Abstract: A swirler for a gas turbine engine combustor is disclosed for simultaneously controlling combustor flow rate, swirl angle, residence time and fuel-air ratio to provide three regimes of operation. A first regime is provided in which fuel-air ratio is less than stoichiometric, NOx is produced at one level, and combustor flow rate is high. In a second regime, fuel-air ratio is nearly stoichiometric, NOx production is less than that of the first regime, and combustor flow rate is low. In a third regime, used for example at lightoff, fuel-air ratio is greater than stoichiometric and the combustor flow rate is less than in either of the other regimes.

Abstract: A catalytic combustor comprises a pilot zone having means to introduce fuel therein; upstream of said pilot zone and communicating therewith a catalytically supported thermal combustion zone comprising a plurality of catalytically supported thermal combustion sections each comprising a solid oxidation catalyst, means for introducing air into said section and means to introduce fuel into said section; and means to control the rate of fuel flow in each of the means to introduce fuel into a catalytically supported thermal combustion section and the means to introduce fuel into the pilot zone. The combustor is operated by staging the fuel supply in order to maximize the amount of combustion in the catalytically supported thermal combustion zone and minimize NOx emissions under all load conditions.

Abstract: In a jet engine in which the engine cowling includes an inlet cowl and an engine containment case and in which at least a portion of the interior surface of the inlet cowl is covered by an acoustic treatment material, a system for attaching the inlet cowl to the engine containment case icludes an attachment ring that is substantially U-shaped in cross section having a web and first and second legs extending orthogonally from the web. The first leg abuts an engine flange that is a part of the engine containment case. The first leg and engine flange are secured to one another by threaded fasteners. The web is attached to the acoustic treatment material by fasteners that pass through the web and the acoustic treatment material. The acoustic treatment material is effective up to the interface between the inlet cowl and the engine containment case.

Abstract: A gas turbine engine for aircraft. A generator, which undertakes to supply energy for auxiliary devices, is spaced between a compressor and a turbine. A heat exchanger which surrounds the generator housing, and through which compressor air and fuel flow, is provided for cooling the generator. The compressor air which is cooled by the fuel is supplied to the rotor of the generator, and possibly to a bearing of the rotor shaft.

Abstract: In order to combat flutter in rotor blades rotating within a duct bounded by a duct wall, the duct wall incorporates cavities tuned for resonance to a known flutter frequency. The cavities, which may comprise tubes immediately underlying a facing sheet of the duct wall, are arrayed around the circumference of the duct wall and communicate with the duct through openings in the duct wall near the tips of the blades. Flutter energy from the blades is transferred directly to the cavities by pressure waves and produces resonance in the cavities so that the flutter is damped aerodynamically. The invention is applicable to fans in turbofan engines.

Abstract: A hollow turbine blade 10 of aerofoil shaped cross section is provided with walls 18 of varying thicknesses to provide thermal slugging at those regions around the aerofoil profile where the blade experiences high thermal fluxes. The thicker regions of the blade 10 are provided with cooling channels 22 which are elongated in a direction extending from the external surface of the wall towards the internal surface of the wall. The thermal slugging slows down the rate of change of blade wall temperature to a value similar to the rates elsewhere in the blade section. The cooling channels 22 ensure that the temperature gradient across the wall 18 is low around the profile of the aerofoil.

Abstract: A combustor for a stationary combustor turbine is provided with a generally tubular sidewall formed from a telescopic arrangement of sidewall ring members. A corrugated spacer band supports the upstream end portion of each sidewall member on the downstream end portion of the next inwardly located sidewall member in the upstream direction. An annular coolant admission slot is thus provided between the sidewall members with the corrugated spacer band located therein.The downstream end portion of each sidewall member extends as an annular lip projecting downstream from the downstream end of the corrugated band to discourage mixing of the hot internal gases with the coolant air flowing as a film through the slot and along the inner sidewall surface.

Abstract: A turbofan engine having a variable geometry exhaust nozzle.

Abstract: For a long dual mixer nacelle housing a fan-jet engine powering aircraft, a pair of concentric sleeves sandwiching the cascades to effectuate thrust reversal are synchronously deployed axially to communicate the fan discharge air in the duct with ambient through the cascades. A rack and gear connection between sleeves permits the independent linear motion of each of the sleeves so that the actuation of one automatically actuates the other without the necessity of attaching both to each other.

Abstract: A front mounting for an annular combustion chamber comprises a flexible ring attached to an engine casing, and radial struts which are attached to the flexible ring and which engage bushes welded to a semi-circular section upstream wall. The arrangement restrains axial movement of the front end of the combustion chamber relative to fuel burners while the radial movement caused by differential thermal displacement to be absorbed by the flexible ring.

Abstract: Insulation material lines the inner wall of the case of a gas turbine engine and controlled hot and/or cold air is selectively impinged on the outer wall of the case so as to maintain a minimum gap between the outer peripheral edge of the rotating blades relative to their tip seal means for increased thrust specific fuel consumption (TSFC).

Abstract: The invention relates to a propulsion engine, particularly for supersonic aircraft. An internal propulsion system comprises an envelope displaying a tapered center portion, around which is coaxially mounted an external propulsion system which lacks a separate compressor. According to the invention, mechanisms are provided to divert toward the combustion chamber of the external propulsion system an adjustable fraction of the compressed air arriving from the last compressor stage of the internal propulsion system. A blower which is driven by the external turbine exhausts in parallel with the latter into an annular conduit which emerges between the internal nozzle and external nozzle and an exhaust nozzle, all of these nozzles being of variable geometry. The purpose of the invention is to improve variable cycle propulsion engines for second-generation supersonic aircraft.

Abstract: This invention minimizes wakes manifested by a fuel nozzle support structure extending through an annular diffuser engine to the burner in a gas turbine engine, spaced walls extending from the inner and outer wall of the diffuser project toward the nozzle support downstream of the support that passes transverse to the flow, one wall being shaped conically and the other being shaped bell-mouthed and convergent.

Abstract: A mechanism 25 for preventing a turbine rotor 14 exceeding a predetermined speed in the event that a shaft 24 connecting the turbine rotor 14 to a compressor rotor 12 of the engine breaks and releases its torsional and axial constraint on the turbine rotor. The mechanism 25 comprises a segmented nozzle guide vane assembly 26 downstream of a stage of the turbine rotor 14. Each of the segments 26 is pivotally mounted (hinge pins 40) on an outer casing 34 at a region adjacent a radially outer upstream end of each segment 26. The structure of the engine on which the radially innermost ends of the segments 26 are mounted includes a releasable means 46. When the structure 46 is struck by the turbine rotor 14 the innermost ends of the segments 26 are released and allowed to swing rearwards and outwards about the pivotal attachment of the segments 26 to the outer casing 34.

Abstract: An improved diffuser for a gas turbine engine is mounted between a compressor section and a burner section. The diffuser eliminates struts by using the exit guide vanes of the compressor for support. The vanes are fixedly mounted to an inner case wall and to a double outer wall. A cantilevered case wall being one of the double outer walls can flex both radially and axially to relieve thermal stress in the vanes. Additionally, probes can be mounted in access ports formed in the double outer wall. Compressor leakage gas is prevented from entering voids in the double outer wall by a seal seated between the cantilevered case wall and the outer case wall.

Abstract: A bearing chamber pressurization system for a ducted fan gas turbine engine uses fan delivery air at relatively low pressure and temperature for bearing chamber pressurization. In order to avoid the possibility of a flow reversal in the pressurization air when the fan speed is reduced, a second higher pressure air supply from the core engine is made available under the control of a valve and pressure sensing device, and which comes into operation when the ratio of the bearing chamber pressure and the supply pressure reaches a pre-determined minimum.

Abstract: A gas turbine engine air intake comprises an enlarged center body positioned upstream of the engine air inlet. The center body is provided with a drain so that in operation water particles impacting and flowing across the surface of the center body are directed into the interior of the center body. From there the water is drained into a by-pass duct which exhausts the water into the exhaust efflux of the engine to which the intake is attached.

Abstract: Methods and apparatus for improving the thrust specific fuel consumption (TSFC) of a gas turbine engine employing an exterior active clearance control system are disclosed.The pressure within the nacelle compartment to which active clearance control air is discharged is operated under altitude cruise conditions at a level on the order of one to two and one-half pounds per square inch (1-21/2 psi) above the ambient atmosphere. Flow discharging from the nacelle is directed through an aft facing vent nozzle for purposes of thrust recovery.

Abstract: An exhaust mixer for a turbofan aeroengine can be classified as being of the multi-lobed type, with troughs between the lobes. Good mixing efficiency together with good aerodynamics, short axial length and low weight is achieved by forming the mixer from flow surfaces which are longitudinally twisted between their upstream and downstream ends, opposing sides of each lobe and trough being of opposite twist. Between the upstream and downstream ends of the twisted flow surfaces, their latitudinal contours become approximately S-shaped so as to define outer portions of the lobes, inner portions of the troughs and the opposed sides of the lobes and troughs.

Abstract: A gas turbine power unit is disclosed in which the arrangement and configuration of parts is such as to save space and weight in order to provide a compact and self-contained assembly. An air-intake casing (2) supports the upstream end of a gas generator (3), the downstream end of which is integral with a power turbine (4). The stator casing (5) of the turbine (4) is connected to a cone (6) thermally insulated and completely inserted into any exhaust casing (7) having a vertical outlet, wherein the turbine exhaust is conveyed into the exhaust casing (7) by an annular diffusing cone (8). The turbine casing is supported on four legs (15, 16). In addition, the turbine rotor (10) and thus the turbine shaft (11) are overhangingly supported by an independent structure (12), the weight of which bears on the machine base (1) outside the exhaust casing (7) and away of the power turbine space.