Abstract: A fuel flow control system is configured to perform a method including: setting a fuel flow demand proportional to compressor discharge pressure; detecting an actual fuel flow; and applying an enhanced schedule for fuel flow demand while fuel flow demand is less than a predefined proportion of actual fuel flow.

Abstract: A combined cycle heat engine (10). The engine (10) comprises a first gas turbine engine (11) comprising a first air compressor system (14), a first combustion system (16) and a first turbine system (18) and a second gas turbine engine (32) comprising a second air compression system (36), a second turbine system (40), and a heat exchanger (38) configured to transfer heat from an exhaust (24) of the first turbine system (18) to compressed air from the second air compressor (36). The second gas turbine engine (32) comprises a second combustion system (20) downstream of the heat exchanger (38) and upstream of the second turbine system (40).

Abstract: An apparatus measuring thrust of an aircraft gas turbine engine includes a core shaft connecting a turbine and compressor, a fan and gearbox with a sun gear driven by the core shaft, a plurality of planet gears, an annulus gear mounted in a static structure, and a planet carrier driven by the fan via fan shaft. The apparatus includes a sensor to measure force applied by the annulus gear on the static structure and first and second sensors to measure rotational speed of the core and fan shafts. A processor determines restoring torque on the annulus gear from measurement of force applied by the gear on the static structure, torque applied to the fan by the planet carrier using rotational speeds of core and fan shafts and restoring torque on the annulus gear, and thrust of the fan from torque applied to the fan and the fan's rotational speed.

Abstract: A control system for a gas turbine engine includes an engine core, the engine core including combustion equipment, a turbine, a compressor, and a core shaft connecting the turbine to the compressor. The control system includes at least one variable stator vane for controlling the angle at which gas enters the engine core, and there is a bypass passage within the engine core for directing gas flow to bypass the combustion equipment.

Abstract: A fuel flow control system is configured to perform a method including: setting a fuel flow demand proportional to compressor discharge pressure; detecting an actual fuel flow; and applying an enhanced schedule for fuel flow demand while fuel flow demand is less than a predefined proportion of actual fuel flow.

Abstract: A combined cycle heat engine (10). The engine (10) comprises a first gas turbine engine (11) comprising a first air compressor system (14), a first combustion system (16) and a first turbine system (18) and a second gas turbine engine (32) comprising a second air compression system (36), a second turbine system (40), and a heat exchanger (38) configured to transfer heat from an exhaust (24) of the first turbine system (18) to compressed air from the second air compressor (36). The second gas turbine engine (32) comprises a second combustion system (20) downstream of the heat exchanger (38) and upstream of the second turbine system (40).

Abstract: A control system for a gas turbine engine includes an engine core, the engine core including combustion equipment, a turbine, a compressor, and a core shaft connecting the turbine to the compressor. The control system includes at least one variable stator vane for controlling the angle at which gas enters the engine core, and there is a bypass passage within the engine core for directing gas flow to bypass the combustion equipment.

Abstract: A method (30) of controlling fuel flow in a gas turbine engine. First, detect a surge condition. Set fuel flow demand (Wf_D) proportional to compressor discharge pressure (P30). Detect actual fuel flow (Wf_A). Then apply an enhanced schedule (50) for fuel flow demand (Wf_D) while fuel flow demand (Wf_D) is less than a predefined proportion (k) of actual fuel flow (Wf_A). Also a gas turbine engine (10), fuel flow system (68) and fuel flow control system (76) each implementing the method (30).

Abstract: An apparatus measuring thrust of an aircraft gas turbine engine includes a core shaft connecting a turbine and compressor, a fan and gearbox with a sun gear driven by the core shaft, a plurality of planet gears, an annulus gear mounted in a static structure, and a planet carrier driven by the fan via fan shaft. The apparatus includes a sensor to measure force applied by the annulus gear on the static structure and first and second sensors to measure rotational speed of the core and fan shafts. A processor determines restoring torque on the annulus gear from measurement of force applied by the gear on the static structure, torque applied to the fan by the planet carrier using rotational speeds of core and fan shafts and restoring torque on the annulus gear, and thrust of the fan from torque applied to the fan and the fan's rotational speed.

Abstract: A gas turbine engine compressor operating system for a gas turbine engine is disclosed. The gas turbine engine comprises a low pressure compressor and a high pressure compressor. The low and high pressure compressors are driven by low and high pressure shafts respectively, with the high pressure compressor being provided downstream in core mass flow of the low pressure compressor. The compressor operating system comprises a controller configured to control a variable geometry actuator of the low pressure compressor. The controller is configured to control the variable geometry actuator on the basis of low pressure compressor rotational speed (N1) and a high pressure compressor operating parameter such as one or more of core mass flow rate ({dot over (m)}), high pressure compressor pressure ratio (P30:P26), high pressure compressor rotational speed (N2), and high pressure compressor variable guide vane angle (?).

Abstract: A rotor assembly (30) comprising a rotor (32) having an annular array of rotor blades (34), the rotor mounted to a shaft (38). A phonic wheel (40) coupled to the shaft. A speed sensor (44) axially aligned with the phonic wheel and configured to measure voltage (V), amplitude of the voltage being proportional to clearance (46) between the sensor and phonic wheel. A processor (48) configured to: receive the voltage measurement; derive shaft speed (?) from the voltage measurement; identify modulation of the voltage amplitude at a frequency which is an integer multiple of the shaft speed; compare voltage amplitude to a threshold; and output a rotor damage signal based on the comparison.

Abstract: A method for use in a turbine control system includes controlling fuel supply to a gas turbine engine at least in part using a fuel supply limit determined as a first function of a rotational speed of a shaft of the gas turbine engine. The method also includes obtaining a first value representative of a rotational speed of the shaft, and differentiating the first value within a processing unit. The processing unit determines an adjusted fuel supply limit as an adjusted function of the first value. The adjusted function is based on the first function and the differentiated first value. The method further includes controlling the fuel supply to the gas turbine engine at least in part using the adjusted fuel supply limit.

Abstract: A system for operating a gas turbine engine to mitigate the risk of ice formation within the engine, the system including a controller arranged to control at least one operational parameter of the engine such that the engine operates in a safe zone; and, a processor configured to function as a determining module to make a comparison between values and determine whether the engine is operating within a safe zone based on at least a core pressure parameter relating to the pressure within the engine and a core temperature parameter relating to the temperature within the engine, wherein the safe zone is defined by the product (multiplied) of the core pressure parameter and core temperature parameter being above a safe threshold.

Abstract: A rotor assembly (30) comprising a rotor (32) having an annular array of rotor blades (34), the rotor mounted to a shaft (38). A phonic wheel (40) coupled to the shaft. A speed sensor (44) axially aligned with the phonic wheel and configured to measure voltage (V), amplitude of the voltage being proportional to clearance (46) between the sensor and phonic wheel. A processor (48) configured to: receive the voltage measurement; derive shaft speed (?) from the voltage measurement; identify modulation of the voltage amplitude at a frequency which is an integer multiple of the shaft speed; compare voltage amplitude to a threshold; and output a rotor damage signal based on the comparison.

Abstract: A method (30) of controlling fuel flow in a gas turbine engine. First, detect a surge condition. Set fuel flow demand (Wf_D) proportional to compressor discharge pressure (P30). Detect actual fuel flow (Wf_A). Then apply an enhanced schedule (50) for fuel flow demand (Wf_D) while fuel flow demand (Wf_D) is less than a predefined proportion (k) of actual fuel flow (Wf_A). Also a gas turbine engine (10), fuel flow system (68) and fuel flow control system (76) each implementing the method (30).

Abstract: A method for use in a turbine control system includes controlling fuel supply to a gas turbine engine at least in part using a fuel supply limit determined as a first function of a rotational speed of a shaft of the gas turbine engine. The method also includes obtaining a first value representative of a rotational speed of the shaft, and differentiating the first value within a processing unit. The processing unit determines an adjusted fuel supply limit as an adjusted function of the first value. The adjusted function is based on the first function and the differentiated first value. The method further includes controlling the fuel supply to the gas turbine engine at least in part using the adjusted fuel supply limit.

Abstract: A gas turbine engine control system comprising a variable stator vane schedule for normal operation of the gas turbine engine. The system is configured to generate an arm signal indicating potential shaft break. Then the system is configured to alter the variable stator vane schedule to slew each variable stator vane to decrease the available surge margin in response to the arm signal. Or the system is configured to limit a response rate of a variable stator vane actuator in response to the arm signal. Or the system is configured to alter the variable stator vane schedule and limit the response rate of the actuator.

Abstract: A compressor variable stator vane arrangement comprises at least one stage of variable stator vanes. A speed sensor measures the rotational speed of the compressor rotor. A pressure sensor measures the outlet pressure of the compressor. A second pressure sensor, a temperature sensor and a third pressure sensor measure the total inlet pressure, the temperature and the ambient pressure at the inlet of the gas turbine engine. A processor determines a target operating line as a function of ambient pressure and total inlet pressure. The target operating line is defined to ensure the gas turbine engine operates simultaneously at both the minimum required compressor speed and the minimum required compressor outlet pressure when commanded to idle to minimize idle thrust and fuel burn. The processor determines if the operating point of the compressor, defined in terms of corrected outlet pressure and corrected rotational speed of the compressor rotor is above or below the target operating line of the compressor.

Abstract: The present invention relates to control of engine variable of a gas turbine engine to regulate the surge margins of at least two compressors. A controller (20) receives data measured from engine sensors (22, 23) and uses said data to determine an indication of surge margin for each of at least two compressors (6, 7) of the gas turbine engine. The controller (20) uses the indications of surge margin for each of the compressors to determine a control strategy that balances the requirements of each compressor. In one embodiment a surge margin operating map divided into different control domains (40, 43, 43) is used. The indication of surge margin determined for each compressor is plotted to determine which control domains the current operating point on the surge margin operating map falls within.

Abstract: An apparatus and method for inducing waves within a container arranged to permit a through-flow of fluid flowing generally from an inlet of the container to an exit of the container, wherein the container has wave inducing means located at the exit of the container, the wave inducing means being operable to vary the area of the exit thereby inducing waves within the container. The apparatus may form part of a combustor test rig.