Adjustable bleed air mechanism of bleed air high-pressure turbine of aero-engine combustion chamber

Abstract

The invention provides an adjustable air entraining mechanism of an air entraining high-pressure turbine of an aero-engine combustion chamber. The adjustable air entraining mechanism comprises an adjustable air entraining assembly arranged at an inlet of the combustion chamber and an adjusting assembly arranged on the rear portion of the combustion chamber and located outside a casing. The adjustable air entraining assembly comprises an air entraining pipe unit, the air entraining pipe unit comprises an outer-layer grating and an inner-layer grating which are coaxially arranged in a sleeving mode, first air holes are annularly formed in the pipe wall of the outer-layer grating, second air holes are annularly formed in the same position of the pipe wall of the inner-layer grating, and the first air holes and the second air holes are used for entraining air; the inner-layer grille is driven by an adjusting assembly to rotate around the axis relative to the outer-layer grille; the inner-layer grating rotates to change the overlapping area of the second air holes and the first air holes so as to adjust the effective circulation area of the air entraining holes; the second air holes comprise third air holes, and the third air holes are larger than the first air holes; and when the inner-layer grating rotates until the other second air holes except the third air holes are staggered with the corresponding first air holes, the third air holes are overlapped or partially overlapped with the corresponding first air holes.

Description

Technical Field

[0001] This application relates to the technical field of bleed air design for aero-engine combustors, and more particularly to an adjustable bleed air mechanism for a high-pressure turbine for bleed air in aero-engine combustors. Background Technology

[0002] With the rapid development of aviation technology, advanced aero engines, as the main power source for aircraft and other aircraft, are evolving towards higher thrust-to-weight ratios, higher reliability, environmental friendliness, and longer service life. Among the core components of aero engines, the design of the combustion chamber and turbine is crucial to engine performance and efficiency. High-pressure turbines, in particular, operate in harsh environments, subjected to high temperatures and high-speed gas impacts, requiring effective cooling systems to ensure their normal operation.

[0003] Traditional high-pressure turbine cooling air circuits typically use fixed orifice plates or simple on / off valves for flow control. Fixed orifice plates cannot adjust the cooling air volume according to different engine operating conditions. For example, during subsonic cruise, the turbine temperature is low, and the cooling demand is small; while during takeoff, the turbine temperature is highest, and the cooling demand is greatest. This inability to flexibly adjust the cooling air volume according to actual operating conditions results in either insufficient cooling air volume under non-design conditions, affecting turbine life, or excessive cooling air volume, wasting high-pressure air and reducing engine efficiency.

[0004] Existing adjustable valves (such as butterfly valves and ball valves) face the following problems when applied to the high-temperature, high-pressure, and space-constrained bleed air environment of aero-engine combustion chambers: 1) Limited adjustment range, making it difficult to achieve precise linear or near-linear adjustment across the entire flow range from small to large flow rates; 2) High-temperature jamming / failure, if the valve actuation mechanism (such as motor or connecting rod) is located in a high-temperature area (near the combustion chamber or turbine), it is prone to material performance degradation, lubrication failure, and thermal expansion jamming due to high temperatures, resulting in poor reliability; 3) Complex and bulky structure, in order to withstand high temperatures and pressures, valves and drive mechanisms are often designed to be relatively thick and heavy, increasing the engine weight and space.

[0005] Therefore, developing a high-pressure turbine adjustable bleed air mechanism that can flexibly adjust the cooling airflow over a wide range to meet the requirements of the engine under all operating conditions, while also taking into account compact and lightweight design, has become an important research direction in the field of aero-engine combustor bleed air design. Summary of the Invention

[0006] To address the aforementioned practical problems and the shortcomings of existing technologies, the main technical problem this invention aims to solve is to provide an adjustable bleed air mechanism for the high-pressure turbine of an aero-engine combustion chamber. Its core objective is to achieve wide-range, continuous, and precise adjustment of the volume of high-pressure air drawn from the combustion chamber inlet to the high-pressure turbine for cooling, thus adapting to the engine's requirements under all operating conditions. This significantly improves the reliability and service life of the mechanism in high-temperature environments, prevents actuator failure or jamming due to high temperatures, optimizes the structural layout, and strives for a compact and lightweight mechanism to meet the stringent space constraints of aero-engines.

[0007] To solve the above-mentioned technical problems, this application provides an adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine, adopting the following technical solution:

[0008] An adjustable bleed air mechanism for a high-pressure turbine for bleed air in the combustion chamber of an aero-engine includes an adjustable bleed air assembly disposed at the inlet of the combustion chamber and an adjustment assembly disposed at the rear of the combustion chamber and outside the casing.

[0009] The adjustable air intake assembly includes multiple air intake pipe units evenly distributed circumferentially along the combustion chamber inlet. Each air intake pipe unit is a double-layer grid structure. The air intake pipe unit includes an outer grid and an inner grid arranged coaxially. The outer grid is sleeved outside the inner grid.

[0010] The outer grid has a plurality of first air holes on its tube wall, and the inner grid has a plurality of second air holes on its tube wall at the same position. The second air holes are arranged in a one-to-one correspondence with the first air holes. The size of the second air holes is adapted to the size of the first air holes. The first air holes and the second air holes are used to draw air.

[0011] The air intake pipe unit draws air into the high-pressure turbine region through the cooling air passage; the inner grid has an internal airflow passage that communicates with the second air hole, and the airflow passage is connected to the cooling air passage.

[0012] The inner grid is a rotating component, driven by the adjustment assembly to rotate relative to the outer grid around an axis; the rotation of the inner grid changes the overlapping area of ​​the second air hole and the first air hole, thereby adjusting the effective flow area of ​​the air intake air hole.

[0013] The plurality of second air holes includes at least one third air hole, the third air hole being larger than the first air hole; when the inner layer grid rotates to the point where the other second air holes, excluding the third air hole, are misaligned with the corresponding first air holes, the third air hole coincides with or partially coincides with its corresponding first air hole.

[0014] In a preferred embodiment, the first vent, the second vent, and the third vent are all square holes; the length of the third vent along the circumferential direction is greater than the length of the first vent.

[0015] In a preferred embodiment, the third air hole is arranged parallel to the direction of airflow, and the third air hole is disposed on the inner layer grid near the tube wall of the flame tube in the combustion chamber.

[0016] In a preferred embodiment, the annular gap between the outer grid and the inner grid is sealed by an inner sealing ring.

[0017] In a preferred embodiment, a cover plate is fixedly provided at the end of the tube of the outer grille, the cover plate is fixedly connected to the outer casing of the combustion chamber, and the outer grille is fixed to the outer casing;

[0018] An outer sealing ring is provided at the mating surface between the cover plate and the outer casing.

[0019] In a preferred embodiment, the adjustment component includes a drive component, a linkage component, and multiple sets of transmission components, with one set of transmission components connected to one of the air duct units;

[0020] The rotating shaft of the inner grille extends out of the outer grille and is connected to the transmission assembly. Multiple sets of the transmission assemblies are connected to a linkage member, which is driven by the driving member to synchronously drive all the inner grilles to rotate.

[0021] In a preferred embodiment, the linkage is a ring structure, and the linkage is arranged around the outside of the combustion chamber casing; multiple sets of the transmission components are evenly distributed circumferentially and are connected to the linkage for transmission.

[0022] In a preferred embodiment, the transmission assembly includes a rocker arm and a connecting rod; each end of the connecting rod is provided with a universal joint, one end of which is rotatably connected to the rocker arm via the universal joint, and the other end of which is rotatably connected to the linkage via the universal joint.

[0023] The end of the rocker arm away from the connecting rod is connected to the pivot of the inner grid.

[0024] In a preferred embodiment, the drive unit includes at least two drive motors that are evenly distributed circumferentially outside the rear casing of the combustion chamber, and the output terminals of the multiple sets of drive motors are connected to the linkage.

[0025] The drive motor drives the linkage to move axially, and the movement is converted into rotation of the inner grille through the transmission assembly.

[0026] In summary, this application has the following beneficial effects:

[0027] 1. Achieves precise adjustment across a wide range of operating conditions: This invention continuously changes the effective flow area of ​​the airflow channel by rotating the adjustable grille inside the air intake pipe. It also employs a specific large-area hole design on the inner grille to ensure the minimum cooling flow required for idle conditions even at the minimum opening, while meeting the maximum flow requirements for high-power conditions such as takeoff at the maximum opening. A single mechanism can achieve a large adjustment ratio of cooling air volume and realize linear and precise continuous control across the entire range, enabling the cooling air supply to match the engine operating conditions in real time, effectively improving fuel economy and turbine life.

[0028] 2. A highly compact and lightweight integrated structure is adopted: This invention features a zoned layout for drive and adjustment functions, with precision components such as stepper motors installed in the low-temperature zone of the outer casing, avoiding the influence of high-temperature environments. The adjustable grille is directly integrated inside the air intake pipe, replacing the traditional external valve body and complex flow channels. Simultaneously, a single linkage ring centrally drives all circumferential adjustment units within the narrow space of the combustion chamber, resulting in a simple transmission chain. This design significantly reduces the system's size, weight, and complexity, and helps minimize the impact on the main airflow resistance.

[0029] 3. Significantly improved system reliability and lifespan in high-temperature environments: Based on the above-mentioned partitioned and integrated design, only a few simple moving parts such as grille shafts are retained in the high-temperature area, reducing the risk of jamming; the universal joint in the transmission mechanism effectively absorbs thermal deformation stress, and the material properties, lubrication status and motion accuracy of the drive components are guaranteed when working in low-temperature environments, thereby enhancing the overall reliability, response speed and service life of the system in the harsh environment of the engine. Attached Figure Description

[0030] Figure 1 This is a schematic diagram showing the axial position of the combustion chamber and the adjustable bleed air mechanism inside the aircraft engine in this embodiment;

[0031] Figure 2 This is a schematic diagram of the circumferential position of the air intake pipe unit at the inlet section of the combustion chamber in this embodiment;

[0032] Figure 3 This is a schematic diagram of the transmission structure of a single air venting tube unit and transmission assembly in this embodiment;

[0033] Figure 4 This is a cross-sectional view of a single air intake tube unit in this embodiment;

[0034] Figure 5 This embodiment presents a schematic diagram of the cross-sectional area of ​​a single air intake tube unit's vent (wherein, Figure 5 'a' is a schematic diagram of the maximum flow state. Figure 5 b is the minimum flow state diagram.

[0035] Explanation of reference numerals in the attached drawings: 1. Outer casing; 2. Inner casing; 3. Diffuser; 4. Flame tube; 5. Bushing; 6. High-pressure turbine guide vane; 7. High-pressure turbine moving blade; 8. Outer grid; 9. Cooling air passage; 10. Rocker arm; 11. First universal joint; 12. Connecting rod; 13. Second universal joint; 14. Linkage component; 15. Drive motor; 16. Fixing screw; 17. Cover plate; 18. Outer sealing ring; 19. Connecting screw; 20. Inner sealing ring; 21. Inner grid; 22. Motor connection clip; 23. Air intake pipe unit; 24. First air port; 25. Second air port; 26. Third air port. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed", "equipped", "sleeved / connected", "connected", etc., should be interpreted broadly. For example, "connection" can be a wall-mounted connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0039] The following is in conjunction with the appendix Figures 1-5 This application will be described in further detail.

[0040] This embodiment provides an adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine, with reference to... Figure 1The combustion chamber includes an outer casing 1, an inner casing 2, and a flame tube 4, which is located within the space enclosed by the outer casing 1 and the inner casing 2. The adjustable bleed air mechanism includes an adjustable bleed air assembly located at the inlet of the combustion chamber and an adjustment assembly located at the rear of the combustion chamber and outside the casing.

[0041] refer to Figure 2 The adjustable air intake assembly includes multiple air intake pipe units 23 evenly distributed circumferentially along the combustion chamber inlet. Each air intake pipe unit 23 is a double-layer grid structure. The air intake pipe unit 23 includes an outer grid 8 and an inner grid 21 arranged coaxially. The outer grid 8 is sleeved outside the inner grid 21.

[0042] The outer grid 8 has a plurality of first air holes 24 arranged in a ring on its tube wall, and the inner grid 21 has a plurality of second air holes 25 arranged in a ring at the same position on its tube wall. The second air holes 25 are arranged in a one-to-one correspondence with the first air holes 24. The second air holes 25 are adapted to the size of the first air holes 24 and are slightly larger than the first air holes 24. The first air holes 24 and the second air holes 25 are used for air intake.

[0043] The air intake pipe unit 23 draws air to the high-pressure turbine region through the cooling air passage 9, which is located between the combustion chamber bushing 5 and the inner casing 2; the inner grille 21 has an internal airflow passage that communicates with the second air hole 25, and the airflow passage is connected to the cooling air passage 9.

[0044] After passing through the diffuser 3, part of the airflow enters the combustion chamber, and the other part enters the cooling air passage 9 through the adjustable bleed air assembly and acts on the high-pressure turbine region. The high-pressure turbine region includes the high-pressure turbine guide vane 6 and the high-pressure turbine moving blade 7. The high-pressure cooling air at the combustion chamber inlet is guided through the cooling air passage 9 to the high-pressure turbine guide vane 6 and the high-pressure turbine moving blade 7 for cooling by the bleed air pipe unit 23.

[0045] refer to Figure 4 Each air intake tube unit 23 has a double-layer grid structure, including an outer grid 8 as a fixed component and an inner grid 21 as a rotating component.

[0046] The outer grille 8 has a cover plate 17 fixedly attached to its end. The cover plate 17 is fixedly connected to the outer casing 1 of the combustion chamber. The cover plate 17 and the outer casing 1 are fastened together by fixing screws 16, so that the outer grille 8 is fixed to the outer casing 1. An outer sealing ring 18 is provided at the mating surface between the cover plate 17 and the outer casing 1 to prevent gas leakage.

[0047] refer to Figure 5Eight square holes of equal shape and area are evenly distributed circumferentially on the wall of the outer grid 8, serving as first air holes 24 and acting as basic airflow channels. The inner grid 21 is a rotating component, coaxially sleeved inside the outer grid 8, and the annular gap between the outer grid 8 and the inner grid 21 is sealed by an inner sealing ring 20. Eight square holes are evenly distributed circumferentially on the corresponding positions of the inner grid 21, serving as second air holes 25. The inner grid 21 is driven by the adjusting component to rotate relative to the outer grid 8 around its axis; the rotation of the inner grid 21 changes the overlapping area of ​​the second air holes 25 and the first air holes 24, thereby adjusting the effective flow area of ​​the air intake holes.

[0048] Of the eight second air holes 25, the one parallel to the airflow direction and closest to the flame tube 4 in the combustion chamber is designed to have the largest area. This largest second air hole 25 forms a third air hole 26, which is larger than the first air hole 24, and its circumferential length is greater than that of the first air hole 24. When the inner grille 21 rotates until the other second air holes 25 (excluding the third air hole 26) are misaligned with their corresponding first air holes 24, the third air hole 26 coincides with or partially coincides with its corresponding first air hole 24. This ensures that when all second air holes 25 are closed with the first air holes 24, the third air hole 26 maintains airflow with the first air holes 24, ensuring minimum flow and guaranteeing that the bleed airflow at the minimum effective flow area meets the engine's idle flow requirements.

[0049] refer to Figure 2 The adjustment assembly includes a drive component, a linkage component 14, and nine sets of transmission components. Each set of transmission components is connected to one of the air intake pipe units 23. The rotating shaft of the inner grille 21 extends from the outer grille 8 and is connected to the transmission components. The nine sets of transmission components are all connected to the linkage component 14, which is driven by the drive component to synchronously drive all the inner grilles 21 to rotate. The linkage component 14 has a ring structure and is arranged around the outside of the combustion chamber casing. The nine sets of transmission components are evenly distributed circumferentially and are connected to the linkage component 14 for transmission.

[0050] refer to Figure 3 The transmission assembly includes a rocker arm 10 and a connecting rod 12; the two ends of the connecting rod 12 are respectively provided with a first universal joint 11 and a second universal joint 13, one end of which is rotatably connected to the rocker arm 10 through the first universal joint 11, and the other end of which is rotatably connected to the linkage 14 through the second universal joint 13; the end of the rocker arm 10 away from the connecting rod 12 is connected to the rotating shaft of the inner grille 21 through a connecting screw 19.

[0051] The drive unit includes three drive motors 15 evenly distributed circumferentially outside the rear casing of the combustion chamber. These drive motors 15 are high-precision, high-temperature resistant stepper motors. Each drive motor 15 is fixed to the outer casing 1 of the combustion chamber via a bracket, providing support and stability. The drive motors 15 do not directly contact the outer casing 1, thus reducing their operating temperature. The output ends of the three sets of drive motors 15 are connected to the linkage 14 via motor connection clips 22. The drive motors 15 drive the linkage 14 to move axially, which is then converted into rotation of the inner grille 21 via a transmission assembly.

[0052] The working principle and adjustment process of the adjustable bleed air mechanism are as follows:

[0053] The engine control system calculates the required cooling air volume based on real-time operating conditions and sends commands to the three drive motors 15. The drive motors 15 operate synchronously, and the linear motion of their output shafts drives the linkage 14 to move axially through the motor connection buckle 22.

[0054] The axial movement of the linkage 14 is synchronously converted into the rotational movement of the inner grid 21 of the nine identical transmission components. The rotation of the inner grid 21 changes the overlapping area between the second air hole 25 on it and the first air hole 24 on the fixed outer grid 8, thereby realizing continuous flow regulation.

[0055] Maximum flow status: such as Figure 5 As shown in (a), when the inner grille 21 rotates until all its second air holes 25 and third air holes 26 completely overlap with the first air hole 24 of the outer grille 8, all eight airflow channels of each air intake unit 23 are fully opened, maximizing the flow area and providing the maximum cooling air volume for the engine in high power mode (takeoff).

[0056] Minimum flow state: such as Figure 5 As shown in (b), when the inner grille 21 is rotated to a specific angle, causing most of the vents to be offset, seven of the eight second vents 25 are completely blocked. However, due to the design of the large-area third vent 26 on the inner grille 21 near the flame tube 4, at this position, this third vent 26 still partially overlaps with the first vent 24 of the outer grille 8, forming a minimum effective flow channel. This minimum flow area is precisely designed to accurately meet the minimum cooling flow required by the engine at idle.

[0057] Continuous adjustment mode: Between the two extreme positions mentioned above, by controlling the precise stroke of the drive motor 15, the inner grille 21 can be stopped at any intermediate angle, thereby achieving continuous and stepless adjustment of the effective airflow area from minimum to maximum. This allows the cooling air volume to be matched with the engine's needs in real time and with precision under various cruise, acceleration, and deceleration transition conditions.

[0058] The above description is merely a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention by those skilled in the art within the scope of the technology disclosed in the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. An adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine, characterized in that: It includes an adjustable bleed air assembly located at the inlet of the combustion chamber and an adjustment assembly located at the rear of the combustion chamber and outside the casing; The adjustable air intake assembly includes multiple air intake pipe units evenly distributed circumferentially along the combustion chamber inlet. Each air intake pipe unit is a double-layer grid structure. The air intake pipe unit includes an outer grid and an inner grid arranged coaxially. The outer grid is sleeved outside the inner grid. The outer grid has a plurality of first air holes on its tube wall, and the inner grid has a plurality of second air holes on its tube wall at the same position. The second air holes are arranged in a one-to-one correspondence with the first air holes. The size of the second air holes is adapted to the size of the first air holes. The first air holes and the second air holes are used to draw air. The air intake pipe unit draws air into the high-pressure turbine region through the cooling air passage; the inner grid has an internal airflow passage that communicates with the second air hole, and the airflow passage is connected to the cooling air passage. The inner grid is a rotating component, driven by the adjustment assembly to rotate relative to the outer grid around an axis; the rotation of the inner grid changes the overlapping area of ​​the second air hole and the first air hole, thereby adjusting the effective flow area of ​​the air intake air hole. The plurality of second air holes includes at least one third air hole, the third air hole being larger than the first air hole; when the inner layer grid rotates to the point where the other second air holes, excluding the third air hole, are misaligned with the corresponding first air holes, the third air hole coincides with or partially coincides with its corresponding first air hole.

2. The adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine according to claim 1, characterized in that: The first, second, and third vents are all square holes; the length of the third vent along the circumferential direction is greater than the length of the first vent.

3. The adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine according to claim 1, characterized in that: The third air hole is arranged parallel to the direction of airflow and is located on the inner grid near the wall of the flame tube in the combustion chamber.

4. The adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine according to claim 1, characterized in that: The annular gap between the outer grid and the inner grid is sealed by the inner sealing ring.

5. The adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine according to claim 1, characterized in that: The outer grille has a cover plate fixed to its tube end, and the cover plate is fixedly connected to the outer casing of the combustion chamber. The outer grille is fixed to the outer casing. An outer sealing ring is provided at the mating surface between the cover plate and the outer casing.

6. The adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine according to claim 1, characterized in that: The adjustment component includes a driving component, a linkage component, and multiple sets of transmission components, with each set of transmission components connected to one of the air venting tube units; The rotating shaft of the inner grille extends out of the outer grille and is connected to the transmission assembly. Multiple sets of the transmission assemblies are connected to a linkage member, which is driven by the driving member to synchronously drive all the inner grilles to rotate.

7. The adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine according to claim 6, characterized in that: The linkage is a ring structure and is arranged around the outside of the combustion chamber casing; multiple sets of the transmission components are evenly distributed circumferentially and are connected to the linkage for transmission.

8. The adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine according to claim 7, characterized in that: The transmission assembly includes a rocker arm and a connecting rod; both ends of the connecting rod are respectively provided with universal joints, one end of which is rotatably connected to the rocker arm through the universal joint, and the other end of which is rotatably connected to the linkage through the universal joint. The end of the rocker arm away from the connecting rod is connected to the pivot of the inner grid.

9. The adjustable bleed air mechanism for a high-pressure turbine in the combustion chamber of an aero-engine according to claim 8, characterized in that: The drive unit includes at least two drive motors that are evenly distributed circumferentially outside the rear casing of the combustion chamber, and the output ends of multiple sets of drive motors are connected to the linkage. The drive motor drives the linkage to move axially, and the movement is converted into rotation of the inner grille through the transmission assembly.

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