Rear casing guide vane and design method thereof

Abstract

The invention provides a rear casing guide vane and a design method thereof, and relates to the technical field of power machinery. The rear casing guide vane design method comprises the steps that S01, according to guide vane design information, a vane profile is designed, and a designed vane profile is obtained; the blade profile design comprises an inlet airflow angle, an outlet airflow angle, the maximum thickness and the axial chord length, and the position of the maximum thickness is within the range of 0.2-0.3 of the axial chord length; s02, generating a geometric model of the designed blade profile, and performing numerical calculation on the geometric model; s03, analyzing a numerical calculation result, and if an analysis result does not meet the design requirement, carrying out iterative design on the blade profile until the design requirement is met; and S04, variable working condition analysis is conducted on the blade profiles meeting the design requirements. The rear casing guide vane design method can adapt to an inlet large pre-rotation angle rear casing, the total pressure loss of the rear casing is reduced, and the economical efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power machinery, and in particular to a rear casing guide vane and a design method thereof. Background Art

[0002] The continuously improving technical indicators of large civil aviation engines or gas turbines have placed very high demands on them. Low fuel consumption, high reliability and long life are the basic characteristics of modern aviation engines and gas turbines. Therefore, new technical challenges have been raised for the design of each component. In order to increase the output power of the turbine components, the airflow angle of the outlet of the last-stage moving blades deviates from the axial direction more and more, and even deviates from the axial direction by more than 20°. At the same time, the flow loss of the exhaust rear casing is required to be as small as possible, otherwise it will lead to a higher fuel consumption rate or fuel consumption. Due to the requirements of reliability and high efficiency, when the engine is running under different working conditions, the rear casing is required to have as low flow loss as possible. Therefore, the reasonable design of the rear casing guide vanes is of great significance to improving the performance of the whole machine.

[0003] The flow channel blades in the rear casing of the new turbine must not only consider lower flow losses, but also serve as the main support point of the aircraft engine or gas turbine. The internal pipeline functions include oil supply and return pipelines, ventilation pipes, etc., to achieve lubrication and sealing of the bearings. Therefore, a certain thickness must be guaranteed, which brings new challenges to ensuring lower total pressure losses. Summary of the invention

[0004] The purpose of the present invention is to provide a rear casing guide vane and a design method thereof, so as to improve the technical problem of large total pressure loss of the existing rear casing with a large inlet pre-swirl angle.

[0005] The embodiments of the present invention can be implemented in the following ways:

[0006] A method for designing a rear casing guide vane, comprising:

[0007] S01: performing blade profile design according to the guide vane design information to obtain a designed blade profile; the blade profile design includes an inlet airflow angle, an outlet airflow angle, a maximum thickness and an axial chord length, wherein the position of the maximum thickness is within a range of 0.2 to 0.3 of the axial chord length;

[0008] S02: generating a geometric model of the designed blade profile, and performing numerical calculation on the geometric model;

[0009] S03: Analyze the numerical calculation results. If the analysis results do not meet the design requirements, iteratively design the blade profile until the design requirements are met.

[0010] S04: Perform variable operating condition analysis on the blade profile that meets the design requirements.

[0011] Optionally, the blade profile of the guide vane is first designed, and after the blade profile in the blade that meets the design requirements is analyzed under variable operating conditions, the rear casing guide vane design method further includes:

[0012] S05: scaling the blade profile in the blade and adjusting the blade profile installation angle to obtain the initial design blade profile of the blade root and the blade tip;

[0013] S06: performing iterative design on the initial designed blade profile to obtain a final blade root blade profile and a blade tip blade profile;

[0014] S07: obtaining a rear casing guide vane according to the blade profile at the center, the blade profile at the root, and the blade profile at the tip.

[0015] Optionally, the step of obtaining the rear casing guide vane according to the blade-mid blade profile, the blade-root blade profile and the blade-tip blade profile comprises:

[0016] Generate a full blade height geometric model according to the blade mid-blade profile, blade root profile and blade tip profile;

[0017] Performing mesh verification on the full leaf height geometric model;

[0018] Combined with the chamfer design, the flow characteristics of the rear casing are analyzed and the total pressure loss characteristics of the rear casing are obtained.

[0019] Optionally, the steps of generating a geometric model of the designed blade profile and performing numerical calculation on the geometric model include:

[0020] generating a sheet-shaped geometric model having a cross section of the designed blade profile;

[0021] The sheet-like geometric model is meshed using fine mesh and HOH mesh topology, and flow field verification calculations are performed.

[0022] Optionally, the analysis of the numerical calculation results includes: inlet and outlet parameter analysis, blade surface static pressure distribution or isentropic Mach number distribution curve analysis, and total pressure loss analysis.

[0023] Optionally, if the analysis result does not meet the design requirements, the steps of iteratively designing the blade profile until the design requirements are met include:

[0024] If the analysis result does not meet the design requirements, return to step S01 to re-perform iterative blade design and numerical analysis;

[0025] In the process of iterative design, a macro is recorded for the process of step S02, and the execution of step S02 in the iterative design is realized through the macro.

[0026] Optionally, the rear casing guide vanes include engine rear casing guide vanes and gas turbine rear casing guide vanes, and the step of performing variable operating condition analysis on the blade profile that meets the design requirements includes:

[0027] For the engine rear casing guide vanes that meet the design requirements, calculation and analysis of the blade profile's angle of attack characteristics, Mach number characteristics, and Reynolds characteristics are performed;

[0028] The angle of attack characteristics and Mach number characteristics of the gas turbine rear casing guide vane that meets the design requirements are calculated and analyzed.

[0029] A rear casing guide vane is obtained according to the above-mentioned rear casing guide vane design method.

[0030] A rear casing guide vane, the rear casing guide vane being used for a rear casing whose inlet airflow angle deviates from the axial direction by 20° to 30°;

[0031] The rear casing guide vane is asymmetrical, and the maximum thickness position of the rear casing guide vane is within the range of 0.2 to 0.3 of the axial chord length.

[0032] The beneficial effects of the rear casing guide vane and the design method thereof provided by the embodiments of the present invention include:

[0033] The embodiment of the present invention provides a method for designing a guide vane of a rear casing, which includes S01: designing a blade profile according to the information of the guide vane design to obtain a designed blade profile; the blade profile design includes an inlet airflow angle, an outlet airflow angle, a maximum thickness and an axial chord length, wherein the position of the maximum thickness is within the range of 0.2 to 0.3 of the axial chord length; S02: generating a geometric model of the designed blade profile, and performing numerical calculation on the geometric model; S03: analyzing the numerical calculation results, and if the analysis results do not meet the design requirements, iteratively designing the blade profile until the design requirements are met; S04: performing variable operating condition analysis on the blade profile that meets the design requirements. The method for designing a guide vane of a rear casing can adapt to a rear casing with a large inlet pre-swirl angle, reduce the total pressure loss of the rear casing, and improve economy.

[0034] An embodiment of the present invention also provides a rear casing guide vane, which is designed using the above-mentioned rear casing guide vane design method, and therefore also has the beneficial effects of being able to adapt to an inlet large pre-rotation angle rear casing, reducing the total pressure loss of the rear casing, and improving economy.

[0035] The embodiment of the present invention also provides a rear casing guide vane, which is used for a rear casing with an airflow angle of 20° to 30° away from the axial direction. The rear casing guide vane is asymmetric, and the maximum thickness position of the rear casing guide vane is within the range of 0.2 to 0.3 of the axial chord length. The rear casing guide vane can adapt to a rear casing with a large inlet pre-swirl angle, reduce the total pressure loss of the rear casing, and improve economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0037] Figure 1 A schematic diagram of the flow of a rear casing of a low-pressure turbine of an aircraft engine provided according to one aspect of the present invention is shown;

[0038] Figure 2 A circumferential arrangement diagram of guide vanes of a rear casing of an aircraft engine provided according to one aspect of the present invention is shown;

[0039] Figure 3 It shows a flow diagram of a turbine exhaust casing 12 of a gas turbine provided according to one aspect of the present invention;

[0040] Figure 4 A circumferential arrangement diagram of the rear casing guide vanes of a gas turbine according to one aspect of the present invention is shown;

[0041] Figure 5 A schematic diagram of a cross-sectional blade structure of a rear casing guide vane provided according to one aspect of the present invention is shown;

[0042] Figure 6 A schematic diagram of the cross-sectional blade structure of an existing symmetrical rear casing guide blade is shown;

[0043] Figure 7 A flow chart of a method for designing a rear casing guide vane according to one aspect of the present invention is shown. DETAILED DESCRIPTION

[0044] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are only exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0045] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", "vertical" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] At the same time, it should be noted that the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified or limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, an integral connection, or a detachable 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, or the internal communication of two components, etc. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Figure 1 The flow diagram of the low-pressure turbine rear casing 11 of the aircraft engine provided in this embodiment is as follows: Figure 2 The circumferential arrangement diagram of the guide vanes of the rear casing of the aircraft engine provided in this embodiment, Figure 3 A flow diagram of a turbine exhaust casing 12 (also referred to as a rear casing) of a gas turbine provided in this embodiment, Figure 4 The circumferential arrangement diagram of the guide vanes of the rear casing of the gas turbine provided in this embodiment, Figure 5 This is a schematic diagram of the cross-sectional blade structure of the rear casing guide blade 1 provided in this embodiment. Figure 1-Figure 5 , the rear casing guide vanes 1 (also referred to as OGV) include aircraft engine rear casing guide vanes and gas turbine rear casing guide vanes. The rear casing guide vanes 1 are generally hollow blades, and the hollow part can be used to arrange lubricating oil or ventilation pipes, which can reduce product weight and casting costs. The number of rear casing guide vanes of aircraft engines is generally more than that of gas turbines. The number of rear casing guide vanes of aircraft engines ranges from 12 to 18, and the number of rear casing guide vanes of gas turbines ranges from 4 to 8. The rear casing structure is described below:

[0049] The rear casing includes a rear casing guide vane and an outer flow channel and an inner flow channel located at both ends of the rear casing guide vane. The outer flow channel structure is also called an outer casing 2 or an upper edge plate of the guide vane, and the inner flow channel structure is also called an inner casing 3 or a lower edge plate of the guide vane. Figure 1 and Figure 3 The figure also shows the inlet section 4 and the outlet section 5 of the rear casing flow. A chamfered transition is set at the connection between the rear casing guide vane and the casing (the casing is a general term for the inner casing 3 and the outer casing 2). By setting the chamfered transition, the end zone flow is improved on the one hand, and the end strength margin can be increased on the other hand. At the same time, the size of the chamfer radius can be specifically set according to the strength or flow field requirements.

[0050] Specifically, the chamfer between the rear casing guide vane and the outer casing is called an upper chamfer, and the chamfer between the rear casing guide vane and the inner casing is called a lower chamfer. At the same time, the pressure surface side and the suction surface side of the rear casing guide vane can adopt a variable chamfer design. Specifically, the chamfer between the pressure surface side and the suction surface side of the rear casing guide vane and the outer casing are respectively the first upper chamfer 6 and the second upper chamfer 7, and the radius size of the first upper chamfer 6 can be set to be different from the radius size of the second upper chamfer 7. The chamfer between the pressure surface side and the suction surface side of the rear casing guide vane and the inner casing are respectively the first lower chamfer 8 and the second lower chamfer 9, and the radius size of the first lower chamfer 8 can be set to be different from the radius size of the second lower chamfer 9.

[0051] Below Figure 5 Taking the blade shown in the figure as an example, the basic structure of the blade is explained as follows: the blade has a relative suction surface 21 and a pressure surface 22. One end of the suction surface 21 and the pressure surface 22 are connected by a leading edge. The leading edge is in the shape of a circular arc and can be regarded as part of the small circle 25 at the leading edge. The other end of the suction surface 21 and the pressure surface 22 are connected by a trailing edge. The trailing edge is in the shape of a circular arc and can be regarded as part of the small circle 26 at the trailing edge. In the blade structure, the blade thickness refers to the diameter of a circle 24 tangent to the suction surface and the pressure surface, and the center of the circle 24 is located on the mid-arc line. Generally speaking, the thickness of the blade refers to the maximum thickness of the blade, such as Figure 5 The center of the center circle 24 shows the location of the maximum thickness of the airfoil.

[0052] like Figure 5 As shown, in order to adapt to the large inlet pre-spin angle (within the range of 20° to 30°), the rear casing guide vane provided in this embodiment adopts an asymmetric shape. Figure 6 The existing symmetrical rear casing guide vane is shown. Figure 5 and Figure 6 By comparison, it can be seen that in the asymmetric rear casing guide vane provided in this embodiment, the blade mid-arc line is used as the dividing line, and the parts on both sides of the axis are asymmetric. At the same time, in the asymmetric rear casing guide vane, the maximum thickness position is within the range of 0.2 to 0.3 of the axial chord length. This setting can not only adapt to the larger pre-swirl of the OGV inlet, but also reduce the total pressure loss of the rear casing, bringing certain economic benefits to the product. At the same time, compared with the symmetrical blade type (such as Figure 6 As shown in the figure), the blade area can be further reduced, thereby reducing the casting material and reducing the product weight.

[0053] It should be noted that the “maximum thickness position” referred to in this embodiment refers to the ratio of the axial distance from the center of the maximum thickness circle to the leading edge to the axial distance from the leading and trailing edges, that is, 0 at the leading edge and 1 at the trailing edge.

[0054] Figure 7 The flowchart of the design method of the rear casing guide vane provided by this embodiment is shown. Figure 7 The present embodiment also provides a method for designing a rear casing guide blade, which can be used to design the above-mentioned rear casing guide blade. Accordingly, the embodiment of the present invention can also be regarded as providing a rear casing guide blade designed according to the rear casing guide blade design method. Specifically, the method for designing a rear casing guide blade includes:

[0055] S01: Perform blade profile design based on the guide vane design information to obtain a designed blade profile.

[0056] Before starting the design of the rear casing guide vanes, relevant information about the design of the rear casing guide vanes can be collected, such as the overall structural design of the whole machine, casting size restrictions, pipeline layout requirements, maximum pipe diameter and other information, inlet and outlet boundary conditions, general inlet section given inlet airflow angle (or velocity component), inlet total temperature, total pressure, outlet section static pressure or flow restriction and other aerodynamic information.

[0057] The collected information is sorted out to carry out blade design and obtain the designed blade shape.

[0058] Optionally, in the rear casing guide vane design method provided in this embodiment, the blade profile of the middle blade of the rear casing guide vane (ie, at 50% of the blade height of the rear casing guide vane) is firstly designed.

[0059] The blade profile design includes the inlet airflow angle, outlet airflow angle, maximum thickness and axial chord length. Specifically, the blade profile parameters of the designed blade profile are set as follows:

[0060] a) The overall structural plan of the whole machine, determine the axial chord length or chord length of the blade profile of the rear casing guide vane;

[0061] b) Determine the maximum thickness of the blade according to the maximum outer diameter requirement of the pipeline;

[0062] c) The inlet airflow angle of the rear casing guide vane is set to the outlet airflow angle of the upstream turbine, generally deviating by 10° to 30° in the axial direction;

[0063] d) The outlet of the guide vane of the rear casing should be axially discharged as much as possible to generate greater thrust, and is generally controlled to deviate from the axial direction by ±5°;

[0064] e) According to the inlet and outlet airflow angles of the rear casing guide vane, the inlet and outlet geometric angles of the rear casing guide vane are selected; the inlet adopts a negative angle of attack design, and the angle of attack range of 2° to 5° is more suitable, and the outlet geometric angle deviates from the axial direction by 3° to 8°.

[0065] f) According to the range of the outlet airflow angle of the last stage turbine under the main operating conditions of the product, the appropriate leading edge radius of the blade profile can be selected. Generally speaking, the guide vanes of the turbine are larger than those of conventional turbines to accommodate better incoming flow;

[0066] g) Since the blade shape of the rear casing guide vane is larger than that of conventional turbine blades, the trailing edge radius is relatively no longer a design constraint;

[0067] h) The maximum thickness position of the blade of the rear casing guide vane is set within the range of 0.2 to 0.3 of the axial chord length. Specifically, the more the inlet angle of the rear casing guide vane deviates from the axial direction, the closer the maximum thickness position should be to the leading edge.

[0068] The designed blade shape is formed according to the range of the blade shape parameter settings mentioned above.

[0069] It should be noted that since the inlet and outlet area ratio of the aircraft engine rear casing is different from that of the gas turbine rear casing, the aerodynamic parameters of the aircraft engine rear casing outlet will be different from those of the gas turbine rear casing outlet. However, this will not affect the design of the blade profile in the mid-section of the blade. For the OGV plane blade grid, the flow channel inside the OGV blade grid is a process of increasing static pressure and reducing the Mach number, which is different from the conventional turbine blade design.

[0070] S02: Generate a geometric model of the designed blade profile and perform numerical calculations on the geometric model.

[0071] S21: Generate a sheet-shaped geometric model with a cross section of the designed blade shape. The thickness of the sheet-shaped geometric model can be set according to the design, and even only a surface model with the designed blade shape can be generated. The generated sheet-shaped geometric model is linear in the height direction. In other words, the sheet-shaped geometric model can be regarded as a plane stretching obtained with the designed blade shape.

[0072] S22: Input the obtained sheet geometry model into the software for blade meshing. Optionally, the sheet geometry model is meshed using a fine grid or HOH grid topology. Specifically, compared with conventional turbine blades, the consistency of the blades of the rear casing guide vanes is lower, and the numerical calculation of the blade multi-layer grid can improve the design efficiency. Moreover, when the inlet of the rear casing guide vane deviates from the axial direction by more than 20°, local separation is prone to occur on the blade surface, especially for the design of the rear casing guide vane of an aircraft engine. Local flow analysis is very likely to occur at high altitudes and the Reynolds number. This embodiment uses a fine grid or HOH grid topology to mesh the sheet geometry model for CFD flow field verification.

[0073] It should be noted that the fine grid here does not specifically refer to a grid of a certain size, but is achieved by directly selecting the fine grid option in the grid software.

[0074] S23: Use CFD software to perform numerical analysis and post-processing on the meshed geometric model.

[0075] S03: Analyze the numerical calculation results. If the analysis results do not meet the design requirements, iteratively design the blade profile until the design requirements are met.

[0076] The design point result analysis is given for the numerical calculation and post-processing results, which includes the inlet and outlet parameter analysis, the static pressure distribution on the blade surface or the isentropic Mach number distribution curve analysis, and the total pressure loss analysis. If the analysis result does not meet the design requirements, return to step S01 and perform steps S01, S02 and S03 again until the design requirements are met.

[0077] Since repeated iterative optimization design is required during the blade design process with a large number of iterations, a numerical extreme template can be used when performing numerical calculations on the geometric model. The processes in step S02, such as geometric input, meshing, numerical solution, and post-processing, can be recorded as macros, and the execution of step S02 in the iterative design can be implemented through the macro.

[0078] Specifically, the macro recording process can record and execute multiple macros according to the blade design software output file template, meshing software, and CFD software modules used by each OEM manufacturer, or a commercial optimization platform such as Isight software can be used to assist in automatic optimization.

[0079] S04: Analysis of blade profile variations that meet design requirements.

[0080] The designed blade shape that meets the design requirements is taken as the blade-in-blade shape, and the variable operating condition analysis is performed on the blade-in-blade shape.

[0081] The specific contents of the variable operating condition analysis include: according to the collected product operating condition range, the blade angle characteristics and Mach number characteristics are calculated and analyzed. At the same time, for the design of the aero-engine rear casing guide vane, due to the high altitude and low Reynolds number environment, the Reynolds number characteristic analysis is required. For the design of the gas turbine rear casing guide vane, since the inlet and outlet flow fields of the rear casing guide vane are in the self-modeling area (the gas turbine is operating in the ground condition), the Reynolds characteristic analysis is generally not required. After the analysis is completed, the blade-in-blade design is completed.

[0082] S05: scaling the blade profile in the blade and adjusting the blade profile installation angle to obtain the initial design blade profile of the blade root and the blade tip.

[0083] Taking the blade profile obtained above as a reference, the blade profile is adapted to the incoming flow conditions of different radial blade heights by adjusting the installation angle and scaling, and the adjusted blade profile is used as the initial design blade profile of the blade root profile and the initial design blade profile of the blade tip profile.

[0084] S06: Iterate the initial blade design to obtain the final blade root blade shape and blade tip blade shape.

[0085] The initial design blade profile of the blade root blade profile is iteratively designed. The specific iterative process can be performed according to the process of step S01 to step S03 until the blade profile obtained by iteration meets the design requirements of the blade root, and the blade profile is used as the final blade root blade profile.

[0086] The initial design blade profile of the blade tip is iteratively designed. The specific iterative process can be performed according to the process of step S01 to step S03 until the blade profile obtained by iteration meets the design requirements of the blade tip, and the blade profile is used as the final blade root blade profile.

[0087] S07: Obtain the rear casing guide vane according to the blade profile at the center, the blade profile at the root and the blade profile at the tip.

[0088] The blade root blade shape represents the cross-sectional blade shape at 0% of the blade height in the rear casing guide blade, the blade middle blade shape represents the cross-sectional blade shape at 50% of the blade height in the rear casing guide blade, and the blade tip blade shape represents the cross-sectional blade shape at 100% of the blade height in the rear casing guide blade. The full blade height geometric model of the rear casing guide blade is obtained according to the three blade shapes, and then the full blade height geometric model is meshed and verified. Optionally, when meshing the full blade height geometric model, it is set to 64 to 128 layers, and the mesh size can be selected as a fine mesh, or the mesh size can be set to an encrypted mesh that is more dense than the fine mesh, so as to perform encrypted mesh verification.

[0089] Finally, combined with the chamfered design of the upper edge plate and the chamfered design of the lower edge plate mentioned above, the flow characteristics of the rear casing are analyzed to obtain the total pressure loss characteristics of the rear casing, and the design of the casing guide vanes is completed.

[0090] The rear casing guide vane and the design method thereof provided by the embodiment of the present invention are suitable for non-axial exhaust at the final stage outlet of a modern new aircraft engine or a gas turbine, in particular, the inlet airflow angle of the rear casing deviates from the axial direction by 20° to 30°. The rear casing guide vane and the design method thereof can significantly reduce the total pressure loss of the rear casing, bring certain economic benefits to the product, and at the same time help reduce the weight of the product to meet the lightweight requirements.

[0091] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technology in the field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for designing a guide vane for a rear casing, characterized in that: The rear casing guide vane design method comprises: S01: performing blade profile design according to the guide vane design information to obtain a designed blade profile; the blade profile design includes an inlet airflow angle, an outlet airflow angle, a maximum thickness and an axial chord length, wherein the position of the maximum thickness is within a range of 0.2 to 0.3 of the axial chord length; S02: generating a geometric model of the designed blade profile, and performing numerical calculation on the geometric model; S03: Analyze the numerical calculation results. If the analysis results do not meet the design requirements, iteratively design the blade profile until the design requirements are met. S04: Perform variable operating condition analysis on the blade profile that meets the design requirements.

2. The method for designing a guide vane for a rear casing according to claim 1, characterized in that: First, the blade profile of the guide vane is designed. After the blade profile that meets the design requirements is analyzed under variable working conditions, the rear casing guide vane design method further includes: S05: scaling the blade profile in the blade and adjusting the blade profile installation angle to obtain the initial design blade profile of the blade root and the blade tip; S06: performing iterative design on the initial designed blade profile to obtain a final blade root blade profile and a blade tip blade profile; S07: obtaining a rear casing guide vane according to the blade profile at the center, the blade profile at the root, and the blade profile at the tip.

3. The method for designing the guide vanes of the rear casing according to claim 2, characterized in that: The step of obtaining the rear casing guide vane according to the blade-mid blade profile, the blade-root blade profile and the blade-tip blade profile comprises: Generate a full blade height geometric model according to the blade mid-blade profile, blade root profile and blade tip profile; Performing mesh verification on the full leaf height geometric model; Combined with the chamfer design, the flow characteristics of the rear casing are analyzed and the total pressure loss characteristics of the rear casing are obtained.

4. The method for designing a guide vane for a rear casing according to claim 1, characterized in that: The steps of generating a geometric model of the designed blade profile and performing numerical calculation on the geometric model include: generating a sheet-shaped geometric model having a cross section of the designed blade profile; The sheet-like geometric model is meshed using fine mesh and HOH mesh topology, and flow field verification calculations are performed.

5. The method for designing a guide vane for a rear casing according to claim 1, characterized in that: The analysis of numerical calculation results includes: inlet and outlet parameter analysis, blade surface static pressure distribution or isentropic Mach number distribution curve analysis and total pressure loss analysis.

6. The method for designing a guide vane for a rear casing according to claim 1, characterized in that: If the analysis results do not meet the design requirements, the blade profile is iteratively designed until the design requirements are met. The steps include: If the analysis result does not meet the design requirements, return to step S01 to re-perform iterative blade design and numerical analysis; In the process of iterative design, a macro is recorded for the process of step S02, and the execution of step S02 in the iterative design is realized through the macro.

7. The method for designing a guide vane for a rear casing according to claim 1, characterized in that: The rear casing guide vanes include engine rear casing guide vanes and gas turbine rear casing guide vanes. The steps of performing variable operating condition analysis on the blade profiles that meet the design requirements include: For the engine rear casing guide vanes that meet the design requirements, calculation and analysis of the blade profile's angle of attack characteristics, Mach number characteristics, and Reynolds characteristics are performed; The angle of attack characteristics and Mach number characteristics of the gas turbine rear casing guide vane that meets the design requirements are calculated and analyzed.

8. A rear casing guide vane, characterized in that: The rear casing guide vane is obtained according to the rear casing guide vane design method according to any one of claims 1-7.

9. A rear casing guide vane, characterized in that: The rear casing guide vane is used for a rear casing whose inlet airflow angle deviates from the axial direction by 20° to 30°; The rear casing guide vane is asymmetrical, and the maximum thickness position of the rear casing guide vane is within the range of 0.2 to 0.3 of the axial chord length.

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