Double-layer casing air-blast structure and design method thereof

Abstract

The application discloses a double-layer machine case air guiding structure and a design method thereof, and comprises the following steps: S1: determining the air guiding position on the compressor according to the air guiding demand and the compressor structure layout, so as to determine the air guiding position and design the related compressor stator and outer machine case; S2: preliminarily determining the air guiding characteristic of the air guiding hole one according to the air guiding demand and the flow area of the adjacent blade channel of the compressor stator, and then iteratively optimizing the air guiding characteristic of the air guiding hole one according to the air guiding demand and the flow condition of the main flow; S3: analyzing the vibration condition of the compressor stator and the adjacent compressor rotor, so as to iteratively optimize the air guiding hole one and ensure that the air guiding structure meets the vibration evaluation requirement; S4: iteratively optimizing the air guiding characteristic of the air guiding hole two according to the air guiding demand and the air guiding characteristic of the air guiding hole one; and S5: iteratively optimizing the air guiding hole one and the air guiding hole two in sequence by analyzing the air guiding demand under each typical working state of the engine.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular, to a design method for a double-layer casing bleed air structure. Furthermore, this invention also relates to a double-layer casing bleed air structure employing the aforementioned design method. Background Technology

[0002] In the field of aero-engines, in order to meet the functional requirements of engine anti-icing, turbine cooling, bearing cavity sealing, and starting bleed air, an bleed air structure is usually designed in the compressor of the aero-engine. After the compressor extracts air, the bleed air structure guides the flow of airflow through various structural components (holes, pipes, air collection chambers, etc.) and completes various functions. Among them, the bleed air flow rate and efficiency are important factors affecting the realization of various functions.

[0003] With the development of aero-engine technology, compressors are evolving towards lighter weight and more compact structure. Meanwhile, the temperature of hot-end components such as turbine inlets is gradually increasing, leading to a growing demand for bleed air flow. The existing bleed air structures in compressors mainly fall into the following three categories:

[0004] like Figure 1 As shown, in the first type of bleed air structure, the high-pressure gas in the mainstream airflow of the compressor enters the gas collecting chamber formed by the outer casing, front casing, and rear casing through the annular channel between the front casing and the rear casing, and then the bleed airflow is transported to a set position through the bleed air pipeline. However, since the annular channel is designed between the compressor rotor and the compressor stator, with the compact design of the rotor and stator, the distance between the compressor rotor and the compressor stator is reduced, the bleed air space is limited, and the bleed air flow rate is difficult to meet the bleed air requirements of the hot-end components. In addition, the front casing and the rear casing need to be designed separately for connection and installation structures with the outer casing, which also increases the structural complexity of the compressor.

[0005] like Figure 2 As shown, in the second type of bleed air structure, the high-pressure gas in the mainstream airflow of the compressor enters the gas collecting chamber formed by the outer and inner casings through the bleed air holes on the inner casing, and then the bleed airflow is delivered to the set position through the bleed air pipeline. However, since the bleed air holes on the inner casing are usually designed at the outlet of the compressor stator, with the compact design of the rotor and stator, the distance between the compressor rotor and the compressor stator is reduced, the bleed air space is limited, and the bleed air flow rate is difficult to meet the bleed air requirements of the hot end components; moreover, the bleed air holes are close to the compressor rotor, and the uneven airflow caused by the bleed air will have an adverse effect on the performance of the lower compressor rotor; in addition, the current compressor stator usually has a T-shaped tenon, which makes the space between the rotor and stator even more compact.

[0006] like Figure 3As shown, in the third type of bleed air structure, the high-pressure gas in the mainstream airflow of the compressor enters the gas collecting chamber formed by the compressor casing and the compressor stator through the bleed air holes on the compressor stator. The bleed airflow is then transported to a set position through bleed air pipes installed on the compressor casing. However, because the gas collecting chamber is located inside the compressor casing, its space is relatively small due to the radial thickness of the compressor casing. When the bleed airflow flows within this small space, significant bleed air losses occur, resulting in a reduced bleed air flow rate and decreased bleed air efficiency, making it difficult to meet the bleed air requirements of hot-end components.

[0007] It should be noted that the above background information is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of the present invention. In the absence of clear evidence that the above content was disclosed on the filing date of the present invention, the above background information should not be used to evaluate the novelty and inventiveness of the present invention. Summary of the Invention

[0008] This invention provides a double-layer casing bleed air structure and its design method to solve the technical problem that the existing bleed air structures in compressors cannot meet the bleed air requirements of hot-end components.

[0009] According to one aspect of the present invention, a method for designing a double-layer casing bleed air structure is provided, comprising the following steps: S1: determining the bleed air position on the compressor based on the bleed air requirements and compressor structural layout, and designing the relevant compressor stator and outer casing based on the bleed air position, so as to open a first bleed air hole on the compressor stator and open a second bleed air hole on the inner casing corresponding to the first bleed air hole, so that the compressor stator and the inner casing enclose a first gas collecting cavity that communicates with the first bleed air hole and the second bleed air hole respectively, and the outer casing and the inner casing enclose a second gas collecting cavity that communicates with the second bleed air hole and the bleed air pipeline respectively; S2: determining the bleed air position on the compressor stator based on the bleed air requirements and compressor stator adjacent to the first bleed air hole and the second bleed air hole respectively; S3: Analyze the vibration of the compressor stator and adjacent compressor rotor to iteratively optimize bleed air hole one, ensuring that the bleed air structure meets the vibration assessment requirements; S4: Iteratively optimize the bleed air characteristics of bleed air hole two based on the bleed air requirements and the bleed air characteristics of bleed air hole one; S5: By analyzing the bleed air requirements under various typical engine operating conditions, iteratively optimize bleed air hole one and bleed air hole two in sequence until the bleed air structure meets the bleed air requirements under various typical engine operating conditions.

[0010] As a further improvement to the above technical solution:

[0011] Furthermore, the air intake characteristics of air intake hole one include the flow area, shape, circumferential number, and axial position relative to the axial reference. The iterative optimization of the air intake characteristics of air intake hole one according to the air intake requirements and the flow of the mainstream airflow specifically includes the following steps: obtaining the airflow rate of air intake hole one through fluid simulation calculation; adjusting the flow area, shape, and circumferential number of air intake holes one according to the air intake requirements and airflow rate; and adjusting the axial position of air intake hole one relative to the axial reference according to the flow of the mainstream airflow until the air intake characteristics of air intake hole one that meet the set requirements of both the flow of the mainstream airflow and the air intake requirements are obtained.

[0012] Furthermore, the air intake characteristics of the second air intake hole include the flow area, shape, number of circumferential vents, axial position relative to the axial reference, and circumferential deviation angle relative to the first air intake hole.

[0013] Further, step S4 specifically includes the following steps: S41: Ensure that the axial positions of air vent two and air vent one relative to the axial reference are the same, the axial number of air vent two and air vent one is the same, and the circumferential deviation angle of air vent two relative to air vent one is 0°; S42: Obtain the streamline distribution and flow rate of the air venting through fluid simulation calculation, adjust the flow area of ​​air vent two according to the air venting requirements, the flow area of ​​air vent one, and the flow rate of the air venting, and adjust the shape of air vent two according to the flow rate of the air venting; S43: Based on the streamline distribution of the air venting, fine-tune the axial position of air vent two relative to the axial reference in increments of 0.2 mm, and fine-tune the circumferential deviation angle of air vent two relative to air vent one in increments of 0.1°. After the fine-tuning is completed, perform fluid simulation calculation until the air venting characteristics of air vent two that meet the set requirements for both air venting loss and air venting flow rate are obtained.

[0014] Further, step S3 specifically includes the following steps: by conducting vibration characteristic calculation and analysis, simulation software is used to calculate the resonant speed and vibration frequency margin of the compressor stator and the adjacent compressor rotor under the influence of the bleed air hole, so as to determine whether the bleed air structure meets the vibration assessment requirements. If the bleed air structure meets the vibration assessment requirements, the subsequent steps are carried out. If the vibration assessment requirements are not met, steps S2-S3 are repeated.

[0015] According to another aspect of the present invention, a double-layer casing bleed air structure is also provided, which adopts the above-described double-layer casing bleed air structure design method. The double-layer casing bleed air structure includes a compressor stator, a first bleed air port opened on the compressor stator, an inner casing, a second bleed air port opened on the inner casing, an outer casing, and a bleed air pipeline communicating with the outer casing. The compressor stator and the inner casing enclose a first air collecting chamber that communicates with the first bleed air port and the second bleed air port respectively. The outer casing and the inner casing enclose a second air collecting chamber that communicates with the second bleed air port and the bleed air pipeline respectively.

[0016] As a further improvement to the above technical solution:

[0017] Furthermore, there are multiple air intake holes, which are evenly spaced along the circumference of the compressor stator. Air intake holes are arranged in a corresponding manner to air intake holes one by one, and the circumferential deviation angle of air intake holes two relative to the corresponding air intake holes one is 0° to 2°.

[0018] Furthermore, the axial distance between the first air intake hole and the axial reference is D1, and the axial distance between the second air intake hole and the axial reference is D2, with D1-D2 ranging from -6mm to 6mm.

[0019] Furthermore, the second air intake hole is a square hole with rounded corners.

[0020] Furthermore, both the compressor stator and the inner casing are circumferentially split-half structures.

[0021] The present invention has the following beneficial effects:

[0022] The double-layer casing bleed air structure design method of the present invention determines the bleed air position on the compressor based on the bleed air requirements and compressor structural layout. Based on the bleed air position, the related compressor stator and outer casing are designed. A first bleed air hole is opened on the compressor stator, and a second bleed air hole corresponding to the first bleed air hole is opened on the inner casing. The compressor stator and inner casing enclose a first gas collecting chamber that communicates with the first and second bleed air holes respectively. The outer casing and inner casing enclose a second gas collecting chamber that communicates with the second bleed air hole and the bleed air pipeline respectively. High-pressure gas in the main compressor airflow first flows into the first gas collecting chamber through the first bleed air hole on the compressor stator. The air then flows into the second air collection chamber through the second air bleed port on the inner casing, and finally is delivered to the designated position through the air bleed pipeline to meet the bleed air requirements of the aircraft and engine. With air bleed through the first air bleed port on the compressor stator and the second air bleed port on the inner casing, the bleed air space is no longer limited by the axial distance between the compressor stator and the compressor rotor, providing a larger bleed air flow rate for the aircraft and engine. Based on the bleed air requirements and the flow area of ​​the adjacent blade passages of the compressor stator, the bleed air characteristics of the first air bleed port are initially determined. Then, based on the bleed air requirements and the flow conditions of the mainstream airflow, the bleed air characteristics of the first air bleed port are iteratively optimized to obtain a mainstream airflow... The bleed air characteristics of bleed air port one are determined by analyzing the flow conditions and bleed air requirements, ensuring they meet the set requirements. The vibration of the compressor stator and adjacent compressor rotors is analyzed to iteratively optimize bleed air port one, ensuring the bleed air structure meets vibration assessment requirements and that the impact of uneven airflow caused by bleed air on the compressor rotor meets the set requirements. Based on the bleed air requirements and the bleed air characteristics of bleed air port one, the bleed air characteristics of bleed air port two are iteratively optimized to obtain bleed air characteristics of bleed air port two that meet the set requirements for both bleed air loss and bleed air flow rate. Finally, by analyzing the bleed air requirements under various typical engine operating conditions, bleed air port one and bleed air port two are sequentially optimized. The process involves iterative optimization until the bleed air structure meets the bleed air requirements under various typical engine operating conditions. Specifically, by meticulously designing bleed air inlet one and bleed air inlet two, the bleed air loss when flowing through the relatively small gas collecting chamber one is significantly reduced, thereby improving bleed air flow rate and bleed air efficiency. Compared to existing technologies, this double-layer casing bleed air structure is not affected by the compact design of the compressor stator and compressor rotor, and it reduces the bleed air loss when flowing through gas collecting chamber one. It can provide a larger bleed air flow rate to meet the bleed air requirements of hot-end components, while not increasing the structural complexity of the compressor. It is highly practical and suitable for widespread promotion and application.

[0023] The double-casing bleed air structure of this invention allows high-pressure gas in the main airflow of the compressor to first flow into the first gas collection chamber through bleed air port one on the compressor stator, and then into the second gas collection chamber through bleed air port two on the inner casing. Finally, the bleed airflow is delivered to a set position through the bleed air pipeline to meet the bleed air requirements of the aircraft and engine. With bleed air port one on the compressor stator, the bleed air space is no longer limited by the axial distance between the compressor stator and the compressor rotor, and is not affected by the compact design of the compressor stator and compressor rotor. This allows for a larger bleed air flow rate for the aircraft and engine. At the same time, the optimized design of bleed air port one and bleed air port two can significantly reduce the bleed air loss in the first gas collection chamber, resulting in high bleed air flow rate and bleed air efficiency without increasing the complexity of the compressor structure. This design is highly practical and suitable for widespread promotion and application.

[0024] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the existing first-type air-entraining structure;

[0027] Figure 2 This is a schematic diagram of an existing second-type air-entraining structure;

[0028] Figure 3 This is a schematic diagram of the existing third-round air extraction structure;

[0029] Figure 4 This is a flowchart illustrating the steps of a preferred embodiment of the double-layer casing bleed air structure design method of the present invention;

[0030] Figure 5 This is a schematic diagram of the flow field calculation results of the double-layer casing air bleed structure in the design method of the double-layer casing air bleed structure of the preferred embodiment of the present invention;

[0031] Figure 6 This is a partial cross-sectional schematic diagram of the double-layer casing air bleed structure according to a preferred embodiment of the present invention;

[0032] Figure 7 yes Figure 6 A schematic diagram of the double-layer casing bleed air structure shown in direction A. Figure 1 ;

[0033] Figure 8 yes Figure 6 A schematic diagram of the double-layer casing bleed air structure shown in direction A. Figure 2 ;

[0034] Figure 9 yes Figure 6 The diagram shows a cross-sectional view of the double-layer casing bleed air structure.

[0035] Legend:

[0036] 11. Compressor stator; 12. Compressor rotor; 13. Inner casing; 14. Air vent 1; 15. Air vent 2; 16. Outer casing; 17. Air vent line; 18. Air collection chamber 1; 19. Air collection chamber 2. Detailed Implementation

[0037] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification.

[0038] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein may also include the plural forms. When used in this specification, the terms “comprising,” “including,” and / or “containing” mean that the associated integers, steps, operations, elements, and / or components are present, but do not preclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups, or that other features, integers, steps, operations, elements, components, and / or groups may be added to the system / method.

[0039] Considering the following description, these and other features of this specification, as well as the operation and function of the related components of the structure, and the economy of assembly and manufacture of the parts, can be significantly improved. All of these form part of this specification with reference to the accompanying drawings. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0040] like Figure 4 and Figure 6As shown, the double-layer casing bleed air structure design method of this embodiment includes the following steps: S1: Determine the bleed air position on the compressor according to the bleed air requirements and compressor structure layout, and design the relevant compressor stator 11 and outer casing 16 based on the bleed air position, so as to open a bleed air hole 14 on the compressor stator 11 and open a bleed air hole 15 on the inner casing 13 corresponding to the bleed air hole 14, so that the compressor stator 11 and the inner casing 13 enclose a gas collecting cavity 18 that is connected to the bleed air hole 14 and the bleed air hole 15 respectively, and the outer casing 16 and the inner casing 13 enclose a gas collecting cavity 19 that is connected to the bleed air hole 15 and the bleed air pipeline 17 respectively; S2: Determine the bleed air position on the compressor according to the bleed air requirements and compressor structure layout, so as to design the relevant compressor stator 11 and outer casing 16 based on the bleed air position, and design the relevant compressor stator 11 and outer casing 16 based on the bleed air position, so as to open a bleed air hole 14 on the compressor stator 11 and a bleed air hole 15 corresponding to the bleed air hole 14 and the bleed air hole 15 respectively, so as to open a gas collecting cavity 19 that is connected to the bleed air hole 15 and the bleed air pipeline 17 respectively; S2: Determine the bleed air position on the compressor stator 11 according to the bleed air requirements and compressor structure layout, so as to open a bleed air hole 14 on the compressor stator 11 and an bleed air hole 15 corresponding to the bleed air hole 14 and the bleed air hole 15 respectively, and design the relevant compressor stator 11 and outer casing 16 based on the bleed air position, so as to open S1: Calculate the flow area of ​​the adjacent blade passage of compressor stator 11 to initially determine the bleed air characteristics of bleed air inlet 14. Then, iteratively optimize the bleed air characteristics of bleed air inlet 14 based on the bleed air demand and the flow of the mainstream airflow. S2: Analyze the vibration of compressor stator 11 and adjacent compressor rotor 12 to iteratively optimize bleed air inlet 14 and ensure that the bleed air structure meets the vibration assessment requirements. S3: Iteratively optimize the bleed air characteristics of bleed air inlet 15 based on the bleed air demand and the bleed air characteristics of bleed air inlet 14. S4: By analyzing the bleed air demand under various typical operating conditions of the engine, iteratively optimize bleed air inlet 14 and bleed air inlet 15 in sequence until the bleed air structure meets the bleed air requirements under various typical operating conditions of the engine.

[0041] like Figure 4 and Figure 6As shown, specifically, the double-layer casing bleed air structure design method of the present invention determines the bleed air position on the compressor according to the bleed air requirements and compressor structural layout. Based on the bleed air position, the relevant compressor stator 11 and outer casing 16 are designed to open a first bleed air hole 14 on the compressor stator 11 and a second bleed air hole 15 corresponding to the first bleed air hole 14 on the inner casing 13. The compressor stator 11 and inner casing 13 enclose a first air collecting cavity 18 that communicates with the first bleed air hole 14 and the second bleed air hole 15 respectively. The outer casing 16 and inner casing 13 enclose a second air collecting cavity 19 that communicates with the second bleed air hole 15 and the bleed air pipe 17 respectively. The high-pressure gas in the main airflow of the compressor first passes through the compressor. Air flows from bleed port 14 on compressor stator 11 into air collection chamber 18, then through bleed port 15 on inner casing 13 into air collection chamber 19, and finally through bleed pipe 17 to deliver the bleed air flow to a set position to meet the bleed air requirements of the aircraft and engine. With bleed air from bleed port 14 on compressor stator 11 and bleed port 15 on inner casing 13, the bleed air space is no longer limited by the axial distance between compressor stator 11 and compressor rotor 12, providing a larger bleed air flow rate for the aircraft and engine. Based on the bleed air requirements and the flow area of ​​the adjacent blade passages of compressor stator 11, the bleed air characteristics of bleed port 14 are initially determined. Then, based on the bleed air requirements and the flow conditions of the mainstream airflow, the bleed air characteristics of bleed port 14 are further refined. The bleed air characteristics of bleed air port 14 are iteratively optimized to obtain bleed air characteristics that satisfy both the mainstream airflow and bleed air demand. The vibration of compressor stator 11 and adjacent compressor rotor 12 is analyzed to iteratively optimize bleed air port 14, ensuring the bleed air structure meets vibration assessment requirements and that the impact of uneven airflow caused by bleed air on compressor rotor 12 meets set requirements. Based on bleed air demand and the bleed air characteristics of bleed air port 14, the bleed air characteristics of bleed air port 15 are iteratively optimized to obtain bleed air characteristics that satisfy both bleed air loss and bleed air flow rate. Finally, the bleed air demand under various typical engine operating conditions is analyzed to sequentially optimize the bleed air characteristics of bleed air port 15. Iterative optimization was carried out on bleed air port 14 and bleed air port 15 until the bleed air structure met the bleed air requirements under various typical engine operating conditions. That is, by ingeniously designing bleed air port 14 and bleed air port 15, the bleed air loss when flowing through the relatively small air collection chamber 18 was significantly reduced, thereby improving the bleed air flow rate and bleed air efficiency. Compared with the prior art, the double-layer casing bleed air structure of this solution is not affected by the compact design of the compressor stator 11 and compressor rotor 12, and reduces the bleed air loss when flowing through the air collection chamber 18. It can provide a larger bleed air flow rate to meet the bleed air requirements of hot-end components, while not increasing the structural complexity of the compressor. It is highly practical and suitable for widespread promotion and application.

[0042] It should be understood that bleed air requirements refer to the bleed air requirements of the aircraft and its engines.

[0043] Optionally, step S5 specifically includes the following steps: by analyzing the bleed air requirements under various typical operating conditions of the engine, it is determined whether the bleed air structure meets the bleed air requirements under various typical operating conditions of the engine. When the bleed air structure meets the bleed air requirements under various typical operating conditions of the engine, the design structure is output. When the bleed air structure does not meet the bleed air requirements under various typical operating conditions of the engine, steps S2-S5 are repeated to iteratively optimize bleed air port 14 and bleed air port 15 in sequence until the bleed air structure meets the bleed air requirements under various typical operating conditions of the engine.

[0044] In this embodiment, the air intake characteristics of the air intake hole 14 include the flow area, shape, circumferential number, and axial position relative to the axial reference. The iterative optimization of the air intake characteristics of the air intake hole 14 according to the air intake requirements and the flow of the mainstream airflow specifically includes the following steps: obtaining the airflow rate of the air intake hole 14 through fluid simulation calculation; adjusting the flow area, shape, and circumferential number of the air intake hole 14 according to the air intake requirements and airflow rate; and adjusting the axial position of the air intake hole 14 relative to the axial reference according to the flow of the mainstream airflow until the air intake characteristics of the air intake hole 14 are obtained such that the flow of the mainstream airflow and the air intake requirements both meet the set requirements.

[0045] Specifically, the preliminary design of the air intake hole 14 is completed through the above steps to ensure that the airflow rate drawn from the air intake hole 14 to the air collection chamber 18 meets the air intake requirements, that is, the impact on the flow of the mainstream airflow is within the set requirements.

[0046] In this embodiment, the air intake characteristics of the second air intake hole 15 include the flow area, shape, number of circumferential directions, axial position relative to the axial reference, and circumferential deviation angle relative to the first air intake hole 14.

[0047] Specifically, by determining the influence of the second air intake hole 15 on the air intake flow through the above-mentioned air intake characteristics, the air intake loss when the air intake flow passes through the first air collection chamber 18 is reduced, thereby improving the air intake flow rate and air intake efficiency.

[0048] like Figure 7 and Figure 8As shown, in this embodiment, step S4 specifically includes the following steps: S41: Ensure that the axial positions of air intake hole 2 15 and air intake hole 14 relative to the axial reference are the same, the axial number of air intake hole 2 15 and air intake hole 14 is the same, and the circumferential deviation angle of air intake hole 2 15 relative to air intake hole 14 is 0°; S42: Obtain the streamline distribution and flow rate of the air intake airflow through fluid simulation calculation, and adjust the air intake according to the air intake requirements, the flow area of ​​air intake hole 14 and the flow rate of the air intake airflow. The flow area of ​​orifice 15 is adjusted according to the flow rate of the induced airflow. S43: Based on the streamline distribution of the induced airflow, the axial position of orifice 15 relative to the axial reference is fine-tuned in increments of 0.2 mm, and the circumferential deviation angle of orifice 15 relative to induced airflow 14 is fine-tuned in increments of 0.1°. After fine-tuning, fluid simulation calculations are performed until the induced airflow characteristics of orifice 15 are obtained, ensuring that both induced airflow loss and induced airflow rate meet the set requirements. Specifically, the preliminary design of orifice 15 is completed through the above steps to reduce induced airflow loss in the gas collecting chamber 18 and improve induced airflow rate and induced airflow efficiency.

[0049] It should be understood that the set requirements are met when the bleed air loss is minimized and the bleed air flow rate is maximized.

[0050] In this embodiment, step S3 specifically includes the following steps: By conducting vibration characteristic calculation and analysis, simulation software is used to calculate the resonant speed and vibration frequency margin of the compressor stator 11 and the adjacent compressor rotor 12 under the influence of the bleed air port 14, in order to determine whether the bleed air structure meets the vibration assessment requirements. If the bleed air structure meets the vibration assessment requirements, subsequent steps are carried out; if it does not meet the vibration assessment requirements, steps S2-S3 are repeated. Specifically, the above steps ensure that the bleed air structure meets the vibration assessment requirements, so that the adverse effects of the uneven airflow caused by the bleed air on the compressor rotor 12 are still within the set requirements.

[0051] like Figure 5 As shown in the figure, in this embodiment, the flow field simulation calculation results show that the optimized air vent 14 and air vent 2 15 are more adaptable to the flow of air venting and have less air venting damage.

[0052] like Figure 6 As shown, the double-layer casing air bleed structure of this embodiment adopts the above-mentioned double-layer casing air bleed structure design method. The double-layer casing air bleed structure includes a compressor stator 11, an air bleed hole 14 opened on the compressor stator 11, an inner casing 13, an air bleed hole 15 opened on the inner casing 13, an outer casing 16, and an air bleed pipe 17 connected to the outer casing 16. The compressor stator 11 and the inner casing 13 enclose an air collecting chamber 18 that is connected to the air bleed hole 14 and the air bleed hole 15 respectively. The outer casing 16 and the inner casing 13 enclose an air collecting chamber 29 that is connected to the air bleed hole 15 and the air bleed pipe 17 respectively.

[0053] like Figure 6 As shown, specifically, in the double-layer casing bleed air structure of the present invention, the high-pressure gas in the mainstream airflow of the compressor first flows into the air collection chamber 18 through the bleed air hole 14 on the compressor stator 11, then flows into the air collection chamber 19 through the bleed air hole 15 on the inner casing 13, and finally the bleed airflow is delivered to a set position through the bleed air pipeline 17 to meet the bleed air requirements of the aircraft and engine. The bleed air hole 14 is opened on the compressor stator 11, and the bleed air space is no longer limited by the axial distance between the compressor stator 11 and the compressor rotor 12, and is not affected by the compact design of the compressor stator 11 and the compressor rotor 12. It can provide a larger bleed air flow rate for the aircraft and engine. At the same time, the optimized design of the bleed air hole 14 and the bleed air hole 15 can significantly reduce the bleed air loss in the air collection chamber 18. The bleed air flow rate and bleed air efficiency are high, and it does not increase the complexity of the compressor structure. It is highly practical and suitable for widespread promotion and application.

[0054] like Figure 9 As shown, in this embodiment, multiple air intake holes 14 are provided, and the multiple air intake holes 14 are evenly arranged at intervals along the circumference of the compressor stator 11. Air intake holes 15 are arranged corresponding to air intake holes 14, and the circumferential deviation angle of air intake holes 15 relative to the corresponding air intake holes 14 is 0° to 2°. Specifically, when the induced airflow flows in the air collecting chamber 18, there is a circumferential velocity component. Therefore, by setting the circumferential deviation angle of air intake holes 15 relative to the corresponding air intake holes 14 to 0° to 2°, the flow direction of the induced airflow is adapted to minimize the induced airflow loss when flowing through the air collecting chamber 18. When the circumferential deviation angle of air intake holes 15 relative to the corresponding air intake holes 14 is greater than 2°, the induced airflow impacts the inner wall of the air collecting chamber 18, which will increase the flow loss of the induced airflow when flowing through the air collecting chamber 18.

[0055] Preferably, the circumferential deviation angle of the second air vent 15 relative to the corresponding first air vent 14 is 0.5°.

[0056] It should be understood that the direction of the circumferential deviation angle is the same as the direction of the circumferential deflection of the airflow.

[0057] like Figure 7 and Figure 8As shown, in this embodiment, the axial distance between air vent 14 and the axial reference is D1, and the axial distance between air vent 15 and the axial reference is D2, where D1-D2 is -6mm to 6mm. Specifically, when D1-D2 is between -6mm and 6mm, the axial distance between air vent 14 and air vent 15 is close, resulting in less energy dissipation of the airflow in the air collecting chamber 18 and less air loss. When D1-D2 is less than -6mm or greater than 6mm, the axial distance between air vent 14 and air vent 15 is far, resulting in greater energy dissipation of the airflow in the air collecting chamber 18 and greater air loss.

[0058] Preferably, D1-D2 is -2mm, so that the second air intake hole 15 is closer to the compressor rotor 12 than the first air intake hole 14, in order to adapt to the axial velocity component of the air intake flow in the first air collection chamber 18, thereby reducing the air intake loss of the air intake flow through the first air collection chamber 18.

[0059] like Figure 8 As shown, in this embodiment, the second air intake hole 15 is a square hole with rounded corners. Specifically, by making the second air intake hole 15 a square hole with rounded corners, the square hole can increase the flow area compared to a circular hole, thereby increasing the air intake flow rate.

[0060] Alternatively, in one embodiment, the square orifice increases the flow area by approximately 15% compared to the circular orifice, and has virtually no impact on the structural strength of the inner casing 13.

[0061] Alternatively, in another embodiment, the second air vent 15 is a waist-shaped vent.

[0062] like Figure 7 As shown, optionally, the air vent 14 is a circular hole, which has good machinability.

[0063] Optionally, the bleed air port 14 is positioned near the outlet of the compressor stator 11 to increase the bleed air pressure.

[0064] Optionally, the flow area of ​​the second air vent 15 is larger than the flow area of ​​the first air vent 14.

[0065] In this embodiment, both the compressor stator 11 and the inner casing 13 are circumferentially split structures. Specifically, the compressor stator 11 has a structure with a T-shaped tenon and is installed and fixed through two annular grooves at the front and rear. The circumferentially split structure of the compressor stator 11 facilitates installation. Furthermore, the circumferentially split structure of the inner casing 13 facilitates installation while adapting to the structure of the compressor stator 11.

[0066] In summary, after reading the detailed disclosure of this specification, those skilled in the art will understand that the foregoing detailed disclosure is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that this specification requires various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this specification and are within the spirit and scope of the exemplary embodiments described herein.

[0067] Furthermore, certain terms in this specification have been used to describe embodiments of this specification. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this specification. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be suitably combined in one or more embodiments of this specification.

[0068] It should be understood that in the foregoing description of the embodiments in this specification, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the description and aiding in the understanding of a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may readily identify some of the devices as separate embodiments when reading this specification. That is, the embodiments in this specification can also be understood as an integration of multiple secondary embodiments. It is also valid when each secondary embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0069] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments described in this specification. Other modified embodiments are also within the scope of this specification. Therefore, the embodiments disclosed in this specification are merely examples and not limitations. Those skilled in the art can implement the applications described in this specification using alternative configurations based on the embodiments in this specification. Therefore, the embodiments in this specification are not limited to the embodiments precisely described in the applications.

Claims

1. A design method for a double-layer casing bleed air structure, characterized in that, Includes the following steps: S1: Determine the bleed position on the compressor based on the bleed requirements and compressor structure layout, and design the relevant compressor stator (11) and outer casing (16) based on the bleed position, so as to open bleed hole one (14) on the compressor stator (11) and open bleed hole two (15) on the inner casing (13) corresponding to bleed hole one (14), so that the compressor stator (11) and the inner casing (13) enclose to form a gas collection chamber one (18) that is connected to bleed hole one (14) and bleed hole two (15) respectively, and make the outer casing (16) and the inner casing (13) enclose to form a gas collection chamber two (19) that is connected to bleed hole two (15) and bleed pipeline (17) respectively. S2: Based on the bleed air demand and the flow area of ​​the adjacent blade channel of the compressor stator (11), the bleed air characteristics of bleed air hole one (14) are initially determined, and then the bleed air characteristics of bleed air hole one (14) are iteratively optimized based on the bleed air demand and the flow of the mainstream airflow. S3: Analyze the vibration of the compressor stator (11) and the adjacent compressor rotor (12) to carry out iterative optimization of the air intake hole (14) to ensure that the air intake structure meets the vibration evaluation requirements; S4: Based on the air intake requirements and the air intake characteristics of air intake hole one (14), the air intake characteristics of air intake hole two (15) are iteratively optimized. S5: By analyzing the bleed air requirements under various typical working conditions of the engine, the bleed air port one (14) and bleed air port two (15) are iteratively optimized in sequence until the bleed air structure meets the bleed air requirements under various typical working conditions of the engine. The air intake characteristics of air intake hole one (14) include flow area, shape, circumferential number, and axial position relative to the axial reference. The air intake characteristics of air intake hole one (14) are iteratively optimized according to the air intake requirements and the flow of the mainstream airflow, specifically including the following steps: The flow rate of the air vent (14) is obtained by fluid simulation calculation. The flow area, shape and number of circumferential parts of the air vent (14) are adjusted according to the air venting requirements and air flow rate. The axial position of the air vent (14) relative to the axial reference is then adjusted according to the flow of the mainstream airflow until the air venting characteristics of the air vent (14) are obtained so that the flow of the mainstream airflow and the air venting requirements meet the set requirements. Step S4 specifically includes the following steps: S41: Ensure that the axial positions of the second air intake hole (15) and the first air intake hole (14) are the same relative to the axial reference, the number of the second air intake hole (15) and the first air intake hole (14) are the same, and the circumferential deviation angle of the second air intake hole (15) relative to the first air intake hole (14) is 0°. S42: The streamline distribution and flow rate of the bleed air flow are obtained through fluid simulation calculation. The flow area of ​​the bleed air hole 1 (14) and the flow rate of the bleed air flow are adjusted according to the bleed air demand, the flow area of ​​the bleed air hole 1 (14) and the flow rate of the bleed air flow. The shape of the bleed air hole 2 (15) is adjusted according to the flow rate of the bleed air flow. S43: Based on the streamline distribution of the bleed air flow, fine-tune the axial position of the second bleed air hole (15) relative to the axial reference in increments of 0.2 mm, and fine-tune the circumferential deviation angle of the second bleed air hole (15) relative to the first bleed air hole (14) in increments of 0.1°. After the fine-tuning is completed, perform fluid simulation calculations until the bleed air characteristics of the second bleed air hole (15) that meet the set requirements for both bleed air loss and bleed air flow rate are obtained.

2. The design method for the double-layer casing bleed air structure according to claim 1, characterized in that, The air intake characteristics of the second air intake hole (15) include the flow area, shape, number of circumferential directions, axial position relative to the axial reference, and circumferential deviation angle relative to the first air intake hole (14).

3. The design method for the double-layer casing bleed air structure according to any one of claims 1-2, characterized in that, Step S3 specifically includes the following steps: By conducting vibration characteristic calculation and analysis, simulation software is used to calculate the resonant speed and vibration frequency margin of the compressor stator (11) and the adjacent compressor rotor (12) under the influence of the first air intake hole (14) to determine whether the air intake structure meets the vibration evaluation requirements. If the air intake structure meets the vibration evaluation requirements, the subsequent steps are carried out. If the vibration evaluation requirements are not met, steps S2-S3 are repeated.

4. A double-layer casing bleed air structure, characterized in that, The double-layer casing air bleed structure design method according to any one of claims 1-3 includes a compressor stator (11), an air bleed hole one (14) opened on the compressor stator (11), an inner casing (13), an air bleed hole two (15) opened on the inner casing (13), an outer casing (16), and an air bleed pipe (17) connected to the outer casing (16). The compressor stator (11) and the inner casing (13) enclose each other to form an air collection chamber one (18) that is connected to the air bleed hole one (14) and the air bleed hole two (15) respectively. The outer casing (16) and the inner casing (13) enclose each other to form an air collection chamber two (19) that is connected to the air bleed hole two (15) and the air bleed pipe (17) respectively.

5. The double-layer casing bleed air structure according to claim 4, characterized in that, Multiple air intake holes (14) are provided, and the multiple air intake holes (14) are evenly arranged at intervals along the circumference of the compressor stator (11). Air intake holes (25) are arranged in a corresponding manner to air intake holes (14), and the circumferential deviation angle of air intake holes (25) relative to the corresponding air intake holes (14) is 0° to 2°.

6. The double-layer casing bleed air structure according to claim 4, characterized in that, The axial distance between the first air vent (14) and the axial distance between the second air vent (15) and the axial distance between the second air vent (15) and the axial distance between the second air vent and the axial distance are D2, with D1-D2 being -6mm to 6mm.

7. The double-layer casing bleed air structure according to claim 4, characterized in that, The second air intake hole (15) is a square hole with rounded corners.

8. The double-layer casing bleed air structure according to claim 4, characterized in that, Both the compressor stator (11) and the inner casing (13) are circumferentially split structures.

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