TURBINE ENGINE COMBUSTION ASSEMBLY

Abstract

The invention relates to a turbine engine combustion assembly (20), which includes: an annular flame tube (21) including a front wall (23), a rear wall (24) and a bottom (22) arranged facing an engine shaft (30); an injection wheel (41) rotated by said engine shaft (30), partially projecting into the bottom (22) of the flame tube (21) and configured such as to spray fuel into the flame tube by centrifugation; and at least one injector (35), capable of depositing a film of fuel on said injection wheel (41), said combustion assembly being characterised in that said injector (35) is arranged so as to pass through said upstream area of the front wall (23) or the rear wall (24) of the flame tube (21), so that the injection opening thereof (37) opens into said tube (21), opposite the portion (43) of said injection wheel (41) which is located inside said flame tube (21).

Claims

1. A turbine engine combustion assembly comprising: an annular flame tube, comprising a front wall equipped with an upstream zone oriented upstream of the combustion assembly, a rear wall provided with an upstream zone oriented upstream of the combustion assembly and a bottom positioned opposite an engine shaft, an injection wheel driven in rotation by said engine shaft coaxial with the longitudinal axis X-X′ of the combustion assembly, said injection wheel protruding partially into the flame tube through its bottom and being configured to centrifugally atomize fuel in the flame tube, at least one injector capable of depositing a film of fuel on said injection wheel, this combustion assembly being characterized in that said injector is positioned through said upstream zone of the front wall or through said upstream zone of the rear wall of the flame tube and in such a manner that its injection opening leads inside this tube opposite the portion of said injection wheel which is located in said flame tube.

2. The combustion assembly according to claim 1, wherein said injector is positioned through the upstream zone of the front wall of the flame tube, in that said injection wheel is curved at its perimeter upstream of the combustion assembly, so as to have an annular edge, in that the annular edge is bored with several radial injection holes and in that said injector leads into the flame tube opposite the front face of the annular peripheral portion of said injection wheel which is located in the flame tube.

3. The combustion assembly according to claim 1, wherein said injector is positioned through the upstream zone of the rear wall of the flame tube, in that said injection wheel is curved at its perimeter downstream of the combustion assembly, so as to have an annular edge, in that the annular edge is bored with several radial injection holes and in that said injector leads into the flame tube opposite the rear face of the annular peripheral portion of said injection wheel which is located in the flame tube.

4. The combustion assembly according to claim 1, wherein said injection wheel is solid and has an annular fuel receiving radial face which protrudes into the flame tube and in that the injector leads into the flame tube opposite this annular fuel receiving face.

5. The combustion assembly according to claim 4, wherein the injector is oriented so as to project fuel tangentially onto said fuel receiving face of the injection wheel.

6. The combustion assembly according to claim 4, the fuel receiving face of the injection wheel forms an angle α with the axis of the injection opening of the injector, this angle (α) being comprised between 90° and 180°.

7. The combustion assembly according to claim 4, wherein the axis of the injection opening of the injector extends in a plane (P1) which includes the axis of the injection wheel and which is perpendicular to the median plane (P) of the wheel perpendicular to the axis of the injection wheel.

8. The combustion assembly according to claim 4, wherein the axis of the injection opening of the injector is not perpendicular to the median plane (P) of the wheel perpendicular to the axis of the injection wheel.

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

Description

PRESENTATION OF THE FIGURES

[0045] Other features and advantages of the invention will appear from the description that will now be made of it, with reference to the appended drawings which represent, indicatively but without limitation, different possible embodiments of it.

[0046] In these drawings:

[0047] FIG. 1 is a longitudinal section view of a combustion assembly according to one embodiment of the prior art,

[0048] FIGS. 2 and 3 are schematic views, in longitudinal section, of two embodiments of a turbine engine combustion assembly conforming to the invention,

[0049] FIG. 4 is a schematic view of the combustion assembly, taken along a section plane embodied in line IV-IV of FIG. 3.

DETAILED DESCRIPTION

[0050] A first embodiment of the invention will now be described in connection with FIG. 2.

[0051] This FIG. 2 is a schematic of a combustion assembly 20 which is simplified with relation to that of FIG. 1 because it shows only the flame tube and the injection assembly.

[0052] The flame tube 21 comprises a bottom 22 (or inner side of the flame tube), a front wall 23 and a rear wall 24. The bottom 22 connects the front wall 23 and the rear wall 24.

[0053] As for the previous combustion assembly 1, the flame tube 21 is annular and extends around the longitudinal axis X-X′ of the combustion assembly 20.

[0054] The bottom 22 is bored with an opening 25 allowing passage of a portion of the injection wheel 26 into the interior of the flame tube 21. In other words, the injection wheel 26 protrudes partially into the bottom of the flame tube 21.

[0055] The front wall 23 has an upstream zone 230, oriented upstream of the combustion assembly and of the turbine engine (to the left in FIG. 2), bored with a plurality of air intake openings 27, opposite the primary combustion zone 28 of the flame tube.

[0056] Likewise, the rear wall 24 has an upstream zone 240, oriented upstream of the combustion assembly and the turbine engine, bored with a plurality of air intake openings 29 opposite the primary combustion zone 28 of the flame tube.

[0057] The injection wheel 26 is driven in rotation by the engine shaft 30, coaxial with the longitudinal axis X-X′. It has a front face 31, oriented upstream of the combustion assembly and an opposite rear face 32 oriented downstream.

[0058] This injection wheel 26 is curved at its perimeter so as to define a peripheral annular edge 33 bored, preferably at regular intervals, with holes 34 oriented radially with respect to the longitudinal axis X-X′ of the combustion assembly 20. These holes 34 can be orifices or slots.

[0059] In comparison with the injection wheel 7 of the prior art (see FIG. 1), it will be noted that here the injection wheel 26 penetrates further inside the flame tube 21 because not only is its annular peripheral edge 33 complete inside, but also an annular peripheral portion 260 of the disk that constitutes the wheel 26. This annular portion 260 is located in the extension of the edge 33.

[0060] The inner face of the annular edge 33 is thus located at a distance D1 from the bottom 22 of the flame tube 21 which is, for its part, opposite the engine shaft 30.

[0061] The combustion assembly also comprises one or more injectors 35, of which only one is visible in FIG. 2.

[0062] This injector 35 is connected to a fuel feed tube 36, itself connected to a fuel source not shown in the figure.

[0063] The injector 35 has an injection opening 37.

[0064] Unlike the prior art, the injector 35 is positioned so as to pass through the front wall 23 of the flame tube 21, preferably its upstream zone 230, through which the air intake openings 27 are provided. In addition, this injector 35 is positioned so that its injection opening 37 leads to the interior of the flame tube 21.

[0065] To this end, it will be noted that the distance Dl is sufficient to allow passage of the fuel jet leaving the injection end 37 of the injector 35.

[0066] The injection operation is as follows. The fuel leaving the injector 35 leaves through the injection opening 37 and is projected against the front face 31 of the portion 260 of the injection wheel 26, where it forms a fuel film F.

[0067] Under the influence of centrifugal force due to the rotation of the injection wheel 26, the fuel film is displaced toward the perimeter of the wheel and passes through the holes 34, which has the effect, in contact with the air surrounding the wheel, of pulverizing or atomizing the fuel into very fine droplets G, distributed in the interior of the flame tube 21.

[0068] The fact that the injector 31 is positioned through the front wall 23 of the flame tube facilitates its disassembly. Preferably, its configuration will be adapted so as to provide for its extraction through this front wall 23.

[0069] Also advantageously, it will be noted that the injection wheel 26 has a smaller diameter than that of the prior art shown in FIG. 1, because the bottom 22 of the flame tube 21 can be positioned nearer the engine shaft 30. It will be noted in this regard that FIGS. 1 and 2 are not shown at the same scale.

[0070] The injection wheel 26 having a smaller diameter, its mass is smaller than that of a wheel of the prior art and its mechanical strength is also improved as a result.

[0071] Another embodiment of the invention will now be described in connection with FIG. 3. The same elements bear the same numerical references and will therefore not be described in detail again.

[0072] The injection wheel bears the reference number 41. It is driven in rotation by the engine shaft 30.

[0073] It differs from the injection wheel 26 in that it is solid, that is it is not bored with injection holes 34. Its peripheral edge 42 is flared so as to define a circular radial face 43, preferably flat, for receiving the fuel film F.

[0074] The injector 35 is positioned so that its injection opening 37 is opposite this face 43.

[0075] The axis of the injection opening 37 forms an angle α (alpha) with the fuel receiving face 43. This angle α is advantageously comprised between 90° and 180°. When it is 180°, fuel injection occurs tangentially to the face 43.

[0076] It will also be noted that, in this case, considering the median plane P of the wheel (41) to be perpendicular to the axis of the engine shaft 30 driving this wheel, then the axis of the injection opening 37 of an injector 35 extends in a plane P1 which is both perpendicular to P and including the axis of the engine shaft 30. In FIG. 3, the plane P1 corresponds to the plane of the paper of the figure and in FIG. 4, the plane P1 is shown by a dotted straight line.

[0077] However, it is also possible to orient the axis of the injection opening 37 so that it is not perpendicular to P. In other words, this axis then protrudes or separates from the plane P1 corresponding to the plane of FIG. 3. In FIG. 4, this axis is referred to as X1-X′1.

[0078] In this embodiment, it will be noted that the injector 35 is advantageously inserted less deeply into the flame tube 21 than in the embodiment of FIG. 2, because it is not necessary for its injection opening to reach the zone located below the annular edge 33 of the injection wheel. It is sufficient that the injector allows the projection of fuel onto the face 43. The disassembly of the injection 35 is thereby facilitated.

[0079] As before, the fuel film F is subjected to the centrifugal force generated by the wheel 41 and is atomized in the form of fuel droplets G.

[0080] This embodiment of the invention makes it possible to have an injection wheel 41 which has a structure with great simplicity and good mechanical endurance because it is not bored with through holes. Its diameter is also smaller than in the prior art because the bottom 22 of the flame tube 21 can be brought closer to the engine shaft 30. Finally, combustion occurs substantially on only one side of the injection wheel 41, to the left in FIG. 3 here.

[0081] Moreover, it will be noted that variant embodiments of the invention are possible. In particular, the injector 35 can be positioned through the rear wall 24 of the flame tube 21, preferably through its upstream zone 240.

[0082] In this case, and when the injection wheel 26 is made according to the embodiment of FIG. 2, its annular edge 33 is turned downstream of the combustion assembly 20 and fuel injection occurs on the rear face 32 of the wheel.

[0083] When the injector is positioned through the rear wall 24 and the injection wheel 41 conforms to the embodiment of FIG. 3, then its receiving face 43 is oriented toward the rear wall 24.

[0084] The different possible inclinations of the axis of the injection opening 37 and the different values of the angle α previously described also apply to this variant embodiment.

[0085] Finally, according to another variant embodiment, it is possible to provide that the flame tube 21 is made in several portions, assembled using a flange 50 which facilitates disassembly.