Showing papers by "Rolls-Royce Holdings published in 1985"

Blade tip clearance control

Abstract: The invention is particularly concerned with the control of blade tip clearance in high pressure compressors of gas turbine engines. The compressor comprises a rotor assembly having radially extending rotor blades and a stator assembly. The stator assembly comprises an inner casing and a cylindrical wall member spaced radially from the inner casing to form a chamber. The axial ends of the cylindrical wall member seal with and are moveable radially with respect to the inner casing. The casing has radially inner and radially outer stops to limit radial movement of the cylindrical wall member. The cylindrical wall member carries a ring of shroud segments which are spaced radially from the rotor blades by a clearance. A valve supplies relatively high pressure air from the downstream end of the compressor into the chamber to contract the cylindrical wall member onto the inner stops to give optimum clearance during cruise, or connects the chamber to relatively low pressure air in the fan duct by aperture in outer casing by pipes to allow the cylindrical wall member to expand to the outer stops to prevent rubbing during transients.

Axial flow compressor surge margin improvement

Abstract: The casing 28 of an axial flow compressor for a gas turbine engine is provided with a plurality of axially extending circumferentially spaced slots 30 in its internal cylindrical surface 32 adjacent the tips of at least one row of blades 26. A benefit in both stall margin improvement and a reduction in efficiency deficit may be achieved by positioning the leading edge of the slot 30 such that it leads the leading edge 30(a) of the blade 26 by an amount termed the overhang A or by reducing the closed to open ratio m/M of the slots 30. A further reduction in efficiency deficit may be achieved by combining the overhang A which individually gave the best stall margin improvement with a slot closed to open ratio m/M somewhat higher than the value which individually gave the best stall margin improvement.

Rotor aerofoil blade containment

Abstract: A hollow propfan aerofoil blade is provided with grooves which extend between its root and tip portions. The grooves contain filaments which are enclosed within a resin matrix material and are anchored to the root and tip portions. The filaments are arranged to be of sufficient strength to contain any of aerofoil portion of the blade in the event of any structural failure thereof.

Composite material manufacture by shaping individual sheets followed by consolidating the sheets

Abstract: A composite material comprising reinforcing carbon fibres in an epoxy resin matrix is manufactured by stacking alternate layers of resin impregnated fibre and polyester release film, and compressing the stack between shaped formers at a temperature below the resin cure temperature. The layers are than separated and the release film discarded. After re-stacking, the fibre layers are autoclave moulded on an appropriately shaped former at a temperature at which the layers consolidate and the resin cures.

Low drag surface construction

Abstract: A low drag surface construction utilizes a plurality of longitudinally extending, parallel, spaced apart linear vortices extending transversely of the free stream to reduce drag between the free stream and the surface. The surface is provided with stabilizing means which retains the vortices in their relationship with one another but causes them to traverse the surface in the same direction as the free stream but at approximately half the speed. The stabilizing produces a regular variation in boundary flow across the surface and may comprise dynamic means such as sequenced jets of fluid escaping from apertures in the surface.

Molding of composite materials

Abstract: A method of molding a composite material comprising reinforcing fibres enclosed in a resin matrix. Layers of the resin impregnated fibres are laid-up in a suitably shaped die whereupon the laid-up layers are overlaid by a silicone rubber member which generally corresponds in shape with the die. Hydraulic pressure is exerted upon the silicone rubber member so that it urges the laid-up fibres into the configuration of the die. The whole molding apparatus is placed in an oven and its temperature is raised to that at which consolidation of the laid-up fibres occurs and the resin cures. The exerted hydraulic pressure is progressively reduced during heating as the silicone rubber member thermally expands so as to ensure that the pressure exerted by the silicone rubber member upon the laid-up fibres remains substantially constant.

Hollow aerofoil blade

Abstract: A hollow aerofoil cross-section aircraft propeller blade is provided with a tow of KEVLAR fibres internally thereof. The fibres which are anchored to the blade root and tip portions are arranged to be passive under all normal operating conditions of the blade. However in the event of a structural failure of the blade between its root and tip portions the fibres serve to contain the blade tip together with any portion of the blade attached thereto. The invention is additionally applicable to prop-fan and fan blades for gas turbine engines.

Method of manufacture of compressor rotor assembly

Abstract: A compressor rotor assembly comprises a shaft and at least one disc having integral radially extending aerofoil blades which disc is integral with the shaft. The assembly comprises a matrix material in which a plurality of short reinforcing fibres are so disposed that the majority thereof within the shaft are generally axially aligned while the majority thereof within the aerofoil blades are generally radially aligned. At least one filament wound support ring provides radial support for the aerofoil blades.

Metal surface hardening by carbide formation

Abstract: A method of surface hardening a metal surface in which the surface is firstly coated with a colloidal dispersion of graphite and then locally melted, in an inert atmosphere or vacuum, so that the molten metal reacts with the graphite to form a metal carbide. On resolidification, the metal carbide defines a dendritic carbide structure within the metal adjacent its surface.

Rotor tip clearance control devices

Abstract: A shroud for a gas turbine engine rotor stage is divided into a number of arcuate segments each of which is a trapezium. The segments are urged together by compression springs which attempts to make the assembly lengthen peripherally, by virtue of the chamfered ends 30 of the segments riding up each other. The completely circular shape of the shroud prevents that movement but as a result, a hoop load is generated which tends to move the segments radially outwards, thus achieving the same effect, along with a consequent increase in diameter. A cam ring and pins are used to control and reverse the movement, as desired. The shroud diameter can thus be altered to suit rotor expansion and contraction.

Radiation probe and method of use

Abstract: A radiation probe includes an optionally cooled tube 10 with a window 22 at one end, and can be traversed across a gas turbine engine combustion chamber 20 by drive means 26. A radiation detector 28 simultaneously measures radiation intensity at a plurality of wavelengths, at each of a succession of positions during the traverse. From this data, local values of radiation levels, grey and non grey absorption coefficients, local temperature and local gas composition and soot concentration are calculated, using a recurrence formula which relates intensities at neighboring positions.

Improvements in or relating to gas turbine engines

Abstract: A gas turbine engine component support assembly (30) comprises a pair of ring members (64) and (74) defining a slot in which a cranked flange (28) extending from the inner surfaces of an array of combustion chamber discharge nozzles (22) is located. One part (28B) of the cranked flange has projections (28C) which engage with radial slots (76) formed in one of the ring members (74) to provide cross-key location of the discharge nozzles. the support assembly (30) is located adjacent the radially inner platform of an array of nozzle guide vanes (20), and also provides support and location for the vanes.

Vectorable exhaust nozzle for a gas turbine engine

Abstract: A vectorable nozzle (17) comprises a fixed first duct (21), a rotatable second duct (22) scarfed at its downstream end, and a rotatable third duct (23) scarfed at its upstream end. The second and third ducts (22, 23) are mounted in bearings (24,26), respectively, and an epicyclic gear train (30) is provided to rotate them in opposite directions while maintaining the direction of gas efflux issuing from the nozzle (17) in a single plane.

Personal handwriting verification

Abstract: The stress-wave activity produced by the interaction between a writing instrument and a surface during the generation of a given piece of handwriting on the surface is detected and stored. The stress-wave activity produced by a subsequent generation of the given piece of handwriting is then compared with that produced by the initial piece of handwriting in order to determine whether the initial and subsequent handwriting pieces have a common author.

Air cooled gas turbine aerofoil

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.

Integral rocket and ramjet engine

Abstract: An integral rocket and ramjet engine (16) comprises, in flow series, an intake duct (18) for aerodynamically compressing air, a port cover (30), a combustion chamber (20) and a propelling nozzle (22). The port cover (30) in a first position prevents air from entering the combustion chamber (20) and enables a rocket charge (24) to be burnt in the combustion chamber (20) thereby accelerating the engine to sufficient velocity for ramjet operation. The port cover (30) is movable axially to a second position when the rocket charge (24) is spent to allow compressed air into the combustion chamber (20) and the engine (16) to operate as a ramjet. In the second position the port cover (30) provides a quiet zone (52) which is substantially shielded from the main flow of air into the combustion chamber. Combustion equipment such as primary and main fuel manifolds (42,46) and flame gutters (50) are also movable with the port cover (30).

Rotor or stator blades for an axial flow compressor

Abstract: A rotor or stator blade for an axial flow compressor has one or both of its end portions designed to minimize the interference between the annulus boundary layer and the blade. The basis of the invention is that the aerofoil is designed so that each section of the aerofoil through the boundary layer performs a constant amount of work per unit height.

Jet pipe for jet propulsion in aircraft

Abstract: A jet pipe for jet propulsion in aircraft has in flow-series a first or fixed duct 13, a second duct 14 and a third duct 15. The second duct 14 is supported on the first duct 13 for rotation about a common axis 13A, 14A of these two ducts. The third duct 15 is supported on the second duct 14 for rotation about an axis 19A having an angle oblique the axis 14A of the second duct. A ring 30 is supported on the second duct 14 for rotation about the axis 14A thereof. A bracket 31 mounted on the ring 30 has a guide and slide connection 32,33 with the third duct 15. A single drive shaft 24, mounted on the fixed duct 13, is connected to rotate the second duct 14 and the ring 30 in opposite directions. The guide and slide connection effects a corresponding rotation of the duct 15 about the axis 19A. The resulting relative rotation of the ducts 14,15 results in the duct 15 moving so that the axis 15A thereof moves through an angle β while remaining in a given plane 11A, 11B.

Analyzing fluid flows within hollow bodies

Abstract: Carrier particles, e.g., of metal or metal oxide, are doped with a positron-emitting isotope and injected into fluid flowing in a body, such as a gas turbine engine. The positrons decay on coming to rest, giving two gamma rays which are detected, and a 3D image is built up. The particles are capable of stopping a portion of the positions before they escape from the particles into the surroundings; thus the gamma rays indicate more accurately the position at which the positron was emitted, and give a clearer image.

Diverter valve with bypass duct obturator

Abstract: A fluid flow diverter system for use with twin engine vertical take-off aircraft. The diverter sysstem is employed to direct a portion of, or all, the working fluid from the first axial flow compressor (14) of either a by-pass engine, a twin fan engine or a variable cycle engine to either a pair of vectorable front nozzles (36) or to a by-pass duct (34). In the event of one engine failing in flight, an attempt at balancing the remaining thrust for vertical landing is made by ducting all the air normally existing from the operative engine's front nozzle (36) across to the inoperative engine's front nozzle (36).

Appareil de combustion pour turbo-moteur

Abstract: UNE CHAMBRE ANNULAIRE DE COMBUSTION22 D'UN TURBO-MOTEUR COMPREND UNE PAROI AMONT32. LA PAROI32 PRESENTE UNE PLURALITE D'OUVERTURES50 ESPACEES DE LA MEME DISTANCE ET UN POT CONVERGENTDIVERGENT52 EST POSITIONNE COAXIALEMENT A CHAQUE OUVERTURE50 ET S'ETEND VERS L'AMONT. CHAQUE POT52 COMPORTE UN ORGANE RADIAL DE TOURBILLONNEMENT54 A SON EXTREMITE SUPERIEURE QUI LUI FOURNIT DE L'AIR. UN INJECTEUR DE CARBURANT56 EST ALIGNE AVEC CHAQUE POT52 ET AVEC L'ORGANE DE TOURBILLONNEMENT54 POUR FOURNIR DU CARBURANT AU POT52. UNE PLURALITE DE DEFLECTEURS ANNULAIRES D'AIR58 S'ETENDENT VERS L'AMONT A PARTIR DE LA PAROI AMONT32 ET CHAQUE DEFLECTEUR EST PLACE COAXIALEMENT AUTOUR D'UN POT 52 POUR FOURNIR DE L'AIR A L'ORGANE DE TOURBILLONNEMENT. L'EXTREMITE AVAL DE CHAQUE POT52 COMPORTE DES OUVERTURES68 POUR FOURNIR DE L'AIR DE REFROIDISSEMENT A LA FACE AVAL DE LA PAROI AMONT32.

Enveloppe amelioree de conduit de soufflante

Abstract: ANNEAU DE CONTENTION POUR CONDUIT DE SOUFFLANTE DE MOTEUR A TURBINE A GAZ 10 COMPRENANT UN CYLINDRE RIGIDE 22 DONT LA SURFACE EXTERNE EST RECOUVERTE PAR DES COUCHES D'UN MATERIAU FIBREUX CONSTITUEES D'UNE PLURALITE DE PIECES DE MATERIAU TISSE, AUTOUR DESQUELLES EST ENROULEE UNE DEUXIEME PLURALITE DE COUCHES CONTINUES D'UN MATERIAU FIBREUX TISSE QUI EST ENSUITE RECOUVERTE PAR UNE AUTRE COUCHE ETANCHE.