BENT COMBUSTION CHAMBER FROM A TURBINE ENGINE

Abstract

The invention relates to a turbine engine combustion chamber including: an outer annular housing; a flame tube (20) connected to the outer housing, said flame tube (20) including an inner annular wall (20b) and an outer annular wall (20a) that define a first radial inlet portion of the flame tube and a second axial outlet portion of the flame tube, the flame tube also including a chamber base (30) located at the inlet of the flame tube (20); and a fuel injection system (40) configured to inject fuel into the flame tube via the inlet of the flame tube. The injection system includes an injector axis (AA), parallel to the first portion, and an air manifold (40d) configured to move air towards twists in the injection system (40). The twists are arranged around an implantation axis parallel to the injector axis. The air manifold includes a circular portion around the injector axis. The circular portion, from which extends an opening, forms an air inlet of the manifold. The opening is configured to place the entering air flow in rotation about the implantation axis so that said air flow is supplied to the twists.

Claims

1. A combustion chamber of a turbine engine, comprising: an outer annular casing; a flame tube connected to the outer casing, said flame tube comprising an inner annular wall and an outer annular wall defining on the one hand a first radial portion at the inlet of the flame tube and on the other hand a second axial portion at the outlet of the flame tube, the flame tube further comprising a chamber base located at the inlet of the flame tube; a fuel injection system configured to inject fuel in the flame tube via the inlet of the flame tube, the injection system comprising an injector axis which is parallel to the first portion, and an air manifold configured to bring air towards twists of the injection system, the twists being disposed around an implantation axis which is parallel to the injector axis, the circular part from which extends an opening forming an air inlet of the manifold, the opening being configured to set the incoming air flow in rotation around the implantation axis so that it feeds the twists.

2. The combustion chamber according to claim 1, wherein the opening comprises a straight part which extends tangentially to the circular part and a divergent part extending from the circular part.

3. The combustion chamber according to claim 1, wherein the circular part has a constant radius around the injector axis.

4. The combustion chamber according to claim 1, wherein the circular part has an increasing radius around the injector axis.

5. The combustion chamber according to claim 1, wherein the opening has a general shape: circular, rectangular, profiled.

6. The combustion chamber according to claim 1, wherein the flame tube is connected to the our casing through said injection system in connection with the chamber base.

7. The combustion chamber according to claim 1, wherein the injections system has a main direction coaxial with a longitudinal axis Y along which the first portion extends.

8. The combustion chamber according to claim 1, wherein the first portion of the flame tube extends toward the second portion by forming a bend between the inlet and the outlet of the flame tube.

9. A turbine engine comprising a combustion chamber according to claim 1.

Description

PRESENTATION OF THE FIGURES

[0028] Other features, aims and advantages of the invention will be revealed by the description that follows, which is purely illustrative and not limiting, and which must be read with reference to the appended drawings in which, other than FIG. 1 already discussed,

[0029] FIG. 2 illustrates a section view of a combustion chamber;

[0030] FIG. 3 illustrates a perspective view of a combustion chamber;

[0031] FIG. 4 illustrates a detailed view of the connection of the combustion chamber according to a first embodiment;

[0032] FIG. 5 illustrates a detailed view of the combustion chamber according to a second embodiment;

[0033] FIGS. 6 and 7 illustrate a manifold of a first type of the combustion chamber according to a second embodiment;

[0034] FIGS. 8 and 9 illustrate a manifold of a second type of the combustion chamber according to the second embodiment.

[0035] In all the figures, similar elements carry identical reference symbols.

DETAILED DESCRIPTION OF THE INVENTION

[0036] FIGS. 2 and 3 illustrate views of a combustion chamber according to one embodiment.

[0037] The combustion chamber comprises an outer casing 10a to which a flame tube 20 is connected.

[0038] The flame tube 20 comprises an annular inner wall 20b and an annular outer wall 20a.

[0039] The annular inner and outer walls define, on the one hand, a first radial portion 201 around a radial axis Y of the combustion chamber and which extends radially with respect to a longitudinal axis XX of rotation of the turbine engine.

[0040] On the other hand, the annular inner and outer walls define a second axial portion 202 around a longitudinal axis X perpendicular to the radial axis Y and parallel to the longitudinal axis XX of rotation of the turbine engine.

[0041] As may be seen in FIGS. 2 and 3, the first portion 201 extends toward the second portion 202 by forming a bend between the inlet and the outlet of the flame tube.

[0042] Such a bend allows an effective aerodynamic connection with a high-pressure stage downstream of the gas flow (dotted arrow in FIG. 2).

[0043] In addition, this bent shape allows the axial use of space of the flame tube 20 to be reduced.

[0044] This has the following advantages. [0045] the mass of the engine is reduced: [0046] the shape of the flame tube allows a reduction in the length of the outer casing, which is often common with the high-pressure turbine downstream of the combustion chamber; [0047] a reduction in length for the equipmentductsnacelle and all the out-of-stream constituents; [0048] the structure of the chamber is simplified in particular by the fact that the flame tube is connected to the outer casing through the injector, which allows the elimination of the enclosures and the associated bolts. These parts are generally used on direct axial type chambers; [0049] the dynamic situation of the high-pressure rotor, located below the combustion chamber, is improved: [0050] this part is in fact a complex element of the turbine engine and must satisfy numerous dimensioning criteria. For turbine engines with small dimensions and with high performance requirements (in fuel consumption and emissions), it is tempting to position a high rotation speed: the difficulty then being to ensure acceptable stiffness and shaft dynamics. Thus, the bent shape given the flame tube allows to reduce the high-pressure shaft length (consisting of a high-pressure compressor upstream of the combustion chamber and the high-pressure turbine downstream of the combustion chamber); [0051] the interface with the high-pressure turbine is improved: [0052] in fact, the outlet of the flame tube is collinear with the design of DHP platforms: this allows to limit the number of lines of flow currents which would impact the wall (particularly on the inner shroud) and could potentially interfere with the cooling of these parts, the lifetime of which is critical [0053] the ignition plug may be positioned at different positions: at the chamber base and/or at a chamber corner and/or on the outer wall.

[0054] The combustion chamber also comprises a chamber base 30 which has the shape of a plate located at the inlet of the flame tube 20.

[0055] Attached to this chamber base 30 is an injection system 40 of a first type through which the flame tube 20 is connected to the outer casing 10a of the turbine engine.

[0056] In addition, the combustion chamber may possibly comprise a thermal shield 50 in the form of a plate attached to the chamber base 30 located in the flame tube 20. This thermal shield 50 is located at the inlet of the flame tube 20 and protects the injection system 40 from high temperatures greater than 2200 K which may occur in the flame tube 20.

[0057] Primary holes 202a, 202b are drilled in the inner and outer annular walls at the first portion 201 at the inlet of the flame tube.

[0058] In addition, dilution holes 203a, 203b are drilled in the inner and outer annular walls at the bent part of the flame tube 20 (see FIG. 3). The number of holes, their diameters and respective positions may vary depending on the application concerned.

[0059] Moreover, a diffuser 60 allows to bring air to the injection system 40 so as to cool it.

[0060] As may be seen in FIG. 4, the injection system 40 according to a first embodiment comprises an injector body 40a surrounding an injection pipe 40b through which the fuel as such is delivered into the flame tube 20. The injector body 40a is attached to the outer casing 10a by means of bolts 70 and attachment plates 80 (see FIG. 3).

[0061] The inner and outer annular walls are attached to the outer casing 10a by means of the injector body 40a, thus allowing the simplification of the bowl-chamber base connection and thus avoiding the use of a clearance compensation system.

[0062] A connection disk 40c topped with a cylinder 40d in which is inserted the body 40a of the injector is connected to the chamber base 30 wherein a recess 30a with the size of the connection disk has been provided.

[0063] The injector body 40a is in connection with the injection pipe 40b and the body 40a of the injection system 40 is inserted into the cylinder 40d on top of the connection disk 40c in such a manner that the injector body 40a (and therefore the injection pipe 40b) is movable with respect to the cylinder 40d. This allows compensation of the movements to which the flame tube 20 is subjected. There is therefore no need for complex compensation systems.

[0064] The injector body 40a comprises an air inlet 40e through which the air from the diffuser 60 is introduced. This air allows to supply the injection system 40 with air. The air inlet 40e has, with no limitation, the shape of an oval recess formed in the body 40a of the injector. It will therefore be understood that other shapes may be contemplated.

[0065] Alternatively, as may be seen in FIG. 5, the combustion chamber according to a second embodiment differs from the first embodiment by the structure of an injection system 40 of a second type.

[0066] The flame tube 20 involved in this second embodiment is identical with that previously described. Moreover, the injection system 40 is attached to the chamber base 30, the flame tube 20 being connected to the outer casing 10a of the turbine engine by means of the injection system 40.

[0067] The injection system 40 in this second embodiment comprises an injector body 40a on top of a circular connection structure 40c comprising at least one connection disk. The connection structure 40c is inserted into the chamber base 30 in which a recess with the size of the circular connection structure has been provided. The manifold 40d is secured to the injector body 40a.

[0068] As in the first embodiment, the inner and outer annular walls are attached to the outer casing 10a by means of the injector body 40a, thus allowing simplification of the bowl-chamber base connection and thus avoiding the use of a clearance compensation system.

[0069] The injector body 40a surrounds an injection pipe 40b (along the injector axis AA) through which the fuel as such is brought into the flame tube 20. The injector axis AA is congruent with the radial axis Y so as to be parallel to the first radial portion 201 of the flame tube 20.

[0070] In order to improve the efficiency of the air supply of the injection system by means of twists applied to the pipe 40b, an air manifold 40d tops the injection pipe 40b. The twists are formed by bladings positioned around an implantation axis parallel to the injector axis AA. The implantation axis around which the twists are located and the injector axis AA may be congruent.

[0071] This manifold is arranged in proximity to the diffuser 60 without being connected to the latter (in which case vibrations could damage the structure). In addition, the manifold is separated physically from the diffuser because of dilation speeds which are different.

[0072] As illustrated in FIGS. 6 and 7, the air manifold 40d may be in the axis AA of the injection system and comprises a circular part 41 surrounding the injection pipe 40b with a constant radius.

[0073] This circular part 41 has identical dimensions to the injector body 40a. From this circular part 41 extends an opening 42 through which air from the diffuser 60 is introduced. The opening 42 has a straight part 43 tangent to the circular part 41 and a divergent part 44 from the circular part 41 (or convergent from the air inlet). Of course, the manifold may have other shapes. The circular shape of this circular part 41 allows facilitating the rotation of the air flow around the implantation axis of the twists which is congruent with the injector axis AA in the exemplary embodiment illustrated in FIGS. 6 and 7.

[0074] Alternatively, as illustrated in FIGS. 8 and 9, the air manifold 40d may be offset with respect to the axis AA of the injector. In these figures, it is offset to the left but may of course be offset to the right of the axis AA of the injector.

[0075] For this reason, the manifold comprises a circular part 41 having an increasing radius around the injection pipe (non-constant radius around the injection pipe). Advantageously, the circular part 41 extends first along a constant radius over a first portion, and an increasing radius beyond (volute type shape). And from this circular part 41 extends the opening 42 having a straight part tangent to the circular part and a divergent part 44 from the circular part.

[0076] The opening 42 may have several shapes: rectangular, circular or profiled.

[0077] Consequently, air from the diffuser enters the injection system through the opening 42, which thanks to its shape allows a general rotary motion to be imposed on the air flow to allow the feeding of the twists 40e.

[0078] In addition, depending on the shape and the dimensions given to the opening 42, the latter may avoid that water entering the engine in the case of water or hail ingestion enters the manifold and is then injected into the flame tube, particularly in the primary combustion zone. For this reason, the outer radius of the opening 42 may be judiciously adapted so as not to capture water (liquid or vapor) which is located preferentially on the outside radii of the centrifugal wheel and the axial diffuser.