Turbo housing cooling device

Abstract

The present invention relates to a casing (130) for a turbine (1) of a turbine engine, the casing (130) extending around an axis (X) and including an annular wall (112) and cooling means (100), the wall (112) being provided with at least one casing hook (120), at least one casing hook protruding radially outwards on the inner side of the wall (112), each hook (120) being configured to mount on the casing (30) a plurality of ring segments arranged end-to-end circumferentially around the axis (X), wherein the cooling means (100) includes at least one collecting channel (110) for conveying cooling air and extending circumferentially around the wall (112), each collecting channel (110) having a cooling air inlet and a cooling air outlet, characterized in that each collecting channel (110) and the wall (112) have a common portion (150), the common portion defining the collecting channel (110) and the corresponding hook (120) extending from the common portion.

Description

Technical field

[0001] The present invention relates to a turbine housing of a turbine, in particular a turbine housing of a turbojet engine or an aircraft turboprop engine. Background art

[0002] The housing of a low-pressure turbine is a main component for carrying the low-pressure turbine and ensuring the correct transfer of expansion energy to the low-pressure turbine, the low-pressure compressor and the fan. The housing mainly uses housing hooks to support the ring segments, and the ring segments guide the fan blades around each wheel and nozzle. These hooks are subjected to high temperatures and steep temperature gradients. Specifically, outside the housing, the temperature level of the air is about several hundred degrees Celsius, while the flow channel air with a temperature of up to more than 1000 °C circulates inside the housing. Therefore, it is beneficial to cool the housing hooks.

[0003] In addition, in order to ensure the high efficiency of the turbine, it is recommended to limit the air flow that does not flow through the wheels of different stages, that is, to limit the leakage between the radially outer ends of the blades and the wear-resistant material ring. For this purpose, it is recommended to control the clearance at this interface position, which depends on the temperature of the housing, especially the temperature of the area of the housing including the hooks or flanges of the support ring.

[0004] In order to control the above-mentioned clearance and avoid any premature deterioration of different fixed and movable components of the turbine, it is therefore necessary to provide effective cooling devices that can be easily incorporated into the environment of the turbine.

[0005] Att Figure 1 Fig. shows a housing cooling device according to the patent application FR3021700 signed by the applicant. The figure shows the cooling device 21 of the housing 18 of the low-pressure turbine 7, and the turbine 7 itself is only visible in Figure 3 and Figure 4 The cooling device includes a collector box 22, and each collector box 22 forms an axially extending channel. The device 21 also includes tubes 23 that circumferentially extend on both sides of the collector box 22. The tubes 23 are also called manifolds and are formed by curved pipelines with a circular cross-section. Each tube 23 circumferentially extends around the housing, for example, extends around an angle of about 90 degrees. Each tube 23 includes an air inlet and a closed distal end. The air inlet opens into the channel of the corresponding collector box 22. Each tube 23 also includes a cylindrical wall, and the cylindrical wall is provided with air discharge holes facing the housing 18, so that the cooling air can enter the collector box 22, then enter the tube 23, and then be opened through the discharge holes facing the housing 18 to cool the housing. This is particularly called impingement cooling because the air impinges on the housing 18.

[0006] In addition, although in Figure 1It is not visible in the [description], but the housing 18 includes at least one annular hook on its radial inner surface, which enables the installation of a fixed blade or a seal ring segment. However, it is not possible to properly cool these hooks with the aforementioned air jet impingement cooling technique. Therefore, it is desirable to improve the cooling of the housing skin so as to improve the cooling of the hooks over their entire length, thereby improving the thermal resistance at the hook ends.

[0007] Document EP1847687 is also known, which provides a device for cooling the turbine housing of a turbine. Attached Figure 2 , 2a Figures 2a,

[0008] 2b show such a cooling device. The cooling device uses a part of the air intended to cool the nozzle guide vanes upstream of the turbine to cool the hooks 70, 72 and the locking part 74 (the hooks 70, 72 and the locking part 74 enable the attachment of the ring segment 34). Thus, in this document, the supply chamber 48 uses a cylindrical tube 54 to supply air to the inner cavity 46 of the vanes of the nozzle guide vanes. Openings 80, 82, 90 are made to connect the inner cavity 46 of the vanes to the annular accommodation space 76, in which the attachment hooks 70, 72 are located. More precisely, the openings are made in Figure 2 and Figure 2a - the plate 64 surrounding the inner cavity of each vane and in the downstream outer edge 42 of the outer wall 38 of the nozzle guide vane, as

[0009] shown in Figures 2a Figure 2b and 2b; or

[0010] - the annular outer edge 42 of the nozzle guide vane and in the annular tab 44 of this outer edge 42 of the nozzle guide vane, as Figure 2b shown in Figure 2c.

[0010] However, in both cases, due to the convective exchange with the radial outer platform 38 of the nozzle guide vane, the air used to cool the hooks is relatively hot. In addition, the ducts for delivering the cooling air from the inside of the vanes to the hooks are relatively long, which means that the air undergoes additional heat exchange in these ducts.

[0011] Finally, from documents EP 0892153, GB 2103718, EP 1205637 and US2014 / 030066, devices for cooling a housing are known, the housing being equipped with ring segment attachment hooks on its radial inner surface. However, all these devices include a collector duct intended to convey the cooling air, which is separated from the housing carrying the hooks. The cooling is achieved through air discharge holes that penetrate the collector duct and are directed along the direction of the housing. Such impingement cooling is not sufficient to effectively cool the hooks.

[0012] Therefore, it is necessary to improve the cooling techniques in the prior art. SUMMARY OF THE INVENTION

[0013] An object of the present invention is to provide better cooling of the turbine housing hooks than the solutions of the prior art described above.

[0014] Thus, according to a first aspect of the present invention, there is provided a turbine housing, the housing extending around an axis, including an annular wall and cooling means, the wall being provided with at least one housing hook, at least one housing hook extending radially inwardly from the inner side of the wall, each hook being configured to allow the mounting on the housing of a plurality of ring segments arranged end-to-end circumferentially around the axis, wherein the cooling means includes at least one collector duct, at least one collector duct being intended to convey cooling air and extending circumferentially around the wall, each collector duct having a cooling air inlet and a cooling air outlet.

[0015] According to the present invention, each collector duct and the wall have a common portion, the common portion defining the collector duct and the corresponding hook extending from the common portion.

[0016] In other words, the wall from which the hook extends forms part of the wall of the collector duct intended to convey cooling air.

[0017] This configuration enables a larger portion of the outer surface of the housing to be cooled than can be cooled using prior art devices, thereby increasing the life of the housing.

[0018] Advantageously, the turbine housing further includes one or more of the following features:

[0019] - The cooling means includes two axially adjacent collector ducts separated by a partition wall.

[0020] - Each collector duct is in fluid communication with a ventilation circuit extending in the corresponding hook.

[0021] - Each ventilation circuit extends in a larger axial portion of the axial extent of the corresponding hook.

[0022] - Each ventilation circuit extends circumferentially in the corresponding hook.

[0023] - The inlet of each collector duct is connected to a supply pipe for delivering air into the collector duct.

[0024] - Each ventilation circuit opens radially into the corresponding collector duct mainly through an inlet passage.

[0025] - Each ventilation circuit opens to the outer surface of the cooling means through an outlet passage.

[0026] - The inlet passage and / or the outlet passage extends perpendicular to the corresponding hook.

[0027] - The inlet and outlet channels extend at a first circumferential position and a second circumferential position of corresponding hooks, the first circumferential position and the second circumferential position of the corresponding hooks being intended to coincide with circumferentially opposite ends of an annular section intended to be suspended on the corresponding hooks.

[0028] The proposed cooling device enables better cooling of the casing hooks over the entire length of the casing hooks, increasing the life of the hooks by limiting the thermal gradient along the length of the hooks and by limiting the tangential thermal gradient.

[0029] Furthermore, the circulation of air over the circumferentially extending section enables better cooling of the hook ends and reduces angular thermal deformation.

[0030] Furthermore, the casing collector system enables the inlet cooling temperature of the casing to be equalized.

[0031] Furthermore, compared with the prior art, the proposed cooling device enables a lower exhaust gas flow rate to be extracted to provide the same casing thermal protection function.

[0032] Furthermore, the proposed cooling device can be easily incorporated into an engine model consisting of a casing with hooks.

[0033] According to a second aspect, the present invention provides a turbine, the turbine comprising a turbine and a turbine casing according to one of the above characteristics. Description of the Drawings

[0034] Other features, objects and advantages of the present invention will become apparent from the following description, which is illustrative only and non-limiting and must be read with reference to the accompanying drawings, in which:

[0035] The above-described Figure 1 is a perspective view of a prior art cooling device;

[0036] The above-described Figure 2 is a cross-sectional view of a prior art cooling device;

[0037] The above-described Figure 2a is Figure 2 an enlarged cross-sectional view of the device;

[0038] The above-described Figure 2b is an enlarged cross-sectional view of another prior art cooling device;

[0039] Figure 3 is an axial cross-sectional view of a prior art twin-spool turbojet engine;

[0040] Figure 4 is an axial cross-sectional view of a part of a prior art turbojet engine, specifically showing the low-pressure turbine;

[0041] Figure 5 is a perspective view of a turbine housing cooling device according to an embodiment of the present invention; and

[0042] Figure 6 is Figure 5 a detail view of the turbine housing cooling device of Detailed Description

[0043] Figure 3 shows a twin-spool, dual-path turbine 1. The axis of the turbine is indicated by reference numeral X and corresponds to the axis of rotation of the rotating components. Hereinafter, the terms "axial" and "radial" are defined with respect to the axis X.

[0044] The turbine 1 includes, from upstream to downstream along the gas flow direction, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, and a low-pressure turbine 7.

[0045] The air from the fan 2 is divided into a main stream 8 and a secondary stream 10. The main stream 8 flows in a main annular flow path 9, and the secondary stream 10 flows through a secondary annular flow path 11 surrounding the first annular flow path 9. The low-pressure compressor 3, the high-pressure compressor 4, the combustion chamber 5, the high-pressure turbine 6, and the low-pressure turbine 7 are formed in the main flow path 9.

[0046] The rotor of the high-pressure turbine 6 and the rotor of the high-pressure compressor 4 are rotationally coupled by a first shaft 12 to form a high-pressure spool.

[0047] The rotor of the low-pressure turbine 7 and the rotor of the low-pressure compressor 3 are rotationally coupled by a second shaft 13 to form a low-pressure spool. The fan 2 can be directly connected to the rotor of the low-pressure compressor 3 or, for example, connected to the rotor of the low-pressure compressor 3 through an epicyclic gear train.

[0048] As can be seen more clearly in Figure 4 the low-pressure turbine 7 particularly includes different successive stages, which include wheels 14 and stationary components. The wheel includes a disk 15, and blades 16 are mounted at the position of the disk 15. The ends of the blades 16 are surrounded by a stationary ring 17 made of a wear-resistant material, and the ring 17 is attached to the housing 18 of the turbine. Nozzle guide vanes 19 are located upstream of the wheel 14. The nozzle guide vanes 19 and the ring 17 are mounted on the housing by flanges or hooks 20 that extend from the radially inner surface of the housing 18. The housing 18 mainly supports the ring segments that surround each wheel 14 and the nozzle guide vanes 19 using circumferential hooks 20 attached to the housing.

[0049] Referring to Figure 5 and Figure 6 shows a cooling device 100 for a turbine housing 130 (e.g., for the low-pressure turbine of the turbine 1) according to an embodiment of the present invention.

[0050] The cooling device 100 is incorporated into the housing 130.

[0051] The housing 130 extends around the longitudinal axis X of the turbine, which is also the longitudinal axis of the turbine.

[0052] The housing 130 includes an outer surface 131 and an inner surface 132 on the radial wall.

[0053] The housing 130 also includes a plurality of hooks 120 that project radially inward relative to its inner surface 132. As previously described, the hooks 120 enable the attachment of the vanes of the stator blades (nozzle guide vanes) of the low-pressure turbine to the seal ring section, which includes a wearable element that is intended to be arranged to face the blades of the rotor radially.

[0054] Advantageously, the hooks 120 extend continuously in the circumferential direction of the inner surface 132, such that an annular manifold is formed at a plurality of positions axially offset relative to the housing 130.

[0055] It is necessary to protect the housing 130 from overheating to maintain the integrity of the components of the housing 130, and it also serves another purpose, namely, to control the radial clearance between the blades of the turbine and the housing 130 surrounding the blades. Specifically, due to the thermal expansion of the housing 130, the temperature change of the housing 130 causes the clearance between the blades and the housing to change.

[0056] The reduction of the clearance between the tip of the blade and the housing 130 is a decisive factor in the performance of the turbine, because the smaller the radial clearance, the smaller the flow rate bypassing the blade, and the higher the efficiency of the turbine.

[0057] Therefore, controlling the clearance can avoid turbine performance losses. In an engine, it is crucial to control the clearance between the tip of the blade and the outer peripheral casing. The radial displacement of this annular casing depends on the expansion of the housing 130, so it is necessary to use fresh air to control the temperature of at least a part of the housing 130.

[0058] Since these hooks 120 are the parts of the housing 130 that directly determine the clearance at the blade ends, it is very useful for the cooling device 100 to provide components for cooling these hooks 120.

[0059] For this purpose, the device 100 includes a plurality of collector pipes 110, and the plurality of collector pipes 100 extend circumferentially around the housing 130 substantially entirely on the outer circumference (i.e., substantially at 360°). Figure 5 and Figure 6 In the exemplary embodiment shown, the number of these collector pipes 110 is two.

[0060] Each collector duct 110 surrounds the housing 130 on a respective circumferential portion of the housing. As shown, hooks 120 are provided circumferentially on the inner surface 132 of the housing 130 across a plurality of axially spaced stages. Advantageously, each collector 110 is arranged to extend on a circumferential segment of the stage including the hook 120.

[0061] Typically, for a low-pressure turbine, the cooling device 100 includes a plurality of collector ducts 110 provided on as many stages of the hooks 120 of the housing 130 as possible.

[0062] Each collector duct 110 is connected to a supply duct 140. The supply duct 140 is mainly radial and opens onto the outer surface of the cooling device 100. The supply duct 140 is configured to draw cold air from a discharge point; the discharge point is typically a point on a secondary flow path of the gas from the machine, and a portion of the air flow at this point is drawn out in a manner known in the prior art. Accordingly, each collector duct 110 is connected to a pressurized air supply source for delivering air into the duct 110.

[0063] In the illustrated embodiment, the collector duct 110 includes an outer wall 111 (radially on the outside) and an inner wall 112 (radially on the inside), and two side walls 113 provided on both sides of the outer wall 111 and the inner wall 112. Two axially adjacent collector ducts 110 may be separated by a partition wall formed by one of the side walls 113 common to the two adjacent collector ducts 110.

[0064] The outer wall 111 includes holes for connecting the collector duct 110 to the supply duct 140. The connection to the pressurized air supply source may be formed on any wall of the collector 110 other than the inner wall 112.

[0065] The outer wall 111 and the inner wall 112 are concentric, and the collector duct 110 can have a trapezoidal cross-section.

[0066] Advantageously, the inner wall 112 is configured to conform to the shape of the circumferential segment of the housing 130 such that the inner wall 112 forms part of the outer surface (skin) of the housing 130. In other words, each collector duct 110 and the wall 112 equipped with at least one hook 120 have a common portion 150, as can be seen in Figure 5 This configuration enables a larger portion of the outer surface of the housing 130 to be cooled than can be cooled using prior art devices, thereby increasing the lifespan of the housing 130.

[0067] Advantageously, the collector duct 110 is made of a single piece and can be obtained by an additive manufacturing process such as laser melting.

[0068] As Figure 6As shown in more detail, and different from the prior art, at least one hook 120 is not a solid section, but includes at least one ventilation circuit 121, which includes an inlet channel 122, an outlet channel 124, and an internal longitudinal channel 123. The internal longitudinal channel 123 extends between the inlet channel 122 and the outlet channel 124 over the circumferential length of the hook 120.

[0069] The inlet channel 122 is used to connect the longitudinal channel 123 to the interior of the collector duct 110. Preferably, the inlet channel 122 is perpendicular to the hook 120.

[0070] Through a passage 115 that passes through the collector duct 110 and opens to the surface of the outer wall 111, the outlet channel 124 enables the connection of the longitudinal channel 123 to the exterior of the housing 130 and the exterior of the collector duct 110. Preferably, the outlet channel 124 is perpendicular to the hook 120.

[0071] Advantageously, the outlet channel 124 is used to connect the longitudinal channel 123 to a point on the turbine 1 where the pressure is lower than the pressure at the discharge point. Preferably, the discharge point is located in the core.

[0072] As previously described, the hook 120 is configured to support a ring section. Preferably, for each ring section, the hook 120 includes an inlet channel 122 and an outlet channel 124. Advantageously, the inlet channel 122 and the outlet channel 124 are provided at a first circumferential position and a second circumferential position of the hook 120, and the first circumferential position and the second circumferential position correspond to the circumferentially opposite ends of the ring section positioned in the hook 120. Thus, the circumferential length of the longitudinal channel 123 is approximately equivalent to the circumferential length of a ring section.

[0073] Generally, for a low-pressure turbine, the housing 130 hooks 120 are configured to support 20 to 30 ring sections. Thus, for one circumferential section of the housing 130 including one stage of hooks 120, the cooling device 100 will include a corresponding number of ventilation circuits 121, that is, 20 to 30 ventilation circuits following one another circumferentially.

[0074] Preferably, within the same hook 120, for two consecutive ventilation circuits 121, the outlet channel 124 of the first ventilation circuit 121 is connected to the inlet channel 122 of the second ventilation circuit 121.

[0075] Advantageously, different from the prior art of cooling the hook by an impingement jet device, the cooling device 100 enables the use of a pressurized air source and the circulation of pressurized air within the housing 130 hooks 120, thereby increasing the cooling capacity by pumping the cooling air.

[0076] In addition, the circulation of air over the circumferentially extending section enables better cooling of the hook ends and reduces angular thermal deformation.

[0077] Thus, the cooling device 100 enables better cooling of the housing 130 hooks 120 over the entire length of the housing 130 hooks 120, increasing the life of the hooks by limiting the thermal gradient along the length of the hooks 120 and by limiting the tangential thermal gradient.

[0078] In addition, the collector pipe 110 system of the housing 130 can equalize the cooling inlet temperature of the housing 130.

[0079] In addition, compared with the prior art, the cooling device 100 enables a lower exhaust gas flow rate to be drawn to perform the same housing thermal protection function.

[0080] In addition, the cooling device 100 can be easily incorporated into an engine model including a housing with hooks.

[0081] Naturally, the present invention is not limited to the embodiments described with reference to the drawings, and different variations can be envisioned without departing from the scope of the present invention. Thus, the collector pipe can have other geometries.

Claims

1. A turbine housing (130) of a turbine (1), the turbine housing (130) extending around an axis (X), comprising an annular wall (112) and a cooling device (100), the wall (112) being provided with at least one housing hook (120), the at least one housing hook extending radially protruding from the inner side of the wall (112), each of the hooks (120) being configured to allow a plurality of ring segments arranged end to end in a circumferential direction around the axis (X) to be mounted on the turbine housing (130), wherein: The cooling device (100) includes at least one collector duct (110) which is intended to convey cooling air and extends circumferentially around the wall (112). Each collector duct (110) has a cooling air inlet and a cooling air outlet. It is characterized in that each collector duct (110) and the wall (112) have a common portion (150) which defines the collector duct (110) and corresponding hooks (120) extend from the common portion.

2. The turbine housing (130) of the turbine (1) according to claim 1, wherein, The cooling device (100) includes two axially adjacent collector ducts (110) which are separated by a partition wall (113).

3. Turbine housing (130) of a turbine (1) according to any one of the preceding claims, wherein, Each collector duct (110) is in fluid communication with a ventilation circuit (121) which extends in the corresponding hook (120).

4. Turbine housing (130) of the turbine (1) according to claim 3, wherein, The ventilation circuit (121) extends in a greater axial portion of the axial extent of the corresponding hook (120).

5. The turbine housing (130) of the turbine (1) according to claim 3, wherein, The ventilation circuit (121) extends circumferentially in the corresponding hook (120).

6. The turbine housing (130) of the turbine (1) according to claim 5, wherein, The inlet of each collector duct (110) is connected to a supply pipe (140) which is used to convey air into the collector duct (110).

7. The turbine housing (130) of the turbine (1) according to claim 3, wherein, The ventilation circuit (121) opens radially into the corresponding collector duct (110) through an inlet passage (122).

8. The turbine housing (130) of the turbine (1) according to claim 3, wherein, The ventilation circuit (121) opens to the outer surface of the cooling device (100) through an outlet passage (124).

9. Turbine housing (130) of the turbine (1) according to claim 7, wherein, The inlet passage (122) extends perpendicular to the corresponding hook (120).

10. The turbine housing (130) of the turbine (1) according to claim 8, wherein, The outlet passage (124) extends perpendicular to the corresponding hook (120).

11. The turbine housing (130) of the turbine (1) according to claim 7, wherein, The ventilation circuit (121) opens to the outer surface of the cooling device (100) through an outlet passage (124), and wherein the inlet passage (122) and the outlet passage (124) extend at a first circumferential position and a second circumferential position of the corresponding hook (120), and the first circumferential position and the second circumferential position of the corresponding hook (120) are intended to coincide with the circumferentially opposite ends of an annular segment intended to be mounted on the corresponding hook (120).

12. A turbine (1), comprising a turbine, characterized in that, The turbine includes a turbine housing (130) according to any one of the preceding claims.

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