Air distribution box

Abstract

An air distribution housing of a system (2) for cooling a turbomachine casing, the housing comprising: - walls (4, 4a, 4b, 4c) defining an internal volume, - a plurality of connections (16) opening into the internal volume and configured to be coupled to cooling tubes (17) having cooling orifices configured to cool the casing, - a mouth (20) delimiting a supply opening (22) of the internal volume, the mouth (20) being configured to be connected to an air supply tube of the internal volume, in which the walls (4, 4a, 4b, 4c) comprise two adjoining walls (4a, 4b) assembled together at a junction (6), the mouth (20) being mounted at the junction (6) between the two adjoining walls (4a, 4b), and comprising a groove in which at least one adjoining wall (4a, 4b) is inserted. Figure for abstract: Figure 3

Description

Title of the invention: Air distribution box Technical field

[0001] The present invention relates to the field of turbomachines, in particular for aircraft, and more particularly concerns an air distribution housing of a cooling system of a turbomachine casing. State of the art

[0002] Cooling systems of the LPTCC type (Low Pressure Turbine Clearance Control) are known. The LPTCC system can be controlled by the FADEC (Full Authority Digital Engine Control, which designates a full authority digital engine regulator for aircraft engines); this is called active control, the system then being designated by the acronym LPTACC. When it is not controlled by the FADEC, the LPTCC system is called passive control. Its main function is to regulate the rotor / stator clearance between the parts of the low pressure turbine by modulating the flow of air taken from the secondary flow for cooling the low pressure turbine casing.

[0003] As illustrated in [Fig.l], to ensure the cooling of certain casings, and in particular low-pressure turbine casings, a cooling system 2 is provided which comprises a set of cooling tubes 17, also called cooling ramps, pierced with holes and arranged outside the casing, most often surrounding said casing, such that air, sucked upstream of the turbomachine relative to the direction of flow of the gases in the turbomachine, is sent to the external face of the casing. The cooling system 2 may further comprise several air distribution boxes 100, for example four boxes 100, arranged around the casing to supply air to the cooling tubes 17.

[0004] Each housing 100 is supplied with air by a supply tube (not shown) engaging with a mouth 120 of the air distribution housing 100. This mouth is brazed to the upper part 140 of the housing 100, which is itself brazed to the lateral flanks 142. The lower part 144 of the housing 100 is also brazed to the lateral flanks. Typically, the upper part 140 and the lower part 144 are flat and cover flanges of the lateral flanks 142, generally formed by a curvature of the edges of these lateral flanks 142, as shown diagrammatically in [Fig. 2]. The cooling tubes 17 are connected to the housing 100 by connections 116.

[0005] By way of example, patent application FR3129972 describes an example of a housing for distributing cooling air on a low-pressure turbine casing of a turbomachine, and patent application FR2977276 describes an arrangement for connecting at least one duct with an air distribution housing.

[0006] In operation, the cooling system is subjected to high temperatures in a non-uniform manner. This results in high thermal expansion. Furthermore, in the case of an aircraft turbomachine, the cooling system is subjected to high vibrations. The brazing holding the mouth to the housing may become weakened. Since the feed tube of the mouth 120 of the housing applies a tensile force to the mouth of the housing, tearing of the mouth 120 may occur when the brazing is not strong enough.

[0007] Attempts have been made to strengthen these solders, but the aging of these solders requires periodic monitoring of the condition of the boxes, and possibly their preventive replacement, which increases aircraft maintenance.

[0008] The tearing of a mouth 120 from a housing results in a leak of cooling air associated with a loss of pressure in the cooling system. This loss of pressure reduces the capacity of the cooling system to effectively cool the casing. Thermal expansions can then appear, which can significantly harm the performance of the turbomachine, in particular when these expansions affect the radial clearances of the turbine, the control of which in operation improves the efficiency of the turbine. Presentation of the invention

[0009] The present invention aims to remedy the drawbacks of the state of the art, by ensuring the robustness of the cooling of the casing allowing efficient control of the turbomachine thanks to the preservation of the radial clearances of the turbine.

[0010] To this end, the invention proposes an air distribution housing for a cooling system of a turbomachine casing, the housing being configured to be mounted around the casing, the casing being centered on a turbomachine axis and the housing comprising: - walls defining an internal volume, - a plurality of connections opening into the internal volume and configured to be coupled to cooling tubes intended to extend circumferentially around the turbomachine axis in order to supply air to said cooling tubes, the cooling tubes having cooling orifices configured to cool the casing, - a mouth delimiting a supply opening of the internal volume, the mouth being configured to be connected to an air supply tube of the internal volume, characterized in that the walls comprise two adjoining walls assembled together at a junction, the mouth being mounted at the junction between the two adjoining walls, and comprising a groove into which at least one adjoining wall is inserted.

[0011] The invention is advantageously supplemented by the following characteristics, taken alone or in any of their technically possible combinations: - the two adjoining walls are inserted into a groove in the mouth; - the two adjoining walls are inserted into the same groove of the mouth, and the groove extends over a perimeter of the mouth; - the mouth is part of the junction between the two adjoining walls and separates the two adjoining walls by delimiting the supply opening of the internal volume; - the two adjoining walls form a radially external face of the housing opposite a radially internal face of the housing, the radially internal face of the housing being configured to be mounted opposite the casing; - the two adjoining walls further form a radially internal face of the housing, the adjoining walls also being assembled together at the junction to form the radially internal face; - at least one adjoining wall is secured to the mouth; - the connection between the two adjoining walls and the mouth is achieved by brazing or welding.

[0012] The invention also relates to a cooling system for a turbomachine casing, comprising: - an air distribution box according to the invention, - cooling tubes having cooling ports configured to cool the housing and the cooling tubes being connected to the plurality of connections of the housing, - an air supply tube connected to the mouth of the housing. The invention also relates to a turbomachine for aircraft comprising a cooling system according to the invention. Brief description of the drawings

[0013] The invention will be better understood from the following description, which relates to a preferred embodiment, given as a non-limiting example and explained with reference to the appended schematic drawings, in which:

[0014] - [Fig.l], already discussed, shows an overview of an example of a housing of air distribution according to the state of the art,

[0015] - [Fig.2], already discussed, schematically illustrates a section of an example of air distribution box according to the state of the art,

[0016] - [Fig.3] is a perspective view showing an overall view of a housing of air distribution according to a possible embodiment of the invention,

[0017] - [Fig.4] schematically illustrates a section of an example of a dis housing air supply according to a possible embodiment of the invention,

[0018] - [Fig.5] is a perspective view showing a mouth mounted on a housing of air distribution according to a possible embodiment of the invention,

[0019] - [Fig.6] is a side view of the mouth and housing of [Fig.5]. Detailed description

[0020] As already discussed above, the air distribution housing of a cooling system of a turbomachine casing is configured to be mounted around the casing, the casing being centered on a turbomachine axis. The housing is connected to cooling tubes extending circumferentially around this axis, and which have cooling orifices configured to cool the casing.

[0021] With reference to [Fig. 3] and [Fig. 4], the air distribution housing 1 of a system 2 for cooling a turbomachine casing comprises walls 4 defining an internal volume. These walls 4 are configured to withstand the operating conditions in an aircraft, and are typically metallic, for example stainless steel. The walls 4 comprise two adjoining walls 4a, 4b which are assembled or coupled together by a junction 6. The two adjoining walls 4a, 4b are thus secured by the junction 6.

[0022] In the illustrated example, the junction 6 is on an outer side 8 (radially outer relative to the casing, or upper side) opposite an inner side 10 (radially inner relative to the casing, or lower side) configured to face the casing, and the adjoining walls 4a, 4b are side walls. Each adjoining wall 4a, 4b is curved so as to have a side face 12a, 12b and an outer face 14a, 14b. In this example, the adjoining walls 4a, 4b are joined by their outer faces 14a, 14b, on the outer side 8. Preferably, each side face 12a, 12b and each outer face 14a, 14b are predominantly planar, and connected by a curve. Other shapes can however be envisaged. In particular, the junction 6 might not be on an outer side, but on one side of the housing, and the two adjoining walls might be an outer wall and an inner wall.

[0023] Preferably, this junction 6 is rectilinear over the majority of its length. As seen in [Fig.4], the edges of the two adjoining walls 4a, 4b are aligned and face each other, and are assembled for example by brazing or welding.

[0024] The housing 1 comprises a plurality of connections 16 opening into the internal volume through a wall 4, and more precisely a lateral face 12a, 12b of the adjoining walls 4a, 4b of the housing 1. These connections 16 are configured to be coupled to cooling tubes 17 in order to supply air to said cooling tubes 17, the cooling tubes 17 having cooling orifices configured to cool the casing, arranged on their inner part facing the casing. Preferably, and as illustrated in [Fig. 3], these connections 16 are located on each adjoining wall 4a, 4b, and more precisely on the lateral face 12b of each adjoining wall 4a, 4b. These connections can take the form of flanges or sockets projecting from the adjoining wall 4a, 4b and on which the cooling tubes can be fixed, but other forms could be envisaged, such as for example openings arranged in a wall 4.

[0025] The housing 1 may comprise attachment or fixing means, for example flanges 18, by which the housing 1 can be fixed in the turbomachine, for example to the casing, typically using screws or bolts, or any other fixing member.

[0026] Preferably, the two adjoining walls 4a, 4b form an outer face of the housing opposite an inner face of the housing, the inner face of the housing being configured to be mounted facing the casing. The outer face is on the outer side 8, and the inner face is on the inner side 10 opposite the outer side 8.

[0027] The walls 4 may further comprise an inner wall 4c on the inner side 10 opposite the outer side 8. This inner wall 4c is configured to face the casing, and the adjoining walls 4a, 4b are each assembled to the inner wall 4c, preferably by brazing or welding.

[0028] The housing 1 also comprises a mouth 20 delimiting a supply opening 22 of the internal volume, putting the internal volume in communication with the exterior. This mouth 20 is configured to be connected to an air supply tube to bring air into the internal volume. The mouth 20 is mounted at the junction 6 between the two adjoining walls 4a, 4b. Alternatively, the two adjoining walls 4a, 4b can further form the inner face of the housing on the inner side 10 opposite the outer side 8, and intended to face the casing. The adjoining walls 4a, 4b are then also assembled and secured to form this inner face with a junction, for example brazed or welded.

[0029] In the example illustrated, the junction 6 is on the outer side 8, and therefore the mouth 20 is mounted on the outer side 8. If the junction 6 is on a lateral side 7 between the outer side 8 and the inner side 10, the mouth is then mounted on this lateral side 7, on the side of the connections 16. The connection between the two adjoining walls 4a, 4b and the mouth 20 is for example achieved by brazing or welding, preferably around the entire circumference of the mouth 20.

[0030] The mouth 20 is part of the junction 6 between the two adjoining walls 4a, 4b, and separates the two adjoining walls 4a, 4b at the level of the supply opening 22. arranged in the two adjoining walls 4a, 4b. The junction 6 delimits the mouth 20 in the walls 4.

[0031] The mouth 20 can locally interrupt the rectilinear appearance of the junction 6. In particular, the mouth 20 may have a circular section, and the junction 6 goes around this circular section. Each adjoining wall 4a, 4b may therefore have a notch or cutout corresponding to the feed opening 22. Preferably, the mouth 20 is centered relative to the junction 6, and the feed opening 22 is distributed equally between the two adjoining walls 4a, 4b, the cutout in each adjoining wall 4a, 4b corresponding to approximately half of the feed opening 22. When the feed opening 22 is of circular section, each adjoining wall has a notch or cutout in the shape of an arc of a circle, and for example in a semicircle.

[0032] The mouth 20 comprises a groove 24 in which at least one contiguous wall 4a, 4b is inserted. Preferably, the two contiguous walls 4a, 4b are inserted into a groove 24 of the mouth 20. Typically, the groove 24 extends along the periphery of the mouth 20, and the two contiguous walls 4a, 4b are inserted into the same groove 24 of the mouth 20.

[0033] The groove 24 is defined between two flanges 24a, 24b extending parallel to the edges of the adjoining walls 4a, 4b inserted therein. The width of the groove 24 is chosen to be similar to the thickness of the edges of the adjoining walls 4a, 4b inserted therein, so that the engagement in the groove 24 maintains the adjoining walls 4a, 4b and prevents them from moving in the groove 24: the clearance is preferably reduced to a minimum, however allowing the insertion of the edges of the adjoining walls 4a, 4b.

[0034] The assembly of the mouth 20 to the adjoining walls by means of the groove 24 allows a high resistance to tearing of the mouth 20, and, by limiting the stresses on the edges of the adjoining walls 4a, 4b inserted in the groove 24, allows to limit the aging of the assembly (for example the brazing or the welding) which maintains the mouth 20.

[0035] The mouth 20 has a shape adapted to the fixing of the air supply tube, and for example has an attachment zone 26 delimited by an area of ​​enlarged section 28. The attachment zone 26 is characterized by a smaller section than the section of the area of ​​enlarged section 28. The air supply tube covers the attachment zone 26 and the area of ​​enlarged section 28, and a fixing device such as a collar, for example in a V, tightens the air supply tube against the attachment zone 26, and the area of ​​enlarged section 28 holds the fixing device.

[0036] The proposed structure is simple to manufacture, particularly for the example illustrated. Starting from a first adjoining wall 4a, the mouth 20 is mounted in the cutout of the adjoining wall 4a, the edge of which matches the shape of the groove 24 and is there inserted. A second adjoining wall 4b is then mounted against the first adjoining wall, the edge of the second adjoining wall 4b being aligned and facing the edge of the first adjoining wall 4a. The edge of the second adjoining wall 4b is inserted into the groove 24 of the mouth 20. The first adjoining wall 4a and the second adjoining wall 4b are then assembled, for example by brazing or welding. At least one adjoining wall 4a, 4b is secured to the mouth 20. Typically, the mouth 20 is assembled to the two adjoining walls 4a, 4b, for example by brazing or welding. The mouth 20 can be assembled to the first contiguous wall 4a inserted in the groove 24 before the second contiguous wall 4b is placed in the groove 24. Preferably, a brazing or soldering extends along the junction 6 between the two contiguous walls 4a, 4b. The brazing or soldering makes it possible to ensure both mechanical support of the housing 1 and sealing of the housing 1.

[0037] The proposed housing 1 makes it possible in particular to ensure that two brazing joints are not close together, which could weaken the housing 1. In the example of [Fig. 1], the brazing joint on the periphery 122 passes close to the junction 124 brazed between the outer wall 140 and the side wall 142. This results in a weak point in the housing 100, which can become deformed or broken, and no longer ensure the maintenance of the mouth 120. On the contrary, in the present invention, the rectilinear part 6a of the junction 6 between the two adjoining walls 4a, 4b joins perpendicularly the part 6b of the junction 6 between the mouth and the two adjoining walls 4a, 4b. This results in greater resistance of the housing 1, limiting the risk of tearing off the mouth 20.

[0038] The invention is not limited to the embodiment described and shown in the attached figures. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. Housing (1) for distributing air in a system (2) for cooling a turbomachine casing, the housing being configured to be mounted around the casing, the casing being centered on a turbomachine axis and the housing comprising: - walls (4, 4a, 4b, 4c) defining an internal volume, - a plurality of connections (16) opening into the internal volume and configured to be coupled to cooling tubes (17) intended to extend circumferentially around the turbomachine axis in order to supply air to said cooling tubes (17), the cooling tubes (17) having cooling orifices configured to cool the casing, - a mouth (20) delimiting a supply opening (22) of the internal volume, the mouth (20) being configured to be connected to an air supply tube of the internal volume, characterized in that the walls (4, 4a, 4b, 4c) comprise two adjoining walls (4a,4b) assembled together at a junction (6), the mouth (20) being mounted at the junction (6) between the two adjoining walls (4a, 4b), and comprising a groove (24) in which at least one adjoining wall (4a, 4b) is inserted.,

2. Housing according to claim 1, in which the two adjoining walls (4a, 4b) are inserted into a groove (24) of the mouth (20).

3. A housing according to claim 2, wherein the two adjoining walls (4a, 4b) are inserted into the same groove (24) of the mouth (20), and the groove (24) extends over a perimeter of the mouth (20).

4. Housing according to any one of the preceding claims, in which the mouth (20) forms part of the junction (6) between the two adjoining walls (4a, 4b) and separates the two adjoining walls (4a, 4b) by delimiting the supply opening (22) of the internal volume.

5. Housing according to any one of the preceding claims, in which the two adjoining walls (4a, 4b) form a radially external face of the housing opposite a radially internal face of the housing, the radially internal face of the housing being configured to be mounted opposite the casing.

6. Housing according to claim 5, in which the two adjoining walls (4a, 4b) further form a radially internal face of the housing, the adjoining walls (4a, 4b) also being assembled together at the junction (6) to form the radially internal face.

7. Housing according to any one of the preceding claims, in which at least one adjoining wall (4a, 4b) is secured to the mouth (20).

8. Housing according to any one of the preceding claims, in which the connection between the two adjoining walls (4a, 4b) and the mouth (20) is achieved by brazing or welding.

9. System (2) for cooling a turbomachine casing, comprising: - an air distribution housing (1) according to any one of the preceding claims, - cooling tubes (17) having cooling orifices configured to cool the casing and the cooling tubes (17) being connected to the plurality of connections of the housing (1), - an air supply tube connected to the mouth (20) of the housing (1).

10. 10. Aircraft turbomachine comprising a cooling system according to claim 9.

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