EP3449185B1 - Turbomachine injection system comprising an aerodynamic deflector at its inlet and an air intake swirler - Google Patents

Description

TECHNICAL AREA

The present invention relates to an air intake swirler intended to form part of an air and fuel injection system in a turbomachine, as well as an injection system for a turbomachine comprising at least one such swirler. air intake, and a turbomachine for an aircraft comprising such an injection system.

STATE OF THE PRIOR ART

The document WO 2010/081940 A1 discloses an injection system for injecting a mixture of air and fuel into a combustion chamber of a turbomachine according to the preamble of claim 1. The figure 1 attached illustrates a turbomachine 10 for an aircraft of a known type, for example a bypass turbojet, generally comprising a fan 12 intended for the suction of an air flow dividing downstream of the fan into a flow primary supplying a core of the turbomachine and a secondary flow bypassing this core. The heart of the turbomachine generally comprises a low pressure compressor 14, a high pressure compressor 16, a combustion chamber 18, a high pressure turbine 20 and a low pressure turbine 22. The turbomachine is streamlined by a nacelle 24 surrounding the flow space 26 of the secondary flow. The rotors of the turbomachine are mounted to rotate about a longitudinal axis 28 of the turbomachine.

The figure 2 represents the combustion chamber 18 of the turbomachine of the figure 1 . Conventionally, this combustion chamber, which is of the annular type, comprises two coaxial annular walls, respectively radially internal 32 and radially external 34, which extend from upstream to downstream, in the direction 36 of flow. the primary flow of gas in the turbomachine, around the axis of the combustion chamber which merges with the axis 28 of the turbomachine. These internal 32 and external 34 annular walls are interconnected at their upstream end by an annular chamber bottom wall 40 which extends substantially radially around the axis 28. This annular chamber bottom wall 40 is equipped with injection systems 42 distributed around the axis 28 to allow, each, the injection of a pre-mixture of air and fuel centered along a respective injection axis 44. Throughout the present description, the axial and radial directions are defined with reference to the injection axis 44. In addition, a transverse plane is a plane orthogonal to the injection axis 44.

The combustion chamber generally comprises an annular protective shroud 45 extending opposite an upstream face of the chamber bottom wall 40 and comprising orifices for passage of injectors and for air intake.

In operation, a part 46 of an air flow 48 coming from a diffuser 49 and coming from the compressor 16 feeds the injection systems 42 while another part 50 of this air flow bypasses the combustion chamber. by flowing downstream along the coaxial walls 32 and 34 of this chamber and in particular allows the supply of air inlet openings provided within these walls 32 and 34.

As shown in the figure 3 , each injection system 42 generally comprises a sleeve 52, sometimes referred to as a "sliding bushing", in which a fuel injection nose 54 forming the end of an injector arm 55 is mounted, as well as one or more air intake swirls 56, 58, and finally a bowl 60, sometimes referred to as a “mixing bowl” or “pre-vaporization bowl”, which essentially takes the form of an annular wall having a flared tapered portion downstream. These elements are centered with respect to the injection axis 44.

The air intake tendrils 56, 58 (also called " swirlers " according to the English terminology) are separated from each other by an annular wall which extends radially inwards to form a annular internal deflection wall 62, also called “venturi”, having an internal profile of convergent-divergent shape.

The injection systems 42 have an essential role in the operation of the combustion chamber. Their efficiency depends in particular on the quality of their air supply which comes directly from the diffuser.

In this regard, the air intake augers 56, 58 contribute to the mixing of air and fuel. Each spinner 56, 58 thus comprises an annular row of inclined fins so as to set the air flow 64 in rotation and thus improve the atomization of the fuel jet coming from the fuel injection nose 54. In particular, some of this fuel trickles in liquid form on the internal surface of the venturi 62 and is sheared by the swirling air at the downstream end of the venturi 62.

DISCLOSURE OF THE INVENTION

The object of the invention is to improve the performance of the injection systems of turbomachines.

It provides for this purpose an injection system for injecting a mixture of air and fuel into a combustion chamber of a turbomachine with an air intake swirl comprising an upstream wall and a downstream wall both of revolution around 'an axis of the air intake swirler, and fins distributed around the axis and connecting the upstream wall to the downstream wall so as to delimit between the upstream and downstream walls air inlet channels having each has an inlet arranged on a radially outer side and an outlet arranged on a radially inner side.

According to the invention, the air intake swirler further comprises an aerodynamic deflector which extends the downstream wall radially outwards to a free end of the aerodynamic deflector, and which has a concavity facing upstream of so that the aerodynamic deflector extends radially opposite the respective inlets of the air inlet channels.

In general, the aerodynamic deflector makes it possible to channel the air flow intended to enter the air inlet channels and therefore to limit the pressure losses of this air flow as much as possible.

This results in an improvement in the general performance of a turbomachine combustion chamber equipped with an injection system comprising such an air intake swirler, in particular in terms of the overall thermodynamic cycle.

In a first preferred embodiment of the invention, the aerodynamic deflector extends continuously over 360 degrees around the axis, from the downstream wall to the free end of the aerodynamic deflector.

In a second preferred embodiment of the invention, the aerodynamic deflector comprises recesses formed in the free end of the aerodynamic deflector so as to define between them teeth respectively arranged opposite the respective inlets of the air inlet channels. .

Preferably, the upstream and downstream walls extend substantially orthogonally to the axis.

Furthermore, the aerodynamic deflector is preferably shaped so that at each point of the free end of the aerodynamic deflector, a circumferential plane tangent to a radially inner edge of the free end is substantially parallel to the axis of the twist air intake.

According to the invention, the injection system for injecting a mixture of air and fuel into a combustion chamber of a turbomachine, also comprises a sleeve for centering an injector, a bowl, and at least a first spinner. Air intake of the type described above arranged axially between the sleeve and the bowl.

According to the invention, the injection system further comprises a second air intake swirler also of the type described above, arranged axially between the first air intake swirler and the bowl.

In this case, the downstream wall of the first air intake swirler is the upstream wall of the second air intake swirler.

In addition, the injection system advantageously comprises an annular internal deflection wall having an internal profile of converging-diverging shape, which extends the downstream wall of the first air intake swirl towards the interior of the injection system. .

Preferably, the respective free ends of the respective aerodynamic deflectors of the first and second air intake swirlers extend substantially in the same transverse plane.

In this case, the upstream wall of the first air intake swirler advantageously extends in the same transverse plane.

As a variant, the respective free ends of the respective aerodynamic deflectors of the first and second air intake swirlers can be offset with respect to each other in the direction of the axis of the air intake swirler. .

According to the invention, at least one of the respective aerodynamic deflectors of the first and second air intake swirlers is shaped so that the radial extent of the air intake section of the intake swirler d The corresponding air varies around the axis of the air intake swirl.

The invention also relates to a turbomachine for an aircraft, comprising a combustion chamber and at least one injection system of the type described above for supplying the combustion chamber with a mixture of air and fuel.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1, déjà décrite, est une vue schématique en section axiale d'une turbomachine d'un type connu ;
• la figure 2, déjà décrite, est une demi-vue schématique en section axiale d'une chambre de combustion de la turbomachine de la figure 1 ;
• la figure 3, déjà décrite, est une vue schématique en section axiale d'un système d'injection de la chambre de combustion de la figure 2 ;
• la figure 4 est une demi-vue schématique en section axiale d'un système d'injection qui ne fait pas partie de l'invention ;
• la figure 5 est une vue schématique partielle en perspective et en section axiale du système d'injection de la figure 4 ;
• les figures 6 et 7 sont des vue schématiques, respectivement en perspective et de face, d'un système d'injection qui ne fait pas partie de l'invention ;
• les figures 8 à 11 sont des vue schématiques en perspective de systèmes d'injection selon l'invention.

The invention will be better understood, and other details, advantages and characteristics thereof will appear on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

• the figure 1 , already described, is a schematic view in axial section of a turbomachine of a known type;
• the figure 2 , already described, is a schematic half-view in axial section of a combustion chamber of the turbomachine of the figure 1 ;
• the figure 3 , already described, is a schematic view in axial section of an injection system of the combustion chamber of the figure 2 ;
• the figure 4 is a schematic half-view in axial section of an injection system which does not form part of the invention;
• the figure 5 is a partial schematic view in perspective and in axial section of the injection system of the figure 4 ;
• the figures 6 and 7 are schematic views, respectively in perspective and from the front, of an injection system which does not form part of the invention;
• the figures 8 to 11 are schematic perspective views of injection systems according to the invention.

In all of these figures, identical references can designate identical or similar elements.

DETAILED PRESENTATION OF PREFERRED EMBODIMENTS

The figures 4 and 5 illustrate an injection system 70 similar to the injection system 42 of the figure 2 described above but comprising two air intake swirls 100, 200. The injection system 70 is intended to equip an aircraft turbomachine of the same type as the turbomachine of the figure 1 described above, or any other type of turbomachine.

The injection system 70 thus comprises a bush 52 intended to receive a fuel injection nozzle, the air intake swirls 100, 200, and a bowl 60. The air intake swirls 100, 200 are intended for the injection of a swirling air flow into two internal annular spaces of the injection system separated from each other by an annular internal deflection wall 62 having an internal profile of convergent-divergent shape, also called “venturi”, as explained above in relation to the injection system 42 of known type.

The first air intake swirl 100, also called an "internal swirl", comprises an upstream wall 102 and a downstream wall 104 which are both of revolution about an axis of the swirler which merges with the axis. injection 44 of the injection system. The first air intake swirl 100 further comprises fins 106 distributed around the axis 44 and connecting the upstream wall 102 to the downstream wall 104 so as to define between the upstream and downstream walls air inlet channels 108. Each air inlet channel 108 has an inlet 110 arranged on a radially outer side and an outlet 112 arranged on a radially inner side. More precisely, each inlet 110 is delimited between respective radially outer ends of two consecutive fins 106 which delimit the corresponding air inlet channel 108. Similarly, each outlet 112 is delimited between respective radially internal ends of two consecutive fins 106 which delimit the corresponding air inlet channel 108.

According to this example, the first air intake swirler 100 further comprises an aerodynamic deflector 120 which extends the downstream wall 104 radially outwards to a free end 122 of the aerodynamic deflector 120. The latter has a turned concavity. upstream. The aerodynamic deflector 120 thus extends radially opposite the respective inlets 110 of the air inlet channels 108. The free end 122 of the aerodynamic deflector 120 is therefore oriented generally in the upstream direction and delimits a section of air inlet of the first air inlet swirl 100.

In general, the aerodynamic deflector 120 thus makes it possible to channel the air flow F1 entering the air inlet channels 108 and therefore to limit the pressure losses of this air flow as much as possible.

In the system shown on figures 4 and 5 , the aerodynamic deflector 120 extends continuously over 360 degrees around the axis 44, from the downstream wall 104 to the free end 122 of the aerodynamic deflector 120.

In the example illustrated, the upstream 102 and downstream 104 walls of the first air intake swirler 100 extend orthogonally to the axis 44. The swirler is therefore of the radial type and thus has optimum compactness in the direction. axial.

As a variant, the upstream 102 and downstream 104 walls can be inclined relative to the axis 44, without departing from the scope of the invention.

In addition, in the example illustrated, the aerodynamic deflector 120 has a curved shape from the downstream wall 104 and up to the free end 122.

The aerodynamic deflector 120 can advantageously be manufactured by means of an additive manufacturing process, for example of the selective laser melting (SLM) type.

As a variant, the aerodynamic deflector 120 may have one or more curved axial sections and one or more cylindrical or frustoconical axial sections arranged axially end-to-end, without departing from the scope of the invention.

As a further variant, the aerodynamic deflector 120 may consist of a succession of axial sections of frustoconical shape, having respective apex angles that are all the smaller as the axial section considered is away from the downstream wall 104. In other words, the aerodynamic deflector 120 can have a segmented curvature instead of a continuous curvature, without departing from the scope of the invention.

Furthermore, in the example illustrated, the aerodynamic deflector 120 is shaped so that at each point of its free end 122, a circumferential plane P1 tangent to a radially inner edge 124 of the free end 122 is parallel to the axis 44 of the first air intake swirl 100.

In preferred embodiments of the invention, the air intake section of the first air intake swirl 100 is greater than or equal to three times the sum of the respective passage sections of the inlet channels d. air 108 from the first 100 air intake spin.

According to the invention, at least one of the respective aerodynamic deflectors (120,220) of the first and second air intake swirls (100,200) is shaped so that the radial extent (S1, S2) of the inlet section d The air from the corresponding air intake swirl varies around the axis (44). As a variant, the first aerodynamic deflector 120 may have an irregular shape around the axis 44 so as to adapt the radial extent S1 of the air inlet section to the pressure irregularities of the air flow 46 coming from the diffuser. 49 of the turbomachine, as will appear more clearly in what follows.

The second air intake swirl 200, which is arranged axially between the first air intake swirl 100 and the bowl 60, has a configuration similar to that of the first air intake swirl 100.

In particular, the second air intake swirl 200, also called an “external swirl”, comprises an upstream wall 202, which is the downstream wall 104 of the first air intake swirl 100, and a downstream wall 204 The two walls 202, 204 are of revolution about the axis of the swirler 200 which merges with the injection axis 44 of the injection system. The second air intake swirler 200 further comprises fins 206 distributed around the axis 44 and connecting the upstream wall 202 to the downstream wall 204 so as to delimit between the upstream and downstream walls of the inlet channels d. air 208. Each air inlet channel 208 has an inlet 210 arranged on a radially outer side and an outlet 212 arranged on a radially inner side. More precisely, each inlet 210 is delimited between respective radially outer ends of two consecutive fins 206 which delimit the corresponding air inlet channel 208. Similarly, each outlet 212 is delimited between respective radially internal ends of two consecutive fins 206 which delimit the corresponding air inlet channel 208.

In addition, the second air intake swirler 200 comprises an aerodynamic deflector 220 which extends the downstream wall 204 radially outward to a free end 222 of the aerodynamic deflector 220 oriented generally in the upstream direction and delimiting an air inlet section of the second air inlet swirl 200.

The aerodynamic deflector 220 has characteristics similar to those of the aerodynamic deflector 120 of the first air intake swirl 100 described above, and thus makes it possible to channel the air flow F2 entering the inlet channels of air 208.

In particular, a circumferential plane P2 tangent to a radially inner edge 224 of the free end 222 is parallel to the axis 44 of the second air intake swirl 200 ( figure 4 ).

In the example illustrated, the respective free ends 122, 222 of the respective aerodynamic deflectors 120, 220 of the first and second air intake swirlers 100, 200 extend substantially in the same transverse plane P3, in which extends also the upstream wall 102 of the first air intake swirl 100. Thus, the air intake sections delimited respectively by the aerodynamic deflectors 120 and 220 are defined substantially in the transverse plane P3.

Furthermore, the annular internal deflection wall 62 extends in the extension of the downstream wall 104 of the first air intake swirl 100 towards the interior of the injection system 70.

The figures 6 and 7 illustrate an injection system 70A generally similar to the injection system 70 described above, but in which the first and second air intake swirls 100A, 200A differ from the swirls 100, 200 described above, because that each of their respective aerodynamic deflectors 120A, 220A has recesses 126A, 226A formed in its free end 122A, 222A. These recesses 126A, 226A define between them teeth 128A, 228A respectively arranged facing the respective inlets 110, 210 of the air inlet channels 108, 208.

The teeth 128A of the aerodynamic deflector 120A of the first air intake swirl 100A are advantageously offset angularly with respect to the teeth 228A of the aerodynamic deflector 220A of the second air intake swirl 200A, so that each tooth 128A or arranged axially facing a corresponding recess 226A.

The recesses 126A of the aerodynamic deflector 120A of the first air intake swirl 100A thus allow additional air to pass in the direction of the second air intake swirl 200A.

As a variant, an injection system according to the invention may comprise a first air intake swirler in accordance with the second embodiment described above and a second air intake swirler in accordance with the first embodiment described. above, or vice versa.

The figure 8 illustrates an injection system 70B generally similar to the injection system 70 described above, but in which the aerodynamic deflector 220B of the second air intake swirl 200B is shaped so that the radial extent S2 of the air inlet section of said air intake swirl 200B varies around the axis 44.

In the example shown on figure 8 , the aerodynamic deflector 220B is in particular shaped so that its free end 222B is circular in shape and is eccentric with respect to the axis 44. The free end 222B is for example eccentric from the axis 44 in a direction oriented radially. outwards in relation to axis 28 of the combustion chamber (visible on the figure 2 ).

The radial extent S2 preferably takes a minimum value S2min equal to half of a nominal value corresponding to the radial extent that an equivalent section but of constant radial extent would have (as in the figures 4 and 5 ). In addition, the radial extent S2 preferably takes a maximum value S2max equal to three times the nominal value.

As a variant, the variability of the radial extent S2 of the air inlet section can be obtained by a non-axisymmetric shape of the aerodynamic deflector 220B, for example an eccentric oval shape.

As a variant or in a complementary manner, the aerodynamic deflector of the first air intake swirler can adopt a configuration such that the radial extent S1 of the air inlet section of the first air intake swirler varies around axis 44.

In general, the variability of the radial extent of the air inlet section of at least one of the air inlet swirlers makes it possible to optimize the homogeneity of the air supply of the air inlet. this spin having regard to various design parameters of the turbomachine, including in particular the possible heterogeneity of the flow at the outlet of compressor 16, the wake induced by the injector arm 55 in the air flow supplying the system d injection 70B, and the influence of the protective annular fairing 45 on the aforementioned air flow.

Other variants make it possible to optimize the air supply to the air intake augers according to such parameters, as shown in the figures 9 to 11 .

The figures 9 and 10 respectively illustrate injection systems 70C and 70D generally similar to the injection system 70 described above, but in which the respective free ends of the respective aerodynamic deflectors of the first and second air intake swirlers are offset one by one with respect to the other in the direction of axis 44.

Thus, in the embodiment of the figure 9 , the aerodynamic deflector 120C of the first air intake swirl 100C extends upstream beyond the free end 222 of the aerodynamic deflector 220 of the second air intake swirl 200.

Conversely, in the embodiment of the figure 10 , the aerodynamic baffle 220D of the second air intake twist 200D extends upstream beyond the free end 122 of the aerodynamic baffle 120 of the first air intake twist 100.

Finally, the figure 11 illustrates a 70E injection system similar to that of the figure 10 , except in that the aerodynamic deflector 220E of the second air intake swirl 200E has an oval or oblong free end 222E, extending for example from an annular portion of circular section 223E of the deflector.

In the example illustrated, the major axis 230E of the free end 222E is oriented in a circumferential direction defined with respect to the axis 28 of the combustion chamber (visible on the figure 2 ).

The shape of the free end 222E provides variability in the radial extent of the air inlet section of the second air inlet swirl 200E around axis 44, similarly to what has been described with reference to the figure 8 .

Claims (12)

1. An injection system (70; 70A; 70B; 70C; 70D; 70E) for injecting an air and fuel mixture in a turbomachine combustion chamber, comprising a sleeve (52) for centring an injector, a bowl (60), a first air intake swirler (100; 100A; 100C) axially arranged between the sleeve (52) and the bowl (60), and a second air intake swirler (200; 200A; 200B; 200D; 200E) axially arranged between the first air intake swirler (100; 100A; 100C) and the bowl (60), each of the air intake swirlers comprising an upstream wall (102, 202) and a downstream wall (104, 204) both of revolution about an axis (44) of the air intake swirler, and fins (106, 206) distributed about the axis (44) and connecting the upstream wall to the downstream wall so as to delimit between the downstream and upstream walls air inlet channels (108, 208) each having an inlet (110, 210) arranged on a radially outer side and an outlet (112, 212) arranged on a radially inner side, wherein the downstream wall (104) of the first air intake swirler (100; 100A; 100C) is the upstream wall (202) of the second air intake swirler (200; 200A; 200B; 200D; 200E), characterised in that each of the air intake swirlers further includes a respective aerodynamic deflector (120, 220; 120A, 220A; 120, 220B; 120C, 220; 120, 220D; 120, 220E) which is an outwardly radial extension of the downstream wall (104, 204) of the corresponding air intake swirler and is terminated with a free end (122, 222; 122A, 222A; 122, 222B; 122, 222E), wherein each respective aerodynamic deflector has a concavity pointing upstream such that the aerodynamic deflector extends radially facing the respective inlets (110, 210) of the air inlet channels of the corresponding air intake swirler, wherein at least one of the respective aerodynamic deflectors (220B; 220E) of the first and second air intake swirlers is shaped such that the radial extent (S2) of the air inlet section of the corresponding air intake swirler (200B; 200E) varies about the axis (44).
2. The injection system according to claim 1, wherein the aerodynamic deflector (120, 220; 120, 220B; 120C , 220; 120, 220D; 120, 220E) of at least one of the first and second air intake swirlers (100, 200; 100, 200B; 100C, 200; 100, 200D; 100, 200E) continuously extends over 360 degrees about the axis (44), from the downstream wall (104, 204) to the free end (122, 222; 122, 222B; 122, 222E) of the aerodynamic deflector.
3. The injection system according to claim 1, wherein the aerodynamic deflector (120A, 220A) of at least one of the first and second air intake swirlers (100A, 200A) includes recesses (126A, 226A) formed in the free end (122A, 222A) of the aerodynamic deflector so as to delimit between them teeth (128A, 228A) respectively arranged facing the respective inlets (110, 210) of the air inlet channels of the corresponding air intake swirler (100A, 200A).
4. The injection system according to any of claims 1 to 3, wherein the upstream (102, 202) and downstream (104, 204) walls of each of the first and second air intake swirlers (100, 200; 100A, 200A; 100, 200B; 100C, 200; 100, 200D; 100, 200E) substantially extend orthogonally to the axis (44).
5. The injection system according to any of claims 1 to 4, wherein the aerodynamic deflector (120, 220; 120A, 220A; 120, 220B; 120C, 220; 120, 220D; 120, 220E) of each of the first and second air intake swirlers (100, 200; 100A, 200A; 100, 200B; 100C, 200; 100, 200D; 100, 200E) is shaped such that at each point of the free end (122, 222) of the aerodynamic deflector, a circumferential plane (P1, P2) tangent to a radially inner edge (124, 224) of the free end is substantially parallel to the axis (44).
6. The injection system according to any of claims 1 to 5, further comprising an inner deflection annular wall (62) having an inner profile with a convergent-divergent shape, which is an extension of the downstream wall (104) of the first air intake swirler inwardly of the injection system.
7. The injection system according to any of claims 1 to 6, wherein the respective free ends (122, 222; 122A, 222A; 122, 222B) of the respective aerodynamic deflectors (120, 220; 120A, 220A; 120, 220B) of the first and second air intake swirlers (100, 200; 100A, 200A; 100, 200B) substantially extend in a same transverse plane (P3).
8. The injection system according to claim 7, wherein the upstream wall (102) of the first air intake swirler (100; 100A) extends in the same transverse plane (P3).
9. The injection system according to any of claims 1 to 6, wherein the respective free ends (122, 222) of the respective aerodynamic deflectors (120C, 220; 120, 220D) of the first and second air intake swirlers (100C, 200; 100, 200D) are offset with respect to each other along the direction of the axis (44).
10. The injection system according to any of claims 1 to 9, wherein said aerodynamic deflector (220B; 220E), which is shaped such that the radial extent (S2) of the air inlet section of the corresponding air intake swirler (200B; 200E) varies about the axis (44), is shaped so that its free end (222B; 222E) is off-centred from the axis 44.
11. The injection system according to any of claims 1 to 10, wherein said aerodynamic deflector (220B; 220E), which is shaped such that the radial extent (S2) of the air inlet section of the corresponding air intake swirler (200B; 200E) varies about the axis (44), has a non-axisymmetric shape.
12. An aircraft turbomachine, comprising a combustion chamber and at least one injection system (70, 70A) according to any of claims 1 to 11 for supplying the combustion chamber with an air and fuel mixture.

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