FR3046235A1 - INTERCHANGEABLE SUPPORT FOR FASTENING A TURBOMACHINE - Google Patents

Abstract

The invention relates to an interchangeable support (1) for fixing a turbomachine, characterized in that it comprises a main body (2) which comprises at least two plane faces, a first face adapted for attachment to an external structure and a second face adapted for attachment to the turbomachine, said main body (2) being hollow and having a cavity (3) which comprises two ends and which extends perpendicularly to a main direction of elongation of said main body (2) and which opens on either side thereof, said cavity (3) being filled with a liquid and being closed at its two ends by a flexible partition (31), said support (1) further comprising a keel cushion (4) projecting into the cavity (3) extending rigidly from one of the walls of the main body (2), said damping keel (4) and the liquid involved in the damping deformations cr ed on the main body (2) by the turbomachine when the latter is mounted on the structure.

Description

The present invention relates to an interchangeable support for fixing a turbomachine to a structure for regulating the dynamic loads created by the turbomachine.

More specifically, it relates to an interchangeable support for fixing a turbomachine to a test stand or to an aircraft which makes it possible to give the fastening of the turbomachine a desired flexibility and by impacting the vibratory signature of the turbomachine of a controlled way.

GENERAL TECHNICAL FIELD AND STATE OF THE ART

The dynamic situation of a structure (the structure vibration modes and the structural damping) to which a turbomachine is attached has a direct impact on the internal charges of the turbomachine, on the loads applied to the fasteners of the turbomachine to the structure, as well as the dynamic situation of the turbomachine itself.

Thus, three scenarios can arise: - A too rigid structure leads to excessive loads in the fasteners of the turbomachine to the structure, insofar as the structural damping of the structure does not reduce the impact of major phenomena (such as the loss of a dawn), and can thus lead to a stall of the turbomachine. - A too flexible structure may imply that the structure does not hold the ultimate loads that can be transmitted to it by the turbomachine during major phenomena. In addition, in the case where the structure is a test bench, too much flexibility of the test bench distorts the simulations that are performed, because the loads transmitted to the test stand by the turbomachine are lower than the loads that will be transmitted when the turbomachine will be attached to an aircraft. This point is a major issue for a certification test (such as the intentional loss of a blade) during which too low loads and therefore not representative of an event in service will be measured in case of too much flexibility. A structure with an acceptable flexibility, but which modifies the vibratory signature of the turbomachine in an undesired manner. Such a situation poses a problem for balancing the turbomachine, and more particularly for balancing a turbomachine on a test bench. Indeed, in the case where the test bench modifies the vibratory signature of the turbomachine differently with respect to the aircraft to which the turbomachine will be fixed, the balancing which is performed on the test stand is not suitable. for the use of the turbomachine that will be made after mounting on the aircraft.

Currently, it is necessary to adapt all or part of the structure specifically for each turbomachine model or for each variant of the same turbomachine model, to give the structure the desired flexibility and ensure that it does not does not modify the vibration signature of the turbomachine in an undesired manner, which is particularly expensive and may require a lot of time. Thus, in the case where the structure is a test bench, it is currently necessary to design entire strata of the test bench (and particularly the fastening devices of the test bench to the turbomachine) in a specific manner. for the turbomachine, so that the test bench has the desired flexibility and changes the vibratory signature of the turbomachine in a manner identical to the aircraft to which the turbomachine must be fixed.

GENERAL PRESENTATION OF THE INVENTION

A general object of the invention is to propose a solution for giving to a structure on which is fixed a turbomachine the desired flexibility, and that this solution impacts the vibratory signature of the turbomachine in a desired manner, and without require a specific design of all or part of the structure, said structure may be a test bench or an aircraft.

More particularly, according to a first aspect, the invention consists of an interchangeable support for fixing a turbomachine, characterized in that it comprises a main body which comprises at least two planar faces, a first face adapted for attachment to an external structure and a second face adapted for attachment to the turbomachine, said body being hollow and having a cavity which comprises two ends and which extends perpendicularly to a main direction of elongation of said main body and which opens out on both sides; other of said thereof, said cavity being filled with a liquid and being closed at both ends by a flexible partition, said support further comprising a damping keel which protrudes inside the cavity in s extending rigidly from one of the walls of the main body, said damping keel and the liquid participating in the damping of deformations created on the main body by the turbomachine when it is mounted on the structure.

Such a support makes it possible to adapt the dynamic situation of the structure to the turbomachine by a simple adaptation of the support by varying well-defined parameters, so that the structure no longer needs to be adapted in a specific way to the turbomachine. Such a solution allows substantial time savings in development, and therefore an associated saving.

According to an additional feature, the main body has a cylindrical outer shape defined by a generator which is perpendicular to the main direction of elongation of the main body.

According to an additional feature, the main body is made of an anisotropic material so as to reinforce the rigidity of the main body in at least one preferred direction.

According to an additional characteristic, the liquid situated inside the cavity is an oil which is pressurized.

According to a particular characteristic, the damping keel is connected to the second face of the main body, and said damping keel comprises three plates each comprising a length and a width of which: two plates each have their length directed in the direction; main elongation, and each have their width perpendicular to said main direction of elongation, and said plates are perpendicular to each other along their width; - A plate has its length which is directed according to the cavity and its width which is perpendicular to the main direction of elongation and the cavity.

According to another characteristic, the damping keel is made of a material that is more rigid than the main body, so that the main body deforms before the damping keel when the turbomachine transmits loads to the support.

According to an additional characteristic, the second face of the main body comprises a flat platform which projects from the main body and which is adapted to be fixed to the turbomachine.

According to a particular characteristic, the main body comprises an upper wall which constitutes the first face, a lower wall which constitutes the second face, as well as two lateral walls which each connect one end of the upper wall to one end of the lower wall.

According to an additional feature, the lower wall and / or the side walls have a variable thickness, so as to give the desired flexibility to the main body.

According to another feature, the main body is parallelepiped, the lower wall and the upper wall being parallel, and the side walls are both perpendicular to the upper and lower walls.

According to a second aspect, the invention consists of a test bench of a turbomachine characterized in that it comprises a support according to one of the preceding characteristics, the support being fixed on the one hand to the test bench by the first face of the main body, and secondly to the turbomachine by the second face of said main body.

According to a third aspect, the invention consists of an aircraft comprising a turbomachine characterized in that it comprises a support according to the preceding characteristics, the support being fixed on the one hand to the aircraft by the first face of the main body, and on the other hand to the turbomachine by the second face of said main body.

DESCRIPTION OF THE FIGURES Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows, and with reference to the appended drawings, given as non-limiting examples and in which: FIG. 1 represents a perspective view of a support for fixing a turbomachine according to a first embodiment, this view not representing the flexible partitions which close the cavity; FIG. 2 represents the same view as FIG. 1 for which the flexible partitions which close the cavity are represented; FIG. 3 represents a perspective view of a damping keel according to a first embodiment; FIG. 4 represents a perspective view of a support according to a second embodiment, this view not showing the flexible partitions which close the cavity; FIG. 5 represents the same view as FIG. 4 for which the flexible partitions which close the cavity are represented; FIG. 6 represents a perspective view of a support according to a third embodiment, this view not representing the flexible partitions which close the cavity; FIG. 7 represents the same view as FIG. 6 for which the flexible partitions which close the cavity are represented; FIG. 8 represents a turbomachine which is fixed to a test bench, so as to locate the arrangement of the supports when they are used for fastening a turbomachine to a structure; FIG. 9 represents an embodiment in which the support is connected to a fastener.

DESCRIPTION OF ONE OR MORE EXAMPLES OF EMBODIMENTS

FIGS. 1 and 2 show a first embodiment of a support 1 for fixing a turbomachine for regulating the dynamic loads transmitted by the turbomachine, said support 1 being interchangeable.

The support 1 comprises a main body 2 which comprises at least two plane faces, a first face adapted for attachment to a structure (such as a test bench or wing of an aircraft), and a second face adapted for fixing. to the turbomachine. The support 1 comprises a length directed along a main direction of elongation, a width and a height.

In the first embodiment, the main body has a cylindrical outer shape defined by a generatrix which is perpendicular to the main direction of elongation of the main body 2. Here is meant by a cylindrical solid, a solid which is delimited by two strictly parallel planes and a surface formed by a set of straight lines parallel to a line called generatrix, the generatrix being perpendicular to the two planes.

In order to simplify the understanding of the geometry of the dynamic load support 1, there is shown a reference mark consisting of three axes which each define a direction. A first axis X is directed along the width of the main body 2, a second axis Y is directed along the length of the main body 2 (and therefore also in the main direction of elongation), and a third axis Z is directed according to the height of the main body 2.

More specifically, according to the first embodiment, the main body 2 is a parallelepiped which comprises an upper wall 21 which constitutes the first face, a lower wall 22 which constitutes the second face and which is located facing the upper wall 21, and two side walls 23 which are located facing each other and which each connect one end of the upper wall 21 to one end of the lower wall 22. In the first embodiment, the upper walls 21 and lower 22 are parallel, and the side walls 23 are parallel to each other and are perpendicular to the upper walls 21 and lower 22.

The first and second faces of the main body 2 can each be fixed to the structure or to the turbomachine by means of at least one fastener. Thus, the upper wall 21 and lower 22 can each be attached to the structure or the turbomachine via at least one stiff attachment piece. In order to be adapted to be fixed to the structure or to the turbomachine, the upper and lower walls 21 and 21 comprise fastening means, for example holes 7 which make it possible to fasten by bolting.

The support 1 also comprises a cavity 3 which is located inside the main body 2 and which extends along the axis X (and therefore perpendicular to the main direction of elongation). In addition, the cavity 3 extends along the generatrix of the main body 2. The cavity 3 opens on either side of the main body 2, the cavity 3 comprising two ends facing each other according to the X axis.

This geometry of the support 1 makes it possible to provide great flexibility to the main body 2 for displacements of the lower wall 22 over four of the six possible degrees of freedom. The six degrees of freedom for the displacements of the lower wall 22 being constituted by the three translational movements along each of the X, Y and Z axes, as well as by the three rotational movements along each of the X, Y and Z axes.

More precisely, this geometry of the support 1 makes it possible to bring great flexibility to the main body 2 for displacements of the lower wall 22 according to: a translation along the Z axis; a translation along the Y axis; a rotation along the axis X; and a rotation along the Y axis.

Thus, only the motions of the turbomachine causing movements of the lower wall 22 according to these four degrees of freedom will be amortized. Therefore, the orientation of the support 1 during the fixing of the turbomachine to the structure is adapted according to: on the one hand the charges created by the turbomachine which can be transmitted to the structure on which said turbomachine is fixed; - On the other hand the movements that transmit or the part (s) for fixing the support 1 to the turbomachine, the part (s) of attachment may not transmit certain movements depending on the type of connection.

The flexibility of the main body 2 can be adapted by varying the thickness of the upper wall 21, the lower wall 22, and / or the side walls 23. The flexibility of the main body 2 can also be varied by varying its length, its width and / or height.

The cavity 3 is closed by two flexible partitions 31 which are each located at one end of the cavity 3. The flexible partitions 31 are such that they can deform very easily when the main body 2 is subjected to compression and traction according to the Z axis, bending along the Y axis and bending along the X axis. Indeed, the main body 2 deforms very much for these mechanical stresses, and deforms very little for other mechanical stresses. Thus, the flexible partitions 31 may be metal membranes or membranes of a plastic sufficiently resistant to withstand the pressure inside the cavity 3. The flexible partitions 31 may be assembled to the main body 2 for example by gluing or by welding.

The cavity 3 is also filled with a liquid, the liquid preferably being an oil which is pressurized.

The support 1 also comprises a damping keel 4 which is located inside the cavity 3 protruding inside thereof, and whose function is to dampen the deformations of the main body 2 when the it is subjected to loads from the turbomachine to which said support 1 is fixed. The damping of the deformations brought by the damping keel 4 is created by the friction caused by the displacement of the damping keel 4 in the liquid inside the cavity 3. Thus, so as to vary the damping it is possible to vary the viscosity of the liquid, the temperature of the liquid, and the pressure at which it is inside the cavity 3. In a preferential manner, the damping keel 4 is fixed on the second face of the integral body 2, so as to be secured to the fastening with the turbomachine, the deformations of the main body 2 being due to the charges transmitted by the turbomachine. Thus, for the embodiments that are described in this application, the damping keel 4 is fixed on the lower wall 22, the second face being constituted by the lower wall 22 in the embodiments presented in this application.

An advantage of such a support 1 is that it has good flexibility for the desired mechanical stresses (Z-axis pulls and compressions, X-axis bends and Y-axis bends). ), that it is able to withstand the loads transmitted by the turbomachine (of the order of a few tens of tons), and that it is compact. The small footprint is particularly interesting because it makes it possible to compensate, at least in part, the increase in the size of turbomachines of new generations.

As shown in FIG. 3, the damping keel 4 comprises three rectangular plates 41, 42, 43 which each comprise a length and a width, the length of a plate being longer than the width. The damping keel 4 also includes a foot 44 which connects the plates 41, 42 and 43 to the main body 2. In the embodiment shown in Figure 3, the foot 44 is also constituted by a rectangular plate. A first plate 41 and a second plate 42 each have their length directed in the main direction of elongation, and are perpendicular to each other in their width. A third plate 43 has its length directed along the cavity 3 and its width perpendicular to the main direction of elongation. The foot 44 has its width directed in the main direction of elongation and has its length perpendicular to the main direction of elongation.

By locating with respect to the X, Y and Z axes, the first plate 41 has its length which is directed along the Y axis and its width which is directed along the X axis, the second plate 42 has its length which is directed along the axis Y and its width which is directed along the axis Z, the third plate 43 has its length which is directed along the axis X and its width which is directed along the axis Z, and the foot 44 has its length which is directed along the Z axis and the width which is directed along the Y axis.

The first plate 41 makes it possible to damp the movements in translation of the lower wall 22 along the Z axis. The second plate 42 makes it possible to damp the translational movements along the X axis. The third plate 43 makes it possible to damp the displacements. in translation along the axis Y, as well as the displacements in rotation along the axis X. In this embodiment, the foot 44 serves to damp the same displacements as the second plate 42.

As illustrated in FIG. 9, when the support 1 is connected to a stiffening piece 8 by its lower wall 22, the center of the rotational displacements of said lower wall 22 is a point G which is situated on the fastening piece 8, and not on the lower wall 22. Depending on the position of the center of the rotational movements, the plates 41, 42, 43 and the foot 44 which constitute the damping keel 4 do not have the same influence on the damping of the rotational movement of the support 1. Thus, it is possible to adapt the plates 41, 42, 43 and the foot 44 constituting the damping keel 4 in order to damp the desired rotational movements according to the position of the center of displacements. rotation. It is thus possible to modify the number of plates 41, 42, 43 and / or their shape. It is also possible to modify the shape of the foot 44 in order to play on the rotational movements thus damped. It is of course obvious that it is also possible to choose the movements in translation damped by the damping keel 4 by modifying the plates 41, 42, 43 and the foot 44 (for example by modifying their number and / or their shape ).

In order to increase the effectiveness of the damping keel 4, the damping keel 4 is made of a material that is more rigid than the main body 2, so that when the main body 2 is subjected to a pull or a compression along the z axis, or bending about the X axis, or bending around the Y axis, the main body is deformed while the keel damping 4 tends to keep its original shape.

According to a variant of the invention, the main body 2 is made of an anisotropic material, so as to reinforce the rigidity of said main body 2 in at least one preferred direction. The choice of the direction according to which the rigidity of the main body 2 is reinforced makes it possible to modify the dynamic situation of the support 1 (the modes of vibration of the support 1 and its structural damping).

According to a second embodiment shown in Figures 4 and 5, the side walls 23 of the main body 2 are not parallel. More specifically, a cross section of the main body 2 along the X axis is any trapezoidal shape, the upper wall 21 and the lower wall 22 being parallel, and the length of the side walls 23 being directed in a direction having a component according to the Y and Z axes.

Such an embodiment makes it possible to modify the dynamic situation of the support 1. In fact, by modifying the direction in which the length of the lateral walls 23 is directed, the vibration modes of the structure and its structural damping are modified.

According to a third embodiment shown in Figures 6 and 7, the thickness of the side walls 23 and the lower wall 22 is variable. More specifically, the thickness of the side walls 23 varies along their length so as to be greater near the upper wall 21 than near the lower wall 22.

According to one possible variant, only the side walls 23 have a variable thickness. According to another possible variant, only the lower wall 22 has a variable thickness.

The fact that the thickness of the side walls 23 and / or the thickness of the lower wall 22 is variable makes it possible to adapt the flexibility of the main body 2, the way in which the thickness varies being chosen so as to obtain the desired flexibility.

It is preferable to keep the thickness of the first face of the main body 2 (which is the upper wall 21 for all the embodiments presented) constant, since the deformations of the main body 2 must preferably be located at the level of the main body 2. other parts of the main body 2 (for example at the side walls 23 and the lower wall 22 for the embodiments presented in this application).

In addition, in the third embodiment, as shown in FIGS. 6 and 7, the lower wall 22 comprises a flat platform 24 which protrudes outside the main body 2. The platform 24 is obtained by a localized increase of the thickness of the lower wall 22. This platform 24 has the function of ensuring good attachment with the turbomachine on the one hand, and on the other hand to ensure rigidity of the lower wall 22 at the means of fixing the turbine engine. Thus, the platform 24 is adapted to be fixed to the turbomachine and thus comprises fastening means, such as holes 7 to ensure a connection by bolting with the turbomachine.

Finally, as represented in FIG. 8, the support 1 is disposed at the interface of a structure (here a test bench 6) and a turbomachine 5. More precisely, in the example illustrated in FIG. 8 , the turbomachine 5 is fixed to the test bench 6 by two separate fasteners. Each attachment comprises a support 1 which makes it possible to regulate the dynamic loads transmitted by the turbomachine 5. Thus, the same test bench 6 can be used for another turbomachine 5 (for example a turbomachine of the same model but whose elements have been changed) without having to be adapted. Indeed, only the supports 1 must be replaced by supports 1 whose dynamic situation is adapted to the other turbomachine 5. The adaptation of a support 1 is actually much simpler and much less expensive than the modification of a test bench 6. In addition, the support 1 having a small footprint, it is easy to have a stock of interchangeable supports 1 which are different and which are each adapted for different turbomachines 5.

As indicated above, the structure on which the turbomachine is fixed via the support 1 can also be an aircraft, such as an aircraft. Indeed, in the case where a turbomachine 5 is fixed under the wing of an aircraft, a fastening of the turbomachine 5 may comprise a support 1, this support 1 on the one hand offering the advantage of one to ensure fixing a desired flexibility and an impact on the vibratory signature of the turbomachine 5 mastered; and on the other hand offers a compact fixing solution.

According to one possible variant, the main body 2 may comprise non-parallel lateral walls 23, and it may also comprise a platform 24.

According to another possible variant, the main body 2 may comprise non-parallel side walls 23 and have a lower wall 22 and / or its side walls 23 which have a variable thickness.

Finally, the first and second faces of the main body 2 may not be parallel, in order to adapt the shape of the support 1 to the fastening stresses of the turbomachine 5.

Claims (12)

Interchangeable support (1) for attaching a turbomachine (5), characterized in that it comprises a main body (2) which comprises at least two plane faces, a first face adapted for attachment to a structure ( 6) external and a second face adapted for attachment to the turbomachine (5), said main body (2) being hollow and having a cavity (3) which comprises two ends and which extends perpendicularly to a main direction of elongation of said main body (2) and which opens on either side thereof, said cavity (3) being filled with a liquid and being closed at its two ends by a flexible partition (31), said support (1 ) further comprising a damping keel (4) projecting into the cavity (3) extending rigidly from a wall of the main body (2), said damping keel (4) and the liquid involved in the damping of the deformations created on the main orps (2) by the turbomachine (5) when it is mounted on the structure (6). 2. Support (1) according to claim 1, characterized in that the main body (2) has a cylindrical outer shape defined by a generator which is perpendicular to the main direction of elongation of the main body (2). 3. Support (1) according to claim 1 or 2, characterized in that the main body (2) is made of an anisotropic material so as to reinforce the rigidity of said main body (2) in at least one preferred direction. 4. Support (1) according to one of the preceding claims, characterized in that the liquid located inside the cavity (3) is an oil which is pressurized. 5. Support (1) according to one of the preceding claims, characterized in that the damping keel (4) is connected to the second face of the main body (2), said damping keel (4) comprising three plates (41, 42, 43) each comprising a length and a width and of which: two plates (41, 42) each have their length directed in the main direction of elongation, and each have their width perpendicular to said main direction of elongation, and are perpendicular to each other according to their width; - a plate (43) has its length which is directed according to the cavity and its width which is perpendicular to the main direction of elongation and the cavity. 6. Support (1) according to one of the preceding claims, characterized in that the damping keel (4) is made of a material more rigid than the main body (2), so that main body (2) is deforms before the damping keel (4) when the turbomachine (5) transmits charges to the support (1). 7. Support (1) according to one of the preceding claims, characterized in that the second face of the main body (2) comprises a flat platform (24) which projects outside the main body (2) and which adapted to be attached to the turbomachine (5). 8. Support (1) according to one of the preceding claims, characterized in that the main body comprises an upper wall (21) which constitutes the first face, a lower wall (22) which constitutes the second face, and two walls side members (23) each connecting one end of the upper wall (21) to one end of the lower wall (22). 9. Support (1) according to claim 8, characterized in that the lower wall (22) and / or the side walls (23) have a variable thickness, so as to give the desired flexibility to the main body (2). 10. Support (1) according to one of claims 8 or 9, characterized in that the main body (2) is parallelepiped, the lower wall (21) and the upper wall (22) being parallel, and the side walls ( 23) being both perpendicular to the upper (21) and lower (22) walls. 11. Test bench (6) of a turbomachine (5) characterized in that it comprises a support (1) according to one of claims 1 to 10, the support (1) being fixed on the one hand to test bench (6) by the first face of the main body (2), and secondly to the turbomachine (5) by the second face of said main body (2). 12. Aircraft comprising a turbomachine (5) characterized in that it comprises a support (1) according to one of claims 1 to 10, the support (1) being fixed on the one hand to the aircraft by the first side the main body (2), and secondly to the turbomachine (5) by the second face of said main body (2).