CN115168986A - Method for acquiring geometric characteristic parameters of blade section - Google Patents
Method for acquiring geometric characteristic parameters of blade section Download PDFInfo
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- CN115168986A CN115168986A CN202210673124.0A CN202210673124A CN115168986A CN 115168986 A CN115168986 A CN 115168986A CN 202210673124 A CN202210673124 A CN 202210673124A CN 115168986 A CN115168986 A CN 115168986A
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- G06F30/10—Geometric CAD
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- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
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- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
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- G06F30/27—Design optimisation, verification or simulation using machine learning, e.g. artificial intelligence, neural networks, support vector machines [SVM] or training a model
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- G06F—ELECTRIC DIGITAL DATA PROCESSING
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- G06F2111/06—Multi-objective optimisation, e.g. Pareto optimisation using simulated annealing [SA], ant colony algorithms or genetic algorithms [GA]
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- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/02—Reliability analysis or reliability optimisation; Failure analysis, e.g. worst case scenario performance, failure mode and effects analysis [FMEA]
Abstract
The invention relates to a method for acquiring geometric characteristic parameters of a blade section, belonging to the technology of engine blades; the method comprises the steps of adjusting the size of the section of the blade according to the maximum value and the minimum value of the coordinate point and setting the position of the section of the blade; cutting the front edge and the tail edge of the blade, and adjusting the cut discrete points to initial positions to obtain adjusted suction surface profile and pressure surface profile of the blade; firstly fitting the pressure surface molded line and the suction surface molded line of the blade to obtain the approximate points of the front edge and the tail edge of the blade; according to the approximate points of the front edge and the tail edge of the blade, the junction point of the front edge and the tail edge of the blade and the molded lines of the suction surface and the pressure surface is obtained, and then the real molded lines of the suction surface and the pressure surface are obtained; accurately fitting the pressure surface molded line and the suction surface molded line of the blade to obtain accurate front and tail edge points of the blade; and obtaining the geometric characteristic parameters of the section of the blade. The method can quickly calculate the geometric characteristic parameters of the blade section and ensure the accuracy of the calculation result, and meanwhile, the calculation process is simple and the application range is wide, so that the accurate acquisition of the geometric characteristic parameters of the blade section is completed.
Description
Technical Field
The invention belongs to the technical field of engine blades, and particularly relates to a method for acquiring geometric characteristic parameters of a blade section.
Background
The blades are the most numerous parts and the largest production quantity in the aeroengine, wherein the bending, twisting and sweeping degrees of the blades of the compressor are larger, so that the processing difficulty is higher. Due to the influences of factors such as machining vibration and internal strain of a workpiece in the machining process, a certain geometric deviation exists between the actually machined blade and the designed reference blade, and therefore the machining quality of the blade needs to be detected in a mode of acquiring geometric characteristic parameters of the blade.
Meanwhile, a large number of researches show that the processing deviation of the blade can affect the performance of the compressor and even the whole engine. Document [ 1] (Wu C Y. Orbital Surface vane Milling and flash SAM in the Design and Manufacturing of Jet Engine Fan and Compressor air, ASME Turbo Expo2012, 2012) found that a machining variation of 0.0254mm to 0.0762mm in some areas of a large Fan blade was sufficient to affect the service performance and life of the blade. The method for detecting the machining quality of the blade comprises the steps of establishing a machining deviation probability distribution model of the blade, and obtaining a large number of geometric characteristic parameters of the actually machined blade, wherein the geometric characteristic parameters of each section of the blade are obtained.
Most of the existing methods adjust the position of a control point on the blade section in an iterative manner and fit the section, so as to obtain the geometric parameters of the blade section (Koilongli, high-conservation, liminxia. Particle swarm optimization algorithm solves the non-uniform rational B spline curve fitting of the optimal control point, and is applied by a computer 2022). Taking an Autoblade module in the NUMECA software package as an example, the Fitting module provided by the Autoblade module performs Fitting and continuous optimization on the blade model to obtain each parameter value closest to the target geometry. However, due to the fact that the curvature of the blade changes greatly near the leading edge and the trailing edge, most fitting methods provided by the method have a 'head-off' condition at the leading edge and the trailing edge of the blade, and the radius errors of the obtained leading edge and the trailing edge of the blade are large. In comparison, the simulated annealing method provided by the module can obtain a more accurate fitting result, but the method is more complex, takes longer time for fitting, and is difficult to apply to the acquisition of the geometric parameters of the large-scale cross sections.
Meanwhile, the number of control points on the blade section cannot be too large due to the phenomenon of "overfitting" (Laube P, franz M O, umlauf G. Deep learning parameter for B-spline curve improvement, IEEE, 2018.). Also taking the Autoblade module as an example, when the number of control points on the molded line exceeds 30, a "necking" phenomenon occurs near the junction of the leading edge and the trailing edge with the molded lines of the suction surface and the pressure surface. The limited number of control points also brings errors to the acquisition of the maximum thickness and the relative position of the maximum thickness of the blade.
In the prior art, the acquisition of the geometric characteristic parameters of the section of the blade is difficult to realize in large batch through the prior art, and the acquisition is limited by a software acquisition channel, so that the application range is not wide. However, since it is difficult to obtain the geometric parameters of the actually processed blade, most of the research on the aerodynamic performance of the compressor, which is influenced by the profile deviation, is often developed by assuming the probability distribution of a certain type of processing deviation of the blade according to experience through the blade processing standard in the industry. The research method has certain theoretical value, but because the geometric characteristic parameters of the blade section are difficult to extract and a real blade processing deviation probability distribution model cannot be established, the research method is difficult to directly generate guidance value for the blade processing process.
Disclosure of Invention
The technical problem to be solved is as follows:
in order to avoid the defects of the prior art, the invention provides the method for acquiring the geometric characteristic parameters of the blade section, and the method for fitting the blade profile curve and interpolating is used for acquiring the geometric characteristic parameters of the blade section, so that the method can ensure simple calculation process, wide application range, high operation efficiency and high calculation precision, and can realize accurate acquisition of the geometric characteristic parameters of the blade section.
The technical scheme of the invention is as follows: a method for acquiring geometric characteristic parameters of a blade section is characterized by comprising the following specific steps:
step 1: inputting three-dimensional coordinates of each discrete point on the blade profile section, adjusting the size of the blade section according to the maximum value and the minimum value of the coordinate points, and setting the position of the blade section;
and 2, step: cutting the front edge and the tail edge of the blade, and adjusting the cut discrete points to initial positions to obtain adjusted suction surface profile and pressure surface profile of the blade;
and step 3: firstly fitting the pressure surface molded line and the suction surface molded line of the blade to obtain the approximate points of the front edge and the tail edge of the blade;
and 4, step 4: according to the blade leading edge and trailing edge approximate points obtained in the step 3, obtaining junction points of the leading edge and the trailing edge of the blade and molded lines of the suction surface and the pressure surface, and further obtaining real molded lines of the suction surface and the pressure surface;
and 5: accurately fitting the pressure surface molded line and the suction surface molded line of the blade obtained in the step (4) to obtain accurate front and tail edge points of the blade;
step 6: and obtaining the geometric characteristic parameters of the section of the blade.
The invention further adopts the technical scheme that: in the step 2, the front edge and the tail edge of the blade are cut off according to the relative positions of the front edge and the tail edge of the blade in the chord length direction of the blade.
The invention further adopts the technical scheme that: in the step 2, when cutting off the tail edge of the blade, the region behind 95% of the chord length is cut off, when cutting off the front edge of the compressor blade, the region 5% before the chord length is cut off, and when cutting off the front edge of the turbine blade, the region 10% to 15% before the chord length is cut off.
The further technical scheme of the invention is as follows: in the step 3, obtaining a discrete point set of the profile of the suction surface and the profile of the pressure surface of the blade according to the cutting positions of the front edge and the tail edge of the blade, respectively carrying out curve fitting on the profile of the suction surface and the profile of the pressure surface of the blade, and then carrying out equidistant interpolation on the obtained curves; and calculating by utilizing the insertion points on the suction surface and pressure surface molded lines to obtain the mean camber line of the blade, and extending the mean camber line to obtain the leading edge point and the trailing edge point of the blade.
The further technical scheme of the invention is as follows: in the step 4, according to the distance between each discrete point of the blade section and the approximate points of the front edge and the tail edge of the blade obtained in the step 3, each junction point of the front edge and the tail edge of the blade and the molded lines of the suction surface and the pressure surface is judged.
The further technical scheme of the invention is as follows: in the step 5, obtaining a discrete point set of the molded surfaces of the suction surface and the pressure surface of the blade according to the junction point, respectively carrying out curve fitting on molded lines of the suction surface and the pressure surface of the blade, and then carrying out equidistant interpolation on the obtained curves; and calculating by utilizing the insertion points on the suction surface profile and the pressure surface profile to obtain the mean camber line of the blade, and prolonging the mean camber line to obtain the leading edge point and the trailing edge point of the blade.
The further technical scheme of the invention is as follows: and 6, calculating the chord length and the mounting angle of the blade according to the front edge point and the tail edge point obtained in the step 5.
The further technical scheme of the invention is as follows: and 6, calculating according to the leading edge point and the trailing edge point obtained in the step 5 and the boundary point obtained in the step 4 to obtain the radius of the leading edge and the trailing edge of the blade and the circle center of the leading edge and the trailing edge.
The invention further adopts the technical scheme that: and 6, obtaining the thickness distribution, the maximum thickness and the maximum thickness position of the blade according to the insertion points on the suction and pressure surface profile of the blade obtained in the step 5.
Advantageous effects
The invention has the beneficial effects that: the invention determines the camber line, the front edge point and the tail edge point of the blade through curve fitting and interpolation, and further solves each geometric characteristic parameter of the blade section. Meanwhile, the thickness distribution of the blade can be accurately obtained as much as possible by an interpolation method, and the relative position of the maximum thickness of the blade is determined. The method has the advantages that the geometric characteristic parameters of the blade section can be rapidly calculated, the accuracy of the calculation result is guaranteed, meanwhile, the calculation process is simple, the application range is wide, and therefore the geometric characteristic parameters of the blade section can be accurately acquired.
Taking a 50% blade height section of Rotor 37 as an example, the design chord length is 55.8mm, the installation angle is-50 degrees, the radius of the front edge is 0.183mm, the radius of the tail edge is 0.175mm, the maximum thickness is 3.1mm, and the relative position of the maximum thickness is 0.52.
The chord length calculated by using an Autoblade module through a simulated annealing method is 55.801mm, the installation angle is-50.02 degrees, the radius of the leading edge is 0.1822mm, the radius of the trailing edge is 0.1791mm, the maximum thickness is 30.995mm, and the relative position of the maximum thickness is 0.5893. The fitting time was about 4 minutes 20 seconds.
The chord length obtained by calculation of the invention is 55.76mm, the installation angle is-49.98 degrees, the radius of the leading edge is 0.1826mm, the radius of the trailing edge is 0.1745mm, the maximum thickness is 3.102mm, and the relative position of the maximum thickness is 0.5196. The relative errors of the geometric characteristic parameters and the design parameters obtained by calculation are less than 0.3 percent, and the calculation precision is high. The calculation process of the present invention takes only 46 seconds.
From the comparison of the fitting result of the Autoblade module and the calculation result of the invention, although the chord length error obtained by the invention is slightly larger, the chord length error is also controlled within the high confidence interval. The accuracy of acquiring the leading edge radius, the trailing edge radius and the maximum thickness position of the blade is obviously higher. Meanwhile, the method obviously reduces the calculation time required for acquiring the geometric parameters of the single section, which provides favorable conditions for acquiring the geometric parameters of the large-batch sections.
Drawings
FIG. 1 is a schematic diagram showing the comparison between the size and position of the cross section before and after adjustment.
Fig. 2 shows the primary fitting process.
FIG. 3 is a schematic diagram of the profile of the suction and pressure surfaces and the mean camber line of the first fit mid-section.
FIG. 4 is a schematic diagram showing the distribution of distances between discrete points near the leading edge of the cross-section and the leading edge point.
Fig. 5 is a second exact fit process.
FIG. 6 is a schematic diagram of the precise fit of the profile and camber line of the suction and pressure surfaces of the midsection.
FIG. 7 is a schematic view of the front and rear edge points, the front and rear edge center points, and the boundary point of the blade section.
FIG. 8 is a schematic view of a blade cross-sectional thickness profile.
Fig. 9 shows the overall process of the invention.
Detailed Description
The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes the specific implementation process of the invention in detail by combining the acquisition result of the geometric characteristic parameters of the 50% blade height section of the NASA Rotor 37 blade.
Step 1: and inputting three-dimensional coordinates of discrete points on the blade profile section. Generally, two curves of the profile of the suction and pressure surfaces are given in the geometric model file and during engineering measurement, and both the curves take the vicinity of the leading edge as the starting point and the vicinity of the trailing edge as the ending point. Therefore, the sequence of the discrete points of the two curves needs to be adjusted first, so that the discrete points of the two curves are connected end to end in sequence to form a complete leaf shape. The default arrangement sequence of the discrete points is clockwise arrangement by taking the vicinity of the tail edge as a starting point, and the three-dimensional coordinates of the discrete points at the moment are respectively marked as matrixes X1, Y1 and Z1 according to three directions of coordinate axes, wherein the axial coordinates of the discrete points are recorded in the matrix X1, Y1 is a circumferential coordinate, and Z1 is a radial coordinate. Since the radial position of each discrete point on the same blade height section varies little, Z1 can be ignored in subsequent processing to reasonably simplify the calculation process.
Finding the minimum value and the maximum value xmin1 and xmax1 in X1 and the positions minld1 and maxld1, regarding the discrete point with coordinates (X1 (minld 1), Y1 (minld 1)) as the nominal leading edge point LE1, and regarding the discrete point with coordinates (X1 (maxld 1), Y1 (maxld 1)) as the nominal trailing edge point TE1.
Firstly, the leaf profile is integrally translated, so that the LE1 point is coincided with the coordinate origin. The airfoil is then rotated about the LE1 point so that the line connecting the LE1 point and the TE1 point coincides with the x-axis coordinate. And finishing the initial adjustment of the leaf profile position, and recording the two-dimensional coordinates of each discrete point after the adjustment as matrixes X2 and Y2 respectively.
Positions minld2 and maxld2 where the minimum value and the maximum value in the X2 are located are found, and a discrete point between an axial coordinate interval of (X2 (minld 2), 0.8 × X2 (minld 2) +0.2 × X2 (maxld 2)) is regarded as a leading edge vicinity point, and a discrete point in the interval where the Y value is minimum is regarded as LE2. Discrete points in the axial coordinate interval between (0.2 × X2 (minld 2) +0.8 × X2 (maxld 2), X2 (maxld 2)) are regarded as points near the trailing edge, and the discrete point with the smallest Y value in this interval is denoted as TE2.
And rotating the leaf profile around an LE2 point to enable a connecting line of the LE2 point and the TE2 point to be parallel to the coordinate X axis, and recording the two-dimensional coordinates of each discrete point after adjustment as matrixes X3 and Y3 respectively. Finding the minimum and maximum values xmin3 and xmax3 in X3, and the minimum value ymin3 in Y3, and finally adjusting the leaf profile position through the translation and scaling process:
X4(i)＝(X3(i)-xmin3)/(xmax3-xmin3)
Y4(i)＝(Y3(i)-ymin3)/(xmax3-xmin3)
where i is the order of the discrete points of the leaf profile. At this time, the leaf patterns have been scaled to x to [0,1], y to [0, + ∞ ]. The size and position pairs before and after the profile adjustment are shown in fig. 1. At the moment, the problem of installation angles of the blades does not need to be considered when the front edges and the tail edges of the blades are cut off, and the problem that the length difference between the suction surface molded lines and the pressure surface molded lines is too large after the front edges and the tail edges of the blades are cut off is solved.
And 2, step: the leading and trailing edges of the blade are cut off. The leading and trailing edges of the blade are cut out according to their relative positions in the chord length direction of the blade, and regions where x to [0,0.03] and x to [0.97,1] are located in Rotor 37 can be regarded as the leading and trailing edges of the blade.
After cutting off the front and tail edge points of the blade, adjusting the size and position of the blade to the initial state in the reverse order in the step 1, and dividing the discrete points into four molded lines by a curve connected end to end at the moment. Recording two-dimensional coordinates of discrete points on the suction surface profile as matrixes XS1 and YS1 respectively; the two-dimensional coordinates of the discrete points on the pressure surface profile are respectively recorded as matrices XP1 and YP1. Recording two-dimensional coordinates of the cut discrete points of the front edge as matrixes XL1 and YL1 respectively; the two-dimensional coordinates of the discrete points of the excised trailing edge are recorded as matrices XT1, YT1, respectively. The starting positions of the suction and pressure surface molded lines of the blade obtained at the moment are influenced by the cutting positions of the front edge and the tail edge in the step 2, and the suction surface molded lines are not true and have the function of laying the dividing points in the step 4.
And step 3: and respectively fitting the pressure surface molded line and the suction surface molded line by using a 9-order Polynomial fitting method. After the fitting is completed, the minimum value, the maximum value xpmin1 and the maximum value xpmax1 in the matrix XP1 are obtained, equidistant interpolation is carried out on the pressure surface fitting curve from the front edge to the tail edge in the interval [ xpmin1, xpmax1], and the two-dimensional coordinates of the interpolation on the pressure surface fitting curve are recorded as matrixes XP2 and YP2 respectively. In the same way, the suction surface fitting curve can be subjected to interpolation, and the two-dimensional coordinates of the interpolation on the suction surface fitting curve are respectively recorded as matrixes XS2 and YS2. According to the test that the influence of different interpolation points on the calculation precision in the earlier stage is known, the accuracy of acquiring the geometric characteristic parameters can be ensured by 200 interpolation points.
The two-dimensional coordinate matrix of the discrete points of the mean camber line can be obtained by the insertion points on the fitting curves of the suction surface and the pressure surface:
XC1(i)＝(XS2(i)+XP2(i))/2
YC1(i)＝(YS2(i)+YP2(i))/2
wherein i is the sequence of each discrete point of the mean camber line and the insertion point of the suction surface and the pressure surface. The mean camber line was fitted using a 9 th order Polynomial fitting method through 200 discrete points in the mean camber line from the leading edge to the trailing edge direction. After the fitting is finished, equidistant interpolation is carried out on the mean camber line fitting curve from the front edge to the tail edge in the interval [ xmin1, xmax1], the number of the interpolation points is 2000, and two-dimensional coordinates of the interpolation points on the mean camber line fitting curve are respectively marked as matrixes XC2 and YC2.
The matrix elements smaller than 0.8 x xmin1+0.2 x xmax1 in XC2 are marked as a matrix XC3, the corresponding matrix elements in YC2 are marked as a matrix YC3, and XC3 and YC3 are two-dimensional coordinate matrixes of camber line interpolation points near the front edge. Similarly, the matrix elements larger than 0.2 x xmin1+0.8 x xmax1 in XC2 are recorded as a matrix XC4, the corresponding matrix elements in YC2 are recorded as a matrix YC4, and XC4 and YC4 are two-dimensional coordinate matrices of the camber line interpolation points near the trailing edge.
The distance between each interpolation point of the camber line near the front edge and each discrete point of the front edge is calculated and compared to find the front edge point of the blade:
where h is the distance between two points, i is the order of mean camber line insertions near the leading edge, and j is the order of discrete points of the leading edge. When h is the minimum value, XL1 (j) and YL1 (j) corresponding to h are blade leading edge points, which are marked as LEP1, and coordinates of the LEP1 and ylep1 are marked as (ylep 1). Similarly, the blade trailing edge point TEP1 can be found by calculating and comparing the distance between each interpolation point of the mean camber line near the trailing edge and each discrete point of the trailing edge, and the coordinates are marked as (xtep 1, ytep 1).
And 4, step 4: and calculating and comparing the distance between each discrete point of the leading edge and the leading edge point LEP1 of the blade. The distribution of the distances between the discrete points of the leading edge and the leading edge point of the blade is shown in fig. 4, and it can be seen that the distances between the discrete points and the leading edge point before and after the intersection point are changed very obviously. The discrete point where the first obvious change occurs is the boundary point LTP between the leading edge and the pressure surface, and the discrete point where the second obvious change occurs is the boundary point LTS between the leading edge and the suction surface. In the same way, the boundary points between the trailing edge and the suction and pressure surfaces can be respectively obtained and are respectively marked as TTS and TTP.
A suction surface type line is arranged between the LTS and the TTS, and two-dimensional coordinates of each discrete point are recorded as matrixes XS3 and YS3; a pressure surface molded line is arranged between the LTP and the TTP, and two-dimensional coordinates of each discrete point are recorded as matrixes XP3 and YP3; a blade leading edge is arranged between the LTS and the LTP, and two-dimensional coordinates of each discrete point are marked as matrixes XL3 and YL3; the blade trailing edge is arranged between TTS and TTP, and the two-dimensional coordinates of each discrete point are recorded as matrixes XT3 and YT3. At this time, the initial positions of the profile of the suction surface and the profile of the pressure surface of the blade, which are obtained, are not influenced by the cutting positions of the front edge and the tail edge in the step 2, and the profile can be regarded as a real profile of the suction surface.
And 5: similar to the method in step 3, fitting the pressure surface molded line and the suction surface molded line by using a 9-order Polynomial fitting method respectively. After the fitting is finished, equidistant interpolation points are carried out on the fitting curves of the suction surface and the pressure surface of the blade, and two-dimensional coordinates of the interpolation points on the fitting curves of the pressure surface are recorded as matrixes XP4 and YP4 respectively; and recording the two-dimensional coordinates of the insertion points on the suction surface fitting curve as matrixes XS4 and YS4 respectively.
The two-dimensional coordinate matrix of the discrete points of the mean camber line can be obtained by the insertion points on the fitting curves of the suction surface and the pressure surface:
XC5(i)＝(XS4(i)+XP4(i))/2
YC5(i)＝(YS4(i)+YP4(i))/2
wherein i is the sequence of each discrete point of the mean camber line and the insertion point of the suction surface and the pressure surface. The mean camber line was fitted using a 9 th order Polynomial fitting method through discrete points on the mean camber line. After the fitting is finished, equidistant interpolation is carried out on the mean camber line fitting curve from the front edge to the tail edge in an interval [ xmin1, xmax1], and two-dimensional coordinates of interpolation points on the mean camber line fitting curve are marked as matrixes XC6 and YC6 respectively.
The matrix elements smaller than 0.8 x xmin1+0.2 x xmax1 in XC6 are marked as a matrix XC7, the corresponding matrix elements in YC6 are marked as a matrix YC7, and XC7 and YC7 are two-dimensional coordinate matrixes of camber line interpolation points near the leading edge. Similarly, the matrix elements larger than 0.2 x xmin1+0.8 x xmax1 in XC6 are marked as a matrix XC8, the corresponding matrix elements in YC6 are marked as a matrix YC8, and XC8 and YC8 are two-dimensional coordinate matrixes of the mean arc interpolation points near the trailing edge.
The distance between each interpolation point of the camber line near the front edge and each discrete point of the front edge is calculated and compared to find the front edge point of the blade:
where h is the distance between two points, i is the order of the mean camber line interpolation points near the leading edge, and j is the order of the discrete points of the leading edge. When h is the minimum value, XL3 (j) and YL3 (j) corresponding to h are the blade leading edge points, which are marked as LEP, and the coordinates of LEP are marked as (ylep ). Similarly, the blade trailing edge point TEP can be found by calculating and comparing the distance between each interpolation point of the mean camber line near the trailing edge and each discrete point of the trailing edge, and the coordinates of the TEP are marked as (xtep, ytep).
And 6: according to the front edge point LEP and the tail edge point TEP, the Chord length Chord and the mounting angle Gamma of the blade can be calculated:
because the three points determine a circle and the distances from the circle center to the three points are the same, the radius of the leading edge of the blade and the circle center of the leading edge can be calculated through the LEP of the leading edge and the LTS and LTP of the junction points; and calculating the radius of the tail edge of the blade and the center of the circle of the tail edge through the TEP of the tail edge and the TTS and TTP of the junction points.
According to the insertion points on the suction surface profile and the pressure surface profile of the blade, the thickness distribution, the maximum thickness and the maximum thickness position of the blade can be obtained.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.
Claims (9)
1. A method for acquiring geometric characteristic parameters of a blade section is characterized by comprising the following specific steps:
step 1: inputting three-dimensional coordinates of each discrete point on the blade profile section, adjusting the size of the blade section according to the maximum value and the minimum value of each coordinate point, and setting the position of the blade section;
and 2, step: cutting off the front edge and the tail edge of the blade, and adjusting the cut discrete points to the initial position to obtain the adjusted suction surface profile and the adjusted pressure surface profile of the blade;
and step 3: firstly fitting the pressure surface molded line and the suction surface molded line of the blade to obtain the approximate points of the front edge and the tail edge of the blade;
and 4, step 4: according to the blade leading edge and trailing edge approximate points obtained in the step 3, obtaining junction points of the leading edge and the trailing edge of the blade and molded lines of the suction surface and the pressure surface, and further obtaining real molded lines of the suction surface and the pressure surface;
and 5: accurately fitting the pressure surface molded line and the suction surface molded line of the blade obtained in the step (4) to obtain accurate front and tail edge points of the blade;
step 6: and obtaining the geometric characteristic parameters of the section of the blade.
2. The method for acquiring the geometric characteristic parameters of the cross section of the blade according to claim 1, wherein the method comprises the following steps: and in the step 2, the front edge and the tail edge of the blade are cut according to the relative positions of the front edge and the tail edge of the blade in the chord length direction of the blade.
3. The method for acquiring the geometric characteristic parameters of the cross section of the blade according to claim 2, wherein the method comprises the following steps: in the step 2, when cutting off the tail edge of the blade, the region behind 95% of the chord length is cut off, when cutting off the front edge of the compressor blade, the region 5% before the chord length is cut off, and when cutting off the front edge of the turbine blade, the region 10% to 15% before the chord length is cut off.
4. The method for acquiring the geometric characteristic parameters of the cross section of the blade according to claim 1, wherein the method comprises the following steps: in the step 3, a discrete point set of the profiles of the suction surface and the pressure surface of the blade is obtained according to the cutting positions of the front edge and the tail edge of the blade, curve fitting is respectively carried out on the profiles of the suction surface and the pressure surface of the blade, and then equidistant interpolation points are carried out on the obtained curve; and calculating by utilizing the insertion points on the suction surface and pressure surface molded lines to obtain the mean camber line of the blade, and extending the mean camber line to obtain the leading edge point and the trailing edge point of the blade.
5. The method for acquiring the geometric characteristic parameters of the cross section of the blade according to claim 1, wherein the method comprises the following steps: in the step 4, the boundary points of the front edge and the tail edge of the blade and the molded lines of the suction surface and the pressure surface are judged according to the distance between each discrete point of the blade section and the approximate points of the front edge and the tail edge of the blade obtained in the step 3.
6. The method for obtaining the geometric characteristic parameters of the section of the blade according to claim 1, wherein: in the step 5, obtaining a discrete point set of the molded surfaces of the suction surface and the pressure surface of the blade according to the junction point, respectively carrying out curve fitting on molded lines of the suction surface and the pressure surface of the blade, and then carrying out equidistant interpolation on the obtained curves; and calculating by utilizing the insertion points on the suction surface profile and the pressure surface profile to obtain the mean camber line of the blade, and prolonging the mean camber line to obtain the leading edge point and the trailing edge point of the blade.
7. A method for obtaining blade section geometric feature parameters according to any one of claims 1 to 6, wherein: and 6, calculating the chord length and the mounting angle of the blade according to the front edge point and the tail edge point obtained in the step 5.
8. The method for obtaining the geometric characteristic parameters of the section of the blade according to any one of claims 1 to 6, wherein: and 6, calculating according to the leading edge point and the trailing edge point obtained in the step 5 and the junction point obtained in the step 4 to obtain the radius of the leading edge and the trailing edge of the blade and the circle center of the leading edge and the trailing edge.
9. A method for obtaining blade section geometric feature parameters according to any one of claims 1 to 6, wherein: and 6, obtaining the thickness distribution, the maximum thickness and the maximum thickness position of the blade according to the insertion points on the suction and pressure surface profile line of the blade obtained in the step 5.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115841548A (en) * | 2023-02-21 | 2023-03-24 | 陕西空天信息技术有限公司 | Computer-aided generation method and system of blade model |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115841548A (en) * | 2023-02-21 | 2023-03-24 | 陕西空天信息技术有限公司 | Computer-aided generation method and system of blade model |
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