A method for generating spraying trajectories on aero-engine turbine blades

Abstract

This invention belongs to the field of high-end manufacturing technology and relates to a method for generating spraying trajectories for aero-engine turbine blades. The method includes: Step 1, constructing a 3D model of a complex curved surface blade of an aero-engine; Step 2, based on the spraying spacing obtained from a coating accumulation model, using a slicing algorithm to slice the complex curved surface blade model of the aero-engine to generate spraying paths; Step 3, based on the required blade height and optimized spraying spacing, using the number of layers where the tangent plane intersects with the aero-engine blade model, obtaining the number of spraying paths; Step 4, based on the optimized spraying spacing, spraying distance, and spraying power, inferring the speed to obtain the spraying speed of each path. This invention can effectively achieve uniform spraying of aero-engine blades, ensuring the uniformity of the spraying, and simultaneously ensuring the uniformity of heat input and the lifespan of the thermal barrier coating through speed control.

Description

Technical Field

[0001] This invention belongs to the field of high-end manufacturing technology and relates to a method for generating spraying trajectories on aero-engine turbine blades. Background Technology

[0002] As aero-engines continue to evolve towards higher performance and higher thrust-to-weight ratios, the operating environment of their core hot-end components is becoming increasingly demanding, with engine inlet gas temperatures continuously rising. As one of the key components in aero-engines that withstands high thermal and mechanical loads, turbine blades must endure high-temperature strength and oxidation during long-term service, placing extremely stringent requirements on the high-temperature strength and oxidation resistance of the turbine blade substrate material. To effectively improve the service life of turbine blades in high-temperature environments, thermal barrier coatings are widely used as an important surface protection technology. These coatings possess low thermal conductivity, high melting point, stable high-temperature phase structure, and good chemical stability, enabling them to form an effective thermal barrier on the turbine blade surface, significantly reducing the actual service temperature of the substrate material, thereby slowing down material performance degradation and improving reliability and safety.

[0003] In the actual application of thermal barrier coatings, traditional spraying processes face numerous technical challenges when the target material is a workpiece with complex curved surfaces, such as turbine blades. On one hand, complex three-dimensional curved surfaces lead to variations in the spraying distance and relative speed between the spray gun and the workpiece surface, resulting in uneven local heat input and inconsistent coating thickness distribution. On the other hand, compared to conventional spraying, the geometric complexity of turbine blades significantly increases the difficulty of the spraying trajectory, placing higher demands on the continuity of the spraying path. Therefore, optimized design of the spraying trajectory for complex curved turbine blades and precise control of the spraying heat input are crucial for improving the uniformity and stability of thermal barrier coatings. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art and to propose a method for generating the spraying trajectory of aero-engine turbine blades. The method aims to generate the spraying trajectory on the surface of the turbine blades and control the spraying speed to ensure the uniformity of the sprayed coating and heat input, thereby improving the quality of the coating.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for generating spraying trajectories for aero-engine turbine blades, comprising: Step 1: Construct a 3D model of a complex curved surface blade for an aero-engine; Step 2: Based on the coating accumulation model, the spraying spacing is obtained. The slicing algorithm is used to slice the complex curved surface blade model of the aero-engine. Based on each path point obtained from the slice, the strip-shaped average curvature characteristics of each region are obtained, and the spacing is optimized and adjusted. The path points are selected according to the optimized spacing. Step 3: Based on the required blade height and optimized spraying spacing, obtain the number of spraying paths by utilizing the number of layers where the tangential plane intersects with the aero-engine blade model. Step 4: Based on the optimized spraying spacing, spraying distance, and spraying power, the speed is calculated to obtain the spraying speed for each path.

[0006] Further, step one includes: drawing a complex curved surface blade model of an aero-engine in 3D software, converting it to STL format, and then processing the 3D point cloud to obtain the corresponding number of point clouds.

[0007] Furthermore, in step two, the coating accumulation model is an elliptic double-β model.

[0008] Furthermore, in step two, the optimization of the spray spacing and the generation of the spray path specifically include: Calculate the average curvature of each path point; The average principal curvature is obtained by using the principal curvature, Gaussian curvature, and normal rate of change of the plane path points and surrounding points. The path points are then optimized to obtain the optimized spraying spacing. The optimized path points are then interpolated to generate the spraying path.

[0009] Furthermore, in step four, the spraying speed for each path is calculated using the following formula: ; In the formula, It is the spraying speed on each path. It's the power of the spray gun. Where E is the distance between the spray gun and E is a constant representing the heat input per unit area. For optimized spray spacing.

[0010] This invention extracts point clouds from a constructed 3D model and slices them to obtain path points, enabling the generation of spraying path points on complex curved surfaces, thus ensuring the uniformity of the sprayed coating. Further optimization of the path points is achieved by determining an appropriate spraying spacing and based on the curvature of the surface, further improving the uniformity of the spraying. The speed of each spraying path is obtained by inversely calculating the speed using formulas based on the spray gun distance, spacing, and power, ensuring the uniformity of heat input across the entire blade surface. Through reasonable trajectory planning and speed adjustment, the uniformity of the coating is ultimately ensured, meeting the requirements of thermal barrier coatings for aero-engine turbine blades and extending blade life. In summary, the beneficial effects of this invention are that it effectively reduces the unevenness of traditional spraying and heat input, while lowering operating costs and improving coating quality. Attached Figure Description

[0011] Figure 1 This is a flowchart of the method for generating the spraying trajectory of an aero-engine blade in an embodiment of the present invention; Figure 2 This is a schematic diagram of a method for generating the spraying trajectory of an aero-engine blade in an embodiment of the present invention. Figure 3 The image shows a MATLAB simulation of the appropriate spacing of the coating accumulation model in the method for generating the spray trajectory of aero-engine blades in this embodiment of the invention. Figure 4 This is a path diagram of the method for generating the spraying trajectory of an aero-engine blade in an embodiment of the present invention. Detailed Implementation

[0012] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention. The embodiments based on the present invention are within the scope of protection of the present invention.

[0013] This invention provides a method for generating spraying trajectories on aero-engine turbine blades, the process of which is as follows: Figure 1 As shown, it includes: Step 1: 3D modeling of the aircraft engine to be coated.

[0014] After converting the drawn complex curved surface blade model of the aero-engine into STL format, 3D point cloud processing is performed to obtain an appropriate number of point clouds.

[0015] Step 2: Calculate the spraying spacing based on the coating accumulation model.

[0016] In this invention, the coating accumulation model adopts an elliptical double β model to obtain a suitable spraying spacing to achieve uniformity.

[0017] The calculation formula for the elliptic double-β model is as follows: ; in, , For the maximum coating thickness, and These are the major and minor semi-axis of the ellipse, respectively. and Using distributed parameters to control the attenuation rate of the coating thickness, a coating accumulation model is obtained: ; in, , ; This represents the time taken to travel along the y-axis in the elliptical model.

[0018] The final spray length and height are as follows: ; ; in, This refers to the spraying length; The spraying height is in the y-direction; This represents the speed at which the coating moves along the y-axis.

[0019] The final dynamic coating accumulation model formula is obtained as follows: .

[0020] This example uses the final dynamic coating accumulation model formula described above for MATLAB simulation. The parameters are not finalized and are for reference only. The simulation results are as follows: Figure 3 The coating simulation diagram shown is used to determine the spraying spacing.

[0021] In this invention, after obtaining a suitable spraying spacing based on the above model, a slicing algorithm is used to slice the complex curved surface blade model of an aero-engine. A schematic diagram of the slicing is shown below. Figure 2 As shown.

[0022] Based on each path point obtained from the slice, the average curvature characteristics of each region are calculated; and the spraying spacing is optimized and adjusted.

[0023] Specifically, after the paths on the horizontal slice are determined, the principal curvature, Gaussian curvature, and rate of change of normal are calculated for these path points and surrounding path points. The average curvature is then calculated to obtain path points superior to those in the first slice. Spacing optimization is then performed on each path, resulting in the following mathematical formula: ; In the formula, It is the first Path, The spraying spacing is obtained based on the planar elliptic double β model. The weights of the principal curvature term, The weights of the curvature gradient term, The weight of the normal rate of change term, For the first The average maximum principal curvature of the region corresponding to each path. For curvature gradient, For the first The average normal rate of change along the path.

[0024] Step 3: After optimizing and adjusting the spraying spacing as described above, based on the required height and spacing of the sprayed blades, such as... Figure 3As shown, the number of intersecting layers is determined by intersecting the tangent plane with the aero-engine blade model, and the number of spraying paths is obtained using the following formula; ; in, It refers to the location of each path. This is the initial path. It's the number of items. The path spacing is adjusted based on curvature.

[0025] Step 4: After determining the spraying spacing, the heat input E received per unit area is set as a constant, and the velocity of each diameter is calculated using the following formula:

[0026] In the formula, It is the speed on each path. It's the power of the spray gun. Where is the spray gun distance, and E is a constant representing the heat input. This represents the path spacing.

[0027] By determining the speed on each path as described above, the thermal uniformity of the spraying is ensured.

[0028] By using cubic spline interpolation to connect the path points, the path is smoothed, resulting in the final path as shown below. Figure 4 As shown in the figure, the red line represents the path points generated on the front surface, which are connected by interpolation, and the green line represents the path connected by interpolation on the back surface.

[0029] This invention can effectively achieve uniform coating on aero-engine blades, ensuring coating uniformity. Simultaneously, by controlling the spray speed, it ensures uniform heat input and extends the lifespan of the thermal barrier coating. The above describes a preferred embodiment of this invention.

Claims

1. A method of spray trajectory generation for a turbine blade of an aeroengine, characterized in that, The application relates to an aero-engine complex curved surface blade spraying path optimization method. Step one, constructing a three-dimensional model of an aero-engine complex curved surface blade; Step two, based on the spraying interval obtained by a coating accumulation model, adopting a slice algorithm, slicing the aero-engine complex curved surface blade model, based on each path point obtained by slicing, obtaining the zonal average curvature feature of each region, optimizing and adjusting the interval, and generating a spraying path; Step three, according to the height of a required spraying blade and the optimized spraying interval, obtaining the number of spraying paths by using the number of layers intersected by a tangent plane and the aero-engine blade model; Step four, based on the optimized spraying interval, spraying distance and spraying power, the size of the speed is backstepped to obtain the spraying speed of each path.

2. The method of claim 1, wherein, Step one includes: drawing an aero-engine complex curved surface blade model in three-dimensional software, converting the model into an STL format, and then processing a three-dimensional point cloud to obtain the corresponding point cloud quantity.

3. The method of claim 1, wherein, In step two, the coating accumulation model is an elliptical double-beta model.

4. The method of claim 1, wherein, In step two, the optimization of the spraying interval and the generation of the spraying path specifically include: Obtaining the average curvature of each path point; Based on the principal curvature, the Gaussian curvature and the normal variation rate of the plane path point and the surrounding points, the average principal curvature is obtained, the path point is optimized and selected, the optimized spraying interval is obtained, the interpolation processing is conducted on the optimized and selected path point, and the spraying path is generated.

5. The method of claim 1, wherein, In step four, the spraying speed of each path is calculated by using the following formula: ； wherein is the spray speed on each path, is the power of the spray gun, is the spray gun distance, E is a constant for heat input, representing the heat input received per area; is the optimized spacing.

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