Showing papers by "Rolls-Royce Limited published in 1980"

Mounting for gas turbine powerplant

Abstract: A gas turbine powerplant has an inner casing (4A) containing a gas turbine engine, an outer casing (5) surrounding the inner casing, a fan driven by the engine and driving air through an annular duct defined between the casings. The powerplant is connected to an aircraft fuselage (1) by a front mounting (9,9A,9B,9C) and by a rear mounting (8,10,17,18). The front and rear mountings react lateral forces on the powerplant. The powerplant includes a thrust reverser (11) situated rearwards of the rear mounting and supported by a ring (18) lying in the annulus of the outer casing and forming part of the rear mounting. At each side of the powerplant there is provided a tie (14,15) which connects the inner casing at a joint (6,16A) adjacent the front mounting to the ring of the rear mounting. The ties therefore lie oblique to the main engine axis. The ties react the forward and reverse thrusts of the powerplant.

Rotor tip clearance control apparatus for a gas turbine engine

Abstract: A rotor tip clearance control apparatus for a gas turbine engine comprises an annular shroud member which forms part of the static structure of the apparatus. The shroud member has an internal frusto-conical surface which co-operates with the outer extremities of the rotor to define a small clearance. In order to control this clearance the shroud member is mounted from fixed structure by rotatable eccentrics which can move the member axially and thus affect the clearance in a predetermined manner.

Application of metallic coatings to metallic substrates

Abstract: A metallic coating is applied to a metallic substrate by directing a laser beam on to the substrate and simultaneously directing a gas stream containing entrained particles of the coating material on to the area of laser impingement on the substrate. The particles are melted by the laser beam to form a pool of molten coating metal. Relative movement is effected between the laser beam and substrate so that a pool of molten coating metal traverses the substrate to form a solidified metallic coating which is fused to the metallic substrate.

Stator vane assembly for a gas turbine engine

Abstract: A stator vane assembly for a gas turbine engine comprises a plurality of aerofoil sectioned vanes supported from a circumferentially extending support member or casing via a circumferentially extending platform or platforms. Each vane is attached at one end to one said platform which is carried from the supporting member, each platform being relatively flexible so that deflections of its respective aerofoil sectioned vane cause it to deform. The mounting between the platform and the supporting member is such as to damp motion of the platform and thus of the aerofoil sectioned vane; in some instances resilient material may be interposed between the platform and supporting member to provide the damping.

Gas turbine engine fuel burners

Abstract: A gas turbine engine fuel injector which burns liquid and gaseous fuel and also has a water injection system to reduce the formation of nitrogen oxides (NOx). The water can be discharged into a combustion chamber through an annular nozzle which is located between an inner annular fuel and air discharge nozzle and an outer gas discharge nozzle which comprises a circumferential row of discrete discharge nozzles. This allows the water to be injected at the most suitable point whichever fuel is being burnt. The water can also be injected into the inner annular fuel and air discharge nozzle.

Perforate laminated material and combustion chambers made therefrom

Abstract: A perforate laminated material suitable for use in the manufacture of combustion chambers for gas turbine engines comprises two sheets bonded together, each sheet having a plurality of perforations, the laminated material being formed with internal channels which interconnect the perforations in the abutting sheets, the contact area between the two sheets being in the range 18% to 60% of the surface area of one side of one of the sheets and the ratio between the number of perforations per unit area in the sheets being in the range 2:1 to 10:1 in use the sheet having the larger number of perforations being adjacent a relatively hot gas stream.

Gas turbine engine fuel injectors

Abstract: A gas turbine engine fuel injector has distinct and separate flow paths for liquid and gaseous fuel which each terminate in outlets of decreasing cross-sectional area in order to prevent combustion products from the flame tube or tubes of the engine from flowing back into the injector, the separate fuel flow paths preventing fuel from migrating from one path to the other. Compressor delivery air is also arranged to flow through the fuel outlets and some mixing of fuel and air takes in the outlets before the fuel enters the flame tube. The fuel injector is formed in two separate and co-operating parts, a fuel feed arm attached to the engine casing and readily removable through a relatively small access aperture in the casing and a fuel and air inlet means which is attached to the head of the flame tube and defines the fuel and air inlets into the flame tube. The fuel injector is designed to operate on a wide calorific value range of both liquid and gaseous fuels and water injection means are also incorporated to reduce NOx emissions.

Static shroud for a rotor

Abstract: A static shroud for a rotor comprises a shroud ring having a frustoconical inner surface adapted to co-operate with a peripheral portion of the rotor to define a small clearance therebetween. A plurality of actuators are provided to move the ring axially to vary the clearance in a predetermined manner. In order to compensate for eccentricity, the actuators are adapted to tilt the ring out of a radial plane when required.

Casing structure for a gas turbine engine

Abstract: A casing structure for a gas turbine engine comprises an outer load-bearing casing within which is supported an inner casing which forms the static structure of a compressor. Bearing panels carried from the outer casing carry the rotor of the compressor and its associated turbine. In order to mitigate the undesirable consequences of the bending under load of the outer casing, the inner casing is mounted at a forward section by forward mounting means which maintain it concentric with the rotor axis and at a rearward section by rearward mounting means which maintain it parallel with a section of the outer casing which retains its parallelism with the rotor axis even when the casing bends. The forward mounting illustrated is a dogged engagement while the rearward mounting utilizes a parallel series of links as a parallel motion linkage.

Monitoring distance variations

Abstract: An optical device for monitoring variations in the distance between an object and a datum is particularly useful for monitoring running clearances in the demanding environment of a gas turbine engine. The device depends upon the principle that an image focussed by an astigmatic lens system changes shape as it passes through the focus. To monitor variations, e.g., in the working clearance between a turbine blade tip and a turbine casing, light from a light source is projected through an astigmatic lens system, onto the blade tip. Reflected light from the astigmatic image on the blade tip is passed back through the lens system and re-projected onto an image shape monitor which includes photo-cells. The photo-cells may be mounted in the main optical assembly or probe, or they may be distant from the probe and fed by light guides. Signals from the cells are combined to produce a monitor signal, the magnitude of which is a measure of the shape of the image on the blade tip, and hence of the clearance.

Rotor blade for a gas turbine engine

Abstract: A rotor blade for a gas turbine engine comprises an aerofoil, shank portion and a root by which the remainder of the blade may be supported from a rotor disc. Cooling for the aerofoil is provided by passages in the leading portion of the aerofoil which are fed with cooling air from an entry aperture and a sealed liquid cooling circuit which contains a cooling liquid. This circuit comprises a liquid feed passage adjacent the trailing edge of the aerofoil and connected adjacent the tip of the aerofoil with a vapor return passage, both passages communicating with a sealed cavity within the shank of the blade. In operation the cooling fluid (e.g. metallic sodium) flows under the influence of centrifugal and other forces along the feed passage, is vaporized and returns to the cavity via the return passage. The cavity acts as a condenser for the fluid.

Gas turbine engine combustion chambers

Abstract: In a gas turbine engine having a can annular combustion system, the diffusion passage between the outlet annulus of the engine compressor and the inlets to the individual combustion chambers located in an annular housing, is partially defined by diffusion control housings, one of each of which is integral with the upstream end of a respective one of the combustion chambers. Each diffusion control housing is wedge-like in planform and increases in circumferential width and radial height in the downstream direction. An opening is provided to receive a fuel injector and an air outlet or inlets is located at the upstream end of each housing. The air inlet can be in the form of a single opening at the apex of the housing or in the form of an opening in each flank of the housing.

Gas turbine engine power plant

Abstract: A ducted fan propulsion plant has a reversible-pitch fan driven by a core gas turbine engine and housed in a duct which terminates at its downstream end in an outlet nozzle defined between two semi-cylindrical shells. The shells are mounted for movement hydraulically both axially and angularly to define an increased effective nozzle area for take-off. Upon further rearward axial displacement the shells adopt a reverse-thrust position to define air inlets to the fan when the fan blade pitch is reversed.

Cooled shroud for a gas turbine engine

Abstract: A cooled shroud for a gas turbine engine comprises an annular metallic supporting member having holes therethrough for the flow of cooling air and a layered coating on its inner face The layered coating comprises a first layer of porous material through which the cooling air may permeate, and a second layer of impermeable ceramic covering all but selected areas of the surface of the first layer In this way the cooling air is largely constrained to flow along the porous material to provide good cooling with relatively low air flow

Mounting of rotor assemblies

Abstract: A rotor assembly comprising a drive shaft 13 mounted in a first bearing means 22 at a location spaced from a first end of the shaft 13 and supported at the first end by a support means 23 which is more flexible in bending and in torsion than the drive shaft 13. The support means 23 is mounted for rotation in a second bearing 24 which is co-axial with the first bearing 22. A rotor 10 is connected to the first end of the drive shaft 13 to be driven thereby, and is also supported directly in the second bearing means 24 through a frangible coupling 33. The frangible coupling 33 is designed to break the connection between the rotor 10 and the second bearing means 24 only when the rotor 10 is subjected to a predetermined out-of-balance load to allow the rotor 10 and drive shaft 13 to run inverted.

Bladed rotor for a gas turbine engine

Abstract: This invention relates to a bladed rotor for a gas turbine engine which comprises a disc having blade carrying slots in its periphery. In order to seal the spaces between the blade platforms and the disc an annular array of sealing plates is provided. The plates are supported directly from the disc by a rivet, pin or the like which passes through the disc in between the blade carrying slots, in this way avoiding any additional loading on the blades themselves.

Constant speed drive

Abstract: A constant speed drive comprises a frictional variable speed drive controlled by a control system to produce a constant output speed. The drive includes a rotatable disc having a frusto-conical surface and being urged into frictional engagement with a rotatable annulus having a corresponding frustoconical edge, the annulus and disc being relatively movable between a position in which they are coaxial and provide a unity drive ratio and a position in which they are eccentric and provide a different drive ratio determined by the relative positions of their axes. Actuation means are provided for adjusting the positions of the axes of the annulus and disc relative to one another, and the control system controls the actuation means to vary the relative positions of the axes of the disc and annulus and thus the drive ratio to maintain a sensibly constant output speed.

Gas turbine engine having a cooled turbine

Abstract: A gas turbine engine is disclosed in which a particularly efficient use of cooling air is made. In this engine, at least part of the cooling of the turbine blades is effected by a bleed of air from one of the compressors. This bleed air is ducted to flow between the shanks of adjacent rotor blades to cool them, and the used bleed air then rejoins the main gas flow of the engine upstream of the turbine rotor.

Gas turbine engine cowling

Abstract: A gas turbine engine cowling suitable for a helicopter contains a gas turbine engine having a vortex tube separator panel for the purpose of separating water droplets and particulate material from engine inlet air. The vortex tube separator panel is mounted in a duct extending the length of the cowling so that air passing through the duct supplies air for passing through the panel to the engine inlet as well as maintaining a flow of air transverse to the panel. The air flow transverse to the panel ensures that blockage of the panel by ice is substantially reduced or eliminated. Under forward flight conditions, ram air passes through the duct but during hovering, the air flow through the duct is induced by an ejector powered by the exhaust efflux from the engine. The portion of the air flow through the duct which does not enter the gas turbine engine is utilized in the cooling of the engine exhaust efflux in order to reduce the amount of infra-red radiation emitted thereby.

Combustion apparatus for gas turbine engines

Abstract: Combustion apparatus for gas turbine engines has a combustion chamber (4,5) provided with fuel/air mixture injection devices (11) in an upstream end wall (9,10) of the chamber Each device has a passage (17) having inlets (12,15) for air and fuel which mix in the passage and discharge through an outlet (19) initially in a direction along the adjacent surface of said chamber end wall (9,10) The latter wall has a secondary inlet (20) admitting a stream of air transversely to the flow from the passage outlet (19) thereby to generate an oblique flow (19A) having a component movement (Y) away from the combustion chamber wall This directs inflammable mixture away from the latter wall and simultaneously assists mixing of air and fuel A cooling film (24,24A) passing along the chamber wall passes over the passage wall (16) and, in certain examples, between the oblique flow and the chamber wall

Arrangements for drainage of lubricating oil from bearing assemblies

Abstract: A bearing chamber is provided with drains on both sides of the bearing thus preventing oil surges spilling oil over the chamber seals. The bearing chamber has three compartments and the chamber is pressurized by air passing through the seals at its ends. A main drainage duct drains the main bearing compartment via a scavenge pump to the oil tank. Passages through the bearings under normal operation drain oil from the end compartments to the central compartment compartment A. When the main drain becomes ineffective due to sudden surges of oil to the ends of the chamber the oil passes via auxiliary drainage ducts back to the tank due to the pressure in the chamber. Baffles are provided between the bearings and the end walls of the chamber to prevent the oil sloshing over the entrances to the auxiliary drainage ducts at excessive speed thereby providing tranquil zones from which the oil passes into the drainage ducts.

Modular gas turbine engine

Abstract: A modular gas turbine engine comprises a gas generator module and a power turbine module. The shafts carried within each module are mounted on bearings which are arranged such that the downstream bearing of the gas generator module and all of the bearings of the power turbine module are contained within a common chamber which is defined by portions of both the gas generator module and the power turbine module.

Method of applying a ceramic coating to a metal workpiece

Abstract: A method of applying a ceramic coating to a metallic workpiece is proposed in which the workpiece is heated in a range of 500° C. to 950° C. and the coating directly plasma sprayed thereon in an atmosphere of air before the workpiece has formed any considerable oxide skin thereon. In this way the use of the conventional bond coat is avoided, while the amount of tensile stress on the ceramic at working temperature is reduced by the pre-stressing effect thus induced.

V/STOL Aircraft

Abstract: A twin-engined VTOL/STOL aircraft comprising a rearwardly bifurcated fuselage 10 is proposed which in the event of failure of one engine 20 will allow the other engine 20 to produce a thrust which is not assymetric relative to the longitudinal axis of the aircraft. The fuselage 10 comprises a central front nose portion 11 and two side mounted engine nacelles 13, 14 which extend rearwardly to define spaced tail booms 15, 16. The engines 20 are preferably by-pass gas turbine engines in which the turbine exhaust gases are discharged through one or more nozzles 28 to the rear of the nose portion 11 between the tail booms 15, 16 on the center-line of the aircraft. The by-pass air is discharged through one or more nozzles 27 adjacent the longitudinal center-line of the aircraft. The nozzles 27, 28 are either swivellable, or other devices 34, are provided to vary the direction of thrust from the nozzles.

fluid processing device

Abstract: A fluid processing device for use in the oil system of gas turbine or other plant, performs the functions of a de-gassifier and filter for liquid from part of the plant, scavenge pump for returning clean liquid to the plant, air/liquid droplet separator and main pressure pump, or any required combination of these functions. The performances of individual rotary devices are enhanced by the inclusion of a quantity of a rigid porous material having interconnected interstitial passages so that all the rotary devices can operate at the same speed and can thus be driven from a single shaft. In a gas turbine engine application (FIG. 3) the device has a plurality of individual compartments 36,38,40 and 41 within a rotating housing 21, each compartment containing the porous material. Compartments 36 and 38 are supplied with air and emulsified oil via pipes 44 from bearing chambers. The oil and air are separated and the oil is filtered in the compartments, the oil passing via debris collectors 48 into a compartment 34 in which the scoop 50 of a pump returns it to the oil system. The air is vented from the device via compartments 40 and 41 in which further filtering and oil mist separation take place. The main oil pump comprises porous material rotated in compartment 64. The material is supplied with oil from the oil tank via passage 62 and pumps it via a diffusing passage into the remainder of the system.

Resin matrices and their contribution to composite properties

Abstract: As a result of the increasing use of glass and carbon fibre reinforced plastics in aircraft structures, great emphasis is now placed on the choice of a suitable resin matrix for these demanding applications. In practice this choice is frequently a compromise between conflicting manufacturing, design and materials requirements, and is further complicated by the great range in chemical variety of available resin matrices. Uncertainty of quality in the manufactured composite and a failure to observe and report on fracture modes occurring during sample testing are among other factors that interfere with the establishment of a body of reliable experimental data. This paper considers the relation between matrix and composite properties from a number of viewpoints. Examples of materials' requirements for specific component applications are given and, finally, a matrix suitable for aerospace use and factors influencing its formulation is discussed.

Gas turbine rotor support systems

Abstract: A rotor assembly, particularly for a gas turbine engine, comprising a torsionally stiff drive shaft 16 mounted at two spaced locations in first and second bearings 22,23 which are substantially immovable bodily in radial directions. The drive shaft 16 has a flexible end portion 15 constituted by a shaft 25, projecting beyond the first bearing 23 which is more flexible in bending than the span of the drive shaft 16 between the first and second bearings 22,23. A support means 27 is mounted for rotation in a third bearing 28. The rotor 11 is mounted on the flexible end portion 15 of the drive shaft 16 to be driven thereby and is also mounted on the support means 27 for rotation in the third bearing 28. The third bearing 28 is capable of accommodating radial deflections of the support means 27 when the rotor becomes unbalanced.

Tank suitable for holding liquids

Abstract: An oil tank suitable for an aircraft mounted gas turbine engine is divided into three series connected chambers. Aerated oil after engine use is fed into the first chamber and de-aerated oil withdrawn from the third chamber for engine use. The chambers are interconnected in such a manner that when the tank is inverted, a reservoir of oil is retained within the third chamber to provide a continued supply of oil to the oil outlet for a finite time period and insufficient oil flows into the first chamber from the second to obstruct an air vent provided in the first chamber.