Fuel injection device

Abstract

Fuel injection device (25) (71) comprising a flow modification device (170) arranged to act on the flow rate and / or injection angle of simultaneously at least two flows (Fp, F1, F2, F3) selected from a purge air flow (Fp), a primary air flow (F1), a secondary air flow (F2) and a tertiary air flow (F3). Figure for abbreviation: Figure 3

Description

Title of the invention: TITLE OF THE INVENTION Fuel injection device technical field

[0001] 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. PREVIOUS STATE OF THE ART

[0002] 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 various states. 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.

[0003] 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 aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0006] As illustrated in [Fig. 1], an annular combustion chamber 10 in a turbomachine 1000 typically comprises two annular walls, respectively internal 12 and external 14, which define its boundaries and are connected upstream to an annular chamber bottom wall 16, and downstream respectively to an external casing 18 of the turbomachine and to an internal ferrule 20 connected to a diffuser 22 arranged upstream of the combustion chamber 10 and intended to diffuse compressed air from a turbomachine compressor (not visible in [Fig. 1]) into this chamber, in a well-known manner. The chamber bottom 16 generally has orifices regularly distributed around the axis of the chamber and in which air and fuel injection systems 24 are mounted, each intended 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 [Fig. 1] are of the central injector type 26. As shown more precisely in [Fig. 2], which is a larger-scale view of the injection system 24 shown in [Fig. 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 rotating parts 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, and designed to guide a portion of the fuel sprayed by the central injector 26 downstream by venturi effect and to spray this fuel at a lip 37, formed at the downstream end of said wall, in a well-known manner. In the example shown in [Fig. 2], the . Two air intake channels 29 and 30, along with 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 outer casing 18 of the combustion chamber ([Fig. 1]). 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 internally delimited by a frustoconical portion 46 of the annular wall 38 so as to present an opening facing radially outwards substantially in the shape of a bowl.Portion 46 has air injection holes 47 from space 53 into the primary zone 10a of the combustion chamber 10. In operation, fuel is injected into channel 29 by injector 26 and this fuel then meets the airflow flowing in channel 29, which promotes the atomization of this fuel, i.e. the spraying of this fuel into fine droplets to then meet the airflow flowing in channel 30.

[0007] The restart ceiling of a turbojet engine corresponds to 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 notably 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 that 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.

[0008] SUBJECT OF THE INVENTION

[0009] The invention aims to improve the general performance of a turbomachine and more particularly to improve its restart ceiling. Description of the invention

[0010] For this purpose, a fuel injection device is provided for mounting in a fuel injection system to inject fuel into of a combustion chamber. The injection system comprises a crankcase of revolution extending around a main axis and defining an injection volume. The crankcase 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 crankcase 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 injection orifices for a purge airflow. The first channel is supplied by a second series of injection orifices with the primary airflow, and the second channel is supplied by a third series of injection orifices with the secondary airflow.The crankcase also includes a substantially frustoconical portion intended to open into the combustion chamber and which includes a fourth series of orifices for injecting a tertiary airflow. According to the invention, the injection device includes a flow modification device arranged to act on the flow rate and / or injection angle of simultaneously at least two flows selected from the purge airflow, the primary airflow, the secondary airflow and the tertiary airflow.

[0011] This gives us a fuel injection device which allows us to modify the flow rates and directions of the air flows involved in the carburetion of the turbomachine and thus to be able to modify them according to the phases of flight or the expected performance.

[0012] According to other specific, non-exclusive and optional embodiments of the invention: - the flow modification device is mounted to rotate around the main axis so that the angular position of the flow modification device relative to the housing acts on the flow rate and / or injection angle of at least two flows simultaneously; - the flow modification device is arranged so that the angular position of the flow modification device relative to the casing allows simultaneous action 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 provided with at least a first row of first conduits and a second row of second conduits, the first and second conduits fluidically connecting the outer and inner faces, the ring being configured to selectively close, at least partially, at least a portion of the orifices from two series of orifices among the first, second, third and fourth series of orifices; - the first row of first conduits and / or the second row of second conduits includes conduits in the shape of a circular cylinder whose diameters are different; - the first row of first conduits and / or the second row of second conduits includes cylindrical conduits whose guide curve is defined by two semicircles of different radii connected by straight line segments; - the first row of first conduits and / or the second row of second conduits includes cylindrical conduits whose guiding curve is a quadrilateral; - the quadrilateral has one side extending in a plane orthogonal to the main axis and / or one side extending in a direction parallel to the main axis; - the first row of first ducts and / or the second row of second ducts comprises ducts in the shape of a straight cylinder. ; - the first row of first conduits and / or the second row of second conduits includes at least one cylindrical conduit whose generatrix extends in a direction including a non-zero tangential and / or axial component; - The injection device includes an actuator for the flow modification device which is controlled by pressure from a fuel circuit.

[0013] Other features and advantages of the invention will become apparent from the following description of a particular, non-limiting embodiment of the invention. Brief description of the drawings

[0014] Reference will be made to the attached figures, among which:

[0015] [Fig-1] [Fig.1] is a schematic cross-sectional representation of a system injection of the anterior artery;

[0016] [Fig.2] [Fig.2] is a partial schematic cross-sectional representation of the system of [Fig.1];

[0017] [Fig.3] [Fig.3] is a schematic half-section representation of an injection system according to a first embodiment of the invention;

[0018] [Fig.4] [Fig.4] is a schematic representation of a section of a flow modification device according to a first embodiment of the invention;

[0019] [Fig.5] [Fig.5] is a schematic detail representation of the flow modification device of [Fig.4];

[0020] [Fig.6] [Fig.6] is a schematic detail representation of the flow modification device according to a second embodiment of the invention;

[0021] [Fig.7] [Fig.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;

[0022] [Fig.8] [Fig.8] is a schematic representation of a first configuration of the flow modification device of [Fig.7];

[0023] [Fig.9] [Fig.9] is a schematic representation of a second configuration of the flow modification device of [Fig.7];

[0024] [Fig. 10] [Fig. 10] is a schematic representation of a second configuration of the flow modification device of [Fig. 7];

[0025] [Fig. 11] [Fig. 11] is a partial schematic detail representation of the injection device according to a fourth embodiment of the invention;

[0026] [Fig. 12] [Fig. 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.

[0027] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0028] As a preliminary matter, an axial direction is defined, as well as a radial direction that is orthogonal to the axial direction and a circumferential / tangential direction that is orthogonal to the axial and radial directions. The axial direction Ax is considered to be the direction of the central axis 28 of the injection system.

[0029] Elements identical or analogous to those previously described shall bear a numerical reference identical to that in the following description of a first embodiment of the invention.

[0030] As shown in [Fig. 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 27 extending around a main axis 28 and defining an injection volume 10a. The housing 27 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.

[0031] The housing 27 also has an internal wall of revolution 27.2 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 web 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 airflow Fh. The second channel 130 is supplied by a third series of orifices 163 for injecting the secondary airflow F2. The housing 27 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 airflow F3.

[0032] The injection device 25 comprises a ring 170 rotatably mounted about the main axis 28 relative to the housing 27. As shown in [Fig. 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 comprises 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 substantially corresponds to a portion of the geometry of an outer face 274 of the housing 27.

[0033] 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 mounted on the ring 170 such that there exists 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.

[0034] 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 of the second series of orifices 162, and / or of the third series of orifices 163, and / or of the fourth series of orifices 164.

[0035] Thus, the angular position of the ring 170 relative to the housing 27 allows simultaneous action on the flow rate of the purge air flow Fp, the primary air flow Fi, the secondary air flow F2 and the tertiary air flow F3.

[0036] 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 here supplied by a tap made on the injection circuit 70 and is thus controlled by a fuel pressure 71 which reigns in the injection circuit 70.

[0037] According to this first embodiment, and as shown in [Fig. 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 [Fig. 3], the 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 [Fig. 4], a generatrix 184.g of the conduit 184 extends in a direction dl84g which comprises 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.

[0038] Figure 6 represents a second embodiment in which the first row of first conduits 181 comprises straight circular cylindrical conduits, two of which have different diameters D181. 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.

[0039] According to a third embodiment shown in [Fig. 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 of diameter D181.2 and a second semicircle 181.3 of 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.

[0040] According to a fourth embodiment shown in Figures 11 and 12, the generatrix 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 The non-zero tangential component 184gt allows the tangential orientation of the tertiary flow F3 to be modified.

[0041] 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 action on an injection angle of the purge air flow Fp, the primary air flow Fi, the secondary air flow F2 and the tertiary air flow F3.

[0042] 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.

[0043] 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 for example orifices made in a radial web and which extend 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 piloted valves mounted in series or actuated shutters; - although here the conduits are in the form of a straight circular cylinder, the invention also applies to other types of conduits such as, for example, straight non-circular cylindrical conduits, which may have a square, elliptical or triangular guiding curve; - although here the conduits of the first row are in the form of straight circular cylinders of which two successive conduits are of different diameters, the invention also applies to other types of configurations in which the conduits are in the form of straight circular cylinders of which two have different diameters such as for example the conduits of the second row and / or the third row and / or the fourth row; - although here the conduits are in the form of a straight cylinder whose guide curves are rectangular, the invention also applies to other types of guide curves in the form of a quadrilateral such as, for example, guide curves in the form of a square, rhombus, parallelogram or any other shape.

[0044] Finally, a person skilled in the art understands that the terms "first conduits" and "second conduits" apply indifferently to a first conduit selected from the first row of first conduits, the second row of second conduits conduits, the third row of third conduits and the fourth row of fourth conduits, and 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 housing of revolution (27) extending about a main axis (28) and delimiting an injection volume (10a), the housing 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 housing (27) having an internal wall (27.2) of revolution which separates a first annular channel (129) for supplying a primary airflow (FJ) into the injection volume (10a) and a second annular channel (130) bringing a secondary airflow (F2) into the injection volume (10a), the veil (27.1) comprising a first series of orifices (161) for injecting a purge air stream (Fp), the first channel (129) being supplied by a second series of orifices (162) for injecting the primary air stream (FJ) and the second channel (130) being supplied by a third series of orifices (163) for injecting the secondary air stream (F2), the housing (27) also comprising a substantially frustoconical portion (27.3) intended to open into the combustion chamber (10) and which comprises a fourth series of orifices (164) for injecting a tertiary air stream (F3), the injection device (25) being characterized in that it comprises a flow modification device (170) arranged to act on the flow rate and / or injection angle of simultaneously at least two streams (Fp, Fi, F2, F3) selected from the purge air stream (Fp), the primary airflow (Fi), the secondary airflow (F2) and the tertiary airflow (F3).

2. A fuel injection device (25) according to claim 1, wherein the flow modification device (170) is rotatably mounted about the main axis (28) such that the angular position of the flow modification device (170) relative the casing (27) acts on the flow rate and / or an injection angle simultaneously on at least two flows (Fp, Fh F2, F3).

3. Fuel injection device (25) according to claim 2, wherein the flow modification device (170) is arranged so that the angular position of the flow modification device (170) relative to the crankcase allows simultaneous action on the flow rate and / or injection angle of the purge air flow (Fp) and the primary air flow (FJ) and the secondary air flow (F2) and the tertiary air flow (F3).

4. 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).

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

6. Fuel injection device (25) (71) according to claim 4, 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).

7. Fuel injection device (25) (71) according to claim 4, 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.

8. Fuel injection device (25) (71) according to claim 7, 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).

9. Fuel injection device (25) (71) according to any one of claims 5 to 8, 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.

10. Fuel injection device (25) (71) according to any one of claims 4 to 6, 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.

11. 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 pressure from a fuel circuit (41).

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