Abstract: Systems and methods of aircraft thrust management are provided. For example, a propulsion system for an aircraft comprises a fuel cell assembly comprising a fuel cell, a turbomachine, and a controller comprising memory and one or more processors. The memory stores instructions that, when executed by the one or more processors, cause the propulsion system to perform operations including receiving data indicative of a propulsion system thrust discrepancy and modifying an output of the fuel cell in response to receiving data indicative of the propulsion system thrust discrepancy. Modifying the fuel cell output may include modifying output products, an electrical power output, or both of the fuel cell to balance the thrust provided by the propulsion system.

Abstract: A propulsion system is provided including: a gas turbine engine including a combustion section having a combustor; and a modular fuel cell assembly. The modular fuel cell assembly includes: a first fuel cell string comprising a first processing unit and a first fuel cell stack, the first fuel cell stack comprising a first fuel cell defining an outlet configured to provide output products from the first fuel cell to the combustor; and a second fuel cell string comprising a second processing unit and a second fuel cell stack, the second fuel cell stack comprising a second fuel cell defining an outlet configured to provide output products from the second fuel cell to the combustor.

Abstract: A combustor for a gas turbine engine, the gas turbine engine defining a longitudinal centerline extending in a longitudinal direction, a radial direction extending orthogonally outward from the longitudinal centerline, and a circumferential direction extending concentrically around the longitudinal centerline, the combustor including: a forward liner segment; an aft liner segment disposed downstream from the forward liner segment relative to a direction of flow through the combustor, the forward and aft liner segments at least partially defining a combustion chamber; and an intermediate member disposed at least partially between the forward and aft liner segments and extending in the circumferential direction.

Abstract: A hydrocarbon fluid containment article having a wall with a surface that is wetted by hydrocarbon fluid. The surface includes an anti-coking coating. The anti-coking coating includes a copper salt, a silver salt, or a combination thereof. A gas turbine engine component including a wall having a first surface and an anti-coking coating on the first surface of the wall that is wetted by hydrocarbon fluid. The anti-coking coating including a copper salt, a silver salt, or a combination thereof that prevents the formation of gum or coke on a surface thereon. Methods for reducing the deposition of thermal decomposition products on a wall of an article are also provided.

Abstract: Systems and methods include a plurality of fuel cell stacks extended around a combustion chamber. The plurality of fuel cell stacks are distributed along a length of the combustion chamber in the axial direction. The fuel cell stacks are configured to provide output products to the combustion chamber to achieve at least one of late lean injection and a desired combustor gas concentration distribution.

Abstract: Rotational atherectomy devices and systems can remove or reduce stenotic lesions in implanted grafts by rotating one or more abrasive elements within the graft. The abrasive elements can be attached to a distal portion of an elongate flexible drive shaft that extends from a handle assembly that includes a driver for rotating the drive shaft. In particular implementations, individual abrasive elements are attached to the drive shaft at differing radial angles in comparison to each other (e.g., configured in a helical array). The centers of mass of the abrasive elements can define a path that fully or partially spirals around the drive shaft.

Abstract: A combustion section defines an axial direction, a radial direction, and a circumferential direction. The combustion section includes a casing that defines a diffusion chamber. A combustion liner is disposed within the diffusion chamber and defines a combustion chamber. The combustion liner is spaced apart from the casing such that a passageway is defined between the combustion liner and the casing. A fuel cell assembly is disposed in the passageway. The fuel cell assembly includes a fuel cell stack having a plurality of fuel cells each extending between an inlet end and an outlet end. Each fuel cell of the plurality of fuel cells includes an air channel and a fuel channel each fluidly coupled to the combustion chamber.

Abstract: A combustor for a gas turbine engine, the gas turbine engine defining a longitudinal centerline extending in a longitudinal direction, a radial direction extending orthogonally outward from the longitudinal centerline, and a circumferential direction extending concentrically around the longitudinal centerline, the combustor including: a forward liner segment; an aft liner segment disposed downstream from the forward liner segment relative to a direction of flow through the combustor, the forward and aft liner segments at least partially defining a combustion chamber; and an intermediate member disposed at least partially between the forward and aft liner segments and extending in the circumferential direction.

Abstract: A combustion section defines an axial direction, a radial direction, and a circumferential direction. The combustion section includes a casing that defines a diffusion chamber. A combustion liner is disposed within the diffusion chamber and defines a combustion chamber. The combustion liner is spaced apart from the casing such that a passageway is defined between the combustion liner and the casing. A fuel cell assembly is disposed in the passageway. The fuel cell assembly includes a fuel cell stack that has a plurality of fuel cells each extending between an inlet end and an outlet end. The inlet end receives a flow of air and fuel and the outlet end provides output products to the combustion chamber. The outlet end of the plurality of fuel cells extends through the combustion liner and partially defines the combustion chamber.

Abstract: A hydrocarbon fluid containment article having a wall with a surface that is wetted by hydrocarbon fluid. The surface includes an anti-coking coating. The anti-coking coating includes a copper salt, a silver salt, or a combination thereof. A gas turbine engine component including a wall having a first surface and an anti-coking coating on the first surface of the wall that is wetted by hydrocarbon fluid. The anti-coking coating including a copper salt, a silver salt, or a combination thereof that prevents the formation of gum or coke on a surface thereon. Methods for reducing the deposition of thermal decomposition products on a wall of an article are also provided.

Abstract: A mixer assembly having a plurality of mixer vanes, each of the plurality of mixer vanes having a first end, a second end, and a body portion extending between the first end and the second end, the body portion having a length, a width, a thickness, a cross-sectional area, a curvature, and a twist, wherein each of the plurality of mixer vanes has a 3-dimensional shape defined by the length, width, thickness, cross-sectional area, curvature, and twist of the body portion, and wherein at least one of the plurality of mixer vanes has a non-uniform 3-dimensional shape.

Abstract: A swirler apparatus for a combustor, including: primary and secondary swirlers disposed axially adjacent to each other along a swirler centerline; the primary swirler including a plurality of primary swirl vanes arrayed around the swirler centerline, each primary swirl vane including opposed sides bounded between opposed forward and aft edges and opposed leading and trailing edges; wherein the forward edge is oriented at a first vane angle with respect to a radial direction; wherein the aft edge is oriented at a second vane angle with respect to the radial direction; wherein the second vane angle is different from the first vane angle; and the secondary swirler including a plurality of secondary swirl vanes arrayed around the swirler centerline.

Abstract: A method for operating a propulsion system for an aircraft, the propulsion system including a gas turbine engine and a fuel cell assembly, the fuel cell assembly including a fuel cell stack having a solid oxide fuel cell defining an outlet positioned to remove output products from the solid oxide fuel cell during operation, the method including: operating the fuel cell assembly to provide output products to a combustor of a combustion section of the gas turbine engine; and operating the fuel cell assembly, the gas turbine engine, or both such that a pressure within an anode of the solid oxide fuel cell is less than a pressure within a cathode of the solid oxide fuel cell, is less than a pressure within a combustion chamber of the gas turbine engine, or both while operating the gas turbine engine.

Abstract: A gas turbine engine includes a fuel cell assembly including a fuel cell stack and defining a fuel cell assembly operating parameter, a fuel source, and a turbomachine. The turbomachine includes a compressor section, a combustor, and a turbine section arranged in serial flow order. The combustor is configured to receive a flow of fuel from the fuel source and further configured to receive output products from the fuel cell stack. A controller is configured to perform operations including receiving data indicative of system operation conditions, determining a set of fuel cell operating conditions to move the system emission output into or maintain the system emission output within an emissions range, and controlling the fuel cell assembly operating parameter according to the determined set of fuel cell operating conditions.

Abstract: A method of operating a gas turbine engine is provided. The method includes: providing a flow of a primary fuel to a combustor of a turbomachine, the turbomachine including a compressor, a turbine, and a spool rotatable with the compressor and the turbine; receiving data indicative of a spool parameter of the spool; and modifying a flow of a secondary fuel to the combustor in response to the received data indicative of the spool parameter of the spool.

Abstract: A propulsion system for an aircraft, the aircraft including an aircraft fuel supply, the propulsion system including: a turbomachine including a compressor section, a combustion section, and a turbine section arranged in serial flow order, the combustion section configured to receive a flow of aviation fuel from the aircraft fuel supply; and a fuel cell assembly including a fuel cell stack having a solid oxide fuel cell, the solid oxide fuel cell defining an outlet positioned to remove output products from the solid oxide fuel cell and provide the output products to the combustion section, the solid oxide fuel cell including a cathode; an electrolyte layer; and an anode positioned opposite the electrolyte layer from the cathode, the anode including a cermet, the cermet including less than 25% by volume nickel.

Abstract: A propulsion system is provided including: a gas turbine engine including a combustion section having a combustor; and a modular fuel cell assembly. The modular fuel cell assembly includes: a first fuel cell string comprising a first processing unit and a first fuel cell stack, the first fuel cell stack comprising a first fuel cell defining an outlet configured to provide output products from the first fuel cell to the combustor; and a second fuel cell string comprising a second processing unit and a second fuel cell stack, the second fuel cell stack comprising a second fuel cell defining an outlet configured to provide output products from the second fuel cell to the combustor.

Abstract: An anti-stall system for an aircraft may be provided, where the aircraft includes a propulsion system including a fuel cell assembly and a combustion engine, the combustion engine including a compressor section having a compressor. The anti-stall system may include at least one sensor configured to sense data indicative of at least one operating parameter indicative of a compressor stall condition of the compressor; and a controller including a processor and a memory storing instructions that when executed by the processor cause the controller to determine that the at least one operating parameter has achieved a compressor stall condition threshold and execute an anti-stall action responsive to determining that the at least one operating parameter has achieved the compression stall condition threshold. The anti-stall action may be configured to adjust at least one fuel cell parameter.

Abstract: A method is provided for operating a propulsion system having a gas turbine engine and a fuel cell assembly. The fuel cell assembly includes a fuel cell. The method includes: receiving gas composition data of output products from the fuel cell; and controlling operation of the fuel cell assembly, the gas turbine engine, or both in response to the received gas composition data of the output products from the fuel cell.

Abstract: A propulsion system is provided including: a propulsor; a turbomachine operable to drive the propulsor to generate thrust during operation; a fuel cell assembly configured to add power to the propulsor, the turbomachine, or both; and a multi-gas sensor operable with the turbomachine, the fuel cell assembly, or both for sensing gas composition data of a fluid flow in or to the turbomachine, the fuel cell assembly, or both, the gas composition data comprising data indicative of at least two gases and their concentrations.