Scoop exhaust case arm with flow Anti-reversal device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-05
- Publication Date
- 2026-08-13
Smart Images
Figure FR2026050112_13082026_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] Title of the invention: Exhaust crankcase arm with anti-reversal device
[0003] TECHNICAL FIELD
[0004] The present invention relates to the field of aircraft turbomachinery, and more specifically to exhaust housings.
[0005] It relates more specifically to reducing fuel consumption and improving the lifespan of equipment.
[0006] The invention applies to all turbomachine designs, an aeronautical turbine for an airplane or helicopter engine.
[0007] PREVIOUS TECHNIQUE
[0008] In a turbomachine, here a turbojet engine labeled 1 in Figure 1, air is admitted into an inlet sleeve 2 to pass through a fan comprising a series of rotating blades 3 before splitting into a central primary flow which circulates in a so-called primary airflow duct Fi and a secondary flow FH surrounding the primary flow Fi. The primary flow Fi and the secondary flow FH are separated by an intermediate casing 12.
[0009] The primary flow Fi is compressed by compressor stages 4 and 5 before reaching a combustion chamber 6, after which it expands as it passes through turbines 7, before being expelled through an exhaust casing 8, generating thrust. The secondary flow FH, on the other hand, is propelled directly by the fan to generate the main thrust.
[0010] The compressor stages include distributors regularly spaced around a shaft 9 mounted for rotation about an axis AX in a frame 10 – also called a nacelle – surrounding the assembly and to which the various components of the turbojet 1 are connected. The shaft 9 extends into a central casing 11. The exhaust casing 8 is conventionally cylindrical with its axis of revolution substantially parallel to the axis Ax to define an exhaust volume Ve. It is generally made of stainless steel or nickel, or of heat-resistant alloys such as Inconel, capable of withstanding the extreme temperatures generated by the exhaust gases.
[0011] The exhaust casing 8 is generally supported by several radially extending exhaust casing arms 20 which connect the frame 10 to the shaft support bearings 13 9. These exhaust casing arms 20 then extend into the exhaust flow Fe exiting the turbines 7.
[0012] In specific applications such as afterburning engines and / or applications where the number of turbine stages 7 is reduced, the exhaust casing arms 20 must withstand extremely high temperatures, sometimes exceeding six hundred degrees. The exhaust casing arms 20 are therefore generally made of expensive materials and are subjected to regular monitoring to ensure their resistance to the thermal cycles and mechanical stresses to which they are subjected.
[0013] It is known to reintroduce a portion of the air from the secondary flow into the primary flow. This practice aims to improve the overall thermal efficiency of the turbomachine. By reintroducing cooler air from the secondary flow, better control of exhaust gas temperatures is achieved, thus optimizing the thermodynamic cycle of these machines.
[0014] One of the major advantages of this air reintroduction is the significant reduction in nitrogen oxide (NOx) emissions, thanks to a more efficient and better-controlled combustion process. By limiting thermal variations and maintaining more consistent temperatures, the reliability and durability of critical engine components are improved, thus reducing thermal fatigue and associated maintenance costs.
[0015] An additional advantage arises in turbomachinery equipped with an afterburner, where the primary and secondary flows converge at the afterburner system. By promoting better air distribution upstream of the secondary combustion zone, this air reintroduction enriches the primary air with oxygen before it passes through the flame-gripping arms, thus improving the energy efficiency of the afterburner. Furthermore, optimizing the mixing of the primary and secondary flows results in more homogeneous pressure, temperature, and velocity profiles at the exhaust, contributing to increased thrust and improved turbomachine performance control.
[0016] Conventionally, systems of ducts and valves are used to draw air from the secondary flow and redistribute it to specific sections of the engine, such as the combustion chamber. The invention aims to improve the environmental performance of a turbomachine, particularly by improving the durability and operating costs of an exhaust housing arm.
[0017] DESCRIPTION OF THE INVENTION
[0018] To this end, the invention provides a turbomachine comprising a cylindrical exhaust housing with an axis extending along an axial direction and defining an exhaust volume through which an exhaust flow passes. The exhaust housing is connected to a turbomachine frame by an exhaust housing arm extending essentially radially along a principal axis. This arm includes a casing that delimits an internal volume of the exhaust housing arm, the casing including an outlet port establishing fluid communication between the internal volume of the exhaust housing arm and the exhaust volume. The arm also includes an intake port for a cooling airflow into the internal volume.
[0019] According to the invention, the exhaust crankcase arm also includes a passive flow management device, arranged to allow the flow of cooling air from the intake port to the outlet port. This flow management device is also arranged to prevent reverse flow from the outlet port to the intake port.
[0020] According to other particular, non-exclusive and optional embodiments of the invention: • A first distance measured along the axial direction and separating the flow management device from the inlet port is less than a second distance measured along the axial direction and separating the flow management device from the outlet port.
[0021] • The exhaust housing arm includes an internal mast around which the bodywork extends.
[0022] • The flow management device includes a first profile extending into the internal volume in a direction substantially parallel to the main axis.
[0023] • The first profile has a curved cross-section which defines a first portion located in a first stagnation zone of the first profile when it is subjected to the cooling airflow and a second portion located in a first wake zone of the first profile when it is subjected to the cooling airflow.
[0024] • The first portion of the first profile is convex.
[0025] • The second portion of the first profile is concave.
[0026] • The flow management device comprises a plurality of profiles extending into the internal volume in a direction substantially parallel to the main axis and positioned in a staggered pattern.
[0027] • The first profile is connected to the internal mast or the casing.
[0028] • The flow management device includes a second profile having a cross section which defines a third flat portion extending at least partially into the first wake zone and a fourth curved portion located in a second wake zone.
[0029] Other features and advantages of the invention will become apparent from the following description of a particular, non-limiting embodiment of the invention.
[0030] BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Reference will be made to the attached figures, among which: [Fig. 1] Figure 1 is a schematic axial cross-sectional representation of a turbomachine;
[0032] [Fig. 2] Figure 2 is a schematic partial perspective representation of a turbomachine equipped with an exhaust casing arm according to a first embodiment of the invention;
[0033] [Fig. 3] Figure 3 is a schematic orthoradial cross-sectional representation of an exhaust crankcase arm according to the first embodiment of the invention subjected to a cooling flow;
[0034] [Fig. 4] Figure 4 is a partial schematic detail representation of the exhaust crankcase arm of Figure 3;
[0035] [Fig. 5] Figure 5 is a partial schematic detail representation in orthoradial section of a straight portion of the exhaust crankcase arm of Figure 3;
[0036] [Fig. 6] Figure 6 is a partial schematic detail representation in orthoradial section of a left portion of the exhaust crankcase arm of Figure 3;
[0037] [Fig. 7] Figure 7 is a schematic orthoradial cross-sectional representation of the exhaust crankcase arm according to the first embodiment of the invention subjected to a reverse flow
[0038] [Fig. 8] Figure 8 is a partial schematic detail representation in orthoradial section of the exhaust crankcase arm of Figure 7;
[0039] [Fig. 9] Figure 9 is a schematic orthoradial cross-sectional representation of an exhaust crankcase arm according to a second embodiment of the invention subjected to a cooling flow;
[0040] [Fig. 10] Figure 10 is a partial schematic detail representation of the exhaust crankcase arm of Figure 9;
[0041] [Fig. 11] Figure 11 is a partial schematic detail representation in orthoradial section of a straight portion of the exhaust crankcase arm of Figure 9;
[0042] [Fig. 12] Figure 7 is a partial schematic detail of the exhaust crankcase arm of Figure 9 subjected to a reverse flow. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0043] As a preliminary matter, an axial direction X is defined, a radial direction R which is orthogonal to the axial direction and a circumferential / tangential direction T which is orthogonal to the axial direction X and radial direction R.
[0044] In this text, the terms "inside" and "outside" are used with reference to the position or orientation relative to the axis of rotation Ax of the turbomachine 1. The terms "upstream" and "downstream" are used with reference to the position or orientation of an element relative to the direction of airflow in the turbojet.
[0045] The turbomachine 1 comprises several identical exhaust casing arms 20, of which only one exhaust casing arm 20 will be described below.
[0046] Referring to Figures 1 to 8, the crankcase arm 20 comprises an internal mast 21 and a casing 22 defining an internal volume V20 of the crankcase arm 20. The mast 21 and the casing 22 extend essentially radially along a principal axis A20 between an inner platform 23 and an outer platform 24. The mast 21 is designed to withstand the mechanical loads supporting the exhaust crankcase 8, and the casing 22 provides thermal protection for the mast 21 from the exhaust flow Fe. The mast 21 includes a central radial row 25 of perforations 26 connecting an internal volume V21 of the mast 21 to the volume V20 of the arm 20. The volume V21 is fluidically connected to an air source—here, a scoop (not shown) drawing air from the secondary flow Fn—which delivers a cooling airflow FR into the internal volume.
[0047] The housing 22 of the arm 20 comprises a leading edge element 30 and a trailing edge element 40 located downstream of the leading edge element 30. The leading edge element 30 and the trailing edge element 40 are connected by a right wall 50 and a left wall 60. The housing 22 has, here, a plane of symmetry P22 which includes the principal axis A20 and also the axial direction X.
[0048] The right wall 50 comprises a right radial row 51 of right circular injection orifices 52 which connect the internal volume V20 and the exhaust volume Ve. Similarly, the left wall 60 comprises a left radial row 61 of left circular injection orifices 62 which connect the internal volume V20 and the exhaust volume Ve.
[0049] As particularly visible in Figure 4, the exhaust housing arm 20 includes a flow management device 70 extending within the volume V20 between the central radial row 25 and the right radial rows 51 and left radial rows 61. The device 70 comprises ten disjoint profiles 71.1 to 71.10 extending within the internal volume V20 in a direction D71 substantially parallel to the main axis A20 along the entire height (considered along the main axis A20) of the arm 20 and positioned in a staggered pattern. More specifically, the device 70 includes a first right-hand device 72 grouping profiles 71.1 to 71.5 and a second left-hand device 73 grouping profiles 71.6 to 71.10. The device 72 is positioned between the central radial row 25 and the right radial row 51 so as to intercept the right fraction of cooling flow FR -designated FRD- which flows between the central radial row 25 and the right radial row 51.Symmetrically, the device 73 is positioned between the central radial row 25 and the left radial row 61 so as to intercept the left fraction of cooling flow FR -designated FRG- which flows between the central radial row 25 and the left radial row 61.
[0050] The device 72 comprises three central profiles: a first central profile 71.1, a second central profile 71.2, and a third central profile 71.3. The central profiles are bordered by a fourth right-hand profile 71.4 and a fifth left-hand profile 71.5. Profile 71.4 is connected to the right-hand wall 50 of the casing 22, and profile 71.5 is connected to the internal mast 21. Profiles 71.1, 71.2, 71.3, 71.4, and 71.5 are arranged in a staggered pattern in two rows. The first row comprises profiles 71.1 and 71.2, and the second row comprises profiles 71.3, 71.4, and 71.5. Profile 71.3 is installed between profiles 71.1 and 71.2, downstream of them in the direction of the straight cooling flow FRD. Profiles 71.4 and 71.5 are located outside profiles 71.1 and 71.2 and downstream of them in the direction of the straight cooling flow FRD.
[0051] The first profile 71.1 has a first curved cross-section T71.1 (considered in a plane P orthogonal to the direction D71) which defines a first convex portion 71.100 of the first profile 71.1 located in a first destagnation zone 81 of the first profile 71.1 when the first profile 71.1 is subjected to the straight fraction FRD of the cooling flux FR. The first cross-section T71.1 also has a second concave portion 71.11 of the first profile 71.1 located in a first wake zone 82 of the first profile 71.1 when the first profile 71.1 is subjected to the straight fraction F RD of FR cooling flow.
[0052] Similarly, the second profile 71.2 has a second curved cross-section T71.2 that defines a third convex portion 71.20 of the second profile 71.2 located in a second stagnation zone 83 of the second profile 71.2 when the second profile 71.2 is subjected to the straight fraction FRD of the cooling flux FR. The second cross-section T71.2 also has a fourth concave portion 71.21 of the second profile 71.2 located in a second wake zone 84 of the second profile 71.2 when the second profile 71.2 is subjected to the straight fraction FRD of the cooling flux FR.
[0053] The third profile 71.3 has a third curved cross-section T71.3 that defines a fifth convex portion 71.30 of the third profile 71.3 located in a third stagnation zone 85 of the third profile 71.3 when the third profile 71.3 is subjected to the straight fraction FRD of the cooling flux FR. The third cross-section T71.3 also has a sixth concave portion 71.31 of the third profile 71.3 located in a third wake zone 86 of the third profile 71.3 when the third profile 71.3 is subjected to the straight fraction FRD of the cooling flux FR.
[0054] Symmetrically, the device 73 comprises three central profiles: a sixth central profile 71.6, a seventh central profile 71.7, and an eighth central profile 71.8. The central profiles are bordered by a ninth left-hand profile 71.9 and a tenth right-hand profile 71.10. Profile 71.9 is connected to the left-hand wall 60 of the casing 22, and profile 71.10 is connected to the internal mast 21. Profiles 71.6, 71.7, 71.8, 71.9, and 71.10 are arranged in a staggered pattern in two rows. A third row comprises profiles 71.6 and 71.7, and a fourth row comprises profiles 71.8, 71.9, and 71.10. Profile 71.8 is positioned between profiles 71.6 and 71.7, downstream of them in the direction of the left-hand cooling flow FRG. Profiles 71.9 and 71.10 are located outside profiles 71.6 and 71.7 and downstream of them in the direction of the left-hand cooling flow FRG.
[0055] The sixth profile 71.6 has a sixth curved cross-section T71.6 (considered in plane P) which defines a sixth convex portion 71.60 of the sixth profile 71.6 located in a fourth stagnation zone 87 of the sixth profile 71.6 when the sixth profile 71.6 is subjected to the left fraction FRG of the cooling flux FR. The sixth cross-section T71.6 also has a seventh concave portion 71.61 of the sixth profile 71.6 located in a fourth wake zone 88 of the sixth profile 71.6 when the sixth profile 71.6 is subjected to the left fraction FRG of the cooling flux FR.
[0056] Similarly, the seventh profile 71.7 has a seventh curved cross-section T71.7 that defines an eighth convex portion 71.70 of the seventh profile 71.7 located in a fifth stagnation zone 89 of the seventh profile 71.7 when the seventh profile 71.7 is subjected to the left fraction FRG of the cooling flow FR. The seventh cross-section T71.7 also has a ninth concave portion 71.71 of the seventh profile 71.7 located in a fifth wake zone 90 of the seventh profile 71.7 when the seventh profile 71.7 is subjected to the left fraction FG of the cooling flow FR.
[0057] The eighth profile 71.8 has an eighth curved cross-section T71.8 that defines a tenth convex portion 71.80 of the eighth profile 71.8 located in a sixth stagnation zone 91 of the eighth profile 71.8 when the eighth profile 71.8 is subjected to the left fraction FRG of the cooling flow FR. The eighth cross-section T71.8 also has an eleventh concave portion 71.81 of the eighth profile 71.8 located in a sixth wake zone 92 of the eighth profile 71.8 when the eighth profile 71.8 is subjected to the left fraction FRG of the cooling flow FR.
[0058] As will be detailed later, the profiles 71.1 to 71.10 and their relative arrangement create a flow management device which allows the flow of the cooling air FR from the central radial row 25 to the radial right rows 51 and radial left row 61, and which opposes the flow of a reverse flow towards the radial right row 51 and radial left row 61 towards the central radial row 25.
[0059] During operation, fresh air drawn in by the scoop from the secondary flow En and introduced into volume V21 passes into volume V22 through the perforations 26 of row 25 (cooling flow FR). The cooling flow FR splits into two cooling flow fractions, right FD and left FRG, which cool the leading edge element 30 and the portions of the walls 50 and 60 of the fairing 22 located upstream of the flow management device 70 by impact. The right cooling flow fraction FRD then passes through the right device 72. The right cooling flow fraction FRD flows easily – with minimal pressure loss – into the volumes separating the profiles 71.1 to 71.5 to then cool by impact the wall portion 50 located downstream of the device 72 and flows, via the right radial row 51, into the exhaust volume Ve.Similarly, the left cooling flow fraction FRG easily enters - with minimal pressure losses - the volumes separating the profiles 71.6 to 71.10 to then cool by impact the wall fraction 50 located downstream of the device 73 and flow, via the left radial row 61, into the exhaust volume Ve. This results in a massive reintroduction of air from the secondary flow Fn to the exhaust flow Fe at the level of the exhaust volume Ve (figures 3 and 4).
[0060] For certain points in the flight envelope, the respective pressures and flow rates of the secondary flow Fil and the exhaust flow Fe are likely to generate a reversed flow Fi nv whose flow direction would cause gas to circulate from the exhaust volume Ve through the right radial rows 51 and left radial rows 61 towards the central radial row 25 (Figures 7 and 8). The profiles 71.1 to 71.10 disrupt the reverse flow Finv and reduce its flow rate. The concave portions 71.11, 71.21 and 71.31 of the profiles 71.1, 71.2 and 71.3 generate opposing or even vortex flows that oppose the flow of the reversed flux Finv between the right radial row 51 and the central radial row 25. Similarly, the concave portions 71.41, 71.51 and 71.61 of the profiles 71.4, 71.5 and 71.6 generate opposing or even vortex flows that oppose the flow of the reversed flux Finv between the left radial row 61 and the central radial row 25.
[0061] This results in a passive flow control device 70, in that it does not require an external energy input, unlike, for example, a solenoid valve system. Furthermore, the flow control device 70 consists exclusively of parts (profiles 71.1 to 71.10) that are fixed relative to the internal mast 21 and the casing 22, unlike, for example, a valve system. The flow control device 70 establishes fluidic diodicity (or anisotropic flow) between the exhaust volume Ve and the internal volume V21, which significantly reduces the establishment of a reverse flow Finv between these two volumes. The parameter used to quantify this phenomenon is called diodicity and is defined as the ratio between the pressure drop measured during the upstream to downstream flow of the fluid and that measured in the downstream to upstream direction through the flow control device 70.This diodicity, denoted Di, is less than 1, thus reflecting a preferential behavior of the flow in the upstream -> downstream direction.
[0062] As shown in Figure 3, and according to this first embodiment, a first distance di, measured along the axial direction X and separating the first straight device 72 from the inlet port 26, is less than a second distance d2, measured along the axial direction X and separating the first straight device 72 from the outlet port 52. Similarly, the distance di, measured along the axial direction X and separating the first straight device 72 from the inlet port 26, is less than a second distance d2, measured along the axial direction X and separating the first straight device 72 from the outlet port 52. For the purposes of determining the distances dl, d2, d'i and d'2, the position used for devices 72 and 73 corresponds to the most upstream portion of the device in question.
[0063] Elements identical or analogous to those previously described shall bear the same numerical reference in the following description of a second and a third embodiment of the invention. With reference to Figures 9 to 12, the flow management device 70 here comprises fourteen profiles 171.1 to 171.14 extending within the internal volume V20 in a direction D71 substantially parallel to the main axis A20 along the entire height (considered along the main axis A20) of the arm 20 and positioned in a staggered pattern. More specifically, the device 70 comprises a first right-hand device 72 grouping profiles 171.1 to 171.7 and a second left-hand device 73 grouping profiles 171.8 to 171.14.The device 72 is positioned between the central radial row 25 and the right radial row 51 so as to intercept the right fraction of cooling flow FR -designated FRD- which flows between the central radial row 25 and the right radial row 51. Symmetrically, the device 73 is positioned between the central radial row 25 and the left radial row 61 so as to intercept the left fraction of cooling flow FR -designated FG - which flows between the central radial row 25 and the left radial row 61.
[0064] The device 72 comprises a straight external partition 172.1 and a straight internal partition 172.2, which are joined together. Partition 172.1 is connected to the casing 22, and partition 172.2 is connected to the internal mast 21. Partition 172.1 is composed of the first profile 171.1, the second profile 171.2, the third profile 171.3, and the fourth profile 171.4, all joined together. Partition 172.2 is composed of the fifth profile 171.5, the sixth profile 171.6, the seventh profile 171.7, and the eighth profile 171.8, all joined together.
[0065] The device 73 comprises a left-hand external partition 173.1 and a left-hand internal partition 173.2, which are joined together. Partition 172.1 is connected to the casing 22, and partition 172.2 is connected to the internal mast 21. Partition 172.1 is composed of the first profile 171.1, the second profile 171.2, the third profile 171.3, and the fourth profile 171.4, all joined together. Partition 172.2 is composed of the fifth profile 171.5, the sixth profile 171.6, the seventh profile 171.7, and the eighth profile 171.8, all joined together.
[0066] The first profile 171.1 has a first curved cross-section T171.1 (considered in a plane P orthogonal to the direction D71) which defines a first convex portion 171.100 of the first profile 71.1 located in a first stagnation zone 181 of the first profile 171.1 when the first profile 171.1 is subjected to the straight fraction F RDof cooling flow FR. The first cross section T171.1 also has a second concave portion 171.101 of first profile 171.1 located in a first wake zone 182 of first profile 171.1 when first profile 171.1 is subjected to the right fraction FRD of cooling flow FR.
[0067] The second profile 171.2 has a second cross section T171.2 which defines a third portion 171.20 of the second profile 171.2 which is flat and extends into the first wake zone 182 and a fourth portion 171.21 of the second profile 171.2 which is curved and is located in a second wake zone 183 of the second profile 171.2.
[0068] The third profile 171.3 has a third cross section T171.3 which defines a fifth portion 171.30 of the third profile 171.3 which is flat and extends into the second wake zone 183 and a sixth portion 171.31 of the third profile 171.3 which is curved and is located in a third wake zone 184 of the third profile 171.3.
[0069] The right external partition 172.1 terminates with the fourth profile 171.4 which has a fourth cross section T171.4 which defines a seventh portion 171.40 of the fourth profile 171.4 which is flat and extends into the third wake zone 184 and an eighth portion 171.41 of the fourth profile 171.4 which is also flat and is located in a fourth wake zone 185 of the fourth profile 171.4.
[0070] The fifth profile 171.5 has a fifth curved cross-section T171.5 which defines a ninth convex portion 171.50 of the fifth profile 171.5 located in a fifth stagnation zone 186 of the fifth profile 171.5 when the fifth profile 171.5 is subjected to the straight fraction FRD of the cooling flux FR. The fifth cross-section T.s also has a tenth concave portion 171.51 of the fifth profile 171.5 located in a fifth wake zone 187 of the fifth profile 171.5 when the fifth profile 171.5 is subjected to the straight fraction FRD of the cooling flux F.
[0071] The sixth profile 171.6 has a sixth cross section T171.6 which defines an eleventh portion 171.60 of the sixth profile 171.6 which is flat and extends into the fifth wake zone 187 and a twelfth portion 171.61 of the sixth profile 171.6 which is curved and is located in a sixth wake zone 188 of the sixth profile 171.6.
[0072] The right internal partition 172.2 terminates with The seventh profile 171.7 has a seventh cross section T171.7 which defines a thirteenth portion 171.70 of seventh profile 171.7 flat which extends into the sixth wake zone 188 and a twelfth portion 171.71 of seventh profile 171.7 which is curved and which is located in a seventh wake zone 189 of the seventh profile 171.7.
[0073] Identical provisions apply, symmetrically, to profiles 171.8 to 171.14 of the second left device 73.
[0074] During operation, fresh air drawn in by the scoop from the secondary flow FII and introduced into volume V21 passes into volume V22 through the perforations 26 of row 25 (cooling flow FR). The cooling flow F splits into two cooling flow fractions, right FD and left FRG, which cool the leading edge element 30 and the portions of the walls 50 and 60 of the fairing 22 located upstream of the flow management device 70 by impact. The right cooling flow fraction FRD then passes through the right device 72. The right cooling flow fraction FRD flows easily – with minimal pressure loss – into the volume separating the partitions 172.1 and 172.2 to then cool by impact the wall portion 50 located downstream of the device 72 and flows, via the right radial row 51, into the exhaust volume Ve.Similarly, the left cooling flow fraction FRG easily enters - with minimal pressure losses - the volume separating partitions 173.1 and 173.2 to then cool by impact the wall fraction 60 located downstream of device 73 and flow, via the left radial row 61, into the exhaust volume Ve. This configuration is shown in figure 10.
[0075] For points in the flight domain where the respective pressures and flow rates of the secondary flow Fil and exhaust flow Fe generate a reversed flow Fj nv whose flow direction results in gas circulation from the exhaust volume Ve through the right radial rows 51 and left radial rows 61 towards the central radial row 25 (Figure 12). Profiles 171.1 to 171.14 disrupt the reverse flow Fj nvand reduce its flow rate. The concave portions 171.101, 171.21, 171.31, of the profiles 171.1, 71.2 and 71.3 generate opposing or even vortex flows that counteract and oppose the flow of the reversed flux Finv between the right radial row 51 and the central radial row 25. Similarly, the concave portions 71.41, 71.51 and 71.61 of the profiles 71.4, 71.5 and 71.6 generate opposing or even vortex flows that counteract and oppose the flow of the reversed flux Finv between the left radial row 61 and the central radial row 25.
[0076] As shown in Figure 9, and according to this second embodiment, a first distance di, measured along the axial direction X and separating the first straight device 72 from the inlet port 26, is less than a second distance d2, measured along the axial direction X and separating the first straight device 72 from the outlet port 52. Similarly, the distance di, measured along the axial direction X and separating the first straight device 72 from the inlet port 26, is less than a second distance d2, measured along the axial direction X and separating the first straight device 72 from the outlet port 52. For the purposes of determining the distances dl, d2, d'i and d'2, the position used for devices 72 and 73 corresponds to the most upstream portion of the device in question.
[0077] According to a third embodiment of the invention shown in Figure 13, the exhaust housing arm 20 comprises a flow management device 70 whose configuration is modified to optimize the distribution of internal flows. In this embodiment, the right radial row 51 and left radial row 61 are located near the trailing edge 40 of the housing 22.
[0078] The flow management device 70 includes a first right device 72 which groups the profiles 171.1 to 171.7 and a second left device 73 which groups the profiles 171.8 to 171.14. In this configuration, the devices 72 and 73 are also positioned close to the trailing edge 40, so that the flow of the cooling flow FR is directed in a more controlled manner towards the radial rows 51 and 61.
[0079] Thus, a first distance di, measured along the axial direction X and separating the flow management device 70 from the inlet port 26, is greater than a second distance d2, measured along the axial direction X and separating the flow management device 70 from the outlet port 52, 62. This arrangement makes it possible to strengthen the fluidic diodicity effect by limiting the establishment of a reverse flow Finv between the exhaust volume Ve and the internal volume V21, while maintaining an optimal distribution of flows within the exhaust crankcase arm 20.
[0080] In operation, the fresh air taken in by the scoop in the secondary flow Fil is introduced into the internal volume V21 before passing through the flow management device 70, whose arrangement allows the flow to be channeled towards the right radial rows 51 and left radial rows 61 located near the trailing edge 40. The interaction between the profiles 171.1 to 171.14 and the flows contributes to generating stagnation and wake zones which significantly reduce the reverse flow Finv and optimize the rejection of the cooling flow FR into the exhaust volume Ve.
[0081] As seen in Figure 13, and according to this first embodiment, a first distance of 1zmeasured along the axial direction X and separating the first straight device 72 from the inlet port 26, is less than a second distance d2, measured along the axial direction X and separating the first straight device 72 from the outlet port 52. Similarly, the distance di measured along the axial direction X and separating the first straight device 72 from the inlet port 26, is less than a second distance d2, measured along the axial direction X and separating the first straight device 72 from the outlet port 52. For the purposes of determining the distances dl, d2, d'i and d'2, the position used for devices 72 and 73 corresponds to the most upstream portion of the device in question.
[0082] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims. In particular,
[0083] Although here the crankcase arm includes an internal mast and a casing, the invention also applies to a crankcase arm without an internal mast and in which the casing would also take over the mechanical forces;
[0084] Although here the orifices are circular in shape extending parallel in a radial direction, the invention also applies to other types of injection orifices, such as oblong or any other shaped orifices, or orifices extending in non-radial directions;
[0085] Although here the crankcase arm includes a mast with a single central radial row that fluidically links the cooling air source and the internal volume of the exhaust crankcase arm, the invention also applies to other types of intake ports for a cooling airflow such as, for example, a duct opening directly into the internal volume of the exhaust crankcase arm without passing through the inside of the mast or one or more slots made in the internal mast;
[0086] Although here the casing of the exhaust crankcase arm includes two radial rows of circular orifices, the invention also applies to other types of outlet ports such as, for example, a radially extending slot, oblong orifices, or orifices of any shape, and which can be distributed over several rows, oriented radially, axially or in any way;
[0087] Although here the flow management device comprises ten profiles, the invention also applies to other flow management device configurations, such as a device comprising a single profile, a plurality of profiles comprising between two and ten profiles, or more than ten profiles.
[0088] Although the turbomachine is described here as comprising several identical exhaust casing arms, the invention also applies to configurations where these arms are not strictly identical. For example, some exhaust casing arms could have variations in geometry, orientation, or dimensions depending on integration constraints, specific cooling requirements, or the aerodynamic characteristics specific to each area of the turbomachine.
[0089] Although the flow management device is described here as comprising profiles extending the full height of the exhaust housing arm, the invention also applies to configurations where these profiles extend over only a portion of that height. For example, the profiles could be arranged on a specific section of the internal volume to optimize the direction of the cooling airflow or to limit local disturbances. Similarly, a variation in the vertical distribution of the profiles could be considered to accommodate integration constraints or the need for differentiated thermal management along the exhaust housing arm.
Claims
DEMANDS 1. Turbomachine (1) comprising a cylindrical exhaust casing (8) with axis (AX) extending along an axial direction (X) defining an exhaust volume (Ve) through which an exhaust flow (Fe) flows, the exhaust casing (8) being connected to a frame (10) of the turbomachine (1) by an exhaust casing arm (20) extending essentially radially along a principal axis (A20), the exhaust casing arm (20) comprising a casing (22) which delimits an internal volume (V20) of the exhaust casing arm (20), the casing (22) comprising an outlet port (52, 62) which establishes fluidic communication between the internal volume (V20) of the exhaust casing arm (20) and the exhaust volume (Ve), the exhaust casing arm (20) also comprising an inlet port (26) of a cooling airflow (FR) in the internal volume (V20), the exhaust crankcase arm (20) also comprising a passive flow management device (70) arranged to permit the flow of cooling air (F) from the intake port to the outlet port (52, 62), the flow management device (70) also being arranged to counteract the flow of a reverse flow (Fi nv ) from the outlet port (52, 62) to the inlet port (26), in which the flow management device (70) includes a first profile (71.1, 171.1) extending into the internal volume (V20) in a direction substantially parallel to the main axis (A20).
2. Turbomachine (1) according to claim 1, wherein a first distance measured along the axial direction separating the flow management device (70) from the inlet port (26) is less than a second distance measured along the axial direction separating the flow management device (70) from the outlet port (52, 62).
3. Turbomachine (1) according to claim 1 or 2, wherein the exhaust casing arm (20) comprises an internal mast (21) around which the casing (22) extends.
4. Turbomachine (1) according to claim 1, wherein the first profile (71.1, 171.1) has a curved cross-section (T71.1, T171.1) that defines a first portion (71.100, 171.100) of the first profile (71.1, 171.1) located in a first stagnation zone (81, 181) of the first profile (71.1, 171.1) when the first profile (71.1, 171.1) is subjected to the cooling airflow (FR) and a second portion (71.11, 171.101) of the first profile (71.1, 171.1) located in a first wake zone (82, 182) of the first profile (71.1, 171.1) when the first profile (71.1, 171.1) is subjected to the flow cooling air (FR).
5. Turbomachine (1) according to claim 4, wherein the first portion (71.100, 171.100) of first profile (71.1, 171.1) is convex.
6. Turbomachine (1) according to claim 4 or 5, wherein the second portion (71.11, 171.101) of first profile (71.1, 171.1) is concave.
7. Turbomachine (1) according to any one of the preceding claims, wherein the flow management device (70) comprises a plurality of profiles (71.1-71.10, 171.1-171.14) extending in the internal volume (V20) in a direction substantially parallel to the main axis (A20) and which are positioned in a staggered pattern.
8. Turbomachine (1) according to any one of the preceding claims, wherein the first profile (171.1) is connected to the internal mast or the casing.
9. Turbomachine (1) according to any one of the preceding claims, wherein the flow management device (70) comprises a second profile (171.2) which has a cross section (T171.20) which defines a third portion (171.20) of the second profile (171.2) which is flat and which extends at least partially into the first wake zone (182), the second profile (171.20) also comprises a fourth portion (171.21) of the second profile (171.20) which is curved and which is located in a second wake zone (183) of the second profile (171.20).