AXIAL DISPLACEMENT MEASUREMENT SYSTEM IN AN AIRCRAFT TURBOMACHINE

Abstract

The invention relates to a system (400) for measuring axial displacements in an aircraft turbomachine, comprising a rotor part (200) rotatable about an axis (X), and a stator part (300) having an axially projecting portion (210) separated by a given axial distance (D) from an element (310) carried by the stator part (300) and located axially opposite this axially projecting portion (210). The rotor part (200) is capable of moving or expanding during operation along the axis (X), which generates variations in said distance (D). According to the invention, the measuring system (400) is capable of detecting and measuring these variations and comprises a wear element (320) carried by said element (310) and configured to cooperate by friction with said end (210). (Shorthand figure: Figure 2)

Description

Title of the invention: SYSTEM FOR MEASURING AXIAL DISPLACEMENTS IN AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates in particular to a system for measuring axial displacements in an aircraft turbomachine and an aircraft turbomachine comprising such a measurement system. Technical background

[0002] As is known, a turbomachine is intended to provide the thrust necessary for the propulsion of an aircraft. It classically comprises, from upstream to downstream with respect to the direction of gas flow within the turbomachine, a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, and an exhaust nozzle.

[0003] Controlling the axial clearances of the turbomachine, i.e., the clearances in the longitudinal direction of the turbomachine, is important. This control is particularly important downstream of the turbomachine, notably for optimizing low-pressure turbine clearances (blower doors, turbomachine length), and for dimensioning bearing raceways with rolling elements such as rollers or balls, seal raceways, abradable lengths of labyrinth seals, non-contact clearances downstream of the engine, etc.

[0004] Several solutions exist for measuring these axial clearances. One involves the use of wear indicators. This solution specifically involves positioning felt pads at relevant locations on the turbomachine, determined by analysis, and visually measuring the wear at the end of a test campaign. This solution thus makes it possible to determine the minimum clearance during operation, but not to associate it with the moment of maximum wear because the clearances are not measured in real time but only at the end of the test campaign.

[0005] A second solution involves using X-rays to measure axial clearances. This method allows for real-time determination of axial clearances, but its implementation is expensive and requires an isolated and protected implementation environment.

[0006] The technical background includes in particular document FR-A1-3 072 413, which describes the radial wear of an abradable turbomachine element, this radial wear being able to be visualized by endoscopy.

[0007] The present invention proposes a simple, effective and economical solution to the need mentioned above. Summary of the invention

[0008] The invention relates to a system for measuring axial displacements in an aircraft turbomachine. This measuring system comprises a rotor part that rotates about an axis, and a stator part mounted coaxially upstream or downstream of the rotor part. The rotor part has an axially projecting portion separated by a given axial distance from an element carried by the stator part and located axially opposite this axially projecting portion. The rotor part is capable of moving or expanding during operation along the axis, which causes variations in said distance. According to the invention, the measuring system is capable of detecting and measuring these variations and comprises a wear element carried by said element and configured to cooperate by friction with said axially projecting portion. This wear element comprises:

[0009] - a body made of abradable material carried by said element and comprising a face of wear located axially opposite the axially projecting part which is capable of coming into contact with this face and machining the body axially by friction, and

[0010] - at least two tubes formed in the body or mounted in the body, the tubes comprising longitudinal ends which are oriented parallel to each other and to said axis and towards said wear face, these longitudinal ends being closed by thicknesses of material of said body which are different from each other so that machining of the body by the axially projecting part successively causes the unblocking of the longitudinal ends of the tubes and the establishment of fluid communication from the inside of the tubes with the outside of the element, and

[0011] - measuring sensors connected respectively to said tubes and which are configured to monitor at least one physical parameter and to detect a variation of said at least one physical parameter corresponding to said fluidic communication.

[0012] The measurement system of the invention is simple to implement in the turbomachine, inexpensive, and allows for the real-time measurement of axial clearances between the rotor and stator components. Compared to existing solutions (particularly the X-ray solution), the invention offers the advantage of being less expensive, easier to install, and does not require positioning in an isolated environment. Furthermore, compared to the solution involving visual analysis of wear indicators, it has the advantage of being able to determine the precise moments at which wear occurs, especially without having to wait for the end of a test campaign. Knowing the precise moments at which wear occurs allows in particular to identify the critical maneuvers which are dimensioning for axial games and in particular to recalibrate the models for calculating displacements.

[0013] The measurement system according to the invention may comprise one or more of the following features, taken individually or in combination with each other: • the longitudinal ends of the tubes are arranged next to each other in a circumferential direction, or in a radial direction;

[0014] — the tubes each have a general L-shape; • the tubes each comprise a radially oriented part having an internal or external radial end, and an axially oriented part having the corresponding longitudinal end; • the longitudinal ends of the tubes are arranged in a stepped pattern; This means that these ends are not aligned in the same plane perpendicular to the axis but are instead axially offset from each other so as to form steps; • the sensors are pressure sensors and / or temperature sensors;

[0015] — the sensors are housed or located at the radial ends of the tubes;

[0016] - the system includes branch tubes which respectively connect the tubes to a first enclosure of a turbomachine module which is at a first pressure, and said body is located in a second enclosure of the turbomachine module which is at a second pressure greater than the first pressure — the second pressure is greater than the first pressure; • said axially projecting part of the part is coated with a wear-resistant layer;

[0017] — in the absence of wear on the body, the longitudinal ends of the tubes are invisible; • the stator part is a compressor rectifier or a turbine distributor or a housing, structural or not, and the rotor part is a compressor or turbine wheel; • said axially projecting part of the rotor part is an annular spoiler of the wheel, and said element of the stator part is a sealing ring of the rectifier or distributor or housing.

[0018] The invention also relates to a turbomachine module, comprising at least one measuring system as described above.

[0019] The invention further relates to an aircraft turbomachine, comprising at least one measuring system as described above. Brief description of the figures

[0020] Other features and advantages will become apparent from the following description of a non-limiting embodiment of the invention with reference to the accompanying drawings in which:

[0021] [Fig-1] [Fig.1] is a schematic axial cross-sectional view of a turbomachine aircraft,

[0022] [Fig.2] [Fig.2] is a schematic axial cross-sectional view of part of a measuring system according to the invention forming part of the turbomachine of [Fig.1],

[0023] [Fig.3] [Fig.3] is a view similar to [Fig.2] showing an alternative embodiment of the invention,

[0024] [Fig.4] [Fig.4] is a larger-scale schematic view of [Fig.2], and illustrates one embodiment of the invention,

[0025] [Fig.5] [Fig.5] is a circumferential cross-sectional view of a wear element of the measuring system of the invention,

[0026] [Fig. 6a-6c] Figures 6a-6c illustrate the wear element of the [Fig. 5] at different wear levels. Detailed description of the invention

[0027] Referring to [Fig. 1], we see a turbomachine 1, which conventionally comprises a fan S, a low-pressure compressor 1a, a high-pressure compressor 1b, a combustion chamber 1e, a high-pressure turbine Id, and a low-pressure turbine 1e. The high-pressure compressor 1b includes rotors connected to the high-pressure turbine Id by a high-pressure shaft 5 or HP. The low-pressure compressor 1a includes rotors connected to the low-pressure turbine 1e by a low-pressure shaft 4 or BP. The turbomachine 1 is thus of the twin-shaft type, HP and BP, although this example is not limiting. The blower S is, for its part, carried by a blower shaft 3 which is connected here by a reducer 7 to the BP shaft 4. The invention also applies to a turbomachine configuration 1 without reducer, that is to say with a direct drive of the blower shaft 3 by the BP shaft 4.

[0028] The HP and BP shafts extend along an X axis which is the axis of rotation of the turbomachine 1. In the following description, the notions of longitudinal or radial, and of inside or outside, are relative to this X axis.

[0029] The turbomachine 1 includes structural housings. The HP body is held by two structural housings: the inter-compressor housing and the inter-turbine housing, and the LP body is held by at least two structural housings: the intermediate housing 2 and the inter-turbine housing and / or the exhaust housing 6.

[0030] The intermediate housing 2 supports bearings of the turbine shaft BP 4 which are housed in a front or upstream enclosure denoted El. The exhaust housing 6 supports bearings of the turbine shaft BP 4 which are housed in a rear or downstream enclosure denoted E2.

[0031] The enclosures El, E2 are generally partially delimited by bearing supports. These bearings are lubricated with oil to optimize their operation and dissipate the thermal energy produced.

[0032] Seals are positioned to ensure the sealing of the enclosures El, E2. The bearings may be roller or ball bearings. The bearings and / or seals form the interface between the stators and the rotors.

[0033] The turbomachine 1 also includes a measuring system 400 according to the invention as illustrated in particular in Figures 2, 3 and 4. Such a measuring system 400 comprises a rotor part 200 movable in rotation about an axis, here the X axis, and a stator part 300 mounted coaxially upstream of the rotor part 200. Alternatively, the stator part 300 could be mounted downstream of the rotor part 200.

[0034] The stator component 300 can, for example, be a compressor rectifier, a turbine distributor, or a housing (e.g., an inter-turbine housing), whether structural or not. The rotor component 200 can, in particular, be a compressor or turbine wheel. In the drawings, a turbine distributor is shown followed by a turbine wheel, but the invention applies by analogy to a compressor.

[0035] The rotor part 200 includes, for example, an axially projecting part 210 which is separated by a given axial distance D from an element 310. The axially projecting part 210 of the rotor part 200 is, for example, an annular spoiler of the compressor or turbine wheel.

[0036] The element 310 is in particular carried by the stator part 300 and is in particular located axially opposite the axially projecting part 210. The element 310 of the stator part 300 can for example be a sealing ring of the compressor rectifier or of the turbine distributor.

[0037] During operation of the turbomachine, the rotor part 200 is likely to move or expand along the X axis, which can cause variations in the distance D. The variations in this distance D are representative of the variations in axial clearance between the rotor part 200 and the stator part 300.

[0038] According to the invention, the measuring system 400 is capable of detecting and measuring these variations. The measuring system 400 includes, in particular, a wear element 320. The wear element 320 is, in particular, carried by the element 310. The wear element 320 is, in particular, configured to cooperate by friction with the axially projecting part 210.

[0039] The wear member 320 may, for example, comprise a body 321 made of abradable material carried by the element 310. The body 321 may, for example, be parallelepiped in shape. The body 321 may, in particular, protrude from the element 310, especially axially.

[0040] The body 321 may have a wear face 311 located axially opposite the axially projecting part 210. The axially projecting part 210 is able to come into contact with the wear face 311 and to machine axially the body 321 by friction, in particular during the operation of the turbomachine and the rotation of the rotor part 200.

[0041] The axially projecting part 210 of the rotor part 200 in particular projects outward from the rest of the rotor part 200, especially axially.

[0042] The axially projecting part 210 of the rotor part 200 can, for example, be coated with an anti-wear layer.

[0043] Furthermore, the wear member 320 may comprise at least two tubes 322a, 322b, and in particular three tubes 322a, 322b, 322c. The tubes 322a, 322b, 322c are, for example, radially housed in the stator part 300, here a distributor. The tubes 322a, 322b, 322c are formed, in particular, in the body 321 or mounted in the body 321. The tubes 322a, 322b, 322c have longitudinal ends 324a, 324b, 324c which are, for example, oriented parallel to each other and to the X-axis and which are, in particular, oriented towards the wear face 311.

[0044] The longitudinal ends 324a, 324b, 324c are closed by thicknesses 326a, 326b, 326c of material from the body 321. The thicknesses 326a, 326b, 326c represent the distance which separates the longitudinal ends 324a, 324b, 324c from the wear face 311 and therefore from the axially projecting part 210.

[0045] The thicknesses 326a, 326b, 326c opposite the tubes 322a, 322b, 322c are in particular different from each other so that the machining of the body 321 by the axially projecting part 210 causes successively the unblocking of the longitudinal ends 324a, 324b, 324c of the tubes 322a, 322b, 322c and the fluidic communication of the interior of the tubes 322a, 322b, 322c with the exterior of the element 310.

[0046] The longitudinal ends 324a, 324b, 324c of the tubes 322a, 322b, 322c are arranged side by side in a circumferential direction. Alternatively, the longitudinal ends 324a, 324b, 324c of the tubes 322a, 322b, 322c may be arranged side by side in a radial direction.

[0047] The tubes 322a, 322b, 322c each have, for example, a general L-shape. The tubes 322a, 322b, 322c each include, in particular, a radially oriented portion 325 which has a radial end 323, either internal or external. The tubes 322a, 322b, 322c each include in particular an axially oriented part 327 which includes the corresponding longitudinal end 324a, 324b, 324c.

[0048] The wear member 320 may include measuring sensors 401a, 401b, 401c connected respectively to the tubes 322a, 322b, 322c and which are configured to monitor at least one physical parameter P and to detect a variation of said at least one physical parameter P corresponding to the fluidic communication of the inside of the tubes 322a, 322b, 322c with the outside of the element 310.

[0049] Each sensor 401a, 401b, 401c is located in or connected to its own analysis unit. The measuring sensors 401a, 401b, 401c are, in particular, pressure sensors in the case where the controlled physical parameter P is pressure. Other parameter / sensor pairs could be used within the scope of the present invention, for example, the temperature / temperature sensor pair. Indeed, the rapid increase in pressure when one of the tubes 322a, 322b, 322c is opened also results in a relatively rapid increase in the air temperature in the tube 322a, 322b, 322c. The invention thus provides for the use of temperature sensors, either instead of or in addition to pressure sensors.

[0050] As can be seen in particular in [Fig.2], the sensors 401a, 401b, 401c are for example housed outside the engine, in particular in a compartment of a nacelle of the turbomachine (for example a fan compartment), that is to say in particular outside a flow channel in which the rotor part 200 is located. The sensors 401a, 401b, 401c are housed in particular at the radial end 323 of the tubes 322a, 322b, 322c. Alternatively, tubes 322a, 322b, 322c lead to sensors 401a, 401b, 401c, in particular and as illustrated in [Fig.2], the radial end 323 of tubes 322a, 322b, 322c lead to sensors 401a, 401b, 401c.

[0051] The tubes 322a, 322b, 322c, in particular the radial end 323 of the tubes 322a, 322b, 322c, terminate in particular in a compartment housing the sensors 401a, 401b, 401c.

[0052] The tubes 322a, 322b, 322c are connected and in fluidic communication with a first enclosure 220 of a turbomachine module 100. The sensors 401a, 401b, 401c are located in this enclosure 220. In particular, the radial end 323 of the tubes 322a, 322b, 322c is connected with the first enclosure 220. The first enclosure 220 has a first pressure PL.

[0053] The body 321 is located in a second enclosure 230 of the turbomachine module 100. The second enclosure 230 has a second pressure P2 that differs from the first pressure PL. The second pressure P2 is, in particular, higher than the first pressure PL. The difference between the second pressure P2 and the first pressure PL is large enough to allow the sensors 401a, 401b, 401c to detect the fluidic connection while being small enough to avoid a collapse of the tubes 322a, 322b, 332c on themselves.

[0054] The turbomachine module 100 includes, for example, all or part of the turbomachine 1. By way of example, and as illustrated in [Fig.2], the first enclosure 220 may be located outside the engine, in particular in a compartment of a nacelle of the turbomachine (for example a fan compartment), that is to say in particular outside a flow channel in which the rotor part 200 is located.

[0055] Alternatively, and as shown in [Fig. 3], the first chamber 220 can be located in an inter-vein compartment (referred to as the "Core zone"). In this case, the measuring system 400 includes tapping tubes 328a, 328b, 328c, in particular of small cross-section, connecting the inside of tubes 322a, 322b, 322c to the first chamber 220. This allows the inside of tubes 322a, 322b, 322c to be subjected to the pressure of the first chamber 220, which is higher than that of the chamber 230, in order to prevent the collapse of tubes 322a, 322b, 322c. Alternatively, the tapping tubes 328a, 328b, 328c could connect the tubes 322a, 322b, 322c to a separate enclosure from the first enclosure 220 and for example an enclosure located upstream of the second enclosure 230.

[0056] In this configuration, the sensors 401a, 401b, 401c will then detect a drop in pressure when the longitudinal end of the tubes 322a, 322b, 322c is unblocked.

[0057] In the example embodiment of [Fig.2], the first enclosure 220 is in particular located around the second enclosure 230. In the example embodiment of [Fig.3], the first enclosure 220 is in particular located upstream of the second enclosure 230.

[0058] As illustrated in [Fig. 5], in the absence of wear on the body 321, the longitudinal ends 324 of the tubes 322a, 322b, 332c are invisible and are therefore sealed against the fluid present outside the tubes 322a, 322b, 332c. The sensors 40a, 401b, 401c then return a zero signal.

[0059] During the rotation of the rotor part 200, the axially projecting portion 210 in contact with the wear element 320 wears the latter, starting with the wear face 311. The axially projecting portion 210 wears the wear element 311, and in particular the axial thickness 326a, 326b, 326c, until at least one of the tubes 322a, 322b, 322c is unblocked, thus bringing it into fluidic contact with the exterior of the element 310, notably with the second chamber 230. The pressure PI present inside the tubes 322a, 322b, 322c before unblocking, in particular the asbestos pressure, being different from the pressure P2 present in the second chamber 230, the sensor 401a, 401b, 401c positioned in the tube 322a, 322b, 322c outlet will detect a variation of the parameter P that it monitors during the fluidic communication. This increase can be abrupt, particularly in the embodiment of [Fig.2] which does not include the tapping tubes. This information regarding the variation of the parameter P is subsequently analyzed, and it is deduced that the material of the thickness 360a, 360b, 360c which separated the tube 322a, 322b, 322c before it was opened from the wear face 311 has been worn by the axially protruding part 210 and that the rotor part 200 has therefore moved axially by this distance, thus allowing the axial variation of the rotor part 200 relative to the stator part 300 to be deduced, and therefore the axial clearance.

[0060] When the tube 322a, 322b, 322c is unblocked, the axially projecting part 210 ensures that the tube 322a, 322b, 322c is in fluidic communication with the outside of the element 310. Indeed, without this axially projecting part 210, the rotor part 200 would itself risk acting as a plug for the tube 322a, 322b, 322c and thus disrupting the measurement.

[0061] If the measurement frequency of sensors 401a, 401b, 401c is sufficient relative to the time it takes for the first pressure PI to change to the second pressure P2, a measurement of the gradient (temporal variation) of the parameter P may suffice. Indeed, the gradient is relatively small as long as the thickness 360a, 360b, 360c is not worn, then increases sharply when one of the tubes 322a, 322b, 322c is unblocked, and becomes relatively small again once the sensor 401a, 401b, 401c measures the second pressure P2 of the second chamber 230. If both the criterion of the first pressure PI being greater than a first threshold and the parameter gradient being greater than a second threshold are applied, the detection of the unblocking of tube 322a, 322b, 322c is even more reliable.

[0062] As can be seen in particular in Figures 5, 6a, 6b, and 6c, the longitudinal ends 324a, 324b, 324c of the tubes 322a, 322b, 322c are, for example, arranged in a stepped pattern, following a staggered arrangement determined in particular by displacement analyses. Thus, the axial thicknesses 326a, 326b, 326c associated with the tubes 322a, 332b, 322c are different from one another. It is understood here that the axial distance separating the axial ends 324a, 324b, 324c of the tubes 322a, 322b, 322c from the wear face 311 and therefore from the axially projecting part 210 is different for each of the tubes 322a, 322b, 322c.

[0063] Thus, during the rotation of the rotor part 200, the axially projecting portion 210 wears down the body 321 until it initially eliminates (Figure 6a) the material contained in the thickness 326a opposite the first tube 322a. The first tube 322a is then connected fluidically to the exterior of the element 310, i.e., to the second chamber. A first 401a of the sensors 401a, 401b, 401c positioned in the first tube 322a then captures the difference in value of the first pressure PI relative to the second pressure P2, and it is possible to deduce the axial variation of the rotor part 200 vis-à-vis the stator part 300. This variation corresponds to the thickness 326a.

[0064] The axially projecting portion 210 subsequently wears down the body 321 until, in a second step (Figure 6b), it removes the material contained in the thickness 326b opposite the second tube 322b. The second tube 322b is then connected fluidically to the exterior of the element 310, i.e., to the second enclosure. A second sensor 401b of the sensors 401a, 401b, 401c, positioned in the second tube 322b, then captures the difference in value between the first pressure PI and the second pressure P2, and it is possible to deduce from this the additional axial variation of the rotor part 200 relative to the stator part 300. This variation corresponds to the sum of the thicknesses 326a and 326b.

[0065] The axially projecting portion 210 subsequently wears down the body 321 until, in a third step (Figure 6c), it removes the material contained in the thickness 326c opposite the third tube 322c. The third tube 322c is then connected fluidically to the exterior of the element 310, i.e., to the second enclosure. A third sensor 401c of the sensors 401a, 401b, 401c, positioned in the third tube 322c, then captures the difference in value between the first pressure PI and the second pressure P2, and it is possible to deduce from this the additional axial variation of the rotor part 200 relative to the stator part 300. This variation corresponds to the sum of the thicknesses 326a, 326b, and 326c.

Claims

1. Demands A system (400) for measuring axial displacements in an aircraft turbomachine (1), said measuring system (400) comprising a rotor part (200) rotatable about an axis (X), and a stator part (300) mounted coaxially upstream or downstream of the rotor part (200), the rotor part (200) having an axially projecting portion (210) which is separated by a given axial distance (D) from an element (310) carried by the stator part (300) and which is located axially opposite this axially projecting portion (210), the rotor part (200) being capable of moving or expanding during operation along the axis (X), which generates variations in said distance (D), characterized in that the measuring system (400) is capable of detecting and measuring these variations and comprises a wear element (320) carried by said element (310) and configured to cooperate by friction with said axially projecting part (210),this wear part (320) comprising: - a body (321) made of abradable material carried by said element (310) and comprising a wear face (311) located axially opposite the axially projecting part (210) which is capable of coming into contact with this face (311) and of axially machining the body (321) by friction, and - at least two tubes (322a, 322b, 322c) formed in the body (321) or mounted in the body (321), the tubes (322a, 322b, 322c) having longitudinal ends (324a, 324b, 324c) which are oriented parallel to each other and to said axis (X) and towards said wear face (311), these longitudinal ends (324a, 324b, 324c) being closed by thicknesses (326a, 326b, 326c) of material of said body (321) which are different from each other so that machining of the body (321) by the axially projecting part (210) successively causes the longitudinal ends (324a, 324b, 324c) of the tubes (322a, 322b, 322c) and the fluidic communication of the interior of the tubes (322a, 322b, 322c) with the exterior of the element (310), and - measuring sensors (401a, 401b, 401c) connected respectively to said tubes (322a, 322b, 322c) and which are configured to monitor at least one physical parameter (P) and to detect a variation of said at least one physical parameter (P) corresponding to said fluidic communication.

2. System (400) according to claim 1, wherein the longitudinal ends (324a, 324b, 324c) of the tubes (322a, 322b, 322c) are arranged next to each other in a circumferential direction, or in a radial direction.

3. System (400) according to claim 1 or 2, wherein the tubes (322a, 322b, 322c) each comprise an axially oriented part (327) having the corresponding longitudinal end (324a, 324b, 324c).

4. System (400) according to any one of the preceding claims, wherein the longitudinal ends (324a, 324b, 324c) of the tubes (322a, 322b, 322c) are arranged in a stepped pattern.

5. System (400) according to any one of the preceding claims, wherein the sensors (401a, 401b, 401c) are pressure sensors and / or temperature sensors.

6. System (400) according to any one of the preceding claims, comprising tapping tubes which respectively connect the tubes (322a, 322b, 322c) to a first enclosure (220) of a turbomachine module (100) which is at a first pressure (PI), and said body (321) is located in a second enclosure (230) of the turbomachine module (100) which is at a second pressure (P2) higher than the first pressure (PI).

7. System (400) according to any one of the preceding claims, wherein said axially projecting part (210) of the part (200) is coated with an anti-wear layer.

8. System (400) according to any one of the preceding claims, wherein the stator part (300) is a compressor rectifier or turbine distributor or housing, and the rotor part (200) is a compressor or turbine wheel.

9. System (400) according to the preceding claim, wherein said axially projecting part (210) of the rotor part (200) is an annular spoiler of the wheel, and said element (310) of the stator part (300) is a sealing ring of the rectifier or distributor.

10. Aircraft turbomachine, comprising at least one measuring system (400) according to one of the preceding claims.

Images