Aero-engine blade flow field analysis method based on multiple reference frames

Abstract

This invention relates to a method for analyzing the flow field of aero-engine blades based on multiple reference frames. The invention includes constructing a flow field model of the aero-engine fan blade using DesignModeler software; meshing the flow field using Fluent Meshing software; setting the MRF method and calculation method; setting boundary conditions for specific operating conditions; and post-processing the calculation results using Tecplot software. This invention can not only convert unsteady flow in the blade flow field into steady flow, but also accurately extract gas state parameters from three-dimensional point coordinates. This invention effectively saves computational costs and time, significantly improves computational efficiency, and has strong engineering application value.

Description

Technical Field

[0001] This invention relates to the field of fluid dynamics simulation technology, and in particular to a method for analyzing the flow field of aero-engine blades based on multiple reference frames. Background Technology

[0002] Aero-engines are highly complex and precise controllable thermodynamic power machines, considered the crown jewel of modern industry and often referred to as the "heart" of aircraft. The safety and reliability of an engine directly determine a series of core performance characteristics of an aircraft, including flight speed, maneuverability, and payload. Aero-engine blades are core components, operating in complex environments of high temperature, high pressure, and high-speed rotation; their performance directly affects the safety of the entire engine. Furthermore, compared to other parts, engine blades have higher manufacturing and maintenance costs. Conducting blade flow field simulation studies can provide crucial data for blade geometry optimization and fluid-structure interaction analysis.

[0003] In recent years, with the rapid development of computer technology, computational fluid dynamics (CFD) has gained increasing attention for its ability to simulate the motion and flow phenomena and processes of various objects in engineering fields through computer numerical simulation to obtain realistic physical effects. This method offers advantages such as good simulation results and low computational cost, and has a broad application market, having been widely used in the field of aerodynamic numerical simulation for aero-engines. However, the conventional two-way fluid-structure interaction method for studying blade flow field changes is computationally expensive, has complex algorithms, and is a transient analysis, making it unsuitable for large-scale research. Furthermore, the continuous rotation of engine rotor blades during operation causes constant changes in their three-dimensional coordinates, hindering the extraction of gas state parameters from the flow field around the blades.

[0004] Currently, two-way fluid-structure interaction methods are commonly used to study blade flow field changes, but these methods are computationally expensive, algorithmically complex, and all are transient analyses. Since aero-engine rotor blades rotate continuously during operation, their three-dimensional coordinates are constantly changing, making it difficult to extract gas state parameters from the flow field around the blades. To facilitate data extraction, the Multi-Reference Frame (MRF) method is used, which simulates the rotational motion of the blades by mimicking the rotation of the airflow. The unsteady flow around the moving component is equated to a steady flow problem in a moving reference frame; therefore, the MRF method is also known as the "frozen rotor method."

[0005] This invention focuses on blades operating in high-speed airflow, achieving a significant improvement in the efficiency of aero-engine blade flow field analysis through technological innovation. It employs a multi-coordinate system method to construct a rotating reference frame, transforming the unsteady rotating flow of the blade into a steady-state flow field calculation, thus greatly reducing computational complexity and resource consumption. Furthermore, by combining data interaction between Fluent and Tecplot software, it enables precise mapping and batch export of three-dimensional spatial point coordinates and gas state parameters, overcoming the bottleneck of parameter extraction under dynamic coordinates of rotating blades. This method shortens the overall calculation cycle while maintaining computational accuracy, providing efficient and reliable data support for blade geometry optimization and fluid-structure interaction analysis. Summary of the Invention

[0006] To address the problem of low computational efficiency in flow field analysis of aero-engine blades under complex environments, this invention provides a multi-reference frame-based flow field analysis method for aero-engine blades. This method not only converts unsteady flow in the blade flow field into steady flow but also accurately extracts gas state parameters from three-dimensional point coordinates. This invention effectively saves computational costs and time, significantly improves computational efficiency, and has strong engineering application value.

[0007] To address the aforementioned technical problems, this invention provides a method for analyzing the flow field of aero-engine blades based on multiple reference frames, comprising: Constructing a flow field model for an aero-engine blade includes: obtaining a geometric model of a single aero-engine blade, the blade geometric model including the blade body and tenon; constructing a fan-shaped fluid domain surrounding the blade body and dividing the fan-shaped fluid domain into a rotating domain and a stationary domain; and simulating blade rotation by rotating the fluid in the rotating domain based on the multiple reference frame (MRF) method. The flow field model is meshed to obtain a mesh model; Based on the aforementioned mesh model, the MRF method and solution settings are implemented to obtain a computational model, including: selecting a turbulence model, defining the fluid material as air and adopting an ideal gas density model, and setting an energy equation that can analyze gas temperature; setting rotational motion in the rotational domain to activate the MRF model, and setting the rotation center, rotation axis, and rotational speed of the rotational domain; setting the interface between the stationary domain and the rotational domain as the interface for cross-regional data transfer; setting the casing wall that rotates with the rotational domain as the moving wall; and using a solution algorithm to perform a comprehensive coupled solution for pressure, velocity, and temperature. Setting operating boundary conditions based on the calculation model includes: calculating the ambient pressure at the corresponding altitude based on the flight altitude, and using the ambient pressure as the operating pressure; setting the boundary types for the inlet and outlet based on known operating environment data and inputting the corresponding boundary data, wherein the boundary data includes gauge pressure data and mass flow rate data; wherein the gauge pressure data is the difference between absolute pressure and atmospheric pressure, and the mass flow rate data is the mass flow rate of a single blade basin, wherein the mass flow rate of a single blade basin is obtained by dividing the total mass flow rate by the number of blades in a ring; After the solution is completed, the calculation results are post-processed.

[0008] In one embodiment of the present invention, the angle θ of the sector watershed model satisfies θ=360° / a, where a is the number of fan blades in a ring.

[0009] In one embodiment of the present invention, the method further includes: dividing the leaf base surface and the leaf back surface of the leaf into different surfaces for subsequent data extraction.

[0010] In one embodiment of the present invention, the flow field model is meshed to obtain a mesh model, including: Given the complex flow field structure near the blade, local mesh sizes are set and mesh refinement is performed at the leading edge, trailing edge, and the entire rotation domain of the blade to improve computational accuracy. Shared topology processing is applied to the interface between the rotating and stationary domains to improve mesh quality and solution efficiency; The two sides of the sector model are set as periodic boundaries to simulate a complete impeller; Define the wall and inlet / outlet types according to the operating conditions, and define the interface between the rotating domain and the stationary domain as the fluid internal surface to ensure the continuity of variables and data transfer across regions. Considering the fluid viscosity effect, a boundary layer mesh is generated on the blade surface; A volume mesh is generated, which adopts the Poly-Hexcore type, and the orthogonality quality of the volume mesh is improved through mesh quality improvement processing.

[0011] In one embodiment of the present invention, the turbulence model is selected as follows: SST k-ω The model, which combines k-ω The model has high accuracy in the near-wall region and k-ε Robustness of the model in free shear flow.

[0012] In one embodiment of the present invention, the rotational speed of the rotational domain is the absolute velocity of the airflow, and the sign of the rotational direction is determined by the right-hand rule.

[0013] In one embodiment of the present invention, the solution algorithm is the Coupled algorithm.

[0014] In one embodiment of the present invention, calculating the ambient pressure at the corresponding altitude based on the flight altitude and using the ambient pressure as the operating pressure includes calculation based on the following formula: ; in, P The environmental pressure at a certain altitude; P 0 represents the atmospheric pressure at an altitude of 0 km, which is usually assumed to be standard atmosphere. P 0 = 101325 Pa; H Altitude; g It is the acceleration due to gravity. g =9.81m / s²; R Let be the gas constant. If the fluid under study is air, take . R =287.06 J / (kg·K); If the fluid under study is the exhaust gas from an aircraft engine, take... R =287.41J / (kg·K).

[0015] In one embodiment of the present invention, post-processing of the calculation results includes: post-processing of the calculation results based on Tecplot software, including: Export the Fluent calculation results file and open it with Tecplot software for post-processing and data extraction. Based on the Tecplot software, different regions were selected for viewing and data export. The exported data was in the form of gas state data in three-dimensional point coordinates. If too much node data is directly exported, the research surface or volume can be sliced ​​using the slices module to export data from one or more slices.

[0016] The technical solution of the present invention has the following advantages compared with the prior art: This invention presents a multi-reference frame flow field analysis method for aero-engine blades, effectively overcoming the difficulty in extracting unsteady flow field and gas state data from existing fluid-structure interaction techniques. The invention uses DesignModeler software to plot the blade flow field, employs Fluent Meshing to mesh the computational domain, uses the multi-reference frame method (MRF) for flow field analysis, and imports the calculation results into Tecplot software for post-processing, batch exporting the gas state parameters of the flow field.

[0017] In flow field analysis, this invention employs the multiple reference frame (MRF) method to divide the computational domain into stationary and rotating regions for analysis. This effectively avoids the complex mesh deformation required for dynamic meshes, significantly improves computational efficiency, and saves computational resources. It simplifies the impeller flow field, improves computational efficiency, and can accurately obtain steady-state flow field data, providing a reliable basis for engineering design and optimization. It is both practical and widely applicable.

[0018] This invention utilizes Tecplot software to batch export gas state parameters of flow fields, significantly improving the efficiency and analytical capabilities of fluid simulation data post-processing. This function allows researchers to directly and accurately extract key physical quantities such as pressure, temperature, and velocity of the fluid at various three-dimensional spatial locations from the calculation results, facilitating subsequent research. The exported parameters can be easily integrated into other analysis platforms or custom programs, supporting chart plotting, comparison, and verification of experimental data, effectively promoting flow mechanism research and engineering optimization. Attached Figure Description

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] Figure 1 This is a flowchart of the flow field analysis method for aero-engine blades based on multiple reference frames according to the present invention.

[0021] Figure 2 This is a diagram of the fan blades and impeller.

[0022] Figure 3 This is a diagram of the computational domain model for a single blade.

[0023] Figure 4 This is a diagram of the complete mesh model.

[0024] Figure 5 This is a partial cross-sectional view of the mesh model.

[0025] Figure 6 This is the average static pressure diagram of the blade surface.

[0026] Figure 7 This is a static pressure cloud map of the blade surface.

[0027] Figure 8 This is a surface temperature cloud map of the blade. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0029] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the convenience of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0030] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0031] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0032] Example 1 Reference Figure 1 As shown, this embodiment provides a flow field analysis method for aero-engine blades based on multiple reference frames. Taking an aero-engine fan blade as an example, there are 18 blades in one ring. Fan blades face complex environments such as high-altitude cruise, takeoff, and landing, and the flow field environment varies under different conditions. How to effectively simulate the flow field environment of the blades under various operating conditions is a key technical challenge in simulation calculations.

[0033] This method includes: constructing a flow field model of an aero-engine fan blade using DesignModeler software; meshing the flow field using Fluent Meshing software; setting the MRF method and calculation method; setting boundary conditions for specific operating conditions; and post-processing the calculation results using Tecplot software. The specific implementation method is as follows: S1. Construct a flow field model for aero-engine fan blades based on DesignModeler software; S1-1. Obtain the geometric model of a single blade of an aero-engine. Import the single blade model into the DesignModeler software. The blade includes the blade body and the tenon.

[0034] S1-2. Draw the fan-shaped fluid domain using commands such as rotation and stretching. The fluid domain only surrounds the blade portion. The angle of the fan-shaped fluid domain model is... θ The leaf base and leaf back are named separately to facilitate data extraction later.

[0035] The angle of the sector watershed model is: θ satisfy: θ =360 o / a ; In the formula: a This refers to the number of blades in a single-ring fan.

[0036] S1-3. Based on the drawn fluid domain, the rotating domain and the stationary domain are divided. The MRF method simulates the blade rotation by the fluid rotation in the rotating domain.

[0037] S2. The flow field model is meshed using Fluent Meshing software to obtain a mesh model.

[0038] S2-1. Due to the complex flow field near the blade, local mesh sizes are added to the leading and trailing edges of the blade and the entire rotation domain to refine the mesh and improve calculation accuracy.

[0039] S2-2. Based on the Apply Share Topology module, the topology of the interface between the rotating domain and the stationary domain is shared to improve the quality of the mesh and the solution efficiency.

[0040] S2-3. Based on the Set Up Periodic Boundaries module, the two sides of the sector model are set as periodic boundaries to simulate a complete impeller.

[0041] S2-4. Define boundary surface types. Define the wall and inlet / outlet types according to objective operating conditions. The interface between the rotating and stationary domains should be defined as the internal surface of the fluid to avoid data transmission problems.

[0042] S2-5. Based on the fluid viscosity, add a boundary layer to the blade surface using the Add Boundary Layers module.

[0043] S2-6. Use a volume mesh of type Poly-Hexcore and improve the mesh orthogonality quality using the Improve Volume Mesh module.

[0044] S3. Based on the mesh model, perform the MRF method and solution settings to obtain the computational model.

[0045] S3-1, Select the turbulence model as SST k-ω Model, combined k-ωThe model has high accuracy in the near-wall region and k-ε Robustness of the model in free shear flow.

[0046] S3-2. Considering gas compressibility, the ideal gas density model (air density model) of the fluid material is defined based on the Materials module. The gas temperature can be analyzed by opening the energy equation.

[0047] S3-3. Based on the Cell Zone Conditions module, set the Frame Motion of the rotation domain and activate the MRF model. Set the rotation center and axis of the rotation domain, and the Rotational Velocity Speed. The speed is the absolute velocity of the airflow, and the sign follows the right-hand rule.

[0048] S3-4. Based on the Mesh Interface module, the interface between the static domain and the rotated domain is set as an Interface. The Interface can handle data transfer between different regions in a multi-region computation model.

[0049] S3-4. The fan housing wall will rotate with the rotation domain. In the Boundary Conditions, the wall module sets the fan housing to Moving Wall.

[0050] S3-5 employs the Coupled algorithm, which solves for pressure, velocity, and temperature simultaneously. This algorithm is suitable for high Mach number compressible flows, especially complex flow problems involving shock waves and strong coupling effects, such as the simulation of airflow inside jet engines. Its advantages include fast convergence speed and high computational accuracy; however, its computational cost is relatively high.

[0051] S4, Setting Boundary Conditions for Specific Operating Conditions.

[0052] S4-1. Set the operating pressure based on the aircraft's flight altitude. The ambient pressure is calculated as the operating pressure using the flight altitude, and the calculation formula is as follows: ; in, P The environmental pressure at a certain altitude; P 0 represents the atmospheric pressure at an altitude of 0 km, which is usually assumed to be standard atmosphere. P 0 = 101325 Pa; H Altitude; g It is the acceleration due to gravity. g =9.81m / s²; R Let be the gas constant. If the fluid under study is air, take . R=287.06 J / (kg·K); If the fluid under study is the exhaust gas from an aircraft engine, take... R =287.41J / (kg·K).

[0053] S4-2. Based on the known operating environment data, set the inlet and outlet types and input the data. For example, the inlet is pressure-inlet and the outlet is mass-flow-outlet.

[0054] S4-3. Gauge pressure data is the difference between absolute pressure and atmospheric pressure; mass flow rate data should be the mass flow rate of a single blade basin, which is the total mass flow rate divided by the number of blades in a ring.

[0055] S5. Post-processing of calculation results based on Tecplot software.

[0056] S5-1. Export the Fluent calculation result file and open it with Tecplot software for post-processing and data extraction.

[0057] S5-2. Using Tecplot software, different regions can be selected to view and export data. There are three methods for exporting data: File—Write Data; Data—Data Set Information; Tools—Write Data As TextFile. The exported data is in the form of gas state data in three-dimensional point coordinates.

[0058] S5-3. Directly exporting too much node data is problematic. The slices module is used to slice the research surface or volume, allowing the export of data for one or more slices (tangents).

[0059] S5-4. If the required data is not found in Tecplot, it can be calculated using the Calculate Variables function in the analyze module of the main menu.

[0060] Example 2 This embodiment uses an aero-engine fan blade as an example. One ring of fan blades has 18 blades. Figure 2 As shown. A single leaf is selected for analysis.

[0061] First, import the 3D model of the blade into DesignModeler software. Then, using commands such as rotation and stretching, draw the 20mm diameter of the blade. o The sector-based fluid domain serves as the computational domain for subsequent research, such as... Figure 3As shown. The computational domain is divided into a rotating domain and a stationary domain. The computational domain model is imported into Fluent Meshing software, and the mesh is refined for the leading and trailing edges of the blade and the rotating domain. The interface quality between the rotating and stationary domains is improved by sharing topology. Periodic boundaries are set to simulate the complete impeller. The boundary surface type is defined and a boundary layer is added. A Poly-Hexcore type volume mesh is selected to improve orthogonality quality, such as... Figure 4 , Figure 5 As shown.

[0062] When performing simulation calculations, select SST k-ω A turbulence model was used, defining air as an ideal gas and opening the energy equations. The MRF model was activated by setting a rotating domain with Frame Motion, defining the interface between the stationary and rotating domains as the Interface, and setting the fan casing as the Moving Wall. The Coupled algorithm was used to solve for the compressible flow. The calculation conditions are shown in Table 1. Atmospheric pressure was calculated based on the flight altitude as the ambient pressure, with an altitude of 0 km and ambient pressure at standard atmospheres. P 0 = 101325 Pa. The inlet is set to mass-flow-inlet, and the outlet to pressure-outlet. The gauge pressure is 7675 Pa. The mass flow rate of a single blade is the total flow rate divided by the number of blades; the input mass flow rate is 12.167 kg / s. The average static pressure on the blade surface is iteratively calculated and monitored. As the number of calculation steps increases, the average static pressure value tends to stabilize, which can be considered as calculation convergence. Figure 6 As shown.

[0063] Table 1 Calculation Conditions

[0064] Exporting Fluent calculation results files to Tecplot software can export static pressure and temperature contour plots, such as... Figure 7 , Figure 8 As shown in the figure. The slices module is used to cut the studied area, making it easier to extract small portions or key data. If the Tecplot software does not find the required parameters, the Calculate Variables function in the Analyze module of the menu can calculate gas state parameters such as pressure, temperature, and velocity at three-dimensional point coordinates. The data export format is shown in Table 2.

[0065] Exporting Partial Data from Table 2

[0066] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0067] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0068] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0069] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0070] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for analyzing the flow field of aero-engine blades based on multiple reference frames, characterized in that, include: Constructing a flow field model for an aero-engine blade includes: obtaining a geometric model of a single aero-engine blade, the blade geometric model including the blade body and tenon; constructing a fan-shaped fluid domain surrounding the blade body and dividing the fan-shaped fluid domain into a rotating domain and a stationary domain; and simulating blade rotation by rotating the fluid in the rotating domain based on the multiple reference frame (MRF) method. The flow field model is meshed to obtain a mesh model; Based on the aforementioned mesh model, the MRF method and solution settings are implemented to obtain a computational model, including: selecting a turbulence model, defining the fluid material as air and adopting an ideal gas density model, and setting an energy equation that can analyze gas temperature; setting rotational motion in the rotational domain to activate the MRF model, and setting the rotation center, rotation axis, and rotational speed of the rotational domain; setting the interface between the stationary domain and the rotational domain as the interface for cross-regional data transfer; setting the casing wall that rotates with the rotational domain as the moving wall; and using a solution algorithm to perform a comprehensive coupled solution for pressure, velocity, and temperature. Setting operating boundary conditions based on the calculation model includes: calculating the ambient pressure at the corresponding altitude based on the flight altitude, and using the ambient pressure as the operating pressure; setting the boundary types for the inlet and outlet based on known operating environment data and inputting the corresponding boundary data, wherein the boundary data includes gauge pressure data and mass flow rate data; wherein the gauge pressure data is the difference between absolute pressure and atmospheric pressure, and the mass flow rate data is the mass flow rate of a single blade basin, wherein the mass flow rate of a single blade basin is obtained by dividing the total mass flow rate by the number of blades in a ring; After the solution is completed, the calculation results are post-processed.

2. The method for analyzing the flow field of aero-engine blades based on multiple reference frames according to claim 1, characterized in that, The angle θ of the sector watershed model satisfies θ=360° / a, where a is the number of fan blades in one ring.

3. The method for analyzing the flow field of aero-engine blades based on multiple reference frames according to claim 1, characterized in that, Also includes: The leaf base surface and the leaf back surface of the blade are divided and named as different surfaces for subsequent data extraction.

4. The method for analyzing the flow field of aero-engine blades based on multiple reference frames according to claim 1, characterized in that, The flow field model is meshed to obtain a mesh model, including: Given the complex flow field structure near the blade, local mesh sizes are set and mesh refinement is performed at the leading edge, trailing edge, and the entire rotation domain of the blade to improve computational accuracy. Shared topology processing is applied to the interface between the rotating and stationary domains to improve mesh quality and solution efficiency; The two sides of the sector model are set as periodic boundaries to simulate a complete impeller; Define the wall and inlet / outlet types according to the operating conditions, and define the interface between the rotating domain and the stationary domain as the fluid internal surface to ensure the continuity of variables and data transfer across regions. Considering the fluid viscosity effect, a boundary layer mesh is generated on the blade surface; Generate a volume mesh using the Poly-Hexcore type and improve the orthogonality quality of the volume mesh.

5. The method for analyzing the flow field of aero-engine blades based on multiple reference frames according to claim 1, characterized in that, Selecting the turbulence model as SST k-ω The model, which combines k-ω The model has high accuracy in the near-wall region and k-ε Robustness of the model in free shear flow.

6. The method for analyzing the flow field of aero-engine blades based on multiple reference frames according to claim 1, characterized in that, The rotational speed of the rotational domain is the absolute velocity of the airflow, and the sign of the rotation direction is determined by the right-hand rule.

7. The method for analyzing the flow field of aero-engine blades based on multiple reference frames according to claim 1, characterized in that, The solution algorithm used is the Coupled algorithm.

8. The method for analyzing the flow field of aero-engine blades based on multiple reference frames according to claim 1, characterized in that, Calculate the ambient pressure at the corresponding altitude based on the flight altitude, and use the ambient pressure as the operating pressure, including calculations based on the following formula: ； in, P The environmental pressure at a certain altitude; P 0 represents the atmospheric pressure at an altitude of 0 km, which is usually assumed to be standard atmosphere. P 0 = 101325 Pa; H Altitude; g It is the acceleration due to gravity. g =9.81m / s²; R Let be the gas constant; if the fluid under study is air, take . R =287.06 J / (kg·K); If the fluid under study is the exhaust gas from an aircraft engine, take... R =287.41J / (kg·K).

9. The method for analyzing the flow field of aero-engine blades based on multiple reference frames according to claim 1, characterized in that, Post-processing of the calculation results includes: post-processing of the calculation results based on Tecplot software, including: Export the Fluent calculation results file and open it with Tecplot software for post-processing and data extraction. Based on the Tecplot software, different regions were selected for viewing and data export. The exported data was in the form of gas state data in three-dimensional point coordinates. If too much node data is directly exported, the research surface or volume can be sliced ​​using the slices module to export data from one or more slices.

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