Process structure with non-axisymmetric housing having controlled opening

Abstract

The present invention relates to a kind of casing (200) of turbo engine compressor, including opening (201), the opening (201) is made from the inner surface (2001) of casing on the thickness of casing, and it is arranged adjacent to each other on the circumference of the casing, it is characterized in that, the casing further includes the movable ring (220) formed by at least two annular parts, the movable ring exists on the outer surface (2002) of opposite opening of casing, and can be moved along the circumference of casing, to open and close the opening of casing, to enable or disable the casing processing structure, movable ring includes the same number of slot (202) with the opening existing in casing.

Description

TECHNICAL FIELD

[0001] The present invention relates to the general field of compressors in gas turbine engines, and more particularly to a treatment structure of a compressor casing of a gas turbine engine. BACKGROUND

[0002] The compressor of a gas turbine engine is composed of blades rotatingly arranged inside a casing which seals the airflow coming from the outside of the engine.

[0003] It is known that the gap existing between the tip of the movable compressor blades and the casing forming the inner wall of the airflow deteriorates the efficiency of the gas turbine engine.

[0004] Moreover, this gap can change and deteriorate the operation of the compressor until the phenomenon called compressor stall begins due to the disruption of the airflow on the blade surface. The control of the air circulation at the tip of the blades becomes a major challenge to obtain both a good aerodynamic efficiency of the compressor and a sufficient margin against the compressor stall phenomenon.

[0005] To limit the effects of this parasitic flow between the tip of the blades and the casing, the inner surface of the casing can be locally treated by cutting in the thickness of the casing, opposite the blades, a recess arranged in the inner surface of the casing. The documents FR 2989 742, GB 2 408 546 and US 2016 / 153465 provide embodiments of casing structures.

[0006] However, the phenomenon of compressor stall only occurs when the compressor is at high load, i.e. when it is operating at the top of its operating range. Thus, outside this region, the casing treatment structure is no longer useful, even causing a loss of compressor efficiency.

[0007] It would therefore be desirable to provide a compressor casing in which the slots of the casing treatment structure can be opened or closed to prevent the stall phenomenon while maintaining good compressor efficiency. SUMMARY

[0008] The present invention relates to a casing of a compressor of a gas turbine engine comprising openings cut in the thickness of the casing from the inner surface of the casing and arranged side by side on the circumference of the casing, characterized in that it further comprises a movable ring formed of at least two annular parts positioned on the outer surface of the casing opposite the openings and movable along the circumference of the casing in order to close or open the openings of the casing to activate or deactivate the casing treatment structure; the movable ring comprises the same number of slots as the openings present in the casing.

[0009] When the openings in the casing are aligned with the slots of the movable ring, i.e. when the casing openings are located opposite the slots of the movable ring, the openings on the casing form the slots of the non-axially symmetrical casing treatment structure, since they exist along the circumference of the casing and are open to the airflow. In other words, they form axial slots arranged in the azimuthal direction, and are therefore non-axially symmetrical with respect to the rotation axis of the compressor, whereas an axially symmetrical casing treatment structure would consist of circumferential slots and would be symmetrical with respect to the rotation axis of the compressor.

[0010] With the invention, it is possible to open or close the slots of the casing treatment structure by means of the movable ring. This makes it possible to obtain an active casing treatment structure when such operating conditions are required, for example at take-off, to prevent the stall phenomenon, and to obtain an inactive casing treatment structure when the compressor is no longer under load, for example at cruising speed, to prioritize compressor efficiency. The invention thus provides control of the openings of the casing treatment structure.

[0011] According to one particular feature of the invention, each opening of the casing has a width greater than or equal to the width of the associated slot of the movable ring, and each opening of the casing has a length greater than or equal to the length of the associated slot of the movable ring.

[0012] According to another particular feature of the invention, the casing further comprises at least one spring that assembles the movable ring to the casing and is configured so that the openings of the casing are open when the spring is not under stress.

[0013] The spring allows the movable ring to return to an initial or safe position in which the ring slots are located opposite the openings of the casing, so that the slots of the casing treatment structure are completely open to obtain an active casing treatment structure.

[0014] According to another particular feature of the invention, the casing comprises an electric motor comprising a camshaft, the cam being configured to move the movable ring along the circumference of the casing to open or close the casing openings.

[0015] The camshaft allows the movable ring to be moved along the circumference of the casing, and more particularly the cam allows the movable ring to be moved by an amplitude at least equal to the width of the openings of the casing to obtain complete opening or closing of the casing openings, and therefore complete opening or closing of the slots of the casing treatment structure.

[0016] According to another particular feature of the invention, the casing comprises an actuator configured to move the movable ring along the circumference of the casing to open or close the casing openings.

[0017] The actuator can act in the same way as the camshaft, thus allowing the movable ring to move along the circumference of the casing to close or open the slots of the casing treatment structure. Thus, it allows the movable ring to move an amplitude at least equal to the width of the casing opening.

[0018] According to another particular feature of the present application, the slot of the movable ring and the casing opening are of the same size.

[0019] This means that the slot of the movable ring and the casing opening have the same length and the same width. This facilitates the opening and closing of the slots of the casing treatment structure, since by moving the movable ring over the width of the casing opening, it is possible to obtain the full opening or closing of the corresponding slots of the casing treatment structure.

[0020] According to another particular feature of the present application, the number of openings in the casing is between 40 and 850.

[0021] According to another particular feature of the present application, the movable ring and the casing are made of the same material. BRIEF DESCRIPTION OF DRAWINGS

[0022] Other characteristics and advantages of the present application will become apparent from the description given below, with reference to the attached drawings which illustrate, by way of non-limiting example, embodiments of the application.

[0023] Figure 1 is a partial view of a casing of a compressor of a gas turbine engine according to an embodiment of the present application.

[0024] Figure 2A is a partial view of a closed slot of a compressor casing treatment structure in Figure 1

[0025] Figure 2B is a partial view of an open slot of a compressor casing treatment structure in Figure 1

[0026] Figure 3 is a partial view of a casing of a compressor of a gas turbine engine according to another embodiment of the present application. DETAILED DESCRIPTION

[0027] Figure 1 A casing 100 of a compressor of a gas turbine engine according to a first embodiment of the present application is shown partially and schematically.

[0028] The casing 100 comprises openings hollowed out (or cut out) in the thickness of the casing from the inner surface 1001 of the casing 100. The openings are arranged side by side on the circumference of the casing 100.

[0029] ​​The housing 100 further comprises a movable ring 120 on the outer surface 1002 of the housing 100. The movable ring 120 comprises as many slots as there are openings in the housing 100 and is movable along the circumference of the housing 100 to open or close the openings of the housing 100 via the ring slots. By alignment of the slots of the movable ring 120 with the openings of the housing 100, i.e. when the slots of the movable ring 120 are located opposite the openings of the housing 100, a housing processing structure is formed having slots that are open when the openings of the housing 100 are open. In other words, the movable ring 120 is rotated around the housing 100 to close or open the openings of the housing 100.

[0030] Each opening of the housing 100 has a width that is greater than or equal to the width of the associated slot (or slot facing said opening) of the movable ring 120 and each opening of the housing 100 has a length that is greater than or equal to the length of the associated slot (or slot facing said opening) of the movable ring 120. This guarantees that the openings of the housing 100 are completely open when the housing processing structure needs to be enabled.

[0031] Furthermore, the distance between each opening of the housing 100 is greater than or equal to the width of the associated slot of the movable ring 120. This guarantees that the openings of the housing 100 are completely closed when the housing processing structure is desired to be disabled.

[0032] The movable ring 120 is formed by two ring portions 121, 122. In this first embodiment, the two ring portions 121 and 122 are assembled together via self-drilling screws 130, but they can alternatively be assembled by any other assembly means, for example, by a system consisting of a guiding pin and a screw and nut assembly for holding in place.

[0033] By having a movable ring 120 formed by at least two ring portions 121 and 122, this facilitates the mounting of the movable ring 120 on the housing 100.

[0034] The housing 100 comprises a piston 140 fixed at one end thereof to the movable ring 120 and at the other end thereof to the housing 100 via a pull rod 125. The piston 140 provides control of the movement of the movable ring 120 along the circumference of the housing 100 for a movement of the movable ring equal to at least the width of the openings of the housing 100 to completely close and / or completely open the openings of the housing 100, thus opening the slots of the housing processing structure. The pull rod 125 allows the rigidity of the housing 100 and provides a fixing point for the piston 140.

[0035] In order to move the movable ring 120 on the housing 100, the piston 140 can be replaced by an actuator.

[0036] Figure 2A and 2B shows Figure 1 the cross-section of the opening 201 of the casing 200 when it is open ( Figure 2B ) or closed ( Figure 2A ), obtained by the movement of the movable ring 200 and by its slots 202. As shown in Figure 1 , the openings 201 of the casing 200 are hollowed out or cut out in the thickness of the casing 200 from its inner surface 2001 and are arranged side by side on the circumference of the casing 200. The movable ring 220 comprises the same number of slots 202 as the openings 201 present in the casing 200 and it is positioned on the outer surface 2002 of the casing 200 so that it can close or open the openings 201 of the casing 200 by moving around the circumference of the casing 200. In the example of this embodiment, the slots 202 of the movable ring 220 have the same width and length as the openings 201 of the casing 200. Furthermore, the distance between the openings 201 of the casing 200 is the same as the distance between the slots 202 of the movable ring 220. Therefore, when the slots 202 of the movable ring 220 coincide with the openings 201 of the casing 200, the openings 201 of the casing 200 are completely open ( Figure 2B ) and the slots of the casing handling structure are open. When the slots 202 of the movable ring 220 cover the openings 201 of the casing 200, the openings 201 of the casing 200 are completely closed and the slots of the casing handling structure are closed ( Figure 2A ). Therefore, in the case shown in Figure 2A , the casing handling structure 200 is deactivated (the slots of the casing handling structure are closed) and, in the case shown in Figure 2B , it is activated (the slots of the casing handling structure are open).

[0037] Figure 3 The casing 300 of a gas turbine engine compressor 310 according to a second embodiment of the present application is shown partially and schematically.

[0038] As shown in Figure 1 , the casing 300 comprises openings hollowed out or cut out in the thickness of the casing 300 from its inner surface 3001. The openings are arranged side by side along the circumference of the casing 300.

[0039] The casing 300 also comprises a movable ring 320 on the outer surface 3002 of the casing 300. The movable ring 320 comprises the same number of slots as the openings present in the casing 300 and it can move around the circumference of the casing 300 to open or close the slots of the casing structure using its own slots to open or close the openings of the casing 300. As shown in Figure 1As shown, each opening of the housing 300 has a width greater than or equal to the width of the associated slot of the movable ring 320, and each opening of the housing 300 has a length greater than or equal to the length of the associated slot of the movable ring 320. Moreover, the distance between each opening of the housing 300 is greater than or equal to the width of the associated slot of the movable ring 320.

[0040] The movable ring 320 is formed of two ring portions 321 and 322. As previously mentioned, the two ring portions 321 and 322 can be assembled together via self-drilling screws or any other assembly means.

[0041] In order to move the movable ring 320, and to close or open the slots of the housing treatment structure, and thus the openings of the housing 300, the housing 300 comprises an electric motor 330 comprising a camshaft 332. By pivoting, the cam 332 allows the movable ring 320 to be moved along the circumference of the housing 300. The cam 332 can be supported on a protrusion 326 on one of the ring portions 322 so that it can pivot and move the movable ring 320. The electric motor 330 and the camshaft 332 allow the movable ring 320 to be moved by an amplitude at least equal to the width of the openings of the housing 300. A tie rod 327 can be used to block the protrusion 326 when the movable ring 320 is in movement.

[0042] The housing 300 can also comprise a spring 340 fixed to the movable ring 320 and to the housing 300 via a tie rod 325. This spring 340 is configured so that when it is not stressed, the openings of the housing 300 are open, i.e. so that the slots of the movable ring 320 do not close the openings of the housing 300 (case in Figure 2B As previously mentioned, in addition to forming a fixed point for fixing the spring 340, the tie rod 325 also allows the rigidity of the housing 300.

[0043] Irrespective of the embodiment, the openings of the housing can all be identical.

[0044] Irrespective of the embodiment, the slots of the movable ring can all be identical.

[0045] Advantageously, the slots of the movable ring and the openings of the housing have identical dimensions, i.e. they have the same length and the same width; and the distance between the openings of the housing is equal to the distance between the associated slots of the movable ring. It is thus possible to obtain a slot of the movable ring which coincides with an opening of the housing, and to move the movable ring only by an amplitude of its slot so that it can completely open or completely close the openings of the housing, and thus also the slots of the housing treatment structure.

[0046] Irrespective of the embodiment, the housing can have a monolithic structure.

[0047] Irrespective of the embodiment, the number of openings in the housing (and thus the number of movable rings) is between 40 and 850, for example between 45 and 810, for example between 60 and 210. The housing handling structure requires between 3 and 8 slots per rotor blade, and the rotor comprises between 15 and 90 blades. With this value range, thus all possibilities can be covered.

[0048] Irrespective of the embodiment, the housing and the movable rings can be made of the same material. This enables both components to withstand the same thermal and mechanical stresses, thereby ensuring that opening or closing of the housing handling structure will always be possible even in case of thermal expansion.

[0049] Alternatively, the housing and the movable rings can be made of different materials, but both materials must have close, even identical physical properties, so that they have similar thermal expansions.

[0050] The expression "between... and..." is to be interpreted as including these extreme values.

Claims

1. A compressor casing of a gas turbine engine comprising openings cut in the thickness of the casing from the inner surface of the casing, said openings being arranged side by side on the circumference of the casing, characterized in that, The housing further comprises a movable ring formed of at least two annular portions, positioned on the outer surface of the housing opposite the openings and movable along the circumference of the housing in order to open or close the openings of the housing to enable or disable the housing processing structure, the movable ring comprising the same number of slots as the openings present in the housing.

2. The compressor casing of claim 1, wherein, Each opening of the housing has a width greater than or equal to the width of the associated slot of the movable ring and each opening of the housing has a length greater than or equal to the length of the associated slot of the movable ring.

3. The compressor housing according to claim 1 or 2, further comprising at least one spring (340) assembling the movable ring to the housing, the spring being configured such that when the spring is not stressed, the openings of the housing are open.

4. The compressor housing according to any one of claims 1 to 3, comprising an electric motor (330) comprising a camshaft (332) configured to move the movable ring along the circumference of the housing such that the movable ring opens or closes the openings of the housing.

5. The compressor housing according to any one of claims 1 to 3, comprising an actuator configured to move the movable ring along the circumference of the housing in order to open or close the openings of the housing.

6. The compressor casing of any one of claims 1 to 5, wherein, The slots of the movable ring are of the same size as the openings of the housing.

7. The compressor casing of any one of claims 1 to 6, wherein, The number of openings in the housing is between 40 and 850.

8. The compressor casing of any one of claims 1 to 7, wherein, The movable ring and the housing are made of one and the same material. The movable ring and the housing are made of one and the same material.

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