TREATMENT OF A NON-AXIS-SYMMETRICAL HOUSING WITH CONTROLLED OPENING

Description

Technical Field

[0001] The present invention relates to the general field of turbomachinery compressors, and more particularly to the treatment of the casing of turbomachinery compressors. Previous technique

[0002] Turbomachine compressors consist of blades driven in rotation inside a casing which ensures the air stream is sealed from the outside of the engine.

[0003] It is known that the play existing between the ends of the moving blades of the compressor and the casing forming the inner wall of the air flow duct degrades the efficiency of the turbomachine engine.

[0004] Furthermore, this play can alter and degrade the compressor's operation, potentially leading to a surge phenomenon resulting from the airflow separating from the blade surface. Controlling the airflow at the blade tips is crucial for achieving both good aerodynamic efficiency of the compressor and a sufficient margin against surge.

[0005] To limit the impact of this parasitic flow between the blade tips and the casing, the internal surface of the casing can be treated locally by creating cavities within its thickness opposite the blades. Documents FR 2 989 742, GB 2 408 546, US2003002982, and US 2016 / 153465 provide examples of casing treatment.

[0006] However, the pumping phenomenon only occurs when the compressor is heavily loaded, that is, when it is operating at the upper end of its operating range. Outside this zone, crankcase treatments are therefore no longer effective and can even lead to a loss of compressor efficiency.

[0007] It is therefore desirable to have a compressor housing in which the slots of the housing treatment can be closed or opened to avoid the pumping phenomenon while maintaining good compressor efficiency. Description of the invention

[0008] The invention relates to a turbomachine compressor housing comprising openings cut into the thickness of the housing from an internal face of the housing and arranged next to each other on a circumference of the housing, characterized in that it also comprises a movable ring, formed by at least two annular portions, present on an external face of the housing opposite the openings and capable of moving along the circumference of the housing so as to close and open the openings of the housing to activate or deactivate a housing treatment, the movable ring comprising the same number of slots as openings in the housing.

[0009] When the openings in the casing align with the slots in the rotating ring—that is, when the casing openings are opposite the rotating ring slots—the openings on the casing form the slots of a non-axisymmetric casing treatment. This is because they are located along the circumference of the casing and open onto the groove. In other words, they form axial slots arranged in an azimuthal direction and are therefore non-axisymmetric with respect to the compressor's axis of rotation. Axisymmetric casing treatments, on the other hand, consist of circumferential grooves and are symmetrical with respect to the compressor's axis of rotation.

[0010] Thanks to the invention, the slots in the crankcase treatment can be opened or closed using the movable ring. This allows for active crankcase treatment when operating conditions require it, for example during takeoff, to prevent surge, and inactive crankcase treatment when the compressor is no longer under load, for example during cruise, to maximize compressor efficiency. Thus, the invention allows control over the opening of the crankcase treatment.

[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 includes at least one spring assembling the movable ring to the housing configured so that the openings in the housing are open when the spring is at rest.

[0013] The spring allows the movable ring to return to an initial position or a safety position, in which its slots are opposite the openings in the housing, so that the slots in the housing treatment are fully open for the housing treatment to be active.

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

[0015] The camshaft allows the moving ring to be moved along the circumference of the crankcase, and more specifically the cam allows the moving ring to be moved by an amplitude at least equal to the width of an opening in the crankcase so as to open or close the openings in the crankcase completely, and therefore so as to open or close the slots in the crankcase treatment completely.

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

[0017] The actuator can perform the same function as the camshaft, thus moving the movable ring along the circumference of the crankcase to open or close the slots in the crankcase treatment. It allows the movable ring to be moved by an amplitude at least equal to the width of a crankcase opening.

[0018] According to another particular feature of the invention, the dimensions of the slots in the movable ring and the openings in the housing are equal.

[0019] This means that the slots in the movable ring and the openings in the housing are the same length and width. This makes opening and closing the slots in the housing treatment easier, because by moving the movable ring the width of a housing opening, the corresponding slot in the housing treatment can be fully opened or closed.

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

[0021] According to another particular feature of the invention, the movable ring and the housing are made of the same material. Brief description of the drawings

[0022] Other features and advantages of the present invention will become apparent from the description given below, with reference to the attached drawings which illustrate examples of embodiment without any limiting character. [ Fig. 1 ] There figure 1 represents, schematically and partially, a turbomachine compressor housing according to an embodiment of the invention. Fig. 2A ] There figure 2A represents, schematically and partially, the closed slots of the compressor housing treatment of the figure 1 . [ Fig. 2B ] There figure 2B represents, schematically and partially, the open slots of the compressor housing treatment of the figure 1 . [ Fig. 3 ] There figure 3 represents, schematically and partially, a turbomachine compressor housing according to another embodiment of the invention. Description of the implementation methods

[0023] There figure 1 represents, schematically and partially, a turbomachine compressor housing 100 according to a first embodiment of the invention.

[0024] The housing 100 includes openings cut (or shaped) in the thickness of the housing from the inner face 1001 of the housing 100. The openings are arranged next to each other on the circumference of the housing 100.

[0025] The housing 100 also includes a movable ring 120 located on its outer face 1002. The movable ring 120 has the same number of slots as the openings in the housing 100 and can move along the circumference of the housing 100 so as to open or close the openings in the housing 100 by means of its own slots. By aligning the slots of the movable ring 120 with the openings in the housing 100—that is, when the slots of the movable ring 120 are opposite the openings in the housing 100—a housing treatment is formed in which the slots are open when the openings in the housing 100 are open. In other words, the movable ring 120 rotates around the housing 100 so as to open or close the openings in the housing 100.

[0026] Each opening in the housing 100 has a width greater than or equal to the width of the associated slot in the movable ring 120 (or the slot opposite said opening), and each opening in the housing 100 has a length greater than or equal to the length of the associated slot in the movable ring 120 (or the slot opposite said opening). This ensures that the openings in the housing 100 are fully open when the housing treatment is to be activated.

[0027] 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 the housing treatment is to be deactivated.

[0028] The movable ring 120 is formed of two annular portions 121 and 122. In this first embodiment, the two annular portions 121 and 122 are assembled together by a pointed screw 130, but they can, instead, be assembled by any other means of assembly, for example a system composed of a centering pin and a screw and nut assembly for holding in position.

[0029] Having a movable ring 120 formed of at least two annular portions 121 and 122 makes it easier to mount the movable ring 120 on the housing 100.

[0030] The housing 100 includes a piston 140 fixed at one end to the movable ring 120 and at the other end to the housing 100 by means of a guide pin 125. The piston 140 controls the movement of the movable ring 120 along the circumference of the housing 100, allowing it to be moved by an amplitude at least equal to the width of the openings in the housing 100 to fully open and / or close these openings and thus the slots in the housing treatment. The guide pin 125 stiffens the housing 100 and provides a fixed point for attaching the piston 140.

[0031] To move the movable ring 120 on the housing 100, the piston 140 can be replaced by an actuator.

[0032] THE figures 2A And 2B represent a cross-sectional view of the 201 open openings ( figure 2B ) or closed ( figure 2A ) of the 200 crankcase figure 1 thanks to the movement of the movable ring 220 and its slots 202. As indicated with reference to the figure 1 The openings 201 of the housing 200 are cut (or machined) into the thickness of the housing 200 from its inner face 2001 and are arranged side by side around the circumference of the housing 200. The movable ring 220 has the same number of slots 202 as there are openings 201 in the housing 200 and is positioned on the outer face 2002 of the housing 200 so that it can open or close the openings 201 of the housing 200 by moving along the circumference of the housing 200. In this embodiment, the slots 202 of the movable ring 220 have the same width and length as the openings 201 of the housing 200. Furthermore, the distance between the openings 201 of the housing 200 is identical to the distance between the slots 202 of the movable ring. 220. Thus, 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 open ( figure 2B ) and the slots in the crankcase treatment are open. When the slots 202 of the movable ring 220 cover the openings 201 of the crankcase 200, the openings 201 of the crankcase 200 are completely closed and the slots in the crankcase treatment are closed ( figure 2A ). The treatment of crankcase 200 is therefore inactive in the case of the figure 2A (closed crankcase treatment slots) and it is active in the case of the figure 2B (open crankcase treatment slots).

[0033] There figure 3 represents, schematically and partially, a compressor housing 300 of a turbomachine 310 according to a second embodiment of the invention.

[0034] As indicated with reference to the figure 1 The housing 300 includes openings cut or shaped in the thickness of the housing 300 from the inner face 3001 of the housing 300. The openings are arranged next to each other along the circumference of the housing 300.

[0035] The housing 300 also includes a movable ring 320 located on the outer face 3002 of the housing 300. The movable ring 320 has the same number of slots as the openings in the housing 300 and can move along the circumference of the housing 300 so as to open or close the openings in the housing 300 by means of its own slots to open or close the slots in the housing treatment. As indicated with reference to the figure 1 Each opening in the housing 300 has a width greater than or equal to the width of the associated slot in the movable ring 320, and each opening in the housing 300 has a length greater than or equal to the length of the associated slot in the movable ring 320. In addition, the distance between each opening in the housing 300 is greater than or equal to the width of the associated slot in the movable ring 320.

[0036] The movable ring 320 is formed of two annular portions 321 and 322. As previously stated, the two annular portions 321 and 322 can be assembled together by a pointed screw or by any other means of assembly.

[0037] To move the movable ring 320 and open or close the slots in the housing treatment, and thus the openings in the housing 300, the housing 300 includes an electric motor 330 comprising a camshaft 332. By pivoting, the cam 332 moves the movable ring 320 along the circumference of the housing 300. The cam 332 can bear against a projecting portion 326 on one of the annular portions 322 to pivot and move the movable ring 320. The electric motor 330 and the camshaft 332 allow the movable ring 320 to be moved by at least an amplitude equal to the width of an opening in the housing 300. A pin 327 may be present to lock the projecting portion 326 during the movement of the movable ring 320.

[0038] The housing 300 may also include a spring 340 attached to the movable ring 320 and to the housing 300 by means of a column 325. This spring 340 is configured so that, at rest, the openings of the housing 300 are open, i.e., so that the slots of the movable ring 320 do not obstruct the openings of the housing 300 (case of the figure 2B ) so that the crankcase treatment is active. As before, the 325 post also helps to stiffen the 300 crankcase in addition to forming a fixed point for attaching the 340 spring.

[0039] Regardless of the method of implementation, the openings in the casing can all be identical.

[0040] Regardless of the embodiment, the slots in the moving ring can all be identical. Advantageously, the slots in the moving ring and the openings in the housing have the same dimensions, i.e., they have the same length and width; and the distance between the openings in the housing is equal to the distance between the corresponding slots in the moving ring. This allows the slots in the moving ring to coincide with the openings in the housing, and the moving ring only needs to be moved by the amplitude of its slots to fully open or close the openings in the housing and thus the slots in the housing treatment.

[0041] Regardless of the method of construction, the casing can be a single piece.

[0042] Regardless of the embodiment, the number of openings in the housing (and therefore in the rotating ring) ranges from 40 to 850, for example, from 45 to 810, or from 60 to 210. This is because the housing treatment requires between 3 and 8 slots per rotor blade, and a rotor comprises between 15 and 90 blades. This range of values ​​thus covers all possibilities.

[0043] Regardless of the specific design, the housing and the moving ring can be made of the same material. This allows both parts to be subjected to the same thermal and mechanical stresses, thus ensuring that opening or closing the housing treatment will always be possible, even in the event of thermal expansion.

[0044] Alternatively, the casing and the moving ring can be made of different materials, but it is necessary that these two materials have similar or even identical physical properties so that their thermal expansion is similar.

[0045] The expression "between ... and ..." should be understood as including the boundaries.

Claims

1. A casing (100, 200, 300) of a gas turbine engine compressor (310) comprising openings (201) cut in the thickness of the casing from an inner surface (1001, 2001, 3001) of the casing and arranged side by side over a circumference of the casing, characterised in that it also comprises a movable ring (120, 220, 320), formed by at least two annular portions (121, 122, 321, 322), positioned on an outer surface (1002, 2002, 3002) of the casing opposite the openings and able to move along the circumference of the casing such as to open or close the openings of the casing to activate or deactivate a casing treatment, the movable ring comprising the same number of slots (202) as there are openings in the casing.

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

3. The compressor casing (300) according to either of claims 1 or 2, also comprising at least one spring (340) assembling the movable ring (320) onto the casing, configured so that the openings of the casing are open when the spring is unstressed.

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

5. The compressor casing according to any of claims 1 to 3, comprising an actuator configured to move the movable ring along the circumference of the casing such as to open or close the openings of the casing.

6. The compressor casing according to any of claims 1 to 5, wherein the dimensions of the slots of the movable ring and of the openings of the casing are the same.

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

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