An engine system comprises first and second electrical generators coupled to lower and higher pressure (LP, HP) shafts respectively of a gas turbine engine. A controller is arranged to receive a signal corresponding to a total electrical power demand P.sub.1 and to output control signals to the electrical generators in response thereto such that the first and second electrical generators output electrical powers (1−y)P.sub.1 and yP.sub.1 respectively when P.sub.1≤P.sub.m1, where 0.5<y≤1 and P.sub.m1 is the maximum electrical output power of the first electrical generator. By satisfying the demand P.sub.1 mostly by extraction of electrical power from the first electrical generator when possible, the additional mechanical stress on the gas turbine engine resulting from electrical power extraction is reduced compared to the case where 50% or more of the demand P.sub.1 is satisfied by the second electrical generator.

A fuel delivery system includes a turbine, a pump, and an oxygen removal unit. The turbine is adapted to receive and expel fuel at different pressures. The pump is in fluid communication with, and mechanically coupled to, the turbine, and is configured to expel and receive the fuel at about the respective different pressures. The turbine is configured to convert pressure energy of the fuel to kinetic energy to drive the pump. The oxygen removal unit is in fluid communication with at least one of the turbine and the pump, and is configured to remove oxygen from the fuel.

A method can include perturbing an electric motor of a hybrid powerplant having the electric motor and a fuel powered engine. The method can include measuring a frequency response of the powerplant due to the perturbing of the electric motor to determine a health of the powerplant and/or one or more components thereof.

An engine parameter estimation tuning system includes an engine parameter estimator unit and a gas path analysis (GPA) unit. The engine parameter estimator unit includes an onboard model (OBM) configured to output estimated parameters based on operation of a gas turbine engine. The gas path analysis (GPA) unit includes a performance health monitor unit configured to adjust a long-term deterioration parameter independently from adjustment of a short-term tuning parameter to tune one or more targeted estimation parameters included in the estimated engine parameter. In this manner, the engine parameter estimation tuning system can realize the different time scales associated with uncertainties in an engine and accommodate them separately so that the estimated engine parameters become much more accurate.

Control systems and methods for controlling an engine. The control system includes a computation module and an input/output (I/O) module attached to the engine. The computation module is located in an area of the engine, or off-engine, that provides a more benign environment than the environment that the I/O module is subject to during operation of the engine. The I/O module includes a first processor and a first network interface device. The computation module includes a second processor with higher processing power than the first processor, and a second network interface device. The control system also includes a sensor configured to provide sensor readings to the first processor. The first processor transmits data based on the sensor readings to the second processor. The control system also includes an actuator operably coupled to the I/O module and that is controlled by the first processor based on commands from the second processor.

Systems, program products, and methods for adjusting operating limit (OL) thresholds for compressors of gas turbine systems based on mass flow loss are disclosed herein. The systems may include at least one computing device in communication with the gas turbine system, sensor(s) measuring operational characteristic(s) of the gas turbine system, and a pressure sensor measuring an ambient fluid pressure surrounding the gas turbine system. The computing device(s) may be configured to adjust operational parameters of the gas turbine system by performing processes including determining a mass flow loss between an estimated, first mass flow rate and a calculated, second mass flow rate for the compressor of the gas turbine system, and adjusting an OL threshold for the compressor of the gas turbine system based on the mass flow loss. The OL threshold for the compressor may be below a predetermined surge threshold for the compressor.

A system for keep out zone control includes a gas turbine engine and a controller operable to determine a closing threshold with respect to an upper limit and an opening threshold with respect to a lower limit of a movement range of an effector of the gas turbine engine based on an on-board model, where the upper limit and the lower limit define a keep out zone of a target parameter of the gas turbine engine. The controller determines a projected state of the target parameter absent a correction command to the effector, applies a closing correction to the effector based on determining that the projected state of the target parameter would result in being above the closing threshold, and applies an opening correction to the effector based on determining that the projected state of the target parameter would result in being below the opening threshold.

The method can include, in sequence: varying the flow rate of fuel from the first flow rate to a second flow rate, thereby varying the rotor speed from a first speed to a second speed, varying the flow rate of fuel back to the first flow rate, and rotating the rotor at the first speed for a given period of time.

A gas turbine engine component (50, 100, 150, 160, 174, 206, 236), including: a surface (54) subject to loss caused by a wear instrument during operation of the component in a gas turbine engine and a performance feature (80, 82, 102, 152, 162, 172, 200, 230) associated with the surface. The surface and the performance feature interact in a manner that changes with the loss such that a change in performance of the gas turbine engine resulting from the loss is mitigated.

The invention concerns a method for controlling a control valve (20) of a turbomachine operating at an engine speed at a cruise value (Vc) and oscillating around the cruise value (Vc) of same, the method being implemented by a calculation unit (40), and being characterised in that it comprises a step of determining a position control for the control valve (20), filtered of the oscillations of the engine speed around the cruise value (Vc).