AIR INTAKE RING FOR A TURBOMACHINE COMBUSTION CHAMBER INJECTION SYSTEM AND METHOD OF ATOMIZING FUEL IN AN INJECTION SYSTEM COMPRISING SAID AIR INTAKE RING

Abstract

A system for improving fuel-air mixing inside an injection system of a turbomachine combustion chamber. An air intake ring has an annular deflection wall, or venturi, having an internal profile provided with a discontinuity inducing an increase in the radius (φ) of the internal profile downstream of the discontinuity. A method of atomizing fuel includes separating fuel trickling over the internal profile of the annular deflection wall from the internal profile at the level of the discontinuity so as to form droplets within a flow of air coming from an upstream air circulation space of the air intake ring.

Claims

1-8. (canceled)

9. An air intake ring for an injection system of a combustion chamber of a turbomachine, having an axis of revolution, and comprising an annular separation wall that divides the air intake ring into an upstream air circulation space and a downstream air circulation space, and that extends radially inwards into an annular deflection wall having an internal profile with a convergent-divergent shape, wherein the internal profile of the annular deflection wall has a discontinuity that induces an increase in the radius of the internal profile downstream of said discontinuity.

10. The air intake ring according to claim 9, wherein said discontinuity is formed at the level of a neck of the internal profile of the annular deflection wall.

11. The air intake ring according to claim 9, wherein said discontinuity defines a shoulder extending orthogonally to said axis of revolution of the air intake ring.

12. The air intake ring according to claim 9, wherein each of the upstream and downstream air circulation spaces are passed through by fins allowing for the gyration of the air about said axis of revolution of the air intake ring.

13. An injection system for a combustion chamber of a turbomachine, comprising a fuel injector head in addition to an air intake ring according to claim 9, wherein the fuel injector head is configured to spray fuel over an annular region of the internal profile of the annular deflection wall, and wherein said discontinuity is formed downstream of an upstream end of said annular region of the internal profile.

14. A combustion chamber for a turbomachine, comprising at least one injection system according to claim 13.

15. A turbomachine, in particular for an aircraft, comprising at least one combustion chamber according to claim 14.

16. A method of atomizing fuel in an injection system according to claim 13, said injection system being associated with a turbomachine combustion chamber, wherein fuel originating from the injector head trickles over the internal profile of the annular deflection wall, and separates from said internal profile at the level of the discontinuity of the latter, so as to form droplets within a flow of air coming from the upstream air circulation space of the air intake ring and circulating along the internal profile of the annular deflection wall.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0036] The invention will be better understood, and other features, advantages and characteristics of the invention will appear upon reading the following description provided as a non-limiting example with reference to the appended figures, in which:

[0037] FIG. 1, previously described, is a partial diagrammatic view of an axial cross-section of a known type of turbomachine;

[0038] FIG. 2, previously described, is a partial diagrammatic view of an axial cross-section of a combustion chamber of the turbomachine in FIG. 1;

[0039] FIG. 3, previously described, is a partial diagrammatic half-view of an axial cross-section of an injection system with which the combustion chamber in FIG. 2 is equipped;

[0040] FIG. 4 is a view similar to that of FIG. 3, illustrating an injection system comprising an air intake ring according to one preferred embodiment of the invention;

[0041] FIG. 5 is a more large-scale view of a portion of FIG. 4.

[0042] In all of these figures, identical references may represent identical or similar elements.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0043] FIGS. 4 and 5 illustrate an injection system 42 that is similar on the whole to the injection system in FIGS. 1 to 3, however that is different in that it comprises an air intake ring 56 according to one preferred embodiment of the invention.

[0044] One feature of said air intake ring 56 is that the internal profile 68 of the annular deflection wall 66 is provided with a discontinuity 90 that induces an increase in the radius φ of the internal profile downstream of said discontinuity 90.

[0045] Therefore, a downstream portion of the internal profile 68 is set back, i.e. offset radially outwards relative to an upstream portion of said internal profile 68.

[0046] The discontinuity 90 induces the presence of an edge 92 at the level of the downstream end of the upstream portion of the internal profile.

[0047] Moreover, the discontinuity 90 is formed downstream of an upstream end 93 of the annular region 83 of the internal profile 68, over which trickles the fuel film 82.

[0048] During operation, the fuel forming the fuel film 82 trickling over the internal profile 68 tends to separate at the level of said edge 92, driven to such by the air flow 76 circulating along the internal profile 68.

[0049] The separation of the fuel into droplets, or atomisation, therefore takes place further upstream than with the known types of air intake ring. The droplets therefore have a larger volume for evaporation before penetrating the combustion chamber.

[0050] Moreover, the discontinuity 90 creates a recirculation area downstream thereof and induces turbulence, which favours the mixing of the fuel with the air, and which makes thickening the flame front possible

[0051] In a general manner, the invention therefore improves the mixing of the air and fuel, and thus improves the combustion efficiency.

[0052] In one preferred example, as shown in FIG. 4, the discontinuity 90 is formed at the level of the neck 70 of the internal profile 68.

[0053] Therefore, the separation of the fuel into droplets occurs at the place at which the speed of the air flow 76 circulating along the internal profile 68 is the highest. This minimises the size of the fuel droplets generated.

[0054] Preferably, the discontinuity defines a shoulder 94 extending orthogonally to the axis of revolution 44 of the air intake ring 56 (FIG. 5).

[0055] For the purpose of illustration, the injection system 42 equips a combustion chamber similar to the combustion chamber in FIG. 2, within a turbomachine similar to the turbomachine in FIG. 1.

[0056] The injection system therefore allows for the implementation of a fuel atomisation method, wherein fuel originating from the injector head 52 trickles over the internal profile 68 of the annular deflection wall 66, and separates from said internal profile 68 at the level of the discontinuity 90 of the latter, so as to form droplets within the flow of air 76 coming from the upstream air circulation space 62 of the air intake ring 56 and circulating along the internal profile 68.

[0057] In a general manner, the invention allows for the reduction of the lean extinction proportions and CO/CH emissions.