A passage integrated design method for an axial flow blade of an aero-engine

Abstract

The application relates to a passage integrated design method for an axial flow blade of an aero-engine, and belongs to the technical field of aero-engine aerodynamic design. The method can couple and control the passage integrated design of the blade, an end wall and an angle area. Starting from passage geometric characteristics, non-dimensional conversion is carried out; control points, virtual control points and local deformation domains are regularly constructed in the non-dimensional flow field; the extended free deformation technology is used to carry out integrated control; the flow field after the control is converted into a three-dimensional Cartesian coordinate system again, so that the integrated design of the blade, the end wall and the angle area is realized. The application can ensure that the end wall can still meet the periodicity requirement after the control, solves the limitation that the end wall cannot be included in the deformation domain during the deformation of the traditional free deformation technology, provides a larger design space for the full three-dimensional design of the passage, and can improve the design efficiency of the axial flow fan, the compressor and the turbine.

Description

Technical Field

[0001] This invention relates to an integrated channel design method for axial flow blades of aero-engines, and more particularly to a three-dimensional blade design method for integrated control of the axial flow fan, compressor and turbine in three-dimensional channels, belonging to the field of aero-engine aerodynamic design technology. Background Technology

[0002] Aerodynamic design of aero-engines is a crucial aspect of the development of advanced aero-engines. Influenced by the development of traditional simulation tools and advancements in design technology, aero-engine axial blades exhibit a "pseudo" full three-dimensional design characteristic, combining "two-dimensional blade structure" with "swept and curved spanwise stacking control." Although this design method appears to encompass three design directions, the simple superposition of design dimensions and the independent control of the blade, endwall, and corner regions inevitably lead to certain omissions in the design space.

[0003] To address the shortcomings of traditional aerodynamic design systems, passive control technologies have gained widespread attention for various flow problems. Among these, non-axisymmetric endwall technology aimed at controlling the intensity of lateral secondary flow in the end region and blade / endwall fusion technology for controlling boundary layer convergence in the corner region demonstrate a trend towards elliptical channels in traditional blade passages, highlighting the increasing demand for integrated design of blades, endwalls, and corner regions.

[0004] However, current parametric construction methods for aero-engine aerodynamic design cannot achieve integrated design across the entire aero-engine channel. The key issue in integrated channel design is how to leverage advanced computer-aided graphics methods, combined with the spatial distribution characteristics of aero-engine axial flow blades, to achieve integrated coupling and control of the blades, endwalls, and corner regions. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical defects of traditional axial fan, compressor and turbine aerodynamic design system, which has weak correlation between blade, endwall and corner area design, resulting in omission of design space and low design efficiency. Based on the geometric characteristics of axial flow aero-engine blades, this invention creatively proposes an integrated channel design method for aero-engine axial flow blades.

[0006] This method enables the integrated design of the blade, endwall, and corner regions through a coupled control system. Starting from the geometric characteristics of the channels, a dimensionless transformation is performed. Within this dimensionless flow domain, control points, virtual control points, and local deformation domains are systematically constructed, and integrated control is achieved using extended free deformation technology. The controlled flow domain is then transformed back into a three-dimensional Cartesian coordinate system, realizing the integrated design of the blade, endwall, and corner regions.

[0007] Beneficial effects

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] 1. This invention enables the full three-dimensional integrated design of blades, endwalls, and corner regions, a function that traditional parameterization methods for axial flow blades of aero-engines do not possess;

[0010] 2. This invention can ensure that the end wall can still meet the periodicity requirements after adjustment, and solves the limitation that the end wall cannot be included in the deformation domain during deformation in traditional free deformation technology;

[0011] 3. This invention provides greater design space for the full three-dimensional design of channels, which can improve the design efficiency of axial fans, compressors and turbines. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the blade channel grid in an embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of the geometry to be controlled in an embodiment of the present invention;

[0014] Figure 3 It is the periodic boundary grid in the embodiments of the present invention;

[0015] Figure 4 This is a schematic diagram of the meridional flow path in an embodiment of the present invention;

[0016] Figure 5 This is a schematic diagram of a dimensionless channel in an embodiment of the present invention;

[0017] Figure 6 This is a schematic diagram of control points, virtual control points, and sub-deformation domains in an embodiment of the present invention;

[0018] Figure 7 This is a schematic diagram of control point regulation in an embodiment of the present invention;

[0019] Figure 8 This is a schematic diagram of the integrated design result in the dimensionless coordinate system in an embodiment of the present invention;

[0020] Figure 9 This is a schematic diagram of the integrated design result in an embodiment of the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] An integrated channel design method for axial flow blades of aero-engines includes the following steps:

[0023] Step 1: Input data preparation and checking.

[0024] The required input data includes: blade channel mesh, geometric coordinates to be controlled, and axial starting position coordinates z of the deformation domain. s , Coordinates of the axial end position of the deformation domain z e Number of control points in the axial direction i all Number of control points in the radial direction, j all Number of control points in the circumferential direction, k all , and (i all -2)×(j all -1)×(k all -1)×3 perturbations.

[0025] The input data to be checked includes: the blade channel grid must be periodic, and both the hub and the casing must be axisymmetric structures; the geometric coordinates to be adjusted must be located inside the blade channel grid; and the blade must be completely placed inside the axial start and end positions of the deformation domain.

[0026] Step 2: Extract the periodic surface and meridional flow path.

[0027] Specifically, periodic surface meshes are extracted based on the blade channel mesh. Given the periodicity of the channel mesh and the axisymmetric hub and casing structure, the circumferential position of the periodic surface mesh is a function of its axial and radial positions, i.e.: θ p1 =f(z,r),θ p2 =θ p1 +p, where θ represents the circumferential position, z represents the axial position, r represents the radial position, and p represents the grid pitch. p1 Indicates the first periodic surface, subscript p2 Let f represent the second periodic surface, and let f represent the functional relationship calculated using linear interpolation.

[0028] Meridian flow paths are extracted based on the blade channel mesh. Under the premise of an axisymmetric hub and casing structure, the radial position of the hub and casing is a function of the axial position, i.e., r... h =g(z), r s =h(z), where the subscript h represents the hub, the subscript s represents the casing, and g and h represent a functional relationship that is calculated using linear interpolation.

[0029] Step 3: Dimensionless processing of the channel.

[0030] Specifically, for each internal node of the blade channel mesh, its coordinates are recorded as (r now θ now , z now ), r now θ now z now These represent its radial, circumferential, and axial coordinate values, respectively.

[0031] Dimensionless domain transformation using Equation 1:

[0032]

[0033] Where z′, r′, and θ′ represent dimensionless radial, circumferential, and axial coordinate values, respectively; π represents pi.

[0034] After dimensionless processing, the axial range of the channel deformation domain is [0,1], the radial range is [1,2], and the circumferential range is [0,2π].

[0035] Step 4: Generation of control points and virtual control points and processing of sub-deformation domains.

[0036] Specifically, the coordinates of the i-th axial, j-th radial, and k-th circumferential control points are calculated using Equation 2:

[0037]

[0038] Where iall, jall, and kall represent the total number of control points in the axial, radial, and circumferential directions, respectively.

[0039] The number of virtual control points in the axial and radial directions is the same as that of the control points, and their axial and radial coordinates are calculated according to Equation 2. The circumferential number of virtual control points is (k all -1)×2, the circumferential coordinates of the kth virtual control point are calculated using Equation 3:

[0040]

[0041] Here, floor is the floor function.

[0042] For each node within the dimensionless deformation domain, its coordinates are recorded as (z′, r′, θ′). Then its sub-deformation domain is numbered circumferentially as floor[θ′ / 2π / (k all -1)] and floor[θ′ / 2π / (k all -1)]+1, Axial numbering is 1 to i all Radial numbering from 1 to j all All control points, and those circumferentially numbered [floor[θ′ / / 2π / (k all -1)]-1]×2+1 and [floor[θ′ / 2π / (k all -1)]-1]×2+2, Axial numbering is 1 to i all Radial numbering from 1 to j all The local deformation domain is composed of all virtual control points.

[0043] Step 5: Control point adjustment.

[0044] Specifically, among all control points, the control points that can be adjusted include those with axial node numbers ranging from 2 to i. all -1. Radial node numbering range 1 to j all -1. The circumferential node numbering range is 1 to k. all All control points, of which the circumferential node is numbered k. all The control point adjustment is completely consistent with the control point numbered 1 in the circumferential direction. Each control point can be adjusted independently in the axial, radial, and circumferential directions. Therefore, the total number of deformation controls is (i... all -2)×(j all -1)×(k all -1)×3.

[0045] Based on the input data, the position of each control point is adjusted sequentially to achieve control point regulation.

[0046] Step 6: Adjust the virtual control points.

[0047] All virtual control point positions can be changed, but there is no input data control. Instead, the changes should be made according to the control point positions. In principle, the slope of the curve formed by the virtual control points at each control point should remain unchanged.

[0048] In terms of spatial distribution, the virtual control points at both ends of the control point with circumferential number k are numbered (k-1)×2-1 and (k-1)×2+1 respectively. If k=1, then the virtual control points at both ends are numbered 1 and (k-1)×2+1 respectively. all -1)×2. After the position adjustment of the control point is completed, let its axial, radial and circumferential deformations be Δz, Δr and Δθ respectively. Then the axial, radial and circumferential deformations of the virtual control points at both ends are Δz, Δr and Δθ respectively.

[0049] Step 7: Calculate the dimensionless coordinates of the geometric nodes to be controlled.

[0050] The dimensionless coordinates corresponding to each node in the geometry to be controlled are calculated again according to Equation 1, and denoted as (u, / v, / w), where u is the dimensionless coordinate in the axial direction, v is the dimensionless coordinate in the radial direction, and w is the dimensionless coordinate in the circumferential direction.

[0051] Step 8: Spatial position adjustment of the geometric nodes to be adjusted.

[0052] Calculate its spatial position after adjustment at the control point and virtual control point according to Equation 4:

[0053]

[0054] Where vector Q represents the coordinates of the control point and virtual control point in the sub-deformation domain, and vector X represents the adjusted spatial coordinates, both containing components in the axial, radial, and circumferential dimensions, denoted as (z... n , / r n , / θ n l, m, and n represent the total number of control points in the axial, radial, and circumferential directions minus 1, respectively.

[0055] Let the dimensionless coordinates of the geometric node to be controlled be (u, / v, / w). Then the vector Q with k = 0 corresponds to the circumferential label floor[w / 2π / (k all -1)] control point, k=1 corresponds to the circumferential label [floor[w / 2π / (k all -1)]-1]×2+1 virtual control points, k=2 corresponding to the circumferential label [floor[w / 2π / (k all -1)]-1]×2+2 virtual control points, k=3 corresponding to the circumferential label floor[w / / 2π / (k all -1)]+1 control points.

[0056] Step 9: Dimensional restoration of the spatial control position of the geometric node to be controlled.

[0057] Specifically, the dimensional reconstruction of the coordinates is completed according to Equation 5:

[0058]

[0059] Among them, (z c r c θ c ) represents the coordinates of the geometric node to be controlled in the three-dimensional Cartesian coordinate system after integrated control, and its components represent the axial, radial and circumferential dimensions, respectively. e Represents the minimum value of the axial coordinate, z s This indicates the maximum value of the axial coordinate.

[0060] Furthermore, step 10 is included, which verifies the continuity and periodicity of the integrated design. Specifically, after completing the integrated control of all channels of the geometry to be controlled, the continuity and periodicity of the deformation results are checked in the three-dimensional Cartesian coordinate system. If there are any abnormalities in the results, the relevant application of Equation 1 is carefully checked. Under the premise of proper use, both continuity and periodicity should meet the requirements of engineering applications.

[0061] Example

[0062] This example describes a specific implementation scheme of the channel integration design method for axial flow blades of aero-engines described in this invention.

[0063] This embodiment applies to the Rotor 67, a low aspect ratio transonic fan blade designed by NASA in the 1970s. Its design tip relative Mach number is 1.38, design pressure ratio is 1.63, and design flow rate is 33.25 kg / s. According to the implementation steps of this invention, the initial state is... Figure 1 The Rotor 67 channel adopts an integrated channel design, and the specific implementation steps are as follows:

[0064] First, read in the input data, which includes the blade channel mesh ( Figure 1 ), Geometric coordinates to be adjusted Figure 2 ), the axial starting position coordinates of the deformation domain z s = -0.1 meters, coordinates of the axial end position of the deformation domain z e = 0.4 meters, number of control points in the axial direction i all =15, Number of control points in the radial direction j all =9. Number of control points in the circumferential direction, k all =8,2184 disturbances.

[0065] based on Figure 2 The Rotor 67-channel mesh shown is used to extract the periodic surface mesh and meridional flow path, which are then displayed in [the image / database]. Figure 3 and Figure 4 .

[0066] Dimensionless processing was performed on the entire channel mesh and the geometry to be controlled. The spatial positions of the hub, casing, blades, and periodic planes in the processed channel mesh are shown below. Figure 5 .

[0067] Control points and virtual control points are generated in a dimensionless coordinate system, and the sub-deformation domain corresponding to the geometric node to be controlled is determined based on the position of the node. Figure 6 The diagram shows control points, virtual control points, and sub-deformation domains.

[0068] Based on the 2184 disturbances read in, the control point positions are adjusted sequentially and the virtual control point positions are updated accordingly. The adjusted control points are shown below. Figure 7 Medium purple solid point.

[0069] Based on the adjusted control points, the spatial positions of the geometric nodes to be adjusted are recalculated. The calculation results are shown below. Figure 8 .

[0070] The geometric entity after the integrated channel design was restored to a three-dimensional Cartesian coordinate system, and the continuity of the grid lines and the periodicity between the leaf rows were checked. The results are shown in […]. Figure 9 .

[0071] The above description is merely an illustrative embodiment of the present invention, and the present invention should not be limited to the content disclosed in this embodiment and the accompanying drawings. Any equivalent or modified versions made without departing from the spirit of the present invention fall within the protection scope of the present invention.

Claims

1. A method for integrated channel design of axial flow blades for aero-engines, characterized in that, Includes the following steps: Step 1: Input data preparation and checking; The required input data includes: blade channel mesh, geometric coordinates to be adjusted, and axial starting position coordinates z of the deformation domain. s , Coordinates of the axial end position of the deformation domain z e Number of control points in the axial direction i all Number of control points in the radial direction, j all Number of control points in the circumferential direction, k all , and (i all -2)×(j all -1)×(k all -1)×3 perturbations; Step 2: Extract the periodic surface and meridional flow path; Periodic surface meshes are extracted based on the blade channel mesh. Given the periodicity of the channel mesh and the axisymmetric hub and casing structure, the circumferential position of the periodic surface mesh is a function of its axial and radial positions, i.e.: θ p1 =f(z,r), θ p2 =θ p1 +p, where θ represents the circumferential position, z represents the axial position, r represents the radial position, and p represents the grid pitch. p1 Indicates the first periodic surface, subscript p2 Let f represent the second periodic surface, and let f represent the functional relationship calculated using linear interpolation. Meridian flow paths are extracted based on the blade channel mesh; under the premise of axisymmetric hub and casing structure, the radial position of the hub and casing is a function of the axial position, i.e., r h =g(z), r s =h(z), where the subscript h represents the hub, the subscript s represents the casing, and g and h represent a functional relationship calculated using linear interpolation; Step 3: Dimensionless processing of the channel; For each internal node of the blade channel mesh, its coordinates are recorded as (r now θ now , z now ), r now、 θ now、 z now These represent its radial, circumferential, and axial coordinate values, respectively. Dimensionless domain transformation using Equation 1: （1） in, , , These represent the dimensionless radial, circumferential, and axial coordinate values, respectively; π represents pi (the mathematical constant for a circle). Step 4: Generation of control points and virtual control points, and processing of sub-deformation domains; The coordinates of the i-th control point in the axial direction, the j-th control point in the radial direction, and the k-th control point in the circumferential direction are calculated using Equation 2: （2） in, , , These represent the total number of control points in the axial, radial, and circumferential directions, respectively. The number of virtual control points in the axial and radial directions is the same as that of the control points, and their axial and radial coordinates are calculated according to Equation 2; the number of virtual control points in the circumference is (k all -1)×2, the circumferential coordinates of the kth virtual control point are calculated using Equation 3: （3） Where floor is the floor function; For each node within the dimensionless deformation domain, its coordinates are recorded as ( , If ), then its sub-deformation domain is circumferentially numbered floor[ / 2π / (k all -1)] and floor[ / 2π / (k all -1)]+1, Axial numbering is 1 to i all Radial numbering from 1 to j all All control points, and those circumferentially numbered [floor[ / 2π / (k all -1)]-1]×2+1 and [floor[ / 2π / (k all -1)]-1]×2+2, Axial numbering is 1 to i all Radial numbering from 1 to j all The local deformation domain composed of all virtual control points; Step 5: Control point adjustment; Of all control points, the control points that can be adjusted include those with axial node numbers ranging from 2 to i. all -1. Radial node numbering range 1 to j all -1. The circumferential node numbering range is 1 to k. all All control points, of which the circumferential node is numbered k. all The control point adjustment is completely consistent with the control point numbered 1 in the circumferential direction; the adjustment of each control point can be performed independently in the axial, radial, and circumferential directions; the total number of deformation control points is (i all -2)×(j all -1)×(k all -1)×3; Based on the input data, the position of each control point is adjusted sequentially to achieve control point regulation; Step 6: Adjust the virtual control points; In terms of spatial distribution, the virtual control points at both ends of the control point with circumferential number k are numbered (k-1)×2-1 and (k-1)×2+1 respectively. If k=1, then the virtual control points at both ends are numbered 1 and (k-1)×2+1 respectively. all -1)×2; After the position adjustment of the control point is completed, its axial, radial and circumferential deformations are Δz, Δr and Δθ respectively. Then the axial, radial and circumferential deformations of the virtual control points at both ends are Δz, Δr and Δθ respectively. Step 7: Calculate the dimensionless coordinates of the geometric nodes to be controlled; The dimensionless coordinates corresponding to each node in the geometry to be controlled are calculated again according to Equation 1, and denoted as (u, v, w), where u is the dimensionless coordinate in the axial direction, v is the dimensionless coordinate in the radial direction, and w is the dimensionless coordinate in the circumferential direction. Step 8: Spatial position adjustment of the geometric nodes to be adjusted; Calculate its spatial position after adjustment at the control point and virtual control point according to Equation 4: （4） Where vector Q represents the coordinates of the control point and virtual control point in the sub-deformation domain, and vector X represents the adjusted spatial coordinates, both containing components in the axial, radial, and circumferential dimensions, denoted as (z... n , r n , θ n ); , , These represent the total number of control points in the axial, radial, and circumferential directions minus 1, respectively. Let the dimensionless coordinates of the geometric node to be controlled be (u, v, w). Then the vector Q labeled k=0 corresponds to the circumferential label floor[w / 2π / (k all -1)] control point, k=1 corresponds to the circumferential label [floor[w / 2π / (k all -1)]-1]×2+1 virtual control points, k=2 corresponding to the circumferential label [floor[w / 2π / (k all -1)]-1]×2+2 virtual control points, k=3 corresponding to the circumferential label floor[w / 2π / (k all Control points of -1)]+1; Step 9: Dimensional restoration of the spatial control position of the geometric nodes to be controlled; Based on Equation 5, complete the dimensional reconstruction of the coordinates: （5） Among them, (z) c r c θ c ) represents the coordinates of the geometric node to be controlled in the three-dimensional Cartesian coordinate system after integrated control, and its components represent the axial, radial and circumferential dimension coordinates respectively.

2. The integrated channel design method for axial flow blades of aero-engines as described in claim 1, characterized in that, In step 1, the input data to be checked includes: the blade channel mesh must be periodic, and both the hub and the casing must be axisymmetric structures; the geometric coordinates to be adjusted must be located inside the blade channel mesh; and the blade must be completely placed inside the axial start and end positions of the deformation domain.

3. The integrated channel design method for axial flow blades of aero-engines as described in claim 1, characterized in that, In step 3, after dimensionless processing, the axial range of the channel deformation domain is [0,1], the radial range is [1,2], and the circumferential range is [0,2π].

4. The integrated channel design method for axial flow blades of aero-engines as described in claim 1, characterized in that, This includes step 10, which involves conducting continuity and periodicity checks on the integrated design.

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