Abstract: In order to improve cooling of a blade 31, 41/disc 32, 42 combination, a pre-swirler feature 40, 50 is utilised in order to present coolant air through presentational pathways typically incorporating holes 37 or grooves/slots such that coolant air displaces hotter air leaked past a seal 35, 45. The swirler features 40, 50 are located within stationary housing components 34, 44 such that the coolant air is propelled at substantially the same rotational speed as the disc 32, 42 whilst presentation of the coolant air flow A, C, E is such that hot air displacement is achieved at least adjacent front faces 36, 46 of blade roots 33, 43.

Abstract: A phosphate bonded ceramic is used to provide a diffusion barrier on a titanium alloy substrate, conferring degradation (eg oxidation) resistance to the alloy. The substrate may, for example, be an aerospace component such as a part of a gas turbine engine.

Abstract: A fuel injector for a gas turbine engine has a swirl slot that supplies fuel to a prefilmer. The swirl slot has an upstream lip and a downstream lip that are arranged eccentrically. The slot is thus provided with an area of high static pressure and an area of low static pressure caused by the flowing over the eccentrically arranged lips.

Abstract: A single crystal component comprising a first region and a second region. The component comprising a nickel base single crystal superalloy having a gamma phase matrix and gamma prime phase precipitates distributed in the gamma phase matrix. The first region of the component comprises a bi-modal distribution of gamma prime phase precipitates in the gamma phase matrix and the second region of the component comprising a uni-modal distribution of gamma prime phase precipitates in the gamma phase matrix.

Abstract: Cooling arrangements have been provided for blades and in particular turbine blades utilising gas turbine engines. Generally for internal strength a leading passage has been separate by a solid wall from a feed passage as impingement apertures may diminish structural strength as centres for stress concentration. However, impingement apertures allow impingement jets which have improved cooling efficiency. By providing a leading passage which is divided at least into a lower section and an upper section the lower section can have a wall which is solid for structural integrity whilst an upper section has impingement apertures for greater cooling efficiency.

Abstract: A gas turbine engine (10) comprising a compressor (14), a turbine (16) a combustor (20) and a recuperator (26), a first portion air (22) from the compressor (20) is ducted into the combustor (20) where it mixes with fuel and is burned, a second portion (24) of compressor air passes through a high-pressure side of the recuperator (26) where it is heated by gas (32) ducted from the turbine (16), the second portion of air (24) flowing through the recuperator (26) is mixed with the first portion of gas (22) to form a third gas flow (30) which is ducted into the turbine (16).

Abstract: Electrical machine arrangements have advantages with regard to providing local electrical power and starting. Embedding such electrical machine arrangements in machinery such as gas turbine engines is advantageous in removing mechanical linkages and reducing aerodynamic drag. However, the components utilised must be able to withstand harsh environmental conditions and therefore the DC link capacitor used for smoothing of voltage fluctuations are limited to relatively low capacitance densities. Low density DC link capacitors require large sizes which render electrical machines less acceptable for embedded usage. By providing offset of electrical current in inductance elements such as stator windings and stator coils of electrical machines in dead periods of the cycle a reduction in DC link capacitor requirements is achieved reducing the size, weight and complexity of installing electrical machines in gas turbine engines.

Abstract: A method for measuring the gap between a multibladed rotatable member and a surrounding housing in a gas turbine engine. In accordance with the method, a blade is removed from the rotatable member and replaced by a distance measuring clearance probe. The distance from the probe to the housing is then measured at a number of axial positions of the rotatable member.

Abstract: A method of operating a contra-rotating propeller engine that preferably comprises a 12 bladed front and a 9 bladed rear propeller. As is conventional, the engine is operated during at least a take-off phase, a cruise phase and an approach phase; during the cruise phase the engine operates with a generally constant propeller tip speed. The method is characterised by the step of operating the engine such that the tip speed of either or both of the propellers, during at least one of take-off, climb or approach, at least 10% greater than cruise tip speed. With a specific front to rear propeller spacing, increasing the tip speed reduces overall noise generated by the propellers.

Abstract: An arrangement for controlling flow of fluid to at least one component of a gas turbine engine, the arrangement comprising: a first conduit for providing fluid to the component; a flow valve, for controlling the flow of fluid in the first conduit, having first and second configurations; a second conduit for providing fluid to the flow valve to the control the configuration of the flow valve; and a magnetic valve, for controlling the flow of fluid in the second conduit, having first and second configurations and including at least one ferromagnet forming a portion of a magnetic circuit, whereby the configuration of the magnetic valve depends on the temperature of the ferromagnet; the member comprising ferromagnetic material (68) is thermally coupled to one of the group comprising the fluid in the first conduit (24), the fluid in the second conduit (54) and the component; and the configuration of the flow valve is dependent on the configuration of the magnetic valve.

Abstract: An aircraft comprising a gas turbine engine that exhausts a plume of gases in use, the aircraft comprises an ultrasound generator having an ultrasonic actuator and a waveguide to direct ultrasonic waves at the exhaust plume to avoid the formation of contrails.

Abstract: A method of manufacturing a thin wall isogrid or the like casing by a machining process comprising the steps of: mating a surface of a casing precursor (10,50) with a substantially continuous support surface (20,60) of a hollow support sleeve (18, 58); engaging an engagement surface (26, 66) of a deformation member (24, 64) with an engagement surface (22,62) of the support sleeve (18,58), the engagement surface (22, 62) of the support sleeve (18,58) being opposite the support surface (20,60) and the deformation member (24,64) being co-axially arranged with the support sleeve (18,58); axially displacing the support sleeve (18,58) and deformation member (24,64) relative to one another, the deformation member (24,64) engagement surface (22,62) and support sleeve (18,58) engagement surface (22,62) being configured such that the support sleeve (18,58) is deformed by the deformation member (24,64) by the relative axial displacement in order to mate the support surface (20,60) with substantially the whole of the sur

Abstract: A repaired composite material component 24 comprises parent composite material 12, a primary region 14 of replacement composite material and a secondary region 26 of replacement composite material which has a greater tendency to debond under loading of the repaired composite material component 24 than the primary region 14.

Abstract: Problems can arise with regard to noise created by bleed valve arrangements (5, 25, 50, 70) in gas turbine engines (10). It is known to utilise pressure differential inducing elements (29, 59, 55) such as pepper pots and perforated surfaces in order to attenuate noise from bleed valves. However, these arrangements tend to have a portion which expands such that the exit aperture (27, 54) into a bypass duct wall (53) can significantly affect mechanical strength and operational performance. By providing internally created pepper pots (29, 59) or other pressure differential inducing elements within a path of an arrangement (25, 50, 70) and a constriction to an exit (27, 54) noise attenuation is still achieved but with less detrimental effect with regard to bypass duct wall strength and aerodynamic losses altering operational performance.

Abstract: There is provided a method comprising the steps of determining an environmental impact of a product by: identifying one or more processes performed during the life cycle of the product; selecting identifying at least one design parameter relating to a the product and being associated with the identified process or processes; representing each of the identified processes by a process model, the process model identifying interventions by the process on the environment; and quantifying the interventions of each process on the environment using the at least one design parameter; and determining at least one environmental impact of the product from the design parameter or parameters; and generating an output indicating the environmental impact of the product.

Abstract: A thermocouple connector has a first member and a second member which couples to the first member. The first member carries two first terminals for electrically joining to the respective ends of a pair of thermocouple wires. The second member carries two corresponding second terminals for electrically joining to the respective ends of a pair of thermocouple extension wires. Each first terminal contacts a respective second terminal when the first and second members are coupled.

Abstract: An aerofoil comprising a pressure-side wall, a suction-side wall and an intermediate wall extending from a free end of the pressure-side wall at an acute angle relative thereto towards the suction-side wall. A cooling fluid passageway extends through a region where the intermediate wall meets the pressure-side wall at an apex. The fluid passageway has an opening, at least in part, in the face of the pressure-side wall.

Abstract: A method for detecting overpressure inside a compartment associated with a gas turbine nacelle, the method comprising: a) measuring one or more predetermined operating conditions nominally affecting the temperature inside the compartment; b) determining a reference temperature for the compartment, corresponding to a nominal reference zone pressure, on the basis of the measured operating condition or conditions; c) measuring the actual temperature inside the compartment, corresponding to the actual compartment pressure; and d) using the measured actual temperature in the compartment and the determined reference temperature for the compartment to assess the gas pressure inside the compartment. In one embodiment, there is disclosed a system for assessing the gas pressure inside the compartment caused by an associated pressure system failure, comprising using a quantified mass leakage flow to assess gas pressure inside the compartment.

Abstract: A gas turbine engine turbine comprises an annular array of nozzle guide vanes and an annular array of turbine blades mounted within its annular casing. An array of radially extending protrusions are positioned axially upstream of said array of said nozzle guide vanes and protruding inwardly from the inner casing wall so as to mix the tangential momentum component of the overtip leakage fluid flow before it reaches the array of nozzle guide vanes.

Abstract: A wall cooling arrangement comprising on one side of a wall a multiplicity of cooling fluid inlet apertures and on the opposite of the wall a multiplicity of cooling fluid exit apertures, and in the body of the wall linking said inlet and exit apertures a network of multiply branched cooling passages. Flow of cooling fluid through a network is controlled by a throat positioned either at or close to the inlet to the passage network or at a location part way through the network, in which case there may be a plurality of inlet apertures feeding through a single throat to a plurality of outlet apertures.