Chamfering Modeling Method and Machining Method for Compressor Blades

Abstract

The present invention discloses a chamfering modeling method and a machining method for a compressor blade. The chamfering modeling method includes the following steps: inputting a basic model of a compressor blade without chamfers including a shroud; determining a plurality of chamfer arcs in the chamfer region on the basic model; respectively selecting a plurality of points on each chamfer arc according to the same rule, connecting the points at corresponding positions on the plurality of chamfer arcs to form a closed curve, and obtaining the blade profile curve of the chamfer region; replacing the blade profile curve at the corresponding position in the basic model with the obtained blade profile curve of the chamfer region to obtain a blade model with chamfers. By using the above method to perform chamfering modeling on the design model of the compressor blade, the present invention effectively guarantees the integrity of the blade profile curve in the chamfer region of the design model of the compressor blade, avoids the "breakage" situation that occurs when directly chamfering using CAD / CAM software, and thus facilitates subsequent strength calculation and production manufacturing using this design model.

Description

Technical Field

[0001] The present invention relates to a chamfering modeling method and a machining method for a compressor blade. Background Art

[0002] In the compressor components of aeroengines, gas turbines, and ground axial compressors, rotor blades and stator blades are common components. Chamfering the compressor blade at its blade root and blade tip is a very important task for both design and manufacturing. Before manufacturing the compressor blade, strength calculations are carried out to avoid the compressor blade not meeting the service strength. The strength calculation of the compressor blade is generally carried out in relevant software, which requires a complete design model of the compressor blade. The complete design model of the compressor blade is generally obtained by first drawing a basic model, and then chamfering the blade root and blade tip of the basic model of the compressor blade through CAD / CAM (Computer Aided Design and Computer Aided Manufacturing) software. The method of chamfering the basic model of the compressor blade through CAD / CAM may have a "breakage" phenomenon, which will cause problems for subsequent blade strength calculations and also affect the machining effect during subsequent manufacturing. Summary of the Invention

[0003] The technical problem to be solved by the present invention is the defect that the method of chamfering the basic model of the compressor blade through CAD / CAM in the prior art may have "breakage", affecting subsequent blade strength calculations and manufacturing, and provides a chamfering modeling method and a machining method for a compressor blade.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] The present invention provides a chamfering modeling method for a compressor blade. A rim table of the compressor blade is integrally formed at the blade root and / or blade tip of the compressor blade. The connection between the compressor blade and the rim table has a chamfer with a radius of R. The chamfering modeling method includes the following steps:

[0006] S1. Input the basic model of the compressor blade without chamfering including the rim table;

[0007] S2. Determine one of the chamfer arcs in the chamfering area on the basic model: Select three adjacent points A, B, and C on the blade profile at the blade root and / or blade tip of the compressor blade, with point A located between points B and C. Select a point D on the blade profile above point A. Select a point E on the rim table close to point A along the meridional view direction of the compressor blade. Calculate the coordinates of the center M and radius R of the sphere S1 passing through points A, B, C, and D M and the coordinates of the center N and radius R of the sphere S2 passing through points A, B, C, and EN ;

[0008] Calculate the coordinates of the center point P of the spherical ball S3 that is tangent to the spherical balls S1 and S2, obtain the tangent point T1 of the spherical ball S3 and the blade surface of the compressor blade and the tangent point T2 of the spherical ball S3 and the flange surface. The circular arc with the center at P and the radius R passing through the tangent point T1 and the tangent point T2 is the chamfering circular arc;

[0009] S3. Repeat step S2 to determine multiple chamfering circular arcs in the circumferential direction of the compressor blade;

[0010] S4. Select multiple points on each chamfering circular arc according to the same rule, connect the points at the corresponding positions on the multiple chamfering circular arcs to form a closed curve, and obtain the blade profile of the chamfering area;

[0011] S5. Replace the blade profile at the corresponding position in the basic model with the blade profile of the obtained chamfering area to obtain a blade model with chamfers.

[0012] In this solution, by adopting the above method, it is possible to effectively ensure the integrity of the blade profile of the chamfering area in the designed model of the compressor blade after chamfering, avoid the "breakage" situation that occurs when directly chamfering using CAD / CAM software, and thus facilitate the subsequent strength calculation and production manufacturing using this designed model.

[0013] Preferably, in step S2, the coordinates of the center point M of the spherical ball S1 are (x M , y M , z M ), and the coordinates of the center point N of the spherical ball S2 are (x N , y N , z N ). Then, the coordinates of the center point P of the spherical ball S3 are (x P , y P , z P ) and are obtained through the following steps:

[0014] S21. Calculate the initial value P0 coordinates (x P0 , y P0 , z P0 ) of the center point P, where: the center point P is located on the angular bisector of the straight line AD and the straight line AE, and the distances from the center point P to the straight line AD and AE are both R;

[0015] S22. List the system of equations:

[0016]

[0017] where:

[0018]

[0019]

[0020] S23. Solve the above equation: If there is only one solution, then this solution is the coordinate of the sphere center P; if there are two solutions, then the solution with a smaller distance from point P0 is the coordinate of the sphere center P.

[0021] Preferably, the tangent point T1 is located on the straight line connecting the sphere center P and the sphere center M and is at a distance of R from the sphere center P, and the tangent point T2 is located on the straight line connecting the sphere center P and the sphere center N and is at a distance of R from the sphere center P.

[0022] In this solution, through the above method, the upper boundary of the chamfered arc on the blade surface of the compressor blade and the lower boundary on the shroud surface can be quickly obtained.

[0023] Preferably, in step S4, fairing treatment is performed on the blade profile of the obtained chamfered area.

[0024] In this solution, fairing treatment is adopted to make the chamfering effect better.

[0025] Preferably, step S5 further includes the following steps:

[0026] S51. Determine the upper blade profile and the lower blade profile in the basic model of the compressor blade that are the same as the blade profile at the upper boundary and the blade profile at the lower boundary of the chamfered arc respectively;

[0027] S52. Correspondingly replace all the blade profiles between the upper blade profile and the lower blade profile in the basic model of the compressor blade with the blade profiles of the chamfered area obtained in step S4, and then the blade model with a chamfer is obtained.

[0028] Preferably, point A, point B, and point C should be located on the same side of the compressor blade.

[0029] In this solution, selecting point A, point B, and point C on the same side of the compressor blade makes the obtained result more accurate.

[0030] Preferably, after step S5, the following steps are further included:

[0031] S6. Generate the blade profile coordinate points of the blade model with a chamfer and output them.

[0032] In this solution, generating the blade profile coordinate points of the blade model with a chamfer can be input into a numerical control machine tool for machining the compressor blade.

[0033] The present invention also provides a machining method for a compressor blade, and the machining method includes chamfering the blade root and / or the blade tip of the compressor blade by using the chamfering modeling method of the compressor blade as described above.

[0034] Preferably, the processing method further includes the following steps:

[0035] Generate blade profile coordinate points from the blade model with chamfers.

[0036] Input the blade profile coordinate points into a numerical control machine tool, start the machining of the numerical control machine tool, and obtain the compressor blade.

[0037] The positive and progressive effects of the present invention are as follows: By using the above method to perform chamfer modeling on the design model of the compressor blade, the present invention can effectively ensure the integrity of the blade profile in the chamfered area of the design model of the compressor blade after chamfering, avoid the "breakage" situation that occurs when directly chamfering using CAD / CAM software, and thus facilitate subsequent strength calculation and production manufacturing using this design model. Description of the Drawings

[0038] Figure 1 It is a schematic flow chart of the chamfer modeling method of the compressor blade in the preferred embodiment of the present invention.

[0039] Figure 2 It is a schematic diagram of the chamfer modeling of the compressor blade in the preferred embodiment of the present invention.

[0040] Figure 3 It is a schematic diagram of selecting and determining the coordinate points of the centers of the spheres S1 and S2 on the compressor blade in the preferred embodiment of the present invention.

[0041] Figure 4 It is a schematic diagram of the position of the sphere S3 in the preferred embodiment of the present invention.

[0042] Figure 5 It is a schematic diagram of the initial value calculation of the center of the sphere S3 in the preferred embodiment of the present invention.

[0043] Figure 6 It is a schematic diagram of a situation of the relative positions of the sphere S3 and the spheres S1 and S2 in the preferred embodiment of the present invention.

[0044] Figure 7 It is a schematic diagram of another situation of the relative positions of the sphere S3 and the spheres S1 and S2 in the preferred embodiment of the present invention.

[0045] Description of the Reference Numerals:

[0046] Compressor blade 100

[0047] Blade surface 101

[0048] Flange 200

[0049] Flange surface 201

[0050] Chamfered area 300 Specific embodiments

[0051] The present invention will be more clearly and completely described below by way of examples in conjunction with the accompanying drawings, but the present invention is not limited to the scope of these examples thereby.

[0052] An axial compressor refers to a multi-stage compression device in which the air flow direction is the same as or nearly the same as the axis direction of the working wheel rotation, and is composed of a root tip flow channel and a series of stator-rotor blades arranged alternately. It is commonly used in aeroengines or gas turbines; the combination of adjacent stator and rotor blades is called a stage. Both the stator blades and the rotor blades are called compressor blades.

[0053] As Figure 2 shown, for the convenience of installing the compressor blade 100, a flange 200 of the compressor blade 100 is integrally formed at the root and / or tip of the compressor blade 100. There is generally a chamfer at the connection between the compressor blade 100 and the flange 200. Due to the usage scenario of the compressor blade 100, it is necessary to ensure the machining accuracy of the compressor blade 100. Generally, automated machining equipment is used for production, which requires ensuring the integrity of the design model of the compressor blade 100 to avoid the lack of coordinate points of the blade profile curve derived from the design model and affecting the machining.

[0054] As Figures 1-5 shown, this embodiment discloses a chamfer modeling method for the compressor blade 100. By adopting this chamfer modeling method, the integrity of the blade profile curve of the design model of the compressor blade 100 in the chamfer region 300 can be effectively ensured, and the situation of damage to the design model can be avoided, so as to facilitate the subsequent strength calculation and production manufacturing using the design model. As Figure 1 shown, the chamfer modeling method for the compressor blade 100 includes the following steps: The chamfer modeling method includes the following steps:

[0055] S1. Input the basic model of the compressor blade 100 without chamfer including the flange 200. The basic model of the compressor blade 100 can be obtained by the aerodynamic design method.

[0056] S2. Assume that the chamfer radius in the chamfer region 300 is R, and determine one of the chamfer arcs in the chamfer region 300 of the basic model.

[0057] As Figure 3As shown, three adjacent points A, B, and C are selected on the blade profile line at the blade root and / or blade tip of the compressor blade 100. Point A is located between point B and point C. A point D is selected on the blade profile line above point A. A point E is selected on the shroud 200 near point A along the meridional view direction of the compressor blade 100 (the meridional view direction refers to the circumferential direction when the compressor blade 100 rotates). Calculate the coordinates of the center M and the radius R of the sphere S1 passing through points A, B, C, and D. M And the coordinates of the center N and the radius R of the sphere S2 passing through points A, B, C, and E. N ;

[0058] Calculate the coordinates of the center P of the sphere S3 tangent to the spheres S1 and S2, obtain the tangent point T1 of the sphere S3 and the surface of the compressor blade 100, and the tangent point T2 of the sphere S3 and the surface of the shroud 201. The circular arc with the center P and the radius R passing through the tangent point T1 and the tangent point T2 is the chamfering circular arc.

[0059] Among them, the tangent point T1 is located on the straight line connecting the center P and the center M and is at a distance of R from the center P. The tangent point T2 is located on the straight line connecting the center P and the center N and is at a distance of R from the center P. Through the above method, the upper boundary of the chamfering circular arc on the blade surface 101 of the compressor blade 100 and the lower boundary on the surface of the shroud 201 can be obtained quickly.

[0060] S3. Repeat step S2 to determine multiple chamfering circular arcs in the circumferential direction of the compressor blade 100. In this step, as many chamfering circular arcs as possible are determined in the circumferential direction of the compressor blade 100 so that the blade profile line in the chamfering area 300 is smoother. In the above chamfering modeling steps, the chamfering modeling can be first performed on the pressure side of the blade of the compressor blade 100, and then the same method is used for the suction side of the blade of the compressor blade 100 and the leading and trailing edge areas. Of course, it is also possible to first select the suction side of the blade of the compressor blade 100 or the leading and trailing edge areas for chamfering modeling, which is not specifically limited here.

[0061] S4. Select multiple points on each chamfering circular arc according to the same rule, connect the points at the corresponding positions on the multiple chamfering circular arcs to form a closed curve, and obtain the blade profile line of the chamfering area.

[0062] In this step, it is assumed that N points (including the end points at both ends of the chamfering circular arc) are uniformly selected on each chamfering circular arc. The points at the corresponding positions on each chamfering circular arc are connected into a closed curve in the circumferential direction, and the blade profile lines in N chamfering areas 300 can be obtained. Among them, the upper boundary and the lower boundary of the blade profile line in the chamfering area 300 are the closed curves formed by the end points at both ends of the chamfering circular arc.

[0063] The airfoil at the upper boundary of the airfoil profile of the chamfered region 300 is the plane within the closed curve formed by all the tangent points of the spherical ball S1 and the blade surface 101. The airfoil at the lower boundary of the airfoil profile of the chamfered region 300 is the plane within the closed curve formed by all the tangent points of the spherical ball S1 and the surface 201 of the flange 200.

[0064] The airfoil section between the upper and lower boundaries within the chamfered region 300 is the plane within the closed curve formed by N - 2 points with the same label after removing the two end points of the chamfered arc from the airfoil profile line of the chamfered region 300.

[0065] S5. Replace the airfoil profile line of the compressor blade 100 at the corresponding position in the basic model with the airfoil profile line of the obtained chamfered region 300 to obtain a blade model with a chamfer.

[0066] In this solution, by adopting the above method, the integrity of the airfoil profile line of the chamfered region 300 of the design model of the compressor blade 100 can be effectively guaranteed, and the situation of damage to the design model can be avoided, thus facilitating the subsequent strength calculation and production manufacturing using this design model.

[0067] Specifically, in step S2, the coordinates of the center M of the sphere S1 are automatically obtained through calculation or programming software as (x M , y M , z M ). The coordinates of the center N of the sphere S2 are (x N , y N , z N ). Then the coordinates of the center P of the spherical ball S3 are (x P , y P , z P ) and are obtained through the following steps:

[0068] S21. Calculate the initial value P0 coordinates (x P0 , y P0 , z P0 ) of the center P of the sphere, where: the center P of the sphere is located on the angular bisector of the straight line AD and the straight line AE, as shown in Figure 5 , and the distances from the center P of the sphere to the straight lines AD and AE are both R;

[0069] S22. List the system of equations:

[0070]

[0071] Where:

[0072]

[0073]

[0074] S23. Solve the above equation: If there is only one solution, this solution is the coordinate of the center of the sphere P; if there are two solutions, the solution with a smaller distance from point P0 is the coordinate of the center of the sphere P.

[0075] As Figure 6 shown, the distance from the initial value of point P to the center of the sphere M is greater than R M , and the distance from the initial value of point P to the center of the sphere N is greater than R N .

[0076] As Figure 7 shown, the distance from the initial value of point P to the center of the sphere M is less than R M , and the distance from the initial value of point P to the center of the sphere N is less than R N .

[0077] In step S4 of this embodiment, fairing is performed on the blade profile of the obtained chamfered region 300. Using fairing makes the chamfering effect better.

[0078] Of course, in other embodiments, fairing may not be performed. Specifically, it can be determined by the designer according to the specific situation after chamfering the design model.

[0079] In this embodiment, step S5 further includes the following steps:

[0080] S51. Determine the upper blade profile and the lower blade profile in the basic model of the compressor blade 100 that are the same as the blade profile at the upper boundary and the lower boundary of the chamfered arc respectively;

[0081] S52. Replace all the blade profiles between the upper blade profile and the lower blade profile in the basic model of the compressor blade 100 with the blade profiles of the chamfered region 300 obtained in step S4, and the blade model with chamfers is obtained.

[0082] In this embodiment, point A, point B, and point C should be located on the same side of the compressor blade 100. Selecting point A, point B, and point C on the same side of the compressor blade 100 makes the obtained result more accurate.

[0083] Preferably, after step S5, the following steps are further included:

[0084] S6. Generate and output the blade profile coordinate points of the blade model with chamfers. Generating the blade profile coordinate points of the blade model with chamfers can be input into a numerical control machine tool for machining the compressor blade 100.

[0085] The present invention also discloses a machining method for a compressor blade 100, and the machining method includes chamfering the blade root and / or the blade tip of the compressor blade 100 by using the above-mentioned chamfering modeling method for the compressor blade 100.

[0086] Specifically, the processing method of the compressor blade 100 further includes the following steps:

[0087] Generate the blade profile coordinate points from the blade model with chamfers;

[0088] Input the blade profile coordinate points into the numerical control machine tool and start the machining of the numerical control machine tool to obtain the compressor blade 100.

[0089] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that this is only an example. The protection scope of the present invention is defined by the appended claims. Without departing from the principle and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A chamfering method for a compressor blade, characterized in that At the root and / or tip of the compressor blade, a shroud of the compressor blade is integrally formed. At the connection between the compressor blade and the shroud, there is a chamfer with a radius of R. The chamfer modeling method includes the following steps: S1. Input the basic model of the compressor blade without chamfer including the shroud. S2. Determine one of the chamfer arcs in the chamfer region of the basic model: Select three adjacent points A, B, and C on the blade profile at the blade root and / or blade tip of the compressor blade, where point A is between point B and point C. Select a point D on the blade profile above point A. Select a point E on the rim platform near point A along the meridian view direction of the compressor blade. Calculate the coordinates of the center M and the radius R of the sphere S1 passing through points A, B, C, and D M and the coordinates of the center N and the radius R of the sphere S2 passing through points A, B, C, and E N ; Calculate the coordinates of the center P of the sphere S3 that is tangent to the spheres S1 and S2, obtain the tangent point T1 of the sphere S3 and the blade surface of the compressor blade, and the tangent point T2 of the sphere S3 and the shroud surface. The circular arc with the center P and radius R passing through the tangent points T1 and T2 is the chamfer circular arc. S3. Repeat step S2 to determine multiple chamfer circular arcs in the circumferential direction of the compressor blade. S4. Select multiple points on each chamfer circular arc according to the same rule, connect the points at the corresponding positions on the multiple chamfer circular arcs to form a closed curve, and obtain the blade profile of the chamfer area. S5. Replace the blade profile at the corresponding position in the basic model with the blade profile of the chamfer area obtained, and obtain the blade model with chamfer.

2. The chamfering method of the compressor blade according to claim 1, characterized in that In step S2, the coordinates of the center M of the sphere S1 are (x M , y M , z M ), and the coordinates of the center N of the sphere S2 are (x N , y N , z N ). Then, the coordinates of the center P of the sphere S3 are (x P , y P , z P ) are obtained through the following steps: S21. Calculate the initial value \(P_0\) coordinates \((x\) P0 , y\) P0 , z\) P0 ) of the center of the sphere \(P\), where: The center of the sphere \(P\) is located on the angular bisector of the straight lines \(AD\) and \(AE\), and the distances from the center of the sphere \(P\) to the straight lines \(AD\) and \(AE\) are both \(R\); S22. List the equations: Where: S23. Solve the above equations: If there is only one solution, this solution is the coordinates of the center P; if there are two solutions, the solution with a smaller distance from the point P0 is the coordinates of the center P.

3. The chamfering shaping method of the compressor blade according to claim 1, characterized in that, The tangent point T1 is located on the straight line connecting the center P and the center M and is at a distance of R from the center P. The tangent point T2 is located on the straight line connecting the center P and the center N and is at a distance of R from the center P.

4. The chamfering method of the compressor blade according to claim 1, characterized in that In step S4, smooth the blade profile of the chamfer area obtained.

5. The chamfering method of the compressor blade according to claim 1, characterized in that Step S5 further includes the following steps: S51. Determine the upper blade profile and the lower blade profile in the basic model of the compressor blade that are the same as the blade profile at the upper boundary and the lower boundary of the chamfer circular arc respectively. S52. Replace all the blade profiles between the upper blade profile and the lower blade profile in the basic model of the compressor blade with the blade profile of the chamfer area obtained in step S4, and then the blade model with chamfer is obtained.

6. The chamfering modeling method of the compressor blade according to claim 1, characterized in that, Points A, B, and C should be on the same side of the compressor blade.

7. The chamfering method of the compressor blade according to claim 1, wherein After step S5, the following steps are further included: S6. Generate the blade profile coordinate points of the blade model with chamfer and output them.

8. A processing method for a compressor blade, characterized in that, The processing method includes chamfering the root and / or tip of the compressor blade by using the chamfer modeling method of the compressor blade as described in any one of claims 1-6.

9. The processing method of the compressor blade according to claim 8, characterized in that, The processing method further includes the following steps: Generate the blade profile coordinate points of the blade model with chamfer; Input the blade profile coordinate points into a numerical control machine tool, start the numerical control machine tool for processing, and obtain the compressor blade.

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