Abstract: A combustion chamber comprises an upstream ring structure, a downstream ring structure and a plurality of circumferentially arranged combustion chamber segments. Each combustion chamber segment extends the full length of the combustion chamber. Each combustion chamber segment comprises a frame structure and at least an inner wall and the frame structure and the inner wall are integral. An upstream end of each combustion chamber segment is secured to the upstream ring structure and a downstream end of each combustion chamber segment is mounted on the downstream ring structure. The combustion chamber segments are manufactured by additive layer manufacture. The combustion chamber segments have a stiff frame structure which carries the structural loads, the thermal loads, surge loads and flameout loads and the frame structure distributes loads into adjacent components.

Abstract: A power system includes a synchronous electrical generator having a rotor driven by a shaft; a permanent magnet signaling generator, coupled to the shaft; and an angle computation unit configured to calculate a rotor angle or load angle based on a voltage from the permanent magnet signaling generator and a voltage from the synchronous electrical generator.

Abstract: A method of manufacturing a hollow aerofoil component 100 for a gas turbine engine 10 comprises joining a first panel 200 to a second panel 300 using bonding, and hot forming the panels into shape. The bonding step and the hot forming step are performed in the same rig, thereby optimizing process time and component quality.

Abstract: A method determines a generator system load and/or rotor angle. The generator system has a generator with a generator terminal outputting electrical power generated by the generator, a transformer and a point of common coupling, PCC, terminal. The transformer is between the generator and PCC terminals. The method includes: determining the generator field current; determining the output voltage, the output current and the power factor and/or angle of the output voltage and output current from the generator terminal, and determining the load angle of the generator system, output voltage from the generator terminal, output current from the generator terminal and the power factor and/or angle; and/or determining the output voltage, the output current and the power factor and/or angle of the output voltage and output current, and determining the rotor angle of the generator system, output voltage, output current from the PCC terminal and the power factor and/or angle.

Abstract: Methods for reducing cracking in metallic components fabricated via additive layer manufacturing (ALM) include a method for additive layer manufacturing of a metallic component, comprising the steps of: providing a powder bed on a substrate; scanning a laser beam across the powder bed to fuse the powder and form a layer of the metallic component; replenishing the powder bed and repeating the step of scanning the laser beam across the powder to form a plurality of successive layers of the metallic component; and heat treating the metallic component to a stress relieving treatment temperature, wherein the metallic component prior to heat treatment has a porosity of between 0.15% and 0.5% and the step of heat treating the metallic component includes heating the metallic component to the stress relieving treatment temperature at a heating rate of greater than 50° C. per minute.

Abstract: A power system, including: a synchronous electrical generator having a rotor; and an angle computation unit configured to: determine a rotor angle in a steady state period of the synchronous electrical generator, determine a change in rotor angle in a transient period of the synchronous electrical generator, and estimate the rotor angle in the transient period based on the steady state rotor angle and the change in rotor angle.

Abstract: An oil recovery system arranged to recover lubricating oil in a gas turbine engine, the oil recovery system comprising: a separator arranged to extract lubricating oil from a mixture of lubricating oil and air; an oil tank arranged to collect lubricating oil extracted from the mixture; and an exit mast arranged to vent air extracted from the mixture overboard from a core of the engine, wherein the exit mast comprises one or more openings for venting air from the separator; and wherein the one or more openings faces at least partially upstream relative to a direction of airflow through the gas turbine engine, such that the air is vented in the upstream direction, and a dynamic head of any airflow pressurises the oil tank, via the exit mast.

Abstract: An aircraft cabin blower system is described having a hydraulic circuit comprising a first hydraulic device and a second hydraulic device. The first hydraulic device is mechanically coupled to a cabin blower compressor and the second hydraulic device is arranged in use to be mechanically coupled to a spool of a gas turbine engine. The first hydraulic device is capable of performing as a hydraulic motor and the second hydraulic device is capable of performing as a hydraulic pump. When, in use, the system is operating in a cabin blower configuration, a driving force supplied by the spool of the gas turbine causes the second hydraulic device to pump liquid provided in the hydraulic circuit and thereby to drive the first hydraulic device, which in turn rotates the cabin blower compressor.

Abstract: A method of controlling a working gap between one or more cathodic tools and an anodic workpiece in an electrochemical material dissolution process, the method comprising: providing a cathodic tool and an anodic workpiece defining a working gap therebetween, the cathodic tool and the workpiece being at least partially immersed in a conductive electrolyte solution; providing a negative electrical potential to the cathodic tool; monitoring one or more of the electrical potential, current, current density and charge between the cathodic tool and the anode to determine the working gap between the cathodic tool and the anode; and, controlling one or more process parameters to maintain one or more of the working gap and electrochemical working conditions between the cathodic tool and anodic workpiece at a targeted value.

Abstract: A compressor stage of a gas turbine engine is provided. The compressor stage has a circumferential row of static vanes and a radially outer casing. Each vane has a radially outer and forwardly projecting front tenon which on build of the compressor stage is received into a first recess of the casing. Each vane also has a radially outer and rearwardly projecting rear tenon which on build of the compressor stage is received into a second recess of the casing. Each vane further has a baulking tab adjacent one of the front and the rear tenons. The casing has a respective baulking land adjacent the recess into which the other of the front and the rear tenons is received. The baulking tab and the baulking land are configured such that if the vane is attempted to be installed in the stage back-to-front, the baulking tab interferes with the baulking land to prevent completion of the build of the compressor stage.

Abstract: A blade track for a gas turbine engine includes segments and joints that couple the segments together. Each segment extends part-way around a central axis of the engine and the joints couple together adjacent segments to form a full hoop.

Abstract: A cooled gas turbine engine component comprises a wall which has a plurality of effusion cooling apertures extending there-through from a first surface to a second surface. Each aperture has an inlet in the first surface and an outlet in the second surface. Each aperture has a metering portion and a diffusing portion arranged in flow series and each metering portion is elongate and the width is greater than the length of the metering portion. The metering portion of each aperture has a U-shaped bend. The diffusing portion of each aperture is arranged at an angle to the second surface. Each outlet has a rectangular shape in the second surface of the wall. Each inlet has an elongate shape in the first surface of the wall and the inlet in the wall is arranged substantially diagonally with respect to the outlet in the wall.

Abstract: A computer-based method of simulating rotor-stator unsteady turbulent flow interaction in turbomachinery, which includes performing CFD ensemble-averaged flow field simulation over the coarse mesh and performing CFD large eddy simulations over the fine meshes, the ensemble-averaged and large eddy simulations being coupled to each other, and the large eddy simulations of the regions of the selected blade passages being used to derive unsteady turbulence stress terms in the ensemble-averaged simulation for corresponding regions of the blade passages of the first and second rows without fine meshes.

Abstract: A vortex detection method is described. The method comprises storing a plurality of points at locations over a region (32) in which vortex detection is to be performed. A value for each of a plurality of fluid flow parameters, such as velocity, pressure and density, is determined at each point. The points are grouped as being contained in either a vortical flow portion or non-vortical flow portion of the region according to one or more statistical distribution for said fluid flow parameters. A point (p) in a vortex core is identified according to the direction of motion of an array of further points (46) relative to said point in the vortex core. The further points (46) may surround the vortex core point.

Abstract: A multistage compressor for a gas turbine engine is disclosed. The compressor includes a plurality of compressor stages, each stage including in axial flow series a row of rotor blades and a row of stator vanes; a hub to which a radially inner end of each rotor blade of the rows of rotor blades is connected; and a casing that circumscribes the rows of rotor blades and the rows of stator vanes. An aerofoil portion of each of the rotor blades and/or the stator vanes of one or more of the plurality of compressor stages is profiled in a spanwise direction such that the aerofoil portion has a trailing edge that is angled more towards an axial direction of the multistage compressor in regions of the aerofoil portion proximal to the casing and the hub than in a mid-region of the aerofoil portion.

Abstract: There is provided an air intake system for providing air to a tip clearance control system. The air intake system comprises a ram-air intake having a scoop portion and a body portion. The body portion of the ram-air intake houses a heat exchanger.

Abstract: An aircraft environmental control system (20) comprises a first heat exchanger (24) configured to exchange heat between air provided by a pressurised air source (13) and a working fluid of a closed cycle refrigeration system, and an air turbine (32) configured to receive cooled air from the first heat exchanger (24). The closed cycle refrigeration system comprises a closed cycle refrigeration system compressor (35) driven by the air turbine (32), a closed cycle refrigeration system expander (36), and a second heat exchanger (33) configured to exchange heat between working fluid of the closed cycle refrigeration system and air downstream of the air turbine (32). The air turbine drives a further load (39).

Abstract: A system for mounting a gas turbine engine to a pylon on a wing of an aircraft. A temporary forward link, being length-adjustable, and at least one temporary rearward link, being length-adjustable, are provided. These are for temporarily attaching the gas turbine engine to the pylon. The temporary forward link and the temporary rearward link are each adapted to resist tension and compression, to maintain a positional relationship between the gas turbine engine and the pylon in the absence of adjustment of the lengths of the temporary forward link and the temporary rearward link. Adjustment of the length of the temporary links brings engine mounts into alignment with pylon mounts for service attachment of the gas turbine engine to the pylon.

Abstract: A nickel-base superalloy includes essentially, by weight: 14.75 to 26.5 percent cobalt, 4.1 to 4.65 percent aluminium, 1.1 to 1.9 percent titanium, 3.85 to 6.3 percent tantalum, 1.2 to 2.55 percent niobium, up to 0.07 percent boron, up to 0.06 percent carbon, up to 14.0 percent chromium, up to 1.0 percent iron, up to 1.0 percent manganese, up to 4.2 percent molybdenum, up to 0.5 percent silicon, up to 4.9 percent tungsten, and up to 0.1 percent zirconium, the balance being nickel and incidental impurities; wherein the overall concentration in the alloy of aluminium, titanium, tantalum, and niobium is from 13 to 14 atomic percent and the atomic ratio of aluminium to titanium is from 4.625:1 to 6.333:1.

Abstract: A method for managing ice accretion on a gas turbine engine component comprises providing an ice management system comprising a de-icing promoter applied to only portions of a gas turbine engine component. The method further comprises operating the ice management system in icing conditions to promote the shedding of ice accreted on the gas turbine engine component on those portions where the de-icing promoter is applied.