A computer-implemented method. The method comprising: (a) obtaining a candidate characterising code, the candidate characterising code being indicative of character of an example of a physical system; (b) accessing a database of extant characterising codes, the extant characterising codes being indicative of character of other examples of the physical system; (c) determining a degree of similarity between the candidate characterising code, and at least one of the extant characterising code; and (e) providing, as an output, the results of the comparison.

The present invention concerns a method for monitoring an actuating system of a movable component, in particular a movable component of a turbomachine such as a nozzle or a blade, the actuating system comprising a control device configured to deliver a position instruction to a first cylinder and a second cylinder, each cylinder being configured to deliver a position feedback measurement in response to the position instruction, the method being implemented in a monitoring system and comprising, —a first monitoring mode in which the deviations between the position feedback measurements of the two cylinders are detected; —a second monitoring mode in which the deviations between the position feedback measurements of the two cylinders are not detected; method in which the second mode is selected when at least one of the two position feedback measurements is in a transient phase.

A bleed air cooling system for a gas turbine engine includes one or more bleed ports located at one or more axial locations of the gas turbine engine to divert a bleed airflow from a gas turbine engine flowpath, a bleed outlet located at a cooling location of the gas turbine engine and a bleed duct in fluid communication with the bleed port and the configured to convey the bleed airflow from the bleed port to the bleed outlet. One or more safety sensors are configured to sense operational characteristics of the gas turbine engine, and a controller is operably connected to the one or more safety sensors and configured to evaluate the sensed operational characteristics for anomalies in operation of the bleed air cooling system.

There are describes methods and systems for operating an engine coupled to a fuel system having a fuel manifold configured to supply fuel to a combustor of the engine. The method comprises receiving a gaseous fuel flow request indicative of a change in demand for gaseous fuel to the engine; applying a fuel loss bias to the gaseous fuel flow request to obtain a biased fuel flow request, the fuel loss bias associated with a change in mass flow rate of the gaseous fuel from the fuel manifold to the combustor in response to the change in demand; and causing the gaseous fuel to flow into the combustor in accordance with the biased fuel flow request.

A scramjet engine has a first passage forming member and a second passage forming member. A passage is formed between a first surface and a second surface. The passage has an upstream zone, a combustion zone and a downstream zone. A cavity of a concave shape is provided on the first surface in the combustion zone. The first passage forming member has a convex section located in the upstream zone, a first fuel injection section configured to inject fuel into the passage from a first fuel nozzle provided for the convex section, and a second fuel injection section configured to inject fuel to the cavity. The second passage forming member has a third fuel injection section configured to inject fuel to a direction toward the first surface from the second surface in the passage through a second fuel nozzle provided in the downstream zone.

A method of refuelling an aircraft comprising a gas turbine engine and a fuel tank arranged to provide fuel to the gas turbine engine comprises obtaining an amount of energy required for an intended flight profile; obtaining a calorific value of fuel available to the aircraft for refuelling; calculating the amount of the available fuel needed to provide the required energy; and refuelling the aircraft with the calculated amount of the available fuel. The calculating the amount of the available fuel needed to provide the required energy may comprise obtaining an energy content of fuel already in the fuel tank and subtracting that from the determined amount of energy required for the intended flight profile.

A method of controlling a complex system and a gas turbine being controlled by the method are provided. The method comprises providing training data, which training data represents at least a portion of a state space of the system; setting a generic control objective for the system and a corresponding set point; and exploring the state space, using Reinforcement Learning, for a control policy for the system which maximizes an expected total reward. The expected total reward depends on a randomized deviation of the generic control objective from the corresponding set point.

Systems and methods to control gas turbine firing temperatures during air injection. A method of achieving a desired firing temperature of a gas turbine engine during air injection comprises injecting compressed air into the gas turbine engine using an external source. The external source includes a compressor and a recuperator. The method comprises using a controller of the gas turbine engine to: (a) determine an air injection exhaust bias gain using an inlet temperature of the gas turbine engine; (b) calculate, based on the determined air injection exhaust bias gain and a flow rate of the injected compressed air, an air injection exhaust curve bias; and (c) change a fuel flow of the gas turbine engine by adding the air injection exhaust curve bias to an existing exhaust curve of the gas turbine engine to thereby achieve the desired firing temperature during air injection.

A control system of a gas turbine engine is provided. The engine has a fuel flow metering valve which regulates a fuel flow to the engine, and one or more variable geometry components which are movable between different set points to vary an operating configuration of the engine. The control system has an engine fuel control sub-system which provides a fuel flow demand signal for controlling the fuel flow metering valve. The control system further has a variable geometry control sub-system which determines current set points to be adopted by the variable geometry components given the current engine operating condition in order to comply with one or more engine constraints. The control system further has an optimiser that receives the current set points and determines adjusted values of the set points which optimise, while complying with the engine constraints, an objective function modelling a performance characteristic of the engine, the objective function adapting to change in engine performance with time. The control system further has a feedback loop in which the adjusted values of the set points thus-determined are sent to the variable geometry control sub-system to vary the current set points.

The present invention concerns a method for monitoring an actuating system of a movable component, in particular a movable component of a turbomachine such as a nozzle or a blade, the actuating system comprising a control device configured to deliver a position instruction to a first cylinder and a second cylinder, each cylinder being configured to deliver a position feedback measurement in response to the position instruction, the method being implemented in a monitoring system and comprising, —a first monitoring mode in which the deviations between the position feedback measurements of the two cylinders are detected; —a second monitoring mode in which the deviations between the position feedback measurements of the two cylinders are not detected; method in which the second mode is selected when at least one of the two position feedback measurements is in a transient phase.