INJECTOR FOR A HIGH-PRESSURE TURBINE

Description

FIELD OF THE INVENTION

[0001] The present invention relates to the general field of ventilation of a high-pressure turbine of a twin-spool turbomachine, such as an aircraft turbojet. More specifically, the invention relates to an injector for a high-pressure turbine. STATE OF THE ART

[0002] A twin-spool turbomachine includes in particular a high-pressure turbine which is positioned at the outlet of a combustion chamber to recover energy from a flow of combustion gases coming from the combustion chamber and to drive in rotation, thanks to this recovery, a high-pressure compressor of the turbomachine arranged upstream of the combustion chamber and supplying the latter with pressurized air.

[0003] Typically, the high-pressure turbine comprises a rotor disc arranged at the outlet of the combustion chamber and on which are mounted turbine blades driven in rotation by the flow of gas ejected by this combustion chamber.

[0004] Due to the high temperatures reached by the combustion gases, the rotor disc and the turbine blades it carries are subjected to significant thermal stresses that can cause expansion. To limit the negative impact of these thermal stresses on the life of the turbine blades, the latter are equipped with internal cooling circuits that include ducts filled with ventilation air taken from the bottom of the combustion chamber.

[0005] This ventilation air is generally brought into an annular cavity by ventilation air injectors distributed circumferentially around the longitudinal axis of the turbomachine. The injectors are connected to an annular bypass space which extends around the combustion chamber, this annular space making it possible to convey ventilation air coming from the bottom of the compressor towards the turbine of the turbomachine, the compressor being located upstream of the combustion chamber and supplying it with pressurized air for the combustion of the gases. The ventilation air leaving the injectors enters the cavity by passing through orifices formed in a sealing flange arranged upstream of the rotor disk. The cavity communicates with the internal cooling circuits arranged inside the turbine blades.Reference may be made to publications FR 2,841,591 and FR 2,937,371 which describe examples of such high-pressure turbine architecture.

[0006] Generally, the injectors are axial (i.e. the air circulates substantially parallel to an axis of rotation of the turbomachine) and consist of either a crown of independent holes inclined at a fixed angle, or a row of static blades.

[0007] This architecture has the advantage of drawing low power from the rotor and not causing too much increase in temperature in the turbine.

[0008] However, axial injectors have the disadvantage of causing poor control of the seals located near the injector and do not guarantee good control of the air flow or good distribution of ventilation.

[0009] Injectors comprising an annular crown provided with a plurality of air ejection channels are already known from documents EP 3 228 816, DE 10 2007 007090 and US 2011 / 250057. However, such channels do not extend in a radial plane of the crown.

[0010] Also known from documents EP 3 130 753 and US 2014 / 072420 are radial turbomachine injectors in the form of a crown provided with a plurality of air ejection channels. However, these channels do not have an inlet section comprising a triangle and these injectors cannot be manufactured by additive manufacturing.

[0011] Consequently, it would be desirable to have a radial injector to ensure control of the air flow, while allowing it to be distributed in such a way as to cool the turbine as well as possible.

[0012] It is specified that in the present application, the axial direction is defined as a direction substantially parallel to the axis of rotation of the turbomachine, and the radial direction is defined as a direction substantially perpendicular to the axial direction (and therefore to the axis of rotation of the turbomachine). STATEMENT OF THE INVENTION

[0013] According to a first aspect, the invention provides a turbine injector comprising an annular crown extending around a longitudinal axis and having a radially outer edge and a radially inner edge. Furthermore, the crown has a plurality of channels intended to fluidly connect the radially outer edge to the radially inner edge. Each channel extends in a radial plane of the crown and has an inlet opening near the outer edge and an outlet opening near the radially inner edge. Each channel has a progressive variation in its orientation according to a tangential component between the inlet section of the inlet opening and the outlet section of the outlet opening.In a particularly advantageous manner, the variation of the orientation of the channel, according to a tangential component, makes it possible to ensure regular acceleration and the setting in rotation of a gas flow in the channel. Thus, this arrangement advantageously makes it possible to impart a tangential speed to the cooling air, which, in operation, makes it possible to limit the heating of a turbine rotor disk located opposite the injector. In addition, this arrangement makes it possible to guarantee control of the air flow, while allowing it to be distributed so as to cool the turbine as best as possible.

[0014] Each channel can have a predominantly tangentially oriented output section.

[0015] For each channel, the variation of the orientation can be monotonic between the input section and the output section.

[0016] For each channel, the channel outlet section may be geometrically different from the channel inlet section and / or have an area smaller than the area of ​​the channel inlet section.

[0017] Each input section has, according to the invention, the shape of a parallelogram surmounted by a triangle, or the shape of a triangle.

[0018] Each inlet section may have rounded edges.

[0019] Each output section may have a substantially parallelogram shape, preferably a rectangle shape.

[0020] Each channel can have a wall of constant thickness.

[0021] The injector according to the invention is obtained by additive manufacturing. According to another aspect, the invention relates to a turbomachine comprising at least one injector according to the invention. DESCRIPTION OF FIGURES

[0022] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which: There Figure 1 is a view in a radial plane of an injector according to the invention. The Figure 2 is a partial perspective view of the channels of an injector according to the invention. The Figure 3 is a partial view, in a radial plane, of the channels of an injector according to the invention. The Figure 4 is a partial view, in section, in a longitudinal plane of channels of an injector according to the invention. The Figure 5 is a partial view, in a longitudinal plane, of inlet openings of channels of an injector according to the invention. The Figure 6 is a schematic representation of the shape of an inlet section of a channel of an injector according to the invention.

[0023] Throughout the figures, similar elements have identical references. DETAILED DESCRIPTION OF THE INVENTION General architecture

[0024] According to a first aspect, the invention relates to an injector for a high-pressure turbine comprising an annular crown 10 extending around a longitudinal axis A and having an outer edge 12 and an inner edge 14.

[0025] It is specified that in this document the longitudinal axis A is defined as an axis substantially collinear or at least parallel to the axis of rotation of the turbomachine, and the radial axis C is defined as an axis substantially perpendicular to the longitudinal axis A (and therefore to the axis of rotation of the turbomachine).

[0026] The longitudinal axis A is the axis of revolution of the crown 10. Thus, starting from the longitudinal axis A, in a radial direction, we will first encounter the inner edge 14 which is substantially annular, then we will encounter the outer edge 12 which is substantially annular.

[0027] The crown 10 has a plurality of channels 20 intended to connect an air circuit coming from a combustion chamber to the cooling and sealing circuits of a turbine.

[0028] According to a particularly advantageous arrangement, each channel 20 extends in the plane P of the crown 10. It is specified that the plane P of the crown is normal to the longitudinal axis A. Each channel 20 has an inlet opening 22 near the outer edge 12 and an outlet opening 24 near the inner edge 14.

[0029] Furthermore, the crown 10 has a series of longitudinal holes 18 (i.e. parallel to the longitudinal axis A and perpendicular to the plane P). The longitudinal holes 18 make it possible to screw or rivet the crown 10 into a turbomachine. Shape and structure of each channel

[0030] In a particularly advantageous manner, each channel 20 has a progressive variation in its orientation according to a tangential component between the inlet section Φ 22 of the inlet opening 22 and the outlet section Φ 24 of the outlet opening 24. Preferably, the progressive variation in orientation is monotonous. More precisely, by progressive variation in orientation, it is understood a variation in the orientation of a vector normal to the center of a section of the channel 20 and having as its origin the center of said section.

[0031] Preferably, the outlet section Φ 24 is oriented in a non-radial direction. Preferably, the outlet section Φ 24 is oriented in a direction having a tangential component B relative to the longitudinal axis A. It is specified that by tangential component, we mean a component (i.e. a direction) belonging to the plane P of the crown 10 and substantially tangent to the inner edge 14. It is specified that in the present document, the orientation of a section is evaluated with respect to the orientation of a vector which has as its origin the center of said section and which is normal to said section.

[0032] Furthermore, in a particularly advantageous manner, the inlet section Φ 22 is oriented in a direction having a substantially radial component C relative to the longitudinal axis A. It is specified that by substantially radial, it is understood that the component C can be inclined by about twenty degrees relative to a radial axis strictly perpendicular to the longitudinal axis A and belonging to the radial plane P.

[0033] In other words, according to these arrangements the channels are bent with an inlet section Φ 22 oriented according to a radial component C and an outlet section Φ 24 oriented according to a tangential component B. As will be detailed below, this curvature and the orientation of the outlet section Φ 22 are particularly advantageous arrangements of the invention.

[0034] Furthermore, according to another advantageous arrangement, each outlet section Φ 24 of each channel is geometrically different from the corresponding inlet section Φ 22. Each inlet section Φ 22 has an area greater than the area of ​​the corresponding outlet section Φ 24. According to a preferred arrangement, it will be sought to have the ratio "area of ​​the inlet section Φ 22 to area of ​​the outlet section Φ 24" as high as possible.

[0035] However, this ratio is limited by the constraints of integration into a turbomachine. Also, in the context of integration into a turbomachine as manufactured by the applicant, a ratio of between 1 and 10 will be preferred.

[0036] As will be detailed later, the synergy of the variation of the orientation of the channel 20, according to a tangential component, makes it possible to ensure regular acceleration and the setting in rotation of a gas flow in the channel 20. In other words, this arrangement makes it possible to impart a tangential speed to the cooling air, which, in operation, makes it possible to limit the heating of a turbine rotor disk located opposite the injector.

[0037] Typically, each inlet section Φ 22 may have the shape of a parallelogram surmounted by a triangle, as shown in the Figure 6 . According to another arrangement each inlet section Φ 22 can have the shape of a triangle. Generally speaking, the triangle shape can have rounded edges. In other words, the edges of the triangle shape can be fillets.

[0038] Furthermore, the outlet section Φ 24 may have a parallelogram shape. Preferably, the outlet section Φ 24 may have a rectangular shape with curved (convex) walls.

[0039] Thus, according to a preferred embodiment, the section evolves from a rectangular shape topped with a triangle to a rectangular shape with curved (convex) walls.

[0040] According to a particular arrangement, an envelope of each channel 20 varies from a shape of the input section Φ 22 to a shape of the output section Φ 24 .

[0041] Preferably, the envelope of each channel 20 has a wall of constant thickness. However, according to another embodiment, the envelope of each channel 20 may have a wall of variable thickness.

[0042] According to a particular arrangement, each channel 20 can have a length ranging from 10 to 100 millimeters. Functioning

[0043] In operation, a gas flow enters the inlet opening of each channel 20.

[0044] The variation in section and the curvature of each channel 20 makes it possible to accelerate the flow of gas which escapes through the outlet opening 24 of each channel 20. This arrangement makes it possible to maximize the tangential speed of the air at the outlet of the injector. Maximizing the tangential speed of the air at the outlet of the injector is a particularly advantageous arrangement of the invention because it makes it possible to limit the heating of the movable wheel located opposite the injectors. The higher the tangential speed of the air at the outlet of the injector, the more effective the cooling of the movable wheel. Preferably, the tangential speed of the air coming from the injectors is substantially equal to the tangential speed of the movable wheel at the radius where the air from the injectors reaches the movable wheel located opposite.

[0045] In a particularly advantageous manner, the tangential orientation of the outlet opening 24 of each channel 20 makes it possible to have a tangential flow.

[0046] Furthermore, it is noteworthy that preferably, the channels 20 are arranged so that the inlet section Φ 22 of each channel is oriented substantially perpendicular to a main air flow vein in the channel.

[0047] More precisely, to fully appreciate the effect of the injector, one can base oneself on the drive coefficient (Ke) which corresponds to the ratio Vti / Vtm with Vti the tangential speed of the gases at the outlet of the injectors and Vtm the tangential speed of the moving wheel at the radius considered. The injector according to the invention makes it possible to obtain a relatively high Ke compared to known injectors. Typically, the injector according to the invention makes it possible to obtain a Ke of between 1 and 1.5.

[0048] Thus, the invention proposes an injector providing a certain flow rate and which accelerates the speed of the gases passing through them so that the tangential speed of the gases at the outlet of the channels 20 is substantially equal to the tangential speed of a moving wheel located opposite in operation. This makes it possible to effectively cool the moving wheel. Thanks to the injection of a cooling flow with a speed having a significant tangential component.

[0049] In other words, for a given target flow rate, the injector according to the invention makes it possible to provide a significant tangential speed thanks to channels 20, which are more compact, more easily manufactured and lighter than the channels of known injectors. Manufacturing process

[0050] According to another aspect, the invention relates to a method of additive manufacturing of the injector.

[0051] In a known manner, the additive manufacturing process can comprise the superposition of layers of powder melted by an energy source such as a laser or an electron gun. Turbomachine

[0052] According to another aspect, the invention relates to a turbomachine integrating an injector according to the invention. Aircraft

[0053] According to another aspect, the invention relates to an aircraft integrating at least one turbomachine comprising the injector according to the invention.

Claims

1. A turbine injector comprising an annular ring (10) extending around a longitudinal axis (A) and having a radially outer edge (12) and a radially inner edge (14), the ring (10) having a plurality of channels (20) intended to fluidly connect the radially outer edge (12) to the radially inner edge (14), each channel (20) extending in a radial plane (P) of the ring (10) and having an inlet opening (22) near the outer edge (12) and an outlet opening (24) near the radially inner edge (14), each channel (20) having a progressive variation of its orientation according to a tangential component between the inlet section (Φ22) of the inlet opening (22) and the outlet section (Φ24) of the outlet opening (24), characterized in that it is obtained by additive manufacturing and in that each inlet section (Φ22) has the shape of a parallelogram surmounted by a triangle, or the shape of a triangle.

2. The injector according to claim 1, wherein each channel (20) has a tangentially oriented outlet section (Φ24).

3. The injector according to any one of claims 1 or 2, wherein, for each channel (20), the variation in orientation is monotonic between the inlet section (Φ22) and the outlet section (Φ24).

4. The injector according to any one of claims 1 to 3, wherein, for each channel (20), the outlet section (Φ24) of the channel (20) is geometrically different from the inlet section (Φ22) of the channel (20) and / or has a smaller area than the area of the inlet section (Φ22) of the channel (20).

5. The injector according to any of the preceding claims, wherein each inlet section (Φ22) has rounded edges.

6. The injector according to claim 4, wherein each outlet section (Φ24) has a parallelogram shape.

7. The injector according to claim 6, wherein each outlet section (Φ24) has a rectangular shape.

8. The injector according to any one of claims 1 to 7, in which each channel (20) has a wall of constant thickness.

9. A turbomachine comprising at least one injector according to any one of claims 1 to 8.