Ingestion-resistant moving impeller for turbomachine compressor

Abstract

Ingestion-Resistant Rotating Impeller for Turbomachine Compressor. One aspect of the invention relates to a rotating impeller (1) comprising an assembly of impellers (3) mounted radially on an internal annular support (2) that rotates about an axis X. Each impeller has a leading edge (6) forming its upstream edge. At least one of the impellers in the assembly is a reinforced splitting impeller (8), the leading edge of which extends upstream along the X axis relative to the other impellers (9). This rotating impeller is preferably intended to serve as a rotor in the upstream stage of a turbomachine compressor. Figure to be published with the abbreviation: Figure 1

Description

Title of the invention: Ingestion-resistant moving blade wheel for turbomachine compressor TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of aircraft turbomachines.

[0002] The present invention relates to a moving bladed wheel intended to serve as a rotor stage in a turbomachine compressor. It also relates to a turbomachine compressor and an associated turbomachine comprising such a moving bladed wheel. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] When flying, an aircraft is likely to encounter foreign solid bodies, such as pieces of ice or hailstones at altitude, or even small birds during takeoff or landing phases. These solid bodies may accidentally be "ingested", i.e. sucked in, by the aircraft's turbomachines which draw in a large quantity of air for their operation. They then strike the moving blades of the compressor located upstream of the turbomachine and cause mechanical damage to them which may lead to breakdowns or accidents.

[0004] For this reason, the moving blades of turbomachine compressors are conventionally sized so as to be able to withstand such impacts without breaking or deforming in an unacceptable manner. The moving blades of the upstream stage of the compressor are thus designed to be particularly robust.

[0005] However, this is done to the detriment of the aerodynamic performance of these blades. Indeed, in order for the blades to be able to adequately resist ingestion, designers are often forced to discard blade profiles that are too fragile, but which would be more efficient from an aerodynamic point of view.

[0006] The invention aims to overcome this drawback by proposing a new design of a wheel with moving blades making it resistant to ingestion regardless of the profile chosen for the moving blades. Thanks to the invention, the designer is freed from the constraint of resistance to ingestion for most of the blades of the wheel and can therefore focus solely on their aerodynamic efficiency. New, more efficient shapes become possible for these blades, whereas they were previously excluded because they were too fragile in the event of an impact. A significant improvement in the overall aerodynamic performance of the relevant stage of the compressor can thus be targeted. Summary of the invention

[0007] A first aspect of the invention relates to a moving bladed wheel comprising a set of blades mounted radially on an inner annular support movable in rotation around an axis X, each of these blades having a leading edge which constitutes its most upstream edge.

[0008] According to the invention, at least one of the blades of the set of blades is a reinforced fractionating blade, the leading edge of which protrudes along the X axis in the upstream direction relative to the leading edge of the other blades of the set of blades.

[0009] In the event of "ingestion" of a solid body in the turbomachine, the tangential speed of the compressor blades is always much higher than the axial speed of the sucked solid body.

[0010] As it protrudes upstream relative to the other blades, the solid body always encounters the splitting blade before the other blades of the moving impeller and it is therefore against the splitting blade that the impact with the solid body occurs.

[0011] As it is reinforced, the fractionating blade satisfactorily withstands this shock, without breaking or deforming in an unacceptable manner.

[0012] As it progresses axially, the sucked solid body is abraded by the rotation of the fractionating blade which breaks it into very small debris before it encounters the other blades of the moving bladed wheel which are further downstream.

[0013] Thus split, the solid body no longer presents any danger to the rest of the blades of the wheel, which can therefore have any profile, even fragile. The designer can therefore freely choose the profile of these blades based solely on aerodynamic considerations, without taking into account their resistance to ingestion.

[0014] The invention thus makes it possible to predetermine in advance which blade will be affected in the event of ingestion of a solid body and to reinforce it accordingly. The other blades of the wheel, which are guaranteed to be preserved, may be more fragile. They can therefore be designed freely, with any profile giving them better aerodynamic performance, without being limited by their impact resistance capacity.

[0015] Advantageously, several blades of the set of blades may be fractionating blades, their number remaining less than or equal to 10% of the total number of blades of the set of blades.

[0016] This configuration provides better protection for the other blades of the wheel, because it guarantees that any solid body will be completely abraded regardless of its size and regardless of the speed of the aircraft engine governing the rotational speed of the moving bladed wheel.

[0017] However, the number of fractionating blades remains limited compared to the number total number of blades in the wheel. The overall aerodynamic performance of the wheel can therefore be preserved.

[0018] In this case, the fractionating blades are for example grouped into one or more groups of consecutive blades.

[0019] The fractionation of the solid body is then very effective because it is struck several times successively by the consecutive fractionation blades, before being able to progress axially in the downstream direction.

[0020] Advantageously, the fractionating blades or groups of consecutive fractionating blades can be distributed according to a regular radial arrangement, that is to say that the fractionating blades or groups of blades are arranged radially with a constant angular spacing. This arrangement makes it possible to improve the balancing of the moving bladed wheel.

[0021] Several embodiments are possible so that the leading edge of the fractionating blade protrudes along the X axis in the upstream direction relative to that of the other blades.

[0022] For example, the fractionating blade may be larger along the X axis than the other blades. The attachment of the fractionating blade to the inner annular support may advantageously remain the same as that of the other blades of the wheel. The assembly of the blades is thus simplified.

[0023] For example, the fractionating blade can be offset along the X axis in the upstream direction relative to the other blades. The fractionating blade can then remain identical to the other blades of the wheel, only its attachment to the inner annular support needs to be modified. The manufacture of the blades is therefore simpler and more economical.

[0024] For example, the fractionating blade can be pivoted about a radial axis passing through the fractionating blade in a direction that tilts its leading edge upstream. The fractionating blade can then remain identical to the other blades of the wheel, only its inclination needs to be modified. The manufacture of the blades is therefore simpler and more economical.

[0025] For example, the fractionating blade may include an added extension piece that moves its leading edge upstream. The fractionating blade may then be identical to the other blades of the wheel and be fixed in the same way, with the same inclination, the desired overhang being provided by an additional piece. This simplifies both the manufacture and the assembly of the blades.

[0026] In this case, the extension piece can advantageously be a reinforcement piece. The two functions are then advantageously fulfilled by a single piece.

[0027] Several embodiments are possible for the fractionating blade to be reinforced.

[0028] For example, the fractionating blade may be reinforced due to a different shape, thickness or material than the other blades.

[0029] For example, the fractionating blade can be reinforced by means of a reinforcing piece attached to the fractionating blade.

[0030] A second aspect of the invention relates to a compressor comprising at least one moving blade wheel as described above.

[0031] A third aspect of the invention relates to a turbomachine comprising such a compressor.

[0032] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0033] The figures are presented for information purposes only and in no way limit the invention.

[0034] [Fig-1] is a schematic perspective view of a portion of a moving bladed wheel according to a first example of the invention.

[0035] [Fig.2], [Fig.3], [Fig.4], [Fig.5] and [Fig.6] are tangential sectional views schematically illustrating several embodiments of the first two stages of a compressor according to the invention.

[0036] [Fig.7], [Fig.8], [Fig.9] and [Fig. 10] are perspective views illustrating diagram technically several embodiments of a moving bladed wheel according to the invention. DETAILED DESCRIPTION

[0037] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0038] In the present application, the terms "upstream" and "downstream" are defined with respect to the normal flow direction of gas (from upstream to downstream) through a compressor.

[0039] The axis of rotation of the compressor's moving bladed wheel is also called the "wheel axis" or "compressor axis". This axis is referred to as X in the figures. The axial direction corresponds to the direction of this axis of rotation and a radial direction is a direction perpendicular to the wheel axis and intersecting this axis.

[0040] Unless otherwise specified, the adjectives "inner", "internal", "outer", "external" are used in the present application with reference to a radial direction so that the inner part of an element is, in a radial direction, closer to the axis of the wheel than the outer part of the same element.

[0041] The figures show several examples of a moving bladed wheel 1 according to the invention.

[0042] This wheel 1 conventionally comprises an annular support 2 on which are arranged a plurality of blades 3 (also called vanes) which extend radially from the external face 4 of the annular support 2. This wheel 1 is movable in rotation around of an axis X passing through the center O of the annular support 2.

[0043] The blades 3 are movable in rotation around the axis X due to the rotation of the wheel 1. They are preferably mounted fixed, that is to say non-orientable, on the annular support 2.

[0044] As visible in Figures 2 to 6, the blades 3 preferably have a drop-shaped section for aerodynamic reasons. They thus comprise a core 5, thick and rounded on the upstream side which tapers to a point towards the downstream side, and terminate on their most upstream side with a leading edge 6 and on their most downstream side with a trailing edge 7.

[0045] Furthermore, as can be seen in [Fig.l], these blades 3 are conventionally twisted in order to give an appropriate angle of incidence over their entire length to the air flow which circulates through the wheel 1.

[0046] According to the invention, at least one of these blades 3 is a fractionating blade 8, which protrudes along the X axis in the upstream direction relative to the other blades of the wheel 1 which will be called standard blades 9 in the remainder of this application.

[0047] It is obvious that this designation of standard blades 9 is chosen solely for the purpose of editorial simplification and in no way prejudges the originality of the characteristics or the shape of these blades.

[0048] The protrusion of the fractionating blade 8 compared to the standard blades 9 is for example of the order of approximately 1 to 2 millimeters. But it may be greater for an application where the rotation speed of the wheel 1 is low.

[0049] Several embodiments are possible to obtain this protrusion of the fractionating blades 8 compared to the standard blades 9. Some examples are shown in Figures 2 to 5.

[0050] In these figures, the alignment of the leading edges 6 of the standard blades 9 is symbolized by a line 10 and the alignment of their trailing edges 7 by a line 11.

[0051] In the example of [Fig.2], the fractionating blade 8 is offset upstream relative to the standard blades 9, i.e. translated along the X axis in the upstream direction.

[0052] It can be seen that its leading edge 6 crosses the line 10 and protrudes upstream relative to the leading edges 6 of the standard blades 9. In addition, its trailing edge 7 is no longer in contact with the line 11 because it is also offset upstream relative to the trailing edges 7 of the standard blades 9.

[0053] In the example of [Fig. 3], the fractionating blade 8 is longer along the X axis than the standard blades 9 and protrudes upstream relative to them. Its leading edge 6 crosses the line 10, while its trailing edge 7 remains aligned with those of the standard blades 9 along the line 11.

[0054] In the example of [Fig.4], the inclination of the fractionating blade 8 has been modified. This is pivoted radially so as to tilt its leading edge 6 upstream. Due to this pivoting, its leading edge 6 crosses line 10 and its trailing edge 7 crosses line 11.

[0055] In this case, if the blades 3 are orientable blades, the fractionating blade 8 will be pivoted more than the standard blades 9 so as to make its leading edge 6 protrude beyond that of the standard blades 9.

[0056] In the example of [Fig. 5], the fractionating blade 8 comprises an extension piece 12 which is attached on the upstream side, on the rounded part of its core 5. The leading edge 6 of the fractionating blade 8 is thereby displaced onto the extension piece 12 and is thus offset upstream beyond the line 10. On the other hand, the trailing edge 7 of the fractionating blade 8 remains aligned with those of the standard blades 9 on the line 11.

[0057] In the example of [Fig. 1], there are also extension pieces 12 attached to the upstream part of the fractionating blades 8. Advantageously, these extension pieces 12 extend radially over the entire height of the fractionating blades 8 and thus constitute the part projecting upstream of the fractionating blades. In addition to extending them upstream, these extension pieces 12 can advantageously serve simultaneously to reinforce the fractionating blades 8.

[0058] Indeed, due to their upstream projection, the fractionating blades 8 will be those which will be struck by a solid body 13 in the event of ingestion. They are therefore reinforced so as to be sufficiently strong to be able to withstand such an impact without breaking or deforming in an unacceptable manner. On the contrary, they are thus capable of abrading the solid body 13 by fractionating it during the rotation of the fractionating blade 8.

[0059] Several embodiments are possible to obtain this reinforcement.

[0060] By way of non-limiting example, mention may be made of fractionating blades 8 made thicker or with a different and more resistant material than that of the standard blades 9, or even fractionating blades 8 having a specific shape which increases their resistance, in particular with reinforcing ribs or beads. Alternatively or in addition, additional reinforcing pieces may be added to them.

[0061] Some examples are shown in the figures below.

[0062] In [Fig.6], the core 5 of the fractionating blades 8 is thicker than that of the standard blades 9, which provides better resistance.

[0063] In Figures 1 and 5, the fractionating blades 8 are reinforced by the extension pieces 12 which simultaneously serve as reinforcing pieces 14. These may be, for example, metal reinforcing pieces 14, preferably attached by gluing, on a 5 core in composite material.

[0064] Depending on the requirements, the wheel 1 according to the invention may comprise one or more fractionating blades 8.

[0065] Indeed, depending on the size and spacing of the blades of the wheel 1, as well as the expected rotation speed of the latter in the normal operating range of the turbomachine in which it will be installed, it may be necessary to provide several fractionating blades 8 to guarantee optimal operation.

[0066] Similarly, the number of fractionating blades 8 can be increased if it is desired to guarantee increased safety even in the most unfavorable conditions, that is to say in the event of ingestion of a large solid body in a flight phase of the aircraft where the rotation speed of the wheel 1 is low, on landing for example.

[0067] Nevertheless, the number of fractioning blades 8 will remain low compared to the total number of blades 3, preferably less than or equal to 10%, so as not to harm the overall aerodynamic properties of the wheel 1. This generally involves one to six fractioning blades 8 out of a total of approximately one hundred blades 3.

[0068] Those skilled in the art will easily be able to find the most suitable compromise for each specific application, also taking into account the weight saving resulting from the addition of additional fractionating blades 8.

[0069] When the wheel 1 comprises several fractionating blades 8, several arrangements can be envisaged for their positioning. Some non-limiting examples of possible distributions have been illustrated in the figures.

[0070] In the examples of [Fig.l] and 7, the wheel 1 comprises a group 15 of respectively two and three consecutive fractionating blades 8.

[0071] In the example of [Fig.8], the wheel 1 comprises two groups 15 of two consecutive fractionating blades 8, the two groups 15 being diametrically opposed.

[0072] In the examples of figures 9 and 10, the wheel 1 comprises respectively three and four non-consecutive fractionating blades 8, which are distributed according to a regular radial arrangement, that is to say they are arranged radially with an angular spacing of respectively 120° and 90°.

[0073] A regular radial arrangement of the blades 8 or groups 15 of fractionating blades 8, as in FIGS. 8 to 10 for example, is advantageous, because it makes it possible to very simply balance the wheel 1 in terms of weight to obtain correct behavior during rotation in operation.

[0074] When the wheel 1 has only one fractionating blade 8 or a non-regular radial arrangement of these blades 8 or groups 15 of fractionating blades 8 as in FIGS. 1 and 7 for example, this balancing must be done differently, for example by means of weights judiciously arranged on the annular support 2 and which serve as counterweights.

[0075] The wheel 1 is preferably intended to serve as a rotor 16 in a compressor 17 of a turbomachine 18.

[0076] Conventionally, such a compressor 17 comprises one or more stages 19, each stage comprising a rotor 16 which comprises a series of rotating blades 3, followed by a stator 20 formed of a series of fixed blades 21.

[0077] For the reasons set out above, a moving blade wheel 1 according to the invention can advantageously be used as rotor 16 in the first stage 19 of the compressor, that is to say the one located furthest upstream of the compressor, which will be the most exposed in the event of ingestion of solid body 13.

[0078] By way of example, Figures 2 to 6 schematically show a compressor 17 with two stages 19, in which the rotor 16 of the first stage 19 (the one furthest upstream) is a wheel 1 according to the invention.

[0079] For greater safety and as shown schematically in [Fig. 6], the rotor 16 of the second stage 19 (the one immediately following the most upstream stage) may also be a wheel 1 according to the invention. Its fractionating blade(s) 8 may then continue to fractionate the debris from the solid body 13 which arrives at this second stage after having passed through the first stage 19.

[0080] The rotors of the following stages of the compressor can obviously be made in the same way.

Claims

Claims

1. A movable bladed wheel (1) comprising a set of blades (3) mounted radially on an inner annular support (2) rotatable about an axis X, each of said blades (3) having a leading edge (6) which constitutes its most upstream edge, characterized in that at least one of the blades (3) of the set of blades is a reinforced fractionating blade (8), the leading edge (6) of which projects along the axis X in the upstream direction relative to the leading edge (6) of the other blades (9) of the set of blades.

2. A movable impeller (1) according to claim 1, characterized in that several blades (3) of the set of blades are fractionating blades (8), their number remaining less than or equal to 10% of the total number of blades (3) of the set of blades.

3. Movable impeller (1) according to claim 2, characterized in that the fractionating vanes (8) are grouped into one or more groups (15) of consecutive vanes.

4. A movable impeller (1) according to claim 2 or 3, characterized in that the fractionating vanes (8) or groups (15) of consecutive fractionating vanes (8) are distributed in a regular radial arrangement.

5. A movable impeller (1) according to one of the preceding claims, characterized in that the fractionating blade (8) is larger along the X axis than the other blades (9), or is offset along the X axis in the upstream direction relative to the other blades (9), or is pivoted about a radial axis passing through the fractionating blade (8) in a direction which causes its leading edge (6) to tilt upstream.

6. Movable bladed wheel (1) according to one of the preceding claims, characterized in that the fractionating blade (8) comprises an attached extension piece (12) which moves its leading edge (6) upstream.

7. Movable impeller (1) according to claim 6, characterized in that the extension piece (12) is a reinforcing piece (14).

8. Movable bladed wheel (1) according to one of the preceding claims, characterized in that the fractionating blade (8) is reinforced due to a shape, thickness or material different from that of the other blades (9) of the blade assembly, or by means of a reinforcing piece (14) attached to the fractionating blade (8).

9. Compressor (17) comprising at least one moving bladed wheel (1) according to one of claims 1 to 8.

10. A turbomachine (18) comprising a compressor (17) according to claim 9.

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