Abstract: A disc for use in an axial flow turbomachine having a main flow annulus which includes an inner flow boundary defined by axially adjacent stator vane and rotor blade platform sections. The disc comprises an axially extending sealing member which extends from its radially outer periphery to bridge the gap between adjacent rotor blade and stator vane platform sections. The sealing member is formed integrally with the disc. The arrangement minimises the unsealed stator well region between the rotatable and non-rotatable platforms and thereby provides for improved operational flow stability.

Abstract: A ducted fan gas turbine engine is provided with a thrust reverser which comprises doors which deflect the fan exchaust efflux. Each door is pivotably attached at its downstream end to a common support member by a frangible coupling. In the event of an unintended in-flight deployment of the thrust reverser, the frangible couplings fracture to permit the doors to move to a non-thrust deflecting position.

Abstract: A solid oxide fuel cell stack comprises a plurality of first modules and a plurality of second modules stacked alternately. Each first module comprises a first distribution member which defines internal passages for the supply of a first reactant to the fuel cells. The first distribution member is enclosed by a porous support structure which carries the fuel cells on its two parallel surfaces. A plurality of passages are defined between the porous support structure and the first distribution member which distribute and remove the first reactant from the anodes. Each second module comprises a second distribution member which defines internal passages for the supply of a second reactant to the fuel cells. The passages in the first distribution member contain a catalyst for steam reforming the fuel. The catalyst is in intimate thermal contact with the fuel cells. Additionally a low temperature adiabatic preformer supplied with hydrocarbon fuel prereforms the fuel and supplies it to the passages.

Abstract: An annular combustion chamber for a gas turbine engine is provided with a plurality of fuel injection nozzles at its upstream end to direct swirled flows of fuel and air into the chamber. Ports in the combustion chamber walls direct air into the combustion chamber to oppose the swirling fuel and air flows from the fuel injection nozzles to achieve better fuel and air mixing.

Abstract: An apparatus for inspecting single crystal specimens comprises an x-ray generator which supplies x-rays to a collimator. The collimator has a matrix of apertures to produce a plurality of parallel x-ray beams which are directed onto a surface of the specimen. An x-ray detector detects the x-ray beams diffracted from the surface of the specimen, corresponding to each of the parallel x-ray beams. At each symmetry pole of an overall Laue pattern an accurately predictable pattern of spots is produced on the x-ray detector, if the orientation and shape of the specimen crystal is known. Each spot corresponds to where one of the diffracted beams strikes the detector. A disarrangement of one or more of the spots indicates a difference in crystal orientation.

Abstract: A plurality of workpieces are assembled into a stack. Two of the workpieces are machined on one surface at predetermined positions from the edges of the workpieces. The workpieces are stacked so that the machined surfaces of the workpieces face away from each other. Two workpieces are provided with a stop off material on one of their surfaces to prevent diffusion bonding at predetermined positions. The edges of the workpieces are welded together and a pipe is welded to the stack to interconnect with the stop off material to form a sealed assembly. The workpieces are diffusion bonded together. The integral structure formed is heated and opposite ends of the integral structure are twisted relatively to contour the integral structure to a predetermined shape. The integral structure is heated and the machined portions on the workpieces are isothermally forged and then the twisted integral structure is internally pressurised to superplastically form one workpiece to produce an article, eg a fan blade.

Abstract: A stage of fan blades in a ducted fan gas turbine engine have the spaces between them filled by a rotary annulus wall filler which has a leading portion made from metal and a trailing portion made from a composite material. The metal portion resists the impact damage from the ingress of foreign bodies and the trailing portion provides a lighter structure.

Abstract: A combustion chamber assembly comprises a plurality of tubular combustion chambers which have their axes arranged generally radially. A transition duct is provided for each of the tubular combustion chambers. Each transition duct has a circular upstream end arranged coaxially with the downstream end of the respective tubular combustion chamber. An annular resilient member mounts the upstream end of the respective transition duct on a tubular portion of a respective support structure. The inner end of the annular member is formed integrally with the upstream end of the transition duct and the outer end of the annular member is secured to a flange on the tubular portion of the support structure by a bolted connection. The annular member has a plurality of circumferentially extending slots to allow thermally induced articulation and to maintain the upstream end of the transition duct coaxial with the support member.

Abstract: A plate-fin type of heat exchanger (400) facilitates exchange of heat between two process streams (S1, S2) e.g. high pressure methane and seawater. It comprises a matrix (M) of heat exchange plate elements (200') arranged side-by-side, flow passages (401) for the seawater process stream (S2) being defined between adjacent plate elements. The plate elements (200') are a high-integrity diffusion bonded sandwich construction comprising two outer sheets (101, 103--FIG. 3) and a superplastically expanded core sheet structure (102--FIG. 3) between the two outer sheets. The sandwich construction provides flow passages (117') for the methane process stream. Adjacent plate elements (200') are held in position relative to each other by serrated racks (403) which engage the edges of the plate elements.

Abstract: A ceramic composite material comprising matrix material, reinforcing fibers and an intermediate interface material. The matrix material and reinforcing fibers consist of the same or different ceramic oxides having a melting point above 1600.degree. C. The interface material is applied as a coating on the fibers and consists of at least one ceramic oxide not exhibiting solid solubility, eutecticum below the temperature of manufacture or use or reactivity with any of the matrix or reinforcing materials. The matrix and reinforcing materials are substantially pure, and the combination fiber/interface material/matrix material is selected from the group consisting of: Al.sub.2 O.sub.3 /Al.sub.2 TiO.sub.5 /Al.sub.2 O.sub.3, YAG/Al.sub.2 TiO.sub.5 /Al.sub.2 O.sub.3, Al.sub.2 O.sub.3 /YAG/Al.sub.2 O.sub.3, Al.sub.2 O.sub.3 /SnO.sub.2 /Al.sub.2 O.sub.3, YAG/SnO.sub.2 /Al.sub.2 O.sub.3, Al.sub.2 O.sub.3 /mullite/Al.sub.2 O.sub.3, and mullite/ZrO.sub.2 /mullite.

Abstract: A gas turbine engine with first and second axial flow compressors and an intercooler therebetween is provided with a bend diffuser and a radial flow diffuser to diffuse the air leaving the downstream end of the first axial flow compressor at a first radial distance from the axis to the upstream end of the intercooler at a second radial distance from the axis. The bend diffuser comprises a first radially outer wall and a second radially inner wall. The first wall is elliptical and the second wall has a profile derived from a relationship between the local area ratio and the path length around the arc such there is rapid diffusion in the bend diffuser without fluid flow separation from the first wall.

Abstract: A hollow turbine blade has cooling air feed passages in the wall defining the central cavity. The wall surfaces of the feed passages slope away from the central cavity in a diverging manner, so as to reduce the step difference in metal thickness between the passages relative to the thickness of metal dividing each passage and the central cavity. The temperature gradient from the blade external surface and the wall surface of the central cavity is thus also reduced, avoiding thermal stresses.

Abstract: A method of making an integrally bladed disc for a gas turbine engine, the disc having at least one blade the radially outermost surface of which is coated with a material harder than that of the blade, the method comprising the steps of: providing a forged disk blank of a first material; friction surfacing at least part of the circumference of the blank with a second material harder than the first material; and machining the blank so as to provide an integrally balded disc wherein the radially outermost surface of at least one blade is coated with said second material.

Abstract: A method of manufacturing a composite material which comprises ceramic fibers in a matrix of a ceramic material. A woven mat of ceramic fibers having an electrically conductive coating thereon is immersed in a sol. The sol comprises surface-charged ceramic particles. A potential difference is applied between the fibers and a second electrode placed in the sol. The applied potential difference is continued until the mat is permeated by the ceramic particles in the sol. The mat is removed from the sol and is then heated to sinter the permeated ceramic particles.

Abstract: A solid oxide fuel cell stack includes a core region which comprises a plurality of first modules and a plurality of second modules stacked alternately. Each first module comprises a first distribution member formed from two corrugated ceramic plates which define internal passages for the supply of a first reactant to the fuel cells. The first distribution member is enclosed by a porous support structure which carries the fuel cells on its two parallel surfaces. A plurality of passages are defined between the porous support structure and the first distribution member which distribute and remove the first reactant from the anodes. Each second module comprises a second distribution member formed from two corrugated ceramic plates which define internal passages for the supply of a second reactant to the fuel cells. A plurality of passages are defined between the fuel cells and the second distribution member which distribute and remove the second reactant from the cathodes.

Abstract: A silicon-enriched aluminide coating for a superalloy article has a composite microstructure including a plurality of bands of silicon rich phases (S.sub.1, S.sub.2, S.sub.3) and a plurality of bands of aluminum rich phases (A.sub.1, A.sub.2, A.sub.3), these bands being spaced apart through the thickness of the coating. The composite microstructure is created by depositing a slurry containing both silicon and aluminum in elemental or pre-alloyed form on the article and heating the coated article above the melting temperature of aluminum to cure the coating, the depositing and curing steps being repeated at least once before diffusion heat treating the resulting layers. Thereupon, all the above process steps are repeated at least once.

Abstract: Measures are disclosed for modifying the boundary layer flow over fluid dynamic surfaces using patterns of riblets which are set at a peak-to-peak spacing substantially less than 80 wall units and which are provided with boundary layer suction means comprising apertures (A) between the riblets for a combinative improvement of boundary layer flow. In a further aspect, riblets are employed in combination with wall apertures as an improved means of shock wave (W) control by permitting recirculation of boundary layer fluid from downstream to upstream of the shock wave.

Abstract: A duel fuel gas generator (10) is provided with a steam injection system (48) having a bleed-off valve (66) and a steam metering valve which are controlled in concert by a controller (50) to supply steam to a steam manifold (22) for injection into the gas generator at rapidly variable rates independent of the steam supply rate from a boiler (42, FIG. 1 ). A proportion of the system can be preheated using a steam warm-up flow through the bleed-off valve (66). A further portion of the system can be purged and preheated using compressor delivery air to flow through a steam metering valve (80), a purge valve (74) and a drain valve (94). To control the degree of superheat at the steam manifold (22), water can be injected through a metering valve (90) and a vortex mixer (92), and to purge condensation from a gas fuel manifold (30, FIG. 7 ) of the gas generator, compressor delivery air can be allowed to flow through the manifold (30), a supply line (108) and a purge valve (112) to atmosphere.

Abstract: A turbine blade is provided with a shroud having at least one cooling air passage extending through it. A plurality of small apertures in the passage direct cooling air as a film across the outer surface of the shroud thereby cooling it. The shroud is therefore thinner and lighter than previous shrouds which are typically provided with a large number of internal cooling air passages.

Abstract: Each fan blade of a fan blade assembly for a ducted fan gas turbine engine is provided with a key which cooperates with the fan blade root and fan hub to axially lock the fan blade to the fan hub. Each key is deformable under excessive axial loading of its associated fan blade to minimize damage to the fan hub.