Processing method of super-large Francis turbine blade physical model

Abstract

The present application belongs to the technical field of processing of casting wood mould, and particularly relates to a processing method of a super-large mixed-flow water turbine blade physical model. The three-dimensional numerical model is placed according to the front view orthographic projection, a stepped decomposition line L2 passing through B point is made along the z-axis direction, and the stepped decomposition line L2 is staggered along the x-axis direction in two sections; the three-dimensional numerical model is simulated to be cut along the stepped decomposition line L2 to form a simulated flat piece and a simulated warped piece; C point is lifted by rotating the simulated flat piece, so that the intersection C is equal in height to the highest point of the upper surface of the simulated flat piece; E point is lifted by rotating the simulated warped piece twice, and finally D point is lower than E point; when the simulated flat piece and the simulated warped piece are within the processing range of the numerical control milling machine, the three-dimensional numerical model is cut according to the stepped decomposition line L2 to form the flat piece and the warped piece, and then the numerical control milling machine is used for processing respectively. The physical model of the super-large mixed-flow water turbine blade can be conveniently processed by the numerical control milling machine.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of processing of casting wooden patterns, and particularly relates to a processing method of a super-large mixed-flow water turbine blade physical model. BACKGROUND

[0002] A water turbine is a power machine for converting the energy of water flow into rotating mechanical energy, and is mostly installed in a hydropower station to drive a generator to generate electricity. The larger the capacity of a unit is, the larger the size of the blade of the water turbine is. Generally, a water turbine unit with a runner diameter greater than or equal to 8 meters is a super-large water turbine unit. The units of a large hydropower station such as the Three Gorges, Baihetan, Xiangjiaba and Wuqiaoxi, which are of the order of megawatt, are super-large mixed-flow water turbine units, and the blades of the water turbines are super-large mixed-flow water turbine blades. The length of a super-large mixed-flow water turbine blade is greater than or equal to 5 meters, the width is greater than or equal to 4 meters, and the height is greater than or equal to 2 meters.

[0003] A super-large mixed-flow water turbine blade is generally made of stainless steel by casting, and the most critical link of the casting of the super-large mixed-flow blade is the production and manufacturing of the physical model. The physical model of the super-large mixed-flow blade is usually made of wood, and the main processing mode is numerical control processing. Since the processing stroke of a woodworking numerical control milling machine, i.e., a three-axis numerical control milling machine, is limited, it is difficult to process the physical model of the super-large mixed-flow blade by using the numerical control milling machine, and therefore a manual processing mode is usually used. However, the manual processing mode has the disadvantages of low efficiency, poor precision and poor consistency. SUMMARY

[0004] The technical problem to be solved by the application is to provide a processing method of a super-large mixed-flow water turbine blade physical model, so as to facilitate the processing of the physical model of the super-large mixed-flow water turbine blade by using a numerical control milling machine.

[0005] The technical solution adopted by the application to solve the technical problem is as follows: the processing method of the super-large mixed-flow water turbine blade physical model comprises the following steps:

[0006] S1, placing a three-dimensional numerical model of a super-large mixed-flow water turbine blade physical model according to a front view orthographic projection, taking the lowest intersection A of the upper crown edge and the water outlet edge as a horizontal reference line L1, and the horizontal reference line L1 and the three-dimensional numerical model having an intersection point B; taking the original coordinates of the three-dimensional numerical model as a reference, making a stepped decomposition line L2 passing through the point B along the z-axis direction, and the stepped decomposition line L2 is offset along the x-axis direction in two sections; simulating cutting the three-dimensional numerical model along the stepped decomposition line L2 to form a simulated flat piece and a simulated warped piece;

[0007] Place the simulation flat slice according to the front view orthographic projection, draw the tangent line L3 of the highest intersection point C of the stepwise decomposition line L2 on the simulation flat slice and the water outlet edge, measure the included angle α between the tangent line L3 and the z-axis, rotate the simulation flat slice by the angle α counterclockwise with the x-axis as the rotation center, so that the intersection point C is at the same height as the highest point on the upper surface of the simulation flat slice; reduce the overall drop value of the simulation flat slice in the processing state, and determine whether the simulation flat slice is within the processing range of the numerical control milling machine;

[0008] Place the simulation warped slice according to the front view orthographic projection, D point is the highest intersection point of the lower ring edge and the water outlet edge, E point is the highest intersection point of the stepwise decomposition line L2 and the water inlet edge, D point is higher than E point, draw the line L4 connecting D point and E point, measure the included angle β between the line L4 and the z-axis, β>α; rotate the simulation warped slice by the angle γ counterclockwise with the x-axis as the rotation center, γ=α, to reduce the height difference between D point and E point; draw the line L5 connecting D point and the original coordinate origin O of the three-dimensional model, measure the included angle δ between the line L5 and the x-axis, rotate the simulation warped slice by the angle δ counterclockwise with the z-axis as the rotation center, so that D point is lower than E point; reduce the overall drop value of the simulation warped slice in the processing state, and determine whether the simulation warped slice is within the processing range of the numerical control milling machine;

[0009] When both the simulation flat slice and the simulation warped slice are within the processing range of the numerical control milling machine, cut the three-dimensional model according to the stepwise decomposition line L2 to form the flat slice and the warped slice; when the simulation flat slice and / or the simulation warped slice are not within the processing range of the numerical control milling machine, adjust the position of the stepwise decomposition line L2 along the direction of the x-axis until both the simulation flat slice and the simulation warped slice are within the processing range of the numerical control milling machine, and then cut the three-dimensional model according to the adjusted stepwise decomposition line L2 to form the flat slice and the warped slice;

[0010] S2, rotate the flat slice based on the original coordinates of the three-dimensional model, so that the flat slice is processed within the processing range of the numerical control milling machine; rotate the warped slice based on the original coordinates of the three-dimensional model, so that the warped slice is processed within the processing range of the numerical control milling machine;

[0011] S3, set up the mold membrane, so that the upper surface of the mold membrane is consistent with the inner side surface of the final shaped blade, place the processed flat slice and the processed warped slice on the mold membrane according to their respective positions, butt joint through the stepwise decomposition line L2, and assemble and fix the structure to connect the processed flat slice and the processed warped slice into a physical model.

[0012] Further, the mold membrane in step S3 comprises a bottom plate and a plurality of support plates vertically arranged on the bottom plate; the length direction of the support plates is parallel to the direction from the lower ring edge to the upper crown edge; the support plates are arranged in pairs along the direction from the water inlet edge to the water outlet edge; and the upper surface of the support plates serves as the upper surface of the mold membrane.

[0013] The fixing structure in the step S3 comprises an upper connecting rib, a lower connecting rib and a bolt; the upper connecting rib, the physical model and the lower connecting rib are connected through the bolt; the upper connecting rib is arranged on the outer side of the physical model, one end of the upper connecting rib is located on the machined flat piece, and the other end is located on the machined warped piece; the lower connecting rib is arranged on the inner side of the physical model and between the adjacent two supporting plates; one end of the lower connecting rib is located on the machined flat piece, and the other end is located on the machined warped piece; the fixing structure is provided with multiple groups, and the multiple groups of fixing structures are arranged in pairs and spaced apart along the direction from the water inlet edge to the water outlet edge.

[0014] Further, in the step S3, the supporting plate and the machined flat piece are positioned through the first groove and block structure, and the supporting plate and the machined warped piece are positioned through the second groove and block structure.

[0015] Further, the vertical connecting plate is further arranged, and the adjacent two supporting plates are connected through the connecting plate; the top end of the connecting plate is lower than the top end of the supporting plate; the connecting plate is provided with multiple blocks, and the multiple blocks of connecting plates are arranged in pairs and spaced apart along the length direction of the supporting plate; and the lower connecting rib is arranged on at least two blocks of connecting plates.

[0016] Further, the upper surface of each supporting plate is provided with a positioning line corresponding to the stepped decomposition line L2.

[0017] Further, in the step S1, when the position of the stepped decomposition line L2 is adjusted along the direction of the x-axis, the adjustment is performed according to the multiple of 25 mm.

[0018] Further, the fetal membrane in the step S3 is a wooden product.

[0019] Compared with the prior art, the method has the advantages that: the method provided by the application is used for processing the physical model of the super-large mixed flow type water turbine blade, and the super-large water turbine blade can be processed through the numerical control milling machine. The method solves the problem that the physical model of the super-large mixed flow type water turbine blade cannot be processed through the numerical control milling machine, and reduces the difficulty of numerical control processing. The method has the advantages of simple operation, high precision, high efficiency, good consistency and the like. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic view of the horizontal reference line L1 which is the lowest intersection point A of the upper edge and the water outlet edge, and the horizontal reference line L1 intersects with the three-dimensional model at the point B;

[0021] Figure 2 is a position schematic view of the stepped decomposition line L2;

[0022] Figure 3 is a schematic view of the tangent line L3 which passes through the stepped decomposition line L2 and the highest intersection point C of the simulated flat piece upper surface and the water outlet edge.

[0023] Figure 4 This is a schematic diagram showing how the simulated flat plate is rotated counterclockwise by an angle α with the x-axis as the center of rotation, so that the intersection point C is at the same height as the highest point of the upper surface of the simulated flat plate.

[0024] Figure 5 This is a schematic diagram of line L4 connecting points D and E of the simulated warped plate;

[0025] Figure 6 This is a schematic diagram of rotating the simulated warped plate counterclockwise by an angle γ with the x-axis as the center of rotation;

[0026] Figure 7 This is a schematic diagram of the line L5 connecting point D and the original coordinate origin O of the 3D digital model;

[0027] Figure 8 This is a schematic diagram of rotating the simulated warped plate counterclockwise by an angle δ with the z-axis as the center of rotation;

[0028] Figure 9 This is a schematic diagram of the three-dimensional structure of the fetal membranes;

[0029] Figure 10 It is a three-dimensional schematic diagram of the processed flat sheet and the processed warped sheet placed on the fetal membrane and connected by a fixing structure (the lower connecting rib is not shown);

[0030] Figure reference numerals: 1-Upper crown edge; 2-Lower ring edge; 3-Inlet edge; 4-Outlet edge; 5-Simulated flat plate; 6-Simulated warped plate; 7-Fetal membrane; 701-Base plate; 702-Support plate; 703-Connecting plate; 704-Reinforcing plate; 8-Upper connecting rib; 9-Processed flat plate; 10-Processed warped plate. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] The fabrication method for a physical model of an ultra-large mixed-flow turbine blade includes the following steps:

[0033] S1, as Figure 1 , 2 As shown, the three-dimensional digital model of the physical model of the ultra-large mixed-flow turbine blade is placed according to the orthographic projection of the front view. The lowest intersection point A of the upper crown edge 1 and the outlet edge 4 is used as the horizontal reference line L1. The horizontal reference line L1 intersects with the three-dimensional digital model at point B. Based on the original coordinates of the three-dimensional digital model, a stepped decomposition line L2 passing through point B is drawn along the z-axis. The stepped decomposition line L2 is divided into two segments and offset along the x-axis. The three-dimensional digital model is simulated and cut along the stepped decomposition line L2 to form simulated smooth plate 5 and simulated warped plate 6.

[0034] like Figure 3、 4 As shown in FIG. 5, 6 and 7, the simulated flat piece 5 is placed in the orthographic projection of the front view, a tangent line L3 of the highest intersection C of the stepped decomposition line L2 on the upper surface of the simulated flat piece 5 and the water outlet edge 4 is drawn, the included angle a between the tangent line L3 and the z-axis is measured, a = 18°, the simulated flat piece 5 is rotated counterclockwise by the angle a with the x-axis as the rotation center, so that the intersection C is at the same height as the highest point of the upper surface of the simulated flat piece 5; the overall drop value of the simulated flat piece 5 in the processing state is reduced, and it is determined whether the simulated flat piece 5 is within the processing range of the numerical control milling machine. Specifically, the C point is lifted by rotating the simulated flat piece 5, so that the intersection C is at the same height as the highest point of the upper surface of the simulated flat piece 5. The overall drop value of the simulated flat piece 5 in the processing state is reduced, specifically, the distance between the highest point and the lowest point of the simulated flat piece 5 in the processing state is reduced. The simulated flat piece 5 is adjusted to be within the processing range of the numerical control milling machine, thereby reducing the difficulty of numerical control processing.

[0035] As shown in FIG. 5, 6 and 7, Figure 5 、 6 As shown in FIG. 5, 6 and 7, the simulated flat piece 5 is placed in the orthographic projection of the front view, a tangent line L3 of the highest intersection C of the stepped decomposition line L2 on the upper surface of the simulated flat piece 5 and the water outlet edge 4 is drawn, the included angle a between the tangent line L3 and the z-axis is measured, a = 18°, the simulated flat piece 5 is rotated counterclockwise by the angle a with the x-axis as the rotation center, so that the intersection C is at the same height as the highest point of the upper surface of the simulated flat piece 5; the overall drop value of the simulated flat piece 5 in the processing state is reduced, and it is determined whether the simulated flat piece 5 is within the processing range of the numerical control milling machine. Specifically, the C point is lifted by rotating the simulated flat piece 5, so that the intersection C is at the same height as the highest point of the upper surface of the simulated flat piece 5. The overall drop value of the simulated flat piece 5 in the processing state is reduced, specifically, the distance between the highest point and the lowest point of the simulated flat piece 5 in the processing state is reduced. The simulated flat piece 5 is adjusted to be within the processing range of the numerical control milling machine, thereby reducing the difficulty of numerical control processing.

[0036] When the simulated flat piece 5 and the simulated warped piece 6 are both within the processing range of the numerical control milling machine, the three-dimensional model is cut according to the stepped decomposition line L2 to form the flat piece and the warped piece; when the simulated flat piece 5 and / or the simulated warped piece 6 are not within the processing range of the numerical control milling machine, that is, the amplitude of the adjusted drop value is not enough, the position of the stepped decomposition line L2 is adjusted along the direction of the x-axis until the simulated flat piece 5 and the simulated warped piece 6 are both within the processing range of the numerical control milling machine, and then the three-dimensional model is cut according to the adjusted stepped decomposition line L2 to form the flat piece and the warped piece.

[0037] The three-dimensional numerical model of the super large Francis turbine blade physical model is placed according to the front view orthographic projection, that is, the outer side faces upward and the inner side faces downward.

[0038] S2, rotating the flat piece according to the original coordinates of the three-dimensional numerical model, so that the flat piece is processed within the processing range of the numerical control milling machine; rotating the warped piece according to the original coordinates of the three-dimensional numerical model, so that the warped piece is processed within the processing range of the numerical control milling machine.

[0039] S3, erecting the tire membrane 7 so that the upper surface of the tire membrane 7 is consistent with the inner side of the finally shaped blade, placing the processed flat piece 9 and the processed warped piece 10 on the tire membrane 7 according to their respective positions, connecting through the stepped decomposition line L2, and assembling the fixing structure to connect the processed flat piece 9 and the processed warped piece 10 into a physical model. The purpose of erecting the tire membrane 7 is to stably place the processed flat piece 9 and the processed warped piece 10, so as to facilitate the connecting operation and ensure that the finally shaped physical model meets the requirements.

[0040] The finally connected and shaped physical model placed on the tire membrane 7 has the inner side facing downward and the outer side facing upward.

[0041] Specifically, as shown in Figure 9 The tire membrane 7 in step S3 includes a bottom plate 701 and a plurality of support plates 702 vertically arranged on the bottom plate 701. The length direction of the support plate 702 is parallel to the direction from the lower ring edge 2 to the upper crown edge 1. The support plates 702 are arranged in pairs along the direction from the water inlet edge 3 to the water outlet edge 4. The upper surface of the support plate 702 serves as the upper surface of the tire membrane 7.

[0042] Specifically, as shown in Figure 10 The fixing structure in step S3 includes an upper connecting rib 8, a lower connecting rib, and a bolt. The upper connecting rib 8, the physical model, and the lower connecting rib are connected through the bolt. The upper connecting rib 8 is arranged on the outer side of the physical model, one end of the upper connecting rib 8 is located on the processed flat piece 9, and the other end is located on the processed warped piece 10. The lower connecting rib is arranged on the inner side of the physical model and between the adjacent two support plates 702. One end of the lower connecting rib is located on the processed flat piece 9, and the other end is located on the processed warped piece 10. There are multiple groups of fixing structures, and the multiple groups of fixing structures are arranged in pairs along the direction from the water inlet edge 3 to the water outlet edge 4. The upper connecting rib 8 is closely attached to the outer side of the physical model, and the lower connecting rib is closely attached to the inner side of the physical model.

[0043] In the step S3, the supporting plate 702 is positioned with the processed flat piece 9 through the first recessed block structure, and the supporting plate 702 is positioned with the processed warped piece 10 through the second recessed block structure. By setting the first recessed block structure and the second recessed block structure, the processed flat piece 9 and the processed warped piece 10 are quickly placed in position.

[0044] In order to further improve the placement accuracy of the processed flat piece 9 and the processed warped piece 10, preferably, the upper surface of each of the supporting plates 702 is provided with a positioning line corresponding to the stepped decomposition line L2.

[0045] Preferably, it further comprises a vertically arranged connecting plate 703, and two adjacent supporting plates 702 are connected through the connecting plate 703; the top end of the connecting plate 703 is lower than the top end of the supporting plate 702; the connecting plate 703 is provided with a plurality of connecting plates 703, and the plurality of connecting plates 703 are arranged in pairs along the length direction of the supporting plate 702; and the lower connecting rib is placed on at least two connecting plates 703. Specifically, the connecting plate 703 is connected with the supporting plate 702 through wooden screws or iron nails. Not only can the structural stability and support strength of the tire membrane 7 be improved, but also the lower connecting rib can be stably placed.

[0046] As a further preferred, it further comprises a reinforcing plate 704, and a plurality of supporting plates 702 are connected through the reinforcing plate 704, and the two ends of the length direction of the supporting plate 702 are connected with the reinforcing plate 704.

[0047] Preferably, after the step S3, it further comprises a step S4 of detecting whether the assembly size of the processed flat piece 9 and the processed warped piece 10 is in place through a numerical control milling machine, so as to further ensure that the inner side surface of the physical model is tightly coincided with the upper surface of the tire membrane 7. The numerical control milling machine detection has the advantages of simple operation and high accuracy.

[0048] Preferably, in the step S1, when the position of the stepped decomposition line L2 is adjusted along the x-axis direction, the adjustment is performed in multiples of 25mm.

[0049] Preferably, the tire membrane 7 in the step S3 is a wooden product.

[0050] The embodiments of the specific implementation are the preferred embodiments of the present application, and are not limited to the protection scope of the present application. Any equivalent changes made on the structure, shape and principle of the present application should be covered in the protection scope of the present application.

Claims

1. A method for processing a full-scale model of a blade of a super-hydraulic Francis turbine, characterized in that, The method comprises the steps of: S1, placing a three-dimensional model of a super-large Francis turbine blade physical model according to the front view orthographic projection, taking the lowest intersection A of the upper crown edge (1) and the water outlet edge (4) as a horizontal reference line L1, the horizontal reference line L1 and the three-dimensional model have an intersection B point; taking the original coordinates of the three-dimensional model as a reference, making a stepped decomposition line L2 passing through the B point along the z-axis direction, the stepped decomposition line L2 is offset along the x-axis direction in two sections; simulating cutting the three-dimensional model along the stepped decomposition line L2 to form a simulated flat piece (5) and a simulated warped piece (6); placing the simulated flat piece (5) according to the front view orthographic projection, making a tangent line L3 of the highest intersection C of the upper surface of the simulated flat piece (5) and the water outlet edge (4) passing through the stepped decomposition line L2, measuring the included angle α between the tangent line L3 and the z-axis, rotating the simulated flat piece (5) counterclockwise by an angle α with the x-axis as the rotation center, so that the intersection C is at the same height as the highest point of the upper surface of the simulated flat piece (5); reducing the overall drop value of the simulated flat piece (5) in the processing state, and determining whether the simulated flat piece (5) is within the processing range of the numerical control milling machine; placing the simulated warped piece (6) according to the front view orthographic projection, D point is the highest intersection of the lower ring edge (2) and the water outlet edge (4), E point is the highest intersection of the stepped decomposition line L2 and the water inlet edge (3), D point is higher than E point, making a connecting line L4 of D point and E point, measuring the included angle β between the connecting line L4 and the z-axis, β>α; rotating the simulated warped piece (6) counterclockwise by an angle γ with the x-axis as the rotation center, γ=α, to reduce the height difference between D point and E point; making a connecting line L5 of D point and the original point O of the original coordinates of the three-dimensional model, measuring the included angle δ between the connecting line L5 and the x-axis, rotating the simulated warped piece (6) counterclockwise by an angle δ with the z-axis as the rotation center, so that D point is lower than E point; reducing the overall drop value of the simulated warped piece (6) in the processing state, and determining whether the simulated warped piece (6) is within the processing range of the numerical control milling machine; when the simulated flat piece (5) and the simulated warped piece (6) are both within the processing range of the numerical control milling machine, cutting the three-dimensional model according to the stepped decomposition line L2 to form a flat piece and a warped piece; when the simulated flat piece (5) and / or the simulated warped piece (6) are not within the processing range of the numerical control milling machine, adjusting the position of the stepped decomposition line L2 along the x-axis direction until the simulated flat piece (5) and the simulated warped piece (6) are both within the processing range of the numerical control milling machine, and then cutting the three-dimensional model according to the adjusted stepped decomposition line L2 to form a flat piece and a warped piece; S2, rotating the flat piece based on the original coordinates of the three-dimensional model, so that the flat piece is processed within the processing range of the numerical control milling machine; rotating the warped piece based on the original coordinates of the three-dimensional model, so that the warped piece is processed within the processing range of the numerical control milling machine; S3, erecting a tire membrane (7), making the upper surface of the tire membrane (7) consistent with the inner side of the final forming blade, placing the processed flat piece (9) and the processed warped piece (10) on the tire membrane (7) according to their respective positions, connecting through the stepped decomposition line L2, assembling a fixing structure to connect the processed flat piece (9) and the processed warped piece (10) into a physical model.

2. The method for processing the physical model of the ultra-large mixed-flow turbine blade as described in claim 1, characterized in that, The tire membrane (7) in the step S3 comprises a bottom plate (701) and a plurality of support plates (702) vertically arranged on the bottom plate (701); the length direction of the support plates (702) is parallel to the direction from the lower ring edge (2) to the upper crown edge (1); the support plates (702) are arranged in pairs along the direction from the water inlet edge (3) to the water outlet edge (4); and the upper surface of the support plates (702) serves as the upper surface of the tire membrane (7). The fixing structure in the step S3 comprises an upper connecting rib (8), a lower connecting rib and a bolt; the upper connecting rib (8), the physical model and the lower connecting rib are connected through the bolt; the upper connecting rib (8) is arranged on the outer side of the physical model, one end of the upper connecting rib (8) is located on the processed flat piece (9), and the other end is located on the processed warped piece (10); the lower connecting rib is arranged on the inner side of the physical model and between the adjacent two support plates (702); one end of the lower connecting rib is located on the processed flat piece (9), and the other end is located on the processed warped piece (10); and a plurality of fixing structures are arranged in pairs along the direction from the water inlet edge (3) to the water outlet edge (4).

3. The method of claim 2, wherein the method further comprises the step of: In the step S3, the support plate (702) and the processed flat piece (9) are positioned through a first groove and protrusion structure, and the support plate (702) and the processed warped piece (10) are positioned through a second groove and protrusion structure.

4. The method of claim 2, wherein the method further comprises the step of: The step further comprises a plurality of vertically arranged connecting plates (703), and the adjacent two support plates (702) are connected through the connecting plates (703); the top end of the connecting plate (703) is lower than the top end of the support plate (702); and a plurality of connecting plates (703) are arranged in pairs along the length direction of the support plate (702).

5. The method of claim 2, wherein the method further comprises the step of: The upper surface of each support plate (702) is provided with a positioning line corresponding to the stepped decomposition line L2.

6. The method of claim 1, wherein the method further comprises the step of: In the step S1, when adjusting the position of the stepped decomposition line L2 along the x-axis direction, the adjustment is performed in multiples of 25 mm.

7. The method of claim 1, wherein the method further comprises the step of: The tire membrane (7) in the step S3 is a wooden product.

Images