors34may be configured to direct the first fuel26into the cowl plenum114(and/or directly into the passage134). Directing the first fuel26into the cowl plenum114and/or the passage134provides additional time and space for the first fuel26to mix with the air prior to entering the combustion chamber57. In the embodiment ofFIG.10, fuel enriched quench air120′ (e.g., quench air mixed with the first fuel) may be directed into the combustion chamber57via the quench apertures in the combustor outer wall106(when included). The fuel-air mixture may also provide convective cooling for the combustor outer wall106. Again, with this embodiment, the air cooled components122and124may receive substantially or completely pure air for cooling. The quench apertures ofFIG.11(if included) may also receive substantially or completely pure air for cooling.

In some embodiments, referring toFIG.12, one or more of the first fuel injectors34may be configured to direct the first fuel26into the pre-diffuser passage116, or directly into the diffuser plenum102. However, to prevent a mixture of the first fuel26and the air from flowing to the air cooled components122and124, thereby ensuring that all fuel may enter the combustor100, the turbine engine assembly20may include one or more air conduits138and140. Each first (e.g., outer) air conduit138may tap the air from the flowpath22, upstream of the first fuel injectors34. Each first air conduit138may direct the tapped air to one or more respective air cooled components122and124. Similarly, each second (e.g., inner) air conduit140may tap the air from the flowpath22, upstream of the first fuel injectors34. Each second air conduit140may direct the tapped air to one or more respective air cooled components122and124.

In some embodiments, one or more of the second fuel injectors38ofFIGS.8-12may be reconfigured to direct (e.g., inject) the second fuel28into the flowpath22(e.g., the combustion chamber57) with one or more additives; e.g., diluents. Examples of the additives may include, but are not limited to, water, steam, methane, natural gas, kerosene, jet fuel, gasoline, diesel, another petroleum or distillate fuel, another hydrocarbon fuel such as biofuel or sustainable aviation fuel (SAF), or mixture of one or more of the foregoing additives. In still other embodiments, one or more of the second fuel injectors38may be reconfigured to direct (e.g., inject) one or more of the foregoing additives as the second fuel28without, for example, a portion derived from the fuel supply; e.g., H2, N2and/or NH3. More particularly, in other embodiments, one or more of the second fuel injectors38may be fluidly coupled with a fuel source (e.g., reservoir) other than the fuel source30(e.g., seeFIG.1).

FIG.13a side cutaway illustration of a geared turbine engine142with which the turbine engine assemblies20described above can be included. This turbine engine142extends along the axial centerline144between an upstream airflow inlet146and a downstream airflow exhaust148. The turbine engine142includes the fan section150, the compressor section151, the combustor section98and the turbine section152. The compressor section151includes a low pressure compressor (LPC) section151A and a high pressure compressor (HPC) section151B. The turbine section152includes a high pressure turbine (HPT) section152A and a low pressure turbine (LPT) section152B.

The engine sections150,151A,151B,98,152A and152B are arranged sequentially along the centerline144within an engine housing154. This engine housing154includes an inner case156(e.g., a core case) and an outer case158(e.g., a fan case). The inner case156may house one or more of the engine sections151A,151B,98,152A and152B; e.g., an engine core. The outer case158may house at least the fan section150.

Each of the engine sections150,151A,151B,152A and152B includes a respective rotor160-164. Each of these rotors160-164includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed, adhered and/or otherwise attached to the respective rotor disk(s).

The fan rotor160is connected to a gear train166, for example, through a fan shaft168. The gear train166and the LPC rotor161are connected to and driven by the LPT rotor164through a low speed shaft169. The HPC rotor162is connected to and driven by the HPT rotor163through a high speed shaft170. The shafts168-170are rotatably supported by a plurality of bearings172; e.g., rolling element and/or thrust bearings. Each of these bearings172is connected to the engine housing154by at least one stationary structure such as, for example, an annular support strut.

During operation, air enters the turbine engine142through the airflow inlet146. This air is directed through the fan section150and into the core flowpath174(e.g., the flowpath22) and a bypass flowpath176. The core flowpath174extends sequentially through the engine sections151A,152B,98,152A and152B. The air within the core flowpath174may be referred to as “core air”. The bypass flowpath176extends through a bypass duct, which bypasses the engine core. The air within the bypass flowpath176may be referred to as “bypass air”.

The core air is compressed by the compressor rotors161and162and directed into the combustion chamber57in the combustor section98. The fuel (e.g., the combination of the NH3gas, the H2gas, the N2gas, etc.) is injected into the core flowpath174(e.g., the flowpath22) as described above and mixed with the compressed core air to provide a fuel-air mixture. This fuel air mixture is ignited within the combustion chamber57and combustion products thereof flow through and sequentially cause the turbine rotors163and164to rotate. The rotation of the turbine rotors163and164respectively drive rotation of the compressor rotors162and161and, thus, compression of the air received from a core airflow inlet. The rotation of the turbine rotor164also drives rotation of the fan rotor160, which propels bypass air through and out of the bypass flowpath176. The propulsion of the bypass air may account for a majority of thrust generated by the turbine engine142ofFIG.13, e.g., more than seventy-five percent (75%) of engine thrust. The turbine engine of the present disclosure, however, is not limited to the foregoing exemplary thrust ratio.

The turbine engine assembly20may be included in various turbine engines other than the one described above. The turbine engine assembly20, for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the turbine engine assembly20may be included in a turbine engine configured without a gear train. The turbine engine assembly20may be included in a geared or non-geared turbine engine configured with a single spool, with two spools (e.g., seeFIG.13), or with more than two spools. The turbine engine may be configured as a turbofan engine, a turbojet engine, a propfan engine, a pusher fan engine or any other type of turbine engine. The present disclosure therefore is not limited to any particular types or configurations of turbine engines.