Bucket including a shroud having a defrost air passage duct

Abstract

The invention relates to a blade comprising a shroud (14) attached to the upstream end of the body of the blade, the shroud (14) comprising an upstream end forming the leading edge of the blade, the shroud (14) further comprising a nose (141) and pressure and suction fins, the leading edge being upstream of the nose, the pressure and suction fins being attached laterally to the blade, the fins extending from the nose, the blade comprising a defrost air passage duct (15) arranged in the nose and extending radially therein, the duct (15) having an inner end (151) and a radially outer end, the inner end emerging opposite the root (125) and the radially outer end emerging from the nose between the leading edge and its junction at the pressure fins.

Description

Technical Field

[0001] The present invention relates to a turbine blade having de-icing capabilities and an impeller of a fan rotor including such a blade. Background Art

[0002] A turbine fan rotor generally comprises a disk carrying blades on its periphery, the roots of the blades engaging in grooves in the periphery of the disk.

[0003] The dimensions of the blades must allow for optimal aerodynamic performance while ensuring mechanical strength and limiting the acoustic signature of the blades. Improvements in the aerodynamic performance of the blades tend to increase the outer diameter and thus the span of the blades, which tends to reduce the rotational speed.

[0004] One problem is that by reducing the rotational speed, ice may form on the blades; higher speeds allow the ice to separate from the blades.

[0005] Icing can harm the aerodynamic performance of the fan, which is detrimental. Summary of the Invention

[0006] The present invention aims to overcome at least one of these drawbacks.

[0007] To this end, according to a first aspect, the invention proposes a blade comprising a body comprising an upstream end and a downstream end in the flow direction of the air flow, a radially outer tip, and a radially inner root, the blade comprising, between the tip and the root, a blade and a support portion, the blade being intended to operate aerodynamically in the air flow, the support portion being connected to the root portion itself, the root portion being intended to be fixed in a slot cavity of a rotor disk of an impeller of a turbine fan, the blade further comprising a shroud attached to the upstream end of the body, the shroud comprising an upstream end forming the leading edge of the blade, the shroud further comprising a nose and pressure and suction fins, the leading edge being located upstream of the nose, the pressure and suction fins being attached laterally to the blade, the fins extending from the nose, the blade comprising a de-icing air duct arranged in the nose and extending radially therein, the duct having an inner end and a radially outer end, the inner end opening opposite the support portion, the radially outer end opening from the nose between the leading edge and its junction with the pressure fin.

[0008] According to a first aspect, the invention is advantageously completed by the following features, taken individually or in one of the technically possible combinations of such features:

[0009] - the radially outer end portion is configured so that the air circulating in the duct is discharged in the flow direction of the air flow in the turbine fan;

[0010] the air passage duct is arranged in a first half of the height of the blade taken between the tip and the root of the blade, preferably in a first half of the height taken between the support and the tip of the blade;

[0011] -The catheter is cylindrical, straight, or serpentine;

[0012] -The catheter is obtained by additive manufacturing method;

[0013] - The width or inner diameter of the catheter is less than or equal to 3 mm;

[0014] The vanes comprise means for conveying de-icing air intended to flow from the high-pressure compressor towards the inlet of the de-icing air channel duct.

[0015] The means for conveying deicing air consist of ducts formed in the support portion of the blade or of ducts extending at the connection disk of the blade, and also comprise a connection portion connecting the ducts to the deicing air channel ducts.

[0016] According to a second aspect, the invention comprises a turbine fan impeller comprising at least one blade according to the first aspect of the invention.

[0017] According to a third aspect, the invention comprises a turbine fan impeller comprising at least one blade according to the first aspect of the invention and a disk, the root of the blade being inserted into the disk, the disk comprising an edge, the wheel being such that the means for conveying de-icing air are constituted by ducts formed by machining the edge of the disk.

[0018] According to a fourth aspect, the present invention relates to a turbomachine comprising an impeller according to the second aspect or according to the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features, objects and advantages of the present invention will appear from the following description, which is entirely illustrative and non-limiting and should be read in conjunction with the accompanying drawings, in which:

[0020] Figure 1 shows a schematic cross-sectional view of an upstream portion of a turbine;

[0021] Figure 2 shows a blade according to the invention;

[0022] Figure 3 Shown Figure 2 Detailed view of the blades;

[0023] Figure 4 and Figure 5each showing a view of a blade with a device for delivering de-icing air according to a first variant of embodiment;

[0024] Figure 6 shows a view of a blade with a device for delivering de-icing air according to a second variant of embodiment;

[0025] Figure 7 A view showing a locking portion for fixing a blade in a second variant of the embodiment is shown.

[0026] Similar elements are denoted by the same reference numerals throughout the drawings. DETAILED DESCRIPTION

[0027] Figure 1 A cross-sectional view of the upstream portion of the turbine is shown. In particular, the fan and the inlets of the primary and secondary flow channels I and II are visible.

[0028] The fan 1 comprises in particular an impeller 10 comprising blades 11 each fixed to a slot 2 of a rotor disk 3. The fan 1 also comprises here a casing 4 surrounding the impeller, but the blades to be described may also belong to an unducted fan.

[0029] Figure 2 A detailed view of a blade 11 is shown. Such a blade 11 comprises a body 12. Preferably, the body is made of a composite material having a 3D woven preform embedded in a resin.

[0030] The body 12 comprises an upstream end 121 and a downstream end 122 , a radially outer tip 123 and a radially inner root 124 , in the flow direction of the air flow F. It is also provided that in the following, upstream and downstream are defined relative to the flow direction of the flow, the concept of radial direction being understood relative to the axis of rotation of the turbine.

[0031] The blade comprises, between a tip 123 and a root 124 , a blade 13 intended to operate aerodynamically in the air flow. The blade 13 constitutes the aerodynamic part of the blade 11 .

[0032] Furthermore, the blade 11 comprises a support portion 125 connected to a root portion 124, which is itself fixed in the slot 2 of the rotor disk 3. Thus, the support portion 125 is the portion of the blade 11 between the root portion 124 and the inter-blade platform 5. The root portion 124, for its part, is the lower portion of the blade that is inserted into the slot 2 of the disk. Consequently, the blade 13 is located above the support portion 125 (in the direction between the root and the tip of the blade) and above the inter-blade platform 5.

[0033] In order to protect the bucket 11, a shroud 14 is attached to the upstream end of the body 12 of the bucket 11. In particular, the shroud 14 is attached to the blades 13 of the bucket 11.

[0034] Such a shroud 14 makes it possible to protect the blades from bird strikes and to contribute to the problems associated with erosion. The shroud 14 comprises an upstream end forming the leading edge 144 of the blade 11. Figure 2 In FIG, the outline of the body of the bucket 11 can be seen below the shroud 14 in dotted lines.

[0035] Advantageously, the shroud 14 is metal, preferably, the shroud is made of titanium. Other types of metals may also be provided. It will be appreciated that the type of material selected for the shroud must satisfy the mechanical and aerodynamic stresses.

[0036] The shroud 14 is fixed to the blade 11 by gluing or welding on the body 12 of the blade 11 .

[0037] In addition, the shroud 14 comprises a solid nose 141 and two fins 142, 143 (a pressure side fin 142 and a suction side fin 143). The fins extend from the nose 141 and are preferably attached to the body of the blade 11 by gluing. In addition, the thickness of the fins 142, 143 is less than that of the solid nose.

[0038] To avoid ice formation at the leading edge 144, and as Figure 3 As shown, a de-icing air passage duct 15 is provided within the shroud 14. The duct 15 is formed in a solid nose portion 141 of the shroud 14. Since the solid nose portion is the thickest part of the shroud 14, the performance of the blade is least impaired at this location. In fact, providing the duct means making structural modifications to the shroud 14, which is subject to high mechanical stress.

[0039] The duct 15 has an air inlet 151 and an air outlet 152. The duct extends radially along a radial direction extending between the root 125 and the tip 123 of the blade 11. The air inlet 151 is located opposite the support portion 125 at the connection 126 where the support portion connects to the blade 13, while the air outlet 152 opens from the solid nose portion between the leading edge and the pressure surface fin. The duct allows air to flow downstream without obstructing the flow of air through the fan. Preferably, the air outlet 152 is located at the lowest pressure point in the fan.

[0040] In order for the outlet of the duct 15 to open from the solid nose between the leading edge and the pressure surface fin, the duct has a first straight portion 15R extending radially in a direction taken between the root 125 and the tip 123 of the blade 11, and a second curved portion 15C extending from the end of the first straight portion 15R farthest from the root 124.

[0041] Preferably, the duct 15 is obtained by an additive manufacturing method and the duct can adopt a variety of shapes. In the figures, the duct 15 is curved and has a cylindrical inner cross section, but the duct can adopt other shapes. In particular, the duct can be thin and straight or sinuous. The criterion adopted for the shape of the duct 15 is the mechanical strength of the shroud 14. According to the term "sinuous", it is considered that the duct is substantially straight over a large part of the radial extent of the duct and is curved at the radially outer end 154 of the duct, which opens from the nose between the leading edge and the junction with the pressure surface fin, as Figure 2 shown.

[0042] In order to modify the shield 15 as little as possible and not to change the mechanical properties of the shield too much, the diameter or width of the conduit 15 inside the shield is less than or equal to 3 mm.

[0043] By circulating air in the duct 15 inside the shroud 15 , ice formation is avoided.

[0044] The duct 15 extends over the radial height of the blade 13. This radial height of the duct 15 was chosen based on where icing most often occurs, without altering the aerodynamic and mechanical performance of the blade. In practice, the primary mechanical criterion is to control the ingestion of foreign objects. Large bird ingestion is critical at an altitude of approximately 50% of the blade height, while medium-sized bird ingestion is critical at an altitude of approximately 85% of the blade height. Consequently, the base of the blade (below 50% of the blade height) is less critical for ingestion, and slight mechanical degradation is acceptable at this location. This is why the duct is located in this section.

[0045] In order to avoid icing, hot air is preferably circulated in the duct 15 , which hot air can be taken from different locations in the turbine.

[0046] Preferably, the air taken is from a high-pressure compressor located downstream.Any other source for taking the air in the flow can be envisaged, such as, for example, a turbine in the case of an open rotor fan.

[0047] Air can be delivered from the high pressure compressor in a variety of ways.

[0048] like Figure 4 and Figure 5As shown, according to a first embodiment, a duct 16 is provided, which conveys air taken from the high-pressure compressor to the inlet of duct 15. Preferably, this duct 16 is disposed in support portion 125. To this end, a cavity 127 is provided in support portion 125, and duct 16 is inserted into cavity 127. This cavity 127 is obtained by weaving a core stripping portion along the entire length of the blade chord. Thus, a curved connection portion 153, which constitutes the second portion of duct 16, enables connection of duct 16 to the de-icing air channel duct 15.

[0049] Alternatively, as Figure 6 As shown, according to a second variant, the air comes from the disk 3 rather than from the blade's support 125. According to this alternative, no duct is required in the composite material. Instead, a duct 17 is machined into the disk's edge 31 to allow air to flow from the disk downstream to the shroud 18. Thus, a duct 18 extends perpendicularly from the duct 17 to meet with the duct's inlet 151 in the leading edge 15. Along its path, the duct 17 passes through the disk's locking portion 20 and wedge 19. To install the blade in the slot 2, an axial wedge 19 slides under the root 124 to ensure radial retention of the blade in the slot 2. Furthermore, a locking portion 20, perpendicular to the wedge 19, is positioned in a recess provided in the side of the slot 2 on the upstream side of the disk 3 (for a further detailed description of installation using the locking portion 20, reference can be made to document WO 2012 / 150425).

[0050] like Figure 6 As shown, the wedge 19 comprises a portion 19a housed in the slot 2 and an upstream end protrusion 19b which extends beyond the disk and serves as a connection to the locking portion 20. The connection is ensured by a screw 21 which passes through the protrusion 20a and the protrusion 19b fixed to the locking portion 20, the assembly securing the blade in its slot.

[0051] This installation is very simple since the wedge 19 comprises a number of holes (not shown). On the other hand, in order to pass through the locking portion 20, the duct 18 (for example a flexible tube) passes through a honeycomb structure 20c (called Nida) located just below the solid nose of the shield 15. Figure 7 A perspective view of the locking part 20 is shown, which has a channel 20b for the pipe 18 and a Nida 20c.

[0052] Finally, to ensure sealing, two bellows-type seals 6 are provided at each interface: one between the conduit 17 and the pipe 18 , and one between the inlet 151 of the conduit 15 and the pipe 18 .

Claims

1. A blade (11), comprising a body (12), said body comprising an upstream end and a downstream end in the flow direction of the air flow, a radially outer tip (123), a radially inner root (124), said blade (11) comprising a blade (13) and a support portion (125) between said radially outer tip (123) and said radially inner root (124), said blade being intended to work aerodynamically in said air flow (F), said support portion being connected to said radially inner root, said radially inner root being intended to be fixed in a slot cavity of a rotor disk of an impeller of a turbine fan, The blade (11) includes a shroud (14) attached to the upstream end of the body, the shroud (14) including an upstream end forming a leading edge (144) of the blade, the shroud (14) also including a nose (141) and pressure surface fins (142) and suction surface fins (143), the leading edge being located upstream of the nose, the pressure surface fins and suction surface fins being attached laterally to the blade (13), the pressure surface fins (142) and the suction surface fins (143) extending from the nose (141), the blade (11) including a deicing air passage duct (15) provided at the nose (141) and extending radially within the nose (141), the deicing air passage duct (15) has an inner end (151) and a radially outer end (152), the inner end forming an air inlet of the deicing air passage duct (15), the air inlet opening opposite to the support portion (125), the radially outer end forming an air outlet, the air outlet opening from the nose (141) between the leading edge and the junction between it and the pressure surface fin (142), the deicing air passage duct (15) having a first straight portion (15R) and a second curved portion (15C), the second curved portion extending from the end of the first straight portion (15R).

2. The blade according to claim 1, wherein: The radially outer end portion is configured such that air circulating in the de-icing air passage duct (15) is discharged along the flow direction of the air flow in the turbine fan.

3. The blade according to claim 1 or 2, wherein: The de-icing air passage duct (15) is arranged in a first half of the height of the blade taken between the radially outer tip and the radially inner root of the blade.

4. The blade according to claim 1 or 2, wherein: The de-icing air passage conduit (15) is cylindrical, straight or serpentine.

5. The blade according to claim 1 or 2, wherein: The de-icing air channel duct (15) has been obtained by an additive manufacturing method.

6. The blade according to claim 1 or 2, wherein: The width or inner diameter of the deicing air channel conduit (15) is less than or equal to 3 mm.

7. The blade according to claim 1 or 2, comprising conveying means for conveying de-icing air intended to flow from a high-pressure compressor towards the inlet of the de-icing air channel duct.

8. The blade according to claim 7, wherein: The conveying device for conveying deicing air is composed of a duct (16) formed in the support part of the blade or a duct (17) extending at the connection disk of the blade, and the conveying device also includes a connection part connecting the duct (16, 17) and the deicing air channel duct (15).

9. The blade according to claim 1 or 2, wherein: The de-icing air passage duct (15) is arranged in a first half of the height taken between the support portion and the radially outer tip of the blade.

10. A turbine fan impeller comprising at least one blade (11) according to any one of claims 1 to 9.

11. A turbine fan impeller comprising at least one blade (11) according to any one of claims 1 to 9 and a disk (3), the radially inner root of the blade being inserted into the disk, the disk (3) comprising an edge (31), the turbine fan impeller being such that the delivery means for delivering de-icing air are constituted by ducts formed by machining the edge (31) of the disk (3).

12. A turbine comprising a turbine fan wheel according to claim 10 or 11.

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