Method for obtaining rotor blade and stacking line of axial flow compressor

Abstract

The application discloses a rotor blade of an axial flow compressor and a method for obtaining a stacking line of the rotor blade. The method comprises the following steps: determining a circumferential position of the stacking line; the stacking line is S-shaped in the circumferential direction, and the stacking line is formed by controlling four points A, B, C and D which are sequentially preset in the height direction from the blade root to the blade tip; the coordinates of each sectional center of gravity circumferential position point conform to a specific formula; determining an axial position of the stacking line; the coordinates of each sectional center of gravity axial position point conform to a specific formula; and determining a line type of the stacking line according to the determined axial position and the circumferential position of the stacking line. The stacking line of the rotor blade is S-shaped in the circumferential direction, so that an adverse pressure gradient can be generated in the radial direction, thereby weakening the influence of the secondary flow in the blade tip area; and a specific function is set to control the circumferential and axial offset of the stacking line by constructing a simple equation, thereby improving the calculation efficiency of the optimized blade type.

Description

TECHNICAL FIELD

[0001] The application relates to a rotor blade of an axial flow compressor and a method for obtaining a stacking line of the rotor blade. BACKGROUND

[0002] With the development of science and technology, the requirements for economy and reliability of modern aeroengines are higher and higher, and the performance of components of the aeroengines encounters unprecedented challenges. The axial flow compressor is one of core components of the aeroengines, and the performance of the axial flow compressor has a decisive influence on the entire engine. However, with the continuous improvement of performance indexes of the aeroengines, the temperature and pressure ratio inside the engine gradually increase, and the loss problem of the flow system in the compressor is increasingly serious. The flow loss in the multi-stage high-pressure ratio axial flow compressor seriously affects the aerodynamic performance of the compressor, and further affects the performance of the entire engine.

[0003] The compressor loss mainly comes from blade profile loss, end wall loss and leakage loss. The flow in the end wall region of the high-load compressor is very complex, and the end wall boundary layer loss and the tip leakage loss are main components of the loss of the rotor blade of the compressor.

[0004] The compressor is a rotating component in the aeroengine that bears the largest adverse pressure gradient, and it is a big problem for the compressor design to realize efficient airflow pressurization. In the corner region composed of the hub and the suction surface of the blade root of the rotor, separation is prone to occur due to the influence of the hub boundary layer and the gas undercurrent, and aerodynamic loss is generated, which causes the efficiency of the compressor to decrease. In the tip region, there is a gap between the rotor and the outer casing, and the airflow on the pressure surface of the rotor blade will leak to the suction surface of the blade through the gap, and complex secondary flow characteristics such as leakage vortex are generated. In addition, the tangential velocity of the rotor blade is relatively high, and a shock wave is generated at the rotor tip of the front stage of the compressor. The shock wave, the leakage vortex and the outer casing boundary layer interfere with each other, so that the flow in the tip gap region is very complex, and there is a vortex structure with multiple complex characteristics. A large number of studies have shown that the stall of the compressor usually occurs in the tip and hub regions.

[0005] Therefore, how to effectively control the shock wave and the flow field in the tip region so as to weaken the secondary flow in the tip region is a problem to be solved in the field.

[0006] On the other hand, the design of the compressor usually needs multiple rounds of optimization iterations to obtain the ideal compressor aerodynamic blade profile. In order to save optimization time and avoid excessive reliance on the design experience of the designer, the compressor aerodynamic optimization method has been favored by the designers in recent years. The compressor design optimization method is a cross-disciplinary design method combining computational fluid dynamics and numerical optimization methods, and the basic idea is to take the aerodynamic performance as the target function value, use the optimization algorithm to continuously iterate to find the optimal compressor aerodynamic blade profile with the help of the three-dimensional numerical simulation tool of CFD. The parameterization selection method of the blade profile design is one of the most key technologies of the compressor aerodynamic optimization. How to use appropriate mathematical equations to describe the circumferential and radial stacking of the compressor so as to make it take into account the design characteristics of the compressor blade profile and the feasibility of the calculation method is a difficult problem in the optimization design of the stacking line of the compressor blade profile. SUMMARY

[0007] The technical problem to be solved by the present application is to overcome the defects of the existing axial flow compressor rotor blade that the air flow is lost, and to improve the efficiency of the blade profile optimization design, and to provide an axial flow compressor rotor blade and a method for obtaining the stacking line thereof.

[0008] The present application solves the above technical problems by the following technical solutions:

[0009] A method for obtaining the stacking line of the rotor blade of an axial flow compressor, characterized in that the rotor blade comprises a blade root and a blade tip, the rotor blade has a plurality of elementary blade profile sections along the height direction from the blade root to the blade tip, the gravity centers of the elementary blade profile sections are taken as the stacking points to be stacked along the height direction of the rotor blade to obtain the stacking line, and the method comprises the following steps:

[0010] S1: determining the circumferential position of the stacking line: the stacking line is in the shape of "S" in the circumferential direction, and in the circumferential direction, the stacking line is formed by controlling four points A, B, C and D preset in the height direction from the blade root to the blade tip in sequence, the A point is located at the gravity center position of the elementary blade profile section of the blade root, in a two-dimensional coordinate system composed of the X axis and the Y axis in the circumferential direction, the A point is located on the X axis; the B point is located on the right side of the A point on the X axis; the C point is located on the left side of the A point on the X axis; the D point is the gravity center position of the elementary blade profile section of the blade tip, and the D point is located between the B point and the C point on the X axis; the A point (x a , y a ), the B point (x b , y b ), the C point (x c , y c ) and the D point (x d , y dThe coordinates of the circumferential position point N of the centroid of each of the basic blade sections from the blade root to the blade tip. n y n The value is obtained through the following formula:

[0011] x n =(1-i) 3 *x a +3*i*(1-i) 2 *x b +3*i 2 *(1-i)*x c +i 3 *x d

[0012] y n =i

[0013] Where i is the dimensionless blade height at point N, and the value of i ranges from 0 to 1;

[0014] S2: Determine the axial position of the stacking line; preset point A (z) in the axial direction. a y a Point B (z) b y b ) and point D (z) d y d In a two-dimensional coordinate system composed of the Z-axis and Y-axis, point A is located on the Z-axis; point B is located to the right of point A on the Z-axis; and point D is located to the left of point A on the Z-axis. The coordinates (z...) of the circumferential position point N of the centroid of each of the basic airfoil sections from the blade root to the blade tip are... n y n The value is obtained through the following formula:

[0015] z n =(1-i) 2 *z a +2*i*(1-i)*z b +i 2 *z d

[0016] y n =i

[0017] Where i is the dimensionless blade height at point N, and the value of i ranges from 0 to 1;

[0018] S3: Determine the profile of the stacking line based on the axial and circumferential positions of the centroids of each basic blade section on the stacking line; extend the basic blades along the profile of the stacking line to construct a set of curves to obtain a three-dimensional rotor blade.

[0019] In the technical solution, the accumulation line of the rotor blade is in the form of "S" in the circumferential direction, which can generate a reverse pressure gradient in the radial direction, is conducive to the migration of low-energy fluid in the tip region to the blade, and further weakens the influence of the tip region secondary flow, improves the tip flow condition, and improves the stable working range of the compressor rotor blade. The coordinates of the center of gravity position points of each base element section conform to a single specific function, so as to control the circumferential deviation of the center of gravity position of each base element section by constructing a simple equation, and improve the calculation efficiency of the optimized blade profile. That is, compared with the method of constructing the accumulation line by trial and error in the prior art, the calculation efficiency is greatly improved; compared with the method of solving the accumulation by piecewise function, the equation is simple and easy to solve. It should be noted that the accumulation line of the rotor blade is in the form of "S" in the circumferential direction, which also includes the case that the accumulation line of the rotor blade is in the form of "S" in the circumferential direction.

[0020] In step S1, the circumferential coordinate of the D point is between the circumferential coordinates of the B point and the C point, that is, x c < x d < x b The dimensionless blade height y d is 1.

[0021] Unlike the circumferential deviation, the axial deviation controls the sweep degree of the blade profile. In the technical solution, the axial coordinate of the B point is located on the right side of the A point, and the axial coordinate of the D point is located on the left side of the A point, that is, (z4

[0022] Further, the coordinates of the axial and circumferential deviations of each base element section conform to a specific function, that is, the coordinates of the circumferential and axial position points N of the center of gravity of each base element section are obtained by a specific function, so as to control the circumferential and axial deviations of the center of gravity position by constructing a simple single equation, and improve the calculation efficiency of the optimized blade profile. That is, compared with the method of constructing the accumulation line by trial and error in the prior art, the calculation efficiency is greatly improved.

[0023] Preferably, in step S1, the angle α between the line connecting the A point and the B point and the X axis is less than 60 degrees and greater than 3 degrees; and / or,

[0024] The angle β between the line connecting the C point and the D point and the X axis is less than 45 degrees and greater than 5 degrees.

[0025] Preferably, in step S1, the circumferential coordinate x of point B is... b The circumferential coordinate x of point A is greater than that of point A. a And x b With x a The difference is taken as 0.5%-8% of the blade chord length of the section at the height of point B; the dimensionless blade height y at point B. b It ranges from 0.05 to 0.45.

[0026] Preferably, in step S1, the circumferential coordinate x of point C is... c The circumferential coordinate x of point A is less than that of point A. a And x a With x c The difference is taken as 0.5%-8% of the blade chord length of the section at the height of point C; the dimensionless blade height y at point C. c It ranges from 0.55 to 0.95.

[0027] In this technical solution, by setting the range of coordinate values ​​for points A, B, C, and D, it is beneficial to maintain a high compressor efficiency while ensuring that the rotor blades maintain a good strength level.

[0028] Preferably, in step S2, the angle θ between the line connecting point A and point B and the Z-axis is less than 70 degrees and greater than 3 degrees; and / or,

[0029] In step S2, the angle between the line connecting point B and point D and the Z-axis is... The temperature is between 40 degrees and less than 80 degrees.

[0030] Preferably, in step S2, the axial coordinate z of point B is... b The axial coordinate z of point A is greater than that of point A. a , and z b With z a The difference is taken as 0.5%-8% of the blade chord length of the section at the height of point B; the dimensionless blade height y at point B. b It ranges from 0.05 to 0.45.

[0031] Preferably, in step S2, the axial coordinate z of point D is... d The axial coordinate z of point A is less than a , and z a With z d The difference is taken as 0.5%-8% of the blade chord length of the cross section at the height of the blade tip.

[0032] In this technical solution, by setting the range of coordinate values ​​for points A, B, and D, it is beneficial to maintain a high compressor efficiency while ensuring that the rotor blades maintain a good strength level.

[0033] Preferably, after step S3, further comprising:

[0034] S4: repeating steps S1 to S3 multiple times to obtain multiple different rotor blades, obtaining multiple different compressor efficiencies corresponding to the multiple different rotor blades, and determining the optimal circumferential stacking offset and axial stacking offset to be finally used according to the principle of the highest compressor efficiency.

[0035] In the technical solution, in step S4, the dimensionless height and circumferential coordinate of multiple different A, B, C and D control points are substituted into step S1, and the dimensionless height and axial coordinate of multiple different A, B and D points are substituted into step S2, steps S1 to S3 are repeated multiple times to obtain multiple different rotor blades, that is, multiple different rotor blades are obtained through an iterative method.

[0036] The compressor efficiency of the multiple different rotor blades is calculated, the rotor blade corresponding to the highest compressor efficiency is selected as the final rotor blade to obtain a rotor blade with optimal compressor efficiency, that is, the optimal circumferential coordinate and dimensionless height of the control points A, B, C and D, and the axial coordinate and dimensionless height of the control points A, B and D are obtained; and the rotor blade with optimal circumferential stacking and axial stacking obtained through the control points.

[0037] A rotor blade of an axial flow compressor, characterized in that the rotor blade is obtained by the method for obtaining the stacking line of the rotor blade of the axial flow compressor.

[0038] The positive progress effect of the present application is that:

[0039] The present application sets the stacking line of the rotor blade to be S-shaped in the circumferential direction, which can generate an adverse pressure gradient in the radial direction, is conducive to the migration of low-energy fluid in the tip region to the middle of the blade, and further weakens the influence of the tip region secondary flow, improves the tip flow condition, and improves the stable working range of the compressor rotor blade. The four control point coordinate variables and the relatively simple fourth-order equation are used to parameterize the description of the circumferential offset of the compressor "S". The stacking line of the rotor blade is set to be a composite sweep type in the axial direction, specifically a backward sweep at the blade root to reduce the risk of axial rubbing during surge, and a forward sweep at the blade tip to increase the efficiency and stable working range of the compressor. The three control point coordinate variables and the relatively simple equation are used to parameterize the description of the axial direction of the composite sweep type of the compressor. Further, the optimal circumferential offset and axial offset distribution are determined according to the principle of minimum loss or optimal efficiency.

[0040] The parameterized equation of the circumferential and axial offset is simple, the generated curve is smooth and continuous, and the calculation efficiency of optimizing the blade profile is improved. That is, compared with the way of constructing the stacking line by trial and error in the prior art, the calculation efficiency is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 A flowchart of a method for obtaining a stacking line of a rotor blade of an axial flow compressor according to an embodiment of the present application.

[0042] Figure 2 A schematic diagram of a circumferential offset of a stacking line of a rotor blade of an axial flow compressor according to an embodiment of the present application.

[0043] Figure 3 A schematic diagram of an axial offset of a stacking line of a rotor blade of an axial flow compressor according to an embodiment of the present application.

[0044] Figure 4 A flowchart of a method for obtaining a stacking line of a rotor blade of an axial flow compressor according to an embodiment of the present application.

[0045] Figure 5 A schematic diagram of a meridian plane structure of a final blade profile of a rotor blade of an axial flow compressor according to an embodiment of the present application.

[0046] Figure 6 A schematic diagram of a meridian plane structure of an original blade profile of a rotor blade of an axial flow compressor according to an embodiment of the present application. DETAILED DESCRIPTION

[0047] The embodiment provides a method for obtaining a stacking line of a rotor blade of an axial flow compressor.

[0048] The rotor blade includes a blade root and a blade tip, and has a plurality of elementary blade profile sections along a height direction from the blade root to the blade tip. Centers of gravity of the elementary blade profile sections are taken as stacking points to be stacked along the height direction of the rotor blade to obtain the stacking line.

[0049] As Figure 1 shown, the method for obtaining the stacking line of the rotor blade of the axial flow compressor according to the embodiment includes the following steps:

[0050] S1: determine the circumferential position of the accumulation line: the accumulation line is "S" type in the circumferential direction, and the accumulation line is formed by four points A, B, C and D preset in the height direction from the root to the tip in sequence, the A point is located at the barycentric position of the root element airfoil section, in the two-dimensional coordinate system composed of the circumferential X axis and Y axis, the A point is located on the X axis; the B point is located on the right side of the A point on the X axis; the C point is located on the left side of the A point on the X axis; the D point is the barycentric position of the element airfoil section at the tip, and the D point is located between the B point and the C point on the X axis; the coordinates of the A point (x a , y a ), the B point (x b , y b ), the C point (x c , y c ) and the D point (x d , y d ) are preset, and the coordinates (x n , y n ) of the barycentric position point N of each element airfoil section from the root to the tip are obtained by the following formula:

[0051] x n =(1-i) 3 *x a +3*i*(1-i) 2 *x b +3*i 2 *(1-i)*x c +i 3 *x d

[0052] y n =i

[0053] Wherein, i is the dimensionless blade height of the N point, and the value range of i is 0-1;

[0054] S2: determine the axial position of the accumulation line; preset the A point (z a , y a ), the B point (z b , y b ) and the D point (z d , y d ) in the axial direction, in the two-dimensional coordinate system composed of the axial Z axis and Y axis, the A point is located on the Z axis; the B point is located on the right side of the A point on the Z axis, and the D point is located on the left side of the A point on the Z axis, the coordinates (z n , y n ) of the barycentric position point N of each element airfoil section from the root to the tip are obtained by the following formula:

[0055] z n = (1-i) 2 *z a +2*i*(1-i)*z b +i 2 *z d

[0056] y n =i

[0057] Where i is the dimensionless blade height at point N, and the value of i ranges from 0 to 1;

[0058] S3: Determine the profile of the stacking line based on the axial and circumferential positions of the centroids of each basic blade section on the stacking line; extend the basic blades along the profile of the stacking line to construct a set of curves to obtain a three-dimensional rotor blade.

[0059] In step S1, the circumferential position of the stacking line is determined as follows: Figure 2 As shown, that is, by presetting point A (x) a y a Point B (x) b y b Point C (x) c y c ) and point D (x d y d The coordinates of points A, B, C, and D are obtained, namely the dimensionless height (Y-axis coordinate) and circumferential coordinate (X-axis coordinate). Then, the height and circumferential stacking offset of the circumferential position point N of the centroid of each basic blade section from the blade root to the blade tip are solved by a specific formula, thus obtaining the coordinates of N in the two-dimensional coordinate system composed of the circumferential X-axis and Y-axis.

[0060] In this way, by setting the stacking line of the rotor blades to be "S"-shaped in the circumferential direction, a reverse pressure gradient can be generated in the radial direction. This facilitates the migration of low-energy fluid from the blade tip region to the middle of the blade, thereby reducing the influence of secondary flow in the blade tip region, improving the flow conditions at the blade tip, and extending the stable operating range of the compressor rotor blades. The coordinates of the centroid position of each basic airfoil section conform to a single specific function, allowing for the control of the circumferential offset of the centroid position of each basic airfoil section through the construction of simple equations, thus improving the computational efficiency of airfoil optimization. In other words, compared to the existing method of constructing the stacking line through trial and error, this significantly improves computational efficiency; compared to the piecewise function method of solving the stacking, it has the advantages of simple equations and convenient solutions. It should be noted that the "S"-shaped stacking line of the rotor blades in the circumferential direction also includes the case where the stacking line of the rotor blades is approximately "S"-shaped in the circumferential direction.

[0061] In step S1, the circumferential coordinate of the D point is between the circumferential coordinates of the B point and the C point, that is, x c d b The dimensionless blade height y d of the D point is 1.

[0062] The axial position of the stacking line is determined in step S2 as shown in Figure 3 That is, the coordinates of the A point (z a , y a ), the B point (z b , y b ), and the D point (z d , y d ), that is, the dimensionless height (Y-axis coordinate) and the axial coordinate (Z-axis coordinate) of the A point, the B point, and the D point, are preset, and then the height and the axial offset of each of the elemental blade profile sections from the blade root to the blade tip are solved by a specific formula, that is, the coordinates of N in the two-dimensional coordinate system composed of the Y-axis and the Z-axis are obtained.

[0063] It should be noted that in Figure 3 the horizontal axis of the axial offset diagram is the axial offset, and the vertical axis is the dimensionless height, wherein the dimensionless height of the B point is consistent with Figure 2 the dimensionless height of the B point in the circumferential offset diagram, that is, they are the same point. Similarly, the dimensionless heights of the A point and the D point in Figure 2 and Figure 3 are also consistent.

[0064] Unlike the circumferential offset, the axial offset controls the sweep degree of the blade profile. In the present technical solution, the axial coordinate of the B point is located to the right of the A point, and the axial coordinate of the D point is located to the left of the A point, that is, (z4<z1<z2), that is, a backward sweep is formed at the position of the B point blade height, and a forward sweep is formed at the B point and the D point. The forward sweep at the blade tip position of the D point helps the rotor to maintain a relatively high stable working range, and the backward sweep at the blade root position of the A point helps to improve the stability of the structure, because the blade will move forward during surging. Setting a backward sweep can reduce the risk of collision and maintain a high blade root efficiency.

[0065] Further, the coordinates of the axial and circumferential offsets of each elemental blade profile section conform to a specific function, that is, the coordinates of the circumferential and axial position points N of the center of gravity of each of the elemental blade profile sections are obtained by a specific function, so as to control the circumferential offset of the center of gravity position by a single equation which is simple to construct, thereby improving the calculation efficiency of the optimized blade profile. That is, compared with the way of constructing the stacking line by trial and error in the prior art, the calculation efficiency is greatly improved.

[0066] ​​For a better option, please refer to [the original text]. Figure 2 In step S1, the angle α between the line connecting points A and B and the X-axis is less than 60 degrees and greater than 3 degrees. The angle β between the line connecting points C and D and the X-axis is less than 45 degrees and greater than 5 degrees. By setting the range of values ​​for angles α and β, it is beneficial to maintain a high compressor efficiency while ensuring that the rotor blades maintain a good strength level.

[0067] In step S1, the circumferential coordinate x of point B b The circumferential coordinate x of point A is greater than that of point A. a And x b With x a The difference (x) b -x a The blade chord length at the height of point B is taken as 0.5%-8% of the cross-section at which point B is located; the dimensionless blade height y at point B is... b It ranges from 0.05 to 0.45.

[0068] In step S1, the circumferential coordinate x of point C c The circumferential coordinate x of point A is less than that of point A. a And x a With x c The difference (x) a -x c The blade chord length at the height of point C is taken as 0.5%-8% of the cross-section at which point C is located; the dimensionless blade height y at point C is... c It ranges from 0.55 to 0.95.

[0069] In this way, by setting the range of coordinate values ​​for points A, B, C, and D, it is beneficial to maintain a high compressor efficiency while ensuring that the rotor blades maintain a good strength level.

[0070] For a better option, please refer to [the original text]. Figure 3 In step S2, the angle θ between the line connecting points A and B and the Z-axis is less than 70 degrees and greater than 3 degrees. The angle θ between the line connecting points B and D and the Z-axis... The angle is between 40 degrees and less than 80 degrees. This is determined by setting the included angle θ and the included angle... The range of values ​​is beneficial for maintaining high compressor efficiency while ensuring that the rotor blades maintain a good strength level.

[0071] In step S2, the axial coordinate z of point B b The axial coordinate z of point A is greater than that of point A. a , and z b With z a The difference (z) b -z aThe blade chord length at the height of point B is taken as 0.5%-8% of the cross-section at which point B is located; the dimensionless blade height y at point B is... b It ranges from 0.05 to 0.45.

[0072] In step S2, the axial coordinate of point D is to the left of the axial coordinate of point A, that is, the axial coordinate z of point D is... d The axial coordinate z of point A is less than a , i.e. z d <z a , and z a With z d The difference (z) a -z d The value is taken as 0.5%-8% of the chord length of the blade at the height of the blade tip.

[0073] In this way, by setting the range of coordinate values ​​for points A, B, and D, it is beneficial to maintain a high compressor efficiency while ensuring that the rotor blades maintain a good strength level.

[0074] Preferably, after step S3, the method further includes:

[0075] S4: Repeat steps S1 to S3 multiple times to obtain multiple different rotor blades and the compressor efficiencies corresponding to the multiple different rotor blades. Based on the principle of maximizing compressor efficiency, determine the optimal circumferential stacking offset and axial stacking offset to be used in the end.

[0076] Thus, in step S4, the dimensionless height and circumferential coordinates of multiple different control points A, B, C, and D are substituted into step S1, and the dimensionless height and axial coordinates of multiple different control points A, B, and D are substituted into step S2. Steps S1 to S3 are repeated multiple times to obtain multiple different rotor blades. That is, multiple different rotor blades are obtained through an iterative method, and these rotor blades correspond to the axial and circumferential coordinates of different control points.

[0077] Compressor efficiency is calculated for multiple different rotor blades, and the rotor blade corresponding to the highest compressor efficiency is selected as the final rotor blade to obtain the rotor blade with optimal compressor efficiency. This yields the optimal circumferential coordinates and dimensionless height of control points A, B, C, and D, as well as the axial coordinates and dimensionless height of control points A, B, and D; and the optimal circumferential and axial stacked rotor blades obtained through calculations using these control points.

[0078] That is, aerodynamic performance is used as the objective function value, and the compressor efficiency is calculated with the help of mesh generation and CFD three-dimensional numerical simulation tools. The optimal compressor aerodynamic blade profile is found by iterative optimization algorithm.

[0079] It should be noted that in other embodiments, the axial position of the stacking line can be determined first, and then the circumferential position of the stacking line can be determined, or the steps S1 and S2 can be performed simultaneously.

[0080] As shown in Figure 4 , Figure 4 is a flowchart of the method comprising all the above steps.

[0081] As shown in Figure 5 , the embodiment also provides a rotor blade 10 of an axial flow compressor, which is obtained by the above method for obtaining the stacking line of the rotor blade of the axial flow compressor.

[0082] It should be noted that Figure 5 the final blade shape of the rotor blade 10 is obtained on the basis of the original blade shape of the rotor blade 10' in Figure 6 by the above method for obtaining the stacking line of the rotor blade of the axial flow compressor. As can be seen from Figure 6 , the stacking line 20' of the original blade shape of the rotor blade 10' is a straight line; and the stacking line 20 of the finally obtained rotor blade 10 of the embodiment is a composite sweep type in the axial direction, that is, it is backward swept near the blade root position and forward swept near the blade tip, as shown in Figure 5 .

[0083] The embodiment sets the stacking line of the rotor blade to be S-shaped in the circumferential direction, so that an adverse pressure gradient can be generated in the radial direction, which is beneficial to the migration of low-energy fluid in the tip region to the middle of the blade, thereby weakening the influence of the secondary flow in the tip region, improving the flow condition in the tip region, and improving the stable working range of the compressor rotor blade. The circumferential offset of the compressor "S" type is parameterized by four coordinate variables of control points and a relatively simple fourth-order equation. The stacking line of the rotor blade is set to be a composite sweep type in the axial direction, specifically, it is backward swept at the blade root to reduce the risk of axial rubbing in surge; and it is forward swept at the blade tip to increase the efficiency and stable working range of the compressor. The axial direction of the composite sweep type of the compressor is parameterized by three coordinate variables of control points and a relatively simple equation. Further, the optimal circumferential offset and axial offset distribution are determined according to the principle of minimum loss or maximum efficiency.

[0084] The parameterization equation of the circumferential and axial offset is simple, and the generated curve is smooth and continuous, which is beneficial to improving the calculation efficiency of the optimized blade shape. That is, compared with the method of constructing the stacking line by trial and error in the prior art, the calculation efficiency is greatly improved.

[0085] Although the specific embodiments of the present application have been described above, it is understood by those skilled in the art that the present application is only illustrated by way of example, and the scope of protection of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to the embodiments without departing from the principles and essence of the present application, and such changes and modifications fall within the scope of protection of the present application.

Claims

1. A method for obtaining the stacking lines of rotor blades of an axial compressor, characterized in that, The rotor blade includes a blade root and a blade tip. The rotor blade has a plurality of basic airfoil sections along the height direction from the blade root to the blade tip. The centroids of each basic airfoil section are used as accumulation points and superimposed along the height direction of the rotor blade to obtain an accumulation line. The method for obtaining the accumulation line includes the following steps: S1: Determine the circumferential position of the accumulation line: The accumulation line is "S"-shaped in the circumferential direction. In the circumferential direction, the accumulation line is formed by four points A, B, C, and D, which are preset sequentially from the leaf root to the leaf tip in the height direction. Point A is located at the centroid of the basic blade section at the leaf root. In the two-dimensional coordinate system composed of the X-axis and Y-axis in the circumferential direction, point A is located on the X-axis; point B is located to the right of point A on the X-axis; point C is located to the left of point A on the X-axis; point D is located at the centroid of the basic blade section at the leaf tip, and point D is located between points B and C on the X-axis; the preset position of point A (x a y a Point B (x) b y b Point C (x) c y c ) and point D (x d y d The coordinates of the circumferential position point N of the centroid of each of the basic blade sections from the blade root to the blade tip. n y n The value is obtained through the following formula: x n =(1-i) 3 *x a +3*i*(1-i) 2 *x b +3*i 2 *(1-i)*x c +i 3 *x d y n =i Where i is the dimensionless blade height at point N, and the value of i ranges from 0 to 1; S2: Determine the axial position of the stacking line; preset point A (z) in the axial direction. a y a Point B (z) b y b ) and point D (z) d y d In a two-dimensional coordinate system composed of the Z-axis and Y-axis, point A is located on the Z-axis; point B is located to the right of point A on the Z-axis; and point D is located to the left of point A on the Z-axis. The coordinates (z...) of the circumferential position point N of the centroid of each of the basic airfoil sections from the blade root to the blade tip are... n y n The value is obtained through the following formula: z n =(1-i) 2 *z a +2*i*(1-i)*z b +i 2 *z d y n =i Where i is the dimensionless blade height at point N, and the value of i ranges from 0 to 1; S3: Determine the profile of the stacking line based on the axial and circumferential positions of the centroids of each basic blade section on the stacking line; extend the basic blades along the profile of the stacking line to construct a set of curves to obtain a three-dimensional rotor blade.

2. The method for obtaining the stacking line of the rotor blades of an axial compressor as described in claim 1, characterized in that, In step S1, the angle α between the line connecting points A and B and the X-axis is less than 60 degrees and greater than 3 degrees; and / or, In step S1, the angle β between the line connecting point C and point D and the X-axis is less than 45 degrees and greater than 5 degrees.

3. The method for obtaining the stacking line of the rotor blades of an axial compressor as described in claim 1, characterized in that, In step S1, the circumferential coordinate x of point B b The circumferential coordinate x of point A is greater than that of point A. a And x b With x a The difference is taken as 0.5%-8% of the blade chord length of the section at the height of point B; the dimensionless blade height y at point B. b It ranges from 0.05 to 0.

45.

4. The method for obtaining the stacking line of the rotor blades of an axial compressor as described in claim 1, characterized in that, In step S1, the circumferential coordinate x of point C c The circumferential coordinate x of point A is less than that of point A. a And x a With x c The difference is taken as 0.5%-8% of the blade chord length of the section at the height of point C; the dimensionless blade height y at point C. c It ranges from 0.55 to 0.

95.

5. The method for obtaining the stacking line of the rotor blades of an axial compressor as described in claim 1, characterized in that, In step S2, the angle θ between the line connecting points A and B and the Z-axis is less than 70 degrees and greater than 3 degrees; and / or, In step S2, the angle between the line connecting point B and point D and the Z-axis is... The temperature is between 40 degrees and less than 80 degrees.

6. The method for obtaining the stacking line of the rotor blades of an axial compressor as described in claim 1, characterized in that, In step S2, the axial coordinate z of point B b The axial coordinate z of point A is greater than that of point A. a , and z b With z a The difference is taken as 0.5%-8% of the blade chord length of the section at the height of point B; the dimensionless blade height y at point B. b It ranges from 0.05 to 0.

45.

7. The method for obtaining the stacking line of the rotor blades of an axial compressor as described in claim 1, characterized in that, In step S2, the axial coordinate z of point D d The axial coordinate z of point A is less than a , and z a With z d The difference is taken as 0.5%-8% of the blade chord length of the cross section at the height of the blade tip.

8. The method for obtaining the stacking line of the rotor blades of an axial compressor as described in any one of claims 1-7, characterized in that, Following step S3, the following is also included: S4: Repeat steps S1 to S3 multiple times to obtain multiple different rotor blades and the compressor efficiencies corresponding to the multiple different rotor blades. Based on the principle of maximizing compressor efficiency, determine the optimal circumferential stacking offset and axial stacking offset to be used in the end.

9. A rotor blade for an axial flow compressor, characterized in that, The rotor blades are obtained by the method for obtaining the stacking line of the rotor blades of the axial compressor as described in any one of claims 1-8.

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