Vehicle with an energy conversion system

Abstract

A method for energy conversion of a vehicle is provided. The method includes: extracting a compressed fluid flow from a compressor section of a propulsion system; directing the compressed fluid flow to a turbine operably coupled to a drive shaft, wherein the drive shaft is operably coupled to a load device; expanding the compressed fluid flow passing through the turbine to generate an output torque at the drive shaft to operate the load device; and flowing the expanded compressed fluid flow from the turbine to be in thermal communication with a thermal load.

Description

Technical Field

[0001] The present subject matter generally relates to energy conversion systems and thermal management systems for propulsion systems and vehicles. The present subject matter relates to thermal management and energy conversion systems for aircraft and propulsion systems. Background Art

[0002] Propulsion systems, such as gas turbine engines, face challenges in the thermal management of increasingly high thermal loads. The increasingly high thermal loads are due to the increasing electrification of propulsion systems and vehicles, such as aircraft, more electrical loads, and the need for increased thermal efficiency in fuel systems, oil systems, and coolant systems. Traditional systems can use airflows to provide thermal attenuation of fuel or lubricants. However, such configurations may cause fan flow blockage, thereby reducing engine performance and efficiency. Traditional configurations may also be insufficient to attenuate the thermal loads associated with reduction gearboxes, variable pitch fans, increased electrification, or third stream bypass engines. Therefore, there is a need for improved energy conversion systems and thermal management systems for propulsion systems and vehicles. Summary of the Invention

[0003] Aspects and advantages of the present invention will be set forth in part in the following description, or may be obvious from the description, or may be learned by practice of the present invention.

[0004] One aspect of the present disclosure relates to a method for energy conversion of a vehicle. The method includes: extracting a compressed fluid flow from a compressor section of a propulsion system; directing the compressed fluid flow to a turbine operably coupled to a drive shaft, where the drive shaft is operably coupled to a load device; expanding the compressed fluid flow passing through the turbine to generate an output torque at the drive shaft to operate the load device; and directing the expanded compressed fluid flow from the turbine to be in thermal communication with a thermal load.

[0005] Another aspect of the present disclosure relates to a vehicle including a propulsion system, an energy conversion system, and a load device. The propulsion system includes a fan section, a compressor section, a heat addition system, an expansion section, and an exhaust section in a serial flow arrangement. A core flow path is formed through the compressor section, the heat addition system, and the expansion section. A fan bypass flow is configured to bypass the core flow path, and a third flow path is configured to bypass the heat addition system. The energy conversion system includes a fluid circuit forming a serial fluid communication of an oxidizer flow from the compressor section to the turbine. The fluid circuit provides a serial fluid communication from the turbine to the thermal load, and the oxidizer flow at the thermal load is in thermal communication with the fluid flow at the thermal load. The load device is operably coupled to the turbine by a drive shaft. The turbine and the drive shaft are configured to generate an output torque at the load device via the expansion of the oxidizer flow at the turbine.

[0006] These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] A complete and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art, is set forth in the specification, which makes reference to the accompanying drawings, in which:

[0008] Figure 1 is an exemplary embodiment of a vehicle including a propulsion system and an energy conversion system in accordance with aspects of the present disclosure;

[0009] Figures 2-8 is a schematic embodiment of a propulsion system and an energy conversion system in accordance with aspects of the present disclosure;

[0010] Figure 9 is a schematic flow chart outlining a method for operating a propulsion system and an energy conversion system; and

[0011] Figures 10A-10B is a schematic flow chart outlining steps of a method for operating a propulsion system and an energy conversion system.

[0012] Reference numerals that are repeated in this specification and the drawings are intended to represent the same or similar features or elements of the present invention. DETAILED DESCRIPTION

[0013] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, and not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For example, features shown or described as part of one embodiment can be used with another embodiment to yield yet another embodiment. Accordingly, the present invention is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0014] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to denote the position or importance of the individual components.

[0015] The terms “upstream” and “downstream” refer to the relative direction with respect to the flow of fluid in a fluid path. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction towards which the fluid flows.

[0016] Embodiments of a propulsion system, a vehicle, and an energy conversion system are provided that can improve overall system and vehicle efficiency, for example, by utilizing relatively high-pressure fluid from a compressor section of the propulsion system rather than using a pressure regulator or releasing the fluid to, for example, atmospheric conditions. Thus, the work extracted from the air removed from the propulsion system can be maximized. Embodiments provided herein can further improve heat transfer from the lubricant in a lubricant system. Still further, embodiments provided herein can improve heat transfer from the lubricant and additionally from one or more load devices (such as a computing system, an environmental control system, an avionics system, or an electric machine). Additionally or alternatively, the cooling fluid at the fluid circuit can be adjusted independently, for example, via a flow control device and / or a flow device, relative to the operating conditions at the propulsion system. Embodiments provided herein can include specific serial or parallel flows and components to advantageously improve heat transfer and overall system efficiency. Certain embodiments can allow substantially independent adjustability of the heat exchange fluid relative to the propulsion system operating conditions, the lubricant system operating conditions, or the load system operating conditions.

[0017] Referring now to the drawings, in Figure 1 an exemplary embodiment of a vehicle 100 including a propulsion system 10 and an energy conversion system 200 according to aspects of the present disclosure is provided. In an embodiment, the vehicle 100 is an aircraft including an aircraft structure or airframe 105. The airframe 105 includes a fuselage 110 to which wings 120 and a tail 130 are attached. A propulsion system 10 according to aspects of the present disclosure is attached to one or more portions of the airframe. In various embodiments, the energy conversion system 200 is a system configured to desirably distribute a heat load to add or remove heat from one or more fluids or structures (such as, but not limited to, an oxidizer, fuel, lubricant, hydraulic fluid, pneumatic fluid, or cooling fluid for an electric machine, an electronic device, a computing system, an environmental control system, a gear assembly, or other systems or structures at the propulsion system).

[0018] In some cases, the propulsion system 10 is attached to the rear of the fuselage 110. In some other cases, the propulsion system 10 is attached below, above, or through a portion of the wing 120 and / or the tail 130. In various embodiments, the propulsion system 10 is attached to the airframe 105 via a pylon or other mounting structure. In still other embodiments, the propulsion system 10 is housed within the airframe, as can be exemplified in certain supersonic military or commercial aircraft.

[0019] Various embodiments of vehicle 100 include a computing system 140, such as an avionics or other electronic or computing device configured to control vehicle 100 or propulsion system 10. Vehicle 100 may further include, for example, an environmental control system (ECS) 150 that provides thermally conditioned air to the vehicle's cockpit, computing system 140, vehicle surface anti-icing system 160, propulsion system anti-icing system, or other systems of vehicle 100 or propulsion system 10. In various embodiments such as those described herein, energy conversion system 200 may be configured to provide a thermally conditioned fluid to one or more of the systems described herein.

[0020] Now referring to Figures 2-4 , exemplary schematic embodiments of propulsion system 10 and energy conversion system 200 are provided. Propulsion system 10 may generally be configured as a Brayton cycle machine. Particular embodiments of propulsion system 10 may be configured as a turbine, ramjet, or scramjet. Other particular embodiments of propulsion system 10 may include a turbine configured as a turbofan engine, turboprop engine, turbojet engine, turboshaft engine, propeller engine, or open rotor engine. In Figures 2-4 , propulsion system 10 is configured as a three-stream engine that includes a fan bypass flow 14, a core flow path 70, and a core bypass or third stream 71. Certain embodiments of propulsion system 10 include a fan section 12, a compressor section 20, a heat addition or combustion section 26, an expansion section 30, and an exhaust section 36 in a serial flow arrangement. In various embodiments, heat addition system 26 may be configured as a deflagration combustion system or a detonation combustion system. Heat addition system 26 may include any suitable type of system for receiving a liquid and / or gaseous fuel stream and generating hot gases, including but not limited to annular, cannular, can, vortex, swirl, or vortex, rotating detonation, pulse detonation, subsonic, or supersonic combustion systems. Fan section 12 includes one or more stages of rotors and blades 121. Certain embodiments also include one or more stages of stators that are stationary relative to the central axis of propulsion system 10.

[0021] The compressor section 20, the heat addition system 26, and the expansion section 30 are typically positioned in a serial aerodynamic flow arrangement. The compressor section 20, the heat addition system 26, and the expansion section 30 can together define the core engine or gas generator of the propulsion system 10. In some embodiments, such as those described herein, the compressor section 20 includes a high-pressure compressor 22 that is positioned in a direct serial flow arrangement with the heat addition system 26 and the high-pressure turbine 32 of the expansion section 30. The low-pressure turbine 34 of the expansion section 30 can be operatively coupled to the fan section 12 to drive one or more stages of the fan section 12. In some embodiments, the propulsion system 10 can include a medium-pressure compressor or a low-pressure compressor 24 that is aerodynamically positioned between the fan section 12 and the high-pressure compressor 22. In further embodiments, a medium-pressure turbine can be aerodynamically positioned between the high-pressure turbine 32 and the low-pressure turbine 34.

[0022] The core flow path 70 extends at least through the high-pressure compressor 22, the heat addition system 26, and the high-pressure turbine 32. The core bypass or third flow path 71 extends downstream of the medium-pressure or low-pressure compressor 24 and bypasses the core flow path 70 at the high-pressure compressor 22. In some embodiments, the third flow path 71 extends into fluid communication downstream of the fan bypass flow 14 at the blade 122.

[0023] The third flow path 71 is an air flow that is configured to recover fluid energy to produce a portion of the total thrust of the propulsion system 10. During operation, the pressure ratio of the third flow path 71 is higher than the pressure ratio at the fan bypass flow 14. In one embodiment, the portion of the total thrust produced by the third flow path 71 can include a dedicated exhaust nozzle at the outlet end. In another embodiment, the portion of the total thrust produced by the third flow path 71 can be mixed with the fan bypass flow 14. In yet another embodiment, the portion of the total thrust produced by the third flow path 71 can be mixed with the core flow path 70 downstream of the heat addition system 26 and discharged through the exhaust section 36. Various embodiments of the third flow path 71 are configured to produce less than 50% of the total thrust of the propulsion system 10. In some embodiments, during operation, the third flow path 71 is configured to produce 2% or more of the total thrust of the propulsion system 10. In embodiments, the propulsion system 10 is configured to produce 2% or more and up to 50% of the total thrust under takeoff conditions, full load conditions, or rated takeoff power conditions. Exemplary rated takeoff power conditions can be related to sea level static flight at an ambient temperature operating condition of 86 degrees Fahrenheit.

[0024] In some embodiments, the operating temperature of the air passing through the third flow path 71 is lower than the maximum compressor discharge temperature of the propulsion system 10. In certain embodiments, the operating temperature of the air passing through the third flow path 71 is lower than approximately 350 degrees Fahrenheit. In another embodiment, the operating temperature of the air passing through the third flow path 71 is lower than approximately 250 degrees Fahrenheit. In yet another embodiment, the operating temperature of the air passing through the third flow path 71 is lower than approximately 200 degrees Fahrenheit. In various embodiments, the operating temperature of the air passing through the third flow path 71 is at least the ambient temperature, or at least the temperature of the air entering the compressor section. It should be understood that the operating temperature range through the third flow path 71 may permit heat transfer to or from the third flow path 71 and another flow path (e.g., the fan bypass flow path 14 or the core flow path 70).

[0025] Those skilled in the art will understand that the third flow path 71 extends from the core flow path 70 upstream of the heat addition system 26. In some embodiments, the third flow path 71 extends downstream of the fan section 12. In still various embodiments, the third flow path 71 is configured to allow air flow to exit the propulsion system 10 to generate, for example, a portion of the total thrust of the propulsion system 10 as described herein.

[0026] In addition, those skilled in the art will understand that the third flow path 71 is at least partially different from the discharge loop or other flow paths via the discharge of air as propulsion thrust. The fan bypass flow path 14, the third flow path 71, and the core flow path 70 may each include an exhaust nozzle structure. Such structures may include variable area structures, fixed area structures, converging-diverging nozzles, thrust vector structures, lobed exhaust mixers, or other suitable exhaust structures. The propulsion system 10 may be configured to passively adjust the thrust output from the third flow path 71. In some embodiments, the propulsion system 10 may be configured to actively adjust the thrust output from the third flow path 71, for example, generally by adjusting fuel flow, motor load, variable stators, variable inlet guide vanes, variable exhaust area or geometry, or fluid characteristics, and based on the desired performance relative to the operating conditions.

[0027] Still referring to Figures 2-4, the energy conversion system 200 includes a first heat exchanger 205 positioned in thermal communication with a third fluid flow path 71. The energy conversion system 200 includes a wall conduit forming a fluid circuit 210, such as a duct, manifold, or other suitable structure configured to generally extract air or oxidant from the core flow path 70 and cause the air or oxidant to flow. In various embodiments, the air flow schematically depicted by arrow 201 is extracted from one or more stages of the high-pressure compressor 22 or from unburned air at the heat addition system 26 downstream of the high-pressure compressor 22.

[0028] The energy conversion system 200 includes a flow control device 220 positioned at the fluid circuit 210 downstream of the compressor section 20. A turbine 230 is positioned at the fluid circuit 210 downstream of the compressor section 20. In a particular embodiment, the flow control device 220 and the turbine 230 are integrated as a variable area turbine nozzle (VATN). The flow control device 220 and the turbine 230 together defining the VATN are configured to control the mass flow into or through the turbine 230. In one embodiment, the first control valve 220 is a variable area structure at the inlet of the turbine 230, such as a variable area nozzle. However, in other embodiments, the first control valve 220 is a separate flow control structure configured to adjust the mass flow through the turbine 230. In certain embodiments, the turbine 230 is downstream of the flow control device 220.

[0029] A drive shaft 231 is operably coupled to the turbine 230 to drive a load device 270. In various embodiments, the load device 270 includes one or more of an electric motor, a mechanical drive, or a fluid flow device. For example, the load device 270 may form an accessory gearbox, a reduction gear assembly, a fan pitch assembly, or a main gearbox assembly. The load device 270 is operably coupled to the propulsion system 10, such as a shaft, or particularly a high-speed shaft connecting the high-pressure compressor 22 and the high-pressure turbine 32. The load device 270 may include one or more fuel pumps, electric motors (e.g., electric motors and / or generators, constant frequency or variable frequency machines, hybrid systems, etc.), lubricant pumps, hydraulic pumps, air compressors, engine starters, sensor drivers, and auxiliary gearbox drivers, or combinations thereof. The fluid expansion at the turbine 230 provides at least part of the energy to drive the load device 270.

[0030] Still referring to Figures 2-4, the energy conversion system 200 includes a heat load 250 that is positioned in thermal communication with an air flow through the fluid circuit 210 downstream of the turbine 230. In various embodiments, the heat load 250 forms a heat exchanger configured to form an air-cooled oil cooler (ACOC), a fuel-cooled oil cooler (FCOC), or other heat exchanger configured to cool a fluid directly or indirectly based on the cooled air flow discharged from the turbine 230. In one embodiment, the heat load 250 is configured to remove heat or thermal energy from a lubricant or oil-based fluid, a lubricant system of the propulsion system 10, a gearbox cooling fluid, a propeller control mechanism cooling fluid, a motor coolant, or other fluid from the propulsion system 10 or the vehicle 100 having heat or thermal energy that is desired to be released to the cooled air flow discharged from the turbine 230, or to receive heat or thermal energy.

[0031] Reference Figures 2-4 , certain embodiments of the system 200 include a serial flow arrangement of an air flow from the compressor section 20 that is in thermal communication with a first heat exchanger 205, which is positioned in thermal communication at a third flow path 71. The flow system 200 may also include a flow control device 220 that is positioned in a serial flow arrangement between the compressor section 20 and the first heat exchanger 205. The air flow 201 is extracted from the compressor section 20 (e.g., from the core flow path 70). The flow is adjusted via the flow control device 220. The air flow from the flow control device 220 (schematically depicted via arrow 211) is provided in thermal communication to the first heat exchanger 205. The initially cooled air flow, schematically depicted via arrow 211a, is provided to the turbine 230.

[0032] The remaining heat or thermal energy in the air flow 211a from the first heat exchanger 205 is used to drive the load device 270 or otherwise provide energy to the load device 270. The expanded and cooled air flow exiting the turbine 230 (e.g., schematically depicted via arrow 211b) is provided in thermal communication with the heat load 250. The cooled air flow 211b receives thermal energy from the heat load 250 as described above. The additionally cooled air flow, schematically depicted via arrow 211c, is discharged from the system. In some embodiments, the air flow 211c is dumped or provided downstream of the first heat exchanger 205 at the third flow path 71. In another embodiment, the air flow 211c is provided downstream of the blade 122 at the fan flow 14. In still other embodiments, the air flow may be discharged into the core flow path, the third flow path, or the fan bypass flow path.

[0033] Reference Figure 2, the thermal load 250 can specifically form a heat exchanger configured to directly cool a fluid or otherwise receive heat or thermal energy from another fluid. In certain embodiments, the thermal load 250 forms an air-cooled fluid cooler.

[0034] Reference Figure 3 , in one embodiment, the thermal load is configured as an air-fluid heat exchanger 250a. The fuel system 300 for the propulsion system 10 or the vehicle 100 includes a fuel flow device 275 configured to provide a liquid and / or gaseous fuel flow in thermal communication with the cooled air stream 211b via the air-fluid heat exchanger 250a, schematically depicted by arrow 276. The initially heated fuel flow that has received heat or thermal energy from the air stream 211a (schematically depicted by arrow 276a) is provided to the thermal load via a fuel circuit. The thermal load forms a fuel-fluid heat exchanger 250b configured to receive or remove heat or thermal energy from one or more systems in order to provide cooling for one or more fluids as described above.

[0035] In certain embodiments, the heated fuel flow schematically depicted by arrow 276b is provided to the heat addition system 26 and burned. The heated fuel can provide desired physical properties to the fuel to improve the combustion performance of the propulsion system 10. The heated fuel flow 276b can produce a desired temperature, viscosity, or other properties that improve atomization, fuel-oxidizer mixing at the heat addition system, and other combustion factors. The desired physical properties of the heated fuel flow can improve combustion performance, for example, by reducing smoke, improving blowout performance, reducing emissions (e.g., oxides of nitrogen, carbon monoxide, carbon dioxide, unburned hydrocarbons, etc.), or increasing the re-illumination altitude.

[0036] In a particular embodiment, the heated fuel flow schematically depicted by arrow 276b is provided to a deoxygenator 277 configured to remove oxygen from the fuel flow 276b. In still further particular embodiments, the heated deoxygenated fuel flow schematically depicted by arrow 276c is provided to a heater 279 configured to provide heat or thermal energy to the fuel flow 276c. In various embodiments, the heater 279 is a heat exchanger or other suitable mechanism for heating a liquid and / or gaseous fuel. In a particular embodiment, the heater 279 is a non-polluting fluid heater configured to provide heat or thermal energy to the fuel flow without oxidizing the fuel. In such an embodiment, the heated deoxygenated fuel flow schematically depicted by arrow 276d is provided to the heat addition system 26 for combustion or detonation. In other embodiments, additionally or alternatively, the fuel flow 276d can be generally provided to, for example, an inter-turbine combustor, afterburner, or reheat device located downstream of the heat addition system 26.

[0037] Now referring to Figure 4 , the propulsion system 10 and the vehicle 100 can be configured as described, for example, with respect to Figure 3 . In Figure 4 , the fuel system 300 further includes a fuel distribution device 271 configured to adjust the proportion of the mixed fuel to a desired temperature or other physical properties. The fuel distribution device 271 receives a fuel stream 276 from the fuel flow device 275. A first flow control device 267 (such as a valve or other suitable mechanism) supplies a first portion of the fuel stream (schematically depicted via arrow 276e) to the air-fluid heat exchanger 250a, as described, for example, with respect to Figure 3 . The initially heated fuel stream, schematically depicted via arrow 276f, is supplied to the fuel reservoir 273 where the initially heated fuel stream is mixed with the unheated (e.g., cold) fuel at the fuel reservoir 273. The mixed fuel is supplied to a second flow control device 269 at the fuel distribution device 271, for example, depicted via arrow 276g. During operation, the first flow control device 267 adjusts the proportion of the fuel directed to the air-fluid heat exchanger 250a and a portion of the fuel that bypasses the air-fluid heat exchanger 250a and is directed to the second flow control device 269 (schematically depicted via arrow 276h, for example).

[0038] Still referring to Figure 4 , the second flow control device 269 can direct a portion of the fuel stream directly back to the fuel reservoir 273, schematically depicted via arrow 276i, for example. Thus, a fuel return loop or circuit is provided where a portion of the fuel heated by the air-fluid heat exchanger 250a is mixed with the fuel located in the fuel reservoir 273. The fuel return loop can increase and maintain the desired minimum temperature of the fuel. The desired minimum temperature of the fuel can be at least partially based on the heat load provided by other heat exchangers described herein. In various embodiments, the fuel return loop and the fuel distribution device 271 are positioned upstream along the fluid circuit 210 with respect to the fuel-fluid heat exchanger 250b and the heater 279 described with respect to Figure 3 .

[0039] In various embodiments, the waste heat recovery (WHR) system 400 is positioned downstream along the fluid circuit 210 of the air-fluid heat exchanger 250a. In a particular embodiment, the WHR system 400 is positioned downstream along the fluid circuit 210 of the fuel distribution device 271. In various embodiments, the WHR system 400 includes a first WHR heat exchanger 410 positioned in parallel with the fuel-fluid heat exchanger 250b. The first WHR heat exchanger 410 is configured to remove heat from the WHR bus fluid.

[0040] In various embodiments, the WHR bus fluid is a lubricant (e.g., oil, oil-based fluid, synthetic oil, polyalphaolefin, polyalphaolefin-based fluid, etc., or combinations thereof), a liquid and / or gaseous fuel (e.g., hydrocarbon fuel, fuel oil, aviation turbine fuel, or other suitable propulsion system fuel), a supercritical fluid (e.g., supercritical carbon dioxide, water, methane, ethane, propane, ethylene, propylene, methanol, ethanol, acetone, nitrous oxide, or other suitable substances having a temperature and pressure above the endpoints of their phase equilibrium curves), a siloxane or siloxane-based heat transfer fluid (e.g., polydimethylsiloxane-based fluid such as Syltherm TM or a similar fluid), or other suitable heat transfer fluids.

[0041] The first WHR heat exchanger 410 can be configured to cool the WHR bus fluid to a substantially starting temperature upstream of the fluid flow device 420. The cooled fluid allows for maintaining a sufficient temperature difference between the WHR bus fluid and the exhaust combustion gases, e.g., for steady-state heat transfer. A portion of the fuel flow, schematically depicted by arrow 276j, is provided from the fuel distribution device 271 to the first WHR heat exchanger 410. The fuel flow 276j is provided in thermal communication with the heat transfer fluid flowing within the WHR loop 405. The heat transfer fluid can be any desired fluid suitable for receiving and transferring heat or thermal energy, such as described with respect to the WHR system 400. In a particular embodiment, the WHR loop 405 is a closed-loop system, and the heat transfer fluid flowing through the closed-loop system is in thermal communication with the fuel and exhaust gases from, e.g., the propulsion system 30 described herein.

[0042] The WHR system 400 includes a fluid flow device 420 configured to pump or otherwise cause the heat transfer fluid to flow through the WHR loop 405. Although Figure 4 the first WHR heat exchanger 410 is depicted as providing a heat transfer fluid flow 401 to the fluid flow device 420, the fluid flow device 420 can be located at any operable location within the WHR loop 405. A pressurized heat transfer fluid flow, schematically depicted by arrow 401a, is provided to the second WHR heat exchanger 430. In some embodiments, the second WHR heat exchanger 430 is a heater device located at the exhaust section 36 or the expansion section 30 of the propulsion system 10. The second WHR heat exchanger 430 can be configured to receive heat or thermal energy from the exhaust gases leaving the propulsion system 10 (e.g., via arrow 65).

[0043] In certain embodiments, the WHR system 400 includes a third WHR heat exchanger 440 positioned in thermal communication with a bleed oxidizer stream (e.g., depicted via arrow 67) withdrawn from the compressor section 20 for thermal management at the expansion section 30. In a particular embodiment, the bleed oxidizer stream 67 is cooling air (CCA) for cooling at the high-pressure turbine 32 or the low-pressure turbine 34. In various embodiments, the CCA is specifically cooled below the temperature of the air when withdrawn or otherwise removed from the compressor section 20. Additionally or alternatively, the bleed oxidizer stream 67 is generally used for cooling at the expansion section (e.g., at the blades, shrouds, vanes, or bearings, or other desired components). In yet a particular embodiment, the bleed oxidizer stream 67 can be used to provide cooling for the turbine rotor blades at the expansion section 30. A heat transfer fluid stream (schematically depicted via arrow 401b) heated by the second WHR heat exchanger 430 is provided to the third WHR heat exchanger 440. The heat transfer fluid stream 401b, although having received heat from the second WHR heat exchanger 430, is relatively cooler than the bleed oxidizer stream 67 received from the compressor section 20. Thus, heat or thermal energy from the bleed oxidizer stream 67 is provided to the heat transfer fluid via the third WHR heat exchanger 440.

[0044] The heated heat transfer fluid stream from the third WHR heat exchanger 440 (schematically depicted via arrow 401c) is provided to a heater 279 in thermal communication with a fuel stream 276c downstream of the fuel-fluid heat exchanger 250b. In a particular embodiment, a valve or other flow control device 255 receives the heated fuel stream after receiving thermal communication from the first WHR heat exchanger 410, e.g., schematically depicted via arrow 276k. The flow control device 255 is configured to desirably combine the fuel stream 276b with the fuel stream 276k to output a heated fuel stream having desired thermal or physical properties, schematically depicted via arrow 276bb. In various embodiments, the fuel stream 276bb is provided to the heat addition system 26 for combustion or detonation. In certain embodiments, the fuel stream 276bb is provided together with the fuel stream 276b to, for example, the deoxidizer 277 described with respect to Figure 3 In a particular embodiment, the fuel stream is provided in thermal communication to receive heat or thermal energy from the heat transfer fluid at the WHR loop 405 via the first WHR heat exchanger 410 and the heater 279.

[0045] Embodiments of the propulsion system 10 and vehicle 100 that include the energy conversion system 200, fuel system 300, and / or WHR system 400 provided herein may provide improved overall propulsion system and vehicle efficiency through improved systems, structures, or methods for, e.g., thermal management and energy conversion provided herein. Embodiments provided herein include specific positioning, placement, and serial fluid flows configured to improve overall system performance. One or more elements of the system, such as but not limited to heat exchangers, loops, conduits, flow devices, or turbines provided herein, may be produced via one or more of the additive manufacturing methods described below. Further, such systems may not be possible without the flow paths, conduits, loops, structures, or other details permitted by additive manufacturing methods. Additionally, certain arrangements provided herein may produce beneficial and unexpected results via the transfer of heat or thermal energy to various fluids or serial flows such as those provided herein at specific junctions.

[0046] Now referring Figures 5-8 , various schematic embodiments of the propulsion system 10 and energy conversion system 200 are provided herein. Embodiments provided herein may be configured to be substantially similar to those described with respect to Figures 2-4 . In certain embodiments, the flow device 240 is positioned at the fluid loop 210 downstream of the flow control device 220 and the turbine 230. The flow control device 220 is configured to provide a first portion 211 of the fluid to the turbine 230 while providing a second portion 212 of the fluid from the flow control device 220 to the flow device 240. The flow device 240 is configured to combine, mix, or draw together the flows from the first portion 21 and the second portion 212. In various embodiments, the flow device 240 is a fluid mixer, injector, or other suitable device configured to allow the relatively higher pressure fluid flow at the second portion 212 to draw together the relatively lower pressure flow from the first portion 211 via the fluid loop 210 as a combined fluid flow schematically depicted at 213. The fluid loop 210 is configured to provide the first portion 211 of the fluid from the turbine 230 to the flow device 240. The heat load 250 is positioned in thermal communication with the fluid loop 210 downstream of the turbine 230.

[0047] In various embodiments, the flow control device 220 is a diverter valve or other suitable mechanism configured to direct the ratio or proportion of the first portion 211 and the second portion 212 to the turbine 230 and the flow device 240, respectively. The pressurized fluid flow from the compressor section 20 is used to drive the turbine 230, as depicted at the first portion 211, for example. In certain embodiments, the expanded and decompressed fluid, schematically depicted at 211a, then travels from the turbine 230 to the flow device 240 along the fluid circuit 210. In yet other embodiments, the expanded and decompressed fluid 211a travels from the turbine 230 along the fluid circuit 210 to be in thermal communication with the heat load 250. After being in thermal communication with the heat load 250, the fluid, schematically depicted via arrow 211b, can be provided to the flow device 240, such as Figure 3 as depicted in. In another embodiment, the fluid 211b can be discharged or dumped, for example, into the engine compartment, under the engine cowling, or to the atmosphere, such as Figure 5 as depicted in. The flow device 240 is configured to receive the first portion 211 of the fluid from the flow control device 220 and the second portion 212 of the fluid from the turbine 230. In certain embodiments, the flow control device 220 is configured to provide the first portion 211 of the fluid to the turbine 230 while providing the second portion 212 of the fluid to the flow device 240, with the second portion 212 of the fluid bypassing the turbine 230.

[0048] It should be understood that traditional thermal management systems typically utilize valves to restrict or regulate the flow from an engine compressor to an air cycle machine compressor. Such systems typically result in a relatively large pressure loss across the valve. This pressure loss causes significant inefficiencies in the engine and the energy conversion system by compressing air at the engine compressor and then releasing excessive pressure to control or regulate the flow to the air cycle machine compressor. In contrast, embodiments of the present disclosure utilize the excessive pressure at the turbine 230 to perform useful work, such as via a drive shaft 231 coupled to the turbine 230 and the load device 270, as provided herein.

[0049] The first portion 211 of the fluid can generally include a first fluid characteristic that is different from the second portion 212 of the fluid having a second fluid characteristic. In various embodiments, the first fluid characteristic includes a higher fluid pressure or flow rate than the second fluid characteristic. The flow device 240 is configured to receive the respective portions 211, 212 of the fluid and provide a desired fluid (e.g., having a third fluid characteristic depicted at the fluid 213 in the fluid circuit 210, which is different from the first fluid characteristic of the fluid 211 and the second fluid characteristic of the fluid 212) downstream along the fluid circuit 210.

[0050] Reference Figures 5-6, in various embodiments, the turbine 230 is operatively coupled to a turbine 260 positioned at the fluid circuit 210. The turbine 260 includes a compressor 262 coupled to a turbine 266 via a drive shaft 264. In certain embodiments, the turbine 260 is part of an air cycle system. Embodiments of the turbine 260 may include an air cycle machine, a vapor compression system, or a bootstrap system, or further include an electric machine (e.g., a motor and / or a generator) or other suitable devices as described herein. In certain embodiments, the turbine 260 is a multi-stage system having multiple compressor stages and / or multiple turbine stages. However, in other embodiments, the turbine 260 may be configured as a single-stage compressor and / or a single-stage turbine. The compressor 262 is positioned at the fluid circuit 210 downstream of the flow device 240. In certain embodiments, the turbine 230 is operatively coupled to the drive shaft 264 to provide energy to drive the compressor 262. In still certain other embodiments, the turbine 230 and the turbine 266 of the turbine 260 together provide energy to drive the compressor 262.

[0051] It should be understood that the flow control device 220 allows the fluid circuit 210 to selectively modulate the ratio or proportion of the first portion 211 and the second portion 212 to the turbine 230 and the second control valve 240, respectively. Compared with a pressure regulator configured to reduce pressure and cause work or energy loss of the propulsion system 10 and the energy conversion system 200, the flow control device 220, such as a defined diverter valve or other suitable device for selectively modulating the proportion of the fluid flow to two or more circuits (e.g., the first portion 211 and the second portion 212), allows the turbine 230 to utilize the relatively high-pressure fluid from the compressor section 20 to at least partially drive the turbine 260 or the load device 270. The turbine 230 may correspond to the desired fluid characteristics (e.g., the desired second fluid characteristics) of the fluid flowing out of the turbine 230 to the flow device 240. Additionally or alternatively, the turbine 230 may correspond to the desired energy output of the turbine 260 or the load device 270 to which the turbine 230 is operatively coupled.

[0052] Now refer to Figures 2-5, in various embodiments, the vehicle 100, the propulsion system 10, and the energy conversion system 200 include a heat exchanger 310 located at the fluid circuit 210 downstream of the compressor 262 and upstream of the turbine 266 of the turbine 260. In various embodiments, the heat exchanger 310 is positioned in thermal communication with one or more fan flows (such as the fan bypass 14 or the third flow path 71) of the propulsion system 10. The heat exchanger 310 is configured to discharge thermal energy or heat from the fluid circuit 210. In certain embodiments, the heat exchanger 310 is configured to input thermal energy or heat into the fuel circuit, for example, to heat the fuel flow before injecting the fuel into the heat addition or combustion section. In still other embodiments, the heat exchanger 310 is configured to input thermal energy or heat into the air flow passing through one or more fan flows 14. In various embodiments, the heat exchanger 310 includes a fuel circuit positioned in thermal communication with the fluid circuit 210.

[0053] In certain embodiments, the vehicle 100, the propulsion system 10, and the energy conversion system 200 include a heat exchanger 315, which is located at the fluid circuit 210 downstream of the compressor section 20 and upstream of the flow control device 220. In various embodiments, the heat exchanger 315 is positioned in thermal communication with one or more fan flows 14 of the propulsion system 10, as described herein. The heat exchanger 315 is configured to discharge thermal energy or heat from the fluid circuit 210. In certain embodiments, the heat exchanger 315 is configured to input thermal energy or heat into the fluid flow passing through one or more fan flows 14. In a particular embodiment, the heat exchanger 315 is a pre-cooler located at the fluid circuit 210 to remove thermal energy or heat from the fluid before supplying the fluid to the flow control device 220 and the turbine 230. It should be understood that various embodiments of the system may include a heat exchanger 315 defining a pre-cooler, which is located at the fluid circuit 210 upstream of the flow control device 220.

[0054] Brief reference Figures 7-8 , in certain embodiments, the energy conversion system 200 may include a valve 280, which is located at the fluid circuit 210 downstream of the heat exchanger 315 and upstream of the flow control device 220. The valve 280 is configured to supply a portion of the fluid to the expansion section 30 and a portion of the fluid to the flow control device 220, as described herein. The fluid flow from the heat exchanger 315 to the valve 280 and the expansion section 30 may define a turbine cooling flow, an active clearance control (ACC) fluid, or other cooling or pneumatic fluids for the propulsion system 10.

[0055] In such as Figures 5-8In the various embodiments shown, the thermal load 250 includes a lubricant heat exchanger 320 positioned at the fluid circuit 210 downstream of the turbine 230. In various embodiments, the thermal load 250 includes a lubricant circuit 251 positioned in thermal communication with the fluid circuit 210. The lubricant circuit 251 includes oil or an oil-based fluid from the lubricant system 252. The lubricant system 252 can include any suitable system that includes pumps, scavenging devices, and heat exchangers that are configured to provide lubricant to one or more bearing assemblies, gear assemblies, actuators, or other systems of the propulsion system 10 or the vehicle 100. The lubricant circuit 251 is arranged to be in a heat exchanger relationship with the fluid circuit 210 at the lubricant heat exchanger 320.

[0056] In certain embodiments, the lubricant heat exchanger 320 is configured to receive or remove heat or thermal energy from the lubricant circuit 251 and provide the heat or thermal energy to the fluid circuit 210, or more particularly, a first portion 211 of the fluid downstream of the turbine 230. The flow control device 220 can be configured to adjust the amount of the first portion 211 of the fluid provided to the turbine 230 and the thermal load 250 based on a desired heat transfer between the fluid circuit 210 and the lubricant circuit 251.

[0057] In certain embodiments, the thermal load 250 is positioned in thermal communication with the fluid circuit 210 downstream of the turbine 230. In a particular embodiment, the thermal load 250 including the lubricant system 252 is positioned in thermal communication with the fluid circuit 210 downstream of the turbine 230. In a more specific embodiment, as Figures 2-5 shown, the thermal load 250 including the lubricant system 252 is positioned in thermal communication with the fluid circuit 210 downstream of the turbine 230 and upstream of the flow device 240. In other embodiments, as Figures 7-8 shown, the thermal load 250 including the lubricant system 252 is positioned in thermal communication with the fluid circuit 210 downstream of the turbine 230 and upstream of a portion of the engine 10. In one embodiment, as Figure 8 shown, the portion of the propulsion system 10 is the expansion section 30, or more particularly, the low-speed spool (e.g., low-pressure turbine or medium-pressure turbine) or the exhaust section 36 of the propulsion system 10.

[0058] In various embodiments, the thermal load 250 is positioned in thermal communication with the fluid circuit 210 downstream of the turbine 260. In certain embodiments, such as those described above, the thermal load 250 includes a lubricant system 252 positioned in thermal communication with the fluid circuit 210 downstream of the turbine 260. In various embodiments, the thermal load 250 includes a load heat exchanger 330, which is positioned in thermal communication with the fluid circuit 210 downstream of the turbine 260. In certain embodiments, the load heat exchanger 330 includes one or more of an electric motor, a computing system, or an environmental control system (ECS) (e.g., the computing system 140 and / or the ECS system 150 described with respect to Figure 1 ). The load heat exchanger 330 can be configured to provide fluid from the fluid circuit 210 as a cooling fluid in fluid thermal communication with an electric motor, a computing system, or an environmental control system or one or more of them. Various embodiments of the electric motor can include an electric motor and / or a generator, a hybrid electric device, etc. In various embodiments, the computing system can include avionics, an engine control device, a vehicle control system, or other electronic devices including one or more processors, storage devices, communication devices, circuits, or other electrical or electronic systems. In still various other embodiments, the ECS can include a fluid for one or more in the vehicle's cockpit, a heat transfer fluid for the vehicle, or other fluid devices.

[0059] Embodiments of the thermal load 250 can include a first thermal load positioned in thermal communication with the fluid circuit 210 downstream of the turbine 260, and a second thermal load positioned in thermal communication with the fluid circuit 210 downstream of the turbine 230 and upstream of the flow device 240. In certain embodiments, the first thermal load includes, for example, the load heat exchanger 330 described herein. In still certain other embodiments, the second thermal load includes a lubricant heat exchanger 320 and a lubricant system 252.

[0060] Various embodiments of the energy conversion system 200 can include one or more first valves 290 to divide the fluid at the fluid circuit 210 into a first flow 221 and a second flow 222. The system 200 can also include one or more second valves 291 to reconnect the flows 221, 222. The first valve 290 is positioned upstream of the lubricant heat exchanger 320 and the load heat exchanger 330. The second valve 291 is positioned downstream of the lubricant heat exchanger 320 and the load heat exchanger 330. In certain embodiments, the system 200 includes an exhaust slot 295 where fluid from the fluid circuit 210 can be disposed. The exhaust slot 295 can include one or more of an exhaust slot at the turbine 260, an exhaust slot at the propulsion system 10, or another exhaust slot or an exhaust slot in the surrounding environment.

[0061] Now refer to Figure 9 andFigures 10A-10B , The flowchart outlines the steps of a method (hereinafter referred to as "Method 1000") for operating a propulsion system and an energy conversion system. The steps of Method 1000 can be stored as instructions in the memory of a computing device or controller (such as one or more computing systems 140 of the propulsion system 10 or the vehicle 100). The computing system 140 can include one or more processors operatively coupled to the memory to execute the instructions for operation at various embodiments such as the propulsion systems or vehicles provided herein. Various embodiments of the methods provided herein can be computer-implemented methods executable by the computing device 140.

[0062] The operation includes determining, at 1010, a base schedule for operating a flow control device (e.g., the flow control device 220) to extract a compressed fluid flow from a compressor section of the propulsion system (e.g., the compressor section 20), and operating, at 1020, the flow control device to allow the compressed fluid flow to a turbine (e.g., the turbine 230) operatively coupled to a drive shaft (e.g., the drive shaft 231), where the drive shaft is operatively coupled to a load device (e.g., the load device 270). The method of operation can further include extracting the compressed fluid flow from the compressor section at 1012 and flowing the compressed fluid flow to the turbine based on the base schedule.

[0063] In certain embodiments, the base schedule of the flow control device, or in particular the operation of the flow control device (e.g., opening or closing, or a portion thereof), corresponds to the mechanical or corrected rotor speed at the HP spool or LP spool, or the rate of change thereof (e.g., transient change or an input signal corresponding to a desired transient change), or the compressor section inlet or outlet temperature (e.g., Station 2.0, Station 2.5, Station 3.0), the turbine section temperature (e.g., Station 4.0, Station 4.5, etc.), the exhaust gas temperature (EGT), the engine pressure ratio (EPR), the compressor pressure ratio, the predetermined heat transfer requirements of the thermal management system (e.g., based on or corresponding to the throttle setting, fan, propeller or LP spool torque requirements, heat exchanger discharge, motor load requirements, etc., or a combination thereof). In a particular embodiment, the operation of the flow control device is based on the heat capacity of any one or more heat exchangers at, for example, the heat load 250 (or other heat exchangers depicted or described herein). For example, when the propulsion system 10 operates under conditions where the air from the fan bypass flow path, the third flow path, or the core flow path is insufficient to meet the heat demand at the energy conversion system or one or more heat exchangers described herein, the control method can close the flow control device until the propulsion system operates under conditions that meet the heat demand of the system. Figures 1-8 The heat capacity of the heat exchanger). For example, when the propulsion system 10 operates under conditions where the air from the fan bypass flow path, the third flow path, or the core flow path is insufficient to meet the heat demand at the energy conversion system or one or more heat exchangers described herein, the control method can close the flow control device until the propulsion system operates under conditions that meet the heat demand of the system.

[0064] Various embodiments of the base schedule may correspond to the initial or baseline operation of the energy conversion system 200 and the propulsion system 10. In various embodiments, the method of operation includes receiving an input signal from a propulsion system sensor at a base propulsion system control. In certain embodiments, the input signal indicates, for example, the power or thrust output required from an avionics system, throttle, or other suitable input device. In certain embodiments, a supervisory computing system may provide the input signal to the base propulsion system control. The supervisory computing system may include a controller configured to receive signals and send signals to a plurality of propulsion systems, vehicle systems, avionics, or other computing devices. The supervisory computing system may adjust, correct, resolve, average, or determine the input signal or a modification to the input signal based on the operating mode of another propulsion system, the operating mode of the vehicle (e.g., altitude, attitude, angle of attack, airspeed, physical properties of the air, or other suitable operating variables). In various embodiments, the base propulsion system control receives an input signal, such as described herein, that corresponds to the desired operating mode of the propulsion system and the energy conversion system.

[0065] The method of operation further includes adjusting or modulating the energy conversion system at 1030 based on propulsion system operability, core engine operating parameter limits, or thermal management requirements, or a combination thereof. The core engine operating parameter limits correspond to pressure and / or temperature limits at the core engine during operation. In certain embodiments, the parameter limits correspond to gas flow path pressure and / or temperature limits at the core engine, entering the core engine, or exiting the core engine. In other embodiments, the parameter limits correspond to gas flow path pressure and / or temperature limits at the core engine relative to the corresponding speed of the HP spool or the desired HP spool speed.

[0066] In still other various embodiments, the thermal management requirements correspond to a desired heat transfer rate, maintaining a desired fluid temperature, or adjusting / modulating the fluid temperature. In certain embodiments, the thermal management requirements correspond to maintaining a desired lubricant temperature via heat transfer with a compressed air stream from the propulsion system. In a particular embodiment, the thermal management requirements correspond to reducing or maintaining the lubricant temperature, e.g., to maintain or improve lubricant quality, to produce desired physical properties at the lubricant system (e.g., to produce a desired viscosity, flow rate, pressure, temperature, etc. of the lubricant at a bearing assembly or gear assembly), or to produce a desired vibration response at a bearing assembly or rotor assembly (e.g., HP spool, LP spool, or fan section). In a particular embodiment, the thermal management requirements correspond to increasing or maintaining the lubricant temperature, e.g., to maintain the lubricant within a desired physical parameter range or temperature range with respect to reducing or eliminating undesired vibrations, rotor whirl, or to produce a desired vibration response at the rotor assembly.

[0067] Various other embodiments include adjusting or modulating the energy conversion system based on the operability of the propulsion system, such as by adjusting the opening or closing amplitude of a flow control device (e.g., flow control device 220) based on keeping the HP spool and / or LP spool within operability limits. The operability limits may correspond to the surge line or stall line of the compressor section.

[0068] The method may further include determining, at 1040, the more stringent limit of the propulsion system operability, core engine operating parameter limits, or thermal management requirements, and selecting, at 1050, the more stringent limit to adjust or modulate the energy conversion system. In a particular embodiment, adjusting or modulating the energy conversion system includes adjusting or modulating the flow control device, such as to adjust the flow rate or pressure of the fluid flow received from the compressor section.

[0069] Embodiments of the method further include adjusting or modulating the energy conversion system at 1060 according to or corresponding to the more stringent limit of the propulsion system operability, core engine operating parameter limits, or thermal management requirements. Accordingly adjusting or modulating the energy conversion system may further include opening the flow control device to the maximum allowable open position based on the determined more stringent limit. Accordingly adjusting or modulating the energy conversion system may further include extracting the maximum flow rate or maximum pressure of the fluid flow from the compressor section based on the determined more stringent limit.

[0070] Further embodiments of the method may further include adjusting or modulating the energy conversion system at 1070 according to or corresponding to a predetermined upper limit or a predetermined lower limit corresponding to the core engine. In certain embodiments, the predetermined limit corresponds to the maximum or minimum compressor outlet pressure (or inlet pressure of the combustion section, or Station 3.0), the maximum or minimum compressor outlet temperature (or inlet temperature of the combustion section, or Station 3.0), or the health and safety limits at the core engine.

[0071] In a particular embodiment, the method includes a serial process for determining the adjustment or modulation of the energy conversion system or particularly the flow control device: 1) determining a base schedule; 2) determining the more stringent operability adjustment limit, core engine parameter limit, or thermal management requirement; 3) selecting the maximum opening or corresponding flow rate or pressure based on the determined more stringent limit; 4) adjusting or modulating based on the predetermined upper limit or lower limit, or a combination of the steps.

[0072] In various embodiments, methods for energy conversion include: extracting a compressed fluid stream from a compressor section at 1012 and directing the compressed fluid stream to a turbine based on a base schedule; directing the compressed fluid to the turbine at 1014 based on the base schedule; expanding the compressed fluid stream passing through the turbine at 1016 to generate an output torque at a drive shaft to operate a load device; and flowing the expanded compressed fluid stream from the turbine at 1018 to be in thermal communication with a heat load, such as described herein with respect to Figures 1-8 as described.

[0073] In certain embodiments, the method includes flowing the compressed fluid from the heat load to a fan bypass flow of the propulsion system at 1022. In an embodiment, the method includes flowing the compressed fluid from the heat load to a third flow path of the propulsion system at 1024. In another embodiment, the method includes flowing a compressed fluid stream from a compressor section of the propulsion system to be in thermal communication with a first heat exchanger located at a third flow path of the propulsion system at 1026.

[0074] The computing system 140 and method can further include feeding an actual position of a flow control device (e.g., valve open / closed percentage, valve flow area, actuator open / closed percentage, linear variable differential transformer signal, rotary variable differential transformer signal, or other signal indicative of the flow rate of fluid across the flow control device) into a control loop of a base power plant controller, such as the computing device 140. It should be understood that the methods provided herein can include receiving or sending signals indicative of flow rate, pressure, temperature, physical properties of the fluid, valve or actuator position, rotational speed, or other signals indicative of propulsion system operation and energy conversion system operation.

[0075] It should be understood that the computing system 140 can include components suitable for processor-based functions and operations at the propulsion system 10, vehicle 100, and energy conversion system 200. The computing system 140 can correspond to any suitable processor-based device, including one or more computing devices, such as those described above. In certain embodiments, the computing system 140 is a full authority digital engine controller (FADEC) for a gas turbine engine, or other computing module or controller configured to execute instructions for operating the propulsion system or vehicle. The computing system 140 can include a processor 142 and an associated memory 144 configured to execute various computer-implemented functions.

[0076] As shown, computing system 140 may include control logic 146 stored in memory 144. Control logic 146 may include instructions 147 that, when executed by one or more processors 142, cause the one or more processors 142 to perform operations, such as one or more steps of method 1000 provided herein. Additionally, computing system 140 may further include a communication interface module 148. In some embodiments, communication interface module 148 may include associated electronic circuitry for sending and receiving data. Thus, communication interface module 148 of computing system 140 may be used to send data to and / or receive data from propulsion system 10. Additionally, communication interface module 148 may also be used to communicate with any other suitable components of propulsion system 10, as described herein.

[0077] It should be understood that communication interface module 148 may be any combination of suitable wired and / or wireless communication interfaces and, thus, may be communicatively coupled to one or more components of the power generation system via a wired and / or wireless connection or distributed network. As described herein, communication interface module 148 may include any suitable wired and / or wireless communication link for transmitting communications and / or data. For example, module 148 may include a SATCOM network, an ACARS network, an ARINC network, a SITA network, an AVICOM network, a VHF network, an HF network, a Wi-Fi network, a WiMAX network, a gatelink network, etc.

[0078] Embodiments of propulsion system 10, vehicle 100, and energy conversion system 200 may, for example, improve system efficiency by utilizing the pressure of the fluid from the compressor section of the propulsion system or particularly from the high-pressure compressor rather than utilizing a pressure regulator or releasing the fluid to, for example, atmospheric conditions. Embodiments provided herein may further improve the heat transfer of the lubricant from the lubricant system. Still further, embodiments provided herein may improve the heat transfer from the lubricant and additionally from one or more load devices (such as a load heat exchanger). Additionally or alternatively, the cooling fluid at fluid circuit 210 may be adjusted, for example, via flow control device 220 and / or flow device 240 independently of the operating conditions at propulsion system 10.

[0079] One or more components of the propulsion system 10 and the energy conversion system 100 described herein may be manufactured or formed using any suitable process (e.g., an additive manufacturing process, such as a 3-D printing process). The use of such processes may allow such components to be integrally formed as a single monolithic component, or formed as any suitable number of sub-components, or formed at scales and complexities not previously permitted or contemplated in the art. In particular, additive manufacturing processes may allow such components to be integrally formed and include a variety of features that are not possible to achieve when using existing manufacturing methods. For example, the additive manufacturing methods described herein may allow the turbine 230 and the flow control device 220 to be manufactured as a single monolithic component. In a further embodiment, the additive manufacturing methods described herein allow for the manufacture of the turbine 230, the flow control device 220, and at least a portion of the conduit 210 having unique features, configurations, thicknesses, materials, densities, fluid channels, manifolds, and mounting structures that may not be achievable or practical using existing manufacturing methods.

[0080] Suitable additive manufacturing techniques according to the present disclosure include, for example, fused deposition modeling (FDM), selective laser sintering (SLS), 3D printing (e.g., by inkjet, laser jet, and binder jet), stereolithography (SLA), direct selective laser sintering (DSLS), electron beam sintering (EBS), electron beam melting (EBM), laser engineered net shaping (LENS), laser net shaping manufacturing (LNSM), direct metal deposition (DMD), digital light processing (DLP), direct selective laser melting (DSLM), selective laser melting (SLM), direct metal laser melting (DMLM), and other known processes. Suitable powder materials for manufacturing the single structures provided herein as a whole or structures at the scales and complexities provided herein include metal alloys, polymer, or ceramic powders. Exemplary metal powder materials are stainless steel alloys, cobalt-chromium alloys, aluminum alloys, titanium alloys, nickel-based superalloys, and cobalt-based superalloys. Additionally, suitable alloys may include those that have been designed to have good oxidation resistance, known as "superalloys," which have acceptable strength under the high-temperature operation of a gas turbine engine, e.g., Hastelloy, Inconel alloys (e.g., IN 738, IN 792, IN 939), Rene alloys (e.g., Rene N4, Rene N5, Rene 80, Rene 142, Rene 195), Haynes alloys, Mar M, CM 247, CM 247LC, C263, 718, X-850, ECY 768, 282, X45, PWA 1483, and CMSX (e.g., CMSX-4) single crystal alloys. The manufactured objects of the present disclosure may be formed with one or more selected crystalline microstructures, such as directionally solidified ("DS") or single crystal ("SX").

[0081] The written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system and performing any combined method. The scope of the patent for the invention is defined by the claims and may include other examples that occur to a person skilled in the art. If these other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims, then these other examples are intended to fall within the scope of the claims.

[0082] A further aspect of the invention is provided by the subject matter of the following clauses:

[0083] 1. A method for energy conversion of a vehicle, the method comprising: extracting a compressed fluid flow from a compressor section of a propulsion system; directing the compressed fluid flow to a turbine operably coupled to a drive shaft, wherein the drive shaft is operably coupled to a load device; expanding the compressed fluid flow passing through the turbine to generate an output torque at the drive shaft to operate the load device; and directing the expanded compressed fluid flow from the turbine to be in thermal communication with a heat load.

[0084] 2. The method according to any one or more of the clauses herein, the method comprising: directing the compressed fluid from the heat load to a fan bypass flow of the propulsion system.

[0085] 3. The method according to any one or more of the clauses herein, the method comprising: directing the compressed fluid from the heat load to a third flow path of the propulsion system.

[0086] 4. The method according to any one or more of the clauses herein, the method comprising: directing the compressed fluid flow from the compressor section of the propulsion system to be in thermal communication with a first heat exchanger located at a third flow path of the propulsion system.

[0087] 5. The method according to any one or more of the clauses herein, wherein the heat load is an air-fluid heat exchanger, and wherein directing the expanded compressed fluid flow from the turbine to be in thermal communication with the heat load includes providing the compressed fluid flow to be in thermal communication with a fuel flow.

[0088] 6. The method according to any one or more of the clauses herein, the method comprising: providing the fuel flow to be in thermal communication with a fuel-fluid heat exchanger after being in thermal communication with the compressed fluid flow.

[0089] 7. The method according to any one or more of the items herein, the method comprising: providing the fuel stream to a heat addition system of the propulsion system after thermal communication with the fuel-fluid heat exchanger.

[0090] 8. The method according to any one or more of the items herein, the method comprising: deoxygenating the fuel stream after thermal communication with the fuel-cooler fluid cooler.

[0091] 9. The method according to any one or more of the items herein, the method comprising: providing the fuel stream to be in thermal communication with a heater after thermal communication with the fuel-fluid heat exchanger.

[0092] 10. The method according to any one or more of the items herein, wherein providing the fuel stream to be in thermal communication with the heater comprises providing the fuel stream to be in thermal communication with a waste heat recovery system.

[0093] 11. The method according to any one or more of the items herein, wherein providing the fuel stream to be in thermal communication with the waste heat recovery system comprises: flowing a heat transfer fluid in a closed loop in thermal communication with an expansion section or an exhaust section of the propulsion system, wherein flowing the heat transfer fluid in thermal communication with the expansion section or the exhaust section receives thermal energy generated by exhaust at the propulsion system; and providing thermal energy from the heat transfer fluid to the fuel stream via the heater.

[0094] 12. The method according to any one or more of the items herein, the method comprising: flowing the fuel stream in thermal communication with a waste heat recovery heat exchanger that is in parallel with the fuel-fluid heat exchanger.

[0095] 13. The method according to any one or more of the items herein, wherein providing thermal energy from the heat transfer fluid to the fuel stream via the heater is downstream of the fuel-fluid heat exchanger with respect to the fuel stream.

[0096] 14. The method according to any one or more of the items herein, wherein the heat load is configured to transfer thermal energy from a lubricant, a gear assembly cooling fluid, a propeller control mechanism cooling fluid, or an electric motor cooling fluid.

[0097] 15. The method according to any one or more of the items herein, wherein the heat load is configured as an air-cooled oil cooler.

[0098] 16. A vehicle, the vehicle comprising: a propulsion system including a fan section, a compressor section, a heat addition system, and an expansion section arranged in serial flow, wherein a core flow path is formed through the compressor section, the heat addition system, and the expansion section, and wherein a fan bypass flow is configured to bypass the core flow path, and wherein a third flow path is configured to bypass the heat addition system; an energy conversion system including a fluid circuit forming a serial fluid communication of an oxidizer flow from the compressor section to a turbine, and wherein the fluid circuit provides a serial fluid communication from the turbine to a heat load, and wherein the oxidizer flow at the heat load is in thermal communication with a fluid flow at the heat load; and a load device operably coupled to the turbine by a drive shaft, wherein the turbine and the drive shaft are configured to generate an output torque at the load device via expansion of the oxidizer flow at the turbine.

[0099] 17. The vehicle according to any one or more of the items herein, the vehicle comprising: a first heat exchanger positioned in thermal communication with the third flow path, wherein the first heat exchanger is positioned in thermal communication with the fluid circuit and arranged in serial flow between the compressor section and the turbine.

[0100] 18. The vehicle according to any one or more of the items herein, the vehicle comprising: a fuel system configured to provide a fuel flow in thermal communication with the oxidizer flow at the heat load.

[0101] 19. The vehicle according to any one or more of the items herein, wherein the fuel system includes: a fuel-fluid heat exchanger configured to receive the fuel flow in thermal communication with the oxidizer flow from the turbine, and wherein the fuel flow is caused to flow in thermal communication with a flow of one or more of a lubricant, a gear assembly cooling fluid, a propeller control mechanism cooling fluid, or a motor cooling fluid.

[0102] 20. The vehicle according to any one or more of the items herein, the vehicle comprising: a waste heat recovery system configured to be in thermal communication with the fuel flow.

[0103] 21. A vehicle configured to perform the method according to any one or more of the items herein.

[0104] 22. A computer-implemented method for operating a vehicle, the method comprising: determining a baseline schedule for operating a flow control device to extract a compressed fluid flow from a compressor section of the propulsion system; operating the flow control device to allow the compressed fluid flow to a turbine operably coupled to a drive shaft, the drive shaft being operably coupled to a load device; adjusting the energy conversion system based on propulsion system operability, core engine operating parameter limits, or thermal management requirements; determining a more stringent limit of the propulsion system operability, core engine operating parameter limits, or thermal management requirements; and adjusting the energy conversion system corresponding to the more stringent limit of the propulsion system operability, the core engine operating parameter limits, or the thermal management requirements.

[0105] 22. The computer-implemented method according to any one or more of the items herein, the method comprising selecting a more stringent limit to adjust or modulate the energy conversion system.

[0106] 23. The computer-implemented method according to any one or more of the items herein, the method comprising modulating the energy conversion system corresponding to a predetermined upper limit or a predetermined lower limit corresponding to the core engine.

[0107] 24. The computer-implemented method according to any one or more of the items herein, the computer-implemented method comprising the method according to any one or more of the items herein.

[0108] 25. A computing system for a vehicle, the computer system comprising one or more processors and one or more memories, wherein the memory is configured to store instructions that, when executed by the one or more processors, perform operations comprising the method according to any one or more of the items herein.

[0109] 26. A computing system for a vehicle, the computer system comprising one or more processors and one or more memories, wherein the memory is configured to store instructions that, when executed by the one or more processors, perform operations comprising the computer-implemented method according to any one or more of the items herein.

[0110] 27. The computing system according to any one or more of the items herein, the computing system being configured to operate the vehicle according to any one or more of the items herein.

[0111] 28. The vehicle according to any one or more of the items herein, the vehicle comprising the computing system according to any one or more of the items herein.

[0112] 29. A propulsion system, the propulsion system including the computing system described in any one or more of the items herein.

[0113] 30. A propulsion system, the propulsion system being configured to perform the steps of the method described in any one or more of the items herein.

[0114] 31. A vehicle according to any one or more of the items herein, the flow control device being a variable area nozzle formed at the turbine.

Claims

1. A method for energy conversion of a vehicle, characterized in that, The method includes: extracting a compressed fluid flow from a compressor section of a propulsion system, wherein the propulsion system includes a fan section, a compressor section, a heat addition system, and an expansion section in a serial flow arrangement; passing the compressed fluid flow from the compressor section through a fan bypass flow and then into a flow control device; directing, via the flow control device, a first portion of the compressed fluid flow from the compressor section to a turbine, wherein the turbine is operably coupled to a drive shaft, and wherein the drive shaft is operably coupled to a load device; directing, via the flow control device, a second portion of the compressed fluid flow from the compressor section to a flow device; expanding the first portion of the compressed fluid flow passing through the turbine to generate an output torque at the drive shaft to operate the load device; passing the expanded compressed fluid flow from the turbine to provide heating or cooling for a heat load; and mixing, via the flow device, the second portion of the compressed fluid flow from the compressor section with the expanded compressed fluid flow from the heat load to provide a mixed flow of compressed fluid.

2. The method according to claim 1, wherein The method includes: passing the compressed fluid from the heat load to the fan bypass flow of the propulsion system.

3. The method according to claim 1, wherein The method includes: passing the compressed fluid from the heat load to a third flow path of the propulsion system.

4. The method according to claim 1, wherein The method includes: passing the compressed fluid flow from the compressor section of the propulsion system to be in thermal communication with a first heat exchanger located at a third flow path of the propulsion system.

5. The method according to claim 1, wherein wherein the heat load is an air-fluid heat exchanger, and wherein passing the expanded compressed fluid flow from the turbine to be in thermal communication with the heat load includes providing the compressed fluid flow to be in thermal communication with a fuel flow.

6. The method according to claim 5, wherein The method includes: after being in thermal communication with the compressed fluid flow, providing the fuel flow to be in thermal communication with a fuel-fluid heat exchanger.

7. The method according to claim 6, wherein The method includes: after being in thermal communication with the fuel-fluid heat exchanger, providing the fuel flow to the heat addition system of the propulsion system.

8. The method according to claim 7, characterized in that, The method includes: after being in thermal communication with the fuel-cooler fluid cooler, deoxygenating the fuel flow.

9. The method according to claim 7, wherein The method includes: after being in thermal communication with the fuel-fluid heat exchanger, providing the fuel flow to be in thermal communication with a heater.

10. The method according to claim 9, characterized in that, wherein providing the fuel flow to be in thermal communication with the heater includes providing the fuel flow to be in thermal communication with a waste heat recovery system.

11. The method according to claim 10, wherein wherein providing the fuel flow to be in thermal communication with the waste heat recovery system includes: flowing a heat transfer fluid in a closed loop in thermal communication with an expansion section or an exhaust section of the propulsion system, wherein flowing the heat transfer fluid in thermal communication with the expansion section or the exhaust section receives thermal energy generated by the exhaust at the propulsion system; and providing thermal energy from the heat transfer fluid to the fuel flow via the heater.

12. The method according to claim 11, wherein The method includes: flowing the fuel flow in thermal communication with a waste heat recovery heat exchanger, the waste heat recovery heat exchanger being in parallel with the fuel-fluid heat exchanger.

13. The method according to claim 12, wherein Wherein the provision of heat energy from the heat transfer fluid to the fuel stream via the heater is downstream of the fuel-fluid heat exchanger with respect to the fuel stream.

14. The method according to claim 1, characterized in that, Wherein the heat load is configured as an air-cooled oil cooler.

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