A method, system, device, and medium for calculating the blade installation angle and chord length.

Abstract

This invention belongs to the field of impeller and aerodynamics, involving airfoil design and fluid machinery technology. It provides a method, system, device, and medium for calculating the airfoil installation angle and chord length. The method includes: generating a discrete point sequence by densely sampling the airfoil profile; determining the tangent and normal directions of each point; using the airfoil on the blade head side between the minimum and maximum axial coordinate points as the test range; searching for chord starting point pairs within the test range that meet certain conditions, i.e., a pair of adjacent test points each have corresponding points with consistent tangent directions on opposite sides of the region, and the deviation of the line connecting the two test points and their corresponding points relative to the normal has opposite signs or at least one is zero; determining whether the chord direction meets a preset accuracy threshold and achieving convergence through local densification and re-search; finally, outputting the installation angle based on the effective chord direction and the axial angle, and simultaneously calculating the chord length based on the chord direction. This method eliminates the need for curvature calculation, is applicable to airfoils with arbitrary leading / tailing edge shapes, and offers high accuracy, good stability, and strong adaptability.

Description

Technical Field

[0001] This invention belongs to the field of turbomachinery design in fluid machinery, and relates to airfoil geometric parameter calculation technology, specifically to a method, system, equipment and medium for calculating airfoil installation angle and chord length. Background Technology

[0002] In turbomachinery such as aero engines, the airfoil installation angle is one of the key parameters characterizing the airfoil's geometry, and it is widely used in airfoil design, manufacturing, surveying, and assembly. Currently, the calculation of the airfoil installation angle and chord length is usually based on the assumption that the leading and trailing edges of the airfoil are standard circular arcs. However, in practical engineering applications, the leading and trailing edges of airfoils are often not ideal circular arcs, and with the development of advanced aerodynamic design, more and more airfoils are adopting non-circular arc or even complex curvature transition structures. This circular arc assumption deviates significantly from the actual airfoil geometry, resulting in insufficient accuracy of traditional calculation methods, making it difficult to meet the needs of high-precision airfoil engineering applications.

[0003] Therefore, there is an urgent need for a high-precision installation angle calculation method that does not rely on the leading / tailing edge arc assumption and is applicable to any airfoil profile. Summary of the Invention

[0004] To address the problem of insufficient accuracy in calculating airfoil mounting angles in existing technologies due to reliance on the leading / tailing edge arc assumption, this invention discloses a method for calculating airfoil mounting angles and chord lengths that does not rely on this assumption and is applicable to any airfoil profile, such as compressor airfoils or turbine airfoils. The method includes the following steps:

[0005] S1. The input leaf profile is sampled in a high-resolution manner to generate a discrete point sequence. The tangent direction and normal direction at each sampling point are determined by the discrete point sequence. S2. Obtain the axial coordinates of each sampling point on the blade profile based on the overall coordinate system of the turbomachinery, and determine the blade profile on the blade head side between the minimum point of the axial coordinate and the maximum point of the axial coordinate as the test range. S3. Search within the test range for pairs of chord starting points that satisfy the chord geometry conditions. The chord geometry conditions are: there exists a pair of adjacent test points, and for each of the adjacent test points, a corresponding point with the same tangent direction can be found within the test range and at a position on the other side of the axial coordinate of that point; and the deviations between the direction of the line connecting each of the adjacent test points and its corresponding point and the normal direction satisfy the condition that the signs are opposite or at least one of the deviations is zero. S4. Determine whether the chord starting point satisfies the preset chord accuracy threshold for the determined chord direction; S5. If satisfied, calculate the blade installation angle based on the chord direction; S6. If not satisfied, the interval between the chord starting point pairs is locally encrypted, and a new chord starting point pair that satisfies the chord geometric conditions is searched again in the locally encrypted interval. The accuracy judgment and local encryption operation are repeated for the new chord starting point pairs until a chord that satisfies the chord accuracy threshold is obtained, and the blade installation angle is calculated based on the chord. S7. Traverse the leaf shape contour, sequentially search for two chord length positioning points on the leaf shape contour whose tangents are perpendicular to the chord direction, extract the intersection points of the tangents of the two chord length positioning points and the chord direction respectively, and calculate the distance between the two intersection points to obtain the chord length.

[0006] This invention also provides a calculation system for the blade installation angle and chord length, including an encryption preprocessing unit, a chord starting point search unit, a precision control unit, an installation angle calculation unit, and a chord length calculation unit.

[0007] Specifically, the encryption preprocessing unit is used to perform encryption sampling on the input blade profile to generate a discrete point sequence, and to determine the tangent direction and normal direction at each sampling point through the discrete point sequence; the axial coordinates of each sampling point on the blade profile are obtained according to the overall coordinate system of the turbomachinery, and the blade profile on the blade head side between the minimum point of axial coordinates and the maximum point of axial coordinates is determined as the test range; The chord start point search unit is used to search for pairs of chord start points that satisfy the chord geometric conditions within the test range. The chord geometric conditions are: there exists a pair of adjacent test points, and for each of the adjacent test points, a corresponding point with the same tangent direction can be found within the test range and at a position on the other side of the axial coordinate of that point; and the deviations between the direction of the line connecting each of the adjacent test points and its corresponding point and the normal direction satisfy the condition that the signs are opposite or at least one of the deviations is zero. The precision control unit is used to determine whether the chord direction determined by the chord direction starting point pair meets the preset chord direction precision threshold; if it meets the threshold, the airfoil installation angle is calculated based on the chord direction; if it does not meet the threshold, the interval between the chord direction starting point pairs is locally encrypted, and a new chord direction starting point pair that meets the chord direction geometric conditions is searched again in the locally encrypted interval. The precision judgment and local encryption operation are repeated for the new chord direction starting point pair until a chord direction that meets the chord direction precision threshold is obtained. The installation angle calculation unit is used to calculate the blade installation angle based on the chord direction, wherein the chord direction is the direction of the line connecting the point with the smaller absolute value of the centering deviation of the starting point of the chord direction and its corresponding point, and the blade installation angle is the angle between the chord direction and the axial direction in the overall coordinate system of the turbomachinery. The chord length calculation unit is used to traverse the leaf profile, sequentially search for two chord length positioning points on the leaf profile whose tangents are perpendicular to the chord direction, extract the intersection points of the tangents of the two chord length positioning points and the chord direction respectively, and calculate the distance between the two intersection points to obtain the chord length.

[0008] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-mentioned methods for calculating arbitrary blade mounting angles and chord lengths, thereby solving the problem of insufficient accuracy in calculating blade mounting angles due to reliance on the leading / tailing edge arc assumption in the prior art.

[0009] This invention also provides a computer-readable storage medium storing a computer program that performs the above-described methods for calculating any blade mounting angle and chord length, in order to solve the problem of insufficient accuracy in calculating the blade mounting angle due to reliance on the leading / tailing edge arc assumption in the prior art.

[0010] This invention proposes a chord direction identification mechanism based on the geometric characteristics of the blade profile: the chord direction corresponding to the true installation angle should satisfy the following condition—starting from a point in the front segment, a corresponding point with the same tangent direction can be found in the rear segment, and the deviation sign between the line connecting the two points and their respective corresponding points and the normal direction of the two points is opposite or at least zero. This criterion reflects the local geometric symmetry on both sides of the chord direction, without relying on the assumption that the leading or trailing edge is of a specific shape (such as an arc). By traversing candidate point pairs within the test range, and combining the deviation sign criterion with adaptive local encryption, high-precision chord direction can be efficiently and stably converged.

[0011] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least: 1. This invention only requires the first derivative of the leaf-shaped curve to be continuous (i.e., the tangent direction exists and is continuous), without involving the calculation of the second derivative or curvature, thus avoiding noise amplification and numerical instability. The algorithm has a simple structure, good stability, fast convergence speed, and high calculation accuracy. 2. The method of the present invention is applicable to both traditional airfoils with standard circular arcs at the leading and trailing edges, and modern high-performance airfoils with ellipses, splines, or arbitrary free curvatures at the leading / tailing edges, breaking through the limitations of the traditional chord definition on geometric form; 3. This invention has a clear geometric meaning, is logically intuitive and easy to understand, is easy to program and implement, can be seamlessly integrated into CAD / CAM / CMM systems, supports automated high-precision blade installation angle calculation, and significantly improves the consistency and reliability of turbomachinery design and manufacturing. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a flowchart illustrating the calculation method for the blade installation angle and chord length disclosed in an embodiment of the present invention; Figure 2 This is the process of reverse searching for test points within the test range disclosed in the embodiments of the present invention; Figure 3 This is the calculation process for the installation angle of a turbine blade in an embodiment of the present invention; Figure 4 This is a schematic diagram showing the positions of test point A1 and its corresponding point B1 on the leaf profile in an embodiment of the present invention; Figure 5 This is a schematic diagram showing the positions of test point A2 and its corresponding point B2 on the leaf profile in an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the relationship between the tangent line of the test point on the leaf profile and the tangent lines of two adjacent search points in an embodiment of the present invention. Figure 7 This is a partially enlarged schematic diagram of two adjacent search points and their tangents on the leaf profile in an embodiment of the present invention; Figure 8 This is a schematic diagram of the leaf chord length in an embodiment of the present invention; Figure 9 This is an architecture diagram of the blade installation angle and chord length calculation system disclosed in an embodiment of the present invention; Among them, 1. Minimum point of axial coordinate; 2. Maximum point of axial coordinate; 3. Tangent of test point A1; 4. Tangent of test point A2; 5. Line connecting A1 and B1; 6. Normal line of test point A1; 7. Line connecting A2 and B2; 8. Normal line of test point A2; 9. Tangent of a certain test point; 10. The j-th searched point; 11. The (j+1)-th searched point; 12. Tangent of searched point j; 13. Angle between the tangent of searched point j and the tangent of its corresponding test point; 14. Tangent of searched point j+1; 15. Angle between the tangent of searched point j+1 and the tangent of its corresponding test point; 16. Chord direction; 901. Encryption preprocessing unit; 902. Chord direction starting point search unit; 903. Precision control unit; 904. Installation angle calculation unit; 905. Chord length calculation unit. Detailed Implementation

[0014] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0015] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features of the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0016] like Figure 1 As shown, this invention discloses a method for calculating the airfoil installation angle and chord length. This method does not rely on this assumption and is applicable to any airfoil profile, such as compressor airfoils or turbine airfoils. Specifically, the method includes the following steps: S1. The input leaf profile is sampled in a high-resolution manner to generate a discrete point sequence. The tangent direction and normal direction at each sampling point are determined by the discrete point sequence. S2. Obtain the axial coordinates of each sampling point on the blade profile based on the overall coordinate system of the turbomachinery, and determine the blade profile on the blade head side between the minimum point of the axial coordinate and the maximum point of the axial coordinate as the test range. S3. Search within the test range for pairs of chord starting points that satisfy the chord geometry conditions. The chord geometry conditions are: there exists a pair of adjacent test points, and for each of the adjacent test points, a corresponding point with the same tangent direction can be found within the test range and at a position on the other side of the axial coordinate of that point; and the deviations between the direction of the line connecting each of the adjacent test points and its corresponding point and the normal direction satisfy the condition that the signs are opposite or at least one of the deviations is zero. S4. Determine whether the chord starting point satisfies the preset chord accuracy threshold for the determined chord direction; S5. If satisfied, calculate the blade installation angle based on the chord direction; S6. If not satisfied, the interval between the chord starting point pairs is locally encrypted, and a new chord starting point pair that satisfies the chord geometric conditions is searched again in the locally encrypted interval. The accuracy judgment and local encryption operation are repeated for the new chord starting point pairs until a chord that satisfies the chord accuracy threshold is obtained, and the blade installation angle is calculated based on the chord. S7. Traverse the leaf shape contour, sequentially search for two chord length positioning points on the leaf shape contour whose tangents are perpendicular to the chord direction, extract the intersection points of the tangents of the two chord length positioning points and the chord direction respectively, and calculate the distance between the two intersection points to obtain the chord length.

[0017] In an optional embodiment, in step S3, the deviation is the angle between the direction of the line connecting the test point and its corresponding point and the normal direction of the test point, minus 90°. The chordal geometry condition is determined by judging whether the product of the two deviation values ​​is less than or equal to zero.

[0018] In an optional embodiment, step S3, searching for chord start point pairs, includes any of the following methods: Method 1: Traverse adjacent test point pairs sequentially from the front end to the back end of the test range, and for each test point in the adjacent test point pair, search for the corresponding point with the same tangent direction in the reverse direction in the latter half of the test range. Method 2: Traverse adjacent test point pairs sequentially from the end to the front of the test range, and for each test point in the adjacent test point pair, search for the corresponding point with the same tangent direction in the reverse direction in the first half of the test range.

[0019] More specifically, such as Figure 2 As shown, for each test point, the corresponding point with the same tangent direction is searched in reverse, including the following steps: S31. Traverse adjacent search point pairs in the reverse direction in the first or second half of the test range; S32. If the tangent slope of the test point is between the tangent slopes of the two points in the current adjacent search point pair, then the interval between the adjacent search point pairs is taken as the candidate corresponding interval. S33. If the accuracy of the candidate corresponding interval does not meet the preset corresponding point positioning accuracy threshold, then local encryption is performed in the candidate corresponding interval, and reverse search is continued in the encrypted interval until a corresponding point that meets the corresponding point positioning accuracy threshold is obtained, wherein the corresponding point positioning accuracy threshold f < chordal accuracy threshold e.

[0020] In an optional embodiment, in steps S5 and S6, the absolute values ​​of the deviations between the lines connecting each point in the pair of chord starting points or the new pair of chord starting points and their corresponding points are compared, the line direction with the smaller absolute value is selected as the chord direction, and the angle between the chord direction and the axial direction in the overall coordinate system of the turbomachinery is calculated as the blade installation angle.

[0021] This invention proposes a chord direction identification mechanism based on the geometric characteristics of the blade profile: the chord direction corresponding to the true installation angle should satisfy the following condition—starting from a point in the front segment, a corresponding point with the same tangent direction can be found in the rear segment, and the deviation sign between the line connecting the two points and their respective corresponding points and the normal direction of the two points is opposite or at least zero. This criterion reflects the local geometric symmetry on both sides of the chord direction, without relying on the assumption that the leading or trailing edge is of a specific shape (such as an arc). By traversing candidate point pairs within the test range, and combining the deviation sign criterion with adaptive local encryption, high-precision chord direction can be efficiently and stably converged.

[0022] This invention is combined with the appendix Figures 3 to 8 As shown, the above method is explained in detail using a two-dimensional airfoil section at 50% blade height as an example of a turbine blade. The airfoil has an elliptical leading edge and a wedge-shaped trailing edge, which does not satisfy the traditional circular arc assumption. The input data is a NURBS parametric curve, which already includes analytical derivative information, allowing extraction of the tangent direction at any point. The calculation process for the installation angle of this airfoil is as follows: Step 1: The input leaf profile is sampled in a high-density manner to generate a high-density discrete point sequence with a spacing of no more than 0.1 mm. Since the original data is a parametric curve, the tangent direction at each sampling point is directly extracted from the curve's analytical expression, and the normal direction is obtained from the orthogonality of the tangent direction.

[0023] Step 2: Based on the global coordinate system of the turbomachinery (X-axis for axial direction, Y-axis for circumferential direction), obtain the axial coordinates (i.e., X-coordinates) of each sampling point in the discrete point sequence. Define the continuous airfoil section between the minimum axial coordinate point 1 (near the leading edge) and the maximum axial coordinate point 2 (near the trailing edge) as the test range as the search curve, excluding non-working areas such as the root transition section.

[0024] Step 3: Taking the sequential traversal from the beginning to the end of the search curve as an example, the reverse search process is introduced: Step 31: Search sequentially along the curve from the leading edge to the trailing edge, starting from the first point, until the search point [i, i+1] is determined as the starting point range of the chord. The specific operation is as follows: S301. Let the i-th point of the search curve be test point A1, and let the (i+1)-th point of the search curve be test point A2.

[0025] S302. Starting from the end of the search curve, search in reverse order to calculate the test point B1 whose tangent direction on the search curve is the same as the tangent direction of test point A1 3, and calculate the test point B2 whose tangent direction on the search curve is the same as the tangent direction of test point A2 4.

[0026] If there is no test point B1 (or B2) on the search curve whose tangent direction is the same as that of test point A1 (or A2), it means that the search point [i, i+1] is not the range of the chord starting point. It is necessary to sequentially determine whether the range of the next search point on the search curve is the range of the chord starting point.

[0027] If there are test points B1 and B2 on the search curve with the same tangent direction as the test point, then calculate d1 as the difference between the angle between the line 5 connecting test point A1 and its corresponding test point B1 and the normal line 6 of test point A1, minus 90°. Similarly, calculate d2 as the difference between the angle between the line 7 connecting test point A2 and B2 and the normal line 8 of test point A2, minus 90°. If d1 If d2≤0, then the search point [i,i+1] on the search curve is the range of the starting point in the chord direction. If d1 If d2 > 0, it means that the search point [i, i+1] is not within the range of the chord starting point. Steps S301 and S302 need to be repeated to sequentially determine whether the range of the next search point of the search curve is within the range of the chord starting point.

[0028] In practice, test points A1 and A2 are determined to be the curve to be searched. When determining the corresponding test points B1 and B2, the search curve is also the curve to be searched. The process of obtaining test points B1 and B2 is as follows: S30201. On the search curve, search in reverse order from the end point to the beginning point until the searched point [j,j+1] is determined to be the range of the test point or the range of the searched point overlaps with the range of the test point. Specifically: if the slope of the tangent 9 of a certain test point is ≥ the slope of the tangent of the j-th searched point 10, and the slope of the tangent of the test point is ≤ the slope of the tangent of the (j+1)-th searched point 11, or if the slope of the tangent of a certain test point is ≤ the slope of the tangent of the j-th searched point 10, and the slope of the tangent of the test point is ≥ the slope of the tangent of the (j+1)-th searched point 11, then the range of the searched point [j,j+1] is the range of the test point; otherwise, sequentially determine whether the next range of the searched point is the range of the test point. If the range of the searched point overlaps with the range of the test point, it means that there is no other test point on the search curve with the same tangent direction as the test point other than the test point with the same tangent direction.

[0029] S30202. Determine whether the range of the measured point [j, j+1] meets the accuracy requirements of the measured point. If it does, then determine the measured point; if it does not, then locally encrypt the search curve between the j-th searched point 10 and the (j+1)-th searched point 11 to form an encrypted region. Repeat S30201 to S30202 within the encrypted region until the range of the measured point that meets the accuracy requirements of the measured point is calculated.

[0030] The method for determining whether the range of the searched point [j, j+1] meets the accuracy requirements of the measured point is as follows: if the absolute value of the angle 13 between the tangent 12 of the searched point j and the tangent of the searched point j and the tangent of the corresponding test point, and the absolute value of the angle 15 between the tangent 14 of the searched point j+1 and the tangent of the searched point j+1 and the tangent of the corresponding test point, are both less than the positioning accuracy threshold f of the measured point, then the range of the searched point [j, j+1] meets the accuracy requirements of the measured point and the measured point is calculated; otherwise, it does not meet the requirements.

[0031] The method for determining the test point is as follows: if the absolute value of the angle 13 between the tangent of the search point j and the tangent of its corresponding test point is less than the absolute value of the angle 15 between the tangent of the search point j+1 and the tangent of its corresponding test point, then the search point j is the test point; otherwise, the search point j+1 is the test point.

[0032] Step 4: Determine whether the chord starting point range [i, i+1] meets the chord accuracy threshold e. If it does, the chord direction can be determined and the installation angle can be calculated; if it does not, the search curve is locally densified between test point A1 and test point A2. Steps 3 and 4 are repeated in the densified area until the chord starting point range [i, i+1] meets the requirement of the chord accuracy threshold e.

[0033] Specifically, by judging the absolute values ​​of d1 and d2 in step S302, if both are less than the chordal accuracy threshold e, it means that the chordal starting point range [i, i+1] meets the chordal accuracy requirement; otherwise, it does not. By comparing the absolute values ​​of d1 and d2, if the absolute value of d1 is less than the absolute value of d2, then line 5 connecting A1B1 is determined to be the chordal direction; otherwise, line 7 connecting A2B2 is determined to be the chordal direction. The installation angle can be obtained by calculating the angle between the chordal direction and the axial direction in the overall coordinate system of the impeller machinery.

[0034] Step 5: Traverse the leaf profile curve and sequentially search for two chord length positioning points on the leaf profile curve whose tangents are perpendicular to the chord direction 16, denoted as C1 and C2 respectively. Obtain the tangent of the chord length positioning point C1 and its intersection point D1 with the chord direction, and the intersection point D2 of the tangent of the chord length positioning point C2 with the chord direction. Calculate the distance between the intersection points D1 and D2 to obtain the chord length.

[0035] Specifically, the search process for the two chord length positioning points whose tangents are perpendicular to the chord direction is as follows: S501. Starting from any position on the leaf-shaped curve, search sequentially in any direction until the searched point [k, k+1] is determined to be the range of chord length positioning points. Specifically, if the angle between the tangent of the k-th searched point and the chord direction is ≤90°, and the angle between the tangent of the (k+1)-th searched point and the chord direction is ≥90°, or the angle between the tangent of the k-th searched point and the chord direction is ≥90°, and the angle between the tangent of the (k+1)-th searched point and the chord direction is ≤90°, then the searched point range [k, k+1] is the range of chord length positioning points.

[0036] S502. Determine whether the range of chord length positioning points [k, k+1] meets the vertical accuracy requirement. If it does, determine the chord length positioning point; if it does not, locally refine the searched curve between the k-th searched point and the (k+1)-th searched point to form an encrypted region. Repeat S501 to S502 within the encrypted region until the range of chord length positioning points that meets the vertical accuracy requirement is calculated.

[0037] The method for determining whether the range of chord-length positioning points [k, k+1] meets the vertical accuracy requirement is as follows: calculate the difference between the angle between the tangent of the k-th searched point and the chord direction and 90°, which is s1; calculate the difference between the angle between the tangent of the (k+1)-th searched point and the chord direction and 90°, which is s2. If the absolute values ​​of s1 and s2 are both less than the vertical accuracy threshold g, then the range of chord-length positioning points [k, k+1] meets the vertical accuracy requirement.

[0038] The method for determining the chord length positioning point is as follows: compare the absolute values ​​of s1 and s2. If the absolute value of s1 is less than or equal to the absolute value of s2, then the searched point k is the chord length positioning point; otherwise, the searched point k+1 is the chord length positioning point.

[0039] Based on the same inventive concept, this invention also provides a system for calculating the airfoil mounting angle and chord length, as described in the following embodiments. Since the principle underlying the airfoil mounting angle and chord length calculation system is similar to the airfoil mounting angle and chord length calculation method disclosed in the above embodiments, the implementation of the airfoil mounting angle and chord length calculation system can refer to the implementation of the airfoil mounting angle and chord length calculation method, and repeated details will not be elaborated further. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0040] Figure 9 This is a structural block diagram of a calculation system for the blade installation angle and chord length disclosed in an embodiment of the present invention, as shown below. Figure 9As shown, the system includes an encryption preprocessing unit 901, a chord starting point search unit 902, a precision control unit 903, an installation angle calculation unit 904, and a chord length calculation unit 905. The structure is described below.

[0041] Specifically, the encryption preprocessing unit 901 is used to execute steps S1 and S2, to perform encryption sampling on the input blade profile to generate a discrete point sequence, and to determine the tangent direction and normal direction at each sampling point through the discrete point sequence; to obtain the axial coordinates of each sampling point on the blade profile according to the overall coordinate system of the turbomachinery, and to determine the blade profile on the blade head side between the minimum point of axial coordinates and the maximum point of axial coordinates as the test range. The chord starting point search unit 902 is used to perform step S3, searching for a pair of chord starting points that satisfy the chord geometric conditions within the test range. The chord geometric conditions are: there exists a pair of adjacent test points, and for each of the adjacent test points, a corresponding point with the same tangent direction can be found within the test range and at a position on the other side of the axial coordinate of that point; and the deviations between the direction of the line connecting each of the adjacent test points and its corresponding point and the normal direction satisfy the condition that the signs are opposite or at least one of the deviations is zero. The precision control unit 903 is used to execute steps S4 and S6 to determine whether the chord direction determined by the chord direction starting point pair meets the preset chord direction precision threshold; if it meets the threshold, the blade installation angle is calculated based on the chord direction; if it does not meet the threshold, the interval between the chord direction starting point pairs is locally encrypted, and a new chord direction starting point pair that meets the chord direction geometric conditions is searched again in the locally encrypted interval. The precision judgment and local encryption operation are repeated for the new chord direction starting point pair until a chord direction that meets the chord direction precision threshold is obtained. The installation angle calculation unit 904 is used to execute steps S5 and S6 to calculate the blade installation angle based on the chord direction, wherein the chord direction is the direction of the line connecting the point with the smaller absolute value of the centering deviation of the starting point of the chord direction and its corresponding point, and the blade installation angle is the angle between the chord direction and the axial direction in the overall coordinate system of the turbomachinery. The chord length calculation unit 905 is used to execute step S7, traverse the blade profile, sequentially search for two chord length positioning points on the blade profile whose tangents are perpendicular to the chord direction, extract the intersection points of the tangents of the two chord length positioning points and the chord direction respectively, and calculate the distance between the two intersection points to obtain the chord length.

[0042] Furthermore, the chord-direction starting point search unit supports traversal modes from the front end to the back end or from the back end to the front end of the test range, and performs reverse search accordingly in the rear or front segment of the leaf shape.

[0043] The embodiments of the present invention achieve the following technical effects: 1. This invention only requires the first derivative of the leaf-shaped curve to be continuous (i.e., the tangent direction exists and is continuous), without involving the calculation of the second derivative or curvature, thus avoiding noise amplification and numerical instability. The algorithm has a simple structure, good stability, fast convergence speed, and high calculation accuracy. 2. The method of the present invention is applicable to both traditional airfoils with standard circular arcs at the leading and trailing edges, and modern high-performance airfoils with ellipses, splines, or arbitrary free curvatures at the leading / tailing edges, breaking through the limitations of the traditional chord definition on geometric form; 3. This invention has a clear geometric meaning, is logically intuitive and easy to understand, is easy to program and implement, can be seamlessly integrated into CAD / CAM / CMM systems, supports automated high-precision blade installation angle calculation, and significantly improves the consistency and reliability of turbomachinery design and manufacturing.

[0044] In this embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described methods for calculating the arbitrary blade installation angle and chord length.

[0045] Specifically, the computer device can be a computer terminal, a server, or a similar computing device.

[0046] In this embodiment, a computer-readable storage medium is provided, which stores a computer program that performs the above-described methods for calculating any of the blade installation angles and chord lengths.

[0047] Specifically, computer-readable storage media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable storage media does not include transient media, such as modulated data signals and carrier waves.

[0048] Obviously, those skilled in the art should understand that the modules or steps of the above-described embodiments of the present invention can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the embodiments of the present invention are not limited to any particular hardware and software combination.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for calculating the blade installation angle and chord length, characterized in that, include: The input leaf profile is encrypted and sampled to generate a discrete point sequence. The tangent direction and normal direction at each sampling point are determined by the discrete point sequence. Based on the overall coordinate system of the turbomachinery, the axial coordinates of each sampling point on the blade profile are obtained, and the blade profile on the blade head side between the minimum point of the axial coordinate and the maximum point of the axial coordinate is determined as the test range. Within the test range, search for pairs of chord starting points that satisfy the chord geometry conditions, which are: there exists a pair of adjacent test points, and for each of the adjacent test points, a corresponding point with the same tangent direction can be found within the test range and at a position on the other side of the axial coordinate of that point; and the deviations between the direction of the line connecting each of the adjacent test points and its corresponding point and the normal direction satisfy the condition that the signs are opposite or at least one of the deviations is zero. Determine whether the chord starting point satisfies the preset chord accuracy threshold for the determined chord direction; If satisfied, the blade installation angle is calculated based on the chord direction. If not satisfied, the interval between the chord starting point pairs is locally encrypted, and a new chord starting point pair that satisfies the chord geometric conditions is searched again in the locally encrypted interval. The accuracy judgment and local encryption operation are repeated for the new chord starting point pairs until a chord that satisfies the chord accuracy threshold is obtained, and the blade installation angle is calculated based on the chord. Traverse the leaf-shaped contour, sequentially search for two chord length positioning points on the leaf-shaped contour whose tangents are perpendicular to the chord direction, extract the intersection points of the tangents of the two chord length positioning points and the chord direction respectively, and calculate the distance between the two intersection points to obtain the chord length.

2. The method for calculating the blade installation angle and chord length according to claim 1, characterized in that, The deviation is the value obtained by subtracting 90° from the angle between the direction of the line connecting the test point and its corresponding point and the normal direction of the test point.

3. The method for calculating the blade installation angle and chord length according to claim 1, characterized in that, The chordal geometric condition is determined by judging whether the product of two deviation values ​​is less than or equal to zero.

4. The method for calculating the blade installation angle and chord length according to claim 1, characterized in that, Searching for chord start pairs includes any of the following methods: Method 1: Traverse adjacent test point pairs sequentially from the front end to the back end of the test range, and for each test point in the adjacent test point pair, search for the corresponding point with the same tangent direction in the reverse direction in the latter half of the test range. Method 2: Traverse adjacent test point pairs sequentially from the end to the front of the test range, and for each test point in the adjacent test point pair, search for the corresponding point with the same tangent direction in the reverse direction in the first half of the test range.

5. The method for calculating the blade installation angle and chord length according to claim 4, characterized in that, For each test point, perform a reverse search for corresponding points with the same tangent direction, including: Traverse adjacent search point pairs in the reverse direction within the first or second half of the test range; If the tangent slope of the test point is between the tangent slopes of the two points in the current adjacent search point pair, then the interval between the adjacent search point pairs is taken as the candidate corresponding interval; If the accuracy of the candidate corresponding interval does not meet the preset corresponding point positioning accuracy threshold, then local encryption is performed within the candidate corresponding interval, and reverse search continues within the encrypted interval until a corresponding point that meets the corresponding point positioning accuracy threshold is obtained, wherein the corresponding point positioning accuracy threshold is < chordal accuracy threshold.

6. The method for calculating the blade installation angle and chord length according to claim 1, characterized in that, Calculate the blade installation angle based on the chord direction, including: Compare the absolute values ​​of the deviations between the lines connecting each point in the chord starting point pair or the new chord starting point pair and their corresponding points, select the line with the smaller absolute value as the chord direction, and calculate the angle between the chord direction and the axial direction in the overall coordinate system of the turbomachinery as the blade installation angle.

7. A calculation system for blade installation angle and chord length, characterized in that, include: The encryption preprocessing unit is used to perform encryption sampling on the input blade profile to generate a discrete point sequence, and to determine the tangent direction and normal direction at each sampling point through the discrete point sequence; the axial coordinates of each sampling point on the blade profile are obtained according to the overall coordinate system of the turbomachinery, and the blade profile on the blade head side between the minimum point of axial coordinates and the maximum point of axial coordinates is determined as the test range. The chord start point search unit is used to search for pairs of chord start points that satisfy the chord geometric conditions within the test range. The chord geometric conditions are: there exists a pair of adjacent test points, and for each of the adjacent test points, a corresponding point with the same tangent direction can be found within the test range and at a position on the other side of the axial coordinate of that point; and the deviations between the direction of the line connecting each of the adjacent test points and its corresponding point and the normal direction satisfy the condition that the signs are opposite or at least one of the deviations is zero. The precision control unit is used to determine whether the chord start point meets the preset chord accuracy threshold for the determined chord direction; if it does, the airfoil installation angle is calculated based on the chord direction. If not satisfied, the interval between the chord starting point pairs is locally encrypted, and a new chord starting point pair that satisfies the chord geometric conditions is searched again in the locally encrypted interval. The accuracy judgment and local encryption operation are repeated for the new chord starting point pairs until a chord that satisfies the chord accuracy threshold is obtained. The installation angle calculation unit is used to calculate the blade installation angle based on the chord direction, wherein the chord direction is the direction of the line connecting the point with the smaller absolute value of the centering deviation of the starting point of the chord direction and its corresponding point, and the blade installation angle is the angle between the chord direction and the axial direction in the overall coordinate system of the turbomachinery. The chord length calculation unit is used to traverse the leaf profile, sequentially search for two chord length positioning points on the leaf profile whose tangents are perpendicular to the chord direction, extract the intersection points of the tangents of the two chord length positioning points and the chord direction respectively, and calculate the distance between the two intersection points to obtain the chord length.

8. The calculation system for blade installation angle and chord length according to claim 7, characterized in that, The chord-direction starting point search unit supports traversal modes from the front end to the back end or from the back end to the front end of the test range, and performs reverse search accordingly in the rear or front segment of the leaf shape.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for calculating the blade installation angle and chord length as described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that performs the method for calculating the blade installation angle and chord length according to any one of claims 1 to 6.

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