A modeling method for coupling blade root rounding and non-axisymmetric end wall of compressor

Abstract

The present invention discloses a compressor coupling blade root rounding and non-axisymmetric end wall modeling method, which belongs to the field of compressor design; the method steps are: simulating and calculating the compressor numerical model to obtain the position of the corner zone separation; constructing the blade root rounding circumferential curve of the compressor blade; constructing the blade root rounding spanwise profile of the compressor blade; determining the blade root rounding thickness distribution of the compressor blade, and then obtaining the blade root rounding modeling; establishing the end wall circumferential curve in the standard space; mapping the end wall circumferential curve in the standard space into the compressor end wall circumferential curve through coordinate transformation, and then fitting to obtain the non-axisymmetric end wall surface; coupling the blade root rounding modeling and the non-axisymmetric end wall surface to generate a compressor flow channel model. The parameterization scheme of coupling the blade root rounding and the non-axisymmetric end wall of the present invention not only makes more accurate modifications to the local modeling, but also further improves the improvement of the airflow loss in the corner area of ​​the compressor.

Description

Technical Field

[0001] The invention belongs to the field of compressor design, and in particular relates to a modeling method for coupling blade root rounding and non-axisymmetric end wall of a compressor. Background Art

[0002] With the continuous development of the aviation industry, aircraft engines require a higher thrust-to-weight ratio, higher efficiency and greater operating margin. While pursuing high engine performance, the single-stage load inside the axial compressor is also increasing, and the reverse pressure gradient and secondary flow intensity of the compressor flow channel are significantly improved, causing the three-dimensional airflow separation phenomenon in the proximal area to become more and more serious. Corner separation will not only affect the normal diffusion process and reduce flow efficiency, but also induce aerodynamic instability, which will seriously harm the operation of aircraft engines. Therefore, adopting advanced flow control modeling to suppress the corner airflow separation phenomenon is one of the current research focuses.

[0003] At present, the flow control of compressor corner separation can be divided into two categories: active control scheme and passive control scheme. For example, active flow control methods such as suction and jet need to use external energy or introduce fluid from the outside to suppress corner separation, and there are many restrictions. Passive control methods include non-axisymmetric end wall, blade root rounding, leading edge shaping and other methods. In previous studies, blade root rounding was first used to control blade root stress and improve blade strength. In flow control, the essence of blade root rounding is to use the dihedral principle to control the migration of low-energy fluid in the corner area. In the prior art, a variety of rounding structures are set for low-speed compressors and numerical simulation studies are conducted. The results show that under stall conditions, the loss reduction is up to 5.22%, but it increases by 1.12% under design conditions. The rounding shape with the best flow control effect reduces the stall factor by 41.29% and enables the blade grid to have a larger angle of attack range. In current research, the flow control of compressor blade root rounding still has some shortcomings: 1. Due to the low degree of freedom of conventional rounding shape, it is difficult to meet the complex multi-condition performance requirements at the same time. 2. The rounded shape suppresses corner separation by reducing the channel vortex and corner vortex strength, but it is difficult to completely remove the low-energy fluid attached to the end wall.

[0004] At present, non-axisymmetric endwalls have many practical engineering applications in axial compressors or turbines, and are an important means to suppress low-energy fluid losses in the proximal area. In the prior art, the hub endwall of the tandem stator blades of the axial compressor is parameterized using Bezier curved surfaces, and an optimization algorithm is introduced to optimize the non-axisymmetric endwall modeling. The results show that the optimized endwall modeling improves the stage efficiency by about 0.5% in all working conditions, and the total pressure ratio is increased by an average of 0.01. When the non-axisymmetric endwall modeling of the high-load subsonic compressor cascade is performed, the optimal modeling significantly reduces the total pressure loss of the cascade under both the design and stall conditions. The non-axisymmetric endwall modeling affects the static pressure gradient distribution of the endwall by changing the convexity and concavity of the wall surface, and generates a driving force that significantly suppresses the secondary flow in the corner area. However, there are still some disadvantages: 1. First, the endwall modeling mainly affects the lateral secondary flow intensity of the endwall, but has little inhibitory effect on the spanwise secondary flow of the blade surface. 2. Excessive convexity or concavity of the endwall modeling will cause a significant change in the cross-sectional area of ​​the flow channel, which will affect the normal expansion process. Summary of the invention

[0005] Technical issues to be solved:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a compressor coupling blade root rounding and non-axisymmetric end wall modeling method, by coupling the blade root rounding and the non-axisymmetric end wall to obtain the compressor flow path modeling, using B-spline curves and cubic functions to fully parameterize the blade root rounding, greatly improving the flexibility and freedom of the rounding modeling; using cubic Fourier functions to parameterize the end wall modeling can ensure that the axial cross-sectional area is constant, avoiding excessive cross-sectional changes that affect the expansion process. The parameterization scheme of coupling the blade root rounding and the non-axisymmetric end wall of the present invention not only makes more precise modifications to the local modeling, but also further improves the degree of improvement of the airflow loss in the corner area of ​​the compressor, and has broad application prospects in the field of internal flow control of aircraft engines.

[0007] The technical solution of the present invention is: a shaping method of coupling blade root rounding and non-axisymmetric end wall of a compressor, wherein each blade of the compressor is evenly distributed on the non-axisymmetric end wall along the circumferential direction; the specific steps are as follows:

[0008] The numerical model of the compressor is simulated and calculated to extract the flow field information under the near-stall condition, and then the position of the angular zone separation is obtained;

[0009] Constructing a blade root rounding circumferential curve of the compressor blade at the position where the corner area is separated;

[0010] Constructing a blade root rounding spanwise profile of the compressor blade at the position where the corner area is separated;

[0011] Based on the blade root rounding circumferential curve and the blade root rounding spanwise profile line of the compressor blade, determining the blade root rounding thickness distribution of the compressor blade, and then obtaining the blade root rounding shape;

[0012] Establish the end wall circumferential curve in the standard space;

[0013] The end wall circumferential curve in the standard space is mapped into the end wall circumferential curve of the compressor through coordinate transformation, and then the non-axisymmetric end wall surface is obtained by fitting;

[0014] The compressor flow channel model is generated by coupling the blade root rounding shape and the non-axisymmetric end wall surface.

[0015] A further technical solution of the present invention is: the flow field information under the near-stall condition is extracted through the compressor corner streamline topology, secondary flow distribution cloud map and dissipation function distribution cloud map.

[0016] A further technical solution of the present invention is: the method for constructing the root rounding circumferential curve of the compressor blade is:

[0017] Two uniform B-spline curves are respectively selected at the corner separation position of the suction surface and the pressure surface of the blade to control the circumferential shape of the inverted circle;

[0018] Set the number of control points and the order of basis functions of the B-spline curve;

[0019] The equation for constructing the B-spline curve is as follows:

[0020]

[0021] in, d i Represents control points i The coordinates of N i,k express k Order B-spline basis function; i Indicates the control point number, k represents the order of the basis function;

[0022] Basis Functions N i,k The recursive formula is used to construct the circumferential curve of the compressor blade root fillet, and the formula is as follows:

[0023]

[0024] in, u i is the basis function node;

[0025] The basis functions of each order are obtained by iterative calculation according to the recursive formula; when the situation of 0 / 0 appears in the recursive process, the numerical ratio is defined as 0.

[0026] A further technical solution of the present invention is: the method for constructing the blade root rounding spanwise profile of the compressor blade is:

[0027] The cubic function is used to construct the blade root fillet span profile, and the specific function equation is:

[0028]

[0029] in, h Indicates the fillet span height; t The value ranges from 0 to 1, reflecting the change in rounding thickness; a, b, c Three coefficients to control the spanwise profile change of blade root rounding; h 叶 Indicates leaf height;

[0030] By Constraint a, b, c The three coefficients ensure smooth contact between the chamfer and the blade, and between the chamfer and the end wall, and prevent sharp edges from appearing in the corner area, which will affect the aerodynamic performance of the model. The specific constraints are:

[0031] .

[0032] A further technical solution of the present invention is: the distribution expression of the rounded thickness of the blade root of the compressor blade is:

[0033]

[0034] in, BS(z) and BP(z) They represent the fillet thickness of the suction side and the pressure side under the control of the B-spline curve respectively; z represents the coordinate of the z-axis.

[0035] A further technical solution of the present invention is: the method for establishing the end wall circumferential curve in the standard space is:

[0036] In the Cartesian coordinate system, a normalized standard space is established, that is, the value ranges of the three directions X, Y, and Z are all [0,1], where X represents the blade span direction, Y represents the channel circumferential direction, and Z represents the channel axial direction;

[0037] At multiple positions evenly spaced in the Z direction, the end wall circumferential curve is established using a third-order Fourier function. At the same time, the fluctuation amplitude of the end wall circumferential curve at the starting position and the end position is guaranteed to be constant at 0; the expression of the end wall circumferential curve is:

[0038]

[0039] in, C m and S m It represents the coefficient that controls the fluctuation of the circumferential curve of the end wall in the standard space. m represents the order of the Fourier function; LIt represents the parameter that controls the maximum fluctuation amplitude of the circumferential curve of the end wall in the standard space, and its value is in the range of 0~1; x 标 , y 标 , z 标 They represent the coordinates of each point on the circumferential curve of the end wall in the standard space; ω represents the coefficient that controls the period of the Fourier curve; j Indicates the serial number of the circumferential curve of the end wall in the standard space on the Z axis.

[0040] A further technical solution of the present invention is: the end wall circumferential curve in the standard space is mapped into the end wall circumferential curve of the compressor through coordinate transformation. When the non-axisymmetric end wall is located on the hub surface, the coordinate mapping equation is:

[0041]

[0042] in, r The root represents the wheel radius corresponding to the current z-axis coordinate. h Leaf means leaf height, θ Pressure represents the angle between the pressure side of the blade and the positive direction of the y-axis; zfront represents the z-axis coordinate of the leading edge of the compressor blade, and ztail represents the z-axis coordinate of the trailing edge of the compressor blade; is the number of flow channel cycles.

[0043] A further technical solution of the present invention is: the end wall circumferential curve in the standard space is mapped into the end wall circumferential curve of the compressor through coordinate transformation. When the non-axisymmetric end wall is located on the casing surface, the coordinate mapping equation is:

[0044]

[0045] in, r 尖 Indicates the casing radius corresponding to the current z-axis coordinate.

[0046] A further technical solution of the present invention is that the height fluctuation of the non-axisymmetric end wall is [-2.5%, 2.5%] h 叶 Varies within range.

[0047] A further technical solution of the present invention is: the compressor flow channel model is structured grid-divided by NUMECA-Autogrid5, and the structured grid is exported.

[0048] Beneficial Effects

[0049] The beneficial effects of the present invention are as follows: the modeling method of the present invention first performs numerical verification and flow field topology analysis on the compressor to effectively determine the angular separation area and range; then the blade root geometry of the compressor model is parameterized, and the circumferential shape of the suction surface and the pressure surface chamfer is controlled by the B-spline curve, which has the advantage of ensuring that the chamfer modeling design has a high degree of freedom; the spanwise change of the suction surface and the pressure surface chamfer is controlled by a cubic function to ensure a continuous and smooth transition between the chamfer and the blade surface; then the third-order Fourier equation is used to control the circumferential end wall fluctuation, construct the end wall circumferential curve, and fit all circumferential curves into a smooth end wall surface, and the end wall concave and convex fluctuation is achieved by changing the coefficients of each trigonometric function in the Fourier equation. The blade root chamfer and the end wall modeling are coupled in a function parameterized form. This method has excellent characteristics such as few modeling parameters, high degree of freedom, and smooth surface transition. After reasonable modeling, the angular separation can be greatly improved and the end area flow loss can be reduced.

[0050] The invention has a high degree of freedom in modeling and is easy to carry out local modification, and is an effective means for solving the complex corner zone separation phenomenon in the compressor. Figure 2 and Figure 3 The parametric modeling schematic diagrams of compressor blade root fillet and non-axisymmetric end wall are shown respectively. By changing the fillet suction and pressure side control line functions, fillet span control line functions, and the third-order Fourier curve function controlling the non-axisymmetric end wall, the modeling method realizes the three-dimensional geometric reconstruction of the end area modeling, which is conducive to the subsequent quantitative analysis of the correlation between local modeling geometry and flow field performance.

[0051] Compared with the previous shaping technologies such as blade root rounding or non-axisymmetric end wall, the present invention has greater flexibility and freedom in shaping with fewer variables. Moreover, the structural shaping of blade root rounding coupled with non-axisymmetric end wall has better improvement capability than the single blade root rounding or non-axisymmetric end wall diagonal area separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of a shaping method of coupling blade root rounding and non-axisymmetric end wall of a compressor in an embodiment of the present invention;

[0053] Figure 2 A schematic diagram of parameterization of the root rounding of a compressor blade in an embodiment of the present invention;

[0054] Figure 3 Schematic diagram of parameterization of a non-axisymmetric end wall of a compressor in an embodiment of the present invention;

[0055] Figure 4 The static pressure coefficient cloud diagram and the limiting streamline topology diagram of the compressor prototype in the embodiment of the present invention are shown;

[0056] Figure 5 The secondary flow distribution cloud diagram of the end area of ​​the compressor prototype in the embodiment of the present invention;

[0057] Figure 6 It is a dissipation function cloud diagram of the compressor prototype in the embodiment of the present invention, and the angular zone separation area;

[0058] Figure 7a Schematic diagram of circumferential parameterized curves of the rounded suction surface and pressure surface of the blade root in an embodiment of the present invention;

[0059] Figure 7b Schematic diagram of the blade root rounding spanwise curve in an embodiment of the present invention;

[0060] Figure 8 A cloud diagram showing the height variation of the non-axisymmetric end wall in an embodiment of the present invention;

[0061] Fig. 9 A geometrical schematic diagram of the coupled shaping of blade root rounding and non-axisymmetric end wall in an embodiment of the present invention;

[0062] Fig.10 The Q-criterion isosurface distributions of the compressor prototype, single modeling structure and coupled modeling structure in the present invention; (a) prototype, (b) single modeling structure-rounding, (c) single modeling structure-non-axisymmetric end wall, (d) blade root rounding and non-axisymmetric end wall coupled modeling. DETAILED DESCRIPTION

[0063] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0064] Based on the low degree of freedom of blade root rounding in the prior art, and the difficulty in completely removing the low-energy fluid attached to the end wall; the non-axisymmetric end wall has a small inhibitory effect on the spanwise secondary flow on the blade surface, or because the end wall shape is too large, the convexity or concaveness will cause a significant change in the cross-sectional area of ​​the flow channel, which will affect the normal expansion process, etc., the present invention provides a compressor coupling blade root rounding and non-axisymmetric end wall shaping method, and the specific steps are as follows:

[0065] Step 1: Simulate the compressor numerical model to extract the flow field information under the near-stall condition, and then obtain the position of the angular zone separation;

[0066] Step 2: constructing a blade root rounding circumferential curve of the compressor blade at the position where the corner area is separated;

[0067] Step 3: constructing a blade root rounding spanwise profile of the compressor blade at the position where the corner area is separated;

[0068] Step 4: Based on the blade root rounding circumferential curve and the blade root rounding spanwise profile line of the compressor blade, determine the blade root rounding thickness distribution of the compressor blade, and then obtain the blade root rounding shape;

[0069] Step 5: Establish the end wall circumferential curve in the standard space;

[0070] Step 6: Map the end wall circumferential curve in the standard space into the end wall circumferential curve of the compressor through coordinate transformation, and then fit the non-axisymmetric end wall surface;

[0071] Step 7: Coupling the blade root fillet shape and the non-axisymmetric end wall surface to generate a compressor flow channel model.

[0072] Compared with the previous modeling technologies such as blade root rounding or non-axisymmetric end wall, the method of the present invention has greater flexibility and freedom in modeling with fewer variables. Moreover, the structural modeling of blade root rounding coupled with non-axisymmetric end wall has better improvement ability than single blade root rounding or non-axisymmetric end wall diagonal area separation.

[0073] The above technical solution is further described below in conjunction with the accompanying drawings:

[0074] Figure 1 This is a technical roadmap of a compressor coupling blade root rounding and non-axisymmetric end wall modeling method in this embodiment. Taking a low-speed and high-load axial flow compressor as an example, the influence of modeling on corner zone separation is analyzed in combination with numerical simulation results. Table 1 shows some design parameters of the low-speed and high-load axial flow compressor.

[0075] Table 1

[0076]

[0077] Taking the compressor as an example, the specific steps of the shaping method of coupling blade root rounding and non-axisymmetric end wall of a compressor in this embodiment are described:

[0078] Step 1: Analyze the compressor model to determine the corner separation area and range;

[0079] Numerical simulation and flow field analysis were performed on the compressor geometry to obtain the corner streamline topology under near-stall conditions ( Figure 4 )、Secondary flow distribution cloud diagram( Figure 5 ) and the dissipation function distribution cloud diagram ( Figure 6 ). From the streamline topology diagram, it is found that the starting point of the corner separation in the near-stall condition is located at the root of the suction side of the leading edge, and gradually expands toward the high blade span with the flow, forming a large range of low-energy fluid groups behind the trailing edge. From the secondary flow energy distribution and dissipation function distribution cloud diagram, it can be found that the secondary flow intensity and dissipation loss gradually increase with the expansion of the corner separation range. Therefore, suppressing the development of corner separation through shaping can effectively improve the flow and reduce flow losses.

[0080] Step 2: constructing a blade root fillet circumferential curve of the compressor blade based on the angular zone separation position determined in step 1;

[0081] Uniform B-spline curves are used on both the suction and pressure surfaces of the blade to control the circumferential changes on both sides of the chamfer. In this embodiment, the number of control points of the curve equation is 6 and the order is 4. Compared with Bezier curves, B-spline curves are more conducive to local modification. Figure 7a The schematic diagram of uniform B-spline control line in standard space is shown, and its equation is:

[0082] (1)

[0083] in d i Represents control points i The coordinates of N i,k represents the k-order B-spline basis function, i It indicates the control point number. k is the order of the basis function, k=2, 3, 4, 5.

[0084] Basis Functions N i,k The Cox-de Boor recursive formula is used to construct the curve:

[0085] (2)

[0086] in, u i is the basis function node. Since uniform B-spline is used, u i+1 - u i It is always a constant value. The basis functions of each order are iteratively calculated according to the recursive formula. When 0 / 0 occurs during the calculation process, the numerical ratio is defined as 0.

[0087] Step 3: constructing the blade root rounding spanwise profile of the compressor blade based on the angular zone separation position determined in step 1;

[0088] A cubic function is used to control the change of the fillet along the blade height, which ensures a smooth connection between the fillet in the corner area and the wall. Figure 7b The distribution of blade root fillet thickness along the span direction is shown, and its specific function equation is:

[0089] (3)

[0090] in, h represents the spanwise height of the fillet, t Reflects the change in fillet thickness, ranging from 0 to 1. a, b, c In order to control the three coefficients of blade root rounding spanwise profile change, by adjusting a, b, cChange the fillet span profile. In addition, to ensure smooth contact between the fillet and the blade and end wall, and to avoid sharp edges in the corner area that affect aerodynamic performance, a, b, c The three coefficients must satisfy the following constraints:

[0091] (4)

[0092] Combining the circumferential curve law of the blade root fillet reflected by equation (1) with the spanwise line law of the blade root fillet reflected by equation (3), the root fillet thickness distribution is obtained:

[0093] (5)

[0094] in, BS(z) and BP(z) They represent the fillet thickness of the suction side and the pressure side under the control of the B-spline curve respectively; z represents the coordinate of the z-axis.

[0095] Step 4: Construct the third-order Fourier end wall circumferential curve in the standard space;

[0096] In the Cartesian coordinate system, a normalized standard space with the value range of X, Y, and Z directions in [0,1] is established, where X represents the blade span direction, Y represents the channel circumferential direction, and Z represents the channel axial direction. In order to improve the flexibility and freedom of the non-axisymmetric end wall modeling, a circumferential curve is established using a third-order Fourier function at six circumferential positions: Z1=0, Z2=0.2, Z3=0.4, Z4=0.6, Z5=0.8, and Z6=1. In order to ensure that the front trailing edge flow channel extension section is smoothly connected to the non-axisymmetric end wall, the fluctuation amplitude of the circumferential curve at the Z=0 and Z=1 positions is constant to 0 ( L =0). The circumferential curve constructed by the third-order Fourier function is expressed as:

[0097] (6)

[0098] In the above formula, C m and S m It represents the coefficient that controls the fluctuation of the circumferential curve of the end wall in the standard space. The fluctuation shape of the curve can be changed by changing the coefficient. m Represents the order of the Fourier function. L It indicates the parameter that controls the maximum fluctuation amplitude of the circumferential curve of the inner end wall of the standard space. It is flexible in the range of 0 to 1. Its function is to control the maximum fluctuation amplitude of the circumferential curve of the standard space. When the value is 0, it is a straight line, and when the value is 1, the fluctuation is the largest. x 标 , y 标 , z 标They represent the coordinates of each point on the circumferential curve of the end wall in the standard space; ω represents the coefficient that controls the period of the Fourier curve; j Indicates the serial number of the circumferential curve of the end wall in the standard space on the Z axis.

[0099] Step 5: Map and fit the standard space curve to the end wall surface;

[0100] The six end wall circumferential curves in the standard space are mapped into the end wall circumferential curves of the compressor through coordinate transformation. When the non-axisymmetric end wall is located on the hub surface, the coordinate mapping equation is:

[0101] (7)

[0102] in, r 根 Indicates the hub radius at this axial position, h 叶 Indicates leaf height, θ 压 Indicates the pressure side of the flow channel and y The angle in the positive direction of the axis. x 标 、y 标 、z 标 Respectively represent the coordinates of each point on the circumferential curve in the standard space. 前 represents the z-axis coordinate of the leading edge of the compressor blade, z 尾 Represents the z-axis coordinate of the trailing edge point of the compressor blade; n 周 is the number of flow channel cycles.

[0103] When the non-axisymmetric end wall is located on the casing surface, the coordinate mapping equation is:

[0104] (8)

[0105] in, r 尖 represents the casing radius at this axial position, and the other parameters are defined in the same way as in formula (7). Figure 8 The height cloud map of the non-axisymmetric end wall shape of the compressor hub surface is displayed.

[0106] The above transformation equation realizes the mapping of the curve in the standard space to the rotation surface, and ensures that the end wall height fluctuation is between [-2.5%, 2.5%] h 叶 Then, the mapped curve is fitted by NUMECA-IGG module to generate a non-axisymmetric end wall surface with smooth transition.

[0107] Step 6: After coupling the blade root rounding shape with the non-axisymmetric end wall (such as Fig. 9 ), the compressor flow path model is structured gridded by NUMECA-Autogrid5, and the structured grid is exported.

[0108] In order to further illustrate the improvement of the aerodynamic performance of the compressor by the blade root rounding and the non-axisymmetric end wall coupling modeling, Table 2 compares the total pressure loss of the prototype, the single modeling structure and the coupled modeling structure under near-stall conditions. After comparison, it is found that the blade root rounding and the non-axisymmetric end wall coupling modeling have the most significant improvement on the total pressure loss, which is 15.2% lower than the prototype loss.

[0109] Table 2

[0110]

[0111] Fig.10 The Q-criterion isosurfaces of the compressor prototype, single modeling structure and coupled modeling structure can identify the vortex structure in the channel. Comparison shows that the coupled modeling has two advantages over the single modeling structure. First, the shear dissipation intensity of the channel vortex is significantly reduced. Second, in the coupled modeling, the trailing edge vortex is almost completely suppressed. At the same time, due to the improvement of the flow in the channel, the intensity of the mixing vortex behind the trailing edge is reduced, which significantly improves the wake mixing dissipation effect. Therefore, the coupled modeling of blade root rounding and non-axisymmetric end wall has greater potential for improving the corner separation of axial flow compressors.

[0112] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A method for coupling blade root rounding with a non-axisymmetric end wall of a compressor, wherein the blades of the compressor are evenly distributed on the non-axisymmetric end wall along the circumferential direction; characterized in that The specific steps are as follows: The numerical model of the compressor is simulated and calculated to extract the flow field information under the near-stall condition, and then the position of the angular zone separation is obtained; Constructing a blade root rounding circumferential curve of the compressor blade at the position where the corner area is separated; Constructing a blade root rounding spanwise profile of the compressor blade at the position where the corner area is separated; Based on the blade root rounding circumferential curve and the blade root rounding spanwise profile line of the compressor blade, determining the blade root rounding thickness distribution of the compressor blade, and then obtaining the blade root rounding shape; Establish the end wall circumferential curve in the standard space; The end wall circumferential curve in the standard space is mapped into the end wall circumferential curve of the compressor through coordinate transformation, and then the non-axisymmetric end wall surface is obtained by fitting; The compressor flow channel model is generated by coupling the blade root rounding and the non-axisymmetric end wall curved surface; The end wall circumferential curve in the standard space is mapped into the end wall circumferential curve of the compressor through coordinate transformation. When the non-axisymmetric end wall is located on the hub surface, the coordinate mapping equation is: in, r 根 Indicates the wheel radius corresponding to the current z-axis coordinate. h 叶 Indicates leaf height, θ 压 represents the angle between the pressure side of the blade and the positive direction of the y-axis; z 前 represents the z-axis coordinate of the leading edge of the compressor blade, z 尾 Represents the z-axis coordinate of the trailing edge point of the compressor blade; is the number of cycles that flow to; The end wall circumferential curve in the standard space is mapped into the end wall circumferential curve of the compressor through coordinate transformation. When the non-axisymmetric end wall is located on the casing surface, the coordinate mapping equation is: in, r 尖 Indicates the casing radius corresponding to the current z-axis coordinate.

2. According to claim 1, a compressor coupling blade root rounding and non-axisymmetric end wall molding method is characterized by: The flow field information under the near-stall condition is extracted through the compressor corner streamline topology, secondary flow distribution cloud map and dissipation function distribution cloud map.

3. The method for coupling compressor blade root rounding and non-axisymmetric end wall molding according to claim 1, characterized in that: The method for constructing the root rounding circumferential curve of the compressor blade is: Two uniform B-spline curves are respectively selected at the corner separation position of the suction surface and the pressure surface of the blade to control the circumferential shape of the inverted circle; Set the number of control points and the order of basis functions of the B-spline curve; The equation for constructing the B-spline curve is as follows: in, d i Represents control points i The coordinates of N i,k express k Order B-spline basis function; i Indicates the control point number, k represents the order of the basis function; Basis Functions N i,k The recursive formula is used to construct the circumferential curve of the compressor blade root fillet, and the formula is as follows: in, u i is the basis function node; The basis functions of each order are obtained by iterative calculation according to the recursive formula; when the situation of 0 / 0 appears in the recursive process, the numerical ratio is defined as 0.

4. A compressor coupling blade root rounding and non-axisymmetric end wall molding method according to claim 3, characterized in that: The method for constructing the blade root rounding spanwise profile of the compressor blade is: The cubic function is used to construct the blade root fillet span profile, and the specific function equation is: in, h Indicates the fillet span height; t The value ranges from 0 to 1, reflecting the change in rounding thickness; a, b, c Three coefficients to control the spanwise profile change of blade root rounding; h 叶 Indicates leaf height; By Constraint a, b, c The three coefficients ensure smooth contact between the chamfer and the blade, and between the chamfer and the end wall, and prevent sharp edges from appearing in the corner area, which will affect the aerodynamic performance of the model. The specific constraints are: 。 5. A compressor coupling blade root rounding and non-axisymmetric end wall molding method according to claim 4, characterized in that: The distribution expression of the blade root rounding thickness of the compressor blade is: in, BS(z) and BP(z) They represent the fillet thickness of the suction side and the pressure side under the control of the B-spline curve respectively; z represents the coordinate of the z-axis.

6. A compressor coupling blade root rounding and non-axisymmetric end wall molding method according to claim 5, characterized in that: The method for establishing the end wall circumferential curve in the standard space is: In the Cartesian coordinate system, a normalized standard space is established, that is, the value ranges of the three directions X, Y, and Z are all [0,1], where X represents the blade span direction, Y represents the channel circumferential direction, and Z represents the channel axial direction; At multiple positions evenly spaced in the Z direction, the end wall circumferential curve is established using a third-order Fourier function. At the same time, the fluctuation amplitude of the end wall circumferential curve at the starting position and the end position is guaranteed to be constant at 0; the expression of the end wall circumferential curve is: in, C m and S m It represents the coefficient that controls the fluctuation of the circumferential curve of the end wall in the standard space. m represents the order of the Fourier function; L It represents the parameter that controls the maximum fluctuation amplitude of the circumferential curve of the end wall in the standard space, and its value is in the range of 0~1; x 标 , y 标 , z 标 They represent the coordinates of each point on the circumferential curve of the end wall in the standard space; ω represents the coefficient that controls the period of the Fourier curve; j Indicates the serial number of the circumferential curve of the end wall in the standard space on the Z axis.

7. A compressor coupling blade root rounding and non-axisymmetric end wall molding method according to claim 6, characterized in that: The height fluctuation of the non-axisymmetric end wall is [-2.5%, 2.5%]× h 叶 Varies within range.

8. The method for shaping a compressor coupling blade root rounding and a non-axisymmetric end wall according to claim 7, characterized in that: The compressor flow channel model is structured grid-divided by NUMECA-Autogrid5, and the structured grid is exported.

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