A method for reconstructing a leading edge and a trailing edge model of an aeroengine blade
By reconstructing the leading and trailing edge models of aero-engine blades, increasing the contour allowance, and employing multi-axis CNC high-speed milling, the problem of easy damage to the leading and trailing edges of the blades was solved, achieving efficient and high-quality machining results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AECC AVIATION POWER CO LTD
- Filing Date
- 2023-10-31
- Publication Date
- 2026-05-29
Smart Images
Figure CN117454546B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aero-engine blade processing, specifically to a method for reconstructing the leading and trailing edge models of an aero-engine blade. Background Technology
[0002] The blade profiles of integral bladed disks and integral bladed rings for aero engines are complex free-form surfaces, currently widely machined using multi-axis CNC milling. However, due to the relatively small blade thickness and poor structural rigidity, especially at the leading and trailing edges, which are the weakest points of the blade (R=0.18mm at the thinnest points of the leading and trailing edges of some integral bladed disks and rings), the actual machining process is easily affected by factors such as machine tools and cutting tools, resulting in... Figure 1 , Figure 2 The blade's leading and trailing edge profiles shown are damaged, making it prone to edge trimming and necking during machining (e.g.) Figure 4 As shown), sharp edges (such as) Figure 5 (as shown) and blunt tip (as shown) Figure 6 The phenomenon shown is as follows: Figure 3 As shown, the edge ΔH is cut off in region L, and this profile seriously affects the aerodynamic performance of the overall bladed disk.
[0003] Improving the machining quality of the leading and trailing edge profiles of blades, ensuring smooth curvature, and avoiding damage during machining have become challenges in the processing of integral bladed disks and integral blade rings. Currently, engineers typically address this issue by optimizing machining parameters. When the tool reaches the leading and trailing edges, the rotational speed and feed rate are reduced (approximately half of the blade body machining parameters) to provide sufficient response time for the tool and machine tool, allowing the tool to cut according to the curvature profile of the leading and trailing edges.
[0004] The above methods can alleviate the current situation where the leading and trailing edge contours of blades are easily damaged to some extent, but they cannot completely avoid the problems of sharp edges and chipped edges that are easy to occur during machining. Moreover, it is common for most five-axis machining centers to reduce the speed and feed when milling the leading and trailing edges of blades, which reduces machining efficiency. Summary of the Invention
[0005] To address the problems existing in the prior art, this invention provides a method for reconstructing the leading and trailing edge models of an aero-engine blade. This method performs reverse compensation on the leading and trailing edges, which are prone to defects, increases the profile margin of the leading and trailing edges, and obtains a smoothly transitioned machining model. This ensures that the leading and trailing edges of the overall bladed disk maintain uniform and sufficient margin during machining, and that the dimensions of the leading and trailing edges meet the design requirements after machining.
[0006] This invention is achieved through the following technical solution:
[0007] A method for reconstructing the leading edge model of an aero-engine blade includes the following steps:
[0008] S1, convert a set of original data points on the blade profile into the original theoretical blade profile curve, draw a circle with the midpoint of the leading edge contour of the original theoretical blade profile curve as the center, and form the first and second division points far away from the leading edge contour on the original theoretical blade profile curve.
[0009] S2, connect the first and second dividing points to obtain line segment a1, then connect the midpoint of line segment a1 and the midpoint of the leading edge contour to obtain line segment b1. Extend all points on the leading edge contour in a direction parallel to line segment b1 away from line segment a1. The distance H between each extended point and line segment a1 is... 2i The distance H from the point and line segment a1 1i All satisfy: H 2i / H 1i =α, where α is a constant ≥ 1.2, to obtain the leading edge profile curve;
[0010] S3. Following the process described in S1 and S2, operate on several sets of original data points corresponding to the remaining cross-sections on the blade profile to obtain several leading edge profile curves. Construct all the leading edge profile curves into a leading edge model of the aero-engine blade, and complete the reconstruction of the leading edge model of the aero-engine blade.
[0011] Preferably, in S1, a set of original data points on the blade profile are imported into UG software for profile construction to obtain the original theoretical blade profile curve.
[0012] Preferably, when S1 is drawn as a circle, R1 is used as the radius. When the radius Rq corresponding to the front edge is less than 1.5 mm, R1 = 1.5 to 3Rq.
[0013] Preferably, when S1 is drawn as a circle, R1 is used as the radius. If the radius Rq corresponding to the leading edge is ≥1.5mm, then R1=Rq+0.5.
[0014] Preferably, in S2, α = (L1 + L2) / L1, where L1 is the length of line segment b1, and L2 ≤ the allowable tolerance on the leading edge of the design.
[0015] A method for reconstructing the trailing edge model of an aero-engine blade includes the following steps:
[0016] S1, convert a set of original data points on the blade profile into the original theoretical blade profile curve, draw a circle with the midpoint of the trailing edge contour of the original theoretical blade profile curve as the center, and form the third and fourth division points far away from the trailing edge contour on the original theoretical blade profile curve.
[0017] S2, connect the third and fourth dividing points to obtain line segment a2, then connect the midpoint of line segment a2 and the midpoint of the trailing edge contour to obtain line segment b2. Extend all points on the trailing edge contour in a direction parallel to line segment b2 away from line segment a2. The distance Q between each extended point and line segment a2 is... 2i The distance Q from the point and line segment a2 1i All satisfy: Q 2i / Q 1i =β, where β is a constant ≥1.2, to obtain the trailing edge profile curve;
[0018] S3. Following the process described in S1 and S2, operate on several sets of original data points corresponding to the remaining cross-sections on the blade profile to obtain several trailing edge profile curves. Construct all the trailing edge profile curves into a trailing edge model of the aero-engine blade, and complete the reconstruction of the trailing edge model of the aero-engine blade.
[0019] Preferably, in step S1, a set of original data points on the blade profile are imported into UG software for profile construction to obtain the original theoretical blade profile curve.
[0020] Preferably, S1 is a circle with radius R2. When the radius Rh corresponding to the trailing edge is less than 1.5 mm, R2 = 1.5 to 3Rh.
[0021] Preferably, S1 is drawn as a circle with radius R2. If the radius Rh corresponding to the trailing edge is ≥1.5mm, then R2=Rh+0.5.
[0022] Preferably, in S2, β=(M1+M2) / M1, where M1 is the length of line segment b2, and M2≤the allowable tolerance on the trailing edge of the design.
[0023] Compared with the prior art, the present invention has the following beneficial technical effects:
[0024] This invention discloses a method for reconstructing the leading and trailing edge models of aero-engine blades. First, a set of original data points on the blade profile to be machined is converted into the original theoretical blade profile curve. Then, segmentation points are obtained at positions outside the leading and trailing edge contours to reconstruct them. All points on the leading and trailing edge contours are extended along a fixed ratio, completing the digital model reconstruction for blade machining. This results in a smoothly transitioning machining model, ensuring uniform and sufficient allowance at the leading and trailing edges of the integral bladed disk and integral blade ring during machining. This effectively guarantees the leading and trailing edge profiles, avoids blade damage, and ensures that the dimensions of the leading and trailing edges meet design requirements after machining. This method adds machining surfaces and allowances at the leading and trailing edges through the reconstructed model, allowing for reverse compensation at defect locations. Using this model for multi-axis CNC high-speed milling ensures that the dimensions of the leading and trailing edges meet design requirements after machining, eliminating defects such as chipped edges, sharp edges, blunt ends, and necking, improving part yield, reducing rework and repair processes, and increasing machining efficiency. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of machining defects on the leading edge of a blade in the background art.
[0026] Figure 2 This is a schematic diagram of machining defects at the trailing edge of a blade in the background art.
[0027] Figure 3 This is a schematic diagram of machining defects during blade trimming in the background art.
[0028] Figure 4 This is a schematic diagram of the machining defects during blade necking in the background art.
[0029] Figure 5 This is a schematic diagram of machining defects when the blade has a sharp edge, as shown in the background art.
[0030] Figure 6 This is a schematic diagram of machining defects when the blade tip is blunt, as shown in the background art.
[0031] Figure 7 This is the theoretical airfoil curve obtained in step 1 of this invention.
[0032] Figure 8 This is a schematic diagram of the junction point between the leading edge reconstruction curve obtained in step 2 of the present invention and the theoretical airfoil curve.
[0033] Figure 9 This is the reference coordinate system obtained in step 3 of the present invention.
[0034] Figure 10 This is the reconstructed contour curve obtained in step 4 of the present invention.
[0035] Figure 11This is a schematic diagram of the leading edge curvature before adjustment in step 4 of the present invention.
[0036] Figure 12 This is a schematic diagram of the leading edge curvature after adjustment in step 4 of the present invention.
[0037] Figure 13 This is the blade leading edge model reconstructed in step 5 of the present invention.
[0038] In the figure: 1-leading edge, 2-tailing edge, 3-first dividing point, 4-second dividing point, 5-midpoint of leading edge profile, 6-X1 axis, 7-Y1 axis, 8-leading edge profile, 9-leading edge profile curve. Detailed Implementation
[0039] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.
[0040] This invention provides a method for reconstructing the leading and trailing edge models of an aero-engine blade, based on UG software, and includes the following steps;
[0041] Step (1), establish the theoretical airfoil curve:
[0042] A set of original data points of the aero-engine blade profile are imported into UG (Unigraphics) software for blade profile configuration, and converted into an original theoretical blade profile curve. Figure 7 Only the original theoretical airfoil curve including the leading edge is shown, and it will be referred to as theoretical airfoil curve a thereafter;
[0043] Step (2), determine the point where the leading (tail) edge reconstruction curve meets the original theoretical airfoil curve:
[0044] First, determine the point where the leading edge reconstruction curve meets the theoretical airfoil curve:
[0045] Draw a circle with radius R1 centered at the midpoint of the leading edge profile (i.e., the center of the arc of the theoretical airfoil curve a). The intersection points of this circle and the theoretical airfoil curve a are used as the first and second division points, respectively. Figure 8 As shown, the theoretical airfoil curve a is used to divide the leading edge position;
[0046] R1 is selected based on the size of the blade profile, and the value of R1 is generally selected within a certain range.
[0047] Specifically as follows:
[0048] R1 = 1.5Rq ~ 3Rq, where Rq < 1.5 mm. If Rq ≥ 1.5, then R1 = Rq + 0.5.
[0049] In the formula, Rq is the leading edge radius of the blade profile.
[0050] Different leaves have different Rq values.
[0051] Second, determine the point where the trailing edge reconstruction curve meets the theoretical airfoil curve:
[0052] The theoretical airfoil curves at the trailing edge position are divided in the same way, that is, a circle with the midpoint of the trailing edge profile as the center and a radius of R2 is drawn. The intersection of this circle and the theoretical airfoil curve are used as the third and fourth division points, respectively, to divide the theoretical airfoil curves at the trailing edge position.
[0053] R2 is selected based on the size of the blade profile. The value of R2 is generally selected within a certain range. The specific formula is as follows:
[0054] R2 = 1.5Rh ~ 3Rh, Rh < 1.5 mm; if Rh ≥ 1.5 mm, then R2 = Rh + 0.5; Rh is...
[0055] The radius of the trailing edge of the blade profile section;
[0056] Different leaves have different Rh values.
[0057] Step (3), construct the reference coordinate system for the leading (tail) edge reconstruction curve:
[0058] First, construct the reference coordinate system for the leading edge reconstruction curve:
[0059] Connect the first and second dividing points to obtain line segment a1. Then, use the midpoint of line segment a1 as the midpoint of line segment b1 to connect the midpoint of the leading edge contour, as shown below. Figure 9 As shown, the two straight lines are the X1 axis and the Y1 axis, respectively, which can be used as coordinate axes for subsequent adjustment of the leading edge profile;
[0060] Second, construct the reference coordinate system for the trailing edge reconstruction curve:
[0061] The coordinate axes for adjusting the trailing edge contour curve are obtained in the same way: connect the third and fourth division points to obtain line segment a2, and then use the midpoint of line segment a2 to draw line segment b2 to connect the midpoint of the leading edge contour. These two lines are the X2 axis and Y2 axis, respectively, which can be used as the coordinate axes for subsequent adjustment of the trailing edge contour.
[0062] Step (4): Adjust the front and rear edge contours:
[0063] First, adjust the leading edge contour:
[0064] The leading edge profile curve is adjusted using a non-uniform scaling mode. In the portion where it intersects with the theoretical airfoil curve a, the scaling factor is set to 1, meaning no scaling. Figure 10As shown, the direction to be extended and the scaling factor can be set according to actual needs. This method ensures that the adjusted leading edge profile curve has a smooth transition with the theoretical airfoil curve, and that the adjusted leading edge profile curve has a uniform rate of curvature change.
[0065] The direction to be extended is the positive direction of the Y1 axis, that is, away from line segment a1. Extend all points on the leading edge contour in a direction parallel to line segment b1 away from line segment a1. The distance H between each extended point and line segment a1 is... 2i The distance H from the point and line segment a1 1i All satisfy: H 2i / H 1i =δ, meaning that all points are operated on according to a common scaling factor to obtain the leading edge profile curve.
[0066] Scaling factor
[0067] In the formula, L1 is the distance between the midpoint of the straight line drawn from the first and second dividing points and the midpoint of the leading edge contour, i.e., the distance of line segment b1, and L2 ≤ the allowable tolerance on the leading edge according to the design. L2 can be adjusted within a certain range according to the processing requirements.
[0068] The curvature of the leading edge before adjustment was checked using UG software, and a curvature graph was drawn, such as... Figure 11 As shown.
[0069] The adjusted leading edge curvature is as follows Figure 12 As shown, the specific formula can be obtained as follows:
[0070]
[0071] In the formula: R q x is the radius of curvature q y q Let be the coordinates of the leading edge. x q and y q The specific expression can be determined based on different adjusted contour curves.
[0072] Therefore, it can be concluded that the curvature after adjustment is basically consistent with the curvature before adjustment.
[0073] Second, adjust the trailing edge profile curve:
[0074] The adjusted trailing edge profile curve was obtained using the same method, and the curvature after adjustment remained essentially the same as the curvature before adjustment. The specific process is as follows:
[0075] The trailing edge profile curve is adjusted using a non-uniform scaling mode. In the section where it intersects with the theoretical airfoil curve, the scaling factor is set to 1 (no scaling). In the direction where extension is needed, the scaling factor can be set according to actual requirements. This method ensures a smooth transition between the adjusted trailing edge profile curve and the theoretical airfoil curve, and that the adjusted trailing edge profile curve has a uniform rate of curvature change.
[0076] The direction to be extended is the positive Y2 axis, that is, away from line segment a2. Extend all points on the trailing edge contour in a direction parallel to line segment b2 away from line segment a2. The distance Q between each extended point and line segment a2 is... 2i The distance Q from the point and line segment a1 1i All satisfy: That is, all points are operated on according to a common scaling factor to obtain the trailing edge profile curve.
[0077] Scaling factor
[0078] In the formula, M1 is the distance between the midpoint of the straight line drawn from the third and fourth dividing points and the midpoint of the trailing edge profile, i.e., the distance of line segment b2, and M2 ≤ the allowable tolerance on the trailing edge in the design. M2 can be adjusted within a certain range according to the processing requirements.
[0079] The leading edge profile is replaced by the leading edge profile curve, and the trailing edge profile is replaced by the trailing edge profile curve to form the reconstructed theoretical airfoil curve.
[0080] Step (5) forms the leading and trailing edge reconstruction model:
[0081] The blade profile can generally be divided into several sections, each corresponding to a set of original data points. Steps (1) to (4) are repeated several times. The same operation is performed on the remaining sections corresponding to several sets of original data points to obtain the adjusted leading and trailing edge profile curves of each section, thereby forming several reconstructed theoretical blade profile curves. The leading and trailing edge models are constructed through all these processed leading and trailing edge profile curves to form the leading and trailing edge reconstruction models. Figure 13 A specific leading edge reconstruction model is presented.
Claims
1. A method for reconstructing the leading edge model of an aero-engine blade, characterized in that, Includes the following steps: S1. Transform a set of original data points on the blade profile into the original theoretical blade profile curve. Draw a circle with the midpoint of the leading edge contour of the original theoretical blade profile curve as the center. When drawing the circle, use R1 as the radius. When the radius Rq corresponding to the leading edge is less than 1.5mm, R1 = 1.5~3Rq. When the radius Rq corresponding to the leading edge is greater than or equal to 1.5mm, R1 = Rq + 0.
5. Form the first and second division points far away from the leading edge contour on the original theoretical blade profile curve. S2, connect the first and second dividing points to obtain line segment a1, then connect the midpoint of line segment a1 and the midpoint of the leading edge contour to obtain line segment b1. Extend all points on the leading edge contour in a direction parallel to line segment b1 away from line segment a1. The distance H between each extended point and line segment a1 is... 2i The distance H from the point and line segment a1 1i All satisfy: H 2i / H 1i =α, where α is a constant ≥ 1.2, and α = (L1 + L2) / L1, where L1 is the length of line segment b1, and L2 ≤ the allowable tolerance of the leading edge in the design, thus obtaining the leading edge profile curve; S3. Following the process described in S1 and S2, operate on several sets of original data points corresponding to the remaining cross-sections on the blade profile to obtain several leading edge profile curves. Construct all the leading edge profile curves into a leading edge model of the aero-engine blade, and complete the reconstruction of the leading edge model of the aero-engine blade.
2. The method for reconstructing the leading edge model of an aero-engine blade according to claim 1, characterized in that, In S1, a set of original data points on the blade profile are imported into UG software for profile construction to obtain the original theoretical blade profile curve.
3. A method for reconstructing the trailing edge model of an aero-engine blade, characterized in that, Includes the following steps: S1. A set of original data points on the blade profile is converted into the original theoretical blade profile curve. A circle is drawn with the midpoint of the trailing edge profile of the original theoretical blade profile curve as the center and R2 as the radius. When the radius Rh corresponding to the trailing edge is less than 1.5 mm, R2 = 1.5~3Rh. If the radius Rh corresponding to the trailing edge is greater than or equal to 1.5 mm, R2 = Rh + 0.
5. The third and fourth division points are formed on the original theoretical blade profile curve, which are far away from the trailing edge profile. S2, connect the third and fourth dividing points to obtain line segment a2, then connect the midpoint of line segment a2 and the midpoint of the trailing edge contour to obtain line segment b2. Extend all points on the trailing edge contour in a direction parallel to line segment b2 away from line segment a2. The distance Q between each extended point and line segment a2 is... 2i The distance Q from the point and line segment a2 1i All satisfy: Q 2i / Q 1i =β, where β is a constant ≥1.2, and β=(M1+M2) / M1, where M1 is the length of line segment b2, and M2≤the allowable tolerance on the trailing edge in the design, thus obtaining the trailing edge profile curve; S3. Following the process described in S1 and S2, operate on several sets of original data points corresponding to the remaining cross-sections on the blade profile to obtain several trailing edge profile curves. Construct all the trailing edge profile curves into a trailing edge model of the aero-engine blade, and complete the reconstruction of the trailing edge model of the aero-engine blade.
4. The method for reconstructing the trailing edge model of an aero-engine blade according to claim 3, characterized in that, S1 imports a set of original data points on the blade profile into UG software for profile construction to obtain the original theoretical blade profile curve.