An evaluation control method for the assembly quality of an aeroengine rotor

Abstract

The application discloses an aero-engine rotor assembly quality evaluation control method and device, obtains the radial runout data group of each rotor part in the rotor assembly at both ends in the constraint state; determines the actual rotation center line of the corresponding rotor part according to the radial runout data group; gradually fits the actual rotation center line of each rotor part in the rotor assembly, and obtains the actual rotation center line of the rotor assembly; calculates the runout deviation of each rotor part and the actual rotation center line of the rotor assembly; determines the flatness of the rotor assembly according to the corresponding runout deviation of each rotor part; the application can improve the accuracy of the rotor part measurement data by measuring the runout data of the rotor part in the constraint state, and can obtain the actual rotation center line of the rotor assembly with higher accuracy by generating the actual rotation center line of each rotor part according to the runout data group and gradually fitting the rotation center lines of the rotor assembly, so that the assembly quality of the rotor assembly can be improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aero-engine rotor assembly, and particularly relates to an evaluation control method for aero-engine rotor assembly quality. BACKGROUND

[0002] The aero-engine rotor is an important component of the aero-engine, and the assembly quality thereof directly affects the working efficiency of the aero-engine. The aero-engine rotor includes multiple rotor parts, i.e., multiple rotor parts are assembled together. During the manufacturing process of the aero-engine rotor parts, there are deviation conditions such as geometric runout, eccentricity and tilt. If the rotor is improperly assembled or lacks balance, etc., the deviation will be multiplied. When the engine is working, the rotor and the connecting part bear huge inertial force, aerodynamic load, thermal load and vibration load, the whole rotor part appears to be deviated and tilted, and the whole machine vibration exceeds the standard. Therefore, the assembly quality of the aero-engine rotor system has a relatively significant influence on the engine vibration and performance.

[0003] At present, the specific indexes for evaluating and controlling the rotor assembly quality include rotor geometric runout, initial unbalance and residual unbalance. In China, before the rotor is assembled, four points on the rotor part are measured, i.e., two end face probes and two radial probes, which are respectively used for measuring two end faces and two radial cylindrical surfaces of the rotor part. After all the rotor parts of the rotor assembly are measured by the above method, the rotor parts at each level are optimized and matched, including rotor center deviation optimization and rotor end face high-low point phase optimization, and finally the best assembly result of the rotor parts is obtained. Moreover, at present, in China, the center line of the whole rotor assembly is mainly determined by the center line of the first level rotor part, i.e., the center line of the first level rotor part is determined as the center line of the whole rotor. When the second, third, …, n level rotor parts are installed, according to the measurement result of the single part and the determined center line, the center line deviation or end face deviation is optimized with the center line of the first level part (i.e., the center line of the rotor assembly) to ensure that the center line deviation or end face deviation is minimized. Figure 1 However, since the rotor parts have mutual matching constraint relationship in the assembly state, there is a large error influence on the assembly result when the measurement is only performed in the free state. Moreover, the existing rotor assembly method does not consider the actual center line position of each level disc, which leads to that the center line of each level disc is far away from the actual center line of the rotor, and the farther away from the journal position. The control of the rotor unbalance is to reduce the rotor unbalance caused by the unbalanced mass distribution by 180° misalignment of the high points of the adjacent discs, which will lead to that the assembled rotor is in a bow type, and the assembly result is not repeatable. Therefore, the evaluation indexes such as rotor geometric runout, initial unbalance and residual unbalance cannot completely evaluate the assembly quality of the rotor.

[0004] SUMMARY​

[0005] The object of the present application is to provide an aero-engine rotor assembly quality evaluation control method, which measures rotor parts in a constrained state and correlates each rotor part in a rotor assembly to improve the measurement accuracy of the rotor assembly quality.

[0006] The present application adopts the following technical solution: an aero-engine rotor assembly quality evaluation control method, comprising the following steps:

[0007] Obtaining a radial runout data set of each rotor part at both ends in a constrained state in a rotor assembly;

[0008] Determining the actual rotation center line of the corresponding rotor part according to the radial runout data set;

[0009] Fitting the actual rotation center line of each rotor part in the rotor assembly step by step to obtain the actual rotation center line of the rotor assembly;

[0010] Calculating the runout deviation of each rotor part from the actual rotation center line of the rotor assembly;

[0011] Selecting the maximum value in the runout deviation of each rotor part as the flatness of the rotor assembly.

[0012] Further, determining the actual rotation center line of the corresponding rotor part according to the radial runout data set comprises:

[0013] Respectively performing least squares circle fitting on the radial runout data set at both ends of the rotor part to obtain the cross-sectional center coordinate value corresponding to each radial runout data set;

[0014] Generating the actual rotation center line of the rotor part according to the two cross-sectional center coordinate values.

[0015] Further, respectively performing least squares fitting on the radial runout data set at both ends of the rotor part comprises:

[0016] Generating each measurement point coordinate value according to each measurement data in the radial runout data set and the corresponding measurement phase angle;

[0017] Generating a least squares fitting target function according to the measurement point coordinate value;

[0018] Solving the least squares fitting target function to obtain the cross-sectional center coordinate value.

[0019] Further, the least squares fitting target function is:

[0020]

[0021] Wherein, F' is the least squares fitting target function, (xi , y i ) is the coordinate value of the i-th measuring point, (x0, y0) is the coordinate value of the center of the section circle, R is the radius of the least square circle, A = -2x o , B = -2y o ,

[0022] Further, fitting the actual rotation center line of each rotor part in the rotor assembly step by step comprises:

[0023] fitting the actual rotation center line of the current rotor part with the actual rotation center line of a rotor part combination; wherein the rotor part combination is a rotor part combination that has been assembled before the current rotor part is assembled.

[0024] Further, fitting the actual rotation center line of the current rotor part with the actual rotation center line of the rotor part combination comprises:

[0025] selecting two first coordinate points on the actual rotation center line of the current rotor part;

[0026] selecting two second coordinate points on the actual rotation center line of the rotor part combination before the current rotor part;

[0027] generating the fitted actual rotation center line according to the two first coordinate points and the two second coordinate points.

[0028] Further, generating the fitted actual rotation center line according to the two first coordinate points and the two second coordinate points comprises:

[0029] According to the standard equation, we can get wherein k1, k2, k3, x0, y0, z0 are unknown constants;

[0030] Taking the partial derivatives of a, b, c, d and setting them all to zero, we get:

[0031]

[0032] wherein x i = x1, x2, x3, x4, y i = y1, y2, y3, y4, z i = z1, z2, z3, z4, the two first coordinate points are (x1, y1, z1) and (x2, y2, z2), and the two second coordinate points are (x3, y3, z3) and (x4, y4, z4).

[0033] Further, calculating the runout deviation of each rotor part from the actual rotation center line of the rotor assembly comprises:

[0034] The distance between the cross-section center of each rotor part and the actual rotation center line of the rotor assembly is calculated, and the distance is taken as the run-out deviation.

[0035] The application has the beneficial effect that the application can improve the accuracy of the measurement data of the rotor parts by measuring the run-out data of the rotor parts in the constrained state, and can improve the assembly quality of the rotor assembly by generating the actual rotation center line of each rotor part according to the run-out data group, fitting the actual rotation center lines, and obtaining the actual rotation center line of the rotor assembly with higher accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A measurement state diagram of the rotor parts in the free state in the prior art;

[0037] Figure 2 A timing rotation center line position diagram in the assembly process of the rotor assembly in the prior art;

[0038] Figure 3 A flowchart of an evaluation control method for the assembly quality of the aero-engine rotor in an embodiment of the application;

[0039] Figure 4 A structure diagram of the rotor parts in the constrained state during assembly in an embodiment of the application;

[0040] Figure 5 A fitting diagram of the actual rotation center line of the two-stage rotor assembly in an embodiment of the application;

[0041] Figure 6 A fitting diagram of the actual rotation center line of the three-stage rotor assembly in an embodiment of the application;

[0042] Figure 7 A two-dimensional simplified model diagram of the flatness in an embodiment of the application;

[0043] Figure 8 An effect verification diagram in an embodiment of the application. DETAILED DESCRIPTION

[0044] The application will be described in detail below in combination with the drawings and specific embodiments.

[0045] At present, the center line of the whole rotor assembly is mainly determined by the actual rotating center line of the first stage rotor part when the rotor assembly is assembled, that is, the actual rotating center line of the first stage rotor part is determined as the actual rotating center line of the whole rotor assembly. When other stage rotor parts are installed in the rotor assembly, the actual rotating center line of the first stage rotor part, that is, the actual rotating center line of the rotor assembly, is optimized according to the measurement results of the single rotor part and the determined actual rotating center line, so as to ensure that the actual rotating center line deviation or the end face deviation is minimum. Specifically, as shown in Figure 2 the actual rotating center line of the first stage rotor part is determined as the actual rotating center line of the rotor assembly, which is fixed and unchanged in the subsequent assembly process.

[0046] The existing rotor assembly method does not consider the position of the actual rotating center line of each stage rotor part, so that the actual rotating center line of each stage rotor part deviates from the actual rotating center line of the rotor assembly. The control method for the imbalance of the rotor assembly is generally to reduce the rotor imbalance caused by the imbalance of the mass distribution by 180° offset of the high points of adjacent rotor parts, which will cause the assembled rotor to be in a bow type, and the assembly result is not repeatable. Therefore, the assembly quality of the rotor cannot be completely evaluated by the evaluation indexes such as rotor geometric runout, initial imbalance and residual imbalance.

[0047] In view of the above problems, the present application provides an evaluation control method for the assembly quality of an aero-engine rotor, which can reduce the degree of "bow type" of the assembled rotor, improve the assembly performance of the rotor and maintain the stability during long-term work.

[0048] Specifically, the present application discloses an evaluation control method for the assembly quality of an aero-engine rotor, as shown in Figure 3 the method comprises the following steps: step S110, obtaining the radial runout data set of both ends of each stage rotor part in the rotor assembly in a constrained state; step S120, determining the actual rotating center line of the corresponding rotor part according to the radial runout data set; step S130, fitting the actual rotating center line of each stage rotor part in the rotor assembly step by step to obtain the actual rotating center line of the rotor assembly; step S140, calculating the runout deviation of each stage rotor part and the actual rotating center line of the rotor assembly; step S150, selecting the maximum value in the runout deviation corresponding to each stage rotor part as the flatness of the rotor assembly.

[0049] The present application can improve the accuracy of the rotor part measurement data by measuring the runout data of the rotor part in the constraint state, and then generating the actual rotation center line of each rotor part according to the runout data set, and fitting the plurality of actual rotation center lines to obtain the actual rotation center line of the rotor assembly with higher accuracy, thereby improving the assembly quality of the rotor assembly. The flatness evaluation method of the present application (i.e. the deviation degree of the rotor stage runout from the actual rotation center of the rotor) can further improve the assembly quality of the rotor.

[0050] Since the rotor parts have a matching constraint relationship with each other in the assembly state, there is a large error influence on the assembly result when measuring in the free state. Therefore, the present application proposes a method for measuring the parts in the "assembly constraint" state, i.e. using a pressing tool to press the parts to the constraint state, as shown in Figure 4 The two end faces and the two radial cylindrical faces of each stage rotor are measured by four measuring heads, and the lower end face and the lower cylindrical face are used as the reference. Then, the least square method is used to fit the upper and lower end faces to obtain the corresponding center points, and the connecting line of the two center points is the actual rotation center line of the stage rotor.

[0051] In step S120, the actual rotation center line of the corresponding rotor part is determined according to the radial runout data set, which includes:

[0052] The radial runout data sets of the two ends of the rotor part are respectively fitted by the least square circle to obtain the cross-sectional center coordinate values corresponding to each radial runout data set; and the actual rotation center line of the rotor part is generated according to the two cross-sectional center coordinate values.

[0053] In the embodiment of the present application, the radial runout data sets of the two ends of the rotor part are respectively fitted by the least square circle, which includes: generating the coordinate values of each measurement point according to each measurement data in the radial runout data set and the corresponding measurement phase angle; generating a least square fitting target function according to the coordinate values of the measurement points; and solving the least square fitting target function to obtain the cross-sectional center coordinate values.

[0054] Specifically, the radial runout data measured on the upper cylindrical surface is added by a basic radius r0 to obtain the radius r i at the i-th measurement point on the cylindrical circle, and then there is r i =T ri +r0, wherein T ri is the radial runout data of the i-th measurement point.

[0055] Then, the radius r iCorresponding to its phase angle α, the coordinates (x, y) of each measurement point in the turntable coordinate system (with the center of rotation on the turntable as the center point, the X direction at 0° phase angle as the X direction, the Y direction at 90° phase angle as the Y direction, and the upward direction of the rotation axis as the Z direction) can be obtained. i ,y i ), where x i =r i cosα i y i =r i sinα i α i Let be the phase angle of the i-th measurement point, which is the angle of rotation of the shaft.

[0056] After obtaining the coordinate values ​​of each measurement point, a least-squares circle fit is performed using these coordinate values ​​to obtain the least-squares circle equation for the upper cylindrical surface:

[0057]

[0058] Where (x0, y0) are the coordinates of the center of the least squares circle on the upper end face, i.e., the coordinates of the center of the cross section, and R is the radius of the least squares circle of the cross section.

[0059] After optimizing the above equation, the least squares fitting objective function can be obtained as follows:

[0060]

[0061] Where F′ is the least squares fitting objective function, (x i ,y i Let (x0, y0) be the coordinates of the i-th measurement point, (x0, y0) be the coordinates of the center of the cross-section circle, R be the radius of the least squares circle, and A = -2x o B = -2y o ,

[0062] By the principle of least squares, parameters A, B, and C should minimize F′. According to the method for finding the minimum value, A, B, and C should satisfy:

[0063]

[0064]

[0065]

[0066] Where n is the number of measurement points.

[0067] To solve the above system of equations, first eliminate the parameter C, then the equation... have to:

[0068]

[0069] Formula Obtained:

[0070]

[0071] Let:

[0072]

[0073]

[0074]

[0075]

[0076]

[0077] Formula (7), (8) is written in matrix form:

[0078]

[0079] According to formula (13) and formula (5):

[0080]

[0081]

[0082]

[0083] Thus the best fitting circle center coordinates (x0, y0), the radius R fitting value is obtained:

[0084]

[0085] The center coordinates (x0, y0) and its axial height z are solved to obtain its center coordinate value (O x1 , O y1 , O z1 ), and the radial runout data measured by the lower cylindrical surface is fitted by the least square method, the plane circle equation of the lower end surface is obtained, and the center coordinates (O x2 , O y2 , O z2 ) of the lower end surface are obtained, and the actual rotation center line of the rotor part is determined by the two point coordinates.

[0086] The above measurement and calculation method is used to press the rotor part to the assembly constraint state, that is, the actual assembly state of the part, and determine the actual rotation center line of each stage rotor part.

[0087] Then, the actual rotation center line of each rotor part in the rotor assembly needs to be fitted step by step, including: fitting the actual rotation center line of the current rotor part with the actual rotation center line of the rotor part combination; wherein the rotor part combination is the rotor part combination assembled before the current rotor part is assembled.

[0088] Specifically, fitting the actual rotation center line of the current rotor part with the actual rotation center line of the rotor part combination includes: selecting two first coordinate points on the actual rotation center line of the current rotor part; selecting two second coordinate points on the actual rotation center line of the rotor part combination before the current rotor part; and generating the fitted actual rotation center line according to the two first coordinate points and the two second coordinate points.

[0089] More specifically, the rotation center line of the first rotor part is determined as the actual rotation center line of the rotor The fitting of the rotation center lines of the first rotor and the second rotor obtains the actual rotation center line of the two-stage rotor assembly As shown in Figure 5 The two center points of the upper and lower end faces corresponding to the actual rotation center line of the first rotor part (the first-stage rotor center in the figure) are least square fitted with the two center points of the upper and lower end faces corresponding to the actual rotation center line of the second rotor part (the second-stage rotor center in the figure), and the actual rotation center line of the two-stage rotor assembly (the first-stage and second-stage rotor common center line in the figure) is fitted through the four points. As shown in Figure 6 The fitting process of the actual rotation center line of the three-stage rotor part is shown in the figure. The specific process is as follows:

[0090] Suppose that the two points on the first-stage rotor center in the three-dimensional space are (x1, y1, z1) and (x2, y2, z2), and the two points on the second-stage rotor center are (x3, y3, z3) and (x4, y4, y4, z4). The standard equation of the actual rotation center line of the two-stage rotor assembly (i.e. the first-stage and second-stage rotor common center line) to be solved is That is, according to the standard equation, the following can be obtained Wherein, k1, k2, k3, x0, y0, z0 are unknown constants,

[0091] The residual sum of squares is:

[0092]

[0093] According to the least square principle, the partial derivatives of a, b, c, and d are taken, and all the partial derivatives are set to zero to obtain:

[0094]

[0095] Wherein, xi = x1, x2, x3, x4, y i = y1, y2, y3, y4, z i = z1, z2, z3, z4, two first coordinate points are (x1, y1, z1) and (x2, y2, z2) respectively, and two second coordinate points are (x3, y3, z3) and (x4, y4, z4) respectively.

[0096] The values of a, b, c and d are obtained as follows:

[0097]

[0098] According to the above, the actual rotation center line of the two-stage rotor assembly can be obtained. Iteration is performed based on the actual rotation center line of the rotor assembly and the actual rotation center line of the rotor assembly is fitted to obtain the actual rotation center line of the rotor assembly , that is, the actual rotation center line X of the entire rotor assembly a .

[0099] Then, the runout deviation of each stage rotor part from the actual rotation center line of the rotor assembly is calculated, including: calculating the distance between the cross-sectional center of each stage rotor part and the actual rotation center line of the rotor assembly, and taking the distance as the runout deviation.

[0100] In the embodiment of the present application, a seven-stage rotor assembly is selected for testing, and the runout deviation of each stage rotor part is shown in Table 1.

[0101] Table 1

[0102]

[0103] Meanwhile, the center of the upper end face of each stage rotor is compared with the actual center line X a of the rotor assembly, and the simplified two-dimensional (X, Y) coordinate system is established as shown in Figure 7 .

[0104] More specifically, by comparing the center of the upper cylindrical surface of each stage rotor part with the actual rotation center line of the rotor assembly, the deviation of the center of the upper cylindrical surface of each stage rotor from the actual rotation center line X a of the rotor assembly is obtained, that is, the runout deviation ΔX i of each stage rotor part. The expression is:

[0105] |ΔX i | = |X a -O i | (21)

[0106] Where ΔX i is the runout deviation of the i-th stage rotor part, and O i is the center of the i-th stage rotor part.

[0107] Finally, the maximum value is selected from the run-out deviation of each rotor part as the flatness of the rotor assembly. That is:

[0108] |ΔX i | max = |X a -O i | max (22)

[0109] In this embodiment, the maximum |ΔX7| = 0.0195 of the rotor 7th stage run-out deviates from the actual rotation center line of the rotor, that is, the maximum flatness of the rotor is The flatness is compared with the preset flatness threshold value:

[0110] |ΔX7| = 0.0195 < 0.05 (23)

[0111] According to the comparison result, the flatness value is less than the flatness threshold value 0.05, which indicates that the rotor assembly is qualified. When the flatness is not qualified, the rotor needs to be disassembled (to the initial part state). The run-out check and flatness evaluation of each stage disc are performed according to the above steps again.

[0112] In addition, the rotor assembly assembled by the method of the embodiment of the present application and the rotor assembly assembled by the conventional method are compared with each other. As shown in Figure 8 the conventional assembly method forms a higher degree of "rotor bow" bending in the middle of the rotor assembly. After the "flatness" method of the rotor is adopted, the geometric run-out and the initial unbalance of the rotor are significantly reduced, and the assembly quality is obviously improved.

Claims

1. A method for evaluating and controlling the assembly quality of an aero-engine rotor, characterized in that, Includes the following steps: Obtain the radial runout data set at both ends of each stage rotor component in the rotor assembly under constrained conditions; The actual rotation center line of the corresponding rotor component is determined based on the radial runout data set. The actual rotation center line of the rotor assembly is obtained by fitting the actual rotation center line of each stage rotor component in the rotor assembly step by step. Calculate the runout deviation between each stage rotor component and the actual rotation center line of the rotor assembly; The maximum value is selected from the runout deviations corresponding to each stage of rotor components as the straightness of the rotor assembly; Determining the actual rotation centerline of the corresponding rotor component based on the radial runout data set includes: The radial runout data sets at both ends of the rotor component are fitted with least squares circles to obtain the coordinate values ​​of the cross-sectional center of each radial runout data set. The actual rotation center line of the rotor component is generated based on the coordinate values ​​of the two center points of the cross sections. The least-squares fitting of the radial runout data sets at both ends of the rotor component includes: The coordinate values ​​of each measurement point are generated based on each measurement data in the radial runout data set and the corresponding measurement phase angle; Generate a least-squares fitting objective function based on the coordinates of the measured points; Solve the least squares fitting objective function to obtain the coordinates of the center of the cross section.

2. The method for evaluating and controlling the assembly quality of an aero-engine rotor as described in claim 1, characterized in that, The least squares fitting objective function is: ， in, The least squares fitting objective function is... Let i be the coordinates of the i-th measurement point. The coordinates of the center of the cross section are, Let be the radius of the least squares circle. , , .

3. The method for evaluating and controlling the assembly quality of an aero-engine rotor as described in claim 2, characterized in that, The stepwise fitting of the actual rotation center line of each stage rotor component in the rotor assembly includes: The actual rotation center line of the current stage rotor component is fitted with the actual rotation center line of the rotor component assembly; wherein, the rotor component assembly is the rotor component assembly that was assembled before the current stage rotor component was assembled.

4. The method for evaluating and controlling the assembly quality of an aero-engine rotor as described in claim 3, characterized in that, Fitting the actual rotation center line of the current stage rotor component with the actual rotation center line of the rotor component assembly includes: Select two first coordinate points on the actual rotation center line of the current stage rotor component; Two second coordinate points are selected for the actual rotation center line of the rotor assembly preceding the current stage rotor component; The fitted actual rotation center line is generated based on the two first coordinate points and the two second coordinate points.

5. The method for evaluating and controlling the assembly quality of an aero-engine rotor as described in claim 4, characterized in that, The actual rotation center line is generated by using the two first coordinate points and the two second coordinate points, including: According to the standard equation, we can obtain... ;in, All are unknown constants; right Taking the partial derivatives and setting all partial derivatives to zero, we get: ； in, , , The two first coordinate points are respectively and The two second coordinate points are respectively and .

6. The method for evaluating and controlling the assembly quality of an aero-engine rotor as described in claim 4 or 5, characterized in that, The calculation of the runout deviation between each stage rotor component and the actual rotation center line of the rotor assembly includes: Calculate the distance between the center of the cross-section of each rotor component and the actual rotation centerline of the rotor assembly, and use this distance as the runout deviation.

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