Device for cooling a turbine casing using air jets and turbine comprising such a device

Abstract

The present invention relates to an air jet cooling device (100) for a housing (48) of a turbine, particularly a housing of a low-pressure turbine (28), the air jet cooling device comprising at least one air supply shroud (120) and at least one cooling manifold (110) intended to be disposed around the housing to be cooled, the cooling manifold or each cooling manifold comprising two cooling tubes (112) disposed on both sides of the shroud, the supply shroud (120) comprising two side walls (125, 126), each side wall comprising an air outlet orifice (127), each orifice having a main axis and being configured and sized to receive an associated cooling tube, the cooling device comprising a fastening system intended to secure the cooling tubes to the housing, characterized in that each cooling tube is secured to the fastening system and is translatably movable along the main axis (P) within the associated orifice.

Description

Technical Field

[0001] This invention relates to an apparatus for cooling the casing of, for example, a low-pressure turbine used in a turbine using an air jet. The invention also relates to a turbine equipped with such a cooling apparatus.

[0002] This invention has applications in the aviation field, particularly in the field of cooling aircraft turbine housings. Background Technology

[0003] Prior art specifically includes documents FR3127012A1, EP3663534B1, FR3108932A1 and US2022 / 341347A1.

[0004] In the aerospace industry, the stator of a low-pressure turbine in a turbine mainly consists of a casing that requires cooling. One cooling technology uses impingement cooling. For this purpose, the casing is equipped with one or more pressurized air supply shrouds, each of which is connected to a cooling manifold that surrounds the casing and distributes cooling air around its entire perimeter.

[0005] Figure 1 A partial longitudinal cross-sectional view of the turbine 28A of the turbine 10A is shown. The turbine 10A is surrounded by a casing 48A cooled by a cooling device 100A.

[0006] Figure 2 A perspective view of such a device 100A for cooling a housing by means of an air jet, according to the prior art, is shown, wherein a turbine is not shown for simplicity. The cooling device 100A typically includes one or more cooling manifolds 110A connected to at least one air distribution shroud 120A. Figure 2 In the example shown, eight cooling manifolds 110A are illustrated, each connected between two air distribution shrouds 120A and positioned approximately 180° apart. Each cooling manifold 110A includes two tubes 112A extending parallel to each other at approximately 180° around the housing. Each tube of each cooling manifold 110A is penetrated by a series of holes that open opposite the outer surface of the housing. Pressurized air through these holes ensures impingement ventilation of the housing. Each cooling tube 112A has a perforation pattern that allows the housing to be cooled at multiple points to control the clearance between the movable impeller and the turbine housing, thereby optimizing engine efficiency.

[0007] Each air distribution hood 120A includes an air inlet compartment 122A connected to an outer pipe 130A, through which air flows to cool different components of the turbine. The air inlet compartment 122A delivers cooling air between the outer pipe 130A and the air distribution hood 120A.

[0008] In a known manner, the cooling pipe 112A is assembled and held in place by means of a manifold support 140A using a fastening clamp 142A configured to hold the cooling pipe 112A in place on the manifold support 140A. Figure 3 A cross-section of this manifold support and clamp is shown. Figure 4 A perspective view of this clamp is shown.

[0009] Manifold support 140A is fastened to the housing by a flange and is configured to keep the pipes spaced apart. More specifically, manifold support 140 is adapted to maintain a constant air gap between the air outlet orifice formed in the pipe and the outer surface of the housing, regardless of temperature, i.e., whether the turbine is stationary or in operation.

[0010] Cooling tube 112A is mounted in fastening clamp 142A, allowing cooling tube 112A to slide into the clamp. Fastening clamp 142A typically consists of a metal layer surrounded by two layers of braided silica coating coated with polytetrafluoroethylene (PTFE) to protect cooling tube 112A from metal-to-metal friction and to ensure that the tube slides in the clamp under optimal conditions.

[0011] However, during maintenance, damage to the cooling pipes was observed due to friction between the pipes and the clamps. In fact, during operation, the PTFE covering of the clamps tends to melt due to radiant heat from the upper low-pressure turbine casing, exceeding 350°C, the maximum operating temperature of PTFE. Once the PTFE loses contact, the silica braid deteriorates due to wear, and metal-to-metal contact exists between the clamp frame and the cooling pipes. This contact causes wear on the cooling pipes, sometimes to the point of perforation.

[0012] To date, no material for fastening clamps has been found that can protect the cooling pipes from contact with the clamp's silica cladding and withstand temperatures higher than the radiant heat of the low-pressure turbine housing at a "reasonable" price.

[0013] The object of this invention is to overcome at least some of the problems mentioned above. In particular, this invention provides a solution for ensuring the mechanical strength of a cooling manifold while ensuring the manufacturing integrity of the cooling pipe. Summary of the Invention

[0014] Therefore, the present invention relates to an apparatus for cooling a turbine housing, particularly a low-pressure turbine housing, using an air jet, the apparatus comprising at least one air supply shroud and at least one cooling manifold intended to be disposed around the housing to be cooled, the cooling manifold or each cooling manifold comprising two cooling tubes disposed on both sides of the shroud, the supply shroud comprising two side walls, each side wall comprising an air outlet orifice, each orifice having a main axis and being configured and sized to receive an associated cooling tube, the cooling apparatus comprising a fastening system intended to secure the cooling tubes to the housing, each side wall of the supply shroud comprising at least one sliding port disposed in one of the air outlet orifices, each sliding port being configured and sized to receive an associated cooling tube.

[0015] According to the invention, each cooling tube is fixed to the fastening system and is translatable along a main axis in an associated orifice, and each of the at least one sliding socket includes an inner cylindrical wall whose axis is the main axis of the associated air outlet orifice, and the inner cylindrical wall includes an annular groove for receiving a sealing element.

[0016] Therefore, the present invention proposes to fix the cooling pipe to a clamp on the manifold support so that the cooling pipe can be fixed in a way that prevents wear in this area. Thus, by allowing the cooling pipe to slide at its connection with the air distribution shroud, the tangential movement of the cooling pipe at the air distribution shroud is managed.

[0017] This cooling device according to the invention makes it possible to avoid removing the engine for maintenance, particularly for maintenance of the device, and thereby minimizes engine maintenance time by improving the mechanical strength of the cooling pipes in their clamps. The invention also improves engine robustness by eliminating the degradation of the interface between the cooling pipes and their fastening clamps due to friction and the degradation of the radial clearance of the turbine (particularly the low-pressure turbine) during operation.

[0018] The cooling device according to the invention may include one or more of the following features, either independently or in any technically possible combination: -The sealing element is a gasket, preferably an O-ring; - Each sliding socket forms a single component with the side wall; - The fastening system includes at least two supports for fastening the at least one manifold to the housing, each manifold support including at least one fastening clamp for fastening one of the pipes of the same manifold, the pipes being securely fastened to the fastening clamp, for example by brazing, welding or gluing. - The device includes at least two cooling manifolds, and each support of the fastening system is shaped to keep the manifolds spaced apart; - Each cooling tube is curved and designed to be positioned around a portion of the housing to be cooled and at a distance from said portion of the housing, and each cooling tube includes a plurality of orifices leading to the housing; - The inner cylindrical wall includes a coating to improve sliding; - The inner cylindrical wall is covered with a layer of graphite.

[0019] The present invention also relates to a turbine, particularly a low-pressure turbine, the turbine comprising a housing and equipped with a cooling device according to the present invention and as described above, using an air jet.

[0020] The present invention also relates to a turbine, particularly an aircraft turbine, which includes such a turbine or includes a housing and is equipped with a cooling device according to the present invention and as described above, using an air jet. Attached Figure Description

[0021] The invention will be better understood from the following description, given by way of non-limiting example and with reference to the accompanying drawings, and other details, features and advantages of the invention will become more apparent, in which: -Already described Figure 1 This is a schematic diagram of a partial longitudinal section of the turbine of a turbine. -Already described Figure 2 This is a schematic perspective view of an apparatus for cooling housing 120 using an air jet, according to the prior art; -Already described Figure 3 A schematic diagram of a longitudinal section of a fastening system for securing a cooling device manifold to a housing, according to the prior art, is shown. -Already described Figure 4 It is used for Figure 3 A schematic perspective view of the retaining clamp of the manifold of the fastening system shown; - Figure 5 This is a schematic partial cross-sectional view of a turbine equipped with a device for cooling the turbine housing according to the present invention; - Figure 6 A partial schematic perspective view of an apparatus according to the invention for cooling a housing using an air jet is shown; - Figure 7 yes Figure 6 An enlarged cross-sectional view of the connection area of ​​the cooling manifold in the distribution shroud of the cooling device; and - Figure 8 Shown from below for Figure 6 A schematic diagram of the manifold support component of the cooling device shown.

[0022] An example of an apparatus for cooling a low-pressure turbine housing using an air jet is described in detail below with reference to the accompanying drawings. This example illustrates the features and advantages of the invention. However, the invention is not limited to this example.

[0023] In the accompanying drawings, the same elements are labeled with the same reference numerals. These drawings are presented in an illustrative manner and in no way limit the scope of the invention. To facilitate readability, the dimensions of the elements shown are not taken into account. Detailed Implementation

[0024] First refer to Figure 5 , Figure 5 The diagram schematically illustrates a twin-shaft, twin-flow aircraft turbine 10 to which the present invention is applied. Of course, the present invention can be applied to other types of turbines equipped with electric motors, such as turboprop engines, without departing from the scope of the invention.

[0025] The turbine 10 has a longitudinal axis C around which various components of the turbine extend.

[0026] The turbine 10 typically includes a gas generator 12, with a fan 14 positioned upstream of the gas generator 12. The fan 14 is surrounded by a fan housing 16, which is surrounded by a nacelle 18 that surrounds and extends along the main portion of the gas generator 12.

[0027] Here, the gas generator 12 comprises two main bodies, namely a low-pressure body 12a or LP and a high-pressure body 12b or HP. Each main body includes a compressor and a turbine.

[0028] In this invention, the terms "upstream" and "downstream" are generally defined relative to the principal direction F of fluid flow within the turbine engine, and here along the longitudinal axis C (i.e., reference). Figure 1 Defined from left to right.

[0029] The gas generator 12 includes a low-pressure compressor 20, a high-pressure compressor 22, a combustion chamber 24, a high-pressure turbine 26, and a low-pressure turbine 28 from upstream to downstream.

[0030] The longitudinal axis C is the axis of rotation of the movable elements of the turbine engine 10, especially the axis of rotation of the turbines 26 and 28.

[0031] The fan 14 includes an annular row of blades 30 driven to rotate by a fan shaft 32, which is connected to the rotor of the low-pressure body 12a by means of a reduction gear 33. The airflow through the fan (arrow F) is split into a radially inner annular flow (referred to as the main flow 36) and a radially outer annular flow (referred to as the secondary flow 38) by an annular nose 34 upstream of the gas generator 12. The main flow 36 supplies the gas generator 12, and the secondary flow 38 flows between the gas generator 12 and the nacelle 18, providing most of the thrust of the turbine.

[0032] In the specification, the terms "inner" or "inner side" and "outer" or "outer side" are used non-limitingly to refer to the radial distance from the longitudinal axis C around which the turbine extends. The term "inner" defines the region radially closer to the longitudinal axis of the nacelle, as opposed to the term "outer". Furthermore, in the specification and claims, the terms "axial," "radial," and "lateral" are used with reference to the trihedrons A, R, and T shown in the accompanying drawings, where the axial axis A is parallel to the longitudinal axis C of the turbine.

[0033] The inlet housing 40 structurally connects the gas generator 12 to the fan housing 16 and the nacelle 18. The inlet housing 40 includes an annular array of radially inner arms 42 extending into the main flow 36, and an annular array of radially outer compressor stator blades 44 (OGV type) extending into the secondary flow 38. The number of arms 42 is typically limited (less than ten), and they are tubular and traversed by auxiliary devices. The number of blades 44 (OGV) is typically greater than ten.

[0034] Additionally, each turbine (particularly the low-pressure turbine 28) is surrounded by a housing 48, which is cooled by a cooling device 100 according to the invention and will be described in detail below. The housing 48 generally flares out from upstream to downstream and is substantially frustoconical. The housing includes an outer surface 21, an upstream end, and a downstream end.

[0035] Figure 6 A perspective view of such a cooling device 100 according to the invention for cooling a housing using an air jet is shown, wherein for simplicity, neither the turbine nor its housing is shown.

[0036] As described in the background section, the cooling device 100 includes at least one air outlet manifold 110 (also referred to as a cooling manifold) connected to at least one air distribution shroud 120. Figure 6 In the example shown, ten cooling manifolds 110 are illustrated, each connected to at least one air distribution shroud 120. Preferably, each manifold is connected to two air distribution shrouds 120, which are positioned approximately 180° apart from each other, as shown below. Figure 2 As shown. These two covers, even if not exactly the same, are similar.

[0037] Air distribution hood 120 (hereinafter referred to as the hood) includes an air inlet compartment connected to the outer pipe of the turbine (in Figure 6 (Invisible in the middle), air flows through the outer tube to allow cooling of the various components of the turbine, such as... Figure 2 As shown. The air inlet compartment delivers cooling air from the outer pipe to the interior of the air distribution hood 120 and then to the cooling manifold 110.

[0038] The air distribution hood 120 also includes a cover 124 that is tangentially closed by a first lateral wall 125 and a second lateral wall 126, which are referred to as opposing because they face each other. The first lateral wall 125 and the second lateral wall 126 form an angle between them, which has a vertex at the upstream end of the air distribution hood 120. In other words, the tangential distance between the first lateral wall 125 and the second lateral wall 126 increases from upstream to downstream. In other words, the cover 124 of the hood opens from upstream to downstream.

[0039] In order to secure the air distribution hood 120 to the housing, the hood 120 includes brackets 121 mounted on the housing 124. These brackets can be secured to the outer surface of the housing 124 of the air distribution hood 120 and to the housing by any known means (welding, gluing, etc.).

[0040] Each cooling manifold 110 includes two cooling pipes 112 disposed on both sides of the shroud 120 and extending more than approximately 180°. The cooling pipes 112 have a preferably circular cross-section and are curved to match the external shape of the housing 48. The cooling pipes 112 of each manifold extend parallel to each other along the semicircle of the housing. Each pipe 112 is penetrated by a series of small orifices that open in a straight line with the outer surface of the housing 48 to provide impingement ventilation of the housing. Pressurized air through these orifices provides impingement ventilation of the housing 48. Each pipe 112 is connected via a first end to a first lateral wall 125 of one air distribution shroud 120 and via a second end to a second lateral wall 126 of another air distribution shroud. Of course, if the cooling device 100 includes only one air distribution shroud 120, then the first end of the pipe 112 is connected to the first lateral wall 125 of the air distribution shroud 120, and the second end of the pipe 112 is connected to the second lateral wall 126 of the same air distribution shroud 120. Furthermore, if the cooling device 100 includes two or more air distribution shrouds 120, for example, n shrouds, then the n cooling pipes 112 will be connected between two air distribution shrouds in the n consecutive air distribution shrouds.

[0041] Therefore, in Figure 6 In the example shown, the first lateral wall 125 of the air distribution shroud 120 is adapted to receive each pipe 112 of the cooling manifold 110. Similarly, the second lateral wall 126 of the air distribution shroud 120 is adapted to receive each pipe 112 of the cooling manifold 110. For this purpose, as Figure 6 and Figure 7 As shown, each of the side walls 125, 126 includes as many air outlet orifices 127 or circular orifices as the pipes 112 of the cooling manifold 110. Each orifice 127 has a main axis P (e.g., Figure 7 (as shown), and is constructed and sized to accommodate an associated cooling pipe 112.

[0042] Additionally, one of the side walls 125 and 126 of the air distribution hood 120 is adapted to receive the air inlet compartment.

[0043] Additionally, the cooling device 100 includes a fastening system 140 configured to secure the cooling pipes to the housing. The fastening device 140 for securing the cooling manifold to the housing of the turbine (particularly a low-pressure turbine) is designed to prevent changes in the air gap between the manifold and the outer wall of the housing, even when hot (i.e., during turbine operation), and more specifically, to maintain a constant air gap between the air outlet orifice formed in the pipe and the outer surface of the housing, regardless of temperature, i.e., whether the turbine is stationary or in operation. For this purpose, the fastening system 140 includes at least one manifold support 141. Figure 8 A schematic diagram of such a manifold support is shown from below (i.e., from the inside to the outside in the radial direction). The support, or each support member, is configured to hold the manifolds spaced apart in the axial direction A of the housing 48. The manifold supports 141 are secured to the housing by flanges in a known manner. Each manifold support 141 includes at least one fastening clamp 142 for securing one of the cooling pipes 112. Each fastening clamp 142 is configured to hold the cooling pipe 112 in place on the manifold support 141.

[0044] According to the present invention, unlike the prior art, each cooling pipe 112 of the cooling manifold 110 is fixed to a fastening system, more specifically to a fastening clamp 142. Preferably, each cooling pipe 112 is securely fastened to the fastening clamp 142 by brazing, welding or gluing.

[0045] This type of fastening system ensures the mechanical strength of the cooling manifold while maintaining the manufacturing integrity of the cooling pipes. This fastening system also prevents wear between the cooling pipes 112 and the clamps in their contact area.

[0046] According to the invention, the tangential movement of the cooling pipes 112 is managed at the air distribution shroud 120. For this purpose, each cooling pipe 112 is movably connected relative to the distribution shroud 120. More specifically, each cooling pipe 112 can translate along the main axis P within the associated orifice 127 of the lateral walls 125, 126 of the shroud. Therefore, this configuration allows the cooling pipe 124 to slide at its connection point with the air distribution shroud 120.

[0047] Preferably, each tube 112 is connected to one of the circular openings 127 in the sidewall by means of a sliding cylindrical socket 150 provided in one of the air outlet openings 127. Each socket 50 is constructed and sized to receive an associated cooling tube. Thus, the socket 150 has a cross-section (preferably circular) that matches the cross-section of the associated cooling tube 112.

[0048] Each socket 150 is formed as a single component to the side wall, for example, by brazing or gluing. Each socket 150 includes a cylindrical body 152 having an inner cylindrical wall 154, the axis of which is the principal axis P of the associated air outlet orifice 127. Figure 7 In the example shown, the cylindrical body 152 is brazed to the side wall of the cover via a contact surface 153 between the two elements. Alternatively, the cylindrical body 152 has an outer cylindrical wall coaxial with the inner cylindrical wall 154, and the outer cylindrical wall of each socket 150 is brazed to one of the circular openings 127 in the side walls 125, 126 of the cover 120.

[0049] Advantageously, the inner cylindrical wall 154 includes an annular groove 156 that accommodates a sealing element 158, such as a seal to ensure a tight connection, preferably an O-ring. Additionally, the shroud lacks a stop at the end of the cooling pipe 112 located on the shroud 120 side, allowing for easy replacement of the gasket in case of wear.

[0050] Preferably, the inner cylindrical wall 154 further includes a coating for improving sliding, i.e., a coating coverage for improving sliding. Such a coating enables the improvement of the wear resistance of the inner cylindrical wall 154.

[0051] Advantageously, the coating used to improve slip is graphite, preferably deposited in a thin layer on the inner cylindrical wall 154. In other words, the inner cylindrical wall 154 is covered with a graphite layer. This deposit can be produced by chemical vapor deposition (CVD) or physical vapor deposition (PVD).

[0052] Although described in many examples, variations, and embodiments, the cooling device according to the invention includes various variations, modifications, and improvements that will be apparent to those skilled in the art, and it should be understood that such variations, modifications, and improvements are within the scope of the invention. For example, the cooling manifold may consist of a single annular pipe extending over a corner sector of approximately 360°, or of two or more parallel pipes forming a total corner sector of approximately 360° and connected to each other by an air distribution shroud.

Claims

1. An apparatus (100) for cooling a turbine housing (48), particularly a low-pressure turbine (28), using an air jet, the apparatus comprising at least one air supply shroud (120) and at least one cooling manifold (110) intended to be disposed around the housing to be cooled, the cooling manifold or each cooling manifold comprising two cooling tubes (112) disposed on both sides of the shroud, the supply shroud (120) comprising two side walls (125, 126), each side wall comprising an air outlet orifice (127), each orifice having a main axis and configured and sized to receive an associated cooling tube among the cooling tubes, the cooling apparatus comprising a fastening system intended to secure the cooling tubes to the housing, each side wall (125, 126) of the supply shroud comprising at least one sliding port (150) disposed in one of the air outlet orifices, each sliding port (150) configured and sized to receive an associated cooling tube among the cooling tubes (112), characterized in that, Each cooling tube is secured to the fastening system and is translatable along the main axis (P) in the associated orifice, and each of the at least one sliding sockets (150) includes an inner cylindrical wall (154) whose axis is the main axis of the associated air outlet orifice (127), and the inner cylindrical wall includes an annular groove (156) for receiving a sealing element (158).

2. The apparatus according to claim 1, wherein, The sealing element (158) is a gasket, preferably an O-ring.

3. The apparatus according to claim 1 or 2, wherein, Each sliding socket forms a single component with the side wall.

4. The apparatus according to any one of the preceding claims, wherein, The fastening system includes at least two supports (141) for fastening the at least one manifold to the housing, each manifold support (141) including at least one fastening clamp (142) for fastening one of the pipes of the same manifold to the fastening clamp, for example by brazing, welding or gluing.

5. The apparatus of claim 4, comprising at least two cooling manifolds, wherein, Each support of the fastening system is shaped to keep the manifolds spaced apart.

6. The apparatus according to any one of the preceding claims, wherein, Each cooling tube (112) is curved and designed to be positioned around a portion of the housing to be cooled and at a distance from said portion of the housing, and each cooling tube includes a plurality of orifices leading to said housing.

7. The apparatus according to any one of the preceding claims, wherein, The inner cylindrical wall (154) includes a coating to improve sliding.

8. The apparatus according to any one of the preceding claims, wherein, The inner cylindrical wall (154) is covered with a graphite layer.

9. A turbine, particularly a low-pressure turbine, the turbine comprising a housing and equipped with a cooling device (100) using an air jet according to any one of the preceding claims.

10. A turbine, particularly an aircraft turbine, comprising a turbine according to claim 9, particularly a low-pressure turbine, or comprising a housing and equipped with a cooling device (100) using an air jet according to any one of claims 1 to 8.

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