Abstract: Where gas turbine engine structure eg combustion equipment, is to be air impingement cooled, the surface which receives the air jets is so shaped as to produce boundary layer separation zones 34, 38 and 44 in the cooling air, as it spreads across the surface. Mixing of the boundary layer with the remainder of the air flow results, followed by the re-establishment of the boundary layer. The new boundary layer is cooler than the original layer and so provides more effective cooling.

Abstract: A method of prestressing a component (30) includes the use of an electrical discharge or current to produce a plasma (39) within a medium (32) located adjacent the component (30). The plasma generates a shock wave which impacts a surface of the component to produce a region of compressive residual stress within the component.

Abstract: An irreversible temperature indicating paint comprise 15 to 18 wt % cobalt ammonium phosphate, 5.0 to 6.0 wt % sodium alumino sulpho silicate, 8.5 to 10.5 wt % silica, 7.0 to 8.5 wt % alumina, 0.5 to 0.7 wt % toluidine red, 35 to 43 wt % acrylic resin and 19 to 23 wt % silicone resin excluding solvent. A particular irreversible temperature indicating paint comprising 16.4 wt % cobalt ammonium phosphate, 5.5 wt % sodium alumino sulpho silicate, 9.4 wt % silica, 7.8 wt % alumina, 0.6 wt % toluidine red, 39.1 wt % acrylic resin and 21.1 wt % silicone resin excluding solvent. The irreversible temperature indicating paint has at least six color changes in the temperature range 550° C. to 1250° C. The irreversible temperature indicating paint is used to determine the temperatures to which various parts of turbine blades, turbine vanes or other components are subjected in operation of a gas turbine engine.

Abstract: An electrical conductor winding (70) comprises a plurality of laminates of electrical insulation (72). Each laminate of electrical insulation (72) has a slot (78) on one surface (76). Each laminate of electrical insulation (70) has an electrical conductor (82) arranged in the slot (78). An electrical connector (84) connects the electrical conductor (82) in one laminate of electrical insulation (78) with the electrical conductor (82) in an adjacent laminate of electrical insulation (72). The laminates of electrical insulation (72) are arranged such that the surface (74) of one laminate of electrical insulation (72) abuts and is bonded to the surface (76) of an adjacent laminate of electrical insulation (12). The laminates of electrical insulation (12) comprise a glass-ceramic material. The electrical conductor windings allow active magnetic bearings, electric motors and electric generators to be used at temperatures up to 500° C. for example in gas turbine engines.

Abstract: A device and method for monitoring variations in the distance between an object and a datum, comprising: a light source, an astigmatic system for projecting an astigmatic image of the light source onto the object, the astigmatic system including the datum; and image shape detector means for detecting changes of shape of the astigmatic image on the object due to the variation in the distance between the object and the datum, and for producing a monitor signal whose value is dependant on the shape of the astigmatic image on the object: the astigmatic system being arranged such that light reflected from the astigmatic image on the object passes back through the astigmatic system and is thereby projected onto a light receiving surface of the image shape detection means as an astigmatic image of the astigmatic image on the object; wherein the astigmatic system comprises a zone plate.

Abstract: An irreversible temperature indicating paint comprises 25 wt % to 50 wt % cobalt silicate, 0 wt % to 20 wt % alumino silicate, 0.5 wt % to 5 wt % toluidine red, 25 wt % to 40 wt % acrylic resin and 10 wt % to 20 wt % silicone resin excluding solvent. The solvent comprises a mixture of 80% 1-methoxy-2-propanol and 20% dipropylene glycol monomethyl ether. The irreversible temperature indicating paint has at least five colour changes in the temperature range 1050° C. to 1350° C. A particular irreversible temperature indicating paint comprises 33.8 wt % cobalt silicate, 16.9 wt % alumino silicate, 2 wt % toluidine red, 30.8 wt % acrylic resin and 16.5 wt % silicone resin excluding solvent. The irreversible temperature indicating paint is used to determine the temperatures to which various parts of turbine blades, turbine vanes or other components are subjected in operation of the gas turbine engine.

Abstract: A gas turbine engine fan blade (26) comprises a root portion (40) and an aerofoil portion (42). The aerofoil portion (42) has a leading edge (44), a trailing edge (46), a concave metal wall portion (50) extending from the leading edge (44) to the trailing edge (46) and a convex metal wall portion (52) extending from the leading edge (44) to the trailing edge (46). The aerofoil portion (42) has a hollow interior (54) and the interior (54) of the aerofoil portion (42) is at least partially filled with a vibration damping material (56). The vibration damping material (56) comprises a material having viscoelasticity for example one formed by mixing an amine terminated polymer and bisphenol a-epichlorohydrin epoxy resin.

Abstract: A wall element (29) for a wall structure (21) of a gas turbine engine combustor (15). The wall element (29) comprises a main member (36) with an upstream edge region (30) and a downstream edge region (31). A plurality of heat removal members (38) are provided on the main member (36). The downstream edge (35) of the wall element and/or the downstream facing surface of the heat removal members closest to the downstream edge (35) are provided with a thermally resistant coating.

Abstract: A gas turbine engine (10) comprises a fan rotor (26) having a plurality of fan blades (24) and an apparatus (34) for detecting damage to the fan blades (24). The apparatus (34) comprises a transducer (36) arranged to detect the pressure in the gas flow around the fan blades (34) and to produce a pressure signal. A speed sensor (48) is arranged to measure the speed of rotation of the fan rotor (26) and to produce a speed signal. A processor unit (40) analyses the pressure signal and the speed signal to detect changes in the amplitude of the pressure signal, which occur at multiples of the rotational frequency of the fan rotor (24). The changes indicate differences in pressure between the gas flow around a damaged fan blade (24) and the gas flow around the remainder of the fan blades (24). The processor unit (40) sends a signal indicative of damage to a fan blade (24), if the difference in pressure is above the predetermined level, to an indicator device (44, 46).

Abstract: A vibration damper 46 for a gas turbine engine has convergent friction surfaces 48a and 48b and is located radially inward of the platforms 20a and 20b of two adjacent turbine blades. The angle subtended by the friction surfaces 48a and 48b is smaller than that subtended by the angled faces 22a and 22b associated with the platforms 20a and 20b. The center of mass of the damper 46 lies in a plane bisecting the angle subtended by the friction surfaces 48a and 48b. In use the damper 46 is urged radially outwards by centrifugal force so that at least one of the friction surfaces 48a and 48b makes planar contact with at least one of the angled faces 22a and 22b. Vibrational energy is dissipated by the resultant sliding movement between the friction surfaces 48a and 48b and the angled faces 22a and 22b. A secondary vibration damping mechanism arises from the oscillation of the damper 46 between the platforms 20a and 20b.

Abstract: A method of manufacturing a ceramic matrix composite comprises forming a slurry comprising a ceramic sol, filler particles and a solvent and forming laminates of fibers (12). The laminates of fibers (12) are impregnated with the slurry and are stacked (14) on a mold (10). The stack (14) of laminates of fibers (12) is covered by a porous membrane (16), a breather fabric (18) and a vacuum bag (20). The vacuum bag (20) is evacuated and is heated to a temperature of 60° C. for 10 hours to produce a ceramic matrix composite. The ceramic matrix composite is then heated to a temperature of 1200° C. at atmospheric pressure to sinter the ceramic matrix composite.

Abstract: An overthrust protection system for a gas turbine in which fuel is supplied at a controlled flow rate to a combustor (4) of the gas turbine. The overthrust protection system uses a bypass valve (24) to divert fuel flow away from the combustor (4). The opening of this valve is controlled by an overthrust controller (28) to divert fuel flow in response to a detected overthrust condition of the gas turbine. Diverting some of the fuel flow in this manner brings about a reduction in the thrust, allowing the overthrust condition to be controlled without resorting to a complete shut down of the gas turbine.

Abstract: A sealing element (30) for a turbine of a gas turbine engine includes a radially inner surface region provided with an integrally formed seal structure (38) comprising a plurality of radially inwardly projecting walls (40). The walls may be abradable and may define cells (44) for receiving an abradable sealing material.

Abstract: A stage of turbine blades (40) in a gas turbine engine (10) is surrounded by an array of shroud segments (42). The upstream ends of the segments (42) have plenum chambers (54) into which cooling air is fed from a compressor (12) via one hole (66) of a pair of holes, the other being numbered (68). Air from the plenum chambers (54) passes out to film cool the interior surface of each respective segment (42). Air from holes (68) passes out to convection cool the exterior surface of each segment (42), which effect is enhanced by the provision of ribs (80) and fences (82).

Abstract: A gas turbine engine fan blade containment assembly (38) comprising a generally cylindrical, or frustoconical, metal casing (40) has an upstream portion (56), a transition portion (58) and a blade containment portion (54). The upstream portion (56) has a flange (42) connecting the metal casing (40) to a flange (48) on axially adjacent casing (46). The blade containment portion (54) has a greater thickness (T2) than the thickness (T1) of the upstream portion (54). The transition portion (58) connects the blade containment portion (54) and the upstream portion (56) to transmit loads from the blade containment portion (54) to the flange (42) on the upstream portion (56). The ratio of the thickness (T4) of the flange (42) on the upstream portion (56) to the thickness (T1) of the upstream portion (56) is between 3 to 1 and 6 to 1.

Abstract: A locking device (36) for use in retaining an assembly of rotor blades against movement around a rotor disc on which they are mounted comprises a body member having first and second portions interconnected by a weakened region (66) whereby a force applied to turn the first portion (38) relative to the second portion (40) can cause them to shear apart at said weakened region (66) thereby facilitating release of seized devices to enable blade removal.

Abstract: A data processing method and a computer based data processing system for use in providing, or optimising, an industrial procedure for generating a product. The system comprising digital processing means, and digital storage means. The storage means having a database stored therein comprising (a) data defining generic product descriptions in terms of physical and/or functional elements and associated properties; b) data defined a plurality of generic process descriptions in terms of process activities, activity sequence, and associated process capabilities, at least one of said generic process descriptions including an iterative set of process activities, and; c) data defining rules relating to a) and b). The method comprising providing the system with specific product information for the product.

Abstract: A fluid flow control valve (60) comprises a valve seat (62) and a valve stem (64) which is movable towards or away from the valve seat (62) to control the fluid flow through the valve (60). A magnetostrictive element (66) is arranged to move the valve stem (64) towards the valve seat (62) and a spring (68) is arranged to move the valve stem (64) away from the valve seat (62). A valve wall (70) encloses the valve seat (62), valve stem (64), spring (68) and magnetostrictive element (66). A magnetic coil (72), a keeper (74) and a permanent magnet (76) are arranged around the valve wall (70). The fluid flow control valve (60) is used to modulate the supply of fuel to a gas turbine engine combustion chamber to reduce combustion noise especially in premixed lean burn combustion chamber. The advantage is that there are no seals in the valve wall where leakage may occur and the valve is modular.

Abstract: An air cooled guide vane (20) is provided with a stack of ducts (40) each of which converges towards its outlet end. Air flow turbulators (42) are positioned in ducts (40) and pressure losses in the air flow brought about by flowing over the turbulators (42), is recovered by the constricting effect of the ducts (40).

Abstract: A hot forming die (10) has forming surfaces (16, 18) and the forming surfaces have a nickel oxide layer (20). A stop off material coating (22) builds up on the nickel oxide layer (20) in operation. A method of cleaning the forming surfaces (16, 18) of the hot forming die (10) includes washing the forming surfaces (16, 18) of the hot forming die (10) in water to remove the stop off material (22) without removing the nickel oxide layer (20) from the forming surfaces (16, 18). The forming surfaces (16, 18) may be soaked in water (26) and/or a jet (30) of pressurized water may be directed onto the forming surfaces (16, 18). The stop off material is quickly removed without damaging the forming surfaces (16, 18). The retention of the nickel oxide layer (20) improves the quality of the hot-formed articles and the interval between cleaning of the hot forming die (10) is increased.