Inner casing with integrated heat exchanger pipes

Abstract

The present invention relates to an inner casing (1) of a turbomachine (110), comprising an inner shroud (11) extending around an axis (A) from upstream to downstream in a direction of flow of an air flow (G) produced by the turbomachine, further comprising an outer shroud (12) surrounding the inner shroud (11) so as to define a cooling channel (173) through which a portion (F) of the air flow (G) flows, the inner shroud (11) comprising an inner surface (13), the inner casing (1) comprising a hydraulic pipe (3) integrated into the inner surface (13), the hydraulic pipe (3) comprising, upstream, an upstream interface (31) configured to be placed in fluid communication with a heat exchanger (4) located upstream in the cooling channel, and, downstream, a downstream interface (32) located at a downstream end of the inner surface (13) or projecting axially relative to a downstream end of the surface shroud (13), the downstream interface (32) being configured to be placed in fluid communication with a device.

Description

[0001] Internal casing with integrated heat exchanger ducts

[0002] TECHNICAL FIELD

[0003] This presentation concerns the general field of propulsion systems, in particular unfaired turbomachinery with at least two flow paths, intended for aircraft propulsion. Turbomachinery with at least two flow paths refers more specifically to turbomachines known as "double-flow turbomachines" or "triple-flow turbomachines".

[0004] This presentation relates more particularly to a turbomachine casing comprising a hydraulic conduit associated with a heat exchanger of an aircraft turbomachine with at least two flows, and to an aircraft turbomachine with at least two flows equipped with such a casing.

[0005] STATE OF THE ART

[0006] A turbomachine has a longitudinal axis around which it extends and typically comprises, from upstream to downstream in the direction of gas flow, a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, and a low-pressure turbine including an exhaust casing. The air entering the turbomachine is compressed by the fan and then splits into a primary airflow, which passes through the primary casing, and a secondary airflow that bypasses the primary airflow, and optionally a tertiary airflow that bypasses the primary flow.

[0007] Furthermore, such a turbomachine typically includes an air-cooled oil coder (ACOC) to cool the oil in the turbomachine's lubrication circuit. Oil cooling is a major issue, particularly in turbomachines using a gear reducer to drive the fan (a shrouded blade or a propeller), as the heat from the gears and bearings is absorbed by the oil that lubricates and cools these components. Such a reducer has a high reduction ratio and transmits high torques, which necessitates efficient cooling and therefore a significant oil flow rate. Appropriate means, especially air-cooled oil heat exchangers, are thus required to cool this oil.The hydraulic interfaces of each air / oil heat exchanger include at least one inlet port for supplying oil and one outlet port for returning oil.

[0008] Currently, air / oil heat exchangers are mounted in a secondary or tertiary airflow with hydraulic interfaces provided by a manifold in a central compartment of the turbomachine, between two casings, one upstream and one downstream. The upstream casing is typically an inter-compressor casing, and the downstream casing is a structural, or "transition" casing. Consequently, access to the hydraulic connections is impossible once the transition casing is mounted downstream. This is because the equipment mounted on the hub of the upstream casing is housed below the downstream transition casing, making it inaccessible once the latter is installed. This complicates the assembly of adjacent equipment and piping during the initial turbomachine assembly and also hinders maintenance operations throughout its lifecycle.

[0009] DESCRIPTION OF THE INVENTION

[0010] One aim of the invention is to have a casing that allows for better hydraulic connections with a heat exchanger.

[0011] In this respect, the invention proposes an internal casing of a turbomachine, comprising an internal shell extending around an axis from upstream to downstream in a direction of circulation of an airflow produced by the turbomachine, further comprising an external shell surrounding the internal shell so as to define a cooling channel in which a part of the airflow circulates, the internal shell comprising in an internal surface a hydraulic conduit, the hydraulic conduit comprising upstream an upstream interface configured to be put into fluidic communication with a heat exchanger located upstream in the cooling channel and downstream a downstream interface located at the level of a downstream end of the internal shell or projecting axially from a downstream end of the internal shell, the downstream interface being configured to be put into fluidic communication with a piece of equipment.

[0012] The casing according to the invention is advantageously complemented by the following features, taken alone or in one of their technically feasible combinations:

[0013] - the upstream interface includes one of an input port configured to supply oil to a fluidic communication device and an output port configured to supply oil to the hydraulic line, the downstream interface includes the other of the output port and the input port;

[0014] - the downstream interface includes an O-ring or a sealing plate configured to ensure sealing;

[0015] - several hydraulic pipes distributed in the internal surface of the inner shell, the inner shell comprising internal conduits configured to connect the hydraulic pipes in fluidic communication.

[0016] The invention also relates to a turbomachine comprising such an internal casing, the turbomachine further comprising upstream of the internal casing an intermediate casing through which the cooling channel passes, the intermediate casing comprising an external intermediate shell fixed to the external shell and a hub, the turbomachine further comprising a heat exchanger located in the cooling channel between the external intermediate shell and the hub, the heat exchanger being axially interposed between the hub and the internal shell so as to be fluidic communication with the hydraulic line.

[0017] The turbomachine according to the invention is advantageously complemented by one of the following features, taken alone or in combination:

[0018] - the heat exchanger includes a double ball joint or an elastic coupler configured to connect the heat exchanger and the hydraulic line;

[0019] - The heat exchanger and the hydraulic line are connected by a connecting tube comprising two ends, each end comprising an O-ring,

[0020] - the intermediate casing is an inter-compressor casing located between a low pressure compressor and a high pressure compressor.

[0021] The invention also relates to an aircraft equipped with such a turbomachine.

[0022] The invention also relates to a method for manufacturing an internal casing as described above, comprising a casting step for the outer and inner shells and a machining step for the hydraulic line by axial drilling of the inner shell. The casting step is advantageously complemented by forming a first radially external portion of the hydraulic line within the inner shell. The method further comprises a casting step for a second radially internal portion of the hydraulic line, the first and second portions being configured to be welded together in a welding step to form the hydraulic line.

[0023] DESCRIPTION OF THE FIGURES

[0024] Other features, purposes and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0025] Figure 1 is a cross-sectional view of an unfaired fan turbomachine;

[0026] Figure 2 is a detailed cross-sectional view of a cooling duct according to one embodiment of the invention;

[0027] Figure 3 is a cross-sectional view of an internal casing according to one embodiment of the invention;

[0028] Figure 4 is a diagram of a connecting tube according to one embodiment of the invention;

[0029] Figure 5 is a diagram showing the steps of a manufacturing process for a housing according to the invention;

[0030] Figure 6 is a diagram showing the steps of a method for assembling a turbomachine according to the invention.

[0031] Across all figures, similar elements bear identical references.

[0032] DETAILED DESCRIPTION OF THE INVENTION

[0033] Figure 1 shows a turbomachine 110 according to an embodiment of the invention. The turbomachine 110 extends along an axis A and comprises an unfaired fan 121, also called a propeller, which rotates about the axis A. Downstream of this propeller, a fixed stator 131 straightens the airflow produced by the propeller in the axial direction, in order to optimize the thrust of the propulsion system. The stator blades 131 preferably have variable pitch.

[0034] The turbomachine 110 also includes a main channel 171 which extends through the turbomachine 110 from upstream to downstream in a direction G of gas flow in the turbomachine, essentially parallel to axis A, from a main inlet 170 to a main outlet 180 opening outside the housing of the turbomachine 110.

[0035] The main channel 171 is configured to circulate a primary airflow in a general gas flow direction, represented by arrow G in Figure 1, from the main inlet 170 to the main outlet 180, which is therefore located downstream of the main inlet 170.

[0036] In the following description, the terms "radially internal" and "radially external" refer to the radial position of an element with respect to the axis A, and the terms upstream and downstream are defined with respect to the general flow direction G of the gases through the turbomachine 110. Between the propeller 121 and the rectifier 131, the turbomachine has in its casing the main inlet 170 of the main channel 171.

[0037] In this same embodiment of the invention, and along the main channel 171, the turbomachine 110 comprises successively in the direction G of gas flow:

[0038] - at least one compression stage 145 forming, for example, a compression section, the compression section possibly comprising upstream a low-pressure compressor and downstream a high-pressure compressor 127,

[0039] - a combustion chamber 128.

[0040] A compression stage 145 is defined as an assembly consisting of a rotating blade wheel (or rotor with rotating blades) and a stationary blade wheel (or stator with stationary blades), the rotating blade wheel being located either upstream or downstream of the stationary blade wheel. By rotating the rotating blade wheel of this compression stage 145, it can create an increase in air pressure downstream of the stage compared to the upstream side.

[0041] In the main channel 171, the turbomachine 110 further comprises, downstream of the combustion chamber 128, a turbine section which may include upstream a high-pressure turbine 129, and downstream a low-pressure turbine 150. The turbomachine is also supplied with air by the main channel 171.

[0042] The main channel 171 is configured to supply air entering through the air inlet 170 to at least one compression stage 145 and the combustion chamber. More precisely, it is the air compressed by the at least one compression stage 145 that is displaced through the main channel 171 to the combustion chamber and supplies it. This supply occurs in the flow direction G from the main inlet 170 towards the compression stages.

[0043] The turbomachine 110 also includes an auxiliary channel 173, or cooling channel 173, which extends from an auxiliary inlet opening into the main channel 171 to an auxiliary outlet opening outside the turbomachine 110. The auxiliary inlet is located upstream of each compression stage 145 of the main channel 171. The main channel 171 is separated from the cooling channel 173 by a central compartment 6 (the "core compartment" in Anglo-Saxon terminology). Thus, the cooling channel 173 is located radially further outward than the main channel 171; that is, the main channel 171 lies between the axis A of the turbomachine 110 and the cooling channel 173. The cooling channel 173 may have an annular shape and extend around the axis A of the turbomachine 110, around the central compartment 6.Air outlet 178 is located downstream of guide vanes 131 and upstream of main outlet 180.

[0044] At least one heat exchanger 4 is located in the cooling channel 173, attached to an inter-compressor housing 5, or intermediate housing 5. More precisely, the heat exchanger 4 is situated between an external intermediate ferrule 52 and a hub 51 belonging to the inter-compressor housing 5 and defining the cooling channel 173. The heat exchanger 4 is configured to be cooled by the air flowing through the cooling channel 173. The heat exchanger 4 can, in particular, be used to cool a gearbox 160 configured to drive the upstream propeller 121. Various heat exchanger technologies 4 can be considered, such as volumetric heat exchangers, surface heat exchangers, finned heat exchangers, etc.

[0045] Referring to Figure 2, the turbomachine 110 includes, downstream of the inter-compressor housing 5, an internal housing 1. The internal housing 1 is an intermediate housing between the inter-compressor housing 5 and the air outlet 178. The internal housing 1 comprises an internal shell 11, extending around an axis A extending from upstream to downstream in the direction of airflow G, and an external shell 12, surrounding the internal shell 11. Between the internal shell 11 and the external shell 12 is the cooling channel 173 through which a portion F of the airflow G flows. Advantageously, the intermediate housing 5 is an inter-compressor housing located between a low-pressure compressor and a high-pressure compressor.

[0046] The inner casing 1 can be a structural casing comprising arms 15 connecting the outer shell 12 to the central compartment 6, in order to give greater rigidity to the turbomachine 110. These arms 15 extend radially with respect to the axis A and are therefore arranged across the cooling channel 173. Each arm 15 fulfills a structural function and ensures the relative positioning of the inner casing 1 with the central compartment 6.

[0047] The internal ferrule 11 includes in an internal surface 13 a hydraulic conduit 3.

[0048] It is specified here that the internal surface 13 of the internal shell 11 designates, in other words, a radially internal wall of this shell 11, and that the integration of the hydraulic conduit 3 into the internal surface 13 means that the conduit 3 is contained within the thickness of said wall. In other words, the hydraulic conduit is integrated within the thickness of the internal shell 11.

[0049] The hydraulic line 3, for example, protrudes from the inner shell 11 into a central compartment 6 (the "core compartment" in Anglo-Saxon terminology). Alternatively, the inner shell 11 may include an integrated hydraulic line 3 so as not to pass through the central compartment 6. The hydraulic line 3 includes upstream an upstream interface 31, configured to be in fluidic communication with the heat exchanger 4 located upstream in the cooling channel 173, and downstream a downstream interface 32 that protrudes axially from the inner shell 11. In other words, the downstream interface 32 is not contiguous with the inner surface 13 and extends beyond the inner shell 11, making it accessible.The downstream interface 32 is configured to be put into fluidic communication with equipment located downstream, for example a filter, a lubrication group including a supply pump and recovery pumps, magnetic plugs, etc.

[0050] To ensure the oil supply to the heat exchanger 4, the upstream interface 31 preferably includes an inlet port configured to supply oil to a fluidically connected device, preferably the heat exchanger 4, and an outlet port configured to supply oil to the hydraulic line 3. The downstream interface 32 also includes an outlet port and an inlet port. Of course, the inner shell 11 can include several hydraulic lines 3, and the upstream interfaces 31 and downstream interfaces 32 may then include only one or the other of an outlet port and an inlet port. In this case, the inner shell 11 may include internal channels 14 configured to provide fluidic communication between the various hydraulic lines 3, as illustrated in Figure 3. This is particularly advantageous for supplying oil to several heat exchangers 4 positioned in series.

[0051] To ensure sealing between the heat exchanger 4 and the hydraulic line 3, the inner shell 11 is advantageously in planar support or in cylindrical contact with the heat exchanger 4, so that each inlet and outlet port of the upstream interface 31 faces respectively an outlet port and an inlet port of the heat exchanger 4 when the inner casing 1 is mounted on the turbomachine 110. Downstream, sealing can be ensured by an O-ring or a gasket plate.

[0052] The inner casing 1 is fixed to the upstream inter-compressor casing 5, for example, with a bolted flange connecting the outer shell 12 and the outer intermediate shell 52 of the inter-compressor casing 5. Conversely, the inner shell 11 of the inner casing 1 is preferably not in contact with the hub 51, because the heat exchanger 4 is partially axially interposed between the hub 51 and the inner shell 11 in order to be connected to the upstream interface 31 of the hydraulic line 3. The heat exchanger 4 thus protrudes into the central compartment 6 if the hydraulic line 3 is located there. Advantageously, the heat exchanger 4 includes a double ball joint or an elastic coupler configured to provide a flexible connection with the hydraulic line 3, which allows the position to be adjusted during the mounting of the casings 1 and 5.Alternatively, the hydraulic line 3 and the heat exchanger 4 can be connected by a connecting tube 41 comprising two ends 42, each end including an O-ring 43, i.e., a so-called "diabolo tube", "dog bone" or "jumper tube" in Anglo-Saxon terminology. This fluid connection can also be made by nipples or three- or four-point flanges.

[0053] Referring to Figure 4, a manufacturing process for the inner casing 1 includes a fabrication step (step S1) by casting and / or machining of the outer ferrule 12, inner ferrule 11, and optionally the arms 15. Casting is understood to mean all known processes for forming an alloy into a single piece, for example, melting, casting, demolding, deburring, and any associated heat treatments. Machining is understood to mean all known processes for producing a part by removing material. Casting and machining can optionally be replaced by a process using additive manufacturing. Subsequently, a machining step (step S3a) of the hydraulic line 3 is performed by axially drilling the inner ferrule 11.

[0054] Alternatively, if the hydraulic line 3 includes a bend, the casting step (step S1) then comprises the production of a first part 3a of the hydraulic line 3. This first part 3a corresponds to a radially external half, or half-shell, of the hydraulic line 3, chosen to expose the internal cross-section of the hydraulic line 3. The first part 3a is formed from the solid core of the inner casing 1, that is, during the casting and / or machining of the inner ferrule 11. The first part 3a is thus a single piece with the inner ferrule 11. A second casting and / or machining step (step S2) then comprises the production of a second part 3b corresponding to a complementary half with the first part 3a of the hydraulic line 3. In other words, the second part 3b is a radially external half-shell of the hydraulic line 3.The two parts 3a, 3b are joined during a welding step (step S3b) which makes it possible to obtain an internal casing 1 including a functional hydraulic line 3.

[0055] With reference to Figure 5, the inner casing 1 can be mounted on the turbomachine 110 by moving it axially from downstream to upstream against the inter-compressor casing 5 during a translation step (step E1) of a turbomachine 110 assembly process. Advantageously, centering pins on the arms 15 guide the inner casing 1 in translation to ensure proper alignment of the interfaces, in particular the ports of the upstream interface 31 with the ports of the heat exchanger 4. Preferably, the inner casing 1 includes three mounting pins configured to cooperate with bores, one pin with very little clearance with a bore it will guide and one or two other pins with larger clearances (for example, pins being cylinders with flats) to allow a degree of freedom during the mounting of the inner casing 1.Once the inner casing 1 is in the desired position, it is fixed to the inter-compressor casing 5 during a fastening step (step E2), for example by bolting the outer ferrule 12 to the outer intermediate ferrule 52 using a flange. The arms 15 can also be bolted to arms of the inter-compressor casing 5.

[0056] Compared to the current state of the art, a turbomachine 110 as described herein is easier to produce and maintain, thanks to the structure of the internal casing 1. Indeed, the position of the hydraulic line 3 and its integration into the internal shell 11 facilitates the assembly and configuration of the interfaces 31 and the heat exchanger 4. This integration also saves space, as the number of pipes to be installed upstream of the central compartment 6 is reduced. Finally, since the downstream interface 32 of the hydraulic line 3 protrudes axially from the internal shell 11, it remains accessible for maintenance operations.

Claims

DEMANDS 1. Internal casing (1) of a turbomachine (110), comprising an internal shell (11) extending around an axis (A) from upstream to downstream in the direction of flow of an air stream (G) produced by the turbomachine, further comprising an external shell (12) surrounding the internal shell (11) so as to define a cooling channel (173) in which a portion (F) of the air stream (G) flows, the internal shell (11) comprising an internal surface (13), the internal casing (1) comprising a hydraulic line (3) integrated into the internal surface (13), the hydraulic line (3) comprising upstream an upstream interface (31) configured to be in fluidic communication with a heat exchanger (4) located upstream in the cooling channel and downstream a downstream interface (32) located at a downstream end of the internal surface (13) or projecting axially from a downstream end of the surface ferrule (13),the downstream interface (32) being configured to be in fluidic communication with a piece of equipment.

2. Internal housing (1) according to claim 1, wherein the upstream interface (31) comprises one of an inlet port configured to supply oil to a fluidic communication device and an outlet port configured to supply oil to the hydraulic line (3), the downstream interface (32) comprising the other of the outlet port and the inlet port.

3. Internal housing (1) according to claim 2 in which the downstream interface (32) includes an O-ring or a sealing plate configured to ensure sealing.

4. Inner casing (1) according to any one of claims 1 to 3, comprising several hydraulic conduits (3) distributed in the internal surface (13) of the inner shell (11), the inner shell (11) comprising internal conduits (14) configured to connect the hydraulic conduits (3) fluidically.

5. Turbomachine (110) comprising an inner casing (1) according to any one of claims 1 to 4, comprising upstream of the inner casing (1) an intermediate casing (5) through which the cooling channel (173) passes, the intermediate casing (5) comprising an external intermediate ring (52) fixed to the external ring (12) and a hub (51), the turbomachine further comprising a heat exchanger (4) located in the cooling channel (173) between the external intermediate ring (52) and the hub (51), the heat exchanger (4) being axially interposed between the hub (51) and the inner ring (11) so as to be fluidic communication with the hydraulic line (3).

6. Turbomachine (110) according to claim 5, wherein the heat exchanger (4) comprises a double ball joint or an elastic coupler configured to connect the heat exchanger (4) and the hydraulic line (3).

7. Turbomachine (110) according to claim 5, wherein the heat exchanger (4) and the hydraulic line (3) are connected by a connecting tube (41) comprising two ends (42), each end comprising an O-ring (43).

8. Turbomachine (110) according to claim 5, wherein the intermediate casing (5) is an inter-compressor casing located between a low-pressure compressor and a high-pressure compressor.

9. Manufacturing method (S) of an internal casing (1) according to any one of claims 1 to 4, comprising a manufacturing step (S1) by casting of the external (12) and internal (11) shells and a machining step (S3a) of the hydraulic conduit (3) by axial drilling of the internal shell (11).

10. Manufacturing method (S) according to claim 9, wherein the casting step (S1) comprises the production in the inner shell (11) of a first radially external part (3a) of the hydraulic line (3), the method further comprising a casting step (S2) of a second radially internal part (3b) of the hydraulic line (3), the first and second parts (3a, 3b) being configured to be welded in a welding step (S3b) to form the hydraulic line (3).

11. Aircraft comprising a turbomachine (110) according to any one of claims 5 to 8.

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