FR3043203A1 - DEVICE FOR MEASURING PARAMETERS OF AERODYNAMIC FLOW OF A TURBOMACHINE, TURBOMACHINE EQUIPPED WITH SUCH A DEVICE AND METHOD FOR MANUFACTURING A SEAL FOR SEALING SUCH A DEVICE - Google Patents

Abstract

The invention relates to a device (1) for measuring the parameters of an aerodynamic flow in a turbomachine (100), the device (1) comprising a measuring means (3) capable of measuring said parameters, a support (2) capable of to be fixed to a casing (101) of the turbomachine (100) and to carry said measuring means (3), the support (2) comprising a wall (5) provided with a main through opening (6) and at least one secondary through-hole opening into the main opening, the main opening (6) and the secondary through-hole (7) permitting passage of the measuring means during its assembly, a cover (4) configured so as to close or releasing the through opening (6) of the support, and a molded seal (14) removably arranged in the lumen (7).

Description

Device for measuring parameters of an aerodynamic flow of a turbomachine, turbomachine equipped with such a device and method of manufacturing a seal of such a device 1. Field of the invention

The present invention relates to the field of turbomachines, in particular aircraft turbomachines. In particular, it aims at a turbomachine with a dual flow in which a device for measuring certain parameters of the aerodynamic flow is installed. It also relates to a method of manufacturing a seal of this measuring device. 2. State of the art

As part of the development of turbomachines, they undergo a plurality of tests and tests to verify and validate their proper operation, their ability to maintain their integrity and performance. The validation of these tests and tests makes it possible to obtain a certification allowing their commissioning. In particular, during these tests and tests, measurements of certain aerodynamic flow parameters, such as pressure and temperature, are performed by means of an aerodynamic flow parameter measuring device installed in an area of the turbomachine where a flux. This flow measuring device comprises a support adapted to be fixed to the casing of the turbomachine and in which is inserted a measuring means for measuring parameters of a flow flowing in the turbomachine, generally secondary. When installing the device on the housing and to facilitate assembly, a game is provided between the measuring means and the support. This game causes flow leaks that cause a loss of performance of the turbomachine. In general, a flat seal is mounted between the measuring device and the housing. However, the integration of such a seal is complex and this seal does not seal leaks because the measuring means also comprises electrical connection means passing through passages through which the flow can escape. 3. Objective of the invention

The present applicant has therefore set itself the goal of developing a solution that would guarantee the performance of the turbomachine while ensuring rapid assembly and disassembly of the measuring device so as not to delay the time of the test period. and tests. 4. Presentation of the invention

This objective is achieved according to the invention by means of a device for measuring parameters of an aerodynamic flow in a turbomachine, the device comprising measuring means capable of measuring said parameters, a support capable of being fixed to a crankcase. the turbomachine and carrying said measuring means, the support comprising a wall provided with a main through opening and at least one secondary through-hole opening into the main opening, the main opening and the secondary through-hole allowing the passage measuring means during its assembly, a cover configured to close or release the through opening of the support, and a molded seal and removably arranged in the lumen.

Thus, this solution achieves the aforementioned objective. In particular, such a configuration makes it possible, on the one hand, to provide a simple and economical solution, and on the other hand, a saving of time in the assembly and disassembly of the measuring device. The gasket disposed in the light prevents leaks between the through opening in which the cover and the light are installed. Added to this is the fact that this seal is reusable from one test phase to another unlike a seal that would be injected directly into the light at each assembly and which would require scraping for his withdrawal.

According to one characteristic of the invention, the seal is at least partially covered by the cover. In this way, the holding in position is guaranteed by the cover.

According to one characteristic of the invention, the seal has an excess thickness configured so as to be crushed by the lid. Such a configuration allows during the assembly of this seal and in particular the cover which covers at least partially thereof, that the seal completely matches the shape of the light.

In particular, the cover comprises a flange at least partially covering the seal.

According to another characteristic of the invention, the extra thickness is between 0.5 mm and 3 mm so as to ensure sealing.

Advantageously, but not exclusively, the extra thickness is of the order of 1 mm. This makes it possible to completely fill the leaks.

In order to properly position the seal during assembly, it includes keying means.

According to another characteristic of the invention, the seal is made of a polymeric material.

Preferably, but not exclusively, the polymeric material is a polydimethylsiloxane. The invention also relates to a turbomachine with a double flow comprising a housing which extends along a longitudinal axis and which delimits a vein in which flows, the turbomachine comprise a device for measuring parameters of an aerodynamic flow according to the any of the above characteristics, the measuring device being attached to the casing of the turbomachine.

Thus the measuring device according to the invention is assembled and disassembled quickly without affecting the completion time of the tests and tests and engine performance are guaranteed. The invention also relates to a method of manufacturing a seal of the measuring device according to any one of the above-mentioned features. This method comprises the steps of using a mold obtained by stereolithography which comprises a first part and a second part each provided with complementary positioning means and forming the mold chamber, and the injection of a polymer into the chamber of the mold. mold. In this way, the mold manufacturing cycle and the release time of the seal pads is quick and easy.

According to a characteristic of this method, the positioning means comprise a groove and a rib extending respectively along connecting walls of the first part and the second part. This configuration makes it possible to avoid sagging between the first and second parts.

According to yet another characteristic of the method, the inner surface of each first and second part comprises a projection intended to form the polarizing means so as to guarantee the correct positioning of the seal in the light. 5. BRIEF DESCRIPTION OF THE FIGURES The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent on reading the following detailed explanatory description of embodiments of the invention. invention given by way of purely illustrative and non-limiting examples, with reference to the appended diagrammatic drawings in which:

FIG. 1 represents schematically in axial and partial section, an example of a double-flow turbomachine to which the invention applies;

FIG. 2 is a detailed view of a vein of the turbomachine according to FIG. 1 in which a device for measuring flow parameters according to the invention is installed;

Figures 3a to 3c are perspective views of different assembly steps of the measuring device according to the invention;

Figure 4 is a detailed view of a portion of the measuring device according to the invention;

Figure 5 shows secondary lights for receiving a seal according to the invention;

Figure 6 illustrates in perspective an example of a seal according to the invention;

Figure 7 is a sectional and partial view of a seal disposed in a light of the support of a measuring device according to the invention;

Figure 8 is a sectional view of the assembled measuring device according to the invention;

Figures 9 and 10 show embodiments of a mold for the manufacture of a seal. 6. Description of embodiments of the invention

FIG. 1 shows a sectional and partial view of a turbomachine 100, in particular a double flow turbomachine 100 according to the invention. This turbofan engine 100 generally comprises an outer casing 101 which extends substantially along a longitudinal axis X. The outer casing 101 comprises a gas generator 102 upstream of which is mounted a fan 103. In the present invention, and in general, the terms "upstream" and "downstream" are defined with respect to the flow of gas in the turbomachine 100. The turbomachine 100 comprises a primary stream 104 in which a primary flow flows through the gas generator 102 and a secondary vein 105 in which circulates a secondary flow between the outer casing 101 and an inner casing 106. In the secondary vein 105 are installed outlet guide vanes 107 known as the "Outlet Guide Vanes" (OGV) allowing to straighten the secondary flow. These output guide vanes 107 are fixed and mounted between the outer casing 101 and the inner casing 106.

A device 1 for measuring parameters of an aerodynamic flow is installed in the turbomachine 100 so as to establish a map of the pressures and temperatures of the flow flowing in the turbomachine 100. In particular, this flow measuring device 1 is installed in an area 108 situated just downstream of the exit guide vanes 107. The zone 108 is defined as being a measuring plane and makes it possible to have important parameters of performance of the turbomachine, such as a precise measurement of the blower torque / exit guide vanes.

With reference to FIGS. 2 to 5, the measuring device 1 comprises a support 2, measuring means 3 and a cover 4.

The support 2 is fixed to the outer casing 101 by means of fasteners not shown. The support 2 comprises a wall 5 extending in a plane AB substantially parallel to the plane of the housing 101 and which is provided with a main through opening 6 which passes through the wall 5 on either side in a direction perpendicular to the plane AB and here substantially radial to the longitudinal axis X. The opening 6 defines an inner wall 11 and here has a substantially rectangular shape. The support 2 also comprises at least one secondary lumen 7 opening into the main through opening 6. In FIG. 5, the lumen 7 also passes through the wall 5 on either side in the direction perpendicular to the plane AB (according to FIG. thickness of the wall). Here, the support 2 comprises three slots 7. Preferably, but not exclusively, the support is made of a metallic material.

The measuring means 3 is fixed to the support 2 which is intended to maintain it and carry it in the secondary vein 105 of the turbomachine 100 for carrying out the measurements of parameters. The measurement is called intrusive because it is performed directly in the stream. For this, the measuring means 3 comprises two legs 8 connected together on the one hand, by a base 9 and on the other hand, by a base 10. The legs 8 have an inverted L-shaped section. The base 9 is fixed to the support 2 via fasteners 27. In the example illustrated in Figure 4, these fasteners 4 here comprise four screws, two of which are placed on either side of a branch of lights 7 having an L shape, these L-shaped lights being on either side of a central light. Of course, other rapid and removable fixing means are possible for fixing the base 9 to the support 2. Each leg 8 extends into the secondary vein 105 in a plane transverse to the longitudinal axis X. The base 9 also comprises connecting members 28 to which are attached electrical connection means and / or electronic (not shown). These connecting members 28 each extend, when the device 1 is assembled, through a slot 7 of the support. In particular, the connection members 28 are, once the measuring means 3 mounted on the support 2, installed at the bottom of each branch of the L-shaped lights. For this purpose, the connection members 28 are flexible so as to facilitate their insertion into the lights 7. These connecting members 28 may comprise pins for feeding and / or transferring data to the measuring means 3.

The lid or plug 4 is configured to close or release the main through opening 6 of the support 2. The cover 4 comprises a base 12 from which extends a skirt 13. The latter 13 is installed in the opening 6 of the support. A clearance is provided between the skirt 13 of the cover and the wall 11 of the support so as to facilitate the mounting of the device 1. The cover 4 comprises a flange 15 which extends the wall of the base 12 and overhangs the skirt 13. The flange 15 has orifices 29 allowing the passage of fasteners for fixing the cover 4 to the support 2.

The measuring device 1 also comprises at least one seal 14 as shown in FIG. 6 and which makes it possible to prevent leakage of the flow, in particular of the secondary flow of the secondary vein 105 through the gap. flow then flowing from the opening and then through the light are avoided. The seal 14 is removably disposed in each lumen 7 and has a shape complementary thereto. According to one characteristic of the invention, this seal is obtained by molding. This one presents here a parallelepipedic form.

In particular, as illustrated in FIG. 7, the seal 14 has an excess thickness e along its height h and with respect to that of the light 7 in which it is received. In other words, the seal has a surface 18 which is defined in a plane BC offset and parallel to the plane AB of the support. The extra thickness e is between 0.5 mm and 3 mm. Preferably, but without limitation, the excess thickness e is of the order of 1 mm. This extra thickness is partially covered by the flange 15 of the lid. The seal further comprises keying means 26 enabling it to be correctly positioned in the slot 7 during assembly. As illustrated in FIG. 8, when the cover closes the opening 6 of the support, the cover (the flange 15) presses on the surface 18 of the seal facing the flange 15 so as to compress or crush the excess thickness and that it embraces the entire surface of the light 7. Thus, the seal is optimal.

The seal 14 is made of a polymeric material. Preferably, but not exclusively, this polymer is a polydimethylsiloxane (PDMS). An example of polydimethylsiloxane to make the seal would be a Rhodorsil® RTV 3255. The latter has a hardness (55 Shore A) comparable to that of silicone, that is to say quite flexible.

This seal 14 is manufactured by means of a mold 16 obtained by stereolithography. The mold 16 here comprises a first portion 17a and a second portion 17b forming a chamber. This allows rapid demolding of molded joints. The first part and the second part are provided with complementary positioning means for removably fixing the first and second parts together.

According to the embodiment illustrated in FIG. 9, the complementary positioning means comprise pins 19 provided on a connecting wall 23 of the first part 17a and openings 20 on the connecting wall 23 of the second part 17b.

According to the embodiment illustrated in FIG. 10, the positioning means comprise grooves 24 and ribs 25. In particular, the groove 24 extends along the connecting wall 23 of the second portion 17b and the rib extends along the connecting wall 23 of the first part 17a. In this embodiment, an inner surface 21 of each first portion 17a and second portion 17b comprises a projection 22 intended to form the keying means of the seal 14. In the example shown, each projection 22 forms an arrow which tells a user / operator proper positioning during editing.

Such a mold allows the fluid polymer to access all parts of the mold, to avoid air bubbles, drips during injection and to ensure clean demolding.

Thus, a polymer, here Rhodorsil® RTV 3255 is poured into the mold chamber. After demolding, the seal is obtained in the profile of the light 7.

When mounting the flow measuring device 1 in the turbomachine, the support is fixed on the outer casing. The measuring means is inserted through the opening 6 of the support, the connecting members 28 slide through the slots 7 and then the measuring means is fixed to the support (see FIGS. 3a to 3c). A seal 14 is placed in each lumen 7 of the support. The cover is installed in the opening and fixed on the support. By simply pressing the lid, and in particular the flange on the extra thickness, and the low hardness of the RTV 3255, the seal expands to fill all the light 7. In a particular embodiment of the invention, the stress of the cover on the joint having a thickness of 1 mm allows a lateral expansion thereof of at least 0.64 mm. This expansion fills the clearance of about 0.2 mm left between the seal and the light and thus completely seal the leak.

Claims (10)

1. Device (1) for measuring parameters of an aerodynamic flow in a turbomachine (100), the device (1) comprising a measuring means (3) capable of measuring said parameters, a support (2) which can be fixed a casing (101) of the turbomachine (100) and carrying said measuring means (3), the support (2) comprising a wall (5) provided with a main through opening (6) and at least one secondary through-hole opening into the main opening, the main opening (6) and the secondary through-hole (7) allowing passage of the measuring means during its assembly, a cover (4) configured to close or release the through opening (6) of the support, and a seal (14) molded and removably arranged in the lumen (7). 2. Device (1) according to revendcation 1, characterized in that the seal is covered at least partially by the cover. 3. Device (1) according to any one of the preceding claims, characterized in that the seal (14) has an excess thickness configured to be crushed by the cover (4). 4. Device (1) according to claim 3, characterized in that the extra thickness is between 0.5 mm and 3 mm. 5. Device (1) according to any one of the preceding claims, characterized in that the seal (14) comprises polarizing means (26). 6. Device (1) according to any one of the preceding claims, characterized in that the seal is made of a polydimethylsiloxane material. 7. turbomachine (100) with a double flow comprising a housing (101) which extends along a longitudinal axis (X) and which defines a vein (105, 106) in which flows, characterized in that it comprises a Device (1) according to any one of claims 1 to 6 which is fixed to said housing (105). 8. A method of manufacturing a seal (14) of a device (1) according to any one of claims 1 to 6, characterized in that it comprises the steps of using a mold (16). ) obtained by stereolithography which comprises a first portion (17a) and a second portion (17b) each provided with complementary positioning means (19, 20; 24, 25) and forming the mold chamber, and the injection of a polymer in the mold chamber. 9. The method of claim 8, characterized in that the positioning means comprise a groove and a rib extending respectively along the connecting walls (23) of the first portion (17a) and the second portion (17b). 10. Method according to any one of the preceding claims, characterized in that the inner surface of each first and second parts (17a, 17b) comprises a projection for forming the keying means.