Fuel injection device

Abstract

Disclosed is a device (25) for injecting fuel (71), comprising a flow modification device (170) arranged to act simultaneously on the flow rate and / or an injection angle of at least two flows (Fp, F1, F2, F3) chosen from a purge air flow (Fp), a primary air flow (F1), a secondary air flow (F2) and a tertiary air flow (F3).

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION

[0003] Fuel injection device

[0004] TECHNICAL FIELD

[0005] The present invention relates to the field of combustion chambers in turbomachinery, particularly aircraft turbomachinery, and more specifically concerns air and fuel injection systems in these combustion chambers. The invention more precisely relates to central injector injection systems delivering a variable fuel flow rate.

[0006] PREVIOUS STATE OF THE ART

[0007] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by different countries. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0008] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain less energy-intensive and more environmentally friendly aeronautical components and products, whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0009] Consequently, the Applicant is constantly working to reduce its negative climate impact by employing environmentally sound methods and processes for development and manufacturing that minimize greenhouse gas emissions to the absolute minimum possible, thereby reducing the environmental footprint of its activities. This sustained research and development work focuses on new generations of aircraft engines, aircraft weight reduction (particularly through the use of lighter materials and onboard equipment), the development of electric propulsion technologies, and, as essential complements to technological progress, aviation biofuels.

[0010] As illustrated in Figure 1, an annular combustion chamber 10 in a turbomachine 1000 typically comprises two annular walls, an inner wall 12 and an outer wall 14, which define its boundaries and are connected upstream to an annular wall at the bottom of the chamber 16, and downstream respectively to an external casing 18 of the turbomachine and to an internal ring 20 connected to a diffuser 22 arranged upstream of the combustion chamber 10 and designed to diffuse compressed air from a turbomachine compressor (not visible in Figure 1) into this chamber, in a well-known manner. The bottom of the chamber 16 generally has orifices regularly distributed around the axis of the chamber, in which air and fuel injection systems 24 are mounted, each designed to produce a flame in the combustion chamber 10.Such a combustion chamber 10 is usually divided into an upstream zone 10a, called the primary zone or injection volume, dedicated to the combustion of flames from the injection systems 24 at the bottom 16 of the chamber, and a downstream zone 10b, called the dilution zone, dedicated to the cooling and dilution of the combustion gases in fresh air from orifices formed in the annular walls 12 and 14 delimiting the combustion chamber. The injection systems 24 of the combustion chamber 10 shown in Figure 1 are of the central injector type 26. As shown more clearly in Figure 2, which is a larger-scale view of the injection system 24 shown in Figure 1, the central fuel injector 26 is formed by a nozzle opening onto a central axis 28 of the system, which essentially constitutes an axis of symmetry for the parts of revolution composing the injection system 24.This central injector 26 is usually associated with two air intake channels, including an internal channel 29 into which the central injector 26 opens so that the fuel sprayed by this injector can be immediately mixed with the air admitted into the internal channel 29, and an external annular channel 30 which opens downstream into the injection system to allow for further enrichment of the air-fuel mixture. The two aforementioned air intake channels 29 and 30 are generally traversed by oblique fins 32 and 34 designed to impart a rotary motion to the airflow passing through them around the central axis of the injection system 24 to promote homogenization of the air-fuel mixture within the injection system.Each of the two aforementioned air intake channels 29 and 30 is commonly called a spiral (internal or primary spiral for channel 29 and external or secondary spiral for channel 30), and is generally delimited externally by an annular wall 36, respectively 38, with a convergent-divergent internal profile, sometimes called a venturi, designed to guide a portion of the fuel sprayed by the central injector 26 downstream by venturi effect and to spray this fuel onto a lip 37, formed at the downstream end of said wall, in a well-known manner. In the example shown in Figure 2, the two air intake channels 29 and 30, as well as the annular walls 36 and 38 delimiting them, extend substantially along the axis 28 of the injection system. The central injector 26 is supplied by a conduit 40 partially housed in an arm 41 carried by the external casing 18 of the combustion chamber (figure l).The injection system 24 also includes a peripheral annular channel 52, which is delimited internally by the annular wall 38 and externally by a wall 56. The wall 56 carries means 58 for mounting the injection system 24 in the bottom 16 of the combustion chamber. In the example shown in Figures 1 and 2, the annular air intake space 53 has a frustoconical shape and is delimited internally by a frustoconical portion 46 of the annular wall 38 so as to present a radially outwardly facing, substantially bowl-shaped opening. The portion 46 has air injection holes 47 from the space 53 into the primary zone 10a of the combustion chamber 10.During operation, fuel is injected into channel 29 by injector 26 and this fuel then encounters the airflow circulating in channel 29, which promotes the atomization of this fuel, that is to say the spraying of this fuel in the form of fine droplets to then encounter the airflow circulating in channel 30.

[0011] The restart ceiling of a turbojet engine is the maximum altitude at which an aircraft engine can be restarted in the event of an in-flight engine failure. The restart ceiling thus determines the aircraft's ability to maintain powered operation at high altitudes. Factors such as atmospheric pressure, ambient temperature, and oxygen availability influence the engine's ability to restart at higher altitudes. The restart ceiling for an injection system such as injection system 24 is specifically linked to the airflow rates and the direction of the primary and secondary airflows passing through the primary 29 and secondary 30 spinners, respectively. However, the flow rate parameters used to optimize the restart ceiling are generally different from those that promote turbomachine efficiency, and even different from those that reduce pollutant emissions (particularly unburned fuel).The compromises found on these flow rates and orientations generally favor the environmental performance of the turbomachine at the expense of the re-ignition ceiling.

[0012] SUBJECT OF THE INVENTION

[0013] The invention aims to improve the overall performance of a turbomachine and more particularly to improve its restart ceiling.

[0014] DESCRIPTION OF THE INVENTION

[0015] For this purpose, a fuel injection device is provided for mounting in a fuel injection system to inject fuel into a combustion chamber. The injection device comprises a housing of revolution extending around a main axis and defining an injection volume. The housing has a web that receives a central fuel injector connected to an injection circuit to inject fuel into the injection volume in an axial direction. The housing has an internal wall of revolution that separates a first annular channel for supplying a primary airflow into the injection volume from a second annular channel for supplying a secondary airflow into the injection volume. The web includes a first series of bleed air injection orifices.The first channel is supplied by a second series of primary airflow injection ports, and the second channel is supplied by a third series of secondary airflow injection ports. The housing also includes a substantially frustoconical portion for opening into the combustion chamber, which includes a fourth series of tertiary airflow injection ports. According to the invention, the injection device comprises a flow modification device arranged to act on the flow rate and / or injection angle of at least two flows simultaneously, selected from the purge airflow, the primary airflow, the secondary airflow, and the tertiary airflow.

[0016] This results in a fuel injection system that allows the flow rates and directions of the airflows involved in the turbomachine's fueling to be modified according to the flight phases or expected performance.

[0017] According to other particular, non-exclusive and optional embodiments of the invention: the flow modification device is mounted to rotate about the main axis so that the angular position of the flow modification device relative to the housing acts on the flow rate and / or an injection angle of simultaneously the at least two flows; the flow modification device is arranged so that the angular position of the flow modification device relative to the housing allows to act simultaneously on the flow rate and / or an injection angle of the purge air flow and the primary air flow and the secondary air flow and the tertiary air flow;the flow modification device comprises a ring delimited by an outer face and an inner face and which is provided with at least a first row of first conduits and a second row of second conduits, the first conduits and the second conduits fluidically connecting the outer face and the inner face, the ring being configured to selectively close, at least partially, at least a portion of the orifices of two sets of orifices among the first, second, third and fourth sets of orifices; the first row of first conduits and / or the second row of second conduits comprises conduits in the shape of a circular cylinder having different diameters; the first row of first conduits and / or the second row of second conduits comprises conduits in the shape of a cylinder whose guiding curve is defined by two semicircles of different radii connected by straight line segments;The first row of first ducts and / or the second row of second ducts comprises cylindrical ducts whose directrix is ​​a quadrilateral; the quadrilateral has one side extending in a plane orthogonal to the principal axis and / or one side extending in a direction parallel to the principal axis; the first row of first ducts and / or the second row of second ducts comprises ducts in the shape of a right cylinder; the first row of first ducts and / or the second row of second ducts comprises at least one cylindrical duct whose generatrix extends in a direction including a non-zero tangential and / or axial component;

[0018] The injection device includes a flow modification device actuator which is controlled by pressure from a fuel circuit.

[0019] Other features and advantages of the invention will become apparent from the following description of a particular, non-limiting embodiment of the invention.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Reference will be made to the attached figures, among which:

[0022] [Fig. 1] Figure 1 is a schematic cross-sectional representation of a prior art injection system;

[0023] [Fig. 2] Figure 2 is a partial schematic cross-sectional representation of the system of Figure 1; [Fig. 3] Figure 3 is a schematic half-cross-sectional representation of an injection system according to a first embodiment of the invention;

[0024] [Fig. 4] Figure 4 is a schematic representation of a section of a flow modification device according to a first embodiment of the invention;

[0025] [Fig. 5] Figure 5 is a schematic detail representation of the flow modification device in Figure 4;

[0026] [Fig. 6] Figure 6 is a schematic detail representation of the flow modification device according to a second embodiment of the invention;

[0027] [Fig. 7] Figure 7 is a schematic detail view of a guide curve of a conduit of the flow modification device according to a third embodiment of the invention;

[0028] [Fig. 8] Figure 8 is a schematic representation of a first configuration of the flow modification device of Figure 7;

[0029] [Fig. 9] Figure 9 is a schematic representation of a second configuration of the flow modification device of Figure 7;

[0030] [Fig. 10] Figure 10 is a schematic representation of a second configuration of the flow modification device of Figure 7;

[0031] [Fig. 11] Figure 11 is a partial schematic detail representation of the injection device according to a fourth embodiment of the invention;

[0032] [Fig. 12] Figure 12 is a partial schematic cross-sectional representation along a plane XII-XII of the injection device according to a fourth embodiment of the invention.

[0033] DETAILED DESCRIPTION OF SPECIFIC METHODS OF IMPLEMENTATION

[0034] As a preliminary matter, an axial direction, a radial direction orthogonal to the axial direction, and a circumferential / tangential direction orthogonal to the axial and radial directions are defined. The axial direction Ax is considered to be the direction of the central axis 28 of the injection system. Elements identical or analogous to those previously described will bear the same numerical reference in the following description of a first embodiment of the invention.

[0035] As shown in Figure 3, the injection system 24 according to a first embodiment of the invention comprises a multipoint fuel injection device 25. The injection device 25 includes a housing of revolution Tl extending around a main axis 28 and defining an injection volume 10a. The housing Tl has a transverse web 27.1 which receives a central fuel injector 26 connected to an injection circuit 70 for injecting fuel 71 into the injection volume 10a in an axial direction.

[0036] The crankcase Tl also has an internal wall of revolution Tl, which separates a first annular channel 129 for supplying a primary air flow Fi into the injection volume 10a and a second annular channel 130 for supplying a secondary air flow F2 into the injection volume 10a. The shell 27.1 includes a first series of orifices 161 for injecting a purge air flow Fp. The first channel 129 is supplied by a second series of orifices 162 for injecting the primary air flow Fi. The second channel 130 is supplied by a third series of orifices 163 for injecting the secondary air flow F2. The crankcase Tl also includes a substantially frustoconical portion 27.3 intended to open into the combustion chamber 10 and which includes a fourth series of orifices 164 for injecting a tertiary air flow F3.

[0037] The injection device 25 includes a ring 170 mounted for rotation about the main axis 28 relative to the housing 27. As seen in figure 4, the ring 170 is a solid of revolution about the axis 28 and is delimited by an outer face 171 and an inner face 172. The ring 170 includes a first substantially radial portion 173 which is connected by a second substantially axial portion 174 to a third substantially radial portion 175. A fourth, substantially radial portion 176 connects portion 175 to a frustoconical portion 177. Overall, the inner face 172 has a geometry that corresponds substantially to a portion of the geometry of an outer face 27.4 of the housing 27. The ring 170 is provided with a first row of first conduits 181, a second row of second conduits 182, a third row of third conduits 183 and a fourth row of conduits 184.The conduits 181, 182, 183 and 184 fluidly connect the outer face 171 and the inner face 172. The conduits 181, 182, 183 and 184 are axially and radially implanted on the ring 170 so that there is at least one angular position of the ring 170 relative to the housing 27 in which: at least one conduit 181 faces at least one orifice 161; and / or at least one conduit 182 faces at least one orifice 162; and / or at least one conduit 183 faces at least one orifice 163; and / or at least one conduit 184 faces at least one orifice 164.

[0038] In other words, the angular and radial position of the conduits 181, respectively 182, 183 and 184, relative to each other on the ring 170 allows to selectively close, at least partially, at least a part of the orifices of the first series of orifices 161, and / or the second series of orifices 162, and / or the third series of orifices 163, and / or the fourth series of orifices 164.

[0039] Thus, the angular position of the ring 170 relative to the housing 27 allows simultaneous control of the purge air flow rate F p , of the primary airflow Fi, of the secondary airflow F2 and of the tertiary airflow F3.

[0040] The ring 170 includes a finger 190 that projects radially from the portion 174 and whose end 191 is engaged in a groove 195 of a yoke 196 to form a grooved cam. A cylinder 200 actuates a translation of the yoke 196 to cause a rotation of the ring 170 relative to the housing 27. The cylinder 200 is supplied here by a connection made on the injection circuit 70 and is thus controlled by a fuel pressure 71 present in the injection circuit 70.

[0041] According to this first embodiment, and as shown in Figure 5, the first row of first conduits 181 comprises straight circular cylindrical conduits whose diameters D181 of two angularly successive conduits 181 are different. As shown in Figure 3, conduits 182 and 183 are straight cylinders whose respective direction curves 182.1 and 183.1 are rectangles having a longer side extending in a plane orthogonal to the axis 28 and a shorter side extending in a direction parallel to the axis 28. As shown in Figure 4, a generatrix 184.g of conduit 184 extends in a direction dl84g which includes a radial component 184gr and a non-zero axial component 184.ga. The generators 182g and 183g extend respectively along purely radial directions dl82g and dl83g (zero axial component) and a generator 181g of the conduit 181 extends along a purely axial direction dl81g.

[0042] Figure 6 illustrates a second embodiment in which the first row of first conduits 181 comprises straight, circular cylindrical conduits with diameters D181 of two different diameters. According to this second embodiment, there is an alternation of two conduits 181 of the same diameter followed by a conduit 181 of a different diameter. Similar arrangements (successive circular cylindrical conduits of different diameters) can also be applied to the second conduits 182 and / or the third conduits 183 and / or the fourth conduits 184.

[0043] According to a third embodiment shown in Figures 7 to 10, the first row of first conduits 181 comprises cylindrical conduits whose directing curve 181.1 is defined by two semicircles of different radii connected by straight line segments. More precisely, the directing curve 181.1 comprises a first semicircle 181.2 with diameter D181.2 and a second semicircle 181.3 with diameter D181.3 smaller than D181.2. An upper straight line segment 181.4 and a lower straight line segment 181.5 connect the semicircles 182.2 and 182.3. Figures 8 to 10 show different relative positions of a conduit 181 of the first row and an orifice 161 of the first series of orifices. The flow area 181.6 resulting from the position of the conduit 181 relative to the orifice 161 is hatched. This type of direction curve can advantageously be applied to other conduits belonging to other rows of conduits.According to a fourth embodiment shown in Figures 11 and 12, the generator 184g of the conduit 184 extends along a direction dl84 comprising a non-zero tangential component 184gt and a non-zero radial component 184gr. The non-zero tangential component 184gt allows modification of the tangential orientation of the tertiary flow F3.

[0044] Similar arrangements (cylinder-shaped conduits whose generatrices include a non-zero tangential component) can also be applied to the first conduits 181 and / or the second conduits 182 and / or the third conduits 183. In this way, the position of the ring 170 relative to the housing 27 allows for adjustment of the injection angle of the purge air flow F p , the primary airflow Fi, the secondary airflow F2 and the tertiary airflow F3.

[0045] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0046] In particular, although here the first orifices are made in a transverse web, the invention also applies to first orifices made in a differently oriented web, such as orifices made in a radial web and extending over a tangential surface of the housing; although here the injection device has a ring, the invention also applies to other types of flow modification devices, such as a plurality of pilot-operated valves mounted in series or actuated obturators; although here the conduits are in the form of a straight circular cylinder, the invention also applies to other types of conduits, such as straight non-circular cylindrical conduits, which may have a square, elliptical, or triangular guide curve;Although here the ducts of the first row are in the form of right circular cylinders where two successive ducts have different diameters, the invention also applies to other types of configurations in which the ducts are in the form of right circular cylinders where two have different diameters, such as the ducts of the second row and / or the third row and / or the fourth row; although here the ducts are in the form of right cylinders whose guide curves are rectangular, the invention also applies to other types of guide curves in the form of a quadrilateral, such as guide curves in the form of a square, rhombus, parallelogram or any other shape.

[0047] Finally, a person skilled in the art understands that the terms "first conduits" and "second conduits" apply equally to a first conduit selected from the first row of first conduits, the second row of second conduits, the third row of third conduits, and the fourth row of fourth conduits, and to a second conduit selected from the rows to which the first conduit does not belong. The same applies to the orifices of the first, second, third, and fourth series of orifices.

Claims

DEMANDS 1. Fuel injection device (25) (71) for mounting in a fuel injection system (24) for injecting fuel (71) into a combustion chamber (10), the injection device (25) comprising a casing of revolution (27) extending around a main axis (28) and defining an injection volume (10a), the casing having a web (27.1) which receives a central fuel injector (26) (71) connected to an injection circuit (70) for injecting fuel (71) into the injection volume (10a) in an axial direction (Ax), the casing (27) having an internal wall (27.2) of revolution which separates a first annular channel (129) for supplying a primary airflow (Fi) into the injection volume (10a) and a second annular channel (130) for supplying a secondary airflow (F2) in the injection volume (10a), the veil (27.1) comprising a first series of orifices (161) for injecting a purge airflow (F p), the first channel (129) being supplied by a second series of orifices (162) for injecting the primary airflow (Fi) and the second channel (130) being supplied by a third series of orifices (163) for injecting the secondary airflow (F2), the casing (27) also comprising a substantially frustoconical portion (27.3) intended to open into the combustion chamber (10) and which includes a fourth series of orifices (164) for injecting a tertiary airflow (F3), the injection device (25) being characterized in that it comprises a flow modification device (170) arranged so as to act on the flow rate and / or an injection angle of at least two flows simultaneously (F p , Fi, F2, F3) selected from the purge airflow (F p), the primary airflow (Fi), the secondary airflow (F2) and the tertiary airflow (F3), wherein the flow modification device (170) is mounted to rotate about the main axis (28) such that the angular position of the flow modification device (170) relative to the housing (27) acts on the flow rate and / or injection angle of simultaneously the at least two flows (F p , Fi, F2, F3).

2. Fuel injection device (25) according to claim 1, wherein the flow modification device (170) is arranged such that the angular position of the flow modification device (170) relative to the crankcase allows simultaneous control of the flow rate and / or the injection angle of the purge air flow (F p ) and the primary airflow (Fi) and the secondary airflow (F2) and the tertiary airflow (F3).

3. Fuel injection device (25) (71) according to claim 2 or 3, wherein the flow modification device (170) comprises a ring (170) delimited by an outer face (171) and an inner face (172) and which is provided with at least a first row of first conduits (181) and a second row of second conduits (182), the first conduits (181) and the second conduits (182) fluidly connecting the outer face (171) and the inner face (172), the ring (170) being configured to selectively close, at least partially, at least a portion of the orifices of two sets of orifices (161, 162, 163, 164) among the first, second, third and fourth set of orifices (161, 162, 163, 164).

4. Fuel injection device (25) (71) according to claim 3, wherein the first row of first conduits (181) and / or the second row of second conduits (182) comprise conduits in the shape of circular cylinders having different diameters.

5. Fuel injection device (25) (71) according to claim 3, wherein the first row of first conduits (181) and / or the second row of second conduits (182) comprises cylindrical conduits whose guiding curve (181.1) is defined by two semicircles (181.2, 181.3) of different radii connected by straight segments (181.4, 181.5).

6. Fuel injection device (25) (71) according to claim 3, wherein the first row of first conduits (181) and / or the second row of second conduits (183) comprises cylindrical conduits whose guiding curve (183.1) is a quadrilateral.

7. Fuel injection device (25) (71) according to claim 6, wherein the quadrilateral has one side extending in a plane orthogonal to the main axis (28) and / or one side extending in a direction parallel to the main axis (28).

8. Fuel injection device (25) (71) according to any one of claims 5 to 7, wherein the first row of first conduits (181) and / or the second row of second conduits (182) comprises conduits in the shape of a straight cylinder.

9. Fuel injection device (25) (71) according to any one of claims 3 to 5, wherein the first row of first conduits (181) and / or the second row of second conduits (184) comprises at least one cylindrical conduit (184) of which a generatrix (184g) extends in a direction comprising a non-zero tangential (184gt) and / or axial (184ga) component.

10. Fuel injection device (25) (71) according to any one of the preceding claims, comprising an actuator (200) of the flow modification device (170) which is controlled by a pressure from a fuel circuit (41).

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