Blade body molded surface air inlet and outlet edge rounding follow-type quantitative extension method

Abstract

The invention relates to the technical field of precise modeling of blade molded surfaces, in particular to a method for rounding, following and quantitative lengthening of air inlet and outlet edges of a blade molded surface of a blade. The method comprises the following steps: step 1, constructing a complete section theoretical model; step 2, extending along the shape following direction and establishing a new fillet of an air inlet edge; step 3, extending along the shape following direction and establishing an air outlet edge fillet; and step 4, constructing an air inlet and air outlet fillet contour by using the newly established fillet, and completing the construction of a new section. The method has the advantages that the precision of the numerical control milling molded surface of the blade is improved, the machining error of the blade profile contour is reduced, particularly the contour shape of the air inlet edge and the air outlet edge is optimized, and the final quality of a product is improved by using the rounding follow-up quantitative extension method for the air inlet edge and the air outlet edge of the blade body molded surface of the air compressor. The method has been popularized to the machining process of all blades, and the qualified rate of final products of the blades is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of precise blade profile shaping, and in particular to a method for quantitatively extending the rounded intake and exhaust edges of a blade body profile. Background Art

[0002] With the development of industrial technology, blade profiles are becoming increasingly thin, light, rigid, and highly complex, with bending and twisting characteristics. This has led to increasingly poor machining rigidity and machinability. When CNC milling blade profiles, vibration rebound and overcutting are common, leading to excessive milling errors and out-of-tolerance corner rounding on the inlet and exhaust edges.

[0003] In order to ensure the accuracy of the fillet of the inlet and exhaust edges of the profile, the method of modifying the processing model is adopted to make reverse compensation for the fillet of the inlet and exhaust edges of the profile, so as to process qualified products. Summary of the Invention

[0004] The rigidity of the blade profile inlet and outlet edge area varies greatly. CNC milling will cause the inlet and outlet edge profile area to thicken and the edge R area to thin. Figure 1 As shown in the figure, the profile accuracy of the profile is reduced. At the same time, the surface roughness after CNC milling is uneven, which easily leads to increased material removal on the exhaust edge during subsequent surface polishing, further reducing the final processing accuracy of the profile and the qualified rate of parts.

[0005] To reduce machining errors in profile accuracy, the present invention also addresses the issue of increased material removal in the R region of the airfoil's intake and exhaust edges during the polishing process. This requires developing a new shaping method that quantitatively extends the R profile of the airfoil's intake and exhaust edges along the tangent line of the profile surface. This ensures the profile accuracy of the machined airfoil's intake and exhaust edges meets the technical requirements of the design drawings. This method relates to the field of CNC milling model correction.

[0006] The quantitative extension of the inlet and exhaust edge fillet of the compressor blade profile needs to be broken down into several steps:

[0007] Step 1: Construct a complete cross-section theoretical model. The specific procedure is as follows:

[0008] Step 1.1 First read in the surface coordinate points and draw the blade basin and back contour lines PF1 and PF2 for the first time.

[0009] According to the format requirements of the modeling software, a surface coordinate point data file is prepared and read in to form the blade basin and back contour lines PF1 and PF2.

[0010] Step 1.2: Construct the intake and exhaust edge fillets C1 and C2.

[0011] According to the center position coordinates and radius values ​​provided in the design drawings, construct the inlet and exhaust edge fillets C1 and C2.

[0012] Step 1.2: Create a tangent line through two fillets and construct a tangent point.

[0013] Take the coordinate point of the fillet C1 and C2 close to the intake and exhaust edges as a point through which the tangent passes, and make tangent lines L1, L2, L3, and L4 of circles C1 and C2 to form tangent points P201, P202, P203, and P204.

[0014] Step 1.3: Construct the leaf basin and leaf back cross-section lines PF1 and PF2.

[0015] Construct the blade basin profile line PF1: starting from one of the tangent points P201, connecting to the other tangent point P202 through the design coordinate point.

[0016] Construct the leaf back profile line PF2: start from one of the tangent points P203, connect to the other tangent point P204 through the design coordinate point and end.

[0017] Step 1.4 Construct the tangent fillet profiles PF3 and PF4

[0018] By designing the coordinates P51, P52, .....P95, P96, and ending at the tangent point P202, the tangent fillet contours PF3 and PF4 are constructed.

[0019] Step 1.5 Connect the four profiles to construct the complete theoretical section PF5

[0020] As shown, select PF1, PF2, PF3, and PF4 in sequence to construct the theoretical cross-sectional profile PF5.

[0021] Step 2: Extend along the contour direction and create a new fillet on the intake edge:

[0022] Step 2.1 Construct the midline L5 of the two tangent lines

[0023] Select the inlet edge fillet and the nearest edge point to construct two tangent lines L1 and L3, and construct the midline L5 of the two tangent lines

[0024] Step 2.2 determines that the extension direction of the two mid-line is the conformal direction.

[0025] The following direction is defined in the program: the following direction of the air intake edge is the extension direction of the straight line L5.

[0026] In step 2.3, the extended distance is assigned a value of #L11 in the model building program, with an initial value of 0.05 to 0.1.

[0027] Assign the X-axis and Y-axis coordinate values ​​of the center of the newly created intake edge fillet C3. The center coordinate offset value is (#XA1, #YA1). The offset value is the product of the cosine function value and the sine function value of the angle between the extended distance and the straight line L5, that is:

[0028] #XA1=#L11*COS(#A1), the extended value of the X-axis is the product of the cosine function value of the angle A1 between #L11 and the straight line L5.

[0029] #YA1=#L11*SIN(#A1), the Y-axis extension value is the angle between #L11 and line L5

[0030] The product of the values ​​of the long sine function of degree A1.

[0031] P135, C3, the center of the intake side fillet C3 is defined as point P135

[0032] P136, P135, TR, IX#XA1, IY#YA1, the coordinate value of point P136 is the displacement of point P135

[0033] (#XA1, #YA1).

[0034] Step 2.4 Create a new intake edge fillet C3

[0035] With the newly created intake edge center point as the center, construct the intake edge fillet C3 with the theoretical radius of the design drawing.

[0036] Step 3: Extend along the contour direction and create a fillet on the exhaust edge:

[0037] Follow the same steps as step 2 to construct the intake edge fillet C4 with the theoretical radius of the design drawing;

[0038] Step 4: Use the newly created fillet to construct the intake and exhaust fillet contours to complete the construction of the new section.

[0039] Step 4.1 Establish tangent lines to the newly constructed intake and exhaust edge fillets C3 and C4, and find the new tangent points P205, P206, P207, and P208

[0040] Select the inlet edge fillet and the nearest edge point at the basin and back section data points to construct four tangent lines L5, L6, L7, and L8 to form new tangent points P205, P206, P207, and P208

[0041] Step 4.2 Construct the new leaf basin and leaf back profile lines

[0042] With the newly constructed tangent points P205, P206, P207, and P208 as the starting and ending points, the profile lines PF6 and PF7 of the leaf basin and leaf back are constructed.

[0043] Step 4.3 Construct new intake and exhaust edge contours

[0044] Construct the intake and exhaust edge contour lines PF8 and PF9 through the new tangent points.

[0045] Step 4.4 Construct a new section line

[0046] Select the newly constructed blade basin (blade back) profile line and intake (exhaust) edge contour line in turn and connect them to form a new complete profile PF10.

[0047] Advantages of the present invention:

[0048] The method for rounding and quantitatively extending the inlet and outlet edges of blade airfoil profiles described in this invention improves the accuracy of CNC milled blade profiles, reduces blade profile machining errors, and particularly optimizes the profile shape of the inlet and outlet edges, improving final product quality. This method has been extended to all blade machining processes, significantly increasing the final product qualification rate.

[0049] Figures in the specification

[0050] Figure 1 , Schematic diagram of blade profile;

[0051] Figure 2 , quantitative schematic diagram of the rounded and directional extension of the intake edge;

[0052] Figure 3 , schematic diagram comparing the quantitative results of the exhaust edge rounding and directional extension. DETAILED DESCRIPTION

[0053] The present invention will be further explained below in conjunction with specific implementation plans, but the present invention is not limited thereto. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they have no technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0054] Example

[0055] like Figure 1 、 2 As shown in Figure 3, the total length of a new engine blade profile is 340 mm, the blade chord length is 110, the maximum thickness is about 4.50, the inlet and exhaust edge fillet area is rigid, and the tool allowance is small, resulting in the exhaust edge profile machining error greater than 0.14, which cannot meet the process requirements.

[0056] The processing method to improve the processing accuracy of this part is to use the method of quantitative extension of rounding. In the technical solution steps 2 and 3, the value of #L11=0.02 and #L22=0.02 are adjusted. This value is the effective experience value accumulated in the processing of the blade, which can indeed improve the surface contour accuracy. The specific implementation method is as follows:

[0057] Step 1: Construct a complete cross-section theoretical model. The procedure is as follows:

[0058]

[0059]

[0060] Step 2: Extend along the direction of shape #A1 and create an intake edge fillet model. Assign a value of 0.02 to #L11. The procedure is as follows:

[0061] Step 3: Extend along the direction of shape #A2 and create a fillet model for the exhaust edge. Assign a value of 0.02 to #L22. The procedure is as follows:

[0062]

[0063]

[0064] Step 4: Use the newly created fillet to create the intake and exhaust fillet contours. This completes the construction of the new section.

[0065]

[0066] Matters not covered by the present invention are known technologies.

[0067] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for quantitatively extending the rounded inlet and outlet edges of a blade airfoil profile, characterized in that: The method for quantitatively extending the rounded inlet and outlet edges of the blade body profile is decomposed into multiple steps: Step 1: Construct a complete cross-section theoretical model. The specific procedure is as follows: Step 1.1: First read in the surface coordinate points and draw the blade basin and back contour lines PF1 and PF2 for the first time; According to the format requirements of the modeling software, the surface coordinate point data file is prepared and read in to form the blade basin and back contour lines PF1 and PF2; Step 1.2: Construct the intake and exhaust edge fillets C1 and C2; Construct the inlet and exhaust edge fillets C1 and C2 according to the center position coordinates and radius values ​​provided in the design drawings; Step 1.2: Create a tangent line through two inverted circles and construct a tangent point; Take the coordinate point of the fillet C1 and C2 near the intake and exhaust edges as a point through which the tangent passes, and make tangent lines L1, L2, L3, and L4 of circles C1 and C2, forming tangent points P201, P202, P203, and P204; Step 1.3: Construct the leaf basin and leaf back cross-section lines PF1 and PF2; Construct the blade basin profile line PF1: starting from one of the tangent points P201, connecting to the other tangent point P202 through the design coordinate point and ending; Construct the leaf back profile line PF2: starting from one of the tangent points P203, connecting to another tangent point P204 through the design coordinate point and ending; Step 1.4 Construct the tangent fillet profiles PF3 and PF4 By designing the coordinates P51, P52, .....P95, P96, and ending at the tangent point P202, the tangent fillet contours PF3 and PF4 are constructed. Step 1.5 Connect the four profiles to construct the complete theoretical section PF5 As shown, select PF1, PF2, PF3, and PF4 in sequence to construct the theoretical cross-sectional profile PF5; Step 2: Extend along the contour direction and create a new fillet on the intake edge: Step 2.1 Construct the midline L5 of the two tangent lines Select the inlet edge fillet and the nearest edge point to construct two tangent lines L1 and L3, and construct the midline L5 of the two tangent lines Step 2.2: Determine the extension direction of the two mid-line as the conformal direction; The conforming direction is defined in the program: the conforming direction of the air inlet edge is the extension direction of the straight line L5; Step 2.3: Assign the extension distance a value of #L11 in the model building program, with an initial value of 0.05 to 0.

1. Assign the X-axis and Y-axis coordinate values ​​of the center of the newly created intake edge fillet C3. The center coordinate offset value is (#XA1, #YA1). The offset value is the product of the cosine function value and the sine function value of the angle between the extended distance and the straight line L5, that is: #XA1=#L11*COS(#A1), the extended value of the X-axis is the angle between #L11 and line L5 The product of the cosine function values ​​of degree A1; #YA1=#L11*SIN(#A1), the Y-axis extension value is the angle between #L11 and line L5 The product of the values ​​of the long sine function of degree A1; P135, C3, the center of the intake side fillet C3 is defined as point P135 P136, P135, TR, IX#XA1, IY#YA1, the coordinate value of point P136 is the displacement of point P135 (#XA1, #YA1); Step 2.4 Create a new intake edge fillet C3 With the newly created intake edge circle center point as the circle center, construct the intake edge fillet C3 with the theoretical radius of the design drawing; Step 3: Extend along the contour direction and create a fillet on the exhaust edge: Follow the same steps as step 2 to construct the intake edge fillet C4 with the theoretical radius of the design drawing; Step 4: Use the newly created fillet to construct the intake and exhaust fillet contours to complete the construction of the new section; Step 4.1 Establish tangent lines to the newly constructed intake and exhaust edge fillets C3 and C4, and find the new tangent points P205, P206, P207, and P208 Select the inlet edge fillet and the nearest edge point at the basin and back section data points to construct four tangent lines L5, L6, L7, and L8 to form new tangent points P205, P206, P207, and P208 Step 4.2 Construct the new leaf basin and leaf back profile lines With the newly constructed tangent points P205, P206, P207, and P208 as the starting and ending points, the profile lines PF6 and PF7 of the leaf basin and leaf back are constructed. Step 4.3 Construct new intake and exhaust edge contours Construct the intake and exhaust edge contour lines PF8 and PF9 through the new tangent points. Step 4.4 Construct a new section line Select the newly constructed blade basin (blade back) profile line and intake (exhaust) edge contour line in turn and connect them to form a new complete profile PF10.

Images