Cryogenic fuel distribution systems including heat exchangers and related methods

Abstract

Heat exchangers for cryogenic fuel distribution systems and related methods are disclosed herein. An example aircraft disclosed herein includes a cryogenic fuel system including a cryogenic fuel, a hydraulic system including a hydraulic fluid, a gas turbine engine fluidly coupled to the cryogenic fuel system, and a heat exchanger fluidly coupled to the cryogenic fuel system, the heat exchanger is used to exchange heat between the cryogenic fuel and at least one of (1) hydraulic fluid or (2) working fluid thermally coupled to the hydraulic system.

Description

Technical Field

[0001] This disclosure generally relates to hydrogen fuel distribution systems, and more specifically, to cryogenic fuel distribution systems and related methods including heat exchangers. Background Technology

[0002] An aircraft fuel distribution system supports fuel storage and fuel distribution to the engines. In some examples, the fuel system may include a single gravity-fed fuel tank with associated fuel lines connecting it to the aircraft engines. In some examples, multiple fuel tanks may exist as part of the fuel distribution system. These tanks may be located in the wings, fuselage, and / or tail of the aircraft. The tanks may be connected to internal fuel pumps using associated valves and / or piping to allow for engine fuel supply, refueling, unloading, individual tank isolation, and / or overall optimization of the aircraft's center of gravity. Attached Figure Description

[0003] The specification with reference to the accompanying drawings sets forth a complete and enabling disclosure of preferred embodiments for those skilled in the art, including its best mode, wherein:

[0004] Figure 1 This is a simplified illustration of an aircraft including a hydrogen fuel distribution system, which includes fuel distribution controller circuitry, and in which the teachings of this disclosure can be implemented.

[0005] Figure 2A It is feasible. Figure 1 A schematic diagram of the first fuel distribution system, illustrating an example of fuel distribution.

[0006] Figure 2B It is feasible. Figure 1 A schematic diagram of a second fuel distribution system, illustrating an example of fuel distribution.

[0007] Figure 3 It is feasible. Figure 1 A schematic diagram of a third fuel distribution system, illustrating an example of fuel distribution.

[0008] Figure 4 It is feasible. Figure 1 Example of fuel distribution: Schematic diagram of the fourth fuel distribution system.

[0009] Figure 5 yes Figure 1 Block diagram of the fuel distribution controller circuit.

[0010] Figure 6 This indicates that it can be executed, instantiated, and / or implemented by the example programmable circuit. Figure 5 A flowchart of example machine-readable instructions and / or example operations for the fuel distribution controller circuit.

[0011] Figure 7 This is a block diagram of an example processing platform, which includes programmable circuitry configured to execute, instantiate, and / or perform example machine-readable instructions and / or perform... Figure 6 Example operations to implement Figure 5 The fuel distribution controller circuit. Detailed Implementation

[0012] During operation, the hydraulic systems of gas turbine engines and aircraft become hot due to friction and hydraulic system inefficiency. Furthermore, cryogenic fuel can be heated before being injected into the combustor to prevent large thermal gradients within the combustor and to enable accurate measurement of the fuel entering the combustor. The example fuel distribution systems disclosed herein include heat exchangers that exchange heat between the hydraulic fluid of the gas turbine engine and / or aircraft and cryogenic fuel (e.g., liquid hydrogen). Some example fuel distribution systems disclosed herein include a heat transfer bus that includes an intermediate working fluid for transferring heat between the hydraulic fluid and the cryogenic fuel. The examples disclosed herein reduce the total number and / or size of heat exchangers required to operate aircraft fueled by cryogenic fuels.

[0013] The terms “upstream” and “downstream” refer to the relative directions of fluid flow within a fluid path. For example, “upstream” refers to the direction from which fluid flows, and “downstream” refers to the direction towards which fluid flows. Various terms are used herein to describe the orientation of a feature. As used herein, the orientation of a feature, force, and moment is described with reference to the yaw axis, pitch axis, and roll axis of the vehicle associated with the feature, force, and moment. Typically, figures are annotated with a set of axes including the yaw axis Y, the roll axis R, and the pitch axis P. In some examples disclosed herein, a reference clock position describes the orientation of a feature. In these examples, the clock position is described by referring to the position of the feature in a plane (yaw-pitch plane) defined by the yaw axis and the pitch axis, where the 12 o'clock position is oriented along the yaw axis.

[0014] Aircraft and gas turbine engines may include hydraulic systems to control aerodynamic surfaces, control valves, landing gear, and / or other systems. During operation, inefficiencies and friction increase the temperature of the hydraulic fluid. In some examples, if the hydraulic fluid overheats, it reduces or diminishes the efficiency of the hydraulic system. To dissipate excess heat in the hydraulic fluid, some existing aircraft include dedicated heat exchangers that cool the fluid via radiators (e.g., the aircraft's surrounding environment). In recent years, hydrogen has been explored as a fuel source for aircraft. One method for storing the large quantities of hydrogen needed to fuel gas turbine engines is cryogenic storage. In some systems, hydrogen is heated to a non-cryotemperature temperature before being injected into the combustor to prevent damage to the gas turbine engine's combustor and to allow monitoring of the hydrogen entering the combustor. This heating of cryogenic hydrogen may require dedicated heat exchangers and heat sources, such as bleed air from the gas turbine engine. In some such examples, the siphoning of bleed air from the gas turbine engine reduces the efficiency of the gas turbine engine.

[0015] Examples disclosed herein include cryogenic fuel distribution systems comprising heat exchangers that exchange heat between hydraulic fluid and cryogenic fuel. Some examples disclosed herein include fuel distribution systems comprising a first heat exchanger that transfers heat between hydraulic fluid and cryogenic fuel, and a second heat exchanger that exchanges heat between the cryogenic fuel and a secondary heat source. In some such examples disclosed herein, the first heat exchanger is located upstream of the second heat exchanger in the fuel distribution system. Some examples disclosed herein include heat transfer buses comprising a working fluid flowing through a series of heat exchangers to transfer heat between a cryogenic fuel source, hydraulic fluid, and a secondary heat source. Examples disclosed herein reduce the design requirements of dedicated hydrogen-heated heat exchangers, which reduces the weight of such heat exchangers and the associated requirements for heat sources (e.g., bleed air). Examples disclosed herein alleviate the need for dedicated hydraulic fluid-cooled heat exchangers. Due to the reduced requirement for bleed air, examples disclosed herein reduce the weight of the aircraft and improve the efficiency of gas turbine engines.

[0016] Figure 1 This is an example illustration of an aircraft 100 including an example fuel distribution system 102. Figure 1 In the example shown, the fuel distribution system 102 includes a cryogenic fuel tank 104 that supplies cryogenic fuel to the gas turbine engine 106. Figure 1 In the example shown, the aircraft 100 includes a fuel distribution management circuit 108. Figure 1 In the example shown, aircraft 100 includes an aircraft hydraulic system 110 and an aerodynamic surface 112. Figure 1 In the example shown, the gas turbine engine 106 includes an engine hydraulic system 114.

[0017] exist Figure 1 In the example shown, aircraft 100 is a fixed-wing commercial aircraft. In other examples, aircraft 100 could be another type of fixed-wing aircraft (e.g., unmanned aerial vehicle (UAV), military aircraft, etc.), rotorcraft (e.g., helicopter, etc.), or spacecraft (e.g., launch vehicle, satellite, manned spacecraft, etc.). Figure 1 In the examples shown, aircraft 100 includes a single gas turbine engine (e.g., gas turbine engine 106, etc.) that propels and / or powers aircraft 100. Gas turbine engine 106 can be implemented by any suitable type of gas turbine engine 106, including turbofan engines, turbojet engines, turboprop engines, turboshaft engines, and / or another type of turbomachinery. In some examples, aircraft 100 may include multiple gas turbine engines, such as multiple gas turbine engines mounted under the wings of aircraft 100. While the examples described herein are based on aircraft 100 and gas turbine engine 106, it should be understood that the examples described herein are applicable to any system that burns cryogenic fuels and / or otherwise includes cryogenic cooling fuels and hydraulic systems.

[0018] Fuel distribution system 102 is a cryogenic fuel system that delivers fuel (e.g., hydrogen, methane, etc.) from cryogenic fuel tank 104 to gas turbine engine 106. In some examples, fuel distribution system 102 includes one or more pumps that drive fuel from cryogenic fuel tank 104 to gas turbine engine 106. In some examples, fuel distribution system 102 includes one or more heat exchangers that heat the fuel prior to combustion within gas turbine engine 106. For example, fuel distribution system 102 may include one or more heat exchangers that transfer heat between the fuel in fuel distribution system 102 (e.g., fuel that heats fuel distribution system 102, etc.) and the hydraulic fluid of aircraft hydraulic system 110 and / or engine hydraulic system 114 (e.g., hydraulic fluid that cools hydraulic systems 110, 114, etc.). In some examples, the fuel distribution system 102 includes an additional heat exchanger that transfers heat between the fuel in the fuel distribution system 102 and another heat source associated with the aircraft 100 (e.g., the flow through the gas turbine engine 106, the surrounding environment of the aircraft 100, the lubrication of the gas turbine engine, electric heaters, etc.). The following is in conjunction with... Figure 2A-4 An example implementation of the fuel distribution system 102 is described.

[0019] Cryogenic fuel tank 104 is a pressure vessel containing cryogenic fuel for combustion within a gas turbine engine 106. For example, cryogenic fuel tank 104 may include liquefied hydrogen. In some such examples, cryogenic fuel tank 104 may contain hydrogen in various states, including liquid, gaseous, supercritical, cryogenic, and / or cryogenically compressed states. Cryogenic fuel tank 104 may be stored in any suitable location on the aircraft (e.g., in the wing, in the fuselage, in an external tank, etc.). In some examples, cryogenic fuel tank 104 may include multiple tanks (referred to herein as a tank group, etc.). In some such examples, aircraft 100 may include one or more tanks containing liquid hydrogen and one or more tanks containing gaseous hydrogen. In some examples, cryogenic fuel tank 104 may contain liquefied and / or cryogenically compressed hydrocarbons, such as cryogenic methane (e.g., liquefied methane, etc.). In some examples, cryogenic fuel tank 104 may be implemented by multiple tanks containing fuel. For example, cryogenic fuel tank 104 may include one or more tanks containing cryogenic hydrogen and one or more tanks containing cryogenic methane. Additionally or alternatively, the aircraft 100 may include one or more additional fuel tanks containing jet propellant 1 (JP1) and / or other non-cryogenic hydrocarbons.

[0020] Hydraulic systems 110 and 114 include hydraulic fluid that can be used, respectively, to control (e.g., move, actuate, control, etc.) the position of features of aircraft 100 and gas turbine engine 106. For example, aircraft hydraulic system 110 can control the position of aerodynamic surface 112 and / or other features of the control system of aircraft 100. Movement of aerodynamic surface 112 can be used to modify the orientation of aircraft 100 during operation (e.g., maneuver aircraft 100, etc.). Figure 1 In the example shown, aerodynamic surface 112 is an aileron. Additionally or alternatively, aerodynamic surface 112 may include one or more flaps, one or more elevators, one or more rudders, one or more spoilers, one or more slats, etc. In some examples, the aircraft hydraulic system 110 may similarly regulate the position of the aircraft 100's brakes, the extension and / or retraction of the aircraft 100's landing gear, the aircraft 100's thrust reversers, and / or the aircraft 100's doors.

[0021] Engine hydraulic system 114 adjusts the position of one or more control elements of gas turbine engine 106. For example, engine hydraulic system 114 can adjust the position of one or more fuel control valves, one or more lubricant valves, one or more variable stator blades, fan blade feathering, one or more exhaust control valves, etc. In some examples, one or both of hydraulic systems 110 and 114 can adjust the following combined... Figure 2A-4The fuel distribution system describes the position of the valves in the fuel distribution system.

[0022] During operation, friction and / or heat transfer from adjacent components of the aircraft 100 and / or gas turbine engine 106 increase the temperature of the hydraulic fluids in hydraulic systems 110, 114. In some examples, if the hydraulic fluids in hydraulic systems 110, 114 become overheated, the hydraulic fluids may denature and / or otherwise degrade, reducing the efficiency of hydraulic systems 110, 114. Example fuel distribution system 102 includes one or more heat exchangers that remove heat from the hydraulic fluids of the aircraft hydraulic system 110 and / or engine hydraulic system 114. In some such examples, the heat removed from the hydraulic fluids of hydraulic systems 110, 114 is transferred to the cryogenic fuel flowing from cryogenic fuel tank 104 to gas turbine engine 106. The following is combined with... Figure 2A-4 An example heat exchanger is described for transferring heat between the fuel and hydraulic fluid of one or both of the hydraulic systems 110, 114 in the fuel distribution system 102.

[0023] exist Figure 1 In this system, the fuel distribution system 102 is controlled and monitored by the fuel distribution management circuit 108. For example, the fuel distribution management circuit 108 can adjust the heat exchange in the fuel distribution system 102 (e.g., the heat exchange rate between the hydraulic fluid of hydraulic systems 110, 114 and the fuel, the heat exchange rate between the fuel and a secondary heat source, etc.) so that the fuel enters the gas turbine engine 106 in a gaseous and / or supercritical state / phase (e.g., the fuel phase changes from liquid to gas, the fuel phase changes from liquid to supercritical, etc.). In some examples, the fuel distribution system 102 may interface with one or more valves to change the flow rate of fuel through the heat exchanger of the fuel distribution system 102. The following is in conjunction with... Figure 5 An example implementation of the fuel distribution system 102 is described.

[0024] The embodiments described herein are also applicable to other applications using hydrogen (H2) as fuel in aircraft 100. The embodiments described herein are also applicable to engines other than gas turbine engines. For example, hydrogen can also be used as fuel for other generators. For example, the embodiments described herein are also applicable to fuel cells (e.g., hydrogen fuel cells, etc.) where hydrogen is provided to generate electricity through a reaction with air. Furthermore, the embodiments described herein are also applicable to fuel sources other than hydrogen. For example, the embodiments described herein are also applicable to liquefied and / or cryogenic hydrocarbons, such as methane (CH4).

[0025] Figure 2A It can be used for implementation Figure 1 Example of a fuel distribution system 102, block diagram of a first fuel distribution system 200. Figure 2AIn the example shown, the first fuel distribution system 200 includes Figure 1 The cryogenic fuel tank 104, low-pressure (LP) pump 204, first motor 206, first high-pressure (HP) pump 208, second motor 210, first heat exchanger 212, second heat exchanger 214, heat exchanger bypass 216, and heat exchanger bypass valve 217 are included. Figure 2A In the example shown, the second heat exchanger 214 receives heat from the secondary heat source 218. Figure 2A In the example shown, the fuel distribution system 102 includes a fuel metering valve 220 (FMV), a nozzle 222, and Figure 1 The combustion section 224 of the gas turbine engine 106. In some examples, the first fuel distribution system 200 may include additional components such as a throttle valve, an additional pump, an additional motor, and / or a shut-off overspeed valve (SOOV).

[0026] The first fuel distribution system 200 facilitates the flow from the cryogenic fuel tank 104 to the combustion zone 224 by connecting it in series through a series of components. Figure 2A In the example shown, the cryogenic fuel tank 104 is connected to the LP pump 204, which is powered by the first motor 206. Figure 2A In the example shown, after leaving LP pump 204, fuel flows into HP pump 208, which is powered by a second motor 210. Figure 2A In the example shown, after leaving HP pump 208, fuel flows into first heat exchanger 212. Figure 2A In the example shown, after leaving the first heat exchanger 212, fuel flows into the second heat exchanger 214 and / or the heat exchanger bypass 216. Figure 2A In the example shown, fuel enters FMV 220 after exiting the second heat exchanger 214 and / or heat exchanger bypass 216. Figure 2A In the example shown, after leaving FMV 220, fuel enters nozzle 222 and then enters combustion section 224.

[0027] Pumps 204 and 208 drive fuel through the first fuel distribution system 200. Figure 2AIn the example shown, the LP pump 204, driven by the first motor 206, supplies pressurized fuel to the HP pump 208. The HP pump 208, driven by the second motor 210, increases the fuel pressure before it enters the first heat exchanger 212. In some examples, pumps 204 and 208 are centrifugal pumps. In other examples, one or both of pumps 204 and 208 are other types of pumps (e.g., axial flow pumps, impeller pumps, gear pumps, etc.). In some examples, motors 206 and 210 are powered via the operation of the gas turbine engine 106. In other examples, motors 206 and 210 may be independently supplied with fuel (e.g., via a fuel cell, etc.) and / or powered (e.g., via an auxiliary gearbox of the gas turbine engine 106, via an electric motor, etc.). FMV 220 is a control valve that regulates the volume and / or mass of fuel entering the nozzle 222 and the combustion section 224. In some examples, the position of FMV 220 can be determined via... Figure 1 The fuel distribution management circuit 108 regulates and transmits fuel via... Figure 1 The engine hydraulic system 114 is controlled in the FMV. In some examples, the FMV 220 can be controlled based on the power requirements of the gas turbine engine 106 (e.g., based on operator input of the gas turbine engine 106, based on the flight phase of the gas turbine engine 106, etc.).

[0028] Nozzle 222 is a mechanical structure that directs the fuel flow into the combustion section 224. It should be understood that the gas turbine engine 106 may include multiple nozzles similar to nozzle 222. The combustion section 224 includes a combustor 225 that burns fuel, generating thrust to propel the engine. Figure 1 The aircraft 100. Combustion section 224 and / or burner 225 can be implemented by any suitable heat addition system for a turbine. For example, combustion section 224 can be implemented by one or more of a detonation combustion assembly, a rotating detonation combustion assembly, a pulse detonation combustion assembly, or other suitable heat addition assembly. In some example embodiments, the combustion section may include an annular burner, a canister burner, a tubular burner, a vortex burner (TVC), or other suitable combustion systems, or combinations thereof.

[0029] exist Figure 2A In the example shown, the first heat exchanger 212 includes a first inlet 226, a second inlet 228, a first outlet 230, and a second outlet 232. Figure 2A In the example shown, the first inlet 226 is connected to the outlet of the HP pump 208. Figure 2A In the example shown, the first outlet 230 is connected to the second heat exchanger 214 and the heat exchanger bypass valve 217. Figure 2AIn the example shown, the second inlet 228 and the second outlet 232 are connected to the hydraulic system 234. During operation, fuel from the HP pump 208 enters the first heat exchanger 212 via the first inlet 226, and hydraulic fluid from the hydraulic system 234 enters the first heat exchanger 212 via the second inlet 228. Heat is exchanged between the hydraulic fluid and the fuel within the first heat exchanger 212, which cools the hydraulic fluid and heats the fuel. After the heat exchange, the fuel exits the first heat exchanger 212 via the first outlet 230, and the hydraulic fluid exits the first heat exchanger 212 via the second outlet 232. The first heat exchanger 212 may be implemented by one or more two-tube heat exchangers, one or more shell-and-tube heat exchangers, one or more tube-in-tube heat exchangers, one or more plate heat exchangers, and / or one or more other suitable heat exchangers. The first heat exchanger 212 may be located in any suitable location in the gas turbine engine 106 (e.g., under the shroud, mounted on the engine, etc.) and / or in the aircraft 100 (e.g., in one or more wings of the aircraft 100, in the fuselage of the aircraft 100, etc.). In some examples, the first heat exchanger 212 is additively manufactured.

[0030] Hydraulic system 234 can be composed of Figure 1 The aircraft hydraulic system 110 and / or Figure 1 The hydraulic systems 110 and 114 are implemented using one or both of the engine hydraulic systems 114. In some such examples, the hydraulic systems 110 and 114 are in fluid communication. That is, in some examples, the hydraulic systems 110 and 114 include a common (e.g., shared, etc.) hydraulic fluid received by the second inlet 228 of the first heat exchanger 212. Figure 2A In the example shown, the hydraulic system 234 includes an example hydraulic bypass 236. Figure 2A In the example shown, hydraulic bypass 236 enables a portion of the hydraulic fluid exiting the first heat exchanger 212 via the second outlet 232 to be recirculated to the second inlet 228 and cooled again by the first heat exchanger 212. In some examples, the hydraulic fluid flow through hydraulic bypass 236 can be regulated by a hydraulic flow control valve (not shown). In some examples, hydraulic bypass 236 may not be present. In some examples, the hydraulic fluid flow through hydraulic bypass 236 can be in the opposite direction (e.g., recirculation).

[0031] After leaving the first heat exchanger 212, the fuel enters the second heat exchanger 214. Heat is exchanged between the fuel and the fluid associated with the secondary heat source 218 within the second heat exchanger 214, which heats the fuel and cools the fluid associated with the secondary heat source 218. After the heat exchange, the fuel exits the second heat exchanger 214. The second heat exchanger 214 may be implemented by one or more two-tube heat exchangers, one or more shell-and-tube heat exchangers, one or more tube-in-tube heat exchangers, and / or one or more plate heat exchangers.

[0032] In some examples, to regulate the amount of heat transferred to the fuel by the second heat exchanger 214, the fuel distribution management circuit 108 actuates the heat exchanger bypass valve 217 to regulate the relative portions of fuel passing through the second heat exchanger 214 and the relative portions of fuel passing through the heat exchanger bypass 216. In some examples, the fuel distribution management circuit 108 may control the heat exchanger bypass valve 217 such that the fuel leaving the second heat exchanger 214 is in a gaseous and / or supercritical state (e.g., hydrogen leaving the second heat exchanger 214 is gaseous hydrogen, hydrogen leaving the second heat exchanger 214 is supercritical hydrogen, etc.). In some examples, the supercritical and / or gaseous phase of the fuel facilitates fuel metering by the FMV 220. In some examples, the direct combustion of cryogenic liquid hydrogen can create a large temperature difference (e.g., temperature gradient, temperature deviation, temperature increment, etc.) between the inlet and outlet of the combustion section 224, which can damage the combustion section 224 and / or reduce its efficiency. In some examples, the second heat exchanger 214 is not present. In some such examples, the fuel in the first fuel distribution system 200 is heated only by the first heat exchanger 212 (e.g., by hydraulic fluid from the hydraulic system 234).

[0033] Secondary heat source 218 can be obtained through... Figure 1 The secondary heat source 218 is implemented by the airflow from the gas turbine engine 106. For example, the secondary heat source 218 may be the exhaust flow from the compressor of the gas turbine engine 106, the exhaust flow from the turbine of the gas turbine engine 106, and / or the exhaust flow leaving the gas turbine engine 106. Additionally or alternatively, the secondary heat source 218 may be from... Figure 1 The flow and / or origin of the surrounding environment of the aircraft 100 Figure 1 The lubricant flow of the lubrication and / or cooling system of the gas turbine engine 106 (e.g., a system for cooling and lubricating the bearings of the gas turbine engine 106, etc.). Additionally or alternatively, the secondary heat source 218 may be a waste heat recovery system, a fuel cell, an auxiliary power unit, an electric heater, and / or a combustion section 224.

[0034] exist Figure 2AIn the example shown, in the first fuel distribution system 200, the first heat exchanger 212 is located upstream of the second heat exchanger 214. That is, fuel leaving the cryogenic fuel tank 104 is first heated in the first heat exchanger 212 (e.g., by hydraulic fluid from the hydraulic system 234, etc.) and then heated by the second heat exchanger 214 (e.g., by the secondary heat source 218, etc.). In some examples, the configuration of the first fuel distribution system 200 (e.g., the order of the heat exchangers 212, 214, etc.) improves the efficiency of the first heat exchanger 212. For example, the efficiency of a heat exchanger is proportional to the temperature difference of the fluid flowing through the heat exchanger (e.g., incremental temperature, temperature difference, etc.). In some examples, if the secondary heat source 218 is a heated airflow from the gas turbine engine 106 (e.g., exhaust flow, etc.), the temperature of the heated hydraulic fluid entering the first heat exchanger 212 is substantially lower than the heat from the secondary heat source 218. In some such examples, the upstream positioning of the first heat exchanger 212 relative to the second heat exchanger 214 increases the temperature difference between the hydraulic fluid and the fuel in the first heat exchanger 212. This increased thermal difference in the fluid within the first heat exchanger 212 improves its efficiency.

[0035] The heating of fuel by the first heat exchanger 212 reduces the design requirements of the second heat exchanger 214. In some such examples, the presence of the first heat exchanger 212 reduces the size and weight requirements of the second heat exchanger 214. Furthermore, in some examples, the reduced design requirements of the second heat exchanger 214 decrease the amount of exhaust flow required from the secondary heat source 218, allowing the exhaust flow to be used for other purposes of the aircraft 100 (e.g., operation of the auxiliary gearbox, de-icing, cabin pressurization, etc.) and / or to be avoided from siphoning from the gas turbine engine 106, which improves the efficiency of the gas turbine engine 106. In some examples, the first heat exchanger 212 also reduces (e.g., eliminates, mitigates, etc.) the need for additional dedicated heat exchangers for cooling the hydraulic fluids of the hydraulic system 234, which reduces the weight of the aircraft 100. It should be understood that the first heat exchanger 212 and the first fuel distribution system 200 can be used to manage the thermal state of the fuel entering the combustion section 224 and the hydraulic fluids of the hydraulic system 234.

[0036] exist Figure 2AIn the example shown, the first fuel distribution system 200 includes an example system sensor 238. The system sensor 238 generates outputs associated with the operation of the first fuel distribution system 200. For example, the system sensor 238 may include a temperature sensor that generates an output associated with the temperature of fuel entering the first heat exchanger 212 via the first inlet 226 and / or the temperature of hydraulic fluid entering the first heat exchanger 212 via the second inlet 228. Additionally or alternatively, the system sensor 238 may include a flow rate sensor (e.g., a flow meter, etc.) associated with the flow rate of hydraulic fluid through and / or flowing through the first heat exchanger 212. In other examples, the system sensor 238 may include additional sensors for measuring information related to the first fuel distribution system 200 and / or the aircraft containing the first fuel distribution system 200 (e.g., [missing information]). Figure 1 Other parameters related to the aircraft 100, etc. For example, system sensor 238 can measure the position of one or more valves of hydraulic system 234 and / or first fuel distribution system 200, power setting of gas turbine engine 106, altitude of aircraft 100, fuel density, fuel pressure, etc.

[0037] Figure 2B It can be used for implementation Figure 1 A schematic diagram of an example of a second fuel distribution system 240, denoted as fuel distribution system 102. The second fuel distribution system 240 includes... Figure 1 and Figure 2A Cryogenic fuel tank 104 Figure 2A Low-pressure (LP) pump 204, Figure 2A First motor 206, Figure 2A First high-pressure (HP) pump 208, Figure 2A The second motor 210, Figure 2A First heat exchanger 212, Figure 2A Second heat exchanger 214 Figure 2A The heat exchanger bypass 216, and Figure 2A Heat exchanger bypass valve 217, Figure 2A Fuel metering valve 220 (FMV), Figure 2A Nozzle 222 and Figure 2A Combustion section 224. Figure 2B In the example shown, the first heat exchanger 212 is fluidly connected to Figure 2A Hydraulic system 234 and Figure 2A Hydraulic bypass 236. In some examples, the second fuel distribution system 240 may include additional components such as a throttle valve, an additional pump, an additional motor, and a shut-off overspeed valve (SOOV). Figure 2B In the example shown, the second fuel distribution system 240 includes system sensor 238.

[0038] The second fuel distribution system 240 is similar to Figure 2A The first fuel distribution system 200, except that the first heat exchanger 212 is located downstream of the second heat exchanger 214 (e.g., the second heat exchanger 214 is located upstream of the first heat exchanger 212, etc.). In Figure 2B In the example shown, fuel leaving HP pump 208 enters the second heat exchanger 214 and is thereby heated. Figure 2B In the example shown, after leaving the second heat exchanger 214, fuel flows into the first inlet 226 of the first heat exchanger 212 and exits via the first outlet 230. If the secondary heat source 218 entering the second heat exchanger 214 is colder than the hydraulic fluid entering the second inlet 228, the second fuel distribution system 240 can be more efficient than... Figure 2A The first fuel distribution system 200 is more efficient. It should be understood that the first heat exchanger 212 and the second fuel distribution system 240 can be used to manage the thermal state of the fuel entering the combustion section 224 and the hydraulic fluid of the hydraulic system 234.

[0039] Figure 3 It can be used for implementation Figure 1 A schematic diagram of an example third fuel distribution system 300 of the fuel distribution system 102. The third fuel distribution system 300 includes... Figure 1-2B Cryogenic fuel tank 104 Figure 2A and Figure 2B Low-pressure (LP) pump 204, Figure 2A and Figure 2B First motor 206, Figure 2A and Figure 2B First high-pressure (HP) pump 208, Figure 2A and Figure 2B The second motor 210, Figure 2A and Figure 2B First heat exchanger 212, Figure 2A and Figure 2B Second heat exchanger 214 Figure 2A and Figure 2B The heat exchanger bypass 216, and Figure 2A and Figure 2B Heat exchanger bypass valve 217, Figure 2A and Figure 2B Fuel metering valve 220 (FMV), Figure 2A And nozzle 222 in Figure 2B and Figure 2A and Figure 2B Combustion section 224. Figure 3 In the example shown, the second heat exchanger 214 is fluidly connected to Figure 2A Hydraulic system 234 and Figure 2AHydraulic bypass 236. In some examples, the third fuel distribution system 300 may include additional components such as a throttle valve, an additional pump, an additional motor, and a shut-off overspeed valve (SOOV).

[0040] exist Figure 3 In the example shown, the third fuel distribution system 300 includes a third heat exchanger 301. Figure 3 In the example shown, the third heat exchanger 301 includes a third inlet 304, a fourth inlet 306, a third outlet 308, and a fourth outlet 310. Figure 3 In the example shown, the third heat exchanger 301 is connected to the second hydraulic system 311 and the second hydraulic bypass 312. Figure 3 In the example shown, the third inlet 304 is connected to the first outlet 230 of the first heat exchanger 212. Figure 3 In the example shown, the third outlet 308 is connected to the second heat exchanger 214 and the heat exchanger bypass valve 217. Figure 3 In the example shown, the fourth inlet 306 and the fourth outlet 310 are connected to the second hydraulic system 311 and the second hydraulic bypass 312. In some examples, the first hydraulic system 234 is... Figure 1 The engine hydraulic system 114, and the second hydraulic system 311 is Figure 1 The aircraft hydraulic system 110. In other examples, the first hydraulic system 234 is... Figure 1 The aircraft hydraulic system 110, and the second hydraulic system 311 is Figure 1 The engine hydraulic system 114.

[0041] During operation, fuel from HP pump 208 enters the first heat exchanger 212 via first inlet 226, and hydraulic fluid from hydraulic system 234 enters the first heat exchanger 212 via second inlet 228. Heat is exchanged between the hydraulic fluid and fuel within the first heat exchanger 212, which cools the hydraulic fluid and heats the fuel. After the heat exchange, the fuel exits the first heat exchanger 212 via first outlet 230, and the hydraulic fluid exits the first heat exchanger 212 via second outlet 232. After exiting the first heat exchanger 212, the fuel sequentially flows into a third heat exchanger 301, and hydraulic fluid from the second hydraulic system 311 enters the third heat exchanger 301, which cools the hydraulic fluid and heats the fuel. After exiting the third heat exchanger 301 via third outlet 308, the fuel flows into the second heat exchanger 214. The third heat exchanger 301 may be implemented by one or more twin-tube heat exchangers, one or more shell-and-tube heat exchangers, one or more tube-in-tube heat exchangers, and / or one or more plate heat exchangers. In some examples, the third heat exchanger 301 may be implemented as a heat exchanger of the same type as the first heat exchanger 212 and / or the second heat exchanger 214. In some examples, some or all of the heat exchangers 212, 214, and 301 are additively manufactured.

[0042] exist Figure 3 In the example shown, the third heat exchanger 301 is arranged sequentially with the first heat exchanger 212. In other examples, the third fuel distribution system 300 is arranged in parallel with the first heat exchanger 212. For example, (1) the first inlet 226 and the third inlet 304 may be connected to the HP pump 208, and (2) the first outlet 230 and the third outlet 308 may be connected to the second heat exchanger 214, such that fuel of the third fuel distribution system 300 flows in parallel through the heat exchangers 212 and 301. In some such examples, the portion of fuel flowing through the first heat exchanger 212 and the third heat exchanger 301 may be controlled via a control valve. In some such examples, the fuel distribution management circuit 108 may determine the flow portion through the first heat exchanger 212 and the third heat exchanger 301. In some such examples, the fuel distribution management circuit 108 can determine the relative portions of the first heat exchanger 212 and the third heat exchanger 301 based on the hydraulic systems 234, 311 (e.g., the dimensions of the hydraulic systems 234, 311, the current temperature of the hydraulic fluid in the hydraulic systems 234, 311, the volume of the hydraulic fluid in the hydraulic systems 234, 311, etc.). It should be understood that the first heat exchanger 212, the third heat exchanger 301, and the third fuel distribution system 300 can be used to manage the thermal state of the fuel entering the combustion section 224 and the hydraulic fluid in the hydraulic systems 234, 311.

[0043] exist Figure 3 In the example shown, the third fuel distribution system 300 includes an example sensor 314, which, unless otherwise described, is similar to... Figure 2A and Figure 2B The system sensor 238. For example, sensor 314 generates outputs associated with the operation of the fuel distribution system 300 (e.g., fuel temperature, hydraulic fluid flow rate, etc.). In some examples, sensor 314 may include a sensor that measures the flow rate and / or temperature of hydraulic fluid flowing through a third heat exchanger 301 associated with the second heat exchanger 214.

[0044] Figure 4 It can be used for implementation Figure 1 A schematic diagram of an example of a fourth fuel distribution system 400, denoted as fuel distribution system 102. The fourth fuel distribution system 400 includes... Figure 1-3 Cryogenic fuel tank 104 Figure 2A-3 Low-pressure (LP) pump 204, Figure 2A-3 First motor 206, Figure 2A-3 First high-pressure (HP) pump 208, Figure 2A-3 The second motor 210, Figure 2A-3 Fuel metering valve 220 (FMV), Figure 2A-3 The nozzle 222 and the gas turbine engine 106 Figure 2A-3 Combustion section 224. Figure 4 In the example shown, the fourth fuel distribution system 400 includes a thermal management system 402, which includes a heat transfer bus 403, a pump 404, a first heat exchanger 406, a second heat exchanger 408, a heat exchanger bypass 409, a bypass valve 410, and a third heat exchanger 412. Figure 4 In the example shown, the second heat exchanger 408 is from Figure 2A-3 The secondary heat source 218 receives heat.

[0045] The thermal management system 402 is used to support Figure 1 aircraft 100 and / or Figure 1 A thermal management system 402 is a fluid system that transfers heat between fluids operating in a gas turbine engine 106. In some examples, some or all components of the thermal management system 402 are located within the gas turbine engine 106. For example, some or all components of the thermal management system 402 may be located within the casing and / or nacelle of the gas turbine engine 106. In other examples, the thermal management system 402 may be located in... Figure 1 The location on the aircraft 100 (e.g., in the fuselage, adjacent to the fuel tank, in the wing, etc.). Figure 4 In the example shown, the thermal management system 402 is in Figure 2A-3The thermal management system 402 transfers heat between the hydraulic fluid of the hydraulic system 234, the fuel in the cryogenic fuel tank 104, and the secondary heat source 218. In other examples, the thermal management system 402 may also transfer heat between other fluids and / or components of the aircraft 100 and / or the gas turbine engine 106 (e.g., the gas turbine engine's lubrication system, the gas turbine engine's exhaust flow, the gas turbine engine's discharge flow, etc.).

[0046] During operation, the working fluid of the thermal management system 402 flows to heat exchangers 406, 408, and 412 via a heat transfer bus 403. The heat transfer bus 403 includes one or more fluid conduits through which the working fluid flows. As the working fluid flows through the respective heat exchangers, heat is added to the working fluid via the first heat exchanger 406 and the second heat exchanger 408, and removed from the working fluid via the third heat exchanger 412. The working fluid of the thermal management system 402 and the fluid of the heat transfer bus 403 can be supercritical carbon dioxide (sCO2), nitrogen, oil, liquid helium, helium-xenon, and / or similar fluids. Figure 4 In the example shown, the working fluid is driven by pump 404 via heat transfer bus 403. Pump 404 may be electrically driven and / or driven via an auxiliary gearbox of gas turbine engine 106. In some examples, pump 404 is an impeller (e.g., a single centrifugal compressor, etc.). In other examples, pump 404 may be implemented by any other suitable type of pump (e.g., cycloidal pump, impeller pump, etc.) and / or compressor (e.g., axial flow pump, multistage centrifugal compressor, rotary screw compressor, etc.). In some examples, thermal management system 402 may include an additional pump similar to a compressor.

[0047] Heat exchangers 406, 408, and 412 are similar Figure 2A-3 Heat exchangers 212 and 214, unless otherwise specified. For example, heat exchangers 406, 408, and 412 can be implemented as one or more two-tube heat exchangers, one or more shell-and-tube heat exchangers, one or more tube-in-tube heat exchangers, and / or one or more plate heat exchangers. In some examples, heat exchangers 406, 408, and 412 can be implemented by the same type of heat exchanger. In other examples, some or all of heat exchangers 406, 408, and 412 can be implemented by heat exchangers of different types.

[0048] exist Figure 4 In the example shown, the first heat exchanger 406 includes a first inlet 414, a second inlet 416, a first outlet 418, and a second outlet 420. Figure 4 In the example shown, the first inlet 414 and the first outlet 418 are connected to the heat transfer bus 403. Figure 4 In the example shown, the second inlet 416 and the second outlet 420 are connected to Figure 2A-3The system comprises a hydraulic system 234 and a hydraulic bypass 236. During operation, working fluid from the heat transfer bus 403 enters the first heat exchanger 406 via a first inlet 414, and hydraulic fluid from the hydraulic system 234 enters the first heat exchanger 406 via a second inlet 416. Heat is exchanged between the hydraulic fluid and the working fluid within the first heat exchanger 406, which cools the hydraulic fluid and heats the working fluid. After exchanging heat with the hydraulic fluid, the working fluid exits the first heat exchanger 406 via a first outlet 418, and the hydraulic fluid exits the first heat exchanger 406 via a second outlet 420. Figure 4 In the example shown, the heat transfer bus 403 does not include a bypass that allows the working fluid of the heat transfer bus 403 to bypass the first heat exchanger 406. In other examples, the heat transfer bus 403 includes a bypass to allow some or all of the working fluid to bypass the first heat exchanger 406. In other examples, the bypass includes a valve to control a portion of the flow through the first heat exchanger 406 and the bypass. In some such examples, the position of the valve is regulated by fluid from the heat transfer bus 403, the hydraulic system 234, and / or another suitable control system. Additionally or alternatively, the position of the valve is positioned by a motor or electromagnetic actuator. Additionally or alternatively, the valve is... Figure 1 The fuel distribution management circuit 108 is controlled.

[0049] The second heat exchanger 408 receives working fluid from the heat transfer bus 403 and heat from the secondary heat source 218. Heat is exchanged within the second heat exchanger 408 between the fluid associated with the secondary heat source 218 and the working fluid, which heats the working fluid. In the illustrated example, the heat exchanger bypass 409 allows the working fluid (e.g., some working fluid, all working fluid, etc.) to bypass the second heat exchanger 408. In some examples, the relative portions of the working fluid flowing through the second heat exchanger 408 and the heat exchanger bypass 409 can be... Figure 1 The fuel distribution management circuit 108 is regulated.

[0050] The third heat exchanger 412 receives working fluid from the heat transfer bus 403 and fuel from the HP pump 208. The third heat exchanger 412 transfers heat between the fuel and the working fluid, heating the fuel and cooling the working fluid. After heat exchange within the third heat exchanger 412, the fuel flows to the FMV 220, and the working fluid returns to the heat transfer bus 403. Figure 4In the example shown, the third heat exchanger 412 does not include a bypass conduit that allows fuel from the cryogenic fuel tank 104 to bypass the third heat exchanger 412 or a bypass conduit that allows the working fluid of the heat transfer bus 403 to bypass the third heat exchanger 412. In other examples, the third heat exchanger 412 may include a bypass to allow some or all of the fuel from the cryogenic fuel tank 104 to bypass the third heat exchanger 412 and / or to allow some or all of the working fluid to bypass the third heat exchanger 412. It should be understood that heat exchangers 406, 408, 412 and the fourth fuel distribution system 400 can be used to manage the thermal state of fuel entering the combustion section 224 and hydraulic fluid entering the hydraulic system 234.

[0051] exist Figure 4 In the example shown, the fourth fuel distribution system 400 includes an example sensor 422, which, unless otherwise described, is similar to... Figure 2A and Figure 2B System sensor 238 and Figure 3 Sensor 314. For example, sensor 422 generates outputs associated with the operation of fuel distribution system 400 (e.g., fuel temperature, hydraulic fluid flow rate, etc.). In some examples, sensor 422 may include sensors that measure the flow rate and / or temperature of the working fluid at various locations in the heat transfer bus 403.

[0052] Figure 5 yes Figure 1 A block diagram of an example embodiment of the fuel distribution management circuit 108, used to regulate fuel distribution management circuitry. Figure 1 Fuel distribution system 102, Figure 2A First fuel distribution system 200 Figure 2B Second fuel distribution system 240, Figure 3 The third fuel distribution system 300 and / or Figure 4 The fourth fuel distribution system 400 controls the fuel flow rate, as well as the fuel and... Figure 1 Heat transfer between the hydraulic fluids in hydraulic systems 110 and 114. For example, fuel distribution management circuit 108 can be used to determine... Figure 2A-3 Heat exchanger bypass valve 217 and / or Figure 4 The position of bypass valve 410. Figure 5 In the example shown, the fuel distribution management circuit 108 includes a sensor interface circuit 501, a heat exchange rate determiner circuit 502, a bypass ratio determiner circuit 504, and a valve interface circuit 506.

[0053] Figure 5The fuel distribution management circuit 108 can be instantiated (e.g., instantiated, implemented, materialized, enforced, etc.) by a programmable circuit (e.g., a central processing unit (CPU)) that executes the first instruction. Additionally or alternatively, Figure 5 The fuel distribution management circuit 108 can be instantiated (e.g., instantiated, implemented, materialized, enforced, etc.) by (i) an application-specific integrated circuit (ASIC) and / or (ii) a field-programmable gate array (FPGA) constructed and / or configured to perform an operation corresponding to the first instruction in response to the execution of the second instruction. It should be understood that, therefore, Figure 5 Some or all of the circuits can be instantiated at the same or different times. For example, Figure 5 Some or all of the circuitry can be instantiated in one or more threads that execute concurrently on hardware and / or serially on hardware. Furthermore, in some examples, Figure 5 Some or all of the circuitry can be implemented by microprocessor circuitry that executes instructions and / or FPGA circuitry that performs operations to implement one or more virtual machines and / or containers.

[0054] Sensor interface circuit 501 communicates with a fuel distribution system (e.g., Figure 2A-3 The fuel distribution system 200, 240, 300, etc.) accesses (e.g., receives, retrieves, etc.) sensor data associated with its sensors. For example, sensor interface circuit 501 can access (e.g., receive, retrieve, etc.) sensor data from the sensors associated with it. Figure 2A and Figure 2B System sensor 238, Figure 3 Sensor 314 and / or Figure 4 Sensor 422 receives sensor output. In some examples, sensor interface circuitry 501 can convert the accessed sensor output from a machine-readable format (e.g., voltage, current, etc.) to a human-readable format (e.g., integer, floating-point number, etc.). In some examples, sensor interface circuitry 501 is instantiated by and / or configured by programmable circuitry that executes sensor interface instructions as described above. Figure 6 The operations shown in the flowchart are those operations.

[0055] In some examples, the fuel distribution management circuit 108 includes means for interfacing with a sensor. For example, the means for interfacing with the sensor may be implemented by a heat exchange rate determiner circuit 502. In some examples, the sensor interface circuit 501 may be instantiated by programmable circuitry, such as… Figure 7 Example programmable circuit 712. For example, sensor interface circuit 501 can be instantiated as a microprocessor that executes machine-executable instructions, such as those provided by [unclear text - likely a microprocessor or microprocessor]. Figure 6The instructions implemented in at least block 601. In some examples, sensor interface circuitry 501 may be instantiated by hardware logic circuitry, which may be implemented by ASIC, XPU, or FPGA circuitry configured and / or constructed to perform operations corresponding to machine-readable instructions. Additionally or alternatively, sensor interface circuitry 501 may be instantiated by any other combination of hardware, software, and / or firmware. For example, sensor interface circuitry 501 may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and / or integrated analog and / or digital circuitry, FPGA, ASIC, XPU, comparator, operational amplifier, logic circuitry, etc.) configured and / or constructed to perform some or all of the machine-readable instructions and / or perform some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other configurations are equally applicable.

[0056] Heat exchange rate determiner circuit 502 determines the hydraulic fluid and another fluid (e.g., Figure 2A-3 The fuel in fuel distribution systems 200, 240, and 300 Figure 4 The heat exchange rate between the working fluid (e.g., in the fourth fuel distribution system 400) and other fluids. For example, the heat exchange rate determiner circuit 502 can determine the heat exchange rate based on sensor data accessed by the sensor interface circuit 501. Figure 2A , 2B The heat exchange rate between fuel and hydraulic fluid in the first heat exchanger 212 is determined by circuit 502. In some such examples, the heat exchange rate determiner circuit 502 can determine the heat exchange rate in the first heat exchanger 212 based on the flow rate of fuel entering the first inlet 226 of the first heat exchanger 212, the flow rate of hydraulic fluid entering the second inlet 228 of the first heat exchanger 212, the specific heat of the fuel, the specific heat of the hydraulic fluid, the geometry of the first heat exchanger 212, and the temperature difference between the hydraulic fluid and the fuel. In other examples, the heat exchange rate determiner circuit 502 can determine... Figure 4 The heat exchange rate between the hydraulic fluid and the working fluid in the first heat exchanger 406. In some such examples, the heat exchange rate determiner circuit 502 can determine the heat exchange rate in the first heat exchanger 406 based on the flow rate of the working fluid entering the first inlet 414 of the first heat exchanger 406, the flow rate of the hydraulic fluid entering the second inlet 416 of the first heat exchanger 406, the specific heat of the working fluid, the specific heat of the hydraulic fluid, the geometry of the first heat exchanger 406, and the temperature difference (e.g., temperature difference, etc.) between the hydraulic fluid and the working fluid.

[0057] In some examples, the heat exchange rate determiner circuit 502 can determine the heat exchange rate in multiple heat exchangers associated with the heat exchange between fuel and hydraulic fluid. For example, the heat exchange rate determiner circuit 502 can determine... Figure 3 The total heat exchange rate in the first heat exchanger 212 and the third heat exchanger 301 in the third fuel distribution system 300. In some examples, the heat exchange rate determiner circuit 502 is instantiated by a programmable circuit that executes heat exchange rate determiner instructions and / or configured to execute as described by... Figure 6 The operations shown in the flowchart are those operations.

[0058] In some examples, the fuel distribution management circuit 108 includes means for determining the heat exchange rate between the hydraulic fluid and the fuel. For example, determining the heat exchange rate between the hydraulic fluid and the fuel can be implemented by a heat exchange rate determiner circuit 502. In some examples, the heat exchange rate determiner circuit 502 can be instantiated by a programmable circuit, such as... Figure 7 Example programmable circuit 712. For example, heat exchange rate determiner circuit 502 can be instantiated by a microprocessor that executes machine-executable instructions, such as by... Figure 6 The instructions implemented by at least block 602. In some examples, the hot-swap rate determiner circuit 502 may be instantiated by hardware logic circuitry, which may be implemented by ASIC, XPU, or FPGA circuitry configured and / or constructed to perform operations corresponding to machine-readable instructions. Additionally or alternatively, the hot-swap rate determiner circuit 502 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the hot-swap rate determiner circuit 502 may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and / or integrated analog and / or digital circuitry, FPGA, ASIC, XPU, comparator, operational amplifier, logic circuitry, etc.) configured and / or constructed to perform some or all of the machine-readable instructions and / or perform some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other configurations are equally applicable.

[0059] The bypass ratio determiner circuit 504 determines the bypass ratio of the second heat exchanger that transfers heat between the secondary heat source and the first fluid. For example, the bypass ratio determiner circuit 504 can determine the flow rate through the second heat exchanger. Figure 2A-3 The fuel portion of the second heat exchanger 214 and the flow Figure 2A-3The bypass ratio is determined by the corresponding portion of the fuel in the heat exchanger bypass 216 (e.g., the ratio of the mass flow rate of the fuel passing through the second heat exchanger to the mass flow rate of the fuel flowing through the heat exchanger bypass 216). In some examples, the bypass ratio determiner circuit 504 can determine the bypass ratio of the second heat exchanger 214 based on the heat exchange rate of the first heat exchanger 212 determined by the heat exchange rate determiner circuit 502, the mass flow rate of the fuel passing through the second heat exchanger 214, the characteristics of the secondary heat source (e.g., the mass flow rate of the secondary heat source entering the secondary heat source 218, the specific heat of the secondary heat source 218, the temperature of the secondary heat source 218, etc.), the temperature of the fuel entering the second heat exchanger 214, and the desired input conditions of the fuel entering the combustion section 224. For example, the bypass ratio of the second heat exchanger 214 can be determined such that the secondary heat source 218 heats the fuel to a target temperature and / or to a gaseous or supercritical state. In other words, the bypass ratio determiner circuit 504 can determine the bypass ratio of the second heat exchanger 214 such that the total amount of heat transferred to the fuel by the heat exchangers 212, 214 heats the fuel to the target temperature and / or to the desired state (e.g., gaseous, supercritical, etc.).

[0060] In other examples, the bypass ratio determiner circuit 504 can determine the portion of the working fluid flowing through the second heat exchanger 408 and the corresponding portion of the working fluid flowing through the heat exchanger bypass 409 (e.g., the ratio of the mass flow rate of the working fluid through the second heat exchanger 408 to the mass flow rate of the working fluid flowing through the heat exchanger bypass 409, etc.). In some examples, the bypass ratio determiner circuit 504 can determine a bypass ratio such that the temperature of the working fluid causes the fuel to reach a target temperature and / or condition when it leaves the third heat exchanger 412. For example, the bypass ratio determiner circuit 504 can determine a bypass ratio such that the fuel has a target temperature (e.g., the vaporization temperature of gaseous hydrogen at system pressure, the critical temperature of hydrogen, etc.) and a target phase (e.g., hydrogen is vapor, hydrogen is in a supercritical state, etc.).

[0061] In some examples, the bypass ratio determiner circuit 504 can determine the bypass ratio of the second heat exchanger 408 based on the heat exchange rate of the first heat exchanger 406 determined by the heat exchange rate determiner circuit 502, the mass flow rate of the working fluid through the second heat exchanger 408, the specific heat of the working fluid, the characteristics of the secondary heat source (e.g., the mass flow rate of the secondary heat source entering the secondary heat source 218, the specific heat of the secondary heat source 218, the temperature of the secondary heat source, etc.), the temperature of the working fluid entering the second heat exchanger 408, the characteristics of the third heat exchanger 412 (e.g., the characteristics of the fuel entering the third heat exchanger 412, the geometry of the third heat exchanger 412, etc.), and the desired input conditions of the fuel entering the combustion section 224. In some examples, the bypass ratio determiner circuit 504 is instantiated by a programmable circuit that executes bypass ratio determiner instructions and / or configured to execute as specified by the heat exchange rate determiner circuit 502. Figure 6 The operations shown in the flowchart are those operations.

[0062] In some examples, the fuel distribution management circuit 108 includes means for determining the bypass ratio of the heat exchanger. For example, the means for determination may be implemented by a bypass ratio determiner circuit 504. In some examples, the bypass ratio determiner circuit 504 may be instantiated by a programmable circuit, such as... Figure 7 Example programmable circuit 712. For example, bypass ratio determiner circuit 504 can be instantiated by a microprocessor that executes machine-executable instructions, such as by... Figure 6 The bypass ratio determiner circuit 504 implements at least those instructions. In some examples, the bypass ratio determiner circuit 504 may be instantiated by hardware logic circuitry, which may be implemented by ASIC, XPU, or FPGA circuitry configured and / or constructed to perform operations corresponding to machine-readable instructions. Additionally or alternatively, the bypass ratio determiner circuit 504 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the bypass ratio determiner circuit 504 may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and / or integrated analog and / or digital circuitry, FPGA, ASIC, XPU, comparator, operational amplifier, logic circuitry, etc.) configured and / or constructed to perform some or all of the machine-readable instructions and / or perform some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other configurations are equally applicable.

[0063] Valve interface circuit 506 and Figure 2A-3 Heat exchanger bypass valve 217, Figure 2A-4 Hydraulic bypass 236, Figure 3 Second hydraulic bypass 312 and / or Figure 4 The bypass valve 410 interface. For example, valve interface circuit 506 actuates the value associated with the second heat exchanger 214 based on a determined bypass ratio. For example, valve interface circuit 506 can actuate... Figure 2A-3 The heat exchanger bypass valve 217 ensures that the flow rate of fuel through the second heat exchanger 214 and the heat exchanger bypass 216 conforms to a predetermined bypass ratio. In some examples, the valve interface circuit 506 can be actuated. Figure 2A-3 The heat exchanger bypass valve 217 ensures that the flow rate of the working fluid through the second heat exchanger 408 and the heat exchanger bypass 409 conforms to a determined bypass ratio. In some examples, the valve interface circuit 506 can be connected via an electrical signal, an optical signal, or via a hydraulic system (e.g., via...). Figure 1One or more transmissions (such as hydraulic signals, pneumatic signals, etc.) in hydraulic systems 110, 114 are interfaced with valves. In some examples, valve interface circuit 506 is instantiated by programmable circuitry that executes valve interface instructions and / or configured to execute such instructions as provided by... Figure 6 The operations shown in the flowchart are those operations.

[0064] In some examples, the fuel distribution management circuit 108 includes means for interfacing with a bypass valve. For example, interfacing with the bypass valve may be implemented by valve interface circuitry 506. In some examples, valve interface circuitry 506 may be instantiated by programmable circuitry, such as… Figure 7 Example programmable circuit 712. For example, valve interface circuit 506 can be instantiated by a microprocessor that executes machine-executable instructions, such as by... Figure 6 The instructions implemented in at least blocks 606 and 608. In some examples, valve interface circuit 506 may be instantiated by hardware logic circuitry, which may be implemented by ASIC, XPU, or FPGA circuitry configured and / or constructed to perform operations corresponding to machine-readable instructions. Additionally or alternatively, valve interface circuit 506 may be instantiated by any other combination of hardware, software, and / or firmware. For example, valve interface circuit 506 may be implemented by at least one or more hardware circuits (e.g., processor circuitry, discrete and / or integrated analog and / or digital circuitry, FPGA, ASIC, XPU, comparator, operational amplifier, logic circuitry, etc.) configured and / or constructed to perform some or all of the machine-readable instructions and / or perform some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other configurations are equally applicable.

[0065] Although Figure 5 The implementation is shown in the figure. Figure 1 An example of the fuel distribution management circuit 108, but Figure 5 One or more elements, processes, and / or devices shown may be combined, divided, rearranged, omitted, eliminated, and / or implemented in any other way. Furthermore, the sensor interface circuit 501, heat exchange rate determiner circuit 502, bypass ratio determiner circuit 504, valve interface circuit 506, and / or more generally, Figure 5The example fuel distribution management circuit 108 can be implemented by hardware alone or by hardware in combination with software and / or firmware. Therefore, for example, any of the sensor interface circuit 501, the example heat exchange rate determiner circuit 502, the bypass ratio determiner circuit 504, the valve interface circuit 506, and / or more generally, the example fuel distribution management circuit 108 can be implemented by programmable circuitry in combination with machine-readable instructions (e.g., firmware or software), processor circuitry, analog circuitry, digital circuitry, logic circuitry, programmable processors, programmable microcontrollers, graphics processing units (GPUs), digital signal processors (DSPs), ASICs, programmable logic devices (PLDs), and / or field-programmable logic devices (FPLDs) (e.g., FPGAs). Furthermore, Figure 5 Example fuel distribution management circuit 108 may include as Figure 5 One or more elements, processes, and / or devices that supplement or substitute for the elements, processes, and / or devices shown, and / or may include more than one of any or all of the elements, processes, and devices shown.

[0066] Figure 6 The diagram illustrates that it can be implemented and / or instantiated by programmable circuitry. Figure 5 Example machine-readable instructions and / or representations of the fuel distribution management circuit 108 can be executed by programmable circuitry to implement and / or instantiate it. Figure 5 A flowchart illustrating an example operation of the fuel distribution management circuit 108. Machine-readable instructions can be used by programmable circuits (e.g., in conjunction with the following). Figure 7 The programmable circuit 712 shown in the example programmable circuit platform 700 discussed herein executes one or more executable programs or portions of one or more executable programs, and / or may be one or more functions or portions of functions executed by the example programmable circuit (e.g., FPGA). In some examples, machine-readable instructions cause operations, tasks, etc., to be performed and / or carried out in a real-world manner in an automated manner. As used herein, “automation” means without human intervention.

[0067] The program may be embodied in instructions (e.g., software and / or firmware) stored on one or more non-transitory computer-readable and / or machine-readable storage media, such as cache memory, magnetic storage devices or disks (e.g., floppy disks, hard disk drives (HDDs), etc.), optical storage devices or optical discs (e.g., Blu-ray discs, optical discs (CDs), digital versatile discs (DVDs), etc.), redundant arrays of independent disks (RAID), registers, ROM, solid-state drives (SSDs), SSD memory, non-volatile memory (e.g., electrically erasable programmable read-only memory (EEPROM), flash memory, etc.), volatile memory (e.g., random access memory (RAM) of any type, etc.), and / or any other storage device or disk. The instructions on the non-transitory computer-readable and / or machine-readable media may be programmed and / or executed by programmable circuitry located in one or more hardware devices, but the entire program and / or portions thereof may alternatively be executed and / or instantiated and / or embodied in dedicated hardware by one or more hardware devices other than programmable circuitry. Machine-readable instructions can be distributed across multiple hardware devices and / or executed by two or more hardware devices (e.g., server and client hardware devices). For example, client hardware devices can be implemented by endpoint client hardware devices (e.g., hardware devices associated with human and / or machine users) or intermediate client hardware device gateways (e.g., radio access networks (RANs)) that facilitate communication between server and endpoint client hardware devices. Similarly, non-transitory computer-readable storage media can include one or more media. Furthermore, although references... Figure 7 The flowchart shown describes an example program, but many other methods of implementing the example fuel distribution management circuit 108 can be used alternatively. For example, the execution order of the flowchart blocks can be changed, and / or some of the described blocks can be changed, eliminated, or combined. Additionally or alternatively, any or all of the flowchart blocks can be implemented by one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, comparators, operational amplifiers (op-amps), logic circuits, etc.) configured to perform the corresponding operations without executing software or firmware. Programmable circuits can be distributed across different network locations and / or local to one or more hardware devices (e.g., single-core processors (e.g., single-core CPUs), multi-core processors (e.g., multi-core CPUs, XPUs, etc.)). For example, programmable circuits can be CPUs and / or FPGAs located in the same package (e.g., the same integrated circuit (IC) package or two or more separate housings), one or more processors in a single machine, multiple processors distributed across multiple servers in a server rack, multiple processors distributed across one or more server racks, etc., and / or any combination thereof.

[0068] Machine-readable instructions described herein may be stored in one or more of the following formats: compressed format, encrypted format, segmented format, compiled format, executable format, packaged format, etc. Machine-readable instructions as described herein may be stored as data (e.g., computer-readable data, machine-readable data, one or more bits (e.g., one or more computer-readable bits, one or more machine-readable bits, etc.), bit streams (e.g., computer-readable bit streams, machine-readable bit streams, etc.)) or data structures (e.g., as part of instructions, code, code representation, etc.) that can be used to create, manufacture, and / or produce machine-executable instructions. For example, machine-readable instructions may be segmented and stored on one or more storage devices, disks, and / or computing devices (e.g., servers) located at the same or different locations within a network or network set (e.g., in the cloud, at an edge device, etc.). Machine-readable instructions may require installation, modification, adaptation, updating, combination, supplementation, configuration, decryption, decompression, unpacking, distribution, reallocation, compilation, etc., to make them directly readable, interpretable, and / or executable by computing devices and / or other machines. For example, machine-readable instructions may be stored in multiple parts that are individually compressed, encrypted, and / or stored on separate computing devices, wherein these parts, when decrypted, decompressed, and / or combined, form a set of computer-executable and / or machine-executable instructions that, when implemented together, can form one or more functions and / or operations of a program as described herein.

[0069] In another example, machine-readable instructions may be stored in a state where they can be read by programmable circuitry, but require the addition of libraries (e.g., dynamic link libraries (DLLs)), software development kits (SDKs), application programming interfaces (APIs), etc., to execute the machine-readable instructions on a specific computing device or other device. In yet another example, the machine-readable instructions may need to be configured (e.g., storage settings, data input, recorded network addresses, etc.) before they can be executed in whole or in part. Therefore, as used herein, machine-readable, computer-readable, and / or machine-readable media may include instructions and / or programs, regardless of their specific format or state.

[0070] The machine-readable instructions described in this article can be represented by any past, present, or future instruction language, scripting language, programming language, etc. For example, machine-readable instructions can be represented using any of the following languages: C, C++, Java, C#, Perl, Python, JavaScript, Hypertext Markup Language (HTML), Structured Query Language (SQL), Swift, etc.

[0071] As mentioned above, Figure 7Example operations can be implemented using executable instructions (e.g., computer-readable and / or machine-readable instructions) stored on one or more non-transient computer-readable and / or machine-readable media. As used herein, the terms non-transient computer-readable medium, non-transient computer-readable storage medium, non-transient machine-readable medium, and / or non-transient machine-readable storage medium are explicitly defined to include any type of computer-readable storage device and / or storage disk, excluding propagated signals and transmission media. Examples of such non-transient computer-readable medium, non-transient computer-readable storage medium, non-transient machine-readable medium, and / or non-transient machine-readable storage medium include optical storage devices, magnetic storage devices, HDDs, flash memory, read-only memory (ROM), CDs, DVDs, caches, any type of RAM, registers, and / or any other storage device or storage disk, wherein information is stored for any duration (e.g., extended time period, permanent, transient, temporary buffer, and / or cached information). As used herein, the terms "non-transient computer-readable storage device" and "non-transient machine-readable storage device" are defined as including any physical (mechanical, magnetic, and / or electrical) hardware designed to retain information for a period of time, excluding propagation signals and transmission media. Examples of non-transient computer-readable storage devices and / or non-transient machine-readable storage devices include any type of random access memory, any type of read-only memory, solid-state memory, flash memory, optical discs, hard disks, disk drives, and / or redundant arrays of independent hard disks (RAID) systems. As used herein, the term "device" refers to a physical structure, such as mechanical and / or electrical equipment, hardware, and / or circuitry, which may or may not be configured and / or manufactured by computer-readable instructions, machine-readable instructions, etc., for executing computer-readable instructions and machine-readable instructions, etc.

[0072] Figure 6 This is a flowchart representing example machine-readable instructions and / or example operations 600, which can be executed, instantiated, and / or performed by programmable circuitry to regulate... Figure 1 Fuel distribution system 102, Figure 2A First fuel distribution system 200 Figure 2B Second fuel distribution system 240, Figure 3 The third fuel distribution system 300 and / or Figure 4 The fourth fuel distribution system 400 controls the fuel flow rate, as well as the fuel and... Figure 1 Heat transfer between hydraulic fluids in hydraulic systems 110 and 114.

[0073] Figure 6 Example machine-readable instructions and / or example operations 600 begin at box 601, where sensor interface circuitry 501 connects to a fuel distribution system (e.g., Figure 2A-3The fuel distribution system 200, 240, 300, etc.) accesses (e.g., receives, retrieves, etc.) sensor data associated with its sensors. For example, sensor interface circuit 501 can access (e.g., receive, retrieve, etc.) sensor data from the sensors associated with it. Figure 2A and Figure 2B System sensor 238, Figure 3 Sensor 314 and / or Figure 4 Sensor 422 receives sensor output. In some examples, sensor interface circuitry 501 can convert the accessed sensor output from a machine-readable format (e.g., voltage, current, etc.) to a human-readable format (e.g., integer, floating-point number, etc.).

[0074] At block 602, heat exchange rate determiner circuit 502 determines the heat exchange rate between the first fluid and the hydraulic fluid in the first heat exchanger based on the accessed sensor output. For example, heat exchange rate determiner circuit 502 can determine... Figure 2A , 2B The heat exchange rate between fuel and hydraulic fluid in the first heat exchanger 212 is determined by circuit 502. In some such examples, the heat exchange rate determiner circuit 502 can determine the heat exchange rate in the first heat exchanger 212 based on the flow rate of fuel entering the first inlet 226 of the first heat exchanger 212, the flow rate of hydraulic fluid entering the second inlet 228 of the first heat exchanger 212, the specific heat of the fuel, the specific heat of the hydraulic fluid, the geometry of the first heat exchanger 212, and the temperature difference between the hydraulic fluid and the fuel. In other examples, the heat exchange rate determiner circuit 502 can determine... Figure 4 The heat exchange rate between the hydraulic fluid and the working fluid in the first heat exchanger 406. In some such examples, the heat exchange rate determiner circuit 502 can determine the heat exchange rate in the first heat exchanger 406 based on the flow rate of the working fluid entering the first inlet 414 of the first heat exchanger 406, the flow rate of the hydraulic fluid entering the second inlet 416 of the first heat exchanger 406, the specific heat of the working fluid, the specific heat of the hydraulic fluid, the geometry of the first heat exchanger 406, and the temperature difference between the hydraulic fluid and the working fluid. In some examples, the heat exchange rate determiner circuit 502 can determine the heat exchange rate in multiple heat exchangers associated with the heat exchange between fuel and hydraulic fluid. For example, the heat exchange rate determiner circuit 502 can determine... Figure 3 The total heat exchange rate in the first heat exchanger 212 and the third heat exchanger 301 in the third fuel distribution system 300.

[0075] At block 604, bypass ratio determiner circuit 504 determines the bypass ratio of the second heat exchanger that transfers heat between the secondary heat source and the first fluid. For example, bypass ratio determiner circuit 504 can determine the flow rate through the second heat exchanger. Figure 2A-3 The fuel portion of the second heat exchanger 214 and the flow Figure 2A-3The corresponding portion of the fuel in the heat exchanger bypass 216 (e.g., the ratio of the mass flow rate of the fuel through the second heat exchanger to the mass flow rate of the fuel flowing through the heat exchanger bypass 216).

[0076] In some examples, the bypass ratio determiner circuit 504 can determine the bypass ratio of the second heat exchanger 214 based on the heat exchange rate of the first heat exchanger 212 determined during the execution of block 602, the mass flow rate of the fuel through the second heat exchanger 214, the characteristics of the secondary heat source (e.g., the mass flow rate of the secondary heat source entering the secondary heat source 218, the specific heat of the secondary heat source 218, the temperature of the secondary heat source 218, etc.), the temperature of the fuel entering the second heat exchanger 214, and the desired input conditions of the fuel entering the combustion section 224. For example, the bypass ratio of the second heat exchanger 214 can be determined such that the secondary heat source 218 heats the fuel to a target temperature and / or to a gaseous or supercritical state. That is, the bypass ratio determiner circuit 504 can determine the bypass ratio of the second heat exchanger 214 such that the total amount of heat transferred to the fuel by the heat exchangers 212, 214 heats the fuel to a target temperature and / or to a desired state (e.g., gas, supercritical fluid, etc.). In some such examples, the bypass ratio determiner circuit 504 can determine the bypass ratio at the liquid-to-vapor critical point of the fuel under system pressure (e.g., the liquid-to-vapor critical point of hydrogen, the liquid-to-vapor critical point of methane, etc.).

[0077] In other examples, the bypass ratio determiner circuit 504 can determine the portion of the working fluid flowing through the second heat exchanger 408 and the corresponding portion of the working fluid flowing through the heat exchanger bypass 409 (e.g., the ratio of the mass flow rate of the working fluid through the second heat exchanger 408 to the mass flow rate of the working fluid flowing through the heat exchanger bypass 409, etc.). In some examples, the bypass ratio determiner circuit 504 can determine a bypass ratio such that the temperature of the working fluid causes the fuel to reach a target temperature and / or condition when it leaves the third heat exchanger 412. In some examples, the bypass ratio determiner circuit 504 may determine the bypass ratio of the second heat exchanger 408 based on the heat exchange rate of the first heat exchanger 406 determined during the execution of block 602, the mass flow rate of the working fluid through the second heat exchanger 408, the specific heat of the working fluid, the characteristics of the secondary heat source (e.g., the mass flow rate of the secondary heat source entering the secondary heat source 218, the specific heat of the secondary heat source 218, the temperature of the secondary heat source 218, etc.), the temperature of the working fluid entering the second heat exchanger 408, the characteristics of the third heat exchanger 412 (the characteristics of the fuel entering the third heat exchanger 412, the geometry of the third heat exchanger 412, etc.), and the desired input conditions of the fuel entering the combustion section 224.

[0078] At block 606, valve interface circuit 506 actuates the value associated with the second heat exchanger 214 or 408 based on a determined bypass ratio. For example, valve interface circuit 506 can actuate... Figure 2A-3 The heat exchanger bypass valve 217 ensures that the flow rate of fuel through the second heat exchanger 214 and the heat exchanger bypass 216 conforms to a predetermined bypass ratio. In some examples, the valve interface circuit 506 can be actuated. Figure 4 The bypass valve 410 ensures that the flow rate of the working fluid through the second heat exchanger 408 and the heat exchanger bypass 409 conforms to a determined bypass ratio. At block 608, valve interface circuit 506 determines whether to continue monitoring the fuel distribution system. For example, valve interface circuit 506 may determine to continue monitoring the fuel distribution system (e.g., the first fuel distribution system 200, the second fuel distribution system 240, the third fuel distribution system 300, and / or the fourth fuel distribution system 400, etc.) based on the operation of such a fuel distribution system (e.g., continue monitoring if the fuel distribution system is still operating, etc.). Additionally or alternatively, valve interface circuit 506 may determine whether to continue monitoring or stop monitoring based on user input from the fuel distribution system and / or the operator of aircraft 100. If valve interface circuit 506 determines to continue monitoring the fuel distribution system, operation 600 returns to block 602. If valve interface circuit 506 determines not to continue monitoring the fuel distribution system (e.g., stop monitoring the fuel distribution system, etc.), operation 600 ends.

[0079] Figure 7 This is a block diagram of an example programmable circuit platform 700, which is configured to perform and / or instantiate... Figure 6 Example machine-readable instructions and / or example operations for implementation Figure 5 The fuel distribution controller circuit. The programmable circuit platform 700 can be, for example, a server, personal computer, workstation, self-learning machine (e.g., neural network), mobile device (e.g., mobile phone, smartphone, such as iPad). TM Tablet computers, personal digital assistants (PDAs), internet applications, DVD players, CD players, headphones (e.g., augmented reality (AR) headphones, virtual reality (VR) headphones, etc.) or other wearable devices, or any other type of computing and / or electronic device.

[0080] The programmable circuit platform 700 shown in the example includes programmable circuitry 712. Programmable circuitry 712 is hardware. For example, programmable circuitry 712 can be implemented by one or more integrated circuits, logic circuits, FPGAs, microprocessors, CPUs, GPUs, DSPs, and / or microcontrollers from any desired family or manufacturer. Programmable circuitry 712 can be implemented by one or more semiconductor-based (e.g., silicon-based) devices. In this example, programmable circuitry 712 implements sensor interface circuitry 501, heat exchange rate determiner circuitry 502, bypass ratio determiner circuitry 504, and valve interface circuitry 506.

[0081] The programmable circuit 712 shown in the example includes local memory 713 (e.g., cache, registers, etc.). The programmable circuit 712 of the example communicates via bus 718 with main memory 714, 716, which includes volatile memory 714 and non-volatile memory 716. Volatile memory 714 may be synchronous dynamic random access memory (SDRAM), dynamic random access memory (DRAM), etc. Dynamic Random Access Memory And / or any other type of RAM device. The non-volatile memory 716 can be implemented by flash memory and / or any other desired type of memory device. Access to the main memory 714, 716 of the illustrated examples is controlled by the memory controller 717. In some examples, the memory controller 717 can be implemented by one or more integrated circuits, logic circuits, microcontrollers, or any other type of circuit from any desired series or manufacturer to manage the flow of data into and out of the main memory 714, 716.

[0082] The programmable circuit platform 700 shown in the example also includes interface circuitry 720. Interface circuitry 720 can be implemented by hardware conforming to any type of interface standard, such as an Ethernet interface, a Universal Serial Bus (USB) interface, etc. Interfaces include Near Field Communication (NFC) interfaces, Peripheral Component Interconnect (PCI) interfaces, and / or Fast Peripheral Component Interconnect (PCIe) interfaces.

[0083] In the illustrated example, one or more input devices 722 are connected to interface circuitry 720. Input devices 722 allow users (e.g., human users, machine users, etc.) to input data and / or commands into programmable circuitry 712. Input devices 722 may be implemented using, for example, audio sensors, microphones, cameras (still or video), keyboards, buttons, mice, touchscreens, trackpads, trackballs, isotope devices, and / or voice recognition systems.

[0084] One or more output devices 724 are also connected to the interface circuitry 720 of the illustrated example. The output devices 724 may be implemented, for example, by display devices (e.g., light-emitting diode (LED), organic light-emitting diode (OLED), liquid crystal display (LCD), cathode ray tube (CRT) display, in-place switching (IPS) display, touchscreen, etc.), haptic output devices, printers, and / or speakers. Therefore, the interface circuitry 720 of the illustrated example typically includes a graphics driver card, a graphics driver chip, and / or graphics processor circuitry, such as a GPU.

[0085] The interface circuit 720 of the example shown also includes communication devices, such as a transmitter, receiver, transceiver, modem, residential gateway, wireless access point, and / or network interface, to facilitate the exchange of data with external machines (e.g., any type of computing device) via network 726. Communication can be achieved through, for example, Ethernet connections, digital subscriber line (DSL) connections, telephone line connections, coaxial cable systems, satellite systems, line-of-sight wireless systems, line-of-sight wireless systems, cellular telephone systems, optical connections, etc.

[0086] The programmable circuit platform 700 illustrated also includes one or more mass storage disks or devices 728 for storing firmware, software, and / or data. Examples of such mass storage disks or devices 728 include magnetic storage devices (e.g., floppy disks, drives, HDDs, etc.), optical storage devices (e.g., Blu-ray discs, CDs, DVDs, etc.), RAID systems, and / or solid-state storage disks or devices such as flash memory devices and / or SSDs.

[0087] Machine-readable instructions 732 can be generated by Figure 6 The instructions are implemented using machine-readable instructions and can be stored in a mass storage device 728, a volatile memory 714, a non-volatile memory 716 and / or at least one non-transient computer-readable storage medium, such as a removable CD or DVD.

[0088] This document discloses cryogenic fuel systems and related methods, including heat exchangers. The example cryogenic fuel systems disclosed herein include a heat exchanger that exchanges heat between a hydraulic fluid and cryogenic fuel used to fuel an aircraft. The examples disclosed herein reduce (e.g., decrease, eliminate, etc.) the need for radiators and / or other dedicated heat exchangers used to cool the hydraulic fluid for the aircraft and / or gas turbine engines. The examples disclosed herein enable a reduction in the size of the heat exchanger between the cryogenic fuel and the secondary heat source, which reduces the weight of the aircraft.

[0089] Further aspects are provided by the following topics:

[0090] An aircraft includes: a cryogenic fuel system comprising cryogenic fuel; a hydraulic system comprising hydraulic fluid; a gas turbine engine fluidly coupled to the cryogenic fuel system; and a heat exchanger fluidly coupled to the cryogenic fuel system for exchanging heat between the cryogenic fuel and at least one of (1) the hydraulic fluid or (2) a working fluid thermally coupled to the hydraulic system.

[0091] The aircraft according to any of the foregoing clauses further includes an aerodynamic surface, and wherein the hydraulic system controls the position of the aerodynamic surface.

[0092] In any of the preceding clauses of the aircraft, the gas turbine engine includes a control valve, and the hydraulic system controls the position of the control valve.

[0093] The aircraft according to any of the foregoing clauses, wherein the heat exchanger is a first heat exchanger, and further includes a second heat exchanger for transferring heat between the cryogenic fuel and the secondary heat source.

[0094] The aircraft according to any of the foregoing clauses, wherein the first heat exchanger is located upstream of the second heat exchanger.

[0095] The aircraft according to any of the foregoing clauses, wherein the heat exchanger is a first heat exchanger and further includes a thermal management system comprising: a heat transfer bus including a working fluid; a pump for pumping the working fluid; a second heat exchanger fluidly coupled to a secondary heat source; and a third heat exchanger fluidly coupled to the first heat exchanger, the second heat exchanger, and the pump.

[0096] For any of the preceding clauses, the cryogenic fuel is liquid hydrogen.

[0097] An apparatus comprising: a cryogenic fuel tank including fuel; a hydraulic system including hydraulic fluid; a burner fluidly connected to the cryogenic fuel tank; and a heat exchanger disposed between the burner and the cryogenic fuel tank for raising the temperature of the hydraulic fluid.

[0098] According to any of the foregoing clauses, the heat exchanger is configured to change the phase of the fuel from liquid to supercritical fluid.

[0099] The equipment according to any of the foregoing clauses, wherein the hydraulic system is a component of the aircraft's control system.

[0100] The equipment according to any of the foregoing clauses, wherein the hydraulic system is a component of the control system of a gas turbine engine including the burner.

[0101] The device according to any of the foregoing clauses, wherein the heat exchanger is a first heat exchanger, and further includes a second heat exchanger for transferring heat between the fuel and the secondary heat source.

[0102] According to any of the foregoing clauses, the first heat exchanger is located downstream of the second heat exchanger.

[0103] The device according to any of the foregoing clauses, wherein the heat exchanger is a first heat exchanger, and further comprises: a heat transfer bus including a working fluid; a second heat exchanger for transferring heat between the working fluid and a secondary heat source; and a third heat exchanger for exchanging heat between the working fluid and the hydraulic fluid, wherein the first heat exchanger is used to exchange heat between the working fluid and the fuel.

[0104] The device according to any of the foregoing clauses, wherein the heat exchanger is a first heat exchanger, the hydraulic system is a first hydraulic system, the hydraulic fluid is a first hydraulic fluid, and further comprises: a second hydraulic system including a second hydraulic fluid; and a second heat exchanger for transferring heat between the fuel and the second hydraulic fluid.

[0105] In any of the foregoing clauses, the fuel is cryogenic methane.

[0106] A non-transient computer-readable medium includes instructions that, when executed, cause a processor to: determine a heat transfer rate between a hydraulic fluid and cryogenic fuel in a first heat exchanger; determine a bypass ratio based on the heat transfer rate; and actuate a valve associated with a second heat exchanger based on the determined bypass ratio and the valve's position to control the volume of the cryogenic fuel flowing into the second heat exchanger.

[0107] According to any of the preceding clauses of the non-transient computer-readable medium, wherein the instructions, when executed, cause the processor to determine the heat transfer rate based on at least one of a first specific heat of the hydraulic fluid, a second specific heat of the cryogenic fuel, a first flow rate of the hydraulic fluid, a second flow rate of the cryogenic fuel, and a temperature difference between the cryogenic fuel and the hydraulic fluid.

[0108] According to any of the preceding clauses, a non-transient computer-readable medium wherein the instructions, when executed, cause the processor to determine the heat transfer rate based on the flight phase of the aircraft including the first heat exchanger.

[0109] According to any of the preceding clauses, a non-transient computer-readable medium wherein the instructions, when executed, cause the processor to determine the bypass ratio based on the liquid-vapor critical point of the cryogenic fuel.

[0110] The following claims are incorporated herein by reference. Although certain example systems, devices, articles of manufacture, and methods have been disclosed herein, the scope of this patent is not limited thereto. Rather, this patent covers all systems, devices, articles of manufacture, and methods that fall fully within the scope of the claims of this patent.

Claims

1. An aircraft, characterized in that, include: A cryogenic fuel system, wherein the cryogenic fuel system includes cryogenic fuel; A hydraulic system, comprising hydraulic fluid; A gas turbine engine, the gas turbine engine being fluidly connected to the cryogenic fuel system; and A heat exchanger fluidly connected to the cryogenic fuel system, the heat exchanger being used to exchange heat between the cryogenic fuel and at least one of (1) the hydraulic fluid or (2) the working fluid thermally connected to the hydraulic system.

2. The aircraft according to claim 1, characterized in that, It further includes a pneumatic surface, and wherein the hydraulic system controls the position of the pneumatic surface.

3. The aircraft according to claim 1, characterized in that, The gas turbine engine includes a control valve, and the hydraulic system controls the position of the control valve.

4. The aircraft according to claim 1, characterized in that, The heat exchanger is a first heat exchanger and further includes a second heat exchanger for transferring heat between the cryogenic fuel and the secondary heat source.

5. The aircraft according to claim 4, characterized in that, The first heat exchanger is located upstream of the second heat exchanger.

6. The aircraft according to claim 1, characterized in that, The heat exchanger is a first heat exchanger, and further includes a thermal management system comprising: A heat transfer bus, the heat transfer bus including a working fluid; Pump, the pump being used to pump the working fluid; A second heat exchanger, the second heat exchanger being fluidly connected to a secondary heat source; and A third heat exchanger is fluidly connected to the first heat exchanger, the second heat exchanger, and the pump.

7. The aircraft according to claim 1, characterized in that, The cryogenic fuel is liquid hydrogen.

8. A device, characterized in that, The device includes: A cryogenic fuel tank, the cryogenic fuel tank comprising fuel; A hydraulic system, comprising hydraulic fluid; A burner, the burner being fluidly connected to the cryogenic fuel tank; and A heat exchanger is disposed between the burner and the cryogenic fuel tank, and the heat exchanger is used to raise the temperature of the hydraulic fluid.

9. The device according to claim 8, characterized in that, The heat exchanger is configured to change the phase of the fuel from liquid to supercritical fluid.

10. The device according to claim 8, characterized in that, The hydraulic system mentioned above is a component of the aircraft's control system.

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