Abstract: The invention relates to a bypass turbojet comprising a primary duct, a secondary duct, a low-pressure compressor, a high-pressure compressor, and a structural intermediate casing arranged axially between said low-pressure compressor and said high-pressure compressor, said intermediate casing being equipped at its periphery with a plurality of support arms having platforms which internally delimit the secondary duct, in which bleed-off means are provided, allowing some of the gaseous stream delivered by the low-pressure compressor to be tapped off and led to the secondary duct. Said bleed-off means comprise means for tapping air from said primary duct which are arranged upstream of said intermediate casing and means for removing the air tapped from said secondary duct downstream of said support arms, these means comprising conduits arranged around said intermediate casing under said platforms.

Abstract: The invention relates to a fixed guide vane assembly comprising a circular casing composed of at least two parts (11) and supporting sectors (5), each composed of an inner segment (7) and an outer segment (6) connected by vanes (8). The parts of the casing and the sectors of the guide vane assembly are held together by a system forming a slide and a slider. Anti-rotation means (30) are provided to prevent the sectors from rotating with respect to the casing.

Abstract: An electrohydraulic device for varying the pitch of the blades of a machine rotor, the blades being mounted on a hub rotated by a drive shaft of the machine, and each blade having a root capable of pivoting about a longitudinal axis of the blade, the drive shaft itself being rotated relative to a stationary structure of the machine, the device comprising firstly a hydraulic actuator whose piston is secured to a control and synchronization ring in which off-center wrist pins are engaged, each fixed in register with one of said blade roots, and having a cylinder closed by a cover that includes a high pressure hydraulic pump feeding hydraulic fluid to both faces of said piston via channels integrated in said cylinder of the actuator, and secondly an electric motor controlled and powered by an electricity generator comprising an inductor secured to said stationary structure of the machine and an armature secured to said drive shaft of the machine.

Abstract: An electrohydraulic actuator comprising: a hydraulic actuator comprising a piston secured to a member to be controlled and capable of moving in a cylinder under drive from a hydraulic fluid; a hydraulic pump feeding both faces of the piston with hydraulic fluid via channels integrated in the walls of the cylinder; an electric motor immersed in the hydraulic fluid, and controlled and powered electrically by an electronic control unit, driving the hydraulic pump in rotation; and a hydraulic accumulator for compensating variations in the volume of the hydraulic fluid; the hydraulic actuator, the hydraulic pump, the electric motor, and the hydraulic accumulator having a common axis of symmetry and being mounted in alignment in a common housing that is leaktight to the hydraulic fluid, thereby forming an axially symmetrical self-contained hydraulic assembly.

Abstract: At least one gaseous precursor of the deposit to be made and comprising an aluminum compound is brought with the help of a carrier gas into contact with the surfaces of parts placed in an enclosure. The carrier gas is selected from helium and argon, and the pressure inside the enclosure is selected in such a manner that the mean free path of the carrier gas molecules is at lest twice as long as that of argon molecules under atmospheric pressure. The method is particularly suitable for aluminizing a low pressure turbine ring sector of a turbomachine, the sector being provided with an abradable honeycomb coating.

Abstract: At least one gaseous precursor of the deposit to be made comprising an aluminum compound is brought by means of a carrier gas into contact with the surfaces of the part which is placed inside an enclosure. The carrier gas is selected from helium and argon and the pressure inside the enclosure is selected in such a manner that the mean free path of the carrier gas molecules is at least twice as long as that of argon molecules under atmospheric pressure. The method is suitable in particular for aluminizing gas turbine blades that have internal holes and cavities.

Abstract: A process for attenuating noise generated in a turbomachine by the interaction of rotor blades with stator vanes downstream of the rotor blades comprises the injection of a fluid in continuous jets upstream of the blades through a number of orifices equal to the number of vanes. The orifices are arranged in a ring and are capable of pivoting about the rotor axis by an angle at least equal to the angular pitch between two consecutive vanes. The angular position is controlled so that the sound waves produced by the interaction between the jets and the blades are of opposite phase to those produced by the interaction of the blades with the vanes.

Abstract: A jet engine suspension comprises a master component for attachment, fixed to an aircraft pylon. If it breaks and if the situation arises where the fixing screws are no longer able to transmit force, a peg takes over: the master component collapses until an upper shoulder rests on the pylon and supports this component. The peg is free of dynamic stress in normal service and there is absolutely no risk of it cracking in fatigue.

Abstract: The present invention relates to an axisymmetric structural component, one of the ends of which is fitted with an inner circular flange for assembling, by bolting. The axisymmetric structural component with a second axisymmetric structural component. The flange comprises housings for receiving fixing elements such as bolts, pins or threaded rods. The housings are arranged on the circumference of the said flange at regular intervals. Each housing is, in longitudinal section (A—A) along a plane passing through the rotational axis of the component, T-shaped and consists of a first essentially cylindrical portion which is longitudinally open on the inner face (x) of the axisymmetric structural component and transversely open on the contact face (y) of the flange in the assembly. A second essentially semi-cylindrical portion is mounted on the flange which is also longitudinally open on the inner face (x) of the said structural component having an essentially D-shaped transverse section.

Abstract: In order to make labyrinth seal lips on the periphery of a metal moving part of a turbomachine, a thick layer of refractory material that adheres to the metal is made prior to assembling the moving part, the refractory material advantageously comprising at least one metal selected for example from Fe, Co, and Ni, together with at least one ceramic selected for example from borides, nitrides, carbides, and refractory oxides. The labyrinth seal lips that are to be made are machined to their final dimensions in the deposited thick layer.

Abstract: A method for extending the life of the attachments that attach blades to rotors, particularly for aerojet engines. Such a method is notable in that it employs intensive ultrasonic peening of the grooves and of the roots of the blades, this peening being performed with an Almen intensity at least equal to F8A, so as to increase the compressive prestress in the contact surfaces without increasing the roughness of these surfaces.

Abstract: A low of compressed air originating from a compressor stream (3) is drawn off through first orifices (13) towards ducts (5, 6) leading outside the casing, creating a flow division through adjacent cavities (11, 12) in the casing (1). These arrangements make it possible to carry a large air flow even if the cavity cross sections (11, 12) are small.

Abstract: The hydrostatic fluid bearing comprises a cylindrical stator having orifices for introducing a fluid under pressure, on its inside surface the stator has a split ring constituted by an assembly comprising a plane metal plate and a layer of self-lubricating composite material. The layer of composite material has cells for surrounding orifices for introducing fluid under pressure, once the assembly has been put into place inside the stator.

Abstract: A gas turbine blade for an airplane engine, comprising in its central portion at least a first central cooling circuit comprising at least first and second cavities extending radially on the concave side of the blade, at least one cavity extending on the convex side of the blade, an air admission opening at a radial end of the first concave side cavity for feeding the first central cooling circuit with cooling air, a first passage putting the other radial end of the first concave side cavity into communication with an adjacent radial end of the convex side cavity, a second passage putting the other radial end of the convex side cavity into communication with an adjacent radial end of the second concave side cavity, and outlet orifices opening out into the second concave side cavity and through the concave face of the blade.

Abstract: A gas turbine blade for an airplane engine, the blade comprising at least a first cooling circuit comprising at least a concave side cavity extending radially beside the concave face of the blade, at least a second cooling circuit comprising at least one convex side cavity extending radially beside the convex face of the blade, and at least one third cooling circuit comprising at least one central cavity situated in the central portion of the blade between the concave side cavity and the convex side cavity, at least one leading edge cavity situated in the vicinity of the leading edge of the blade, communication orifices opening out into the central cavity and into the leading edge cavity, and outlet orifices opening out into the leading edge cavity and through the leading edge of the blade.

Abstract: A method of manufacturing a blisk comprises the steps of cutting a disk to a rough shape comprising a hub with a plurality of blade blanks projecting radially therefrom, machining each blade blank by tangential milling using a tool with a rotation spindle perpendicular to the radial direction to make repeated radial passes, the tool being turned through a facet angle with respect to the disk between each pass. Each blade blank is thus milled to a blade having faceted surfaces. Preferably, the width of each facet is smaller that 5 mm, and adjacent facets subtend angles smaller than 5°, or even more preferably smaller than 3°.

Abstract: An apparatus for axially retaining rotor blades to an annular radially extending disk having a recess and a flange. An annular retaining ring is disposed in the recess and includes an axially extending lip and an axially outer side forming an annular bevel surface along a radially outer edge. A retaining plate having an axially extending base, a radially extending outward arm and a radially extending inward leg having an annular bevel surface along an axially inner, radially inner edge is affixed to the disk and the leg cooperates with the lip of the ring. Wherein, the bevel surfaces of the retaining plate and retaining ring are arranged outwardly opposite to one another so that the bevel surfaces are radially compressed along each other as the base slidably engages with the recess walls.

Abstract: The invention relates to a method for the ultrasonic peening of annular recesses for the attachment of blades to a rotor rim, these recesses including a blade introduction opening. According to the method, a plurality of beads is placed on a vibratory surface of a sonotrode, arranged in an intermediate position in a sleeve having opposed closing-off means capable of sliding in the recess, the introduction opening is placed facing the sonotrode, the sonotrode and the sleeve are moved together toward the introduction opening into a peening position in which the closing-off means face the recess ends opening into said opening, then the rotor rim is turned about its axis so as to bring the closing-off means into a first end of the recess so as to form a closed chamber containing the beads. The rim is turned and the vibratory surface is vibrated to mobilize the beads within the chamber, thereby peening the recess.

Abstract: An injection system for a turbomachine combustion chamber, the system comprising a fuel injection nozzle for vaporizing fuel in the combustion chamber and a mixer/deflector assembly coaxial with the injection nozzle and serving to mix fuel and oxidizer and to diffuse the mixture in the combustion chamber, said mixer/deflector assembly comprising a primary swirler and a secondary swirler disposed at a determined distance apart from each other in the axial direction and separated by a Venturi device disposed coaxially with the injection nozzle, the primary swirler being fixed securely to the injection nozzle and being spaced apart therefrom by a constant radial distance which is determined in such a manner that the fuel vaporized by the injection nozzle can under no circumstances impact on the primary swirler. The Venturi device preferably has an inside surface that presents an upstream portion with a slope discontinuity P.

Abstract: The invention relates to an apparatus and to a method for the surface treatment and compressive prestressing by peening of a wall of at least one oblong cavity formed in a part, said cavity opening to the outside via a lateral mouth and having two ends presenting frontal openings. The wall of the cavity is ultrasonically peened by mobilizing a plurality of beads in a chamber delimited by said wall of said cavity, a vibratory surface closing off said mouth of said cavity, and closing-off means closing off said openings, by means of a sonotrode excited by means for producing ultrasonic oscillations. The method and the apparatus are particularly intended for treating a turbine disk comprising a number of axial recesses formed in the periphery of said disk and having wall portions which diverge from each mouth.