Hybrid turbo shaft and solid oxide fuel cell propulsion system and related methods

Abstract

The present disclosure relates to hybrid turbo-shaft and solid oxide fuel cell propulsion systems and related methods. The hybrid propulsion systems utilize liquid natural gas solid oxide fuel cells in a manner practical for use in an aircraft, avoid the use of heavy batteries, provide transient response times suitable for use in an aircraft, and / or simplify the use of a reactant pre-conditioning system operably coupled to a pair of compressors and turbines of a solid oxide fuel cell. Such hybrid propulsion systems for an aircraft can include a liquid natural gas turbo-shaft engine, a turbo-generator operably coupled to the turbo-shaft engine, a liquid natural gas solid oxide fuel cell, and an electric fan. The electric fan can be configured to generate thrust for the aircraft and can be powered by the turbo-generator and / or the solid oxide fuel cell. The turbo-shaft bleed air can be used to pre-condition fuel cell reactants, and the liquid natural gas can be pre-heated by fuel exhaust from the solid oxide fuel cell.

Description

Technical Field

[0001] This disclosure relates to propulsion systems, and more specifically to solid oxide fuel cell propulsion systems using liquid natural gas. Background Technology

[0002] Turboshaft engines are a form of jet engine that have long been used in propulsion systems for aircraft and other vehicles or machines. Attempts have been made to design turboshaft engines with reduced or zero CO2 emissions and other greenhouse gas emissions. One such solution (electric propulsion) suffers from excessive weight, making it too large to be implemented in the aerospace industry. Attempts have been made to incorporate fuel cells into such propulsion systems; however, conventional fuel cell systems suffer from slow transient response times unsuitable for aviation and may disadvantageously require complex systems to pre-condition (heat and pressurize) the fuel cell reactants. Summary of the Invention

[0003] The hybrid propulsion system disclosed herein can be configured to reduce overall aircraft propulsion system emissions and improve its efficiency using alternative energy sources and constructions not conceived in the prior art, while avoiding the drawbacks of prior art systems, such as excessive weight and slow transient response times from electric propulsion. By addressing these shortcomings of prior art systems, the hybrid propulsion system of this disclosure can practically utilize liquefied natural gas solid oxide fuel cells in aircraft. The hybrid propulsion system of this disclosure can also be configured to simplify the reactant preconditioning system.

[0004] In the example, the hybrid propulsion system for an aircraft may include a liquid natural gas turboshaft engine, a turbogenerator operatively coupled to the turboshaft engine, a liquid natural gas solid oxide fuel cell, and an electric fan. The electric fan may be configured to generate thrust for the aircraft and may be powered by the turbogenerator and / or the solid oxide fuel cell. Aircraft including a fuselage, fuselage-supported wings, a turboshaft engine, and such a hybrid propulsion system are also within the scope of this disclosure.

[0005] A method for providing thrust to an aircraft via a hybrid propulsion system is also disclosed. Such a method may include generating a first electric power via a turbine generator of a liquid natural gas turboshaft engine operably coupled to the aircraft, and generating a second electric power via a liquid natural gas solid oxide fuel cell. An electric fan may be powered by the first and / or the second electric power, thereby generating thrust to the aircraft via the operation of the electric fan. The first and second electric powers may be provided to the electric fan substantially simultaneously. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of an exemplary aircraft according to the present disclosure.

[0007] Figure 2 This is a schematic diagram illustrating a non-exclusive example of a hybrid propulsion system according to the present disclosure.

[0008] Figure 3 This is a flowchart schematically illustrating the method according to this disclosure. Detailed Implementation

[0009] Figure 1 A non-exclusive example of an aircraft 12 that may include one or more hybrid propulsion systems 10 according to this disclosure is shown. Although shown as a fixed-wing airliner including a fuselage 60 having a cabin 18, two wings 62 supported by the fuselage 60, a tail 14, and a jet engine 16 supported by each wing 62, other configurations of the aircraft 12 are within the scope of this disclosure, including, for example, rotorcraft, military aircraft, autonomous aircraft, etc. Figure 1 One or more components of the hybrid propulsion system 10 are schematically shown, and optionally all of them can be supported and / or housed in one or more of the fuselage 60 and / or wings 62 of the aircraft 12.

[0010] Figure 2 This schematically illustrates a non-exclusive example of a hybrid propulsion system 10 according to the present disclosure. Generally, in Figure 2 In this document, solid lines indicate elements that may be included in a given example, while dashed lines indicate elements that are optional for a given example or correspond to a specific example. However, elements shown in solid lines are not required for all examples of this disclosure, and elements shown in solid lines may be omitted from a specific example without departing from the scope of this disclosure.

[0011] like Figure 2 As schematically shown, a hybrid propulsion system 10 for an aircraft (e.g., aircraft 12) includes at least a liquid natural gas turboshaft engine 20, a turbogenerator 22 operatively coupled to the turboshaft engine 20, a liquid natural gas solid oxide fuel cell 24, and an electric fan 26. The electric fan 26 is configured to generate thrust for the aircraft and is powered by the turbogenerator 22 and / or the solid oxide fuel cell 24. In some examples, the turbogenerator 22 and the solid oxide fuel cell 24 simultaneously supply power to the electric fan 26. The hybrid propulsion system 10 may include a fuel system 72 configured to supply liquid natural gas to the turboshaft engine 20 and the solid oxide fuel cell 24.

[0012] The turboshaft engine 20 generally includes a low-pressure compressor 28, a high-pressure compressor 30, a high-pressure turbine 32, and a low-pressure turbine 34. A combustor 40 (e.g., a combustion chamber or burner) is housed within the turboshaft engine 20, typically between the high-pressure compressor 30 and the high-pressure turbine 32. A first shaft 36 is coupled to the high-pressure compressor 30 and the high-pressure turbine 32 such that the high-pressure compressor 30 can be driven by the high-pressure turbine 32. A second shaft 38 is coupled to the low-pressure compressor 28 and the low-pressure turbine 34 within the turboshaft engine 20 such that the low-pressure compressor 28 can be driven by the low-pressure turbine 34. The main inlet 42 receives ambient air or air from the environment and modulates the ambient air for use in mixing downstream components of the propulsion system 10, for example, by reducing the Mach number of the ambient air. The air is then delivered to the low-pressure compressor 28 (i.e., the low-pressure compressor 28 receives air from the main inlet 42), which pressurizes (compresses) the air from the main inlet 42. The low-pressure compressor 28 sends a first portion 44 of pressurized air to the high-pressure compressor 30 for further pressurization (and then to the burner 40 for combustion), while a second portion 46 of pressurized air (also referred to herein as bleed air 46) is directed along the bleed air path 48 to the solid oxide fuel cell 24. In other words, the bleed air 46, after being compressed by the low-pressure compressor 28, is drawn from the turboshaft engine 20 to provide pre-conditioned air to the solid oxide fuel cell 24.

[0013] The low-pressure compressor 28 and an additional compressor 50 located downstream of the low-pressure compressor 28 along the bleed gas flow path 48 pre-condition the bleed gas 46 for use in the solid oxide fuel cell 24 by pressurizing the bleed gas and increasing its temperature due to the compression of the bleed gas. After the bleed gas 46 is compressed in both the low-pressure compressor 28 and the compressor 50, the bleed gas 46 continues along the bleed gas flow path 48 and is delivered to the cathode 52 of the solid oxide fuel cell 24 and thus serves as reactant or source air for the solid oxide fuel cell 24.

[0014] Compressor 50 is part of a compressor and turbine pair 54, which also includes a turbine 56 and a shaft 58 operatively connecting compressor 50 and turbine 56 such that compressor 50 is driven by power from turbine 56. Compressor 50 is upstream of cathode 52 of solid oxide fuel cell 24 to deliver bleed air 46 to cathode 52, and turbine 56 is downstream of cathode 52 to receive fuel cell exhaust 64 from solid oxide fuel cell 24. Compressor and turbine pair 54 can be used to extract energy from fuel cell exhaust 64 exiting solid oxide fuel cell 24 to improve the efficiency of hybrid propulsion system 10, rather than wasting heat from fuel cell exhaust 64. For example, compressor and turbine pair 54 can be configured to use the energy extracted from fuel cell exhaust 64 to adjust or control one or more conditions for fuel cell reactants (e.g., bleed air 46) for solid oxide fuel cell 24. In some examples, turbine 56 is configured to limit the power extraction from fuel cell exhaust 64 to maintain the pressure of fuel cell exhaust 64 above a desired threshold pressure. Additionally or alternatively, the compressor and turbine pair 54 can be configured to slightly adjust the reactant conditions rather than primarily pressurize the reactants, and thus the compressor and turbine pair 54 can be used as a simplified device for pre-regulating the bleed air 46 of the solid oxide fuel cell 24 compared to conventional fuel cell systems that require complex regulation systems.

[0015] In some examples, the hybrid propulsion system 10 includes a splitter 66 located upstream of the turbine 56 and downstream of the cathode 52 of the solid oxide fuel cell 24, and a mixer 68 located downstream of the turbine 56. In such an example, the mixer 68 receives turbine exhaust 70 from the turbine 56 and fuel cell exhaust 64 from the solid oxide fuel cell 24, and mixes the turbine exhaust 70 with the fuel cell exhaust 64. The splitter 66 and the mixer 68 may be configured to control the outlet pressure of the turbine exhaust 70 leaving the turbine 56.

[0016] As described above, liquid natural gas from fuel system 72 is used as fuel / reactant for turboshaft engine 20 and solid oxide fuel cell 24. Liquid natural gas from fuel system 72 can also be used in the steam generation process within hybrid propulsion system 10. In some examples, liquid natural gas from fuel system 72 is used to cool engine exhaust 74 from turboshaft engine 20 and condense water in engine exhaust 74. Alternatively or concurrently, liquid natural gas from fuel system 72 can be preheated using engine exhaust 74 for use in solid oxide fuel cell 24. For this purpose, hybrid propulsion system 10 may include condenser 76, regenerator 78, and / or water extractor 80. Condenser 76 may receive liquid natural gas 122 from fuel system 72 and evaporate (e.g., vaporize) the liquid natural gas to form gaseous natural gas 82 (i.e., condenser 76 may be configured to convert liquid natural gas 122 into gaseous natural gas 82). In other words, liquid natural gas 122 from fuel system 72 may be preheated by engine exhaust 74 in condenser 76 before being supplied to the anode 90 of solid oxide fuel cell 24. The condenser 76 can also condense liquid water in the engine exhaust 74 (e.g., water vapor) leaving the turbine shaft engine 20.

[0017] A regenerator 78 may be located downstream of a condenser 76 and may receive fuel cell exhaust 64 from a solid oxide fuel cell 24 (which may be via a turbine 56 and a mixer 68). The regenerator 78 may be configured to supply gaseous natural gas 82 to a turboshaft engine 20 (e.g., to a combustor 40). In some examples, the regenerator 78 uses heat from the fuel cell exhaust 64 to further heat the gaseous natural gas from the condenser 76. A water extractor 80 may be configured to receive air 84 containing liquid water from the condenser 76, along with the gaseous natural gas 82. For example, a splitter 86 downstream of the regenerator 78 may separate the gaseous natural gas 82 leaving the regenerator 78, such that some gaseous natural gas 82' is directed to the turboshaft engine 20, while some gaseous natural gas 82'' is directed to the water extractor 80. Water extractor 80 may be configured to generate water vapor and add (e.g., mix) it to gaseous natural gas 82'' to supply humidified natural gas 88 to the anode 90 of solid oxide fuel cell 24. In some examples, anode 90 has an internal reformer to convert natural gas into hydrogen-rich gas, while in other examples, an external reformer 128 is provided upstream of anode 90 to convert natural gas into hydrogen-rich gas.

[0018] In some examples, the hybrid propulsion system 10 includes a turbine shaft mixer 92 downstream of the regenerator 78 and the low-pressure turbine 34. In such examples, the turbine shaft mixer 92 is configured to mix the high-pressure fuel cell exhaust 64 with the exhaust stream (e.g., engine exhaust 74) exiting the low-pressure turbine 34 of the turbine shaft engine 20 after the fuel cell exhaust 64 has passed through the regenerator 78, which can generate more electricity. This can be achieved because the fuel cell exhaust 64 has a pressure similar to that of the engine exhaust 74 exiting the low-pressure turbine 34. The high pressure of the fuel cell exhaust 64 can be achieved via the disclosed hybrid propulsion system 10 because less energy is extracted through the turbine 56 compared to a conventional hybrid gas turbine fuel cell. This mixing of the fuel cell exhaust 64 back into the turbine shaft engine 20 (e.g., mixing the fuel cell exhaust 64 and the engine exhaust 74) can increase the power generated by the turbine generator 22, which receives the engine exhaust 74 from the turbine shaft engine 20. Furthermore, the turbine generator 22 extracts energy from the engine exhaust 74 to generate electricity to power the electric fan 26, as shown in 96. In some examples, a turbine generator 22 and a second generator 100, coupled to shaft 98, generate electricity 96. Electricity 108 output from the solid oxide fuel cell 24 can be combined with electricity 96 from the turbine generator 22 via bus 102 after a DC-AC converter 116 converts direct current (DC) power to alternating current (AC) power, resulting in combined electricity, denoted as 118. The combined electricity 118 can pass through an inverter 104 before reaching the electric motor 106, which can be operatively coupled to the electric fan 26 via fan shaft 110. In this way, the combined electricity 118 from the turbine generator 22 and the solid oxide fuel cell 24 can cause the operation of the electric motor 106, which powers the electric fan 26, thereby generating thrust for the aircraft. In some examples, the electric fan 26 is coaxial with the turbine shaft engine 20. In some examples, auxiliary inlet 112 allows bypass airflow 120 to be drawn into electric fan 26, while auxiliary nozzle 114 is configured to expand the propulsive fan air 120 from electric fan 26 to generate thrust.

[0019] The electric fan 26 may be powered solely by the solid oxide fuel cell 24, solely by the turbine generator 22, and / or by both the solid oxide fuel cell 24 and the turbine generator 22. In some examples, power for the electric fan 26 may be supplied simultaneously from both the solid oxide fuel cell 24 and the turbine generator 22. The hybrid propulsion system 10 may include an electric motor controller configured to control the power sources and relative electric forces supplied to the electric fan 26. For example, the electric motor controller may be configured to allocate a ratio of electrical load to the solid oxide fuel cell 24 and the turbine generator 22, thereby determining the ratio of fuel consumption of the solid oxide fuel cell 24 and the turbine generator 22. The ratio of fuel consumption may further determine the fuel ratio of the amount of fuel allocated by the fuel system 72 to each of the turbine shaft engine 20 and the solid oxide fuel cell 24. The disclosed hybrid propulsion system 10 may be configured such that the transient response time of the electric fan 26 is fast enough to be suitable for use in an aircraft. For example, compared to a conventional system using only fuel cells, the operative connection of the solid oxide fuel cell 24 and the turboshaft engine 20 in the hybrid propulsion system 10 of this disclosure can have the technical effect of reducing (e.g., accelerating) the transient response time of the electric fan 26. The faster transient response in the disclosed hybrid propulsion system 10 can be manipulated by the turboshaft or gas turbine side (e.g., the turboshaft engine 20), and then, after the operation of the hybrid propulsion system 10 approaches a steady state, power distribution can be transferred from the gas turbine side to the fuel cell side (e.g., the solid oxide fuel cell 24). In this way, the disclosed hybrid propulsion system 10 can be configured to have the advantage of the faster transient response time of the turboshaft engine 20, while also obtaining fuel efficiency benefits from the solid oxide fuel cell 24.

[0020] The controller (such as the described electric motor controller) can be any suitable one or more devices configured to perform the functions of the electric motor controller discussed herein. For example, the controller may include one or more of an electronic controller, a dedicated controller, a special purpose controller, a personal computer, a special purpose computer, a display device, a logic device, a memory device, and / or a memory device having a computer-readable medium adapted to store computer-executable instructions for implementing aspects of the system and / or method according to this disclosure.

[0021] Compared to existing propulsion systems, the benefits of the disclosed hybrid propulsion system 10 may include reduced emissions and / or improved efficiency across the entire aircraft propulsion system. The disclosed hybrid propulsion system 10 utilizes alternative energy sources and configurations not conceived in the prior art and is configured to avoid the heavy batteries required by existing electric systems. Furthermore, since the disclosed hybrid propulsion system 10 utilizes bleed air 46 as the pressurized air reactant for the solid oxide fuel cell 24, a complex pre-conditioning system is avoided, which is another advantage over the prior art. Additionally or alternatively, the hybrid propulsion system 10 according to this disclosure can provide improved transient response time by coordinating the operation of the solid oxide fuel cell 24 and the turboshaft engine 20.

[0022] The scope of this disclosure also includes aircraft that include the disclosed hybrid propulsion system 10, such as... Figure 1 The aircraft 12 is schematically illustrated. Such an aircraft 12 may include a fuselage 60, wings 62 supported by the fuselage 60, one or more jet engines 16 (which may be turboshaft engines 20 as described herein), and a hybrid propulsion system 10. In some examples, at least a portion of the hybrid propulsion system 10 is supported by and / or housed within the wings 62. For example, the solid oxide fuel cell 24, compressor and turbine pair 54, and / or regenerator 78 of the hybrid propulsion system 10 may be housed within the wings 62. Alternatively, an electric fan 26 may be supported by the wings 62. In some examples, the turboshaft engine 20 is supported by the tail section 14 of the fuselage 60 and / or the wings 62. In some examples, a turbine generator 22, a condenser 76, and / or a turboshaft mixer 92 are housed within the turboshaft engine 20. An electric motor 106 driving the electric fan 26 may be housed in an electric fan nacelle. Embodiments of the aircraft 12 may include, but are not limited to, a single-channel turbo-electric aircraft.

[0023] Figure 3 A flowchart illustrating a schematic, non-exclusive example of method 200 according to this disclosure is provided. Figure 3 In the diagram, some steps are shown in dashed boxes, indicating that these steps may be optional or may correspond to an optional version of method 200 according to this disclosure. That is, not all methods 200 according to this disclosure need to include the steps shown in solid boxes. Figure 3 The method 200 and steps shown are not limiting, and other methods and steps are within the scope of this disclosure, including methods having more or fewer steps than shown, as understood from the discussion herein.

[0024] A method 200 for providing thrust to an aircraft (e.g., aircraft 12) via a hybrid propulsion system (e.g., hybrid propulsion system 10) typically includes: at 202, generating a first electrical force via a turbine generator (e.g., turbine generator 22); at 204, generating a second electrical force via a liquid natural gas solid oxide fuel cell (e.g., solid oxide fuel cell 24); and at 206, supplying power to an electric fan (e.g., electric fan 26) via the first and / or second electrical forces, thereby generating thrust to the aircraft via the operation of the electric fan. In other words, supplying power to the electric fan at 206 includes optionally providing the first and / or second electrical forces to the electric fan simultaneously. For this purpose, the turbine generator is operatively coupled to the aircraft's liquid natural gas turboshaft engine (e.g., turboshaft engine 20).

[0025] Method 200 may include cooling engine exhaust from a turboshaft engine (e.g., engine exhaust 74) via liquefied natural gas at 208. Alternatively, at 210, liquefied natural gas from a fuel system (e.g., fuel system 72) may be preheated via engine exhaust (e.g., the exhaust stream from low-pressure turbine 34). Some methods 200 include condensing liquefied natural gas from the fuel system of a hybrid propulsion system and engine exhaust from the turboshaft engine at 212 (e.g., via condenser 76), followed by reheating the gaseous natural gas from the condenser at 214 (e.g., via regenerator 78) using fuel cell exhaust from a solid oxide fuel cell. In some examples, reheating at 214 includes preheating the gaseous natural gas using fuel cell exhaust from the solid oxide fuel cell. Alternatively, some methods 200 include extracting water at 216 and generating water vapor from the exhaust from the turboshaft engine (e.g., via water extractor 80), and adding the water vapor to the natural gas from the fuel system at 218 to provide humidified natural gas to the anode (e.g., anode 90) of the solid oxide fuel cell.

[0026] Method 200 may include extracting bleed gas from a low-pressure compressor (e.g., low-pressure compressor 28) of a turboshaft engine at 220; and providing the extracted bleed gas to the cathode (e.g., cathode 52) of a solid oxide fuel cell at 222. Prior to the provision at 222, the bleed gas (e.g., reactants) of the solid oxide fuel cell may be pre-conditioned at 224 via the low-pressure compressor of the turboshaft engine and exhaust gas from the solid oxide fuel cell (e.g., fuel cell exhaust gas 64). Some methods 200 include controlling one or more conditions of the fuel reactants (e.g., bleed gas) of the solid oxide fuel cell at 226 via a compressor and turbine pair (e.g., compressor and turbine pair 54), wherein the compressor of the compressor and turbine pair receives bleed gas from the low-pressure compressor of the turboshaft engine. At 228, energy may be extracted from the fuel cell exhaust gas to condition the bleed gas at the cathode of the solid oxide fuel cell via the compressor and turbine pair. In some examples, the pressure of the fuel cell exhaust gas is maintained at 230 by limiting or controlling the energy extracted from the fuel cell exhaust gas via the compressor and turbine pair, wherein the turbine of the compressor and turbine pair receives fuel cell exhaust gas from the cathode of the solid oxide fuel cell. Alternatively, the pressure of turbine exhaust from the compressor and turbine pair (e.g., turbine exhaust 70 from turbine 56) can be controlled or limited at 230 via a splitter upstream of the turbine and a mixer downstream of the turbine (e.g., splitter 66 and mixer 68). At 232, fuel cell exhaust can be mixed with the exhaust stream from the low-pressure turbine exiting the turbine shaft engine via a turbine shaft mixer downstream of the regenerator (e.g., turbine shaft mixer 92), thereby increasing the power generated by the turbine generator. In some examples, at 234, the ratio of power generated by the solid oxide fuel cell to power generated by the turbine generator is controlled, for example, via the electric motor control system of the hybrid propulsion system.

[0027] The following paragraphs describe illustrative, non-exclusive examples of the inventive subject matter according to this disclosure: A1. A hybrid propulsion system (10) for an aircraft (12), the hybrid propulsion system (10) comprising: Liquid natural gas turboshaft engine (20); A turbine generator (22) is operatively connected to a turbine shaft engine (20). Liquid natural gas solid oxide fuel cell (24); and An electric fan (26) is configured to generate thrust for the aircraft (12), wherein the electric fan (26) is powered by a turbine generator (22) and / or a solid oxide fuel cell (24).

[0028] A1.1. According to paragraph A1, the hybrid propulsion system (10) in which a turbine generator (22) and a solid oxide fuel cell (24) simultaneously provide power to an electric fan (26).

[0029] A2. The hybrid propulsion system (10) according to paragraph A1 or A1.1 also includes a fuel system (72) configured to supply liquid natural gas to the turboshaft engine (20) and the solid oxide fuel cell (24).

[0030] A2.1. According to paragraph A2, the hybrid propulsion system (10) wherein liquid natural gas from the fuel system (72) is configured to cool engine exhaust (74) from the turboshaft engine (20).

[0031] A2.2. A hybrid propulsion system (10) according to any one of paragraphs A2-A2.1, wherein the hybrid propulsion system (10) is configured to preheat liquid natural gas from fuel system (72) using engine exhaust (74) from low-pressure turbine (34) of turboshaft engine (20).

[0032] A2.3. The hybrid propulsion system (10) according to any one of paragraphs A2-A2.3 further includes a condenser (76) that receives liquid natural gas from the fuel system (72).

[0033] A2.4. According to paragraph A2.3, the hybrid propulsion system (10) wherein the condenser (76) vaporizes the liquid natural gas to form gaseous natural gas (82), and wherein the condenser (76) condenses liquid water from engine exhaust (74) leaving the turbine shaft engine (20).

[0034] A2.5. The hybrid propulsion system (10) according to paragraph A2.3 or A2.4 further includes a regenerator (78) downstream of the condenser (76), wherein the regenerator (78) receives fuel cell exhaust (64) from the solid oxide fuel cell (24).

[0035] A2.6. According to paragraph A2.5, the hybrid propulsion system (10) wherein the regenerator (78) supplies gaseous natural gas (82) to the turboshaft engine (20).

[0036] A2.7. Hybrid propulsion system (10) according to paragraph A2.5 or A2.6, wherein a regenerator (78) uses heat from fuel cell exhaust (64) from a solid oxide fuel cell (24) to further heat gaseous natural gas (82).

[0037] A2.8. The hybrid propulsion system (10) according to any one of paragraphs A2.3 to A2.7 further includes a water extractor (80) configured to receive air (84) and liquid water in the air (84) from a condenser (76), wherein the water extractor (80) is further configured to receive gaseous natural gas (82).

[0038] A2.9. According to paragraph A2.8, a hybrid propulsion system (10) wherein a water extractor (80) generates water vapor and adds (mixes) the water vapor to gaseous natural gas (82) to provide humidified natural gas (88) to the anode of a solid oxide fuel cell (24).

[0039] A2.10. A hybrid propulsion system (10) according to any one of paragraphs A2.3-A2.9, wherein a condenser (76) is configured to condense water from engine exhaust (74) from a turboshaft engine (20).

[0040] A2.11. The hybrid propulsion system (10) according to any one of paragraphs A1-A2.10 also includes a low-pressure turbine (34) of a turboshaft engine (20).

[0041] A2.12. A hybrid propulsion system (10) according to any one of paragraphs A1-A2.11, wherein the anode (90) of the solid oxide fuel cell (24) includes an internal reformer configured to convert natural gas into hydrogen-rich gas.

[0042] A2.13. The hybrid propulsion system (10) according to any one of paragraphs A1-A2.11 further includes an external reformer (128) upstream of the anode (90) of the solid oxide fuel cell (24), wherein the external reformer (128) is configured to convert natural gas into hydrogen-rich gas.

[0043] A3. A hybrid propulsion system (10) according to any one of paragraphs A1-A2.13, wherein the turboshaft engine (20) includes a low-pressure compressor (28).

[0044] A4. According to paragraph A3, the hybrid propulsion system (10) wherein the low-pressure compressor (28) is configured to receive air (84) for the solid oxide fuel cell (24) from a main inlet (42) configured to receive ambient air.

[0045] A4.1. According to paragraph A4, the hybrid propulsion system (10) wherein the main inlet (42) is configured to regulate the ambient air for downstream components of the hybrid propulsion system (10) by reducing the Mach number of the ambient air.

[0046] A4.2 Hybrid propulsion system (10) according to paragraph A4 or A4.1, wherein a low-pressure compressor (28) is configured to pre-regulate the bleed gas (46) for the solid oxide fuel cell (24) via compression of the bleed gas (46), the compression pressurizing the bleed gas (46) and raising the temperature of the bleed gas (46).

[0047] A5. A hybrid propulsion system (10) according to any of paragraphs A3-A4.2, wherein a low-pressure compressor (28) is configured to deliver bleed air (46) to a solid oxide fuel cell (24).

[0048] A6. A hybrid propulsion system (10) according to any of paragraphs A3-A5, wherein bleed air (46) drawn from a low-pressure compressor (28) is configured as source air for a solid oxide fuel cell (24).

[0049] A7. The hybrid propulsion system (10) according to any of paragraphs A1-A6 further includes a compressor and a turbine pair (54), wherein the compressor (50) is located downstream of the low-pressure compressor (28) of the turboshaft engine (20) along the bleed air passage (48), wherein the compressor (50) is located upstream of the cathode (52) of the solid oxide fuel cell (24), and wherein the turbine (56) is located downstream of the cathode (52) of the solid oxide fuel cell (24), such that the turbine (56) is configured to receive fuel cell exhaust (64) from the solid oxide fuel cell (24).

[0050] A8. According to paragraph A7, the hybrid propulsion system (10) wherein the compressor and turbine pair (54) is configured to adjust or control one or more conditions for the fuel cell reactants of the solid oxide fuel cell (24).

[0051] A9. According to paragraph A7 or A8, the hybrid propulsion system (10) wherein the compressor and turbine pair (54) is configured to extract energy from fuel cell exhaust (64) from the solid oxide fuel cell (24) to regulate the reactant / entrainment gas (46) at the cathode (52) of the solid oxide fuel cell (24).

[0052] A9.1. A hybrid propulsion system (10) according to any one of paragraphs A7 to A9, wherein the turbine (56) is configured to limit energy extraction from the fuel cell exhaust (64) from the solid oxide fuel cell (24) to maintain the pressure of the fuel cell exhaust (64) from the solid oxide fuel cell (24).

[0053] A10. The hybrid propulsion system (10) according to any one of paragraphs A7 to A9.1 further includes: A shunt (66) is located upstream of the turbine (56) and downstream of the cathode (52) of the solid oxide fuel cell (24); and A mixer (68) is located downstream of the turbine (56), wherein the mixer (68) receives turbine exhaust (70) from the turbine (56) and fuel cell exhaust (64) from the solid oxide fuel cell (24), and wherein the splitter (66) and the mixer (68) are configured to control the outlet pressure of the engine exhaust (74) leaving the turbine (56).

[0054] A11. The hybrid propulsion system (10) according to any one of paragraphs A1 to A10 further includes a turbine shaft mixer (92) downstream of the regenerator (78), wherein the turbine shaft mixer (92) mixes the high-pressure fuel cell exhaust (64) from the solid oxide fuel cell (24) into the exhaust stream from the low-pressure turbine (34) of the turbine shaft engine (20), thereby increasing the power generated by the turbine generator (22).

[0055] A12. According to any of paragraphs A1-A11, the hybrid propulsion system (10) wherein the first pressure of the fuel cell exhaust (64) from the solid oxide fuel cell (24) is similar to the second pressure of the exhaust flow from the low-pressure turbine (34) of the turboshaft engine (20).

[0056] A13. A hybrid propulsion system (10) according to any of paragraphs A1-A12, wherein the hybrid propulsion system (10) is configured such that the transient response time of the electric fan (26) is fast enough to be suitable for the aircraft (12).

[0057] A14. A hybrid propulsion system (10) according to any one of paragraphs A1-A13, wherein a solid oxide fuel cell (24) and a turboshaft engine (20) are operatively coupled together such that the transient response time of an electric fan (26) is reduced (accelerated) compared to a conventional system using only a fuel cell.

[0058] A15. A hybrid propulsion system (10) according to any one of paragraphs A1 to A14, wherein the hybrid propulsion system (10) includes an electric motor controller configured to allocate a ratio of electrical load to a solid oxide fuel cell (24) and a turbine generator (22), thereby determining the ratio of fuel consumption of the solid oxide fuel cell (24) and the turbine generator (22).

[0059] A16. According to paragraph A15, the hybrid propulsion system (10) wherein the fuel consumption ratio determines the amount of fuel allocated by the fuel system (72) to each of the turboshaft engine (20) and the solid oxide fuel cell (24).

[0060] B1. An aircraft (12), comprising: Fuselage (60); Wings (62), which are supported by the fuselage (60); Turboshaft engine (20); and Hybrid propulsion system (10) according to any one of paragraphs A1 to A16.

[0061] B2. According to paragraph B1, the aircraft (12) in which the hybrid propulsion system (10) is supported by the wings (62).

[0062] B3. An aircraft (12) according to any one of paragraphs B1 to B2, wherein at least a portion of the hybrid propulsion system (10) is housed within the wing (62).

[0063] B3.1. According to paragraph B3, the aircraft (12) in which the solid oxide fuel cell (24), the compressor and turbine pair (54) of the hybrid propulsion system (10), and / or the regenerator (78) of the hybrid propulsion system (10) are housed within the wing (62).

[0064] B4. An aircraft (12) according to any of paragraphs B1 to B3, wherein an electric fan (26) is supported by a wing (62).

[0065] B5. An aircraft (12) according to any of paragraphs B1 to B4, wherein the turboshaft engine (20) is supported by the tail (14) of the fuselage (60).

[0066] B6. An aircraft (12) according to any of paragraphs B1 to B5, wherein the turboshaft engine (20) is supported by the wing (62).

[0067] B7. An aircraft (12) according to any of paragraphs B1 to B6, wherein the turbine generator (22), the condenser (76) of the hybrid propulsion system (10) and / or the mixer (68) of the hybrid propulsion system (10) are housed inside the turboshaft engine (20).

[0068] B8. An aircraft (12) according to any of paragraphs B1 to B7, wherein the electric motor (106) driving the electric fan (26) is housed in an electric fan compartment.

[0069] C1. A method (200) for providing thrust to an aircraft (12) via a hybrid propulsion system, the method (200) comprising: The first electric force (202) is generated by the turbine generator (22) of the liquid natural gas turbine shaft engine (20) operably connected to the aircraft (12); A second electric force (204) is generated via a liquid natural gas solid oxide fuel cell (24); and The electric fan (26) is powered (206) by a first electric force and / or a second electric force, thereby generating thrust for the aircraft (12) through the operation of the electric fan (26).

[0070] C2. According to the method (200) of paragraph C1, wherein the first electric force and the second electric force are supplied to the electric fan (26) substantially simultaneously.

[0071] C3. The method (200) according to any one of paragraphs C1-C2 also includes engine exhaust (74) from the turboshaft engine (20) via liquid natural gas cooling (208).

[0072] C3. The method (200) according to any of paragraphs C1-C3 also includes the liquefied natural gas from the fuel system (72) of the hybrid propulsion system (10) via exhaust preheating (210) from the low-pressure turbine (34).

[0073] C4.1. The method (200) according to any one of paragraphs C1-C4 further includes preheating (210) gaseous natural gas (82) via fuel cell exhaust (64) from the solid oxide fuel cell (24) and via a regenerator (78) of the hybrid propulsion system (10).

[0074] C5. The method (200) according to any of paragraphs C1-C4.1 further includes condensing (212) the liquid natural gas from the fuel system (72) of the hybrid propulsion system (10) and the engine exhaust (74) from the turboshaft engine (20).

[0075] C6. The method (200) according to any one of paragraphs C1-C5 further includes heat recovery (214) of gaseous natural gas (82) from the condenser (76) of the hybrid propulsion system (10) via fuel cell exhaust (64) from the solid oxide fuel cell (24).

[0076] C7. According to any one of the methods in paragraphs C1-C6 (200), it also includes: Water is extracted (220) from the exhaust of the turboshaft engine (20) and water vapor is generated; and Water vapor (218) is added to the natural gas from the fuel system (72) to provide humidified natural gas (88) to the anode (90) of the solid oxide fuel cell (24).

[0077] C8. The method (200) according to any one of paragraphs C1-C7 further includes pre-conditioning (224) of the reactants for the solid oxide fuel cell (24) via a low-pressure compressor (28) of a turboshaft engine (20).

[0078] C9. The method (200) according to any one of paragraphs C1-C8 further includes using bleed air (46) from the low-pressure compressor of the turboshaft engine (20) and exhaust gas from the solid oxide fuel cell (24) to pre-condition (224) the reactants of the solid oxide fuel cell (24).

[0079] C10. The method (200) according to any one of paragraphs C1-C9 further includes extracting (228) bleed air (46) from the low-pressure compressor (28) of the turboshaft engine (20) and providing the extracted bleed air (46) to the cathode (52) of the solid oxide fuel cell (24).

[0080] C11. The method (200) according to any one of paragraphs C1-C10 further includes controlling (226) one or more conditions for the fuel reactants of the solid oxide fuel cell (24) via a compressor and turbine pair (54), wherein the compressor (50) of the compressor and turbine pair (54) receives bleed air (46) from the low-pressure compressor (28) of the turbine shaft engine (20).

[0081] C12. The method (200) according to any one of paragraphs C1-C11 further includes extracting (228) energy from fuel cell exhaust (64) from solid oxide fuel cell (24) via a compressor and turbine pair (54) to regulate bleed gas (46) at the cathode (52) of solid oxide fuel cell (24).

[0082] C13. The method (200) according to any one of paragraphs C1-C12 further includes limiting (230) energy extraction from fuel cell exhaust (64) from the solid oxide fuel cell (24) via a compressor and turbine pair (54) to maintain the pressure of the exhaust from the solid oxide fuel cell (24), wherein the turbine (56) of the compressor and turbine pair (54) receives the fuel cell exhaust (64) from the cathode (52) of the solid oxide fuel cell (24).

[0083] C14. The method (200) according to any one of paragraphs C1-C13 further includes controlling (230) the pressure of the turbine exhaust (70) of the turbine (56) from the compressor and turbine pair (54) via a splitter (66) upstream of the turbine (56) and a mixer (68) downstream of the turbine (56).

[0084] C15. The method (200) according to any one of paragraphs C1-C14 further includes mixing (232) the exhaust gas from the solid oxide fuel cell (24) into the exhaust flow of the low-pressure turbine (34) leaving the turbine shaft engine (20) via a turbine shaft mixer (92) downstream of the regenerator (78), thereby increasing the power generated by the turbine generator (22).

[0085] C16. The method (200) according to any one of paragraphs C1-C15 further includes controlling (234) the ratio of electricity generated by the solid oxide fuel cell (24) to electricity generated by the turbine generator (22), wherein the control (234) is performed by the electric motor control system of the hybrid propulsion system (10).

[0086] C17. The method (200) according to any one of paragraphs C1-C16, wherein the method (200) is performed using the hybrid propulsion system (10) according to any one of paragraphs A1 to A16.

[0087] D1. The purpose of the hybrid propulsion system (10) according to any one of paragraphs A1 to A16 to provide thrust to the aircraft (12).

[0088] As used herein, the terms “adaptation” and “configuration” mean that an element, component, or other subject is designed and / or intended to perform a given function. Therefore, the use of the terms “adaptation” and “configuration” should not be construed as meaning that a given element, component, or other subject is simply “capable” of performing a given function, but rather that the element, component, and / or other subject is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing that function. Within the scope of this disclosure, elements, components, and / or other described subjects that are described as suitable for performing a particular function may also be additionally or alternatively described as being configured to perform that function, and vice versa. Similarly, subjects described as being configured to perform a particular function may be additionally or alternatively described as being operable to perform that function.

[0089] As used herein, the term “and / or” placed between the first entity and the second entity means (1) the first entity, (2) the second entity, and (3) one of the first entity and the second entity. Multiple entries listed with “and / or” should be interpreted in the same way, i.e., “one or more” entities are thus combined. Other entities may optionally exist, whether related to or unrelated to those specifically identified by the “and / or” clause. Thus, as a non-restrictive example, when used in conjunction with open-ended language such as “includes,” a reference to “A and / or B” may in one example refer only to A (optionally including entities other than B); in another example, only to B (optionally including entities other than A); and in yet another example, involving both A and B (optionally including other entities). These entities may refer to elements, actions, structures, steps, operations, values, etc.

[0090] The various disclosed elements and steps of the apparatuses and methods disclosed herein are not essential to all apparatuses and methods according to this disclosure, and this disclosure includes all novel and non-obvious combinations and sub-combinations of the various elements and steps disclosed herein. Furthermore, one or more of the various elements and steps disclosed herein may define independent inventive subject matter separate from and independent of the overall disclosed apparatus or method. Therefore, such inventive subject matter does not need to be associated with the specific apparatuses and methods explicitly disclosed herein, and such inventive subject matter may find application in apparatuses and / or methods not explicitly disclosed herein.

Claims

1. A hybrid propulsion system for an aircraft, the hybrid propulsion system comprising: Liquid natural gas turboshaft engine; A turbine generator, operatively connected to the turbine shaft engine; Liquid natural gas solid oxide fuel cells; as well as An electric fan is configured to generate thrust for the aircraft, wherein the electric fan is powered by the turbine generator and / or the solid oxide fuel cell.

2. The hybrid propulsion system of claim 1, wherein, The turbine generator and the solid oxide fuel cell simultaneously provide power to the electric fan.

3. The hybrid propulsion system of claim 1, further comprising: A fuel system configured to supply liquid natural gas to the turboshaft engine and the solid oxide fuel cell.

4. The hybrid propulsion system of claim 1, wherein, The turboshaft engine includes a low-pressure compressor configured to receive bleed air for the solid oxide fuel cell from a main inlet, the main inlet being configured to receive ambient air.

5. The hybrid propulsion system of claim 4, wherein, The low-pressure compressor is configured to pre-adjust the bleed gas for the solid oxide fuel cell by compressing the bleed gas, the compression pressurizing the bleed gas and raising its temperature, such that the bleed gas extracted from the low-pressure compressor is used as a source for the solid oxide fuel cell, and wherein the low-pressure compressor is configured to deliver the bleed gas to the solid oxide fuel cell.

6. The hybrid propulsion system of claim 4, further comprising: A compressor and turbine pair, wherein the compressor of the compressor and turbine pair is downstream of the low-pressure compressor of the turboshaft engine along the bleed air flow path, wherein the compressor of the compressor and turbine pair is upstream of the cathode of the solid oxide fuel cell, and wherein the turbine of the compressor and turbine pair is located downstream of the cathode of the solid oxide fuel cell, such that the turbine of the compressor and turbine pair is configured to receive fuel cell exhaust from the solid oxide fuel cell.

7. The hybrid propulsion system of claim 6, wherein, The compressor and turbine are configured to extract energy from the fuel cell exhaust gas from the solid oxide fuel cell to regulate the bleed gas at the cathode of the solid oxide fuel cell.

8. The hybrid propulsion system according to claim 6, further comprising: A shunt is located upstream of the turbine and downstream of the cathode of the solid oxide fuel cell; as well as A mixer, downstream of the turbine, wherein the mixer receives turbine exhaust from the turbine and fuel cell exhaust from the solid oxide fuel cell, and wherein the splitter and the mixer are configured to control the outlet pressure of the turbine exhaust gas leaving the turbine.

9. The hybrid propulsion system according to claim 1, wherein, The hybrid propulsion system is configured to use engine exhaust from the low-pressure turbine of the turboshaft engine to preheat liquid natural gas from the fuel system.

10. The hybrid propulsion system according to claim 1, further comprising: A condenser that receives liquid natural gas from a fuel system, wherein the condenser vaporizes the liquid natural gas to form gaseous natural gas, and wherein the condenser condenses liquid water from engine exhaust exiting the turbine shaft engine.

11. The hybrid propulsion system according to claim 10, further comprising: A regenerator downstream of the condenser receives fuel cell exhaust from the solid oxide fuel cell, and uses the heat from the fuel cell exhaust to further heat the gaseous natural gas from the condenser, and the regenerator supplies the gaseous natural gas from the condenser to the turbine shaft engine.

12. The hybrid propulsion system according to claim 11, further comprising: A water extractor configured to receive air from the condenser and liquid water in the air, wherein the water extractor is further configured to receive gaseous natural gas, and wherein the water extractor generates water vapor and mixes the water vapor with the gaseous natural gas to provide humidified natural gas to the anode of the solid oxide fuel cell.

13. The hybrid propulsion system according to claim 12, further comprising: Downstream of the regenerator is a turbine shaft mixer that mixes high-pressure fuel cell exhaust from the solid oxide fuel cell into the exhaust stream exiting the low-pressure turbine of the turbine shaft engine, thereby increasing the power generated by the turbine generator.

14. The hybrid propulsion system according to claim 1, wherein, The hybrid propulsion system is configured to reduce the transient response time of the electric fan by means of an operatively connected solid oxide fuel cell and a turboshaft engine.

15. The hybrid propulsion system according to claim 1, wherein, The hybrid propulsion system includes an electric motor controller configured to allocate a ratio of electrical load to the solid oxide fuel cell and the turbine generator, thereby determining a fuel consumption ratio of the solid oxide fuel cell and the turbine generator, wherein the fuel consumption ratio determines a fuel ratio of the amount of fuel allocated by the fuel system of the hybrid propulsion system to each of the turbine generator and the solid oxide fuel cell.

16. An aircraft comprising: body; Wings, which are supported by the fuselage; Turboshaft engine; as well as The hybrid propulsion system according to claim 1.

17. A method for providing thrust to an aircraft via a hybrid propulsion system, the method comprising: The first electrical force is generated via a turbine generator of a liquid natural gas turbine shaft engine operably connected to the aircraft; A second electrical force is generated via a liquid natural gas solid oxide fuel cell; as well as Power is supplied to the electric fan via the first and second electric forces, thereby generating thrust for the aircraft through the operation of the electric fan, wherein the first and second electric forces are supplied to the electric fan simultaneously.

18. The method of claim 17, further comprising: The exhaust gas from the turboshaft engine is cooled by liquefied natural gas from the fuel system of the hybrid propulsion system; The liquid natural gas from the fuel system is preheated via exhaust gas from the low-pressure turbine of the turboshaft engine; The liquid natural gas from the fuel system and the exhaust gas from the turboshaft engine are condensed. as well as The gaseous natural gas from the condenser of the hybrid propulsion system is reheated via fuel cell exhaust from the solid oxide fuel cell.

19. The method of claim 17, further comprising: Water is extracted from the exhaust of the turboshaft engine and water vapor is generated; as well as Water vapor is added to the natural gas from the fuel system of the hybrid propulsion system to provide humidified natural gas to the anode of the solid oxide fuel cell.

20. The method of claim 17, further comprising: Bleed air is extracted from the low-pressure compressor of the turboshaft engine and supplied to the cathode of the solid oxide fuel cell; One or more conditions of the fuel reactants in the solid oxide fuel cell are controlled by a compressor and a turbine, wherein the compressor in the compressor and turbine pair receives bleed air from the low-pressure compressor of the turbine shaft motor; as well as The exhaust gas from the solid oxide fuel cell is mixed into the exhaust stream of the low-pressure turbine leaving the turbine shaft engine via a turbine shaft mixer, thereby increasing the power generated by the turbine generator.

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