Catheter arrangement

Abstract

A gas turbine engine has a core flow path and an outer flow path positioned at a greater radial displacement from an axis of rotation of the engine than the core flow path. The gas turbine engine also has a cavity to provide fluid communication between a bleed passage for communicating air from the core flow path to the cavity and a conduit for communicating air from the cavity to the external flow path. The cavity has a downstream cavity wall. The conduit has a circumferentially extending opening that provides access through the downstream lumen wall adjacent a radially outer lumen wall of the cavity.

Description

Background Art

[0001] The present invention relates to a duct arrangement and in particular, but not exclusively, to a duct arrangement for conveying air from a cavity of a gas turbine engine to an external flow path.

[0002] In order to prevent the compressor of a gas turbine engine from stalling under different engine operating conditions, a bleed passage may be provided, typically within the intermediate compressor structure. The bleed passage is arranged to release air out of the main flow path or the core flow path in order to divert air away from the compressor and prevent the compressor from stalling under certain operating conditions. This allows the gas turbine engine to operate continuously under a wide range of operating conditions.

[0003] The air released through the bleed air passage is delivered into a cavity (which may be referred to as a chamber, bleed air plenum, or fire zone compartment.) The cavity collects the air before it is released into another flow path, such as a bypass duct around the engine core.

[0004] It may be difficult to design an engine that involves a bleed path that directs bleed air from a core flow path through the engine structure to another flow path into which the air is bleed. This difficulty may be due to the need for a cavity, and in particular the need for downstream walls of the cavity to accommodate multiple components of the engine. Examples of such components include gearboxes, thrust links, actuators, engine monitoring and control equipment, air and fluid pipes, cables and wiring harnesses. Therefore, integration of all of these components can prove difficult. Even if there is space for all of these components, the manufacture of the conduit can prove difficult due to the constrained nature of this area.

[0005] Additionally, introducing bleed air into the bypass duct, or more generally, into the external flow path, may disrupt air flow through the external flow path, particularly if the bleed air is introduced at an angle that deviates significantly from the direction of air flow in the external flow path.

[0006] Another problem associated with bleed air passages is that particles and / or water in the bleed air extracted from the core flow path may collect and accumulate in the cavity. Summary of the invention

[0007] Various aspects of the invention are set out in the accompanying claims.

[0008] From a first aspect, a gas turbine engine is provided, the gas turbine engine comprising: a core flow path and an external flow path, the external flow path being positioned at a greater radial displacement from the engine's axis of rotation than the core flow path; and a cavity, the cavity being used to provide fluid communication between a bleed passage and a duct, the bleed passage being used to convey air from the core flow path to the cavity, and the duct being used to convey air from the cavity to the external flow path, the cavity having a downstream cavity wall; wherein the duct comprises a circumferentially extending opening, the circumferentially extending opening providing a passage for a radially outer cavity wall adjacent to the cavity through the downstream cavity wall.

[0009] As described herein, a conduit is provided to convey the bleed air extracted (or sucked) from the core flow path into the cavity via the bleed passage to the external flow path. The conduit is in the form of an opening extending generally circumferentially, and is arranged to define an air flow path that passes through a downstream cavity wall adjacent to the radially outer cavity wall of the cavity, i.e., the conduit passes through the downstream cavity wall at a point of maximum radial displacement from the axis of rotation of the gas turbine engine. For example, the conduit may be formed against a radially inner wall of the external flow path so as to extend adjacent to the external flow path in the direction of the airflow (i.e., downstream in the engine). In some examples, the inner wall of the external flow path may even form a portion of the outer wall of the conduit, so that the conduit is enclosed by the outer wall.

[0010] By arranging the opening to provide the passage of the radially outer cavity wall adjacent to the cavity through the opening in the downstream cavity wall, the conduit can be placed away from the most crowded area of ​​the downstream cavity wall, where it is desired to place other components (such as thrust links, actuators, engine monitoring and control equipment, air and fluid conduits, cables, wiring harnesses and / or gear boxes) so as to make it easier and better to optimize the placement of these components. In addition, in the case where the conduit is positioned in the cavity and has a relatively large radial displacement with the axis of the engine, the circumferential width of the conduit can be greater than the circumferential width of the conduit in the case where the conduit is more centrally positioned. This means that a conduit with a smaller radial height can be used, while still providing the desired cross-sectional area of ​​the conduit, thereby providing a thinner conduit through the downstream cavity wall, while still supporting the desired capacity of the air flow for venting. In this sense, the conduit can have a high aspect ratio, for example, a circumferential width greater than its height in the radial direction or a circumferential width greater than its radial height 2.5 times or more (i.e., an aspect ratio of 2.5:1). In some examples, the conduit may have an aspect ratio of 3:1 or 4:1 or 5:1.

[0011] This form of thin conduit further reduces the conduit footprint in the most crowded area of ​​the downstream cavity wall closer to the engine axis.

[0012] Furthermore, by positioning the ducts as described above, manufacturing of the engine may be made easier because more space is provided for welding and / or bolting components together, thereby avoiding the need for large single-piece castings or single prints using additive manufacturing that may increase production complexity.

[0013] The bleed air may contain water and / or particles that may accumulate in the cavity. If the conduit is positioned away from the radially outer wall of the cavity, these undesirable elements may accumulate at the bottom dead center of the engine under gravity. The downstream wall will then be used to capture these particles and water. However, as discussed herein, in the case where the conduit is positioned adjacent to the radially outer wall, at the bottom dead center of the engine, the conduit is therefore positioned at the lowest point of the cavity, and therefore any accumulated particles and water can be discharged through the conduit into the external flow path and leave the engine.

[0014] In addition, the conduit arrangement discussed herein can allow the conduit to be shortened, so that the conduit extends less along the engine in the downstream direction, compared to a conduit positioned closer to the axis of the engine. Thus, more space in the engine can be freed up in this downstream direction and on the downstream cavity wall itself.

[0015] One or more deflation valves may be provided in the deflation channel, the conduit, or otherwise on the fluid communication path between the core flow path and the external flow path, the one or more deflation valves being capable of opening and closing to selectively provide or restrict the deflation flow path. In this sense, the cavity may selectively provide fluid communication from the deflation channel to the conduit. That is, when the deflation valve is closed, the cavity may prevent fluid communication between the deflation channels, while the cavity may be configured to enable such fluid communication when the deflation valve is open.

[0016] In some examples, the external flow path may be a bypass channel that carries bypass air, or may be an intermediate flow path or a low-pressure core flow path that is arranged outside the (high-pressure) core flow path and carries air at a lower pressure than the (high-pressure) core flow path. In some examples, the gas turbine engine is provided with a plurality of ducts, wherein a subset of those ducts directs air to a first external flow path (e.g., a bypass channel), and a different subset of those ducts directs air to a second external flow path (e.g., an intermediate flow path). For example, most of the air extracted from the core flow path may be directed to an intermediate flow path / bypass channel that is arranged outside the core flow path, while a portion of the bleed-out air is directed to an outermost air flow (e.g., outside the engine nacelle) via a separate duct.

[0017] As used herein, the term "adjacent" refers to the passage provided by the conduit through the downstream cavity wall being close to the outer cavity wall of the cavity, such as shown in the accompanying drawings. As measured in the radial direction from the axis of rotation of the engine, the passage can be arranged, for example, within the outer 25% of the downstream cavity wall, the outer 15% of the downstream cavity wall, or the outer 10% of the downstream cavity wall. Functionally, the arrangement of the passage through the downstream cavity wall provided by the conduit adjacent to the outer cavity wall of the cavity enables the use of a high aspect ratio for the conduit / passage (as described in more detail below), allows the conduit to be located away from the most crowded areas of the downstream cavity wall, and provides an air flow path from the core flow path to the cavity and then through the conduit to the outer flow path.

[0018] The opening can be arranged adjacent to the radially outer wall of the cavity in a variety of ways. In some examples, this is achieved by providing an inlet for the conduit in the downstream cavity wall at a position adjacent to the radially outer wall of the cavity. Such an arrangement can be achieved relatively easily because an opening can be machined into the downstream cavity wall to provide the inlet and allow the remainder of the conduit to be installed in place against the downstream cavity wall.

[0019] In some examples, the inlet may be positioned directly against the outer wall of the cavity so that it is formed at the edge of the downstream wall. In this case, the outer wall of the cavity will define the edge of the inlet, thereby preventing water and / or particles from accumulating at bottom dead center of the engine because the inlet extends all the way to the lowest point of the cavity.

[0020] Alternatively, the conduit can extend beyond the downstream cavity wall into the cavity, wherein the entrance to the conduit is positioned inside the cavity. In this case, the conduit extends through the opening in the downstream cavity wall at the point of the radially outer cavity wall adjacent to the cavity, so that a flow path through the downstream cavity wall is provided at the outer edge of the downstream cavity wall. In the case where the entrance of the conduit is positioned inside the cavity, the entrance can be oriented to substantially align with the outlet of the deflated air introduced into the cavity. For example, the conduit entrance and the deflated passage can be oriented parallel to each other and / or positioned relative to each other in the cavity, so that the deflated air is directed to the entrance from the deflated passage. In some examples, the conduit can extend to the degree connected with the deflated passage, so as to provide a direct path from the core flow path through the cavity and into the external flow path. However, in some cases, it may be preferred to have an interval between the deflated passage and the conduit, so as to provide more space in the cavity for installing other components.

[0021] Regardless of whether the duct is directly connected to the bleed passage, by aligning the duct inlet to aim the outlet flow from the bleed passage, the duct inlet flow can be improved, thereby increasing the efficiency with which the bleed air can be directed to the external flow path, reducing the amount of particulate matter and water deposited in the cavity, and / or improving the acoustic conditions within the cavity.

[0022] In some examples, the duct (and / or the bleed channel) is arranged to redirect the received air flow. For example, the bleed channel can redirect the air received from the core flow path from a first flow direction (the flow direction that the air has in the core flow path; for example, corresponding to Figure 4 The duct may redirect the air from the second flow direction to a third flow direction (flow D'). The redirection may change the flow angle of the air by an angle between 15° and 90° and may return the air flow to a direction parallel to the first flow direction. In some examples, the duct directs the air through the downstream cavity wall in the third flow direction and further redirects the air flow to a fourth flow direction (flow E) so as to introduce the air into the external flow path. In this sense, the flow path formed by the duct and / or the bleed channel may have a generally serpentine shape or an S-shaped arrangement.

[0023] On the other side of the downstream wall of the cavity (i.e., the side opposite to the cavity), the conduit can extend substantially parallel to the external flow path and remain adjacent to the inner wall of the external flow path. In some examples, the conduit can be formed against the external flow path (or a plate wall enclosing the external flow path) so that the inner wall (or plate wall) of the external flow path at least partially encloses the conduit (e.g., forming one side of the conduit). In this case, the other wall of the conduit can be sealed to the inner wall of the external flow path so as to contain the venting flow in the conduit.

[0024] In some examples, the conduit has a separate wall enclosing the conduit, which can be mounted such that the conduit extends adjacent to the external flow path.

[0025] Then, the inner wall of the external flow path can have an outlet formed therein to introduce the air that bleeds out into the external flow path. In order to reduce the disturbance caused to the external flow, the conduit can be arranged to introduce the air that bleeds out in a substantially axial flow direction (that is, aligned with the flow in the external flow path). In this way, the conduit can make the bleed flow introduced into the external flow path basically aligned with the flow already in the external flow path, thereby reducing the disturbing effect of introducing the air flow. In the case where the conduit extends axially adjacent to the outer side cavity wall before arriving at the outlet leading to the core flow path, this can further help to align the bleed flow with the air flow direction of the external flow path. On the contrary, if the conduit is arranged to pass through the downstream cavity wall at a point away from the radially outer side cavity wall of the cavity, the conduit will need to redirect the bleed flow in a radially outward direction to reach the external flow path, and therefore the bleed flow will be introduced with a larger angle relative to the external flow, thereby causing additional disturbance to the external flow.

[0026] In some examples, the cavity is generally large annular, with circumferentially spaced struts or strut extensions disposed through the cavity for support. A plurality of conduits may be disposed between the struts / strut extensions, with each conduit providing a passage through the downstream cavity wall adjacent to the radially outer cavity wall of the cavity. Where a plurality of conduits are provided, the conduits may cover a majority of the angular range of the engine, and may be arranged, for example, over 60% or more of the angular range of the downstream cavity wall.

[0027] The positioning of the duct can be selected to avoid interference with components positioned in the external flow path. For example, the external flow path may include guide vanes to direct air through the external flow path. Additionally or alternatively, the external flow path may include one or more heat exchangers to take advantage of cooler air in the external flow path. Introducing bleed air into the external flow path may interfere with the directed air flow from the guide vanes and / or the operation of the heat exchanger because the bleed air from the core flow will typically be hotter than the air in the external flow path (e.g., the bypass channel). Thus, the duct can be arranged to introduce the bleed air into the external flow path at a location downstream of the guide vanes and / or the heat exchanger.

[0028] To further reduce the manufacturing complexity of the duct structure, the duct may be formed separately from the rest of the cavity and then installed within the gas turbine engine. For example, an opening may be machined in the downstream cavity wall, and the duct may be inserted into the cavity and placed against or inserted through the opening and then installed in place (e.g., by welding or bolting).

[0029] In some examples, surfaces of the duct and / or bleed passage are acoustically lined or otherwise provided with a surface designed to reduce noise generated by the engine.

[0030] Since the bleed air system can be selectively used based on engine operating conditions, an openable and closable bleed air valve can be provided to control the air flow from the core flow path to the external flow path. The bleed air valve can be located in the bleed air passage or in the conduit, for example covering an inlet to the bleed air passage, an outlet of the bleed air passage, an inlet of the conduit, and / or an outlet of the conduit.

[0031] From a second aspect, an intermediate compressor structure for a gas turbine engine is provided, the intermediate compressor structure comprising: a core flow path; and a cavity, the cavity being used to provide fluid communication between a bleed passage and a duct, the bleed passage being used to convey air from the core flow path to the cavity, and the duct being used to convey air from the cavity, the cavity having a downstream cavity wall; wherein the duct comprises a circumferentially extending opening, the circumferentially extending opening providing a passage for a radially outer cavity wall adjacent to the cavity through the downstream cavity wall.

[0032] From a third aspect, a method for manufacturing a gas turbine engine is provided, the method comprising: providing a core flow path and an outer flow path, the outer flow path being positioned at a greater radial displacement from the engine's axis of rotation than the core flow path; providing a cavity between the core flow path and the outer flow path, the cavity having a downstream cavity wall; forming an air bleed channel between the core flow path and the cavity; and forming a conduit between the cavity and the outer flow path; wherein forming the conduit comprises forming a circumferentially extending opening, the circumferentially extending opening providing a passage for a radially outer cavity wall adjacent to the cavity through the downstream cavity wall.

[0033] From a fourth aspect, a method for manufacturing a gas turbine engine is provided, the method comprising: providing a core flow path and an outer flow path, the outer flow path being positioned at a greater radial displacement from the engine's axis of rotation than the core flow path; providing a cavity between the core flow path and the outer flow path, the cavity having a downstream cavity wall; forming an air bleed passage between the core flow path and the cavity; inserting a conduit extending between the cavity and the outer flow path; and installing the conduit in the gas turbine engine; wherein the conduit includes a circumferentially extending opening and is installed to provide a passage for a radially outer cavity wall adjacent to the cavity through the downstream cavity wall.

[0034] Viewed from a fifth aspect there is provided a method of operating a gas turbine engine as described herein, the method comprising causing air to flow selectively from the core flow path into the cavity via the bleed air passage and from the cavity to the external flow path via the duct.

[0035] Optional features of the first aspect are also optional features of the second, third, fourth and fifth aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other aspects, features and advantages of the present invention will become apparent from the following description of examples which are to be read in conjunction with the accompanying drawings, in which:

[0037] Figure 1 shows a cross section of a gas turbine incorporating a duct according to an example embodiment;

[0038] FIG. 2A to FIG. 2C The arrangement of the conduits is shown in more detail;

[0039] Figure 3 Another cross section of the gas turbine engine taken along a different axis is shown;

[0040] Figure 4 shows an arrangement of catheters according to an alternative example embodiment;

[0041] Figure 5 is a flow chart illustrating a method of manufacturing a gas turbine engine; and

[0042] Figure 6 is a flow chart illustrating another method of manufacturing a gas turbine engine in which the ducts are separately manufactured and installed within the engine.

[0043] Any reference to prior art documents in this specification should not be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the art. As used in this specification, the words "include", "comprise" and similar words should not be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to". The present invention is further described with reference to the following examples. It should be understood that the claimed invention is not intended to be limited by these embodiments in any way. It will also be appreciated that the present invention encompasses not only individual embodiments, but also the combination of embodiments described herein.

[0044] The various embodiments described herein are presented only to help understand and teach the claimed features. These embodiments are provided only as representative examples of embodiments and are not exhaustive and / or exclusive. It should be understood that the advantages, embodiments, examples, functions, features, structures and / or other aspects described herein should not be considered as limitations on the scope of the invention defined by the claims or limitations on the equivalents of the claims, and other embodiments may be utilized and may be modified without departing from the spirit and scope of the claimed invention. In addition to those combinations specifically described herein, it is appropriate that various embodiments of the present invention may include appropriate combinations of disclosed elements, components, features, parts, steps, devices, etc., be composed of these appropriate combinations, or be substantially composed of these appropriate combinations. In addition, the present disclosure may include other inventions that are not currently claimed for protection but may be claimed for protection in the future.

[0045] In this application, the phrase "configured to" is used to indicate that an element of a device has a configuration capable of performing a defined operation. In this context, "configuration" means the arrangement or manner of interconnection of hardware or software. "Configured to" does not imply that the element of the device needs to be changed in any way in order to provide the defined operation. DETAILED DESCRIPTION

[0046] Figure 1 A cross section of a gas turbine engine 1 is shown incorporating a duct according to the invention, as described in detail below.

[0047] The skilled person will understand the main components of a gas turbine engine and its operation. In summary, the engine 1 comprises an air intake 2 which allows air to flow into the engine to a fan 3 located at the upstream end of the engine. All components are housed in a nacelle 4.

[0048] The engine includes a bypass passage 19 downstream of the fan and a central engine core, which contains a compressor, a burner and a turbine. The core of the engine is formed by a first low-pressure compressor 5 and a second high-pressure compressor 6. The multi-stage compressor arrangement brings air from ambient pressure and temperature to high temperature and high pressure. The compressed air is then delivered to the combustion chamber 7, where the fuel is injected and combustion occurs. It should be understood that this arrangement is only an example of how the engine can be arranged. In other examples, for example, the engine can have a geared fan or an open fan.

[0049] The combustion gases are exhausted from the rear of the combustion chamber 7 and first hit the high pressure turbine 10 and then the second low pressure turbine 12 before exiting the rear of the engine through the core nozzle 11. The thrust from the engine is generated by two air flows: the first air flow comes from the fan nozzle 8 (receiving thrust from the fan) and the second air flow comes from the exhaust of the core nozzle 11.

[0050] It should be understood that the airflow in the engine 1 is Figure 1 So, Figure 1 The rightward direction in can be referred to as the downstream direction of the engine 1, and Figure 1 The left direction in corresponds to the upstream direction of the engine.

[0051] The transition duct 14 is arranged to receive air from the low-pressure compressor 5 and convey it radially inwardly for supply to the high-pressure compressor 6 .

[0052] As shown, both compressors are coaxial with the central (rotational) axis of the turbine. The outer radius of the low-pressure compressor 5 (measured from the central axis of the compressor) is larger than the outer radius of the high-pressure compressor 6.

[0053] This requires that the duct or passage conveying the air between the two compressors be substantially S-shaped in order to convey the compressed air towards the central axis of the turbine and into the high-pressure turbine 6 .

[0054] It is desirable to be able to release or bleed some of the air within the transition duct to the outside of the engine. This can be used, for example, to control the volume of air delivered to the high pressure compressor and prevent the compressor from stalling.

[0055] like Figure 1 As shown, a bleed duct 15 is provided, which provides an openable passage that allows air to selectively flow from the transition duct 14 into a cavity 16 (in some embodiments, the cavity 16 may be referred to as a plenum or fire zone compartment). The cavity 16 may be arranged downstream of the low-pressure compressor 5. Specifically, the cavity 16 may be arranged radially outside the core, and the bleed passage is generally located downstream of the low-pressure compressor 5 and receives air released from the main flow path. In fact, the cavity 16 acts as a collection chamber or reservoir for air released from the main flow path.

[0056] The cavity is enclosed on the downstream side by a fire wall 17 (which may also be referred to as a downstream cavity wall). The fire wall 17 provides a boundary between the fire zones of the engine 1 to prevent leakage of combustible fluids between different sections of the engine 1. In order to allow the bleed air to escape from the cavity 16 into the bypass passage 19, a duct 18 is provided through the fire wall 17. The duct 18 may provide a passage through the fire wall 17 at the radial extreme point of the fire wall 17, so that the duct 18 may be considered to provide a passage above or outside the fire wall.

[0057] like Figure 1 As shown, the bleed air duct 15, cavity 16, and duct 18 provide a flow path to convey the bleed air between the core flow path and the bypass passage 19. In other embodiments, the bleed air may alternatively or additionally be conveyed from the core flow path to another flow path within the gas turbine engine 1, such as an intermediate flow path of a low-pressure core flow path that is radially farther from the axis of the engine 1 than the core flow path.

[0058] The arrangement of conduit 18 will be described in more detail with respect to the other figures.

[0059] Figure 2A The cavity 16 is shown and its relationship to the core flow path 22 and the outer flow path 24 (which may be, for example, Figure 1 2, a core flow path 22 for conveying the core flow A is provided. The axis of the engine 1 is located at Figure 2A, and thus the outer flow path 24 that carries the outer flow B is located further away from the axis of the engine 1 than the core flow path 22 .

[0060] To allow the bleed air flow C to escape the core flow path 22, there is a bleed passage 28 extending from the core flow path 22 into the cavity 16. The bleed passage 28 may be opened and closed using a bleed valve or bleed door that may be controlled to allow, prevent and / or control the amount of bleed air that leaves the core flow path 22.

[0061] The cavity 16, into which the bleed air is provided, is located radially between the core flow path 22 and the outer flow path 24. The downstream end of the cavity 16 is enclosed by a firewall 17. The firewall 17 is provided to separate the fire zones within the engine operating at different temperatures. Here, the firewall is located between the low-pressure compressor 5 and the high-pressure compressor 6, but it will be appreciated that the same technique can be applied more generally between compressor stages in the case of an engine having more than two compressors.

[0062] A conduit 18 provides a passage through the firewall 17. The conduit 18 is positioned so that it passes through an opening in the firewall 17. The conduit 18 is capable of directing the bleed air introduced into the bleed air flow C from the cavity 16 into the external flow path 24. The operating pressure of the core flow path 22 is higher than the operating pressure of the external flow path 24, so that, in use, air introduced into the cavity 16 will naturally flow out from the cavity 16 through the conduit 18 as flow D into the external flow path 24.

[0063] Although according to one approach the conduit may be positioned in the firewall 17 away from the outer edge of the cavity 16, such as near the core flow path 22 or midway between the core flow path 22 and the outer flow path 24, according to the arrangement described herein the conduit 18 is arranged such that the conduit 18 passes through the firewall 17 at a position adjacent to the outer cavity wall of the cavity 16 (i.e., the wall formed by the inner surface of the outer flow path 24).

[0064] like Figure 2A As shown, the conduit 18 is positioned against the outer flow path and is separated by the wall 38, so that the wall 38 of the outer flow path 24 encloses one side of the conduit 18 and the conduit extends along the side of the outer flow path 24. However, it should be understood that in other embodiments, the conduit 18 may not be positioned adjacent to the radially outer cavity wall of the cavity 16, but more generally, it may be positioned at the radial end of the firewall 17. In this case, the conduit 18 can be positioned so that a high aspect ratio between the circumferential width and the radial height can be adopted. For example, an aspect ratio of 2.5:1, 3:1, 4:1 or 5:1 can be used.

[0065] The duct is positioned so that it provides access through the firewall 17 adjacent the radially outer wall of the cavity, which reduces the space occupied by the duct 18 at the most crowded areas in the firewall 17 and simplifies the routing of the duct to the external flow path 24. In addition, the height of the duct 18 in the radial direction can be reduced when placed adjacent the radially outer wall of the cavity 16 because the circumferential extent of the duct 18 can be increased to provide the required air flow. Positioning components in the firewall 17 can be particularly challenging because various components may need to be integrated with each other here. Thus, by positioning the duct 18 in this manner, the integration of components on the firewall 17 can be simplified.

[0066] exist Figure 2A In the example embodiment shown, an inlet 30 of the duct 18 is provided in the firewall 17, and an outlet 34 of the duct 18 for releasing air into the external flow path 24 is provided in the inner wall of the external flow path 24. The inlet 30 may be provided as part of the firewall 17, or may be located outside the outer edge of the firewall 17.

[0067] The conduit 18 extends substantially parallel to the external flow path 24 before reaching the outlet 34. By positioning the conduit at the outer edge of the cavity 16 and extending the conduit 18 along the external flow path 24 in this manner, when air is introduced into the external flow path 24, the air flow E is oriented substantially parallel to the external air flow B, which reduces interference with the external air flow when the bled air is introduced.

[0068] The external flow path 24 carries cooler air than the core flow path 22, so the cooler air can be used to cool components of the engine. For example, in the case where the gas turbine engine 1 utilizes a reduction gearbox, a large amount of heat can be dissipated even if the efficiency of the gearbox is high. In order to cool the gearbox, the cold air in the bypass channel of the engine 1 can be used to remove and control the heat. This allows the gearbox to be conveniently cooled. To this end, a heat exchanger (not shown) can be positioned in the external flow path 24 (which can be a bypass channel) to dissipate heat into the external flow path 24 (e.g., heat from the reduction gearbox).

[0069] Where such a heat exchanger is provided, the outlet 34 of the conduit 18 is positioned downstream of the heat exchanger to prevent the hotter bleed air from the core flow path 22 from interacting with the heat exchanger and potentially reducing the efficiency of heat removal from the heat exchanger.

[0070] Similarly, where the external flow path 24 includes guide vanes to manipulate air flow, the outlet 34 may be positioned to introduce bleed air into the external flow path 24 downstream of the guide vanes to avoid interfering with the operation of the guide vanes.

[0071] In some examples, the surfaces of bleed air duct 15 and / or duct 18 are provided with an acoustic lining and / or acoustic surface configured to reduce engine noise.

[0072] Figure 2A Also depicted in FIG. 2 are struts 36 disposed in the core flow path 22 and the outer flow path. The strut extensions may be used to form a load path between the inner struts and the outer struts. Guide vanes 37 are also disposed in the core flow path 22 to remove vortices in the core air flow before the core air flow enters the core flow path. Thus, in this example, the bleed passage 28 is positioned between the struts in the core flow path 22 and their strut extensions. In some examples, other components such as a heat exchanger and / or a stator may be disposed in the outer flow path 24.

[0073] Figure 2B The flow path 24 from the outside is shown along Figure 2A Another view of the catheter 18 viewed from the direction E indicated in FIG. Figure 2B As shown, the external flow path 24 extends from left to right in the downstream direction, wherein the duct 18 shown in phantom extends below the external flow path 24 and directs the air flow D along the duct 18 and out of the outlet 34 to introduce the bleed air into the external flow path 24 as the air flow E. That is, the purge door can be opened or closed to prevent air from flowing through the outlet 34. In some examples, the purge door or purge valve can be alternatively or additionally positioned in the purge duct 28.

[0074] like Figure 2B As shown, the conduit 18 has a purge valve that can be opened or closed to allow or prevent the purge air from flowing into the external flow path 24 .

[0075] Figure 2C Shown along Figure 2B Another view of the catheter 18 viewed from the direction F is shown. Figure 2C 1 shows a view along the length of the conduit 18 in the direction of air flow. Figure 2C As shown, there is an inlet 30. The inlet 30 is arranged in the fire wall 17 of the cavity 16, and is located adjacent to the outer wall of the cavity to form a passage / opening in the fire wall 17 adjacent to the outer wall of the cavity.

[0076] To separate the conduit 18 from the external flow path 24, a wall 38 is present, such as Figure 2Cshown.

[0077] Figure 3 Shown along Figure 2A Another cross section of the gas turbine engine taken along line GG shown in FIG. Figure 3 The core flow path 22 and the outer flow path 24 are shown separated by a cavity 16 with a firewall 17 at the downstream end of the cavity 16. Struts 44 positioned at angular intervals around the gas turbine engine 1 serve to support the structure of the engine 1 .

[0078] Several bleed air passages and ducts 18 are arranged between these struts / strut extensions 44, and the ducts 18 together may extend circumferentially around more than 60% of the annular space of the engine 1. Figure 3 As can be seen in the , the openings of the ducts in the firewall 17 extend circumferentially around the firewall 17, forming a diamond shape. Despite occupying a large circumferential width, the ducts 18 can be arranged with a high aspect ratio so that they only cover a small radial height. In some examples, an aspect ratio of circumferential width to radial height greater than 2.5 is used. This reduced radial height can be achieved by positioning the ducts 18 adjacent to the outer cavity wall of the cavity 16 (i.e., adjacent to the wall 38 that encloses the external flow path 24), while still providing sufficient cross-sectional area to guide the vented air. In addition, by placing the ducts 18 in this manner, a larger flow area can be achieved if desired because it is easier to accommodate a larger area of ​​the duct 18 in this location than would be possible if the ducts 18 were located elsewhere in the firewall 17.

[0079] Figure 4 A cross section of a cavity 16 of an engine 1 according to another example embodiment is shown. Figure 4 The corresponding Figure 2A Components of similar components will no longer be referenced Figure 4 Discuss in detail.

[0080] according to Figure 4 However, the conduit 18 now extends into the cavity 16 so that the inlet 40 protrudes from the fire wall 17. The conduit 18 is still arranged to provide a passage through the fire wall 17 (or a portion of the fire wall 17) adjacent to the wall 38 enclosing the external flow path 24, wherein the conduit 18 extends through an opening formed at the edge of the fire wall 17.

[0081] Inlet 40 is aligned using mounting 42 to receive bleed air flow C from bleed passage 28 as air flow D'. To this end, inlet 40 is positioned opposite the outlet of bleed passage 28 in cavity 16 to improve air flow efficiency between bleed passage 28 and conduit 18.

[0082] Directing the air flow in this manner may also improve particle extraction and water ejection from the cavity 16 , thereby preventing particle / water accumulation in the cavity 16 .

[0083] Figure 5 is a flow chart illustrating a method of assembling a gas turbine engine 1. At step 52, core flow path 22 and outer flow path 24 (which may be, for example, a bypass passage) are arranged such that outer flow path 24 is positioned at a greater radial displacement from the engine axis than core flow path 24.

[0084] At step 54 , a cavity 16 having a downstream cavity wall, such as a firewall 17 , is disposed between the core flow path 22 and the outer flow path 24 , and at step 56 , a bleed passage 28 is formed between the core flow path 22 and the cavity 16 , and the bleed passage 28 is configured to convey bleed air from the core flow path 22 into the cavity 16 .

[0085] Then, at step 58, a conduit 18 is formed between the cavity 16 and the external flow path 24 to convey air from the cavity 16 to the external flow path 24. The conduit 18 is formed to provide a passage through a circumferentially extending opening in the downstream cavity wall adjacent the radially outer cavity wall of the cavity 16.

[0086] Figure 6 is a flow chart illustrating another method of assembling a gas turbine engine 1 as described herein, in which the duct 18 is separately manufactured and installed within the engine 1 . Figure 6 Steps 62 to 66 correspond to Figure 5 Steps 52 to 56 of the present invention are described below and therefore will not be discussed in detail here.

[0087] However, in this method, the duct 18 can be manufactured separately and inserted into the gas turbine engine 1 at step 68 so as to extend between the cavity 16 and the external flow path 24. Then, the duct 18 is installed at step 70 and is positioned adjacent to the radially outer cavity wall of the cavity 16 to provide a passage through the circumferentially extending opening in the downstream cavity wall. The duct 18 can be, for example, welded or bolted to a suitable position on the downstream cavity wall. Due to its position on the firewall, as described above, more space can be used for welding lines and / or bolt joints than if the duct 18 is located elsewhere, thereby simplifying this step of installing the duct 18.

[0088] Thus, there has been described an arrangement of ducting for a bleed air system for a gas turbine engine that can free up space within the engine for other equipment and functions, and that enables easier manufacturing and less intrusive introduction of air into an external flow path.

Claims

1. A gas turbine engine, comprising: a core flow path and an outer flow path, the outer flow path being positioned at a greater radial displacement from an axis of rotation of the engine than the core flow path; as well as a cavity for providing fluid communication between a bleed passage for conveying air from the core flow path to the cavity and a conduit for conveying air from the cavity to the outer flow path, the cavity having a downstream cavity wall; Wherein, the conduit includes a circumferentially extending opening, and the circumferentially extending opening provides a passage for a radially outer cavity wall adjacent to the cavity through the downstream cavity wall.

2. The gas turbine engine according to claim 1, wherein: The circumferential width of the circumferentially extending opening is greater than its height in the radial direction.

3. The gas turbine engine according to claim 1 or 2, wherein: The circumferentially extending opening has an aspect ratio of a circumferential width to a radial height greater than 3:1, optionally greater than 4:1, and optionally greater than 5:

1.

4. A gas turbine engine according to any one of the preceding claims, wherein: The conduit extends adjacent to a radial inner wall of the outer flow path in the direction of air flow such that the inner wall of the outer flow path at least partially encloses the conduit, and wherein the conduit intersects the inner wall of the outer flow path to provide an outlet into the outer flow path.

5. A gas turbine engine according to any one of the preceding claims, wherein: The inner wall of the outer flow path separates the cavity and the outer flow path, and the conduit includes an outlet formed in the inner wall of the outer flow path for providing air to the outer flow path.

6. A gas turbine engine according to any one of the preceding claims, wherein: The conduit extends axially adjacent the outer cavity wall, and wherein the conduit is arranged to introduce air into the outer flow path in a substantially axial flow direction.

7. A gas turbine engine according to any one of the preceding claims, wherein: The conduit includes an inlet for receiving air from the cavity, the inlet being formed in the downstream cavity wall adjacent the radially outer cavity wall of the cavity.

8. The gas turbine engine according to claim 7, wherein: The inlet is positioned against the outer wall of the cavity such that the outer wall forms an edge of the inlet.

9. The gas turbine engine according to any one of claims 1 to 6, wherein: The conduit includes an inlet for receiving air from the cavity, the inlet being formed in the cavity, wherein the conduit extends from the circumferentially extending opening into the cavity.

10. The gas turbine engine according to claim 9, wherein: The inlet is oriented to be substantially aligned with the outlet of the deflation passage.

11. A gas turbine engine according to any one of the preceding claims, wherein: The bleed passage is arranged to redirect air from a first flow direction to a second flow direction, wherein the air in the core flow path has the first flow direction; and The duct is arranged to redirect air from the second flow direction to a third flow direction substantially parallel to the first flow direction.

12. The gas turbine engine according to any one of claims 9 to 11, wherein: The ducts are arranged to redirect the air at an angle between 15° and 90°.

13. A gas turbine engine according to any one of the preceding claims, wherein: The engine includes a plurality of circumferentially spaced struts and / or strut extensions and a plurality of ducts for conveying air from the cavity to the external flow path, wherein each duct provides a passage through the downstream cavity wall adjacent to the outer cavity wall and between adjacent struts and / or strut extensions.

14. A gas turbine engine according to any one of the preceding claims, comprising a plurality of ducts, wherein each duct comprises a circumferentially extending opening providing a respective passage adjacent the outer cavity wall of the cavity through the downstream cavity wall, and wherein, The respective passages are arranged together over more than 60% of the angular extent of the downstream chamber wall.

15. A gas turbine engine according to any one of the preceding claims, comprising one or more heat exchangers positioned in the external flow path, wherein: The conduit is arranged to introduce air into the external flow path downstream of the one or more heat exchangers.

16. A gas turbine engine according to any one of the preceding claims, wherein: The duct is formed separately from the cavity and is mounted within the gas turbine engine.

17. A gas turbine engine according to any one of the preceding claims, comprising one or more guide vanes positioned in the outer flow path, wherein: The duct is arranged to introduce air into the outer flow path downstream of the one or more guide vanes.

18. A gas turbine engine according to any one of the preceding claims, wherein: The surface of the deflation channel and / or the conduit comprises an acoustic lining.

19. A gas turbine engine according to any one of the preceding claims, wherein: The conduit includes a purge valve operable to control air flow into the external flow path.

20. A gas turbine engine according to any one of the preceding claims, wherein: The external flow path is a bypass flow path.

21. The gas turbine engine according to any one of claims 1 to 19, wherein: The outer flow path is an intermediate flow path or a low pressure core flow path.

22. A gas turbine engine according to any one of the preceding claims, wherein: The bleed air passage is positioned at a compressor stage of the gas turbine engine.

23. An intermediate compressor structure for a gas turbine engine, the intermediate compressor structure comprising: core flow path; as well as a cavity for providing fluid communication from a bleed passage to a conduit, the bleed passage for conveying air from the core flow path to the cavity, and the conduit for conveying air from the cavity, the cavity having a downstream cavity wall; Wherein, the conduit includes a circumferentially extending opening, and the circumferentially extending opening provides a passage for a radially outer cavity wall adjacent to the cavity through the downstream cavity wall.

24. A method comprising: providing a core flow path and an outer flow path, the outer flow path being positioned at a greater radial displacement from an axis of rotation of a gas turbine engine than the core flow path; providing a cavity between the core flow path and the outer flow path, the cavity having a downstream cavity wall; forming a venting passage between the core flow path and the cavity; as well as forming a conduit between the cavity and the external flow path; Wherein forming the conduit includes forming a circumferentially extending opening, the circumferentially extending opening providing a passageway adjacent a radially outer cavity wall of the cavity through the downstream cavity wall.

25. A method comprising: providing a core flow path and an outer flow path, the outer flow path being positioned at a greater radial displacement from an axis of rotation of a gas turbine engine than the core flow path; providing a cavity between the core flow path and the outer flow path, the cavity having a downstream cavity wall; forming a venting passage between the core flow path and the cavity; a conduit inserted to extend between the cavity and the external flow path; as well as installing the duct within the gas turbine engine; Wherein, the conduit includes a circumferentially extending opening and is arranged to provide a passageway for a radially outer cavity wall adjacent to the cavity through the downstream cavity wall.

26. A method of operating a gas turbine engine according to any one of claims 1 to 22, the method comprising: Air is selectively caused to flow from the core flow path into the cavity via the bleed passage, and from the cavity to the external flow path via the conduit.

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