Abstract: Example integrated cryogenic hydrogen tank systems and methods for operating the same are disclosed herein. An example system comprises a first cryogenic tank coupled to a second cryogenic tank via a liquid hydrogen (LH2) transfer flowline and a gaseous hydrogen (GH2) transfer flowline, the LH2 transfer flowline and the GH2 transfer flowline to maintain a fuel level and a vapor pressure across the system, the fuel level corresponding to a cryogenic liquid; an inlet port connected to one of the first cryogenic tank or the second cryogenic tank; an LH2 extraction flowline connected to at least one of the first or second cryogenic tanks to supply the cryogenic liquid to a fuel management system; and a pressure safety system coupled to at least one of the first or second cryogenic tanks via a GH2 extraction flowline.

Abstract: Methods, apparatus, systems, and articles of manufacture to produce cryo-compressed hydrogen are disclosed. An example cryo-compressed hydrogen production system includes a compressor to compress an input of hydrogen, at least one heat exchanger to cool the hydrogen, and a conduit to convey the hydrogen at least partially to a storage tank for storage at a temperature less than or equal to a first threshold and greater than a second threshold, the first threshold defined by an upper temperature limit for cryo-compressed hydrogen, the second threshold defined by a hydrogen liquefaction temperature.

Abstract: A system includes a hydrogen sensor configured to generate data indicative of a level of hydrogen present within the compartment and a computing system. The computing system configured to determine at least one of the level of hydrogen present within the compartment or a rate of change of the level of hydrogen present within the compartment and compare the determined at least one of the level of hydrogen present within the compartment or the rate of change of the level of hydrogen present within the compartment to an associated threshold value. Furthermore, when the determined at least one of the level of hydrogen present within the compartment or the rate of change of the level of hydrogen present within the compartment exceeds the associated threshold value, the computing system is configured to initiate a control action associated with reducing the level of hydrogen present within the compartment.

Abstract: A gas turbine engine is provided defining an axial direction, a radial direction, and a circumferential direction. The gas turbine engine includes a turbomachine having a compressor section, a combustion section, and a turbine section in serial flow order; a fan section including a fan rotatable by the turbomachine; a nacelle enclosing the fan; and an oil tank positioned within the nacelle, wherein the oil tank defines an effective length (LT) along the axial direction, a circumference span (CS) along the circumferential direction, and a radial height (?rT) along the radial direction, and wherein these parameters are related by a tank sizing factor (TSF) equal to the effective length (LT) times the circumference span (CS) divided by the radial height (?rT) squared LT×CS/?rT2), wherein the tank sizing factor (TSF) is between 20 and 2200.

Abstract: Systems and methods are disclosed for estimating or determining a rate or an amount of fuel coke formation in a fuel system, such as of a gas turbine engine. The system is operable to control a rate of fuel coke formation. The system may include a sensor that measures an operating parameter associated with fuel coke formation in the fuel system. A controller is in communication with the sensor to receive the signal therefrom for determining an amount or a rate of fuel coking in the fuel system. Based on this determination the controller may adjust the rate of fuel coke formation by adjusting the operation of the turbine engine, a thermal management system of the turbine engine, or the fuel system.

Abstract: Methods, apparatus, systems, and articles of manufacture are disclosed herein that include a cryogenic pump system comprising: a cryogenic liquid tank; a cryogenic pump including a suction adapter, the suction adapter connected to the cryogenic liquid tank via a liquid supply line and a gaseous return line; and a phase separator connected downstream of the cryogenic liquid tank and upstream of the cryogenic pump, the phase separator including a filtration structure integrated into the liquid supply line to separate vapor from cryogenic liquid, the phase separator connected to the gaseous return line to direct the vapor to the cryogenic liquid tank.

Abstract: A minimum creep life location (MCLL) on a blade for a turbine blade design is received. A temperature at the MCLL on the blade is monitored. When the temperature at the MCLL exceeds a predetermined threshold, a cooling air supply is adjusted to lower the temperature below the threshold during engine operation.

Abstract: A cryogenic system includes a cryogenic tank containing a liquid cryogen and a vacuum vessel surrounding the cryogenic tank and providing a vacuum space between an inner surface of the vacuum vessel and an outer surface of the cryogenic tank. The cryogenic system further includes a suspension system arranged within the vacuum space so as to support the cryogenic tank within the vacuum vessel and to maintain the cryogenic tank within the vacuum vessel in a desired position. The suspension system includes a plurality of roller elements arranged within the vacuum space and contacting the inner surface of the vacuum vessel and the outer surface of the cryogenic tank.

Abstract: An apparatus to refuel a vessel with cryo-compressed hydrogen is disclosed herein. The apparatus includes a refueler controller configured to defuel the vessel prior to a refuel process based on a pressure of the vessel; fill a mixing tank with at least the cryo-compressed hydrogen based on the pressure of the vessel and a pressure of the mixing tank, wherein the mixing tank is connected upstream of the vessel and is structured to include the cryo-compressed hydrogen; initiate the refuel process of the vessel; adjust a temperature of the mixing tank in response to a temperature of the vessel not satisfying a target temperature of the vessel during the refuel process, wherein the temperature of the mixing tank is to be adjusted based on an increase or a decrease of flow of supercritical hydrogen; and end the refuel process in response to the pressure of the vessel satisfying a target pressure of the vessel.

Abstract: Systems and methods are disclosed for estimating or determining a rate or an amount of fuel coke formation in a fuel system, such as of a gas turbine engine. The system is operable to control a rate of fuel coke formation. The system may include a sensor that measures an operating parameter associated with fuel coke formation in the fuel system. A controller is in communication with the sensor to receive the signal therefrom for determining an amount or a rate of fuel coking in the fuel system. Based on this determination the controller may adjust the rate of fuel coke formation by adjusting the operation of the turbine engine, a thermal management system of the turbine engine, or the fuel system.

Abstract: A heat exchanger for a hydrogen fuel delivery system includes a tube bank including an inner-tube where a first portion of the inner-tube extends through an inlet region of the tube bank, a second portion of the inner-tube extends through a mid-region of the tube bank, and a third portion of the inner-tube extends through an outlet region of the tube bank. A thermal buffer at least partially surrounds the inner-tube. A first portion of the thermal buffer extends along the first portion of the inner-tube, a second portion of the thermal buffer extends along the second portion of the inner-tube, and a third portion of the thermal buffer extends along the third portion of the inner-tube. A plurality of fins is disposed along the inner-tube and extends radially outwardly from an outer surface of the thermal buffer.

Abstract: A turbofan engine includes a fan, a core turbine engine, and a thermal management system. The thermal management system has a thermal transport bus along which a working fluid is movable, one or more heat-source heat exchangers positioned along the thermal transport bus, and one or more heat-sink heat exchangers arranged in fluid communication with the one or more heat-source heat exchangers via the thermal transport bus. The thermal transport bus has a thermal transport bus capacity determined by multiplying a propulsive effectiveness factor associated with the turbofan engine by a heat load factor associated with the thermal transport bus. The thermal transport bus capacity is between 0.07 and 33.65 for an overall inlet temperature of the working fluid at an overall inlet of the one or more heat-source heat exchangers being between 31 and 200 degrees Celsius and the propulsive effectiveness factor being between 0.52 and 1.37.

Abstract: A fuel cell power system for a vehicle having a propulsor is provided herein. The propulsor is configured to generate thrust for the vehicle and a flow of compressed air. The fuel cell power system includes a fuel delivery system for providing a flow of hydrogen fuel and a fuel cell stack and is configured to be located remotely from the propulsor and in airflow communication with the propulsor for receiving the flow of compressed air from the propulsor. The fuel delivery system further includes a fuel tank for storing hydrogen fuel and the fuel cell stack is further in fluid communication with the fuel delivery system for receiving the flow of hydrogen fuel from the fuel delivery system.

Abstract: Methods and apparatus are for monitoring systems for hydrogen fueled aircraft. An example fuel distribution system distribution system includes a first hydrogen fuel tank, a first sensor associated with the first hydrogen fuel tank, a second sensor associated with the combustor, and a controller to determine a first rate of change in a first amount of hydrogen in the first hydrogen fuel tank based on a first input from the first sensor, determine a flow rate of hydrogen into the combustor based on a second input from the second sensor, determine an average mass loss rate based on the first rate of change and the flow rate and in response to determining the average mass loss rate satisfies a first threshold, determine a leak is present in the fuel distribution system.

Abstract: Methods and apparatus are disclosed for a hydrogen aircraft with cryo-compressed storage. An example fuel distribution system includes a vacuum vessel, a cryogenic vessel positioned within the vacuum vessel, the cryogenic vessel part of a cryo-compressed hydrogen delivery assembly, and at least one of a heater or a thermosiphoning loop to maintain a pressure of the cryogenic vessel.

Abstract: An apparatus to refuel a vessel with cryo-compressed hydrogen is disclosed herein. The apparatus includes a refueler controller configured to defuel the vessel prior to a refuel process based on a pressure of the vessel; fill a mixing tank with at least the cryo-compressed hydrogen based on the pressure of the vessel and a pressure of the mixing tank, wherein the mixing tank is connected upstream of the vessel and is structured to include the cryo-compressed hydrogen; initiate the refuel process of the vessel; adjust a temperature of the mixing tank in response to a temperature of the vessel not satisfying a target temperature of the vessel during the refuel process, wherein the temperature of the mixing tank is to be adjusted based on an increase or a decrease of flow of supercritical hydrogen; and end the refuel process in response to the pressure of the vessel satisfying a target pressure of the vessel.

Abstract: Methods and apparatus are disclosed for a hydrogen-based fuel distribution system using a submerged pump and compressed natural gas. An example fuel distribution system includes a gaseous hydrogen fuel tank for holding a first portion of hydrogen fuel in a gaseous phase as part of a gaseous hydrogen delivery assembly, and a liquid hydrogen fuel tank for holding a second portion of hydrogen fuel in a liquid phase as part of a liquid hydrogen delivery assembly, the liquid hydrogen fuel tank including a primary tank and a secondary tank, the secondary tank including a submerged pump, wherein the gaseous hydrogen fuel tank and the liquid hydrogen fuel tank are in a parallel arrangement.

Abstract: An engine control system may be configured to perform a method of controlling thermal bias in a turbomachine. An exemplary method may include determining a thermal bias-value for the turbomachine, and performing a cooling treatment based at least in part on the thermal bias-value. The thermal bias-value may include a difference between an upward temperature-value corresponding to a first one or more temperature measurements of an upward portion of the turbomachine and a downward temperature-value corresponding to a second one or more temperature measurements of a downward portion of the turbomachine. The cooling treatment may include at least one of: circulating air through at least a portion of the turbomachine, and rotating a shaft of the turbomachine with a motoring system.

Abstract: A gas turbine engine is provided having: a turbomachine; a fan section having a fan rotatable by the turbomachine; a nacelle enclosing the fan; and an engine controller positioned within the nacelle. The nacelle defines an inner surface radius (r) along the radial direction inward of the engine controller, wherein the engine controller defines a radial height (?r) along the radial direction, a total volume (V), and a normalized radius (r?). The normalized radius (r?) is a ratio of the inner surface radius (r) to the total volume (V) to cube root, and wherein these parameters are related by the following equation: 0.1 r ? ? 1 < ? r r < K r ? ? 4 / 3 . wherein the normalized radius (r?) is between 1.25 and 8 and K is equal to 40%, or the normalized radius (r?) is between 2.75 and 4.5 and K is equal to 65%.

Abstract: An orifice assembly includes a first member defining an orifice having a first dimension in a compressed state and a thermally-sensitive material arranged adjacent to the first member. The thermally-sensitive material has a rigid, first state that applies force to the first member so as to maintain the first dimension of the orifice in the compressed state and a flexible, second state configured to release the force applied to the first member. As such, when subjected to temperatures above a predetermined temperature threshold, the thermally-sensitive material changes from the rigid, first state to the flexible, second state to allow the first dimension of the first member in the compressed state to passively expand to a decompressed, second dimension, the second dimension being larger than the first dimension.