Air distribution box

Abstract

An air distribution box of a cooling system (2) for a turbomachine casing, the box 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, - an outlet (20) delimiting a supply opening (22) of the internal volume, the outlet (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 contiguous walls (4a, 4b) assembled together at a junction (6), the outlet (20) being mounted at the junction (6) between the two contiguous walls (4a, 4b), and comprising a groove into which at least one contiguous wall (4a, 4b) is inserted. Figure for the summary: Figure 3

Description

Title of the invention: Air distribution unit technical field

[0001] The present invention relates to the field of turbomachinery, particularly for aircraft, and more particularly concerns an air distribution box for 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 controller for aircraft engines); this is then referred to as active control, and the system is designated by the acronym LPTACC. When it is not controlled by the FADEC, the LPTCC system is referred to as passive control. Its main function is to regulate the rotor / stator clearance between the parts of the low-pressure turbine by modulating the airflow drawn from the secondary flow for cooling the low-pressure turbine casing.

[0003] As illustrated in [Fig. 1], to ensure the cooling of certain housings, and in particular low-pressure turbine housings, a cooling system 2 is provided which comprises a set of cooling tubes 17, also called cooling manifolds, perforated with holes and arranged on the outside of the housing, most often surrounding said housing, such that air, drawn upstream of the turbomachine relative to the direction of gas flow in the turbomachine, is directed towards the outer face of the housing. The cooling system 2 may further comprise several air distribution boxes 100, for example four boxes 100, arranged around the housing to supply air to the cooling tubes 17.

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

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

[0006] During operation, the cooling system is subjected to high temperatures in a non-uniform manner. This results in significant thermal expansion. Furthermore, as it is an aircraft turbomachine, the cooling system is subjected to strong vibrations. The brazing that secures the nozzle to the housing can be weakened. Since the feed tube of the housing nozzle 120 applies a tensile force to the housing nozzle, the nozzle 120 can be torn off if the brazing is not sufficiently strong.

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

[0008] The removal of a 120 inlet from a housing results in a cooling air leak associated with a pressure loss in the cooling system. This pressure loss reduces the cooling system's ability to effectively cool the housing. Thermal expansion can then occur, which can significantly impair the turbomachine's performance, particularly when this expansion affects the turbine's radial clearances, the control of which during operation improves turbine efficiency. Presentation of the invention

[0009] The present invention aims to remedy the drawbacks of the prior 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 turbomachine housing cooling system, the housing being configured to be mounted around the housing, the housing being centered on a turbomachine shaft 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 crankcase, - a vent defining an opening for supplying air to the internal volume, the vent being configured to be connected to an air supply tube for the internal volume, characterized in that the walls comprise two adjoining walls joined 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 complemented by the following features, taken alone or in any technically possible combination thereof: - 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 also 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 attached to the mouth; - the joining 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 turbine housing, comprising: - an air distribution unit according to the invention, - Cooling tubes with cooling ports configured to cool the crankcase, and the cooling tubes being connected to the plurality of connections on the housing, - an air supply tube connected to the mouth of the case. The invention also relates to an aircraft turbomachine 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 by way of non-limiting example and explained with reference to the accompanying schematic drawings, in which:

[0014] - Fig. 1, already discussed, shows an overview of an example of a housing air distribution according to the state of the art,

[0015] - Figure 2, already discussed, schematically illustrates a cross-section of an example of air distribution unit according to the state of the art,

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

[0017] - Fig. 4 schematically illustrates a cross-section of an example of a disc housing air distribution according to one possible embodiment of the invention,

[0018] - [Fig. 5] is a perspective view showing a mouth mounted on a housing air distribution according to one 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 turbomachine housing cooling system is configured to be mounted around the housing, the housing being centered on a turbomachine shaft. The housing is connected to cooling tubes extending circumferentially around this shaft, and which have cooling ports configured to cool the housing.

[0021] With reference to [Fig. 3] and [Fig. 4], the air distribution housing 1 of a turbomachine crankcase cooling system 2 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 joined or coupled together by a junction 6. The two adjoining walls 4a, 4b are thus joined by the junction 6.

[0022] In the illustrated example, the junction 6 is on an outer side 8 (radially outer with respect to the housing, or upper side) opposite an inner side 10 (radially inner with respect to the housing, or lower side) configured to face the housing, and the conjoining walls 4a, 4b are side walls. Each conjoining wall 4a, 4b is curved to have a side face 12a, 12b and an outer face 14a, 14b. In this example, the conjoining 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 mostly flat and connected by a curve. Other shapes may, however, be considered. In particular, junction 6 might not be on an outside side, but on a side of the case, and the two adjoining walls could be an outside wall and an inside wall.

[0023] Preferably, this junction 6 is straight along most of its length. As can be seen in [Fig. 4], the edges of the two adjoining walls 4a, 4b are aligned and face each other, and are joined, 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 specifically 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 are used to supply air to said cooling tubes 17. The cooling tubes 17 have cooling ports configured to cool the crankcase, located on their inner portion facing the crankcase. Preferably, and as illustrated in [Fig. 3], these connections 16 are located on each contiguous wall 4a, 4b, and more specifically on the lateral face 12b of each contiguous wall 4a, 4b. These connections may be in the form of flanges or sockets projecting from the contiguous wall 4a, 4b and to which the cooling tubes can be attached, but other forms could be considered, such as openings formed in a wall 4.

[0025] The housing 1 may include means for attaching or fixing, 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 device.

[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 include an inner wall 4c on the inner side 10 opposite the outer side 8. This inner wall 4c is configured to face the housing, and the adjoining walls 4a, 4b are each assembled to the inner wall 4c, preferably by brazing or welding.

[0028] The housing 1 also includes a vent 20 defining a supply opening 22 within the internal volume, connecting the internal volume to the outside. This vent 20 is configured to be connected to an air supply tube to bring air into the internal volume. The vent 20 is mounted at the junction 6 between the two adjoining walls 4a, 4b. Alternatively, the two adjoining walls 4a, 4b can also 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 joined to form this inner face with a junction, for example, brazed or welded.

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

[0030] The mouth 20 forms 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 formed in the two adjoining walls 4a, 4b. The junction 6 delimits the opening 20 in the walls 4.

[0031] The mouth 20 can locally interrupt the straight aspect of the junction 6. In particular, the opening 20 may have a circular cross-section, and the junction 6 follows this circular cross-section. Each adjoining wall 4a, 4b may therefore have a notch or cutout corresponding to the supply opening 22. Preferably, the opening 20 is centered with respect to the junction 6, and the supply opening 22 is distributed equally between the two adjoining walls 4a, 4b, the cutout in each adjoining wall 4a, 4b corresponding approximately to half of the supply opening 22. When the supply opening 22 has a circular cross-section, each adjoining wall has a notch or cutout in the shape of an arc, and for example, a semicircle.

[0032] The mouth 20 comprising a groove 24 into 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 holds the adjoining walls 4a, 4b and prevents them from moving in the groove 24: the clearance is preferably reduced to a minimum while still 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 pull-out 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 brazing or welding) which holds the mouth 20.

[0035] The mouth 20 has a shape adapted for attaching the air supply tube, and for example has an attachment zone 26 delimited by an enlarged cross-section zone 28. The attachment zone 26 is characterized by a smaller cross-section than the cross-section of the enlarged cross-section zone 28. The air supply tube covers the attachment zone 26 and the enlarged cross-section zone 28, and a fastening device such as a clamp, for example V-shaped, clamps the air supply tube against the attachment zone 26, and the enlarged cross-section zone 28 retains the fastening device.

[0036] The proposed structure is simple to manufacture, particularly for the illustrated example. Starting from a first contiguous wall 4a, the opening 20 is mounted in the cutout of the contiguous wall 4a, the edge of which follows the shape of the groove 24 and is A second adjoining wall 4b is then mounted against the first adjoining wall, with the edge of the second adjoining wall 4b aligned with 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 opening 20. The first adjoining wall 4a and the second adjoining wall 4b are then joined, for example by brazing or welding. At least one adjoining wall 4a, 4b is secured to the opening 20. Typically, the opening 20 is joined to the two adjoining walls 4a, 4b, for example by brazing or welding. The opening 20 can be joined to the first adjoining wall 4a inserted into the groove 24 before the second adjoining wall 4b is placed in the groove 24. Preferably, a braze or weld extends along the junction 6 between the two adjoining walls 4a, 4b. Brazing or welding ensures both mechanical support of housing 1 and sealing of housing 1.

[0037] The proposed housing 1 makes it possible, in particular, to prevent two brazed joints from being too close together, which could weaken the housing 1. In the example of [Fig. 1], the brazed joint around the perimeter 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 deform or break, and no longer secure the opening 120. On the contrary, in the present invention, the straight portion 6a of the junction 6 between the two adjoining walls 4a, 4b meets perpendicularly the portion 6b of the junction 6 between the opening and the two adjoining walls 4a, 4b. This results in greater strength of the housing 1, limiting the risk of the opening 20 being torn off.

[0038] The invention is not limited to the embodiment described and shown in the accompanying figures. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Demands

1. An air distribution housing (1) for a turbomachine casing cooling system (2), the housing being configured to be mounted around the casing, the casing being centered on a turbomachine shaft, 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 shaft to supply air to said cooling tubes (17), the cooling tubes (17) having cooling orifices configured to cool the casing, - an outlet (20) defining a supply opening (22) to the internal volume, the outlet (20) being configured to be connected to an air supply tube to 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) into 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. Housing according to claim 2, in which the two contiguous 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, wherein the mouth (20) is 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) from the internal volume.

5. Housing according to any one of the preceding claims, wherein the two contiguous 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 housing.

6. Housing according to claim 5, wherein the two adjoining walls (4a, 4b) further form a radially internal face of the housing, the adjoining walls (4a, 4b) also being assembled to each other 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 contiguous wall (4a, 4b) is attached to the mouth (20).

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

9. A turbomachine housing cooling system (2) comprising: - an air distribution housing (1) according to any one of the preceding claims, - cooling tubes (17) having cooling ports configured to cool the housing 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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