Abstract: A propulsion system includes at least two propulsors. The at least two propulsors each comprising a fan having a plurality of fan blades. A controller includes memory and one or more processors. The memory stores instructions that when executed by the one or more processors cause the system to perform the following: determine a pairwise phase difference between one propulsor of the at least two propulsors and another propulsor of the at least two propulsors; generate a reference phase angle; determine a target phase shift for each propulsor of the at least two propulsors; and adjust a speed of each propulsor of the at least two propulsors based on the target phase shift until the pairwise phase difference is equal to the reference phase angle.

Abstract: A propulsion system includes at least two propulsors. The at least two propulsors each include a fan and a controller having one or more processors configured to implement controller logic. The controller logic includes a phase angle control scheme and a speed control scheme. In implementing the controller logic, the one or more processors are configured to: determine an actual pairwise phase difference between a pair of propulsors of the at least two propulsors; generate a reference phase angle for the pair of propulsors; compare the actual pairwise phase difference to the reference phase angle to generate a phase error; provide the phase error to a phase controller module to generate an output based on the phase error; and adjust a speed of at least one propulsor of the at least two propulsors based on the output to drive the phase error towards zero.

Abstract: A propulsion system is provided, the propulsion system including a variable pitch rotor assembly including a plurality of blades coupled to a disk. The plurality of blades includes a first blade configured to articulate a first blade pitch separately from a second blade configured to articulate a second blade pitch. A vane assembly is positioned in aerodynamic relationship with the variable pitch rotor assembly. A core engine including a high speed spool and a low speed spool, wherein the low speed spool is operably coupled to the rotor assembly. One or more controllers is configured to execute operations. The operations include articulating the first blade of the rotor assembly, wherein articulating the first blade alters the first blade pitch, and articulating the second blade of the rotor assembly, wherein articulating the second blade alters the second blade pitch.

Abstract: A gas turbine engine fuel supply system can include a fuel delivery system, a thermal management system, a fuel manifold, and one or more sensors that identify one or more fuel parameters. A fuel control system adjusts parameters of the fuel based on data received from the sensors.

Abstract: A method is provided for operating a hybrid-electric propulsion system having a first engine, a second engine, a first electric machine coupled to the first engine, and a second electric machine coupled to one of the first engine or the second engine. The method includes: receiving data indicative of a first engine operating parameter, a second engine operating parameter, or both; determining a first engine operating parameter margin, a second parameter operating margin, or both; determining a load share for the first engine, the second engine, or both, or between the first engine and the second engine based on the first engine operating parameter margin, the second engine operating parameter margin, or both; and transferring a first amount of power to or from the first electric machine and a second amount of power to or from the second electric machine in response to the determined load share.

Abstract: Systems and methods for high bandwidth control of thrust response for turbofan or turboprop engines are provided. Such systems and methods include an engine control system that processes a rate command and a feedback signal from an engine to generate separate fuel and electric machine control signals that respectively control fuel and electric machine dynamics of the engine to produce engine dynamics that result in desired thrust response.

Abstract: A method of transient control of a thermal transport bus of a turbomachine includes measuring a measured temperature and a measured pressure of a working fluid; determining a selected run state of a turbomachine, wherein the selected run state is one of a plurality of run states; selecting a desired operating condition comprising a desired temperature range and a desired pressure range as a function of a desired state of the working fluid; comparing the measured temperature with the desired temperature range, and comparing the measured pressure with the desired pressure range; and modulating control of the thermal transport bus as a function of the comparing of the measured temperature with the desired temperature range and the comparing of the measured pressure with the desired pressure range.

Abstract: A method is provided for operating a hybrid-electric propulsion system having a first engine, a second engine, a first electric machine coupled to the first engine, and a second electric machine coupled to one of the first engine or the second engine. The method includes: receiving data indicative of a first engine operating parameter, a second engine operating parameter, or both; determining a first engine operating parameter margin, a second parameter operating margin, or both; determining a load share for the first engine, the second engine, or both, or between the first engine and the second engine based on the first engine operating parameter margin, the second engine operating parameter margin, or both; and transferring a first amount of power to or from the first electric machine and a second amount of power to or from the second electric machine in response to the determined load share.

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: Systems and methods for high bandwidth control of thrust response for turbofan or turboprop engines are provided. Such systems and methods include an engine control system that processes a rate command and a feedback signal from an engine to generate separate fuel and electric machine control signals that respectively control fuel and electric machine dynamics of the engine to produce engine dynamics that result in desired thrust response.

Abstract: A method of transient control of a thermal transport bus of a turbomachine includes measuring a measured temperature and a measured pressure of a working fluid; determining a selected run state of a turbomachine, wherein the selected run state is one of a plurality of run states; selecting a desired operating condition comprising a desired temperature range and a desired pressure range as a function of a desired state of the working fluid; comparing the measured temperature with the desired temperature range, and comparing the measured pressure with the desired pressure range; and modulating control of the thermal transport bus as a function of the comparing of the measured temperature with the desired temperature range and the comparing of the measured pressure with the desired pressure range.

Abstract: Systems and methods for high bandwidth control of thrust response for turbofan or turboprop engines are provided. Such systems and methods include an engine control system that processes a rate command and a feedback signal from an engine to generate separate fuel and electric machine control signals that respectively control fuel and electric machine dynamics of the engine to produce engine dynamics that result in desired thrust response.

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: An open rotor engine includes a core engine, a plurality of guide vanes positioned within or extending from the core engine; and a pitch change assembly operably coupled to the plurality of guide vanes. The pitch change assembly includes one or more actuators configured to change a pitch angle of respective ones of the plurality of guide vanes, and a plurality of linkage arms that are respectively movable by actuation of at least one of the one or more actuators. The plurality of linkage arms are directly or indirectly coupled to a corresponding one of the plurality of guide vanes. The plurality of linkage arms may have a length that differs from one another, and such length may orient a displacement or a range of motion of the respective linkage arm to an envelope of rotation about a guide vane axis that differs as between the plurality of guide vanes.

Abstract: An open rotor aeronautical engine may include a core engine, a plurality of unducted airfoils, and a pitch change assembly. The pitch change assembly may include an ensemble actuator assembly and a unitary actuator assembly. The ensemble actuator assembly may have one or more ensemble actuators and a unison ring that is movable by actuation of the one or more ensemble actuators to collectively change a pitch angle of the plurality of unducted airfoils. The unitary actuator assembly comprising a plurality of unitary actuators respectively coupled to a corresponding one of the plurality of unducted airfoils, the plurality of unitary actuators respectively movable to change the pitch angle of the corresponding one of the plurality of unducted airfoils.

Abstract: A method of controlling an aeronautical gas turbine engine may be performed with an electronic controller. The method may include determining an airfoil pitch control command for at least one of a plurality of airfoils of the aeronautical gas turbine engine based at least in part on an excitation load acting upon the aeronautical gas turbine engine, and outputting the airfoil pitch control command to one or more actuators actuatable to change a pitch angle of the at least one of the plurality of airfoils. The airfoil pitch control command may be configured to augment and/or compensate for the excitation load acting upon the aeronautical gas turbine engine. The method may be embodied by a non-transitory computer-readable medium that includes computer-executable instructions, which when executed by a processor associated with the electronic controller, cause the electronic controller to perform the method.

Abstract: A gas turbine engine fuel supply system can include a fuel delivery system, a thermal management system, a fuel manifold, and one or more sensors that identify one or more fuel parameters. A fuel control system can be controlled to adjust one or more parameters of the fuel based on data received from the sensors.

Abstract: A control system for active stability management of a compressor element of a turbine engine is provided. In one example aspect, the control system includes one or more computing devices configured to receive data indicative of an operating characteristic associated with the compressor element. For instance, the data can be received from a high frequency sensor operable to sense pressure at the compressor element. The computing devices are also configured to determine, by a machine-learned model, a stall margin remaining of the compressor element based at least in part on the received data. The machine-learned model is trained to recognize certain characteristics of the received data and associate the characteristics with a stall margin remaining of the compressor element. The computing devices are also configured to cause adjustment of one or more engine systems based at least in part on the determined stall margin remaining.

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 computing system for an unducted rotor engine with a variable pitch vane assembly in aerodynamic relationship with an unducted rotor assembly, including a sensor-based controller configured to execute a first set of operations and a model-based controller configured to execute a second set of operations. The first set of operations includes obtaining a first signal corresponding to a commanded low spool speed; obtaining a second signal indicative of a pitch angle corresponding to thrust output from the unducted rotor assembly and variable pitch vane assembly; generating a pitch feedback signal corresponding to a commanded adjustment to the pitch angle based at least on one or both of a variable blade pitch angle or a variable vane pitch angle. The second set of operations include obtaining a desired thrust output via a throttle input; determining, at least via a power management block, a commanded thrust output signal; receiving the commanded thrust output signal; and generating an output signal.