Processing structure of non-axisymmetric housing with controlled opening

Abstract

The invention relates to a casing (200) of a compressor of a turbine engine, comprising openings (201) made from an inner surface (2001) of the casing over the thickness of the casing and arranged adjacent to each other over the circumference of the casing, characterized in that the casing further comprises a movable ring (220) formed by at least two annular portions, and a movable ring (202) present on an outer surface (2002) of the housing opposite the opening and movable along the circumference of the housing in order to open and close the opening of the housing to activate or deactivate the housing treatment structure, the movable ring comprising the same number of slots (202) as the openings present in the housing.

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 Art

[0002] The compressor of a gas turbine engine consists of blades rotatably disposed within a casing that seals off the air flow from the external surroundings of the engine.

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

[0004] Furthermore, this clearance can alter and degrade the operation of the compressor until the phenomenon called compressor stall sets in, due to the disruption of the airflow over the blade surface. Control of the air circulation at the blade tip becomes a major challenge both to obtain good aerodynamic efficiency of the compressor and sufficient margin against the compressor stall phenomenon.

[0005] In order to limit the influence of such parasitic flows between the tips of the blades and the casing, the inner surface of the casing can be locally treated by cutting recesses arranged in the inner surface of the casing in the thickness of the casing opposite the blades. Documents FR 2 989 742, GB 2 408 546 and US 2016 / 153465 provide examples of casing structures.

[0006] However, the phenomenon of compressor stall only occurs when the compressor is at high load, that is, when it is operating at the top of its operating range. Therefore, outside this area, the casing treatment structure is no longer useful and even causes a loss of compressor efficiency.

[0007] Therefore, it is desirable to provide a compressor casing in which the slots of the casing treatment structure can be opened or closed to prevent stalling while maintaining good compressor efficiency. Summary of the invention

[0008] The present invention relates to a casing of a gas turbine engine compressor, comprising openings cut from the inner surface of the casing in the thickness of the casing and arranged side by side on the circumference of the casing, characterized in that it also includes a movable ring formed by at least two annular parts, positioned on the outer surface of the casing opposite to the openings and capable of moving along the circumference of the casing so as to close or open the openings of the casing to activate or deactivate the casing processing structure; the movable ring includes 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 in the casing form slots of a non-axisymmetric casing handling structure, since they are present along the circumference of the casing and are directed to the airflow. In other words, they form axial slots arranged in the azimuthal direction and are therefore non-axisymmetric with respect to the axis of rotation of the compressor, whereas an axisymmetric casing handling structure consists of circumferential grooves and is symmetrical with respect to the axis of rotation of the compressor.

[0010] By means of the invention, it is possible to open or close the slot of the case treatment structure by means of a movable ring. This makes it possible to obtain an activated case treatment structure when such operating conditions require, such as take-off, to prevent stall phenomena, and to obtain a deactivated case treatment structure when the compressor is no longer under load, such as at cruising speed, to prioritize compressor efficiency. The invention thus provides for the control of the opening of the case treatment structure.

[0011] According to a particular feature of the invention, 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.

[0012] According to another particular feature of the invention, the housing also comprises at least one spring assembling the movable ring to the housing and configured so that the opening of the housing is open when the spring is not stressed.

[0013] The spring allows the movable ring to return to an initial or safe position, wherein the ring slot is located relative to the opening of the housing, so that the slot of the housing handling structure is fully opened to obtain an activated housing handling structure.

[0014] According to another particular feature of the invention, the housing comprises an electric motor comprising a cam shaft, the cam being configured to move the movable ring along the circumference of the housing so as to open or close the housing opening.

[0015] The cam shaft allows the movable ring to move along the circumference of the housing, and more specifically the cam allows the movable ring to move by an amplitude at least equal to the width of the opening of the housing to obtain full opening or closing of the housing opening and therefore the slot of the housing handling structure.

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

[0017] The actuator can play the same role as a camshaft, thus allowing the movable ring to move along the circumference of the housing to close or open the slot of the housing processing structure. Therefore, it allows the movable ring to move at least equal to the width of the housing opening.

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

[0019] This means that the slot of the movable ring and the housing opening have the same length and the same width. This facilitates the opening and closing of the slot of the housing handling structure, because by moving the movable ring over the width of the housing opening it is possible to obtain a complete opening or closing of the corresponding slot of the housing handling structure.

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

[0021] According to another particular feature of the invention, the movable ring and the housing are made of one and the same material. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other characteristics and advantages of the invention will become apparent from the description given below, with reference to the accompanying drawings, which show examples of implementation which are not limiting in any way.

[0023] Figure 1 FIG. 1 is a partial schematic diagram of a casing of a compressor of a gas turbine engine according to an embodiment of the present invention.

[0024] Figure 2A yes Figure 1 Partial schematic diagram of a closed slot in a compressor casing handling structure.

[0025] Figure 2B yes Figure 1 Partial schematic diagram of an open slot of a compressor casing processing structure in FIG.

[0026] Figure 3 FIG. 1 is a partial schematic diagram of a casing of a compressor of a gas turbine engine according to another embodiment of the present invention. DETAILED DESCRIPTION

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

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

[0029] The housing 100 further includes a movable ring 120 on an outer surface 1002 of the housing 100. The movable ring 120 includes as many slots as the openings present 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 the 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 to the openings of the housing 100, a housing handling structure is formed, which has slots that are opened when the openings of the housing 100 are opened. In other words, the movable ring 120 rotates around the housing 100 to close or open the openings of the housing 100.

[0030] Each opening of the housing 100 has a width greater than or equal to the width of the associated slot of the movable ring 120 (or the slot facing the opening), and each opening of the housing 100 has a length greater than or equal to the length of the associated slot of the movable ring 120 (or the slot facing the opening). This ensures that the opening of the housing 100 is fully opened when it is necessary to activate the housing processing structure.

[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 ensures that the openings of the housing 100 are completely closed when it is desired to deactivate the housing handling structure.

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

[0033] By having the movable ring 120 formed of at least two annular portions 121 and 122 , this facilitates mounting 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 to the housing 100 via a tie rod 125. The piston 140 provides control of the movement of the movable ring 120 along the circumference of the housing 100, for the movable ring to move an amplitude at least equal to the width of the opening of the housing 100, to completely close and / or completely open the opening of the housing 100, thus opening the slot of the housing handling structure. The tie rod 125 allows rigidity of the housing 100 and provides a fixing point for fixing the piston 140.

[0035] To move the movable ring 120 on the housing 100 , the piston 140 may be replaced by an actuator.

[0036] Figure 2A and 2B Show Figure 1 The housing 200 in the opening ( Figure 2B ) or turn off ( Figure 2A ) is a cross-sectional view of the opening 201 obtained by the movement of the movable ring 200 and through its slot 202. Figure 1 As shown, the openings 201 of the housing 200 are hollowed out or (cut out) in the thickness of the housing 200 from its inner surface 2001, and the openings are arranged side by side on the circumference of the housing 200. The movable ring 220 includes the same number of slots 202 as the openings 201 present in the housing 200, and it is positioned on the outer surface 2002 of the housing 200 so that it can close or open the openings 201 of the housing 200 by moving around the circumference of the housing 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 housing 200. In addition, the distance between the openings 201 of the housing 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 housing 200, the openings 201 of the housing 200 are completely opened ( Figure 2B ), and the slot of the shell processing structure is opened. When the slot 202 of the movable ring 220 covers the opening 201 of the shell 200, the opening 201 of the shell 200 is completely closed, and the slot of the shell processing structure is closed ( Figure 2A ). Therefore, in Figure 2A In the case shown in FIG. , the housing handling structure 200 is deactivated (the slots of the housing handling structure are closed), and Figure 2B In the case shown, it is enabled (the slot of the housing handling structure is open).

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

[0038] See Figure 1 As shown, the housing 300 includes openings that are hollowed out or cut out from an inner surface 3001 of the housing 300 in the thickness of the housing 300. The openings are arranged side by side along the circumference of the housing 300.

[0039] The housing 300 also includes a movable ring 320 on the outer surface 3002 of the housing 300. The movable ring 320 includes the same number of slots as the openings present in the housing 300, and it can move around the circumference of the housing 300 to open or close the slots of the housing structure using its own slots to open or close the openings of the housing 300. As shown in FIG. 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. In addition, 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 annular parts 321 and 322. As mentioned before, the two annular parts 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 close or open the slot of the housing processing structure, and thus close or open the opening of the housing 300, the housing 300 includes a motor 330, which includes a cam shaft 332. By pivoting, the cam 332 allows the movable ring 320 to move along the circumference of the housing 300. The cam 332 can be supported on a protrusion 326 on one of the annular parts 322, so that it can pivot and move the movable ring 320. The motor 330 and the cam shaft 332 allow the movable ring 320 to move by an amplitude at least equal to the opening width of the housing 300. The pull rod 327 can be used to block the protrusion 326 when the movable ring 320 is in motion.

[0042] The housing 300 may further include a spring 340 fixed to the movable ring 320 and the housing 300 via the tie rod 325. The spring 340 is configured so that when it is not stressed, the opening of the housing 300 is open, that is, so that the slot of the movable ring 320 does not close the opening of the housing 300 ( Figure 2B As mentioned above, in addition to forming a fixing point for fixing the spring 340, the pull rod 325 also allows the rigidity of the housing 300.

[0043] Regardless of the embodiment, the openings of the housing may all be identical.

[0044] Regardless of the embodiment, the slots of the movable ring may all be identical.

[0045] Advantageously, the slots of the movable ring and the openings of the housing have the same 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 that coincides with the opening of the housing, and to move the movable ring only by the amplitude of its slot so that it can completely open or completely close the opening of the housing and therefore also the slot of the housing handling structure.

[0046] Regardless of the embodiment, the housing may have an integral structure.

[0047] Independently of the embodiment, the number of openings in the housing (and therefore 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 range of values, all possibilities can therefore be covered.

[0048] Regardless of the embodiment, the housing and the movable ring can be made of the same material. This enables the two components to be subjected to the same thermal and mechanical stresses, thereby ensuring that even in the event of thermal expansion, opening or closing of the housing handling structure will always be possible.

[0049] Alternatively, the housing and the movable ring may be made of different materials, but the two materials must have close, or even identical, physical properties so that they have similar thermal expansion.

[0050] The expression "between ... and / or ..." should be interpreted as including these extreme values.

Claims

1. A compressor (310) casing (100, 200, 300) of a gas turbine engine, comprising openings (201) cut in the thickness of the casing from an inner surface (1001, 2001, 3001) of the casing, the openings being arranged side by side on the circumference of the casing, characterized in that The shell also includes a movable ring (120, 220, 320) formed by at least two annular parts (121, 122, 321, 322), positioned on the outer surface (1002, 2002, 3002) of the shell opposite to the opening, and capable of moving along the circumference of the shell so as to open or close the opening of the shell to enable or disable the shell processing structure, the movable ring including the same number of slots (202) as the openings present in the shell.

2. The compressor casing (100, 200, 300) according to claim 1, wherein: Each opening (201) of the housing has a width greater than or equal to the width of an associated slot (202) of a movable ring (120, 220, 320), and each opening of the housing has a length greater than or equal to the length of an associated slot of the movable ring.

3. The compressor casing (300) according to claim 1 or 2, further comprising at least one spring (340) assembling the movable ring (320) to the casing, the spring being configured such that when the spring is not stressed, the opening of the casing is open.

4. The compressor casing (300) according to any one of claims 1 to 3, comprising an electric motor (330), the electric motor comprising a camshaft (332), the camshaft (332) being configured to move a movable ring along the circumference of the casing so that the movable ring opens or closes an opening of the casing.

5. A compressor casing according to any one of claims 1 to 3, comprising an actuator configured to move the movable ring along the circumference of the casing so as to open or close the opening of the casing.

6. The compressor casing according to any one of claims 1 to 5, wherein: The size of the slot of the movable ring is the same as the size of the opening of the housing.

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

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

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