RU2784992C2 - Device for measuring airflow characteristics - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: invention relates to device (46) for measuring airflow characteristics in an annular channel of a turbomachine, containing rod (44), which passes along first set axis (54), and on which a means for measuring airflow characteristics is retained, wherein the specified rod is installed with the possibility of tight sliding in first tubular part (62), from which second tubular part (64) passes, tightly sliding along first axis (54) through slider (66) installed in a guide rail with the possibility of sliding along second axis (56) perpendicular to first axis (54), wherein rod (44) is connected to second tubular part (64) to form an annular gap.

EFFECT: obtainment of a device for measuring airflow characteristics.

13 cl, 21 dwg

Description

Scope of the invention

[001] The present invention relates to an apparatus for measuring airflow characteristics in a turbomachine, such as a test turbomachine.

State of the art

[002] Typically, the bypass turbofan engine 10, as shown in FIG. 1 comprises a gas turbine 12 with an axis of rotation 14 for driving a shrouded fan wheel 16, said wheel generally located upstream of the turbofan engine. The mass of air drawn in by said engine is divided into a primary airflow (arrow A) which flows through the gas turbine 12 or engine interior, and a secondary airflow (arrow B) generated by fan 16 and surrounding the interior of the engine, both primary and secondary the air flows are concentric and circulate in the primary annular channel 18 and the secondary annular channel 20, respectively 8.

[003] As is known, the primary air stream (arrow A) is generally compressed by a low pressure compressor 22 and then by a high pressure compressor 24, each of which contains both fixed 26 and movable blades arranged in alternating direction. flow movement. The shaft of the low pressure compressor is connected to the fan wheel 4 and is rotatable by means of the shaft of a low pressure turbine located downstream (not shown). The low pressure compressor shaft is configured to be driven by a high pressure turbine shaft located at the outlet of the combustion chamber upstream of the low pressure turbine (both turbines not shown).

[004] In a twin-cassette turbofan engine of this type, the fan shroud is typically the outer annular wall 28 surrounding the wheel 16, and the intermediate shroud 30 is a turbomachine structural element that is located axially between the low pressure compressor 22 and the high pressure compressor 24 and extends through primary 18 and secondary 20 annular channels. This intermediate housing 30 has two annular walls, radially inner 32 and radially outer 34, respectively limiting, from the inside and outside, the annular channel 18 for the primary air flow, and two annular walls, radially inner 36 and radially outer 38, limiting, respectively, from the inside and outside secondary annular channel 20.

[005] When developing a turbofan engine for its certification, it is necessary to test its performance. For this, experimental turbomachines are used. Many measurements are carried out on such turbomachines. The airflow characteristics are in particular measured at different axial positions or measurement planes 40a, 40b, 40c. In addition, it is necessary to be able to carry out measurements at several points on the measuring plane.

[006] For this, measuring elements known as measuring sensors, which are located in the measuring planes, are usually used to determine the characteristics of the aerodynamic flow by measuring parameters such as pressure and temperature, for example, during operation. Such a device 42a, 42b, 42c includes a rod 44 on which the means for measuring the characteristics of the air flow is held. The device also has a radially outer end and a radially inner end relative to the axis of rotation 14 of the turbomachine. The radially outer end of the component 42a, 42b, 42c is held by the turbomachine casing, and the radially inner end, located in the flow path, is free and located in the turbomachine airflow to be measured.

[007] More specifically, the radially outer end is attached to the mounting base of the housing to support the rod 44 in a predetermined constant radial direction. If it is necessary to take measurements at different radial locations, it is necessary to stop the turbomachine, move the base of the rod to a different position, and restart the turbomachine. As practice shows, these stages are lengthy and complicate the testing phases. In addition, at certain fan speeds, especially when the sensing rod 44 passes through an annular secondary airflow, the rod 44 may enter into resonance, which may crack it and may affect its mechanical integrity. In extreme cases, the formation of breaks or cracks due to vibrations can lead to partial or complete displacement of the rod 44. The particles thus separated circulate in said channel and can damage downstream components of the turbomachine.

[008] In known systems, it is proposed, for example, to mount a rod on a radially sliding means of movement and on a means of movement in an angular or circumferential direction. However, this installation option does not provide an optimal tightness of the air flow, so the measurement affects the characteristics of the measured air flow.

[009] It is an object of this invention, in particular, to provide a simple, effective and economical solution to the problems of the prior art described above.

The essence of the invention

[0010] Thus, according to the present invention, there is provided a device for measuring air flow characteristics in an annular flow of a turbomachine, said device comprising a rod that extends along a first predetermined axis and on which an air flow characteristic measuring means is held, said rod being mounted with the possibility of hermetic sliding in the first tubular part, passing into the second tubular part, which is hermetically held along the specified first axis through the slider mounted with the possibility of sliding in the guide along the second axis perpendicular to the specified first axis, and the specified rod is installed in the specified second tubular part with an annular gap.

[0011] In accordance with this invention, the seal is made in two different locations on two different axes of movement of the rod, which simplifies the design of the measuring device. In particular, the seal for the guide is made in said second tubular part, and the seal against the air flowing in said second tubular part is made directly on the rod itself.

[0012] Another feature of the present invention is that the slider is preferably cylindrical and comprises a first telescopic tubular part and a second telescopic tubular part, said first and second telescopic tubular parts being sealed at one axial end to said second tubular part.

[0013] Through the use of telescopic tubular sliders, the pressure of the air entering through the annular gap between the rod and said second tubular part is distributed evenly over the individual tubes forming the first and second slider parts.

[0014] Said first tubular part may comprise a first support plate on which, when rotating about said first axis, the first actuating means is supported to ensure translational movement of the rod along said first axis.

[0015] For cooling said first plate, such plate may comprise a circuit in which air is circulated and which is configured to be connected to the air supply means. Thus, the thermal control of said first plate limits the heating of the parts attached thereto. It should be understood that said first plate is preferably also tubular, i. has at least one central hole for passing said rod.

[0016] In a specific configuration, the first and second tubular parts, located coaxially with the specified first axis, are installed around the rod, and the first tubular part surrounds the second tubular part and together with it defines a circuit in which the cooling liquid is circulated and which is made with the possibility of connection with coolant supply. This design, in combination with the cooling air circuit, provides even more efficient temperature control of said device.

[0017] Preferably, the first tubular part is inserted into a hole in said first plate and is integral with said first plate.

[0018] In order to ensure tight directional movement of the rod and limit the upward movement of hot gases, a guide tube can be placed inside the first tubular part inside the said part, in which the specified rod is installed with a sliding fit with a very small gap.

[0019] The guide tube may include an annular flange sandwiched between an annular protrusion at the first end of said second tubular part and a clamp nut screwed onto the second end of said second part.

[0020] Advantageously, a seal may be fitted around the stem, sandwiched along said first axis between two rings, said two rings and the seal being placed between said guide tube flange and said nut.

[0021] To move said second and first parts along the second axis, said second tubular part is integral with the second plate, which is mounted to move along the second axis by means of a rack and pinion system.

[0022] The base can be fixedly attached to the surface of the guide opposite to that on which the said first tubular part rests, and the specified base has an opening through which the specified rod passes, and contains a circuit in which the cooling liquid is circulated and which is configured to connection with the means of supplying the cooling fluid.

[0023] Preferably, the guide comprises a circuit in which air is circulated and which is connected to a means for supplying cooling air.

[0024] The present invention also relates to an air duct for a turbomachine, which includes two coaxial annular walls, an inner and an outer one, and the device described above, wherein the guide is fixedly attached to the radially outer surface of the outer annular wall, and the rod passes through the specified outer annular wall so that that its free end is located between said two annular walls, inner and outer.

[0025] The present invention will become better understood and other details, characteristics and advantages thereof will become apparent upon reading the following description, which is given by way of non-limiting example with reference to the accompanying drawings.

Brief description of the drawings

Fig. 1 described above is a schematic half axial section of an aircraft turbofan engine of known type;

Fig. 2 is a schematic axonometric view of an apparatus according to the invention for making measurements of airflow characteristics in an annular airflow passage;

Fig. 3 is a schematic sectional view of a device according to the invention;

FIG. 4 is an enlarged view of the area delimited by the dotted lines in FIG. 4A;

Fig. 3 is a schematic perspective view of part of the apparatus according to the invention, exploded;

Fig. 6 schematically shows a perspective view of a rod and a sealing means by which the rod is slid in the radial direction;

Fig. 7 schematically illustrates the deformation of the seal when the rod slides;

Fig. 8A, 8B and 8C schematically show means for moving the measuring rod in the tangential direction;

Fig. 9A, 9B and 9C are schematic longitudinal sections of a guide and a cylindrical slider movable in a tangential direction;

Fig. 10A, 10B, 11A and 11B are schematic sectional views in a plane perpendicular to the radial direction, showing the inside of the guide;

Fig. 12A, 12B, and 12C are schematic perspective views and in different cutting planes in the radial direction of a liquid cooling means;

Fig. 13 schematically shows in a perspective view the means for cooling the support plate by means of air circulation during the radial movement of the measuring rod.

Detailed description

[0026] In FIG. 2 shows a device 46 according to the invention held on an outer casing 48 of a turbomachine and comprising three actuators 50, 52, 54, the first actuator 52 moving the measuring rod 44 along a first axis 56 extending in the radial direction, the second actuator 54 providing rotational movement of the rod 44 around said first axis 56, and the third actuator 54 moves the rod 44 along the second axis 58 perpendicular to the first axis 56. The second axis 58 extends in a direction perpendicular to the radial direction, which corresponds to the first axis 56, and perpendicular to the longitudinal direction 60 parallel to the rotational axis 14 of the turbomachine, with the airflow flowing in one direction along said longitudinal direction.

[0027] FIG. 3 shows the device 46. In FIG. 3 shows a section in the plane in which the first axis 56 and the second axis 58 extend. The device 46 includes a first tubular part 62, which extends along the first axis 56 and from which a second tubular part 64 departs, sealingly crossing a cylindrical slider 66 mounted with the possibility of sliding in the guide 68, and the slider 66 is movable along the second axis 58.

[0028] More specifically, the first tubular portion 62 includes a tubular body 70 formed at its radially inner end and integral with the first plate 72 that supports the measuring rod 44 when moving along the first axis 56 and when rotating about the first axis 56 (Fig. 4). The first plate 72 has an opening centered on the first axis 56 in which the first tubular portion 74a and the second tubular portion 74b are aligned with the first axis 56, with the first tubular portion 74a surrounding the second tubular portion 74b. As seen in FIG. 4, at the radially inward end of the first tubular portion 74a, there is an annular flange 76 sandwiched between the tubular body 62 and the first plate 72. In addition, the first tubular portion 74a has a radially inner annular projection 78 on which the radially inner end or the first end of the second tubular portion 74b is mounted with a radially inward stop. Similarly, this first end of the second tubular portion 74b has an annular shoulder 80 on which a radial annular flange 82 of the guide tube 84 is mounted with a radially internal stop, with which the rod 44 is slidingly fitted along the first axis 56 and in which the rod 44 is installed. better seen in Fig. 6, the guide tube 84 is made up of two parts 84a, 84b for mounting the guide tube 84 around the rod 44, since the rod has an airflow characteristic measuring means provided on its radially inner part intended to be installed inside the pipe. Each part 84a, 84b of the tube 84 contains a semi-cylindrical part 85a, 85b, one end of which is connected to a radial semi-annular flange 82a, 82b. The flanges 82a, 82b together form an annular flange 82, and the semi-cylindrical parts 85a, 85b form a cylindrical part 87. At the second end or radially outer end of the second tubular part 74b, a nut 86 is placed, with which a connector 88 is tightened located between the two rings 90a, 90b . Two rings 90a, 90b, a seal 88 and a nut 86 are placed coaxially with the first shaft 56 and are mounted around the stem 44. The stem 44 has a very close slip fit, i.e. without a gap in the guide tube 84, which allows it to slide freely, but prevents hot air from entering from the annular air stream.

[0029] As shown in FIG. 7, seal 88 is substantially flat at rest and has two substantially flat opposite surfaces. Each of the two rings 90a, 90b has one surface 92a, 92b inclined with respect to the first axis 56, said two surfaces 92a, 92b being similarly inclined, i.e. so that the angle between them is close to zero. Owing to this configuration of the rings 90a, 90b, an optimum compression of the seal 88 is ensured, which consequently improves the tightness of the fit.

[0030] The first plate 72 is supported by a carrier plate 94 rotatably mounted on the first axis 56. This carrier plate 94 provides support for the first actuator 50, which holds the rod 44 and which ensures its translational movement in the first tubular part 62. The second actuator 52 rests on the first plate 72, allowing the base 94 to rotate about the first axis 56. Thus, it is possible to optimally adjust the position of the measuring equipment of the measuring rod 44 in the direction of the air flow in the annular air flow.

[0031] The second tubular part 64 includes a tube 96 mounted with a radially outer stop in the tubular part 98 of the second plate 100, which is movable along the second axis 58. parts 64 along the second axis 58 (Fig. 8 and 9) through the rack and pinion system 102. In this example, rack and pinion system 102 rests on guide 68.

[0032] The cylindrical slider 66 is mounted in a guide 68, which is also cylindrical in shape, and includes a first part 104a and a second part 104b with telescopic cylindrical tubes, i. the composite tubes 106a, 106b are slidably inserted into each other. Each part 104a, 104b contains three tubes 106a, 106b inserted into each other. The two parts 104a, 104b of the telescopic tubular slider are attached at one end to a tube 96 which is coaxial with the first axle 56 to provide an airtight seal to the annular passage. As seen in FIG. 3, tube 96 is sized such that stem 44 is surrounded by tube 44 with a gap. The use of sliders with telescopic tubes has the advantage that a better pressure distribution of the annular airflow is provided, while its influence on the sliding movement of the individual tubes 106a, 106b of each slider part 104a, 104b relative to each other is significantly reduced. In one embodiment, the tubes 106a, 106b are machined with a gap of 8 to 15 microns to allow sliding and prevent leakage during operation.

[0033] To limit the increase in operating temperature of the device 46, a first cooling circuit using air (FIGS. 10A and 10B) and a first cooling circuit using a liquid such as water (FIGS. 11A and 11B) are provided. Thus, the guide 68 comprises, in its middle portion, a first air cooling circuit 108 with four channels 108a, 108b, 108c that extend along the second axis 58. In fact, the air circuit comprises two hydraulically independent subcircuits. The first subloop contains channels 108a and 108c, and the second subloop contains channels 108b and 108d. The channels 108a and 108b are connected at one end to the compressed air supply means 109 and are connected, respectively, to the channels 108c and 108d, which communicate with the external environment through holes 110 made in the guide 68 (FIGS. 10A and 10B). Thus, the guide 68 can be cooled during operation.

[0034] The device 46 of the present invention is integrally supported by a base 112 for attachment to a housing, its bolted members 114 being shown in FIG. 11A and 11B. This base 112 has a central hole 116 for the passage of the tool rod 44. The first water cooling circuit 118 contains four channels 118a, 118b, 118c, 118d, which are made in the thickness of the base 112 and extend along the second axis 56. The first channel 118a and the second channel 118b are made in the same first plane perpendicular to the first axis 54 The third channel 118c and the fourth channel 118d are formed in the same second plane perpendicular to the first axis 54. Said first plane extends radially outward relative to said second plane. The first channel 118a is connected to the means 120 for supplying cooling water to the base 112, after which water flows into the third channel 118c, then into the fourth channel 118d, and finally into the second channel 118b and exits from one end thereof. Thus, cooling of the base 112 during operation is ensured, which facilitates the testing phases of the turbomachine.

[0035] As seen in FIG. 10A, 10B, 11A and 11B, the first air cooling circuit 108 is used without the first water cooling circuit 118. To do this, it is sufficient not to insert the base 112 between the housing 48 and the first circuit 108. It is obvious that the addition of the first water cooling circuit 118 makes it possible to further limit the heating of the device 48 according to this invention, in particular due to the greater thermal conductivity of water compared to air.

[0036] Device 46 also includes a second air-cooled circuit 122 and a second liquid-cooled circuit 124, such as water. The second water cooling circuit 124 is provided at the first 74a and second 74b tubular portions, as seen in FIG. 12A, 12B and 12C. The first tubular portion 74a comprises a coolant inlet side member 126 connected to the coolant supply means 128 and a liquid outlet side member 130 . An inlet 126 is positioned below the outlet 128 to allow liquid to flow upwards. As seen in FIG. 12C, the second tubular portion 74b has a lower annular recess 132a and an upper annular recess 132b, which are connected to each other by axial grooves 132c. These recesses 132a, 132b and grooves 132c, together with the inner surface of the first tubular portion 74a, define a circuit in which the cooling medium is circulated. Thus, coolant flows from inlet member 126 into lower annular recess 132a, then along grooves 132c, into upper annular groove 132b, and out through upper member 130.

[0037] In FIG. 13 shows the first section 72 in a sectional plane perpendicular to the first axis 54. As seen in the drawing, the first plate 72 has a first air inlet 134 and a second air inlet 136 that extend from opposite edges of the first plate 72, and each of of them is connected to the air supply means 137. The first air inlet element 134 communicates through a connecting channel 138 with an annular groove 142 which fluidly connects holes 140 made in the thickness of the wall of the first tubular portion 74a and opens along the first axis 54 and upwards into the annular space between the element 94 and the rod 44. The second the air inlet 136 communicates with axial passages 144a, 144b, 144c, 144d, which are connected to each other and together form a square shape. Drilled holes 146 are made in the thickness of the first plate 72 and open in the first direction from the first axis 54 on the underside of the first plate 72 and in the second direction into the channels 144a, 144b, 144c, 144d. Thus, the air entering through the second element 136 flows through the channels 144a, 144b, 144c, 144d, cools the first plate 72 and exits through the holes 146.

[0038] In a specific embodiment of the apparatus described above, it may comprise only one or at least one of the first air-cooled circuit 108, the first liquid-cooled circuit 118, the second air-cooled circuit 122, the second liquid-cooled circuit, and the second liquid-cooled circuit 124.

Claims (13)

1. A device (46) for measuring the characteristics of the air flow in the annular flow of a turbomachine, containing a rod (44) that runs along the first given axis (56) and on which the means for measuring the characteristics of the air flow is held, and the specified rod is installed with the possibility of tight sliding in the first tubular part (62), passing into the second tubular part (64), which is sealed along the specified first axis (56) through the slider (66), which is slidably installed in the guide along the second axis (58) perpendicular to the specified first axis (56), and the specified rod (44) is installed in the specified second tubular part (64) with an annular gap. 2. The device according to claim. 1, in which the slider (66) is preferably cylindrical and contains a first telescopic tubular part (104a) and a second telescopic tubular part (104b), and said first (104a) and second (104b) telescopic tubular parts are sealed attached with one axial end to said second tubular part (64). 3. The device according to claim 1 or 2, in which the specified first tubular part (62) contains the first support plate (72), on which, when rotating around the specified first axis (54), the first actuator (50) rests to ensure the translational movement of the rod (44) along said first axis (54). 4. Device according to claim. 3, in which the specified first plate (72) contains a circuit (122), made with the possibility of air circulation and intended for connection with the means (137) air supply. 5. The device according to claim 3 or 4, in which the first tubular part (74a) and the second tubular part (74b) are installed coaxially with the specified first axis (54) around the rod (44), and the specified first tubular part (74a) surrounds the specified the second tubular part (74b) and together with it defines the circuit (124), made with the possibility of circulation of the coolant and intended for connection with the means (128) for supplying coolant. 6. The device according to paragraphs. 4 and 5, in which said first tubular part (74a) is inserted into a hole in said first plate (72) and is integral with said first plate (72). 7. The device according to one of paragraphs. 1-6, in which a guide tube (84) is placed inside said first tubular part (62), in which the rod (44) is slidably mounted to ensure an accurate fit. 8. The device according to claim 7 in combination with claim 5, wherein the guide tube (84) comprises an annular flange (82) sandwiched between an annular shoulder (80) at the first end of said second tubular part (74a) and a clamp nut (86 ) screwed onto the second end of said second tubular portion (74b). 9. The device according to claim 8, in which a seal (88) is installed around the rod (44), compressed along the specified first axis (54) between two rings (90a, 90b), said two rings (90a, 90b) and the seal ( 88) are placed between said annular flange (82) of the guide tube (84) and the nut (86). 10. The device according to one of paragraphs. 1-9, in which said second tubular part (64) is integral with a second plate (100) movable along said second axis (56) by means of a rack and pinion system. 11. The device according to one of paragraphs. 1-10, containing a base (112) fixedly attached to the surface of the guide (68), opposite the surface on which the said first tubular part (62) rests, and the said base (112) has a hole through which the rod (44) passes, and a circuit (118) configured to circulate the coolant and designed to be connected to the coolant supply means (120). 12. The device according to one of paragraphs. 1-11, in which the first guide (68) contains a circuit (108) made with the possibility of air circulation and intended for connection with the means (109) for supplying cooling air. 13. Duct for a turbomachine containing two coaxial annular walls, inner and outer, and the device (46) according to one of paragraphs. 1-12, moreover, the guide (68) is fixedly attached to the radially outer surface of the outer annular wall (48), and the rod (44) passes through the specified outer annular wall (48) so that its free end is located between the said two annular walls, the inner and external.

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