A method for correcting throat area measurement error

Abstract

A method for correcting throat area measurement errors includes the following steps: mounting a turbine guide vane on the turntable of a coordinate measuring machine; setting at least two radial measuring points in one or more throat windows of the turbine guide vane, the radial measuring points being set on the guide vane rim plate; obtaining a first set of measuring points, the first set of measuring points being the coordinate set of the radial measuring points; rotating the turntable by a division angle; obtaining a second set of measuring points, the second set of measuring points being the coordinate set of the radial measuring points after rotation; obtaining correction parameters based on the first set of measuring points and the second set of measuring points, and correcting the measurement coordinate system.

Description

Technical Field

[0001] This invention relates to engine assembly, and more specifically to a method for correcting errors in throat area measurement. Background Technology

[0002] The minimum exhaust edge area in the converging channel of the guide vane is called the guide vane throat area, and its size directly affects engine performance. Practice has shown that variations in the throat area of ​​the high-pressure turbine first-stage guide vane and the low-pressure turbine first-stage guide vane affect engine high-pressure speed, thrust, Mach 2 performance, T4 temperature, and fuel consumption. Therefore, the throat area of ​​engine blades is a crucial parameter for engine assembly and tuning, and its measurement is key to blade assembly. The blade channel is a spatial curved surface channel formed by the upper and lower edge plates of the blade and the airfoil profiles between each pair of blades. The designed throat area measuring instrument can accurately detect the channel width dimension of a specified cross-section between each channel window and the channel height dimension of the upper and lower edge plates, thereby calculating the blade throat area. The flow rate of the throat area is related to the engine thrust, and obtaining the uniformity of exhaust volume in the blade channel through the throat area measuring instrument is crucial for engine performance analysis.

[0003] Currently, the common method for measuring throat area is to use a coordinate measuring machine (CMM). The measurement process involves placing a turntable on the CMM, then placing the turbine casing unit with the guide assembly on the turntable, and performing centering, that is, aligning the center of the guide with the center of the turntable. Then, the CMM is used to measure the area of ​​the first window. After the measurement is completed, the turntable is controlled to move by one division angle phase, and then the area of ​​the next window is measured.

[0004] However, in actual measurement, there are still errors in the measurement results of the guide throat area. Therefore, there is an urgent need to provide a measurement method that can correct the guide throat area. Summary of the Invention

[0005] The purpose of this invention is to provide a method for correcting the measurement error of the throat area, which is used to correct the measurement error of the throat area of ​​a turbine guide vane in order to reduce the test error.

[0006] The above-mentioned method for correcting the throat area measurement error includes the following steps: mounting the turbine guide vane on the turntable of a coordinate measuring machine; setting at least two radial measuring points in one or more throat windows of the turbine guide vane, the radial measuring points being set on the guide vane rim plate; obtaining a first set of measuring points, the first set of measuring points being the coordinate set of the radial measuring points; rotating the turntable by a division angle; obtaining a second set of measuring points, the second set of measuring points being the coordinate set of the radial measuring points after rotation; obtaining correction parameters based on the first set of measuring points and the second set of measuring points, and correcting the measurement coordinate system.

[0007] In one or more embodiments, the turntable rotates in the yz plane of the measurement coordinate system, and the first set of measuring points is {(Pi xj Pi yj Pi zj The second set of measurement points is {(Qi)}, xj Qi yj Qi zj The correction parameter is obtained by the following formula:

[0008]

[0009] Where i represents the i-th throat window, j represents the j-th radial measuring point in the throat window, n represents the number of measuring points in the throat window, dθ represents the graduation angle, dy represents the correction component of the measurement coordinate system along the y-axis, and dz represents the correction component of the measurement coordinate system along the z-axis.

[0010] In one or more embodiments, the radial measuring point is provided in each of the throat windows.

[0011] In one or more embodiments, at least two radial measuring points are provided in each of the throat windows.

[0012] In one or more embodiments, in each of the throat windows, the radial measuring points are evenly distributed on the guide vane edge plate.

[0013] In one or more embodiments, the guide vane edge plate is the upper edge plate or the lower edge plate of the turbine guide.

[0014] In one or more embodiments, during the process of obtaining the first set of measuring points, the turbine guide and the turntable remain fixed in the coordinate measuring machine.

[0015] The above-mentioned method for correcting throat area measurement errors adjusts and corrects the measurement coordinate system before formally measuring the throat area. Based on the eccentricity of the guide rotation axis relative to the turntable rotation axis obtained from multiple radial measuring points set on the guide, the eccentricity correction of the measurement coordinate system is completed, so that the corrected measurement coordinate system coincides with the coordinate system established for throat area measurement. Thus, in the formal throat area measurement test, the measurement error caused by the eccentricity between the guide rotation axis and the turntable rotation axis can be avoided, improving the test accuracy of the three-coordinate throat area measurement. Attached Figure Description

[0016] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0017] Figure 1 This is a schematic diagram of throat area detection according to one embodiment.

[0018] Figure 2 This is a flowchart of a method for correcting errors in throat area measurement.

[0019] Figure 3 This is a schematic diagram of the radial measuring point location according to one embodiment.

[0020] Symbol marking explanation

[0021] 1 Turntable

[0022] 2. Turbine guide

[0023] 3 Coordinate Measuring Instrument

[0024] 4 Radial measuring points

[0025] 5 areas

[0026] 11. Rotation axis of the turntable

[0027] 21. Guide axis of rotation Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description to provide a full understanding of the invention. However, the invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual applications without departing from the spirit of the invention. Therefore, the scope of protection of the invention should not be limited by the content of these specific embodiments. It should be noted that these and subsequent accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the actual scope of protection claimed by the invention.

[0029] like Figure 1 As shown, the throat area of ​​the turbine guide vane 2 is measured using a coordinate measuring machine 3. The airflow channel formed between adjacent guide vanes of the turbine guide vane 2 is the throat window. The throat area refers to the minimum interface area formed by each pair of adjacent blades of the exhaust guide vane and the upper and lower edge plates forming a relatively independent airflow channel.

[0030] In traditional measurement processes, the turbine guide 2 is mounted on the turntable 1 of the coordinate measuring machine 3 and centered. When measuring the area of ​​one throat window, the turntable 1 needs to be rotated before measuring the area of ​​the next throat window. Since only coarse centering has been performed between the guide's rotation axis 21 and the turntable's rotation axis 11, there is still an eccentricity between them. (Refer to...) Figure 3There is an eccentricity between the intersection of the y-axis and z-axis of the coordinate system established with the guide rotation axis 21 as the x-axis and the intersection of the y'-axis and z'-axis of the coordinate system established with the turntable rotation axis 11 as the x'-axis. Therefore, when the turntable 1 rotates around its own rotation axis 11 by one division angle, the actual rotation axis 21 of the guide is eccentric to the turntable's own axis 11. If the turntable's own rotation axis 11 is used as the reference for measurement, it will affect the throat area measurement result.

[0031] like Figure 2 As shown, one or more embodiments disclosed below provide a method for correcting throat area measurement errors, including the following steps: S1 assembling a turntable 1 and a guide 2; S2 setting radial measuring points 4; S3 obtaining a first set of measuring points; S4 rotating the turntable; S5 obtaining a second set of measuring points; S6 obtaining correction parameters and performing correction. This method adjusts and corrects the measurement coordinate system before formally measuring the throat area. Correction parameters are obtained based on the coordinate positions of the radial measuring points 4 on the guide 2 before and after rotation. These correction parameters are used to correct the measurement coordinate system, ensuring that the corrected measurement coordinate system coincides with the coordinate system established for throat area measurement. Therefore, in the formal throat area measurement test, when the turntable 1 rotates by one division angle, the turbine guide 2 also rotates by one division angle. The throat area measured using the corrected measurement coordinate system can avoid measurement errors caused by the eccentricity between the guide rotation axis 21 and the turntable rotation axis 11.

[0032] The specific steps are as follows:

[0033] Step S1: Assemble the turntable 1 and guide 2. Install the turbine casing with turbine guide 2 on the turntable 1 of the coordinate measuring machine 3. Align the turbine guide 2 so that the center of the turbine guide 2 is aligned with the center of the turntable 1. In the assembled state, there is an eccentricity between the measurement coordinate system and the coordinate system established by the throat area measurement.

[0034] Among them, the measurement coordinate system refers to the coordinate system established with turntable 1 as the reference. This coordinate system is established with the rotation axis 11 of the turntable as the x-axis, and it is also the coordinate system of the coordinate measuring machine 1 itself. The coordinate system established for throat area measurement refers to the coordinate system established with turbine guide 2 as the reference. This coordinate system is established with the rotation axis 21 of the guide 2 as the x-axis. In the process of throat area measurement, this coordinate system must be used as a reference for measurement.

[0035] In one embodiment, the measurement coordinate system can be a coordinate system with the turntable rotation axis 11 as the x-axis and the upper surface of the turntable 1 as the yz plane, and the coordinate system for throat area measurement is a coordinate system with the guide rotation axis 21 as the x-axis and the upper surface of the guide 2 as the yz plane.

[0036] Step S2: Set radial measuring point 4. Figure 3 This is a top view of the turbine guide vane 2. Area 5 in the figure represents the region where one of the throat windows is located. Two or more radial measuring points 4 are provided in at least one throat window of the turbine guide vane 2. The radial measuring points 4 are located on the guide vane rim plate. In one embodiment, the guide vane rim plate is the upper rim plate of the turbine guide vane 2; in other embodiments, it can also be the lower rim plate of the turbine guide vane 2. It is understood that the two or more radial measuring points 4 are either simultaneously located on the upper rim plate of the turbine guide vane 2 or simultaneously located on the lower rim plate of the turbine guide vane 2, but not simultaneously located on both the upper and lower rim plates of the turbine guide vane 2.

[0037] Then, steps S3 to S5 are executed. Step S3: Obtain the first set of measurement points {(Pi xj Pi yj Pi zj The first set of measuring points is the set of coordinates of the radial measuring points 4 selected in step S2, denoted by Pi. xj For example, Pi xj This represents the x-coordinate value of the j-th radial measuring point 4 in the i-th throat window. The coordinate position of the radial measuring point 4 can be measured by the coordinate measuring machine 1; Step S4: Rotate the turntable 1, specifically, rotate the turntable 1 by a division angle, and rotate the turntable 1 in the yz plane of the measurement coordinate system; Step S5: Obtain the second set of measuring points {(Qi xj Qi yj Qi zj The second set of measuring points is the set of coordinates of radial measuring point 4 after it rotates around the rotation axis 11 of turntable 1.

[0038] Step S6: Obtain the correction parameters and perform correction. Based on the first set of measurement points {(Pi xj Pi yj Pi zj )} and the second set of measurement points {(Qi xj Qi yj Qi zj The correction parameters are obtained using the following formula:

[0039]

[0040] Where i represents the i-th throat window of the radial measuring point 4 in the turbine guide 2, j represents the j-th radial measuring point in the throat window, n represents the number of measuring points in the throat window, dθ represents the indexing angle of the turntable 1, dy represents the correction component of the measurement coordinate system along the y-axis, and dz represents the correction component of the measurement coordinate system along the z-axis.

[0041] Subsequently, the measurement coordinate system can be corrected using dy and dz. By moving the measurement coordinate system along its y-axis by dy and along its z-axis by dz, the eccentricity correction of the measurement coordinate system can be completed. In the formal throat area measurement test, the key measuring points of the turbine guide 2 are measured using the corrected measurement coordinate system. This avoids the measurement error caused by the eccentricity between the guide rotation axis 21 and the turntable rotation axis 11. The key measuring points refer to the multiple measuring points specified in the test design that need to be measured during the throat area measurement. Substituting the coordinate positions of these multiple measuring points into the throat area calculation formula yields the throat area of ​​the guide 2.

[0042] like Figure 3 As shown, in one embodiment, the turbine guide vane 2 has 12 throat windows, and two radial measuring points 4 are evenly distributed on the guide vane edge plate in each throat window. As shown in the figure, the two radial measuring points 4 in each throat window are symmetrically positioned. During the measurement process, 24 radial measuring points 4 need to be measured. By measuring the coordinates of multiple radial measuring points 4 before and after rotation, multiple correction parameters are calculated. Taking the average of these multiple correction parameters can effectively reduce experimental errors. In another embodiment, more than two radial measuring points 4 can be set in each throat window.

[0043] Furthermore, in one embodiment, during the process of obtaining the first set of measuring points, the turbine guide and the turntable remain fixed in the coordinate measuring machine, that is, the turntable does not rotate during the process of obtaining the first set of measuring points.

[0044] The above-mentioned method for correcting the throat area measurement error uses the radial measuring point 4 set on the turbine guide 2 assembly to obtain the eccentricity of the guide rotation axis 21 relative to the turntable rotation axis 11, thereby completing the eccentricity correction of the measurement coordinate system and also correcting the throat area measurement result. This improves the test accuracy of the three-coordinate throat area measurement, thereby improving the engine inspection quality and the engine first-time assembly pass rate.

[0045] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A method of correcting for throat area measurement errors, characterized by, Includes the following steps: Mount the turbine guide on the turntable of the coordinate measuring machine; At least two radial measuring points are provided in one or more throat windows of the turbine guide vane, and the radial measuring points are located on the guide vane rim plate; Obtain a first set of measuring points, wherein the first set of measuring points is the coordinate set of the radial measuring points; Rotate the turntable by one division angle; Obtain a second set of measuring points, which is the coordinate set of the radial measuring points after rotation; Correction parameters are obtained based on the first set of measuring points and the second set of measuring points, and the measurement coordinate system is corrected accordingly. The rotary table rotates in a yz plane of the measurement coordinate system, the first set of measurement points is , the second set of measurement points is , and the correction parameter is obtained by the following formula: ， Where i represents the i-th throat window, j represents the j-th radial measuring point in the throat window, n represents the number of measuring points in the throat window, dθ represents the graduation angle, dy represents the correction component of the measurement coordinate system along the y-axis, and dz represents the correction component of the measurement coordinate system along the z-axis. At least two radial measuring points are provided in each throat window, and two or more radial measuring points are simultaneously provided on the upper edge plate of the turbine guide or simultaneously provided on the lower edge plate of the turbine guide.

2. The method for correcting errors in throat area measurement as described in claim 1, characterized in that, During the process of obtaining the first set of measuring points, the turbine guide and the turntable remain fixed in the coordinate measuring machine.

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