Method and apparatus for leak detection and mitigation of hydrogen fueled aircraft

Abstract

Systems, apparatus, articles, and methods for leak detection and mitigation of hydrogen-fueled aircraft are disclosed. An example apparatus disclosed herein includes machine-readable instructions and programmable circuitry to at least one of instantiate the machine-readable instructions or execute the machine-readable instructions to: determine a hydrogen concentration threshold for a location within a lower cowl of an engine of an aircraft based on engine conditions of the aircraft; determining a hydrogen concentration at the location based on an output of a hydrogen concentration sensor within the lower cover; comparing the hydrogen concentration to a hydrogen concentration threshold; and performing a mitigation action in the hydrogen fuel distribution system based on a comparison of the hydrogen concentration and the hydrogen concentration threshold.

Description

Technical Field

[0001] The present disclosure relates generally to hydrogen fuel dispensing systems and, more particularly, to methods and apparatus for leak detection and mitigation for hydrogen fueled aircraft. Background Art

[0002] The 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 the tank to the aircraft engines. In some examples, there may be multiple fuel tanks 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 with associated valves and / or piping to allow for feeding of the engines, refueling, defueling, isolation of individual tanks, and / or overall optimization of the aircraft center of gravity. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] A full and enabling disclosure of the preferred embodiments, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0004] Figure 1 is a simplified illustration of an aircraft including a hydrogen fuel distribution system in which the teachings of the present disclosure may be implemented.

[0005] Figure 2 yes Figure 1 Schematic diagram of a cross section of a gas turbine engine, showing the flow of hydrogen fuel therethrough.

[0006] Figure 3 yes Figure 1 and Figure 2 A side view of the lower cowling of a gas turbine engine showing the hydrogen concentration associated with an example leak.

[0007] Figure 4 is a block diagram of an example first leak detection system including an example fuel dispensing controller circuit implemented in accordance with the teachings of the present disclosure.

[0008] Figure 5 is a block diagram of an example second leak detection system including example fuel dispense controller circuitry implemented in accordance with the teachings of the present disclosure.

[0009] Figure 6 yes Figure 4 and Figure 5 A block diagram of the fuel distribution controller circuit.

[0010] Figure 7-10is a flowchart representing example machine-readable instructions and / or example operations that may be executed, instantiated, and / or performed by example programmable circuits to implement Figure 6 The fuel distribution controller circuit.

[0011] Fig.11 is a block diagram of an example processing platform including programmable circuitry configured to execute, instantiate and / or perform example machine-readable instructions and / or perform Figure 7-10 Example operations to implement Figure 6 The fuel distribution controller circuit. DETAILED DESCRIPTION

[0012] Pressurized gaseous hydrogen and liquid hydrogen are energy-dense fuel sources that can be used to power gas turbine engines. However, the small molecular size of hydrogen makes leaks in hydrogen fuel distribution systems more common than leaks in conventional fuel distribution systems. Examples disclosed herein include a leak detection system for a hydrogen fuel distribution system for a gas turbine engine that identifies and mitigates leaks in a lower hood of a gas turbine engine. Examples disclosed herein determine the hydrogen concentration at one or more locations within the lower hood and compare the determined hydrogen concentration to one or more thresholds associated with the location. In some examples disclosed herein, a comparison of the hydrogen concentration with the threshold value can be used to identify leaks associated with ignition and / or explosion risks. In some such examples disclosed herein, mitigation actions can be taken to reduce the ignition and / or explosion risks associated with the leak.

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

[0014] Pressurized and / or liquid hydrogen can be used as a fuel for a variety of applications, including gas turbine engines. Given the high pressure of stored hydrogen, the extremely low temperature of hydrogen, and the high flammability of hydrogen, leakage from the tank and / or other components of the hydrogen storage system (e.g., pumps, valves, heat exchangers, pipe joints, etc.) can be problematic. For example, hydrogen leakage can cause elevated hydrogen levels within portions of a gas turbine engine. Such high levels of hydrogen, if exposed to an ignition source, may ignite or explode (e.g., depending on the concentration of hydrogen and environmental conditions, etc.), which may be detrimental to the operation of the gas turbine engine. In addition, leakage can reduce the fuel efficiency of the gas turbine engine.

[0015] Examples disclosed herein include systems for detecting and mitigating leaks within a hydrogen fuel distribution system of a gas turbine engine. In some examples disclosed herein, leaks within a fuel distribution system can be detected by identifying a location of interest within a gas turbine engine (e.g., a potential leak location, a potential ignition source, etc.); determining a hydrogen concentration associated with a flammability risk and an explosion risk as a function of engine conditions; and estimating the hydrogen concentration at the location of interest based on the output of a hydrogen concentration sensor of the engine. In some examples disclosed herein, leaks within a fuel distribution system can be detected by determining a flammability threshold and / or an explosion threshold based on engine conditions at the location of a hydrogen concentration sensor and comparing the output of the hydrogen concentration sensor to a dynamically determined threshold. In some examples disclosed herein, if a leak and / or a fire is detected, mitigation actions can be taken, including operating a ventilation system of the gas turbine engine, opening one or more exhaust valves, disabling a fuel system, activating a fire extinguishing system, and the like.

[0016] Figure 1 1 is an example illustration of an aircraft 100 including an example fuel distribution system 102. The fuel distribution system 102 includes an example tank 104 of hydrogen that provides fuel to an example gas turbine engine 106. Figure 2 and Figure 3 An example implementation of a fuel distribution system 102 is described. An example tank 104 may contain hydrogen in various states, including liquid, gaseous, and cryogenically compressed states. An example tank 104 may be stored in any suitable location on an aircraft (e.g., in a wing, in a fuselage, in an external tank, etc.). In other examples, the tank 104 may include a plurality of tanks (referred to herein as a tank group, etc.).

[0017] although Figure 1 The illustrated aircraft 100 is an airplane, but the embodiments described herein may also be applied to other fixed-wing aircraft, including unmanned aerial vehicles (UAVs). The fuel distribution system 102 may be used to provide hydrogen fuel to be combusted in an example gas turbine engine 106 of the aircraft 100. Figure 1In the example shown, the aircraft includes a single gas turbine engine (eg, gas turbine engine 106 , etc.) In some examples, the aircraft 100 may include multiple gas turbine engines, such as multiple gas turbine engines mounted under the wings of the aircraft 100 .

[0018] exist Figure 1 In some examples, the fuel distribution system 102 is controlled and monitored by an example fuel distribution controller circuit 108. For example, the fuel distribution controller circuit 108 monitors the health of the fuel distribution system 102. For example, the fuel distribution controller circuit 108 can determine the outflow of hydrogen from the tank 104 and the inflow of hydrogen into the gas turbine engine 106. In some examples, the fuel distribution controller circuit 108 can determine that there is a leak and / or a fire in the fuel distribution system 102. In some such examples, when a leak or a fire is detected in the fuel distribution system 102, the fuel distribution controller circuit 108 can take mitigation actions to resolve the leak and / or the fire. Figure 4-6 An example implementation of the fuel distribution controller circuit 108 is described.

[0019] The embodiments of the fuel tank described herein may also be applicable to other applications where hydrogen is used as a fuel in the aircraft 100. The embodiments described herein may also be applied to engines other than gas turbine engines. Although the gas turbine engine 106 is a generator for the aircraft 100 that uses hydrogen as a fuel, hydrogen may also be used as a fuel for other generators. For example, the generator may be a fuel cell (e.g., a hydrogen fuel cell, etc.), where hydrogen is provided to the fuel cell to generate electricity by reacting with air.

[0020] Figure 2 Yes Figure 1 A portion of the fuel dispensing system 102 Figure 1 A schematic diagram of a cross section of a gas turbine engine 106. Figure 2 In the illustrated example, the gas turbine engine 106 includes an example fan frame 202, an example core frame 204, an example fork 206, an example engine core 210, and an example bypass 211. Figure 2 In the example shown, the area within the core frame 204 surrounding the engine core 210 is referred to as the lower cowling 212. Figure 2 In the example shown, the fuel distribution system 102 includes an example inlet line 214, an example fuel manifold 216, and an example plurality of inlets 218. Figure 2 In the example shown, the fuel distribution system 102 includes an example first hydrogen concentration sensor 220 , an example second hydrogen concentration sensor 222 , an example third hydrogen concentration sensor 224 , and an example fuel line sensor 226 .

[0021] exist Figure 2In the example shown, the fan frame 202 (e.g., fan nacelle, etc.) is an annular casing surrounding a fan (not shown), a bypass 211, and a core frame 204 of the gas turbine engine 106. It should be understood that the fan frame 202 may not be present in some configurations of the gas turbine engine 106. Figure 2 In the example shown, the fork 206 extends between the fan frame 202 and the core frame 204 in the bypass 211. The fork 206 is a structural component that supports the core frame 204 within the fan frame 202 and the bypass 211. Figure 2 In the example shown, the fork 206 is generally disposed at the 6 o'clock position. In other examples, the fork 206 may be disposed at any other suitable position. In some examples, the gas turbine engine 106 may include any suitable number of forks (e.g., two forks, three forks, etc.).

[0022] exist Figure 2 In the example shown, the core frame 204 (e.g., core nacelle, etc.) is a generally tubular casing that surrounds or at least partially forms an engine core 210. The engine core 210 includes turbomachinery other than a fan, and a combustor of the gas turbine engine 106. For example, the engine core 210 may include, in series flow order, a low pressure compressor (LPC) (not shown), a high pressure compressor (HPC) (not shown), a combustor (not shown), a high pressure turbine (HPT) (not shown), a low pressure turbine (LPT) (not shown), and an exhaust nozzle section (not shown). Figure 2 In the example shown, gas turbine engine 106 is a turbofan engine. It should be understood that the teachings of the present disclosure may also be applied to gas turbine engines having different configurations (eg, turbojets, turboprops, open rotors, turboshafts, etc.).

[0023] The fuel distribution system 102 supplies fuel from a hydrogen supply (e.g., tank 104, etc.) of the gas turbine engine 106 to the engine core 210. During operation, hydrogen flows through an inlet line 214 extending through the bifurcation 206, into a fuel manifold 216, which distributes the hydrogen between a plurality of inlets 218. Figure 2 In the example shown, a plurality of inlets 218 allow hydrogen fuel to enter the engine core 210. Figure 2In the example shown, multiple inlets 218 are distributed circumferentially around engine core 210. In other examples, multiple inlets 218 may have any other suitable distribution. Some or all of multiple inlets 218 may be implemented by fuel nozzles. In some examples, multiple inlets 218 may inject fuel into a combustor (not shown) of engine core 210. Additionally or alternatively, multiple inlets 218 may inject fuel into a compressor discharge nozzle (CDN) (e.g., an air spray nozzle, etc.) that mixes hydrogen fuel into compressed air from a compressor (not shown, etc.) of engine core 210. Figure 2 In the illustrated example, number of inlets 218 includes 18 inlets. In other examples, number of inlets 218 may include any other suitable number of inlets (eg, 1 inlet, 5 inlets, 20 inlets, 50 inlets, etc.).

[0024] Hydrogen concentration sensors 220, 222, 224, also referred to herein as gas sensors, are sensors that measure the concentration of hydrogen (e.g., hydrogen concentration, etc.) in adjacent air (e.g., air surrounding each sensor, etc.). In some examples, each of hydrogen concentration sensors 220, 222, 224 outputs an electrical parameter (e.g., voltage, current, etc.) corresponding to a specific concentration of hydrogen around a corresponding one of hydrogen concentration sensors 220, 222, 224. In some examples, hydrogen concentration sensors 220, 222, 224 may be implemented by one or more metal oxide semiconductor (MOS) sensors, one or more thermal conductivity sensors, one or more catalytic sensors, one or more electrochemical sensors, one or more other hydrogen sensors, and / or combinations thereof. Figure 2 In the illustrated example, fuel distribution system 102 includes three hydrogen concentration sensors (e.g., hydrogen concentration sensors 220, 222, 224, etc.). In other examples, fuel distribution system 102 may include any other suitable number of hydrogen concentration sensors (e.g., one sensor, two sensors, five sensors, ten sensors, etc.). In some examples, gas turbine engine 106 and / or other components of aircraft 100 may include hydrogen concentration sensors.

[0025] Fuel line sensor 226 measures parameters related to properties of the hydrogen flowing through inlet line 214. For example, fuel line sensor 226 may be a flow meter to measure the flow rate (e.g., mass flow rate, volume flow rate, etc.) of the hydrogen flowing through inlet line 214. Additionally or alternatively, fuel line sensor 226 may measure other parameters (e.g., temperature of the hydrogen, pressure of the hydrogen, etc.) that may be used to determine the flow rate of the hydrogen through inlet line 214. In some examples, fuel line sensor 226 may measure the pressure of the hydrogen flowing therethrough.

[0026] Figure 3 yes Figure 1 and Figure 2 3 is a side view of a lower shroud 212 of a gas turbine engine depicting a hydrogen concentration associated with an example leak 300, which results in the lower shroud 212 having an example hydrogen distribution 302. Figure 3 In the example shown, the lower housing 212 includes a plurality of locations of interest (LOIs), including a first LOI 304A, an example second LOI 304B, and an example third LOI 304C. Figure 3 In the example shown, the example fire detection system 306 monitors fires in the lower hood 212, the example fire suppression system 308 suppresses fires within the lower hood 212, and the example ventilation system 310 ventilates the lower hood 212. Figure 3 In the example shown, hydrogen distribution 302 is represented by dot shading. Generally, denser dot shading corresponds to a greater concentration of hydrogen within hydrogen distribution 302.

[0027] exist Figure 3 In the example shown, hydrogen distribution 302 corresponds to a steady state condition associated with leak 300. For example, due to the low molecular weight of hydrogen and the fuel distribution system 102 ( Figure 1 ), the hydrogen from leak 300 and / or the actual leak in fuel distribution system 102 quickly reaches a steady-state condition (e.g., in less than 10 seconds, etc.) where hydrogen distribution 302 is stable (e.g., no longer time-varying, etc.). In some examples, hydrogen distribution 302 caused by leak 300 may be based on gas turbine engine 106 ( Figure 1 ) and / or aircraft 100 ( Figure 1 ) conditions. For example, hydrogen distribution 302 may be based on one or more parameters (e.g., be affected by one or more parameters, etc.), including the mission phase of aircraft 100 (e.g., ground idle, cruise, takeoff, etc.), environmental conditions of aircraft 100 (e.g., altitude, temperature, air pressure, etc.), speed of gas turbine engine 106, pressure of fuel distribution system 102, flow rate of hydrogen through fuel distribution system 102. In some such examples, these parameters may cause hydrogen distribution 302 to change leak 300 (e.g., these parameters may cause hydrogen from a leak of the same size at the same location to diffuse differently within lower cowling 212, etc.). Figure 3In the illustrated example, the lower cowling 212 includes LOIs 304A, 304B, 304C. In some examples, the LOIs 304A, 304B, 304C are locations within the lower cowling 212 where hydrogen concentration is to be tracked. For example, the LOIs 304A, 304B, 304C may be located proximate to potential ignition sources (e.g., proximate to electrical components, proximate to a burner of the engine core 210, etc.), proximate to potential leak locations (e.g., proximate to a joint of a pipe, proximate to a valve, etc.), and / or proximate to a fire-susceptible component of the gas turbine engine 106. In some examples, the LOIs 304A, 304B, 304C are remote from (e.g., not proximate to, not close to, etc.) a hydrogen concentration sensor (e.g., Figure 2 Additionally or alternatively, the LOIs 304A, 304B, 304C may be located adjacent to one or more hydrogen concentration sensors of the fuel distribution system 102 (e.g., Figure 2 Although the lower cover 212 includes three LOIs 304A, 304B, 304C, it should be understood that the lower cover 212 may include any suitable number of LOIs (e.g., 1 LOI, 5 LOIs, 100 LOIs, etc.).

[0028] The fire detection system 306 monitors the lower cowling 212 to look for fires within the lower cowling 212 and / or the gas turbine engine 106. For example, the fire detection system 306 may output a signal indicating whether there is a current fire within the lower cowling 212. In some examples, the fire detection system 306 may include a multi-spectral infrared (MIR) detector. Additionally or alternatively, the fire detection system 306 may include one or more other thermal sensors, one or more radiation sensors, and / or one or more particle sensors.

[0029] When the fire detection system 306 detects a fire, the fire suppression system 308 suppresses the fire in the lower hood 212. For example, the fire suppression system 308 may include a water suppression system (e.g., a sprinkler, a water mist system, etc.), a carbon dioxide suppression system, and / or a fire extinguishing chemical agent (e.g., pentafluoroethane, perfluoro(2-methyl-3-pentanone), tetrafluoroethane, a noble gas, an inert gas, trifluoromethane, apaflurane, a halogenated alkane, a combination thereof, etc.). The ventilation system 310 ventilates the lower hood 212. For example, the ventilation system 310 may ventilate the lower hood 212 from a bypass (e.g., Figure 2In some examples, ventilation system 310 may include controllable elements (e.g., motor-driven fans, valves, openings with controllable sizes, etc.) that may be used to control the ventilation rate within lower hood 212. In some such examples, ventilation system 310 may be used to remove hydrogen from lower hood 212 (e.g., from leak 300, etc.).

[0030] Figure 4 is a block diagram of an example first leak detection system 400 implemented according to the teachings of the present disclosure. Figure 4 In the example shown, the leak detection system consists of Figure 1 The fuel distribution controller circuit 108 and the example memory 402. Figure 4 In the example shown, the fuel distribution controller circuit 108 accesses (e.g., receives, requests, etc.) example operating parameters 406, example hydrogen concentration sensor output 408, and example fire detector output 410. Figure 4 In the example shown, the memory 402 includes (e.g., stores, etc.) an example first relationship 412A, an example second relationship 412B, an example third relationship 414, and an example fourth relationship 416. Figure 4 In the illustrated example, operating parameters 406 (eg, engine condition parameters, etc.) include example mission phase parameters 418 , example aircraft parameters 420 , example engine parameters 422 , and example fuel system parameters 424 .

[0031] Memory 402 is computer memory associated with aircraft 100, gas turbine engine 106, and / or a user thereof. In some examples, memory 402 may be associated with a controller of gas turbine engine 106. In some examples, memory 402 may be provided by Fig.11 Local storage 1113, Fig.11 The volatile memory 1114, Fig.11 The non-volatile memory 1116 and / or Fig.11 The invention is implemented by the large-capacity storage device 1128.

[0032] The hydrogen concentration sensor output 408 is the output of a hydrogen concentration sensor (e.g., hydrogen concentration sensors 220, 222, 224, etc.) within the lower hood 212. In some examples, the hydrogen concentration sensor output 408 corresponds to the hydrogen concentration at a specific location (e.g., the location of the corresponding hydrogen concentration sensor, etc.) within the lower hood 212. In some examples, the hydrogen concentration sensor output 408 is a relative concentration of hydrogen (e.g., a percentage of hydrogen in the gas at the corresponding sensor, parts per million (ppm) of hydrogen at the corresponding sensor, etc.). The fire detector output 410 is the output of a fire detection system (e.g., the fire detection system 306, etc.). In some examples, the fire detector output 410 may be binary (e.g., a first output for no fire detected, a second output for a fire detected, etc.). In other examples, the fire detector output 410 may indicate a fire location within the lower hood 212 (e.g., a location of interest within the lower hood 212, etc.).

[0033] The first relationship 412A is a relationship between the lower explosion limit (LDL) of the H2 / air mixture as a function of temperature and pressure. That is, the first relationship 412A is related to the temperature and pressure of the H2 / air mixture by the minimum hydrogen concentration (e.g., H2 in air, etc.) that can be detonated. In some examples, the first relationship 412A can be determined empirically. In other examples, the first relationship 412A is determined analytically. In some examples, the first relationship 412A can be stored as a lookup table (e.g., a table similar to Table 1 below, etc.) and / or a graphical relationship. In other examples, the first relationship 412A can be stored as a mathematical function (e.g., LDL as a function of temperature and pressure, etc.). Typically, increasing ambient temperature reduces the LDL of hydrogen, while increasing ambient pressure increases the LDL of hydrogen.

[0034] The second relationship 412B is a relationship between the LFL of the H2 / air mixture as a function of temperature and pressure. That is, the second relationship 412B relates the minimum hydrogen concentration that can be ignited / burned (e.g., H2 in the air, etc.) to the temperature and pressure of the air. In some examples, the second relationship 412B can be determined empirically. In other examples, the second relationship 412B is determined analytically. In some examples, the second relationship 412B can be stored as a lookup table (e.g., Table 1, etc.) and / or a graphical relationship. In other examples, the second relationship 412B can be stored as a mathematical function (e.g., LFL as a function of temperature and pressure, etc.). Typically, increasing the ambient temperature reduces the LFL of hydrogen, while increasing the ambient pressure increases the LFL of hydrogen. Typically, at the same temperature and pressure, the LDL of the H2 / air mixture is greater than the LFL of the mixture.

[0035] An example lookup table that may be used to implement the second relationship 412B is described below:

[0036] Temperature (Fahrenheit) Pressure (psi) H2LFL (volume %) 0 5 5.9561 100 5 5.563 200 5 5.1699 300 5 4.7769 400 5 4.3838 500 5 3.9907 0 10 6.036 100 10 5.6429 200 10 5.2499 300 10 4.8568 400 10 4.4637 500 10 4.0706 0 15 6.1365 100 15 5.7435 200 15 5.3504 300 15 4.9573 400 15 4.5642 500 15 4.1712 0 20 6.1452 100 20 5.7521 200 20 5.359 300 20 4.966 400 20 4.5729 500 20 4.1798

[0037] Table 1: LFL as a function of pressure and temperature

[0038] In Table 1, the first column represents the temperature of the gas in degrees Fahrenheit, the second column represents the pressure of the gas in pounds per square inch (psi), and the third column represents the lower flammability limit (LFL) of hydrogen expressed as a volume percent. In such an example, if the temperature and pressure of the ambient temperature are known, Table 1 can be used to determine the LFL of hydrogen as a volume percent.

[0039] The third relationship 414 is the relationship between the operating parameter 406 and the under-hood condition. For example, the third relationship 414 can be Figure 2 and Figure 3 The third relationship 414 may relate the lower cowl condition (e.g., temperature, pressure, flow rate, etc.) of the lower cowl 212 to one or more operating parameters 406. For example, the third relationship 414 may relate the mission phase parameter 418 and / or the engine parameter 422 to the condition of the lower cowl 212. In some examples, the third relationship 414 may include a pressure map of the lower cowl 212 as a function of the mission phase parameter 418 and / or the engine parameter 422. In some examples, the third relationship 414 may include a flow rate map of the lower cowl 212 as a function of the mission phase parameter 418 and / or the engine parameter 422. In some examples, the third relationship 414 may include a thermal profile of the lower cowl 212 for each mission phase (e.g., a first thermal profile for cruise, a second thermal profile for takeoff, a third thermal profile for climb, etc.). In some examples, the third relationship 414 may be stored as a lookup table and / or a graphical relationship. In other examples, the third relationship 414 may be stored as a mathematical function (e.g., temperature and pressure profile of the lower cowl 212 as a function of one or more operating parameters 406, etc.). In some examples, the third relationship 414 may include a single temperature and / or pressure for each location of interest for each mission phase. An example lookup table is described below that may be used to implement the first relationship 412A for each mission at a single temperature and pressure:

[0040]

[0041] Table 2: Temperature and pressure at LOI during each mission phase

[0042] In Table 2, the first column indicates the task phase and the second column indicates the location of interest (e.g., Figure 3304C, etc.), the third column represents the temperature of the gas in degrees Fahrenheit, and the fourth column represents the pressure of the gas in pounds per square inch (psi). It should be understood that Table 2 may include additional mission phases (e.g., climb, descent, approach, etc.). Table 2 may be used to determine the expected conditions at each of the LOIs 304A, 304B, 304C during each mission phase. In such an example, if the temperature and pressure of the ambient temperature are known, Table 1 may be used to determine the LFL of hydrogen as a volume percent.

[0043] The fourth relationship 416 is between the hydrogen concentration sensor output 408 and the LOI within the lower cover 212 (eg, Figure 3 In some examples, the fourth relationship 416 may be a hydrogen distribution within the lower cover 212 generated based on the hydrogen concentration sensor output 408 (e.g., similar to Figure 3 302, etc.). Additionally or alternatively, the fourth relationship 416 can be a predicted hydrogen concentration at one or more LOIs (e.g., a first hydrogen concentration at the first LOI 304A based on the hydrogen concentration sensor output 408, a second hydrogen concentration at the second LOI 304B based on the hydrogen concentration sensor output 408, a third hydrogen concentration at the third LOI 304C based on the hydrogen concentration sensor output 408, etc.). In some examples, the fourth relationship 416 can be determined analytically (e.g., via computational fluid dynamics, etc.), empirically, and / or by simulating a leak via gas flow simulation software.

[0044] For example, if the hydrogen concentration sensors 220, 222, 224 output 0.95 H2 percent volume, 1 H2 percent volume, and 5 H2 percent volume, respectively, the fourth relationship 416 can be used to determine the hydrogen concentrations of 9.75 H2 percent volume, 7.5 H2 percent volume, and 6 H2 percent volume at the LOIs 304A, 304B, and 304C, respectively. For example, if the hydrogen concentration sensors 220, 222, 224 output 0.8 H2 percent volume, 0.85 H2 percent volume, and 15 H2 percent volume, respectively, the fourth relationship 416 can be used to determine the hydrogen concentrations of 4.125 H2 percent volume, 4.625 H2 percent volume, and 4 H2 percent volume at the LOIs 304A, 304B, and 304C, respectively. It should be understood that the fourth relationship 416 can vary based on the geometry and fluid flow path through the lower cover 212.

[0045] Mission phase parameter 418 is related to Figure 1The mission phase parameter 418 may be a parameter related to the current mission phase of the aircraft 100. For example, the mission phase parameter 418 may be a parameter indicating whether the aircraft is currently at ground idle, taking off, cruising, landing, etc. In some examples, the mission phase parameter 418 may be input by an operator of the aircraft 100. In other examples, the mission phase parameter 418 may be accessed from an autopilot system of the aircraft 100. The aircraft parameters 420 are related to the aircraft 100 and / or the current state of the aircraft 100. For example, the aircraft parameters 420 may include altitude, location (e.g., latitude, longitude, etc.), and / or model information related to the aircraft parameters 420. In some examples, the aircraft parameters 420 may be received from a position sensor of the aircraft 100 (e.g., a global positioning system (GPS) of the aircraft 100, an inertial navigation system (INS) of the aircraft 100, an altimeter of the aircraft 100, etc.). Additionally or alternatively, the aircraft parameters 420 may be input by a user of the aircraft 100.

[0046] Engine parameters 422 are parameters related to gas turbine engine 106. For example, engine parameters 422 may include an engine speed of gas turbine engine 106 and / or any other suitable parameters related to gas turbine engine 106 (e.g., a position of a variable airfoil of gas turbine engine 106, a temperature within gas turbine engine 106, a pressure within gas turbine engine 106, etc.). In some examples, engine parameters 422 may be accessed from one or more sensors associated with gas turbine engine 106. Additionally or alternatively, engine parameters 422 may be input by a user of aircraft 100. Fuel system parameters 424 are parameters related to fuel distribution system 102. For example, fuel system parameters 424 may include a pressure at one or more locations in fuel distribution system 102 and / or a flow rate of hydrogen entering gas turbine engine 106 through fuel distribution system 102. In some examples, engine parameters 422 may be accessed from one or more sensors associated with fuel distribution system 102 and / or gas turbine engine 106 (e.g., fuel line sensor 226, etc.).

[0047] exist Figure 4 In the example shown, the fuel distribution controller circuit 108 accesses the relationships 412A, 412B, 414, 416 stored in the memory 402, the operating parameters 406, the hydrogen concentration sensor output 408, and the fire detector output 410 to detect Figure 1 A leak in the fuel distribution system 102. Figure 4In the example shown, the fuel distribution controller circuit 108 generates an example predicted hydrogen concentration at box 426, an example predicted pressure and temperature at the LOI at box 428, a predicted LFL at the LOI at box 430, a predicted LDL at the LOI at box 432, and an example system recommendation at box 434. Figure 6 An example implementation of the fuel distribution controller circuit 108 is described in further detail below. Figure 7 and Figure 8 Description based on Figure 4 The leak detection system 400 implements the operation of the fuel distribution controller circuit 108 .

[0048] At block 426, the fuel distribution controller circuit 108 generates a predicted hydrogen concentration based on the hydrogen concentration sensor output 408 and the fourth relationship 416. For example, the fuel distribution controller circuit 108 may determine the predicted hydrogen concentration by inputting the hydrogen concentration sensor output 408 into the fourth relationship 416. In some such examples, the fuel distribution controller circuit 108 may determine (e.g., predict, etc.) the hydrogen concentration at each location of interest (e.g., the first LOI 304A, the second LOI 304B, the third LOI 304C, etc.) of the lower hood 212.

[0049] At block 428, the fuel distribution controller circuit 108 generates a predicted pressure and temperature at the LOI based on the operating parameters 406 and the third relationship 414. For example, the fuel distribution controller circuit 108 may determine the predicted pressure and temperature at the LOI by inputting the operating parameters (e.g., mission phase parameters 418, engine parameters 422, etc.) into the third relationship 414. In some such examples, the fuel distribution controller circuit 108 may determine (e.g., predict, etc.) the temperature, pressure, and / or flow rate of the air at each location of interest (e.g., first LOI 304A, second LOI 304B, third LOI 304C, etc.) of the lower cowling 212.

[0050] At block 430, the fuel distribution controller circuit 108 generates a predicted LFL at the LOI 4 based on the first relationship 412A and the predicted pressure and temperature at the LOI determined at 428. For example, the fuel distribution controller circuit 108 may determine the LFL at each location of interest by inputting the predicted temperature and pressure at the LOI determined at block 428 into the first relationship 412A. In some such examples, the fuel distribution controller circuit 108 may determine the hydrogen concentration associated with the LFL at each LOI (e.g., the first LOI 304A, the second LOI 304B, the third LOI 304C, etc.) of the lower cover 212. The fuel distribution controller circuit 108 generates a predicted LDL at the LOI based on the second relationship 412B and the predicted pressure and temperature at the LOI determined at block 428 at block 432. For example, the fuel distribution controller circuit 108 may determine the LDL at each location of interest by inputting the predicted temperature and pressure at the LOI determined at block 428 into the second relationship 412B. In some such examples, the fuel distribution controller circuit 108 may determine the hydrogen concentration associated with the LDL of each LOI of the lower hood 212 (eg, the first LOI 304A, the second LOI 304B, the third LOI 304C, etc.).

[0051] At block 434, the fuel distribution controller circuit 108 generates a system recommendation based on the predicted LFL at the LOI determined at block 430, the predicted LDL at the LOI, the predicted hydrogen concentration determined at block 426, and the fire detector output 410. For example, the fuel distribution controller circuit 108 may compare the predicted LFL at the LOI determined at block 430 with the predicted hydrogen concentration determined at block 426 to determine if the LFL and / or LDL are at any LOI within the lower hood 212. An example table describing this comparison is shown below:

[0052]

[0053]

[0054] Table 3: Comparison of predicted hydrogen concentrations during takeoff for hydrogen LFL at locations of interest

[0055] In Table 3, the first column represents the location of interest (e.g., LOI 304A, 304B, 304C, etc.), the second column represents the LFL of hydrogen expressed as a volume percentage (e.g., the predicted LFL at the LOI determined at block 430, etc.), the third column represents the predicted hydrogen concentration determined at 426 for each of the LOIs, and the fourth column represents the ratio of the third column to the second column, the safety ratio. In some examples, when the fuel distribution controller circuit 108 determines that the safety ratio at the LOI is greater than 1 (e.g., the predicted hydrogen concentration is greater than the H2 LFL at the LOI), the fuel distribution controller circuit 108 may determine that there is a fire risk in the lower hood. It should be understood that similar comparisons may be made to determine whether the hydrogen concentration exceeds the H2 LDL at each LOI.

[0056] The fuel distribution controller circuit 108 may generate a system recommendation including an indication (e.g., a command, an advisory, a warning, etc.) to activate a fire suppression system of the gas turbine engine 106 and / or disable the fuel distribution system 102 when the fire detector output 410 includes an indication that a fire is present in the lower cowling 212. In some examples, the fuel distribution controller circuit 108 may generate a system recommendation including an indication to disable the fuel distribution system 102 and / or release a frangible panel system of the lower cowling 212 when the hydrogen concentration at the location of interest exceeds the LDL at the location of interest. In some examples, the fuel distribution controller circuit 108 may generate a system recommendation including an indication to increase the ventilation rate within the lower cowling 212, reduce the pressure of the fuel in the fuel distribution system 102, and / or disable the fuel distribution system 102 when the hydrogen concentration at the location of interest exceeds the LFL at the location of interest. The following is in conjunction with Fig.10 Example operations for generating system recommendations are described.

[0057] Figure 5 is a block diagram of another example leak detection system 500 implemented according to the teachings of the present disclosure. The second leak detection system 500 includes Figure 4 The example memory 502 and the fuel distribution controller circuit 108. Figure 5 In the example shown, the fuel distribution controller circuit 108 receives Figure 4 The operating parameters 406 (e.g., Figure 4 Mission phase parameters 418, Figure 4 Aircraft parameters 420, Figure 4 The engine parameters 422 and Figure 4 Fuel system parameters 424, etc.), Figure 4 The hydrogen concentration sensor output 408 and Figure 4 The fire detector output 410. Figure 5 An example memory 502 is similar to Figure 44. Example memory 402 of FIG. 4, except that memory 502 includes multiple security thresholds 503 and does not include the relationships stored in memory 402.

[0058] A plurality of safety thresholds 503 are stored in the memory 502. The plurality of safety thresholds 503 correspond to LFL and / or LDL hydrogen concentrations at the location of each hydrogen concentration sensor (e.g., hydrogen concentration sensors 220, 222, 224, etc.) in the lower cowling 212 under one or more engine conditions. For example, the plurality of safety thresholds 503 may include thresholds for each hydrogen concentration sensor in each mission phase (e.g., a first safety threshold for the first hydrogen concentration sensor 220 during cruising, a second safety threshold for the first hydrogen concentration sensor 220 during takeoff, a third safety threshold for the second hydrogen concentration sensor 222 during ground idle, a fourth safety threshold for the second hydrogen concentration sensor 222 during takeoff, etc.). Additionally or alternatively, the plurality of safety thresholds 503 may include thresholds for each hydrogen concentration sensor for other engine conditions (e.g., engine speed, altitude, etc.). In some examples, the plurality of safety thresholds 503 may be determined empirically, analytically, and / or via simulation. In some such examples, the plurality of safety thresholds 503 may be based on LDL and / or LFL, etc., at expected temperatures and / or pressures at the locations of the hydrogen concentration sensors 220, 222, 224 during corresponding engine conditions. In some examples, a safety margin may be applied to some or all of the plurality of safety thresholds 503 (e.g., a safety margin between 1.5 and 3, etc.). An example table describing example values ​​for the plurality of safety thresholds 503 is given below:

[0059]

[0060] Table 4: Comparison of predicted hydrogen concentrations with hydrogen LFL at ground idle at sensor location

[0061] In Table 4, the first column represents the location of the sensors (e.g., hydrogen concentration sensors 220, 222, 224, etc.) within the lower cowling 212, the second column represents the hydrogen concentration threshold determined for each sensor location at ground idle during the threshold identification at box 504, the third column represents the hydrogen concentration threshold determined for each sensor location at takeoff during the threshold identification at box 504, and the fourth column represents the hydrogen concentration threshold determined for each sensor location at cruise during the threshold identification at box 504. It should be understood that similar thresholds for LDL at each of the sensor locations can be determined.

[0062] exist Figure 5 In the example shown, the fuel distribution controller circuit 108 accesses a plurality of safety thresholds 503 stored in the memory 502, operating parameters 406, and hydrogen concentration sensor outputs 408 and fire detector outputs 410 to detect Figure 1 A leak in the fuel distribution system 102. Figure 5 In the example shown, the fuel distribution controller circuit 108 performs a threshold identification at block 504 and compares the hydrogen concentration to the identified threshold at block 506. After comparing the hydrogen concentration to the identified threshold at block 506, the fuel distribution controller circuit 108 outputs an example system recommendation at block 508. Figure 7 and Fig. 9 Description based on Figure 5 The leak detection system 500 implements the operation of the fuel distribution controller circuit 108 .

[0063] At block 504, during threshold identification, the fuel distribution controller circuit 108 determines a threshold to compare the hydrogen concentration sensor output 408 based on the operating parameters 406. For example, if multiple safety thresholds 503 are generated based on the mission phase, the fuel distribution controller circuit 108 may identify which of the multiple safety thresholds 503 to use based on the mission phase parameter 418. In other examples, based on how the multiple safety thresholds 503 are generated, the fuel distribution controller circuit 108 may determine which of the multiple safety thresholds 503 to use based on other operating parameters in the operating parameters 406. In some examples, if the mission phase is unknown, the fuel distribution controller circuit 108 may select the lowest safety threshold of the multiple safety thresholds 503 for each sensor position.

[0064] At box 506, during the comparison of the hydrogen concentration to the identified threshold, the fuel distribution controller circuit 108 compares the hydrogen concentration sensor output 408 to the corresponding safety threshold 503 in the plurality of safety thresholds 503 identified during the threshold identification at box 504. In some examples, the fuel distribution controller circuit 108 may determine when the output of any hydrogen concentration exceeds the corresponding safety threshold in the plurality of identified safety thresholds 503 (e.g., when the output of the first hydrogen concentration sensor 220 exceeds the corresponding LFL safety threshold, when the output of the first hydrogen concentration sensor 220 exceeds the corresponding LDL safety threshold, etc.). An example table describing an example of this comparison is shown below:

[0065]

[0066] Table 5: Comparison of predicted hydrogen concentrations with hydrogen LFL at ground idle at sensor location

[0067] In Table 5, the first column represents the location of the sensor (e.g., hydrogen concentration sensor 220, 222, 224, etc.) within the lower cover 212, the second column represents the hydrogen concentration threshold value determined for each sensor location during the threshold identification at box 504, the third column represents the hydrogen concentration sensor output 408 at the sensor location, and the fourth column represents the ratio of the third column to the second column, the safety ratio. In some examples, when the fuel distribution controller circuit 108 determines that the safety ratio at the sensor is greater than 1 (e.g., the measured hydrogen concentration is greater than the threshold value at the location), the fuel distribution controller circuit 108 can determine that there is a fire risk in the lower cover. It should be understood that a similar comparison can be made to determine whether the hydrogen concentration causes an explosion risk at the sensor location.

[0068] At block 508, the fuel distribution controller circuit 108 generates a system recommendation based on the comparison of the hydrogen concentration to the identified threshold value determined at block 506 and the fire detector output 410. For example, the fuel distribution controller circuit 108 may generate a system recommendation including an indication (e.g., a command, an advisory, a warning, etc.) to activate a fire suppression system of the gas turbine engine 106 and / or disable the fuel distribution system 102 when the fire detector output 410 includes an indication that a fire is present in the lower cowling 212. In some examples, the fuel distribution controller circuit 108 may generate a system recommendation including an indication to disable the fuel distribution system 102 and / or release a frangible panel system of the lower cowling 212 when the output of one of the hydrogen concentration sensors exceeds one of the plurality of safety thresholds 503 corresponding to the LDL at the location of the hydrogen concentration sensor. In some examples, the fuel distribution controller circuit 108 may generate a system recommendation that includes an indication to increase the ventilation rate within the lower hood 212, reduce the pressure of the fuel in the fuel distribution system 102, and / or disable the fuel distribution system 102 when the output of one of the hydrogen concentration sensors exceeds one of the plurality of safety thresholds 503 corresponding to the LFL at the location of the hydrogen concentration sensor. Fig.10 Describes example operations for generating system recommendations.

[0069] Figure 6 It is used to detect and mitigate leaks and / or fires in hydrogen fuel distribution systems. Figure 4 and Figure 5 A block diagram of an example implementation of the fuel distribution controller circuit 108 is shown in FIG. Figure 6In the example shown, the fuel distribution controller circuit 108 includes an example sensor interface circuit 602, an example memory interface circuit 604, an example fire detector circuit 606, an example threshold determiner circuit 608, an example underhood condition predictor circuit 610, an example hydrogen concentration predictor circuit 612, an example threshold comparator circuit 614, an example leak and fire mitigation circuit 616, and an example system interface circuit 618. Example implementations of the fuel distribution controller circuit 108 may be used with Figure 4 The leak detection system 400 and / or Figure 5 Used in conjunction with the leak detection system 500.

[0070] Figure 6 The fuel distribution controller circuit 108 may be instantiated (e.g., created for any length of time, generated for any length of time, implemented, performed, etc.) by a programmable circuit such as a central processing unit (CPU) executing a first instruction. Additionally or alternatively, Figure 6 The fuel distribution controller circuit 108 may be instantiated (e.g., instantiated for any length of time, generated for any length of time, implemented, performed, etc.) by (i) an application specific integrated circuit (ASIC) and / or (ii) a field programmable gate array (FPGA), which is constructed and / or configured to perform operations corresponding to the first instruction in response to the execution of the second instruction. It should be understood that Figure 2 Some or all of the circuits may therefore be instantiated at the same or different times. Figure 2 Some or all of the circuits of may be instantiated, for example, in one or more threads that execute concurrently on hardware and / or serially on hardware. Furthermore, in some examples, Figure 1 and / or Figure 4-6 Some or all of the circuits may be implemented by microprocessor circuits executing instructions and / or FPGA circuits performing operations for implementing one or more virtual machines and / or containers.

[0071] The sensor interface circuit 602 is Figure 1 The sensor interface circuit 602 may access sensor data from sensors of the aircraft 100, the fuel distribution system 102, and / or the gas turbine engine 106. For example, the sensor interface circuit 602 may access sensor outputs from the hydrogen concentration sensors 220, 222, 224 (e.g., Figure 4 and Figure 5 hydrogen concentration sensor output 408, etc.) and / or the sensor output of the fire detection system 306 (e.g., Figure 4 and Figure 5In some examples, sensor interface circuit 602 may access (e.g., retrieve, query, receive, etc.) outputs of other sensors from aircraft 100, fuel distribution system 102, and / or gas turbine engine 106. In some such examples, Figure 4 and Figure 5 Some or all of the operating parameters 406 of can be determined based on the sensor output accessed by the sensor interface circuit 602. In some examples, the sensor interface circuit 602 can convert the received sensor data from a machine-readable format to a human-readable format (e.g., a string, a floating point number, an integer, etc.). In some examples, the sensor interface circuit 602 is instantiated by a programmable circuit that executes sensor interface circuit instructions and / or is configured to perform operations such as those performed by Figure 7-10 The operations represented by the flowchart.

[0072] In some examples, the fuel distribution controller circuit 108 includes means for interfacing with a sensor. For example, the means for interfacing with a sensor may be implemented by a sensor interface circuit 602. In some examples, the sensor interface circuit 602 may be implemented by, for example, Fig.11 The sensor interface circuit 602 may be instantiated by a programmable circuit of the example programmable circuit 1112 of the example programmable circuit 1112. Additionally or alternatively, the sensor interface circuit 602 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the sensor interface circuit 602 may be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.) that are configured and / or constructed to execute some or all of the machine-readable instructions and / or to execute some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are also suitable.

[0073] The memory interface circuit 604 interfaces with a memory associated with the aircraft 100, the fuel distribution system 102, and / or the gas turbine engine 106. For example, the memory interface circuit 604 may be from Figure 4 412A, 412B, 414, 416 of the memory 402. For example, the memory interface circuit 604 may be from Figure 5 503. In some examples, the memory interface circuit 604 may be configured to Figure 4The memory interface circuit 604 may be configured to create a flag (e.g., a warning, an indication, a data structure, etc.) in the memory 402 and / or the memory 502 of the present invention, which indicates that there is a leak in the fuel distribution system 102 and / or in the lower cover 212. In some examples, the memory interface circuit 604 may be instantiated by a programmable circuit that executes memory interface circuit instructions and / or may be configured to execute, for example, Figure 7-10 The operations represented by the flowchart.

[0074] In some examples, the fuel distribution controller circuit 108 includes means for interfacing with a memory. For example, the means for determining may be implemented by the memory interface circuit 604. In some examples, the memory interface circuit 604 may be implemented by a memory interface circuit such as Fig.11 The memory interface circuit 604 may be instantiated by a programmable circuit of the example programmable circuit 1112 of the example programmable circuit 1112. Additionally or alternatively, the memory interface circuit 604 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the memory interface circuit 604 may be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.) that are configured and / or constructed to execute some or all of the machine-readable instructions and / or to execute some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are also suitable.

[0075] The fire detector circuit 606 determines whether a fire is detected in the lower hood 212 and / or the fuel distribution system 102. For example, the fire detector circuit 606 can interface with the fire detection system 306 to determine whether a fire is present in the lower hood 212 and / or the fuel distribution system 102. In some examples, the fire detector circuit 606 can determine whether a fire is present in the system based on the fire detector output 410. In some examples, the fire detector circuit 606 can determine the location of the fire within the lower hood 212 (e.g., at one of the hydrogen concentration sensors 220, 222, 224, at one of the LOIs 304A, 304B, 304C, etc.). In some examples, the fire detector circuit 606 is instantiated by a programmable circuit that executes fire detector instructions and / or is configured to execute commands such as those executed by Figure 7-10 The operations represented by the flowchart.

[0076] In some examples, the fuel distribution controller circuit 108 includes means for detecting a fire. For example, the means for determining may be implemented by the fire detector circuit 606. In some examples, the fire detector circuit 606 may be implemented by, for example, Fig.11The fire detector circuit 606 may be instantiated by a programmable circuit of the example programmable circuit 1112 of the example programmable circuit 1112. Additionally or alternatively, the fire detector circuit 606 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the fire detector circuit 606 may be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.) that are configured and / or constructed to execute some or all of the machine-readable instructions and / or to execute some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are also suitable.

[0077] The threshold determiner circuit 608 determines the hydrogen concentration threshold of the lower cover 212. For example, the threshold determiner circuit 608 may determine the threshold of the lower cover 212 based on the LFL and / or LDL of hydrogen and / or the current condition of the lower cover 212 (e.g., the current temperature distribution of the lower cover 212, the current pressure of the lower cover 212, etc.). In some examples, for Figure 4 The leak detection system 400 of the present invention can be configured to detect the leakage of the LOI in the lower cover 212 based on the temperature and / or pressure at each LOI and the threshold value determiner circuit 608. Figure 4 In some such examples, if the relationships 412A, 412B are lookup tables, the threshold determiner circuit 608 can determine the LDL and LFL for each location of interest by inputting the temperature and / or pressure at the location of interest into the lookup table. In some examples, for Figure 5 In the leak detection system 500 of the embodiment of the present invention, the threshold determiner circuit 608 can determine the threshold value of each position of the hydrogen concentration sensors 220, 222, 224 based on the operating parameters 406. In some such examples, for each mission phase, each sensor position can have an associated threshold value for LDL and an associated threshold value for LFL. Additionally or alternatively, the threshold determiner circuit 608 can determine the threshold value for each position (e.g., each sensor position and / or each position of interest, etc.) based on any other operating parameter in the operating parameters 406. In some examples, the threshold determiner circuit 608 is instantiated by a programmable circuit that executes a threshold determiner instruction and / or is configured to execute instructions such as by Figure 7-10 The operations represented by the flowchart.

[0078] In some examples, the fuel distribution controller circuit 108 includes means for determining the threshold. For example, the means for determining the threshold may be implemented by the threshold determiner circuit 608. In some examples, the threshold determiner circuit 608 may be implemented by, for example, Fig.11The threshold determiner circuit 608 may be instantiated by a programmable circuit of the example programmable circuit 1112 of . Additionally or alternatively, the threshold determiner circuit 608 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the threshold determiner circuit 608 may be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.) that are configured and / or constructed to execute some or all of the machine-readable instructions and / or to execute some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are also suitable.

[0079] The lower cowl condition predictor circuit 610 determines a condition of the lower cowl 212. For example, the lower cowl condition predictor circuit 610 may determine a temperature, pressure, and / or flow rate within the lower cowl 212 of the gas turbine engine 106. For example, the lower cowl condition predictor circuit 610 may determine a condition of the lower cowl 212 based on one or more operating parameters 406. In some examples, the lower cowl condition predictor circuit 610 may determine a condition of the lower cowl based on mission phase parameters 418 (e.g., a first temperature, a first pressure, and a first flow rate for cruise, a second temperature, a second pressure, and a second flow rate for takeoff, etc.).

[0080] Additionally or alternatively, the lower cowl condition predictor circuit 610 may determine the condition within the lower cowl based on other operating parameters in the operating parameters 406 (e.g., engine speed, throttle position, environmental conditions of the aircraft 100, etc.). In some examples, the lower cowl condition predictor circuit 610 may determine the condition within the lower cowl based on other operating parameters in the operating parameters 406 (e.g., engine speed, throttle position, environmental conditions of the aircraft 100, etc.). Figure 4 The third relationship 414 of the lower cowl 212 determines the condition of the lower cowl 212. In other examples, the lower cowl condition predictor circuit 610 can determine the condition of the lower cowl 212 analytically (eg, mathematically, via flow principles, etc.) and / or via modeling.

[0081] In some examples, the lower hood condition predictor circuit 610 can determine the temperature, pressure, and / or flow rate at discrete locations within the lower hood 212 (e.g., the locations of the LOIs 304A, 304B, 304C, the hydrogen concentration sensors 220, 222, 224, etc.). Additionally or alternatively, the lower hood condition predictor circuit 610 can generate a temperature map of the lower hood 212, a pressure map of the lower hood 212, and / or a flow rate map within the lower hood 212. In some examples, the lower hood condition predictor circuit 610 is instantiated by a programmable circuit that executes lower hood condition predictor instructions and / or is configured to execute, such as by Figure 7-10 The flowchart represents those operations.

[0082] In some examples, the fuel distribution controller circuit 108 includes means for determining a condition of the lower cowl and / or means for determining a condition of the gas turbine engine. For example, the means for determining may be implemented by the lower cowl condition predictor circuit 610. In some examples, the lower cowl condition predictor circuit 610 may be implemented by, for example, Fig.11 The programmable circuit of the example programmable circuit 1112 of the example programmable circuit 1112 is instantiated. Additionally or alternatively, the under-hood condition predictor circuit 610 can be instantiated by any other combination of hardware, software, and / or firmware. For example, the under-hood condition predictor circuit 610 can be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.) that are configured and / or constructed to execute some or all of the machine-readable instructions and / or to execute some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are also suitable.

[0083] The hydrogen concentration predictor circuit 612 determines the hydrogen concentration within the lower hood 212. For example, the hydrogen concentration predictor circuit 612 may determine the hydrogen concentration within the lower hood 212 based on the hydrogen concentration sensor output 408 (e.g., based on the output of one or more hydrogen concentration sensors 220, 222, 224, etc.). In some examples, the hydrogen concentration predictor circuit 612 may determine the hydrogen concentration within the lower hood 212 based on the fourth relationship 416. Additionally or alternatively, the hydrogen concentration predictor circuit 612 may determine the hydrogen concentration within the lower hood 212 analytically (e.g., via mathematics, flow principles, etc.) and / or via modeling. In some examples, the hydrogen concentration predictor circuit 612 may determine the hydrogen concentration rate at discrete locations (e.g., LOI 304A, 304B, 304C, etc.) within the lower hood 212. Additionally or alternatively, the lower hood condition predictor circuit 610 may generate a hydrogen concentration map of the lower hood 212 (e.g., similar to Figure 3 In some examples, the underhood condition predictor circuit 610 may use the generated hydrogen concentration to identify the location of a leak within the underhood. Figure 3 If the hydrogen distribution 302 is generated by the hydrogen concentration predictor circuit 612, the hydrogen concentration predictor circuit 612 can identify the location of the leak 300 as the first LOI 304A. In some examples, the hydrogen concentration predictor circuit 612 is instantiated by a programmable circuit that executes hydrogen concentration predictor instructions and / or is configured to perform operations such as by Figure 7-10 The operations represented by the flowchart.

[0084] In some examples, the fuel distribution controller circuit 108 includes means for determining the hydrogen concentration. For example, the means for determining may be implemented by the hydrogen concentration predictor circuit 612. In some examples, the hydrogen concentration predictor circuit 612 may be implemented by a device such as Fig.11 The example programmable circuit 1112 of the example programmable circuit 1112 is instantiated. Additionally or alternatively, the hydrogen concentration predictor circuit 612 can be instantiated by any other combination of hardware, software, and / or firmware. For example, the hydrogen concentration predictor circuit 612 can be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.) that are configured and / or constructed to execute some or all of the machine-readable instructions and / or to execute some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are also suitable.

[0085] The threshold comparator circuit 614 compares the hydrogen concentration at one or more locations within the lower cover 212 (e.g., the location of one or more hydrogen concentration sensors 220, 222, 224, one or more LOIs 304A, 304B, 304C, etc.) to a threshold value determined by the threshold determiner circuit 608. The threshold comparator circuit 614 determines when the hydrogen concentration at one or more locations within the lower cover 212 exceeds the LFL and / or LDL associated with the location. In some examples, the threshold comparator circuit 614 may compare the predicted hydrogen concentration at the location of interest (e.g., one of the LOIs 304A, 304B, 304C, etc.) to the LDL and / or LFL determined by the threshold determiner circuit 608 for the location of interest. For example, the threshold comparator circuit 614 may determine when one of the hydrogen concentration sensor outputs 408 associated with a corresponding one of the hydrogen concentration sensors exceeds the LFL threshold or LDL threshold associated with the hydrogen concentration sensor. For example, the threshold comparator circuit 614 may compare the output of the selected hydrogen concentration sensor to an applicable safety threshold (e.g., Figure 5 In some examples, the threshold comparator circuit 614 is instantiated by a programmable circuit that executes a threshold comparator instruction and / or is configured to execute instructions such as by Figure 7-10 The operations represented by the flowchart.

[0086] In some examples, the fuel distribution controller circuit includes means for comparing the hydrogen concentration to a threshold value. For example, the means for determining may be implemented by a threshold comparator circuit 614. In some examples, the threshold comparator circuit 614 may be implemented by, for example, Fig.11In some embodiments, the threshold comparator circuit 614 may be instantiated by a programmable circuit of the example programmable circuit 1112 ...

[0087] The leak and fire mitigation circuit 616 determines one or more mitigation actions based on the detected leak, detected fire, detected explosion risk, and / or detected fire risk within the lower cowling 212. For example, the leak and fire mitigation circuit 616 may determine (e.g., generate a command, generate an instruction, set a flag, etc.) to activate a Figure 3 The fire extinguishing system 308 changes the pressure of the hydrogen fuel in the fuel distribution system 102, changes Figure 3 The leakage and fire mitigation circuit 616 can determine which mitigation actions to take based on the output of the threshold comparator circuit 614. In some such examples, the leakage and fire mitigation circuit 616 can access a memory (e.g., Figure 4 Memory 402, Figure 5 502, etc.) to determine when a flag indicating the presence of a detected fire risk and / or a detected explosion risk within the lower cover 212 is set. In some examples, the leak and fire mitigation circuit 616 is instantiated by a programmable circuit that executes leak and fire mitigation instructions and / or is configured to execute instructions such as by Figure 7-10 The operations represented by the flowchart.

[0088] In some examples, the fuel distribution controller circuit 108 includes means for mitigating a detected fire and / or a detected leak. For example, the means for mitigating a detected fire and / or a detected leak may be implemented by a leak and fire mitigation circuit 616. In some examples, the leak and fire mitigation circuit 616 may be implemented by, for example, Fig.11The leakage and fire mitigation circuit 616 may be instantiated by a programmable circuit of the example programmable circuit 1112 of the example programmable circuit 1112. Additionally or alternatively, the leakage and fire mitigation circuit 616 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the leakage and fire mitigation circuit 616 may be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.) that are configured and / or constructed to execute some or all of the machine-readable instructions and / or to perform some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are also suitable.

[0089] The system interface circuit 618 interfaces with the fuel distribution system 102, the fire suppression system 308, the ventilation system 310, and / or other systems of the aircraft and / or the gas turbine engine 106. For example, the system interface circuit 618 may respond to a command from the leak and fire mitigation circuit 616 to activate Figure 3 The fire extinguishing system 308 changes the pressure of the hydrogen fuel in the fuel distribution system 102, changes Figure 3 The ventilation rate of the ventilation system 310 and / or release of the fragile panel of the core frame 204. In some examples, the system interface circuit 618 is instantiated by a programmable circuit that executes system interface instructions and / or is configured to perform such as by Figure 7-10 The operations represented by the flowchart.

[0090] In some examples, the fuel distribution controller circuit includes a device for a system for a gas turbine engine. For example, the device for a system for a gas turbine engine can be implemented by the system interface circuit 618. In some examples, the system interface circuit 618 can be implemented by a system such as Fig.11 The system interface circuit 618 may be instantiated by a programmable circuit of the example programmable circuit 1112 of the example programmable circuit 1112. Additionally or alternatively, the system interface circuit 618 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the system interface circuit 618 may be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.) that are configured and / or constructed to execute some or all of the machine-readable instructions and / or to execute some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are also suitable.

[0091] Although in Figure 6 The implementation is shown in Figure 1 An example of a fuel distribution controller circuit, but Figure 6One or more of the elements, processes and / or devices shown in the example may be combined, separated, rearranged, omitted, eliminated and / or implemented in any other manner. In addition, the example sensor interface circuit 602, the example memory interface circuit 604, the example fire detector circuit 606, the example threshold determiner circuit 608, the example under-hood condition predictor circuit 610, the example hydrogen concentration predictor circuit 612, the example threshold comparator circuit 614, the example leak and fire mitigation circuit 616, the example system interface circuit 618, and / or more generally, Figure 6 The example fuel distribution controller circuit 108 may be implemented by hardware alone, or by hardware in combination with software and / or firmware. Thus, for example, the example sensor interface circuit 602, the example memory interface circuit 604, the example fire detector circuit 606, the example threshold determiner circuit 608, the example under-hood condition predictor circuit 610, the example hydrogen concentration predictor circuit 612, the example threshold comparator circuit 614, the example leak and fire mitigation circuit 616, the example system interface circuit 618, and / or more generally, the example fuel distribution controller circuit 108 may be implemented by programmable circuitry in combination with machine-readable instructions (e.g., firmware or software), processor circuitry, analog circuitry, digital circuitry, logic circuitry, a programmable processor, a programmable microcontroller, a graphics processing unit (GPU), a digital signal processor (DSP), an ASIC, a programmable logic device (PLD), and / or a field programmable logic device (FPLD) (e.g., an FPGA). In addition, Figure 6 An example fuel distribution controller circuit 108 may include Figure 6 One or more elements, processes and / or devices other than or in place of the one or more elements, processes and / or devices shown Figure 6 One or more of the one or more elements, processes and / or devices shown, and / or may include more than one of any or all of the elements, processes and devices shown.

[0092] Figure 7-10 It shows that the representation can be executed by a programmable circuit to implement and / or instantiate Figure 6 The example machine readable instructions and / or representations of the fuel distribution controller circuit 108 may be executed by a programmable circuit to implement and / or instantiate Figure 6 The machine readable instructions may be a flowchart of an example operation of the fuel distribution controller circuit 108. The machine readable instructions may be for use by a programmable circuit (e.g., in conjunction with the following Fig.11The machine-readable instructions may be one or more executable programs or a portion of one or more executable programs executed by the programmable circuit 1112 shown in the example programmable circuit platform 1100 discussed above and / or may be one or more functions or a portion of one or more functions to be performed by the example programmable circuit (e.g., FPGA). In some examples, the machine-readable instructions cause an operation, task, etc. to be performed and / or executed in an automated manner in the real world. As used herein, "automatically" means without human intervention.

[0093] 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 disks (e.g., Blu-ray disks, compact disks (CDs), digital versatile disks (DVDs), etc.), redundant arrays of independent disks (RAIDs), registers, ROMs, solid-state drives (SSDs), SSD memories, non-volatile memories (e.g., electrically erasable programmable read-only memories (EEPROMs), flash memory, etc.), volatile memories (e.g., any type of random access memory (RAM), etc.), and / or any other storage devices or storage disks. The instructions of the non-transitory computer-readable and / or machine-readable media may be programmed and / or executed by programmable circuits 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 circuits. The machine-readable instructions may be distributed across multiple hardware devices and / or executed by two or more hardware devices (e.g., a server and a client hardware device). For example, a client hardware device may be implemented by an endpoint client hardware device (e.g., a hardware device associated with a human and / or machine user) or an intermediate client hardware device gateway (e.g., a radio access network (RAN)) that may facilitate communications between a server and an endpoint client hardware device. Similarly, a non-transitory computer-readable storage medium may include one or more media. Furthermore, although reference is made to Figure 7-10The flowchart shown describes an example program, but many other methods of implementing the example fuel distribution controller circuit 108 may be used instead. For example, the execution order of the blocks of the flowchart may be changed, and / or some of the blocks described may be changed, eliminated, or combined. Additionally or alternatively, any or all of the blocks of the flowchart may 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.), which are configured to perform corresponding operations without executing software or firmware. The programmable circuits may be distributed in 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, the programmable circuit may be a CPU and / or an FPGA located in the same package (e.g., the same integrated circuit (IC) package or located in two or more separate housings), one or more processors in a single machine, multiple processors distributed on multiple servers in a server rack, multiple processors distributed on one or more server racks, etc., and / or any combination thereof.

[0094] The machine-readable instructions described herein may be stored in one or more of a compressed format, an encrypted format, a segmented format, a compiled format, an executable format, a packaged format, etc. The 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.), a bit stream (e.g., a computer-readable bit stream, a machine-readable bit stream, etc.), etc.) or a data structure (e.g., as part of an instruction, code, a representation of code, etc.) that can be used to create, manufacture, and / or generate machine-executable instructions. For example, the machine-readable instructions may be segmented and stored on one or more storage devices, disks, and / or computing devices (e.g., servers) located in the same or different locations of a network or a collection of networks (e.g., in the cloud, in an edge device, etc.). The machine-readable instructions may need to be installed, modified, adapted, updated, combined, supplemented, configured, decrypted, decompressed, unpacked, distributed, reassigned, compiled, etc., so that they can be directly read, interpreted, and / or executed by a computing device and / or other machine. For example, machine-readable instructions may be stored in multiple portions that are separately compressed, encrypted, and / or stored on separate computing devices, where the portions, when decrypted, decompressed, and / or combined, form a set of computer-executable and / or machine-executable instructions that implement one or more functions and / or operations that together may form a program such as described herein.

[0095] In another example, the machine-readable instructions may be stored in a state that can be read by a programmable circuit, but require the addition of a library (e.g., a dynamic link library (DLL)), a software development kit (SDK), an application programming interface (API), etc., in order to execute the machine-readable instructions on a particular computing device or other device. In another example, the machine-readable instructions and / or corresponding programs may need to be configured (e.g., stored settings, data inputs, 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 the specific format or state of the machine-readable instructions and / or programs.

[0096] The machine-readable instructions described herein may be represented by any past, present or future instruction language, scripting language, programming language, etc. For example, the machine-readable instructions may 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.

[0097] As mentioned above, Figure 7-10The example operations of can be implemented using executable instructions (e.g., computer-readable and / or machine-readable instructions) stored on one or more non-transitory computer-readable and / or machine-readable media. As used herein, the terms non-transitory computer-readable medium, non-transitory computer-readable storage medium, non-transitory machine-readable medium, and / or non-transitory machine-readable storage medium are explicitly defined to include any type of computer-readable storage device and / or storage disk, and exclude propagation signals and exclude transmission media. Examples of such non-transitory computer-readable medium, non-transitory computer-readable storage medium, non-transitory machine-readable medium, and / or non-transitory 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 in any duration (e.g., for an extended period of time, permanently, for a brief instance, for a temporary buffer, and / or for a cache of information). As used herein, the terms "non-transitory computer-readable storage device" and "non-transitory machine-readable storage device" are defined to include any physical (mechanical, magnetic and / or electrical) hardware to retain information for a period of time, but exclude propagating signals and exclude transmission media. Examples of non-transitory computer-readable storage devices and / or non-transitory machine-readable storage devices include any type of random access memory, any type of read-only memory, solid-state memory, flash memory, optical disks, magnetic disks, disk drives, and / or redundant arrays of independent 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 by computer-readable instructions, machine-readable instructions, etc., and / or is manufactured to execute computer-readable instructions, machine-readable instructions, etc.

[0098] "Include" and "comprising" (and all forms and states thereof) are used herein as open-ended terms. Thus, whenever a claim adopts any form of "include" or "comprising" (e.g., includes, contains, has, etc.) as a preamble or within any kind of claim narrative, it should be understood that additional elements, terms, etc. may be present without exceeding the scope of the corresponding claim or narrative. As used herein, when the phrase "at least" is used as a transitional term, such as in the preamble of a claim, it is open-ended in the same manner as the terms "include" and "comprising" are open-ended. The term "and / or" when used, for example, in a form such as A, B, and / or C, refers to any combination or subset of A, B, C, such as (1) A alone, (2) B alone, (3) C alone, (4) A and B, (5) A and C, (6) B and C, or (7) A and B and C. As used herein in the context of describing structures, components, items, objects, and / or things, the phrase "at least one of A and B" is intended to mean embodiments that include any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects, and / or things, the phrase "at least one of A or B" is intended to mean embodiments that include any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. As used herein in the context of describing the performance or execution of a process, instruction, action, activity, etc., the phrase "at least one of A and B" is intended to mean embodiments that include any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B. Similarly, as used herein in the context of describing the performance or execution of a process, instruction, action, activity, etc., the phrase "at least one of A or B" is intended to mean embodiments that include any of (1) at least one A, (2) at least one B, or (3) at least one A and at least one B.

[0099] As used herein, singular references (e.g., "a," "an," "first," "second," etc.) do not exclude a plurality. As used herein, the term "a" or "an" object refers to one or more of the object. The terms "a" (or "an"), "one or more," and "at least one" are used interchangeably herein. In addition, although listed separately, multiple devices, elements, or actions may be implemented by, for example, the same entity or object. In addition, although individual features may be included in different examples or claims, these features may possibly be combined, and inclusion in different examples or claims does not mean that a combination of features is not feasible and / or disadvantageous.

[0100] Generally, the same reference numbers will be used throughout the drawings and accompanying written description to refer to the same or like parts.The drawings are not necessarily drawn to scale.

[0101] As used herein, unless otherwise specified, the term "above" describes the relationship of two parts relative to the earth. A first part is above a second part if the second part has at least one part between the earth and the first part. Likewise, as used herein, a first part is "below" a second part when the first part is closer to the earth than the second part. As described above, the first part can be above or below the second part, have one or more of the following: have other parts between them, have no other parts between them, the first part and the second part are in contact, or the first part and the second part are in direct contact with each other.

[0102] As used in this patent, stating that any part (e.g., a layer, film, region, area, or plate) is in any way on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part indicates that the referenced part is in contact with the other part, or that the referenced part is above the other part with one or more intermediate parts located therebetween.

[0103] As used herein, unless otherwise specified, connection references (e.g., attached, coupled, connected, and joined) may include intermediate members between elements to which the connection reference refers and / or relative movement between those elements. As such, connection references do not necessarily infer that two elements are directly connected and / or in fixed relation to one another. As used herein, stating that any component is "in contact with" another component is defined to mean that there are no intermediate components between the two components.

[0104] Unless otherwise specifically stated, descriptors such as "first," "second," "third," etc., are used herein without in any way implying or otherwise indicating any meaning of priority, physical order, arrangement in a list, and / or ordering, but are merely used as labels and / or arbitrary names to distinguish elements for ease of understanding of the disclosed examples. In some examples, the descriptor "first" may be used to refer to an element in the detailed description, while the same element may be referred to in the claims using different descriptors (e.g., "second" or "third"). In such cases, it should be understood that such descriptors are only used to clearly identify those elements within the context of the discussion (e.g., within the claims) where the elements may, for example, otherwise share the same name.

[0105] As used herein, the phrase "in communication," includes variations thereof, including direct communication and / or indirect communication through one or more intermediate host components, and does not require direct physical (e.g., wired) communication and / or constant communication, but instead includes selective communication at periodic intervals, predetermined intervals, non-periodic intervals, and / or one-time events.

[0106] As used herein, "programmable circuitry" is defined to include (i) one or more special-purpose electronic circuits (e.g., application-specific circuits (ASICs)) that are constructed to perform specific operations and include one or more semiconductor-based logic devices (e.g., electrical hardware implemented by one or more transistors), and / or (ii) one or more general-purpose semiconductor-based electronic circuits that can be programmed using instructions to perform specific functions and / or operations and include one or more semiconductor-based logic devices (e.g., electrical hardware implemented by one or more transistors). Examples of programmable circuitry include a programmable microprocessor (e.g., a central processing unit (CPU)) that can execute a first instruction to perform one or more operations and / or functions, a field programmable gate array (FPGA) that can be programmed using a second instruction so that the configuration and / or structuring of the FPGA instantiates one or more operations and / or functions corresponding to the first instruction, a graphics processor unit (GPU) that can execute a first instruction to perform one or more operations and / or functions, a digital signal processor (DSP) that can execute a first instruction to perform one or more operations and / or functions, an XPU, a network processing unit (NPU), one or more microcontrollers that can execute a first instruction to perform one or more operations and / or functions, and / or an integrated circuit such as an application-specific integrated circuit (ASIC). For example, an XPU may be implemented by a heterogeneous computing system including multiple types of programmable circuits (e.g., one or more FPGAs, one or more CPUs, one or more GPUs, one or more NPUs, one or more DSPs, etc., and / or any combination thereof) and orchestration technology (e.g., an application programming interface (API)) that may distribute computing tasks to any of the multiple types of programmable circuits that are suitable and available to perform the computing tasks.

[0107] As used herein, an integrated circuit / circuit is defined as one or more semiconductor packages containing one or more circuit elements (e.g., transistors, capacitors, inductors, resistors, current paths, diodes, etc.). For example, an integrated circuit may be implemented as one or more of an ASIC, an FPGA, a chip, a microchip, a programmable circuit, a semiconductor substrate coupling multiple circuit elements, a system on a chip (SoC), etc.

[0108] Figure 7 is to indicate that a programmable circuit can be executed, instantiated, and / or performed to identify Figure 1and Figure 2 A flow chart of example machine readable instructions and / or example operations 700 for leaks and / or fires in the fuel distribution system 102 is provided. Figure 7 The example machine readable instructions and / or example operations 700 begin at block 702 where the sensor interface circuit 602 accesses the fire detector output 410. For example, the sensor interface circuit 602 may access the fire detector output 410 from Figure 3 The fire detector output 410 of the fire detection system 306 of the sensor interface circuit 602 is shown in FIG. 704. In some examples, the fire detector output 410 may be a binary output (e.g., “0” for no fire detected in the lower hood 212, “1” for a fire detected in the lower hood 212, etc.). In other examples, the fire detector output 410 may identify the location of the fire within the lower hood 212 (e.g., at a particular LOI of the lower hood 212, etc.). In some examples, the sensor interface circuit 602 may convert the fire detector output 410 from a machine-readable format to a human-readable format. At block 704, the fire detector circuit 606 determines when a fire is detected in the lower hood 212 and / or the fuel distribution system 102. For example, the fire detector circuit 606 may determine when a fire is present in the system based on the fire detector output 410. If the fire detector circuit 606 determines that a fire is present in the lower hood 212 and / or the fuel distribution system 102, the operation 700 proceeds to block 714. If the fire detector circuit 606 determines that a fire is not present in the lower hood 212 and / or the fuel distribution system 102 , the operations 700 proceed to block 706 .

[0109] At block 706, the sensor interface circuit 602 and / or the memory interface circuit 604 accesses Figure 4 and Figure 5 406 (e.g., mission phase parameters 418, aircraft parameters 420, engine parameters 422, fuel system parameters 424, etc.). For example, sensor interface circuitry 602 may access some or all of the operating parameters from one or more sensors associated with aircraft 100 and / or gas turbine engine 106. In some examples, sensor interface circuitry 602 may access some or all of the operating parameters 406 from a user interface associated with aircraft 100 (e.g., input from a pilot of aircraft 100, etc.). In other examples, memory interface circuitry 604 may access some or all of the operating parameters 406 from a memory associated with fuel distribution system 102 (e.g., Figure 4 Memory 402, Figure 5 At block 708, the sensor interface circuit 602 retrieves the hydrogen concentration sensor output 408. For example, the sensor interface circuit 602 may access Figure 2The output of one or more hydrogen concentration sensors 220, 222, 224. In some examples, the sensor interface circuit 602 can convert the hydrogen concentration sensor output 408 from a machine-readable format to a human-readable format.

[0110] At block 710, the fuel distribution controller circuit 108 performs a leak detection operation. For example, the fuel distribution controller circuit 108 may communicate with Figure 4 The leak detection system 400 and / or methods associated with Figure 5 The following is a method associated with the leakage detection system 500 to perform leakage detection operations. Figure 8 Description Figure 4 Example operation of the leak detection system 400 to detect a leak. Fig. 9 Description Figure 5 Example operation of the leak detection system 500 to detect a leak.

[0111] At box 712, the leak and fire mitigation circuit 616 determines whether a leak that causes a fire risk and / or an explosion risk is detected in the fuel distribution system 102. For example, the leak and fire mitigation circuit 616 can determine when a leak exists in the fuel distribution system 102 based on the output of the fuel distribution controller circuit 108 during the execution of box 710 (e.g., via a flag and / or indicator in a memory, etc.). If the leak and fire mitigation circuit 616 determines that there is a leak in the fuel distribution system 102 that causes a fire risk and / or an explosion risk, the operation 700 proceeds to box 714. If the leak and fire mitigation circuit 616 determines that there is no leak in the fuel distribution system 102 that causes a fire risk and / or an explosion risk, the operation 700 ends. At box 714, the leak and fire mitigation circuit 616 and the system interface circuit 618 perform mitigation operations. The following is combined with Fig.10 Describe an example mitigation operation.

[0112] Figure 8 is a flowchart representing example machine-readable instructions and / or example operations 800 that may be executed, instantiated, and / or performed by a programmable circuit to perform an operation via Figure 4 The leak detection system 400 and / or Figure 7 Operation 800 begins at block 802, where the memory interface circuit 604 accesses parameter relationships from the memory 402. For example, the memory interface circuit 604 may access (e.g., read, retrieve, request, etc.) one or more relationships 412A, 412B, 414, 416 from the memory 402. At block 804, the under-mask condition predictor circuit 610 selects a location of interest within the under-mask 212. For example, the under-mask condition predictor circuit 610 may select Figure 3 The lower cowl condition predictor circuit 610 may select one of the LOIs 304A, 304B, 304C of the lower cowl 212 of the embodiment of the present invention. In some examples, the lower cowl condition predictor circuit 610 may sequentially select the LOIs 304A, 304B, 304C. Additionally or alternatively, the lower cowl condition predictor circuit 610 may select one of the previously unselected locations of interest. In some examples, the lower cowl condition predictor circuit 610 may select one of the previously unselected LOIs 304A, 304B, 304C that has a substantial risk of ignition and / or explosion.

[0113] At block 806, the lower cowl condition predictor circuit 610 predicts the temperature and pressure at the selected location of interest based on the operating parameters 406 and the third relationship 414 (e.g., a relationship between the operating parameters and the lower cowl condition, etc.). For example, the lower cowl condition predictor circuit 610 may predict the temperature and pressure at the selected location of interest during execution of block 804 based on the mission phase parameters 418, the aircraft parameters 420, and / or the engine parameters 422. For example, if the third relationship 414 is a lookup table, the lower cowl condition predictor circuit 610 may input the operating parameters to determine the temperature and pressure at the selected location of interest. In other examples, the lower cowl condition predictor circuit 610 may use the operating parameters to generate a temperature map and / or a pressure map of the lower cowl 212.

[0114] At block 808, the threshold determiner circuit 608 determines the LDL and LFL at the selected location of interest based on the temperature and pressure at the selected location of interest. For example, the threshold determiner circuit 608 may determine the LDL at the selected location of interest based on the first relationship 412A (e.g., a relationship between LDL and temperature / pressure, etc.) and the determined temperature and pressure. Additionally or alternatively, the threshold determiner circuit 608 may determine the LFL at the selected location of interest based on the second relationship (e.g., a relationship between LFL and temperature / pressure, etc.) and the determined temperature and pressure.

[0115] At block 810, the hydrogen concentration predictor circuit 612 predicts the hydrogen concentration at the selected location of interest based on the hydrogen concentration sensor output 408. For example, the hydrogen concentration predictor circuit 612 may determine the hydrogen concentration at the selected location of interest based on the hydrogen concentration sensor output 408 and a fourth relationship 416 (e.g., a relationship between the hydrogen concentration sensor output 408 and the hydrogen concentration at the location of interest, etc.). In other examples, the hydrogen concentration predictor circuit 612 may use the hydrogen concentration sensor output 408 to generate a hydrogen concentration map (e.g., via flow modeling, analysis, etc.).

[0116] At block 812, the threshold comparator circuit 614 determines whether the predicted hydrogen concentration at the selected location of interest exceeds the LDL. For example, the threshold comparator circuit 614 may compare the predicted hydrogen concentration at the location of interest determined during execution of block 810 with the predicted LDL at the selected location of interest determined during execution of block 808. In some examples, the threshold comparator circuit 614 may determine a ratio of the predicted hydrogen concentration to the LDL to determine a safe ratio. In some such examples, if the threshold comparator circuit 614 determines that the safe ratio is greater than 1, the threshold comparator circuit 614 may determine that the LDL has been exceeded at the location. If the threshold comparator circuit 614 determines that the predicted hydrogen concentration exceeds the predicted LDL, operation 800 proceeds to block 814. If the threshold comparator circuit 614 determines that the predicted hydrogen concentration does not exceed the predicted LDL, operation 800 proceeds to block 816.

[0117] At block 814, the memory interface circuit 604 may set a flag that a leak has been detected and that the hydrogen concentration at the location of interest exceeds the LDL at the selected location of interest. For example, the memory interface circuit 604 may set a flag (e.g., an indication, warning, notification, data structure, etc.) in the memory 402 that the LDL has been exceeded. In some examples, because the LDL of hydrogen is greater than the LFL of hydrogen under all flow conditions, the memory interface circuit 604 may set a flag that the LFL at the location of interest has also been exceeded.

[0118] At block 816, the threshold comparator circuit 614 determines whether the predicted hydrogen concentration at the selected location of interest exceeds the LFL. For example, the threshold comparator circuit 614 may compare the predicted hydrogen concentration at the location of interest determined during execution of block 810 with the predicted LFL at the selected location of interest determined during execution of block 808. In some examples, the threshold comparator circuit 614 may determine a ratio of the predicted hydrogen concentration to the LFL to determine a safety ratio. In some such examples, if the threshold comparator circuit 614 determines that the safety ratio is greater than 1, the threshold comparator circuit 614 may determine that the LFL has been exceeded at the location. If the threshold comparator circuit 614 determines that the predicted hydrogen concentration exceeds the predicted LFL, the operation 800 proceeds to block 818. If the threshold comparator circuit 614 determines that the predicted hydrogen concentration does not exceed the predicted LFL, the operation 800 proceeds to block 820.

[0119] At block 818, the memory interface circuit 604 may set a flag that a leak has been detected and the hydrogen concentration at the location of interest exceeds the LFL at the selected location of interest. For example, the memory interface circuit 604 may set a flag (e.g., an indication, warning, notification, data structure, etc.) in the memory 402 that the LFL has been exceeded.

[0120] At block 820, the undercoat condition predictor circuit 610 determines whether to select another location of interest. For example, if there is an unselected LOI 304A, 304B, 304C among the LOIs 304A, 304B, 304C that has not been analyzed via execution of blocks 804, 806, 808, 810, 812, 814, 816, 818, the undercoat condition predictor circuit 610 may determine another location of interest to select. Additionally or alternatively, the undercoat condition predictor circuit 610 may determine to select another location of interest based on continued operation of the gas turbine engine 106 (e.g., the leak detection system 400 may continuously check for leaks through a mission, etc.). If the undercoat condition predictor circuit 610 determines to select another location of interest, the operation 800 returns to block 804. If the undercoat condition predictor circuit 610 determines not to select another location of interest, the operation 800 ends and / or returns to Figure 7 Operation 700.

[0121] Fig. 9 is a flowchart representing example machine-readable instructions and / or example operations 900 that may be executed, instantiated, and / or performed by a programmable circuit to perform an operation via Figure 5 The leak detection system 500 and / or Figure 7 Operation 900 begins at block 902, where the memory interface circuit 604 accesses LDL and LFL thresholds from the memory 502. For example, the memory interface circuit 604 may access (e.g., read, retrieve, request, etc.) Figure 5 502 of the memory 502. At block 904, the threshold determiner circuit 608 determines the applicable safety threshold in the safety threshold 503 based on the operating parameters 406. For example, if the safety threshold 503 is divided based on the mission phase (e.g., a first threshold for each of the hydrogen concentration sensors 220, 222, 224 when the aircraft takes off, a second threshold for each of the hydrogen concentration sensors 220, 222, 224 when the aircraft is cruising, etc.), the threshold determiner circuit 608 may determine the applicable threshold based on the mission phase parameter 418. Additionally or alternatively, if the safety threshold 503 is based on other parameters (e.g., aircraft parameters in the aircraft parameters 420, engine parameters in the engine parameters 422, fuel system parameters in the fuel system parameters 424, etc.), the threshold determiner circuit 608 may determine the applicable safety threshold in the safety threshold 503 based on the corresponding operating parameters in the operating parameters 406.

[0122] At block 906, the underhood condition predictor circuit 610 selects a hydrogen concentration sensor associated with the fuel distribution system 102 and / or within the underhood 212. For example, the underhood condition predictor circuit 610 may select Figure 2 In some examples, the under-hood condition predictor circuit 610 may sequentially select the hydrogen concentration sensors 220, 222, 224. Additionally or alternatively, the under-hood condition predictor circuit 610 may select one of the hydrogen concentration sensors 220, 222, 224 that was not previously selected.

[0123] At box 908, the threshold comparator circuit 614 determines whether one of the hydrogen concentration sensor outputs 408 associated with the selected hydrogen concentration sensor exceeds the LDL threshold. For example, the threshold comparator circuit 614 may compare the output of the selected hydrogen concentration sensor with an applicable safety threshold (e.g., one of the safety thresholds 503 of the selected hydrogen concentration sensor for LDL, etc.). In some examples, the threshold comparator circuit 614 may determine the ratio of the measured hydrogen concentration to the threshold associated with LDL to determine the safety ratio. In some such examples, if the threshold comparator circuit 614 determines that the safety ratio is greater than 1, the threshold comparator circuit 614 may determine that the LDL threshold has been exceeded at the location. If the threshold comparator circuit 614 determines that one of the hydrogen concentration sensor outputs 408 associated with the selected hydrogen concentration sensor exceeds the LDL threshold, the operation 900 proceeds to box 910. If the threshold comparator circuit 614 determines that one of the hydrogen concentration sensor outputs 408 associated with the selected hydrogen concentration sensor does not exceed the LDL threshold, the operation 900 proceeds to box 912.

[0124] At block 910, the memory interface circuit 604 may set a flag that a leak has been detected and the hydrogen concentration at the selected hydrogen concentration sensor exceeds the LDL at the selected location of interest. For example, the memory interface circuit 604 may set a flag (e.g., an indication, warning, notification, data structure, etc.) in the memory 502 that the LDL has been exceeded at the selected hydrogen concentration sensor.

[0125] At block 912, the threshold comparator circuit 614 determines whether one of the hydrogen concentration sensor outputs 408 associated with the selected hydrogen concentration sensor exceeds the LFL threshold. For example, the threshold comparator circuit 614 may compare the output of the selected hydrogen concentration sensor with an applicable safety threshold (e.g., one of the safety thresholds 503 of the selected hydrogen concentration sensor for LFL, etc.). In some examples, the threshold comparator circuit 614 may determine a ratio of the measured hydrogen concentration to the threshold associated with the LFL to determine a safety ratio. In some such examples, if the threshold comparator circuit 614 determines that the safety ratio is greater than 1, the threshold comparator circuit 614 may determine that the LFL threshold has been exceeded at the location. If the threshold comparator circuit 614 determines that one of the hydrogen concentration sensor outputs 408 associated with the selected hydrogen concentration sensor exceeds the LFL threshold, the operation 900 proceeds to block 914. If the threshold comparator circuit 614 determines that one of the hydrogen concentration sensor outputs 408 associated with the selected hydrogen concentration sensor does not exceed the LFL threshold, the operation 900 proceeds to block 916. At block 914, the memory interface circuit 604 may set a flag that a leak has been detected and the hydrogen concentration at the selected hydrogen concentration sensor exceeds the LFL at the selected location of interest. For example, the memory interface circuit 604 may set a flag (e.g., an indication, warning, notification, data structure, etc.) in the memory 502 that the LFL has been exceeded at the selected hydrogen concentration sensor.

[0126] At box 916, the sensor interface circuit 602 determines whether to select another location of interest. For example, the sensor interface circuit 602 may determine to select another location of interest when there is an unselected hydrogen concentration sensor 220, 222, 224 of the hydrogen concentration sensors 220, 222, 224 that has not been analyzed via execution of boxes 906, 908, 910, 912, 914. Additionally or alternatively, the sensor interface circuit 602 may determine to select another hydrogen concentration sensor of the hydrogen concentration sensors 220, 222, 224 based on continued operation of the gas turbine engine 106 (e.g., the leak detection system 500 may continuously check for leaks through a mission, etc.). If the sensor interface circuit 602 determines to select another location of interest, the operation 900 returns to box 906. If the underhood condition predictor circuit 610 determines not to select another location of interest, the operation 900 ends and / or returns to Figure 7 Operation 700.

[0127] Fig.10 is a flowchart representing example machine readable instructions and / or example operations 1000 that may be executed, instantiated, and / or performed by programmable circuitry to mitigate a problem caused by Figure 4The leak detection system 400 and Figure 5 The leak detection system 500 of the embodiment of the present invention may be configured to detect a fire and / or leak in the lower housing 212. Operation 1000 may begin at block 1002, where the fire detector circuit 606 and / or the leak and fire mitigation circuit 616 may determine when a fire is present in the lower housing 212. For example, the fire detector circuit 606 may be configured to detect a fire based on the fire detector output 410 (e.g., Figure 3 Additionally or alternatively, the leak and fire mitigation circuit 616 may access (e.g., read, etc.) a memory associated with the aircraft 100, the fuel distribution system 102, and / or the gas turbine engine 106 (e.g., Figure 4 Memory 402, Figure 5 502, etc.) to determine when the leak detection system of the aircraft 100 was previously passed (e.g., Figure 4 Leak detection system 400, Figure 5 The leak detection system 500, etc.) detects a fire (e.g., during execution of Figure 7 during frame 704).

[0128] At block 1004, system interface circuit 618 disables the supply of hydrogen to fuel distribution system 102. For example, system interface circuit 618 may close valves within fuel distribution system 102 and / or tank 104 to prevent hydrogen fuel from flowing into gas turbine engine 106. Additionally or alternatively, system interface circuit 618 may stop operating a pump of fuel distribution system 102 and / or tank 104 to stop fuel from flowing through fuel distribution system 102 and / or tank 104. In some examples, disabling the supply of hydrogen by system interface circuit 618 prevents further hydrogen from supplying fuel to a fire within lower hood 212.

[0129] At block 1006, the system interface circuit 618 may determine to activate Figure 3 For example, the system interface circuit 618 can cause the fire extinguishing system 308 to release water mist, carbon dioxide and / or fire extinguishing chemical agents into the lower cover 212.

[0130] At block 1008, the fire detector circuit 606 determines whether a fire is still detected within the lower cover 212. For example, the fire detector circuit 606 may determine whether a fire is still detected within the lower cover 212. Figure 71000 determines whether a fire still exists in the lower hood 212 in a manner consistent with the execution of block 704 and / or block 1002 of the present invention. If the fire detector circuit 606 determines that a fire still exists in the lower hood 212, the operation 1000 returns to block 1006 (e.g., continuing operation of the fire suppression system 308, etc.). If the fire detector circuit 606 determines that a fire still does not exist in the lower hood 212 (e.g., the fire has been suppressed, etc.), the operation 1000 proceeds to block 1010. At block 1010, the system interface circuit 618 re-enables the hydrogen supply. For example, the system interface circuit 618 may reverse the changes to the fuel distribution system 102 and / or the tank 104 to return the hydrogen fuel flow to the gas turbine engine 106. In some examples, when a severe leak is detected within the lower hood 212 (e.g., a leak that results in a H2 concentration above the LFL and / or LDL, etc.), the execution of block 1010 may be omitted.

[0131] At block 1012, the leak and fire mitigation circuit 616 determines whether an explosion risk has been detected. For example, the leak and fire mitigation circuit 616 may access (e.g., read, etc.) Figure 4 Memory 402 and / or Figure 5 memory 502 to determine when a flag indicating a location within the lower cover 212 is exceeded (e.g., during execution of Figure 8 The flag set during block 814 of Fig. 9 Additionally or alternatively, the leak and fire mitigation circuit 616 may cause the fuel distribution controller circuit 108 to perform operation 800 and / or operation 900 to determine when there is a risk of explosion within the lower hood 212. In some such examples, the leak and fire mitigation circuit 616 may remove the flag set during block 908 of FIG. 1014 and FIG. 1016 when the risk of explosion is pre-detected and mitigated. Figure 4 Memory 402 and / or Figure 5 If the leak and fire mitigation circuit 616 determines that an explosion risk has been detected, the operation 1000 proceeds to block 1014. If the leak and fire mitigation circuit 616 determines that no explosion risk has been detected, the operation 1000 proceeds to block 1020.

[0132] At block 1014, the system interface circuit 618 determines whether the hydrogen supply of the fuel distribution system 102 is enabled. For example, the system interface circuit 618 may determine when the hydrogen supply of the fuel distribution system 102 was previously disabled (e.g., during execution of block 1016, during execution of block 1004, etc.). Additionally or alternatively, the system interface circuit 618 may determine when the hydrogen supply of the fuel distribution system 102 is enabled based on outputs of sensors associated with the fuel distribution system 102, the tank 104, and / or the gas turbine engine 106. If the system interface circuit 618 determines that the hydrogen supply of the fuel distribution system 102 is enabled, the operation 1000 proceeds to block 1016. If the system interface circuit 618 determines that the hydrogen supply of the fuel distribution system 102 is not enabled (e.g., disabled, etc.), the operation 1000 proceeds to block 1018.

[0133] At block 1016, system interface circuit 618 disables the supply of hydrogen to fuel distribution system 102. For example, system interface circuit 618 may close valves within fuel distribution system 102 and / or tank 104 to prevent hydrogen fuel from flowing into gas turbine engine 106. Additionally or alternatively, system interface circuit 618 may stop operating a pump of fuel distribution system 102 and / or tank 104 to stop fuel from flowing through fuel distribution system 102 and / or tank 104.

[0134] At block 1018, the system interface circuit 618 releases the frangible panel to increase the ventilation rate of the lower hood 212. For example, the system interface circuit 618 may release a portion of the core frame 204 into the bypass 211 to increase ventilation of the lower hood 212 and dissipate hydrogen within the lower hood 212, which mitigates a potential explosion risk of the lower hood 212. An example releasable frangible panel system is described in U.S. Patent Application No. 17 / 959,400, which is incorporated herein by reference in its entirety.

[0135] At block 1020, the leak and fire mitigation circuit 616 determines whether a fire risk has been detected. For example, the leak and fire mitigation circuit 616 may access (e.g., read, etc.) Figure 4 Memory 402 and / or Figure 5 memory 502 to determine when a marker indicating a LFL at a location within the lower cover 212 is exceeded (e.g., during execution of Figure 8 The flag set during block 818 of Fig. 9 Additionally or alternatively, the leak and fire mitigation circuit 616 may cause the fuel distribution controller circuit 108 to perform operation 800 and / or operation 900 to determine when a fire risk exists within the lower hood 212. In some such examples, the leak and fire mitigation circuit 616 may remove the fire risk when a fire risk is pre-detected and mitigated by performing blocks 1022 and 1024. Figure 4 Memory 402 and / or Figure 5 If the leak and fire mitigation circuit 616 determines that a fire risk has been detected, the operation 1000 proceeds to block 1022. If the leak and fire mitigation circuit 616 determines that no fire risk has been detected, the operation 1000 ends and / or returns to Figure 7 Operation 700.

[0136] At block 1022, the system interface circuit 618 determines Figure 3 The system interface circuit 618 can determine whether the ventilation system 310 is operating at a maximum level. For example, the system interface circuit 618 can determine when each controllable element of the ventilation system 310 (e.g., air flow valve, fan, opening with controllable size, etc.) is in a position that maximizes the ventilation rate of the lower cover 212 into the bypass 211. If the system interface circuit 618 determines Figure 3 If the ventilation system 310 is operating at the maximum level, the operation 1000 proceeds to block 1026. Figure 3 If the ventilation system 310 is not operating at a maximum level, the operation 1000 proceeds to block 1024. At block 1024, the system interface circuit 618 increases the ventilation rate of the ventilation system 310. For example, the system interface circuit 618 may operate a controllable element of the ventilation system 310 to increase ventilation of the lower hood 212. In some examples, the system interface circuit 618 may increase the ventilation by a fixed amount. In other examples, the system interface circuit 618 may increase the ventilation rate to a maximum ventilation rate.

[0137] At block 1026, the system interface circuit 618 determines whether the hydrogen fuel pressure of the fuel distribution system 102 is above a threshold pressure. For example, the system interface circuit 618 may determine whether the hydrogen fuel pressure of the fuel distribution system 102 is above a threshold pressure based on one or more operating parameters 406 (e.g., fuel system parameters 424, etc.) and / or Figure 2 The system interface circuit 618 may determine the fuel pressure of the fuel distribution system 102 based on the output of the fuel line sensor 226. In some examples, the system interface circuit 618 may determine when the fuel pressure of the fuel distribution system 102 is above the minimum operating pressure of the gas turbine engine 106. In other examples, the system interface circuit 618 may compare the fuel pressure to any other suitable threshold (e.g., an operator set threshold, a regulation-based threshold, etc.). If the system interface circuit 618 determines that the hydrogen fuel pressure of the fuel distribution system 102 is above the threshold pressure, the operation 1000 proceeds to block 1028. If the system interface circuit 618 determines that the hydrogen fuel pressure of the fuel distribution system 102 is not above (e.g., equal to, less than, etc.) the threshold pressure, the operation 1000 proceeds to block 1030.

[0138] At box 1028, system interface circuit 618 reduces the hydrogen fuel pressure of fuel distribution system 102. For example, system interface circuit 618 may operate a pump of fuel distribution system 102 and / or a valve of fuel distribution system 102 to reduce the pressure of the hydrogen fuel therein. In some examples, system interface circuit 618 may reduce the fuel pressure to a threshold pressure associated with executing box 1026. In other examples, system interface circuit 618 may reduce the fuel pressure by a fixed amount. At box 1030, system interface circuit 618 disables the supply of hydrogen to fuel distribution system 102. For example, system interface circuit 618 may close a valve within fuel distribution system 102 and / or tank 104 to prevent hydrogen fuel from flowing into gas turbine engine 106. Additionally or alternatively, system interface circuit 618 may stop operating a pump of fuel distribution system 102 and / or tank 104 to stop fuel from flowing through fuel distribution system 102 and / or tank 104. Operation 1000 ends and / or returns to Figure 7 Operation 700.

[0139] Fig.11 is a block diagram of an example programmable circuit platform 1100 that is configured to execute and / or instantiate Figure 7-10 Example machine readable instructions and / or example operations to implement Figure 6 The programmable circuit platform 1100 may be, for example, a server, a personal computer, a workstation, a self-learning machine (e.g., a neural network), a mobile device (e.g., a cellular phone, a smart phone, an iPad, etc.) TM tablet computer), personal digital assistant (PDA), Internet appliance, DVD player, CD player, headphones (e.g., augmented reality (AR) headsets, virtual reality (VR) headsets, etc.) or other wearable devices, or any other type of computing and / or electronic device.

[0140] The programmable circuit platform 1100 of the illustrated example includes a programmable circuit 1112. The programmable circuit 1112 of the illustrated example is hardware. For example, the programmable circuit 1112 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. The programmable circuit 1112 can be implemented by one or more semiconductor-based (e.g., silicon-based) devices. In this example, the programmable circuit 1112 implements the sensor interface circuit 602, the memory interface circuit 604, the fire detector circuit 606, the threshold determiner circuit 608, the under-hood condition predictor circuit 610, the hydrogen concentration predictor circuit 612, the threshold comparator circuit 614, and the system interface circuit 618.

[0141] The programmable circuit 1112 of the illustrated example includes a local memory 1113 (e.g., cache, registers, etc.). The programmable circuit 1112 of the illustrated example communicates with main memories 1114 and 1116 via a bus 1118. The main memories 1114 and 1116 include a volatile memory 1114 and a non-volatile memory 1116. The volatile memory 1114 may be composed of a synchronous dynamic random access memory (SDRAM), a dynamic random access memory (DRAM), Dynamic Random Access Memory The non-volatile memory 1116 may be implemented by flash memory and / or any other desired type of memory device. Access to the main memories 1114, 1116 of the illustrated example is controlled by a memory controller 1117. In some examples, the memory controller 1117 may be implemented by one or more integrated circuits, logic circuits, microcontrollers from any desired family or manufacturer, or any other type of circuit to manage the flow of data to and from the main memories 1114, 1116.

[0142] The programmable circuit platform 1100 of the illustrated example also includes an interface circuit 1120. The interface circuit 1120 may be implemented by hardware according to any type of interface standard, such as an Ethernet interface, a universal serial bus (USB) interface, interface, a near field communication (NFC) interface, a peripheral component interconnect (PCI) interface, and / or a peripheral component interconnect express (PCIe) interface.

[0143] In the example shown, one or more input devices 1122 are connected to the interface circuit 1120. The input devices 1122 allow a user (e.g., a human user, a machine user, etc.) to input data and / or commands to the programmable circuit 1112. The input devices 1122 may be implemented by, for example, an audio sensor, a microphone, a camera (still or video), a keyboard, buttons, a mouse, a touch screen, a track pad, a track ball, an isopoint device, and / or a voice recognition system.

[0144] One or more output devices 1124 are also connected to the interface circuit 1120 of the illustrated example. The output device 1124 can be implemented, for example, by a display device (e.g., a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display (LCD), a cathode ray tube (CRT) display, an in-place switching (IPS) display, a touch screen, etc.), a tactile output device, a printer, and / or a speaker. Therefore, the interface circuit 1120 of the illustrated example typically includes a graphics driver card, a graphics driver chip, and / or a graphics processor circuit (e.g., a GPU).

[0145] The interface circuitry 1120 of the illustrated example also includes communication devices, such as transmitters, receivers, transceivers, modems, residential gateways, wireless access points, and / or network interfaces, to facilitate the exchange of data with external machines (e.g., any type of computing device) via the network 1126. Communications may be via, for example, an Ethernet connection, a digital subscriber line (DSL) connection, a telephone line connection, a coaxial cable system, a satellite system, a beyond-line-of-sight wireless system, a line-of-sight wireless system, a cellular telephone system, an optical connection, etc.

[0146] The programmable circuit platform 1100 of the illustrated example also includes one or more mass storage disks or devices 1128 to store firmware, software and / or data. Examples of such mass storage disks or devices 1128 include magnetic storage devices (e.g., floppy disks, drives, HDDs, etc.), optical storage devices (e.g., Blu-ray disks, CDs, DVDs, etc.), RAID systems, and / or solid-state storage disks or devices (e.g., flash memory devices and / or SSDs).

[0147] Can be Figure 7-10 The machine-readable instructions 1132 implemented by the machine-readable instructions may be stored in the mass storage device 1128, in the volatile memory 1114, in the non-volatile memory 1116, and / or on at least one non-transitory computer-readable storage medium (e.g., a CD or DVD), which may be removable.

[0148] As can be appreciated from the foregoing, example systems, apparatus, articles, and methods for detecting and mitigating leaks and fires detected within a gas turbine engine have been disclosed. The examples disclosed herein reduce the likelihood of adverse effects, such as fires, from hydrogen leaks within an engine underhood. The examples disclosed herein reduce potential fuel waste from undetected fuel leaks within a gas turbine engine. Thus, the disclosed systems, apparatus, articles, and methods relate to one or more improvements to the operation of a machine, such as a gas turbine engine.

[0149] Leak detection and mitigation for hydrogen fueled aircraft is disclosed herein. Further examples and combinations are provided by the subject matter of the following clauses:

[0150] A device, comprising: machine-readable instructions; and programmable circuitry, the programmable circuitry being used to instantiate the machine-readable instructions or execute at least one of the machine-readable instructions, for: determining a hydrogen concentration threshold value for a location within a lower cowling of an engine of the aircraft based on an engine condition of the aircraft; determining a hydrogen concentration at the location based on an output of a hydrogen concentration sensor within the lower cowling; comparing the hydrogen concentration with the hydrogen concentration threshold value; and performing a mitigation action in a hydrogen fuel distribution system based on the comparison of the hydrogen concentration with the hydrogen concentration threshold value.

[0151] An apparatus as described in any preceding clause, wherein the engine condition includes at least one of a mission phase of the aircraft, a fuel pressure, a fuel flow rate, an airflow rate in the lower cowl, a temperature of the lower cowl, an altitude of the aircraft, or a speed of the engine of the aircraft.

[0152] An apparatus as in any preceding clause, wherein the programmable circuit determines the hydrogen concentration threshold based on a lower flammability limit of hydrogen at the location.

[0153] An apparatus as described in any preceding clause, wherein the location is remote from the hydrogen concentration sensor, and the programmable circuit is further used to: predict the temperature and pressure at the location; and determine the lower flammability limit at the location based on the temperature and the pressure.

[0154] An apparatus as described in any preceding clause, wherein the programmable circuit is used to perform the mitigating action in the hydrogen fuel distribution system by at least one of: increasing the ventilation rate of the hydrogen fuel distribution system; or reducing the fuel pressure of the hydrogen fuel distribution system.

[0155] The apparatus of any preceding clause, wherein the location is remote from the hydrogen concentration sensor, and the programmable circuit is further configured to: predict a temperature and a pressure at the location; and determine a lower explosion limit of hydrogen at the location based on the temperature and the pressure.

[0156] An apparatus as described in any preceding clause, wherein the programmable circuit is used to perform the mitigation action in the hydrogen fuel dispensing system by at least one of: disabling the hydrogen fuel dispensing system; or activating a frangible panel system.

[0157] A non-transitory computer-readable medium including instructions that, when executed, cause a programmable circuit to: determine a hydrogen concentration threshold for a location within a lower cowling of an engine of the aircraft based on an engine condition of the aircraft; determine a hydrogen concentration at the location based on an output of a hydrogen concentration sensor within the lower cowling; compare the hydrogen concentration to the hydrogen concentration threshold; and perform a mitigation action in a hydrogen fuel distribution system based on the comparison of the hydrogen concentration to the hydrogen concentration threshold.

[0158] A non-transitory machine-readable storage medium as described in any preceding clause, wherein the engine condition comprises at least one of a mission phase of the aircraft, a fuel pressure, a fuel flow rate, an airflow rate in the lower cowl, a temperature of the lower cowl, an altitude of the aircraft, or a speed of the engine of the aircraft.

[0159] The non-transitory machine-readable storage medium of any preceding clause, wherein the instructions, when executed, cause the programmable circuit to determine the hydrogen concentration threshold based on a lower flammability limit of hydrogen at the location.

[0160] A non-transitory machine-readable storage medium according to any preceding clause, wherein the location is remote from the hydrogen concentration sensor, and the instructions, when executed, cause the programmable circuit to: predict a temperature and a pressure at the location; and determine the lower flammability limit at the location based on the temperature and the pressure.

[0161] A non-transitory machine-readable storage medium according to any preceding clause, wherein the instructions, when executed, cause the programmable circuit to perform the mitigation action in the hydrogen fuel distribution system by at least one of: increasing the ventilation rate of the hydrogen fuel distribution system; or reducing the fuel pressure of the hydrogen fuel distribution system.

[0162] The non-transitory machine-readable storage medium of any preceding clause, wherein the location is remote from the hydrogen concentration sensor, and the instructions, when executed, cause the programmable circuit to further: predict a temperature and a pressure at the location; and determine a lower explosion limit of hydrogen at the location based on the temperature and the pressure.

[0163] The non-transitory machine-readable storage medium of any preceding clause, wherein the instructions, when executed, cause the programmable circuit to perform the mitigation action in the hydrogen fuel dispensing system by at least one of: disabling the hydrogen fuel dispensing system; or activating a frangible panel system.

[0164] A method for operating a hydrogen fuel distribution system for an aircraft, the method comprising: determining a hydrogen concentration threshold for a location within a lower cowling of an engine of the aircraft based on an engine condition of the aircraft; determining a hydrogen concentration at the location based on an output of a hydrogen concentration sensor within the lower cowling; comparing the hydrogen concentration to the hydrogen concentration threshold; and operating the hydrogen fuel distribution system based on the comparison of the hydrogen concentration and the hydrogen concentration threshold.

[0165] A method as in any preceding clause, wherein the determination of the hydrogen concentration threshold is based on a lower flammability limit of hydrogen at the location.

[0166] A method as claimed in any preceding clause, wherein the location is remote from the hydrogen concentration sensor, the method comprising: predicting a temperature and a pressure at the location; and determining the lower flammability limit at the location based on the temperature and the pressure.

[0167] The method of any preceding clause, wherein operating the hydrogen fuel dispensing system comprises at least one of: increasing a ventilation rate of the hydrogen fuel dispensing system; or decreasing a fuel pressure of the hydrogen fuel dispensing system.

[0168] A method according to any preceding clause, wherein the location is remote from the hydrogen concentration sensor, the method comprising: predicting a temperature and a pressure at the location; and determining a lower explosion limit of hydrogen at the location based on the temperature and the pressure.

[0169] The method of any preceding clause, wherein operating the hydrogen fuel dispensing system comprises at least one of: disabling the hydrogen fuel dispensing system; or activating a frangible panel system.

[0170] The following claims are incorporated into this detailed description by this reference. Although certain example systems, devices, articles, and methods have been disclosed herein, the coverage of this patent is not limited thereto. On the contrary, this patent covers all systems, devices, articles, and methods that fully fall within the scope of the claims of this patent.

Claims

1. A device, characterized in that: include: machine-readable instructions; and programmable circuitry for at least one of instantiating the machine-readable instructions or executing the machine-readable instructions to: determining a hydrogen concentration threshold value for a location within a lower cowling of an engine of the aircraft based on an engine condition of the aircraft; determining the hydrogen concentration at the location based on an output of a hydrogen concentration sensor in the lower cover; comparing the hydrogen concentration to the hydrogen concentration threshold; and Based on the comparison of the hydrogen concentration and the hydrogen concentration threshold, a mitigation action is performed in the hydrogen fuel distribution system.

2. The device according to claim 1, characterized in that The engine condition comprises at least one of a mission phase of the aircraft, a fuel pressure, a fuel flow rate, an airflow rate in the lower cowl, a temperature of the lower cowl, an altitude of the aircraft, or a speed of the engine of the aircraft.

3. The device according to claim 1, characterized in that Wherein the programmable circuit determines the hydrogen concentration threshold based on a lower flammability limit of hydrogen at the location.

4. The device according to claim 3, characterized in that wherein the location is remote from the hydrogen concentration sensor, and the programmable circuit is further configured to: predicting the temperature and pressure at the location; and The lower flammability limit at the location is determined based on the temperature and the pressure.

5. The device according to claim 3, characterized in that wherein the programmable circuit is configured to perform the mitigation action in the hydrogen fuel dispensing system by at least one of: increasing the ventilation rate of the hydrogen fuel distribution system; or The fuel pressure of the hydrogen fuel distribution system is reduced.

6. The device according to claim 1, characterized in that wherein the location is remote from the hydrogen concentration sensor, and the programmable circuit is further configured to: predicting the temperature and pressure at the location; and Based on the temperature and the pressure, a lower explosion limit of hydrogen at the location is determined.

7. The device according to claim 6, characterized in that wherein the programmable circuit is configured to perform the mitigation action in the hydrogen fuel dispensing system by at least one of: disabling the hydrogen fuel dispensing system; or Activate the breakable panel system.

8. A non-transitory computer-readable medium comprising instructions, characterized in that: The instructions, when executed, cause the programmable circuit to: determining a hydrogen concentration threshold value for a location within a lower cowling of an engine of the aircraft based on an engine condition of the aircraft; determining the hydrogen concentration at the location based on an output of a hydrogen concentration sensor in the lower cover; comparing the hydrogen concentration to the hydrogen concentration threshold; and Based on the comparison of the hydrogen concentration and the hydrogen concentration threshold, a mitigation action is performed in the hydrogen fuel distribution system.

9. The non-transitory computer-readable medium of claim 8, wherein: The engine condition comprises at least one of a mission phase of the aircraft, a fuel pressure, a fuel flow rate, an airflow rate in the lower cowl, a temperature of the lower cowl, an altitude of the aircraft, or a speed of the engine of the aircraft.

10. The non-transitory computer readable medium of claim 8, wherein: Wherein the instructions, when executed, cause the programmable circuit to determine the hydrogen concentration threshold based on a lower flammability limit of hydrogen at the location.

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