Abstract: A turbomachine comprising an annular combustion chamber (40) with injection orifices (44); a centrifugal compressor (10) having a centrifugal downstream stage and an annular diffuser (20) comprising: a radially-oriented upstream portion (21)with diffusion passages (22) connected to the outlet of the compressor and an elbow-shaped intermediate portion (24)and a downstream portion (25) comprising a series of flow-straightening vanes (26) and inclined relative to the axis (A) of the turbomachine. In the section plane containing the axis (A) of the turbomachine and passing via the center (C) of one of said injection orifices (44), the curvilinear abscissa distance along a flow line (L) between the middle (0) of the flow path at the trailing edges of the flow-straightening vanes (26) and said center (C) is greater than or equal to three times the height (h) of said flow path.

Abstract: A fuel injector system for injecting fuel into a turbomachine combustion chamber, the system comprising first and second fuel injectors wherein the first injector (22) is positioned in the center of the injector system (20) so as to inject a first fuel spray (42), and wherein the second injector (28) surrounds the first injector in such a manner as to inject a second fuel spray (48) of generally annular shape around the first fuel spray. The injector system further comprises an air admission duct (22) with outlet orifices (62) opening out between the first and second injectors so as to create a separator air film (f1) between the respective combustion zones of the first and second fuel sprays.

Abstract: A device for injecting a mixture of air and fuel into a combustion chamber of a turbomachine is disclosed. The injection device includes a novel sliding bushing and a novel annular cup for retaining the sliding bushing, making it possible to improve the air feed of the injection device.

Abstract: A gas turbine engine diffuser defined between an external casing and an internal casing of the engine and supplied with air via an upstream annular diffuser duct is disclosed. The diffuser includes a combustion chamber of the convergent type, forming an external annular duct with the external casing and an internal annular duct with the internal casing, and a cowling partially closing off the external annular duct. The cowling is positioned toward the closed end of the combustion chamber.

Abstract: A shroud for a combustion chamber bottom designed to cover fuel injectors is provided with drillings on at least one of its sides to open up the cavity within the shroud and reduce noise that it produces and combustion instabilities. The drillings also have the effect of reducing instabilities and non-uniformity of the airflow around the shroud.

Abstract: The invention relates to a device for injecting a mixture of air and fuel into a combustion chamber of a turbomachine where the supply of air is improved. The invention relates more particularly to a new type of sliding bushing.

Abstract: A turbomachine comprising: an annular combustion chamber (40) with injection orifices (44); a centrifugal compressor (10) having a centrifugal downstream stage; and an annular diffuser (20) comprising: a radially-oriented upstream portion (21) with diffusion passages (22) connected to the outlet of the compressor; an elbow-shaped intermediate portion (24); and a downstream portion (25) comprising a series of flow-straightening vanes (26) and inclined relative to the axis (A) of the turbomachine. In the section plane containing the axis (A) of the turbomachine and passing via the center (C) of one of said injection orifices (44), the curvilinear abscissa distance along a flow line (L) between the middle (O) of the flow path at the trailing edges of the flow-straightening vanes (26) and said center (C) is greater than or equal to three times the height (h) of said flow path.

Abstract: The present invention relates to a gas turbine engine diffuser (30) defined between an external casing (32) and an internal casing (34) of said engine and supplied with air via an upstream annular diffuser duct (36), comprising a combustion chamber (10) of the convergent type, forming an external annular duct (28) with the external casing (32) and an internal annular duct with the internal casing (34), which diffuser comprises a cowling partially closing off the external annular duct. More specifically, the cowling is positioned toward the closed end of the combustion chamber.

Abstract: A fuel injector system for injecting fuel into a turbomachine combustion chamber, the system comprising first and second fuel injectors wherein the first injector (22) is positioned in the center of the injector system (20) so as to inject a first fuel spray (42), and wherein the second injector (28) surrounds the first injector in such a manner as to inject a second fuel spray (48) of generally annular shape around the first fuel spray. The injector system further comprises an air admission duct (22) with outlet orifices (62) opening out between the first and second injectors so as to create a separator air film (f1) between the respective combustion zones of the first and second fuel sprays.

Abstract: The invention relates to the field of turbomachines and concerns a device (20a, 20b) for injecting a mixture of air and fuel into a combustion chamber (4) of a turbomachine (1). It relates more specifically to an injection device (20b) provided with a novel sliding bushing (30b) and with a novel annular cup (50b) for retaining the sliding bushing, making it possible to improve the air feed of the injection device.

Abstract: A carbureted flameholder (30) with optial cooling is provided for a bypass turbojet-engine. The flameholder (30) comprises a body (34) which extends radially into the primary flow. The body (34) is formed by a V-dihedral having two outer plates (35, 36) which intersect at a common ridge apex (37). An air tube (38) is mounted between the two outer plates (35, 36) and at least one fuel conduit (44, 45) is disposed to the rear of the air tube (38). The overall cross-section of the air tube (38) is approximately triangular and the air tube (38) includes a transverse downstream wall that is curved to define a trough (42) in which the fuel conduit (44, 45) is located. The air tube (38) includes orifices (41, 46) directed against the dihedral plates (35, 36) and the fuel conduit (44, 45) to cool them. The fuel conduit includes a nozzle injector (46) directed downstream towards the afterburner chamber (23).

Abstract: The invention relates to a combustion chamber containing a number of aerohanical injectors mounted in the end of the chamber that connects the upstream end of two annular walls and which are supplied with fuel permanently during operation. The injectors are arranged in two concentric rows around the axis of symmetry and in pairs in longitudinal planes passing through the axis of symmetry. The injectors of the two rows are more or less equidistant from the outlet of the chamber and have axes directed toward the outlet. A carefully considered distribution of the primary holes, dilution holes and the air flow allows the emissions of oxides of nitrogen to be reduced.

Abstract: A fuel injection system is disclosed for a gas turbine engine having a fuel injector issuing a primary fuel flow during all operating modes of the gas turbine engine and a secondary fuel flow when operating parameters of the gas turbine engine exceed predetermined values. The fuel injection system includes a first air swirler, a second air swirler located rearwardly of the first air swirler and a venturi having a wall with a converging-diverging inner wall surface forming a venturi throat, the venturi being located such that the wall separates first and second air flows issuing from the first and second air swirlers and such that the primary fuel flow emanating from the fuel injector in a conical configuration does not impact against the inner wall surface of the venturi.

Abstract: An annular combustion chamber is disclosed for use in a gas turbine engine, the combustion chamber having an axis of symmetry, an inner annular wall, an outer annular wall, and a forward end extending between the inner and outer wall to form boundaries for the combustion chamber. The forward end of the combustion chamber has an inner ring member extending about the axis of symmetry and an outer ring member extending about the axis of symmetry and radially spaced from the inner ring member, the inner and outer ring members forming inner and outer boundaries of an annular chamber that diverges in a rearward direction. The inner and outer ring members are interconnected by a plurality of circumferentially spaced apart spacers so as to form a plurality of arcuate openings between adjacent spacers.

Abstract: A device for actively controlling combustion instabilities and for decoking uel injectors comprises at least one detector for measuring pressure fluctuations in a combustion or afterburner chamber, means for processing the signal output by the detector and providing, in turn, a control voltage, and at least one piezoelectric device which is disposed in a hydraulic line including a fuel injector for the supply of fuel to the combustion or afterburner chamber and which is responsive to the control voltage to generate pulses in the flow of fuel from the outlet of the fuel injector.

Abstract: A combustion chamber, particularly for a turbomachine, has at least one generally axially extending wall provided with a plurality of through holes defining a multi-hole cooling system for the wall. The wall also has a plurality of dilution holes which affect locally the flow of burnt gases in the chamber, and the cooling through holes are oriented according to the local flow of burnt gases in the chamber. In particular the wall is subdivided into first zones, downstream of the dilution holes, in which the through holes are oriented substantially in countercurrent to the overall flow direction of the burnt gases in the chamber, second zones and third zones which are disposed on opposite sides of the first zones and in which the orientation of the through holes is inclined both axially and circumferentially, and a fourth zone covering the remainder of the wall and in which the through holes are inclined axially in the overall flow direction of the burnt gases.

Abstract: A method of preventing instabilities due to combustion in a multi-flow turbojet engine including an afterburner into which an air-fuel mixture is injected in proportions measured in richness terms, which includes the steps of detecting experimentally, when tuning the turbojet engine, the zones of vibrations due to afterburn as a function of the operating conditions of the engine and as a function of the afterburn operating region, and selecting operating points for regulating the fuel richness of each flow to enable the detected vibration zones to be avoided.