Abstract: A system for energy conversion that includes a propulsion system, a fuel circuit, a combustion device, a turbine, and a load device. The fuel circuit is in fluid communication with a fuel tank and a fuel flow control device that separates a flow of fuel into a first portion and a second portion. The combustion device receives a flow of oxidizer and the second portion of fuel to generate combustion gases. The turbine receives the combustion gases from the combustion device via a fluid circuit. The load device is operably coupled to the turbine via a driveshaft and is configured to receive torque from the driveshaft.

Abstract: A method is provided for operating a thermal management system of a gas turbine engine. The method includes: operating the gas turbine engine to start-up the gas turbine engine; receiving data indicative of a state of a thermal transport bus of the thermal management system using a sensor, the state of the thermal transport bus including a phase of a thermal fluid within the thermal transport bus; and starting a pump of a pump assembly in response to receiving data indicative of the state of the thermal transport bus of the thermal management system, the pump in fluid communication with the thermal transport bus.

Abstract: A vehicle is provided including a structure including a skin defining an outside surface exposed to ambient cooling flow and an inside surface. The structure includes a first structural member extending from the inside surface of the skin and a second structural member extending from the inside surface of the skin; and a thermal management system including a heat exchanger assembly positioned adjacent to, and in thermal communication with, the inside surface of the skin, the heat exchanger assembly positioned at least partially between the first and second structural members of the structure.

Abstract: A system for controlling blade clearances within a gas turbine engine includes a rotor disk and a rotor blade coupled to the rotor disk. Additionally, the system includes an outer turbine component positioned outward of the rotor blade such that a clearance is defined between the rotor blade and the outer turbine component. Furthermore, the system includes a heat exchanger configured to receive a flow of cooling air bled from the gas turbine engine and transfer heat from the received flow of the cooling air to a flow of coolant to generate cooled cooling air. Moreover, the system includes a valve configured to control the flow of the coolant to the heat exchanger. In this respect, the cooled cooling air is supplied to at least one of the rotor disk or the rotor blade to adjust the clearance between the rotor blade and the outer turbine component.

Abstract: A heat engine comprising a compressor providing a flow of compressed air from a core flowpath of the heat engine; a cooled cooling air (CCA) heat exchanger system to which the flow of compressed air is provided from the compressor; a coolant supply system providing a flow of coolant to the CCA heat exchanger in thermal communication with the flow of compressed air at the CCA heat exchanger, in which the coolant supply system and CCA heat exchanger together define a CCA circuit through which the compressed air flows in thermal communication with the coolant; and a hot section disposed downstream of the compressor section along the core flowpath through which combustion gases flow, in which the hot section defines a secondary flowpath through which the flow of compressed air from the CCA heat exchanger is provided.

Abstract: A heat exchanger and heat exchanger core are provided. The heat exchanger core includes a plurality of columnar passages extending between an inlet plenum of the heat exchanger core and an outlet plenum of the heat exchanger core, the columnar passages formed monolithically in a single fabrication process.

Abstract: Heat exchangers, heat exchanger systems, and hypersonic vehicles are provided. For example, a heat exchanger is provided that comprises a first chamber for receipt of a flow of cool fluid and a second chamber for receipt of a flow of hot fluid. The heat exchanger further comprises a buffer fluid flowpath for circulation of a buffer fluid therethrough. The buffer fluid circulates within the buffer fluid flowpath disposed between the first chamber and the second chamber to transfer heat from the hot fluid to the cool fluid. In certain embodiments, a hypersonic vehicle comprises such a heat exchanger, and the cool fluid is cryogenic or near-cryogenic fuel of the hypersonic vehicle and the hot fluid is engine bleed air from a hypersonic propulsion engine of the vehicle.

Abstract: A method of manufacturing a heat exchanger is provided. The method includes forming a first substrate by additively manufacturing a body defining a first outer surface and a second outer surface opposite the first outer surface, a first partial fluid flow channel formed within the first outer surface, a second partial fluid flow channel formed within the second outer surface, and at least one internal fluid flow channel completely formed within the body, and coupling the first substrate to a second substrate including a partial fluid flow channel formed within a surface of the second substrate such that the first partial fluid flow channel of the first substrate and the partial fluid flow channel of the second substrate combine to form a combined fluid flow channel.

Abstract: A gas supply system is provided herein. The gas supply system includes a fuel oxygen reduction unit having a circuit defining a gas flowpath for a flow of a stripping gas. A reservoir is in selective fluid communication with the fuel oxygen reduction unit and is configured to store a portion of the stripping gas from the circuit. The reservoir is further configured to be in selective fluid communication with the fuel system component when installed in a vehicle to provide the stored portion of the stripping gas to the fuel system component in response to detection of a purge condition.

Abstract: A method for thermal management for an aircraft includes extracting a flow of compressed fluid from a compressor section of a propulsion system. The flow of compressed fluid is passed through an anti-ice system. The flow of compressed fluid flows from the anti-ice system to a turbine. The flow of compressed fluid is expanded across the turbine. The expanded flow of compressed fluid then flows to thermal communication with a thermal load.

Abstract: A vehicle is provided including a structure including a skin defining an outside surface exposed to ambient cooling flow and an inside surface. The structure includes a first structural member extending from the inside surface of the skin and a second structural member extending from the inside surface of the skin; and a thermal management system including a heat exchanger assembly positioned adjacent to, and in thermal communication with, the inside surface of the skin, the heat exchanger assembly positioned at least partially between the first and second structural members of the structure.

Abstract: A system for energy conversion that includes a propulsion system, a fuel circuit, a combustion device, a turbine, and a load device. The fuel circuit is in fluid communication with a fuel tank and a fuel flow control device that separates a flow of fuel into a first portion and a second portion. The combustion device receives a flow of oxidizer and the second portion of fuel to generate combustion gases. The turbine receives the combustion gases from the combustion device via a fluid circuit. The load device is operably coupled to the turbine via a driveshaft and is configured to receive torque from the driveshaft.

Abstract: A thermal device includes a plate defining a plurality of convex curves and a plurality of concave curves. Each convex curve is positioned between a pair of adjacent concave curves of the plurality of concave curves. Each concave curve is positioned between a pair of adjacent convex curves of the plurality of convex curves. Each concave curve defines a vertex. The thermal device also includes a plurality of pins. Each pin of the plurality of pins extends from the vertex of a different concave curve of the plurality of concave curves and extends away from the plate.

Abstract: A heat engine comprising a compressor providing a flow of compressed air from a core flowpath of the heat engine; a cooled cooling air (CCA) heat exchanger system to which the flow of compressed air is provided from the compressor; a coolant supply system providing a flow of coolant to the CCA heat exchanger in thermal communication with the flow of compressed air at the CCA heat exchanger, in which the coolant supply system and CCA heat exchanger together define a CCA circuit through which the compressed air flows in thermal communication with the coolant; and a hot section disposed downstream of the compressor section along the core flowpath through which combustion gases flow, in which the hot section defines a secondary flowpath through which the flow of compressed air from the CCA heat exchanger is provided.

Abstract: A method and system for bleed flow power generation is provided. The engine includes a core flowpath formed by a compressor section, a heat addition system, and an expansion section in serial flow arrangement. A bleed circuit is extended from the core flowpath to extract a portion of compressed fluid from the core flowpath. The method and system include bleeding compressed fluid through a bleed circuit extended in fluid communication from the core flowpath of the engine; flowing the compressed fluid through the bleed circuit to a turbine rotor positioned at the bleed circuit; extracting, via the turbine rotor, energy from the flow of compressed fluid across the turbine rotor; and receiving energy at an electric machine operably coupled to the turbine rotor.

Abstract: A method of detecting an airflow fault condition in a gas turbine engine, the method including: operating the gas turbine engine with a thermal transport bus having an intermediary heat exchange fluid flowing therethrough; determining a performance characteristic of the intermediary heat exchange fluid in the thermal transport bus is outside of a predetermined range, wherein the performance characteristic includes a temperature, a pressure, a flowrate, or a combination thereof; and indicating an airflow fault condition in response to determining the performance characteristic is outside of the predetermined range.

Abstract: A gas turbine engine having a waste heat recovery system is provided. The gas turbine engine includes a compressor section, a combustion section, a turbine section, and an exhaust section in serial flow order and together defining a core air flowpath, the exhaust section including a primary exhaust flowpath and a waste heat recovery flowpath parallel to the primary exhaust flowpath; and the waste heat recovery system includes a heat source exchanger positioned in thermal communication with a first portion of the waste heat recovery flowpath.

Abstract: A passive flow modulation device for a machine defining an axial direction and a radial direction, the passive flow modulation device including: a first ring with a first coefficient of thermal expansion; a second ring disposed coaxially with the first ring and positioned at least partially inward of the first ring along the radial direction, spaced from the first ring along the axial direction, or both, the first ring, the second ring, or both defining at least in part one or more passages, the second ring with a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion to passively modulate a size of the one or more passages during operation.

Abstract: A gas turbine engine is provided including a turbomachine having a compressor section, a combustion section, and a turbine section arranged in serial flow order; a rotor assembly driven by the turbomachine, the rotor assembly, the turbomachine, or both comprising a substantially annular duct relative to the centerline of the gas turbine engine, the annular duct defining a flowpath; a heat exchanger positioned within the annular duct and extending substantially continuously along the circumferential direction, the heat exchanger comprising a first material defining a heat exchange surface exposed to the flowpath, wherein the first material defines a heat exchange coefficient and wherein the heat exchange surface defines a surface area (A), and wherein the heat exchanger has an effective transmission loss (ETL) of between 5 decibels and 1 decibel for an operating condition.

Abstract: Systems and methods of operating systems are provided. For example, a system comprises a fuel cooling loop including a cold fuel flowpath having a fuel flowing therethrough, a fuel cooler heat exchanger for cooling the fuel in fluid communication with the cold fuel flowpath, and a cold fuel tank disposed along the cold fuel flowpath for accumulating at least a portion of the cooled fuel. The system further comprises a fuel heating loop including a hot fuel flowpath for a flow of the fuel, a fuel heater heat exchanger for heating the fuel in fluid communication with the hot fuel flowpath, and a hot fuel tank disposed along the hot fuel flowpath for accumulating at least a portion of the heated fuel. The fuel cooling loop is coupled to the fuel heating loop such that the fuel circulates through both the fuel cooling loop and the fuel heating loop.