A method for improving the accuracy of dynamic balancing of engine rotors

Abstract

The present invention discloses a method for improving the accuracy of dynamic balancing of an engine rotor. The method comprises adding weight to the rear end face of the tenth-stage compressor disk of the compressor rotor, the first grater of the first-stage compressor disk, the radial flange of the front end face of the first-stage turbine disk of the turbine rotor, and the radial flange of the rear end face of the third-stage turbine disk in two stages, performing dynamic balancing after each weight addition to obtain multiple residual imbalance values ​​and phase angles. The difference between the residual imbalance values ​​after the second weight addition and the first weight addition at each location of the compressor rotor and the turbine rotor is calculated, and the second weight addition is subtracted from the difference to obtain the true residual imbalance at each location. The present invention adds weight to the relevant locations of the rotor multiple times to obtain the residual imbalance value and phase angle of each weight addition, and then uses the calculation to obtain the true residual imbalance value and phase angle at the key locations of the compressor rotor and the turbine rotor, thereby achieving good dynamic balancing repeatability of the rotor.

Description

Technical Field

[0001] The present invention relates to the technical field of dynamic balancing of aircraft engine rotors, and in particular to a method for improving the accuracy of dynamic balancing of engine rotors. Background Art

[0002] During the acceptance test of aircraft engines, the proportion of failures caused by excessive vibration values ​​in the vertical direction of the engine's rear support plane and the horizontal direction near the engine's center of gravity plane has always been high. The current troubleshooting measures are mainly based on existing experience and lack a systematic analysis of the factors affecting vibration failures.

[0003] According to the requirements of the design drawings, assembly process documents and practical experience in the relevant assembly process, it has been sorted out that the vibration value exceeding the standard failure is mainly caused by inaccurate rotor dynamic balance, and the determination of the rotor dynamic balance is closely related to the actual dynamic imbalance of the rotor.

[0004] However, the current dynamic balancing test of rotors has poor measurement repeatability, resulting in large errors in the actual dynamic unbalance value.

[0005] By testing the vibration signal of the engine compressor rotor dynamic balancing machine, it was found that the poor dynamic balancing repeatability is most closely related to the random noise collected by the balancing machine. Therefore, how to remove noise interference, maintain consistency in the rotor dynamic balancing measurement, and take measures to obtain the actual dynamic imbalance of the rotor is of great significance for reducing the vibration value of the engine rotor test.

[0006] The invention application with publication number CN102928161A discloses a method for troubleshooting engine vibration value changes. This method adjusts the mass of the high-pressure compressor first-stage rotor blades to change the residual imbalance of the high-pressure rotor, thereby eliminating vibration faults. The high-pressure compressor first-stage rotor blade adjustment scheme is as follows: According to the phase of the pre-engine test balance, the mass difference between the light and heavy blades of the high-pressure rotor I is adjusted to obtain the desired imbalance value. The blade mass to be adjusted equals the desired imbalance value divided by the centroid rotation radius of the high-pressure compressor first-stage rotor blades. This method, applied to engines using elastic oil film vibration damping, can effectively eliminate vibration faults with a minimal decomposition depth, ensuring that the engine's vibration values ​​meet operating requirements. It can also shorten the engine vibration elimination cycle, reduce engine troubleshooting costs, and reduce operator labor intensity.

[0007] The above patent is also aimed at troubleshooting excessive vibration values ​​during aircraft engine test runs by adjusting the mass of the blades to increase the imbalance. However, on the one hand, this method is only applicable to engines that use elastic oil film vibration reduction and is not very applicable. On the other hand, it requires partial disassembly of the engine for troubleshooting, which is complicated to operate and may increase factors affecting test vibration during the assembly process. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the existing technology and provide a method for improving the accuracy of engine rotor dynamic balancing, which is highly versatile and can effectively eliminate noise interference during rotor dynamic balancing measurement. By obtaining the actual dynamic imbalance of the rotor, the vibration value of the engine rotor test is ultimately reduced.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for improving the dynamic balancing accuracy of an engine rotor, wherein the engine rotor comprises a compressor rotor and a turbine rotor, the compressor rotor comprising a rear end face of a tenth-stage compressor disk and a first row of grating teeth of a first-stage compressor disk, and the turbine rotor comprising a radial flange on a front end face of a first-stage turbine disk and a radial flange on a rear end face of a third-stage turbine disk. Weight is added cumulatively twice to key positions of the rear end face of the tenth-stage compressor disk and the first row of grating teeth of the first-stage compressor disk of the compressor rotor, and the radial flange on the front end face of the first-stage turbine disk of the turbine rotor and the radial flange on the rear end face of the third-stage turbine disk. Dynamic balancing is performed after each weight addition to obtain multiple residual imbalance magnitudes and phase angles. The difference in the magnitude of the residual imbalance after the second weight addition and after the first weight addition at each location of the compressor rotor and the turbine rotor is calculated, and the second weight addition is subtracted from the difference to obtain the true residual imbalance at each location.

[0011] Furthermore, obtaining the actual residual unbalance at each location includes the following steps:

[0012] 1) Compressor rotor dynamic balancing process:

[0013] S11. Dynamically balance the compressor rotor, then restart the balancing machine to obtain the remaining imbalance magnitude and phase angle;

[0014] S12. Add weight for the first time at a key position on the rear end face of the tenth-stage compressor disc. The first added weight is the minimum weight that can stabilize the dynamic balance measurement value of the compressor rotor; start the balancing machine to obtain the new residual imbalance size and phase angle;

[0015] S13. Add weight to the first stage compressor disc at the key position of the first grate teeth for the first time, the added weight is equal to the weight added in S12; start the balancing machine to obtain the new remaining imbalance size and phase angle;

[0016] S14. Add weight a second time at a key position on the rear end face of the tenth stage compressor disc, where the second weight added is half of the weight added in S12; start the balancing machine to obtain the new residual imbalance magnitude and phase angle;

[0017] S15. Add weight a second time to the key position of the first grating teeth of the first-stage compressor disk, the added weight being 1 / 2 of the weight added in S13; start the balancing machine to obtain the new residual imbalance magnitude and phase angle;

[0018] S16. Subtract the residual unbalance value obtained in S12 from the residual unbalance value obtained in S14, and then subtract the weight value added in S14 for the second time, to obtain the true residual unbalance value of the rear end face of the tenth stage compressor disk. If the true residual unbalance value is positive, the phase angle is the same as the phase angle in S12; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S12.

[0019] S17. Subtract the residual unbalance value obtained in S13 from the residual unbalance value obtained in S15, and then subtract the weight value added in S15 for the second time, to obtain the true residual unbalance value at the first grating tooth of the first-stage compressor disk. If the true residual unbalance value is positive, the phase angle is the same as the phase angle in S13; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S13.

[0020] 2) Turbine rotor dynamic balancing process:

[0021] S21. Dynamically balance the turbine rotor, then restart the balancing machine to obtain the remaining imbalance magnitude and phase angle;

[0022] S22. Add weight to the first stage turbine disk at the key position of the radial flange on the front end face. The first added weight is the minimum weight that can stabilize the dynamic balance measurement value of the turbine rotor; start the balancing machine to obtain the new residual imbalance size and phase angle;

[0023] S23. Add weight a second time at a key position on the radial flange of the front end of the first-stage turbine disk. The second added weight is equal to the weight added in S22. Start the balancing machine to obtain the new remaining imbalance size and phase angle.

[0024] S24 removes all weight added at the radial flange of the front end of the first-stage turbine disk, adds weight for the first time at the key position of the radial flange at the rear end of the third-stage turbine disk, and the added weight is equal to the weight added in S22; start the balancing machine to obtain the new remaining imbalance size and phase angle;

[0025] S25. Add weight a second time at a key position on the radial flange of the rear end face of the third-stage turbine disk, the added weight being equal to the weight added in S24; start the balancing machine to obtain a new residual imbalance size and phase angle;

[0026] S26. Subtract the residual unbalance value obtained in S22 from the residual unbalance value obtained in S23, and then subtract the weight value added a second time in S23, to obtain the true residual unbalance value at the radial flange of the front end face of the first-stage turbine disk. If the true residual unbalance value is positive, the phase angle is the same as the phase angle in S22; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S22.

[0027] S27. Subtract the residual unbalance value obtained in S24 from the residual unbalance value obtained in S25, and then subtract the weight value added for the second time in S25 to obtain the true residual unbalance value at the radial flange of the rear end face of the third-stage turbine disk; if the true residual unbalance value is positive, the phase angle is the same as the phase angle in S23; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S24.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] By adding weight to the compressor rotor and turbine rotor at relevant locations multiple times, the residual unbalance magnitude and phase angle of each added weight are obtained through dynamic balancing measurements. By applying relevant calculations, the true residual unbalance magnitude and phase angle of the compressor rotor and turbine rotor at relevant locations can be obtained. This ensures good dynamic balancing repeatability of the rotors, and the difference in the measurement results of multiple dynamic balancing measurements can be kept within 0.03g, with the variation within 2%.

[0030] After the actual dynamic imbalance of the rotor is obtained by the method of the present invention, the actual residual imbalance value and phase angle are input into the relevant optimal assembly phase angle calculation software to obtain the optimal phase angle combination of the compressor rotor and the turbine rotor. Using the optimal phase angle combination to assemble the compressor rotor and the turbine rotor can significantly reduce the vibration failure rate of the engine test, improve the test progress and efficiency, ensure the reliability of the engine operation, and have great economic and social benefits. DETAILED DESCRIPTION

[0031] In order to clearly illustrate the technical features of this solution, this technical solution is described in detail below through specific implementation methods.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0034] In this application, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0035] In this application, unless otherwise expressly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0036] Example 1

[0037] A method for improving the accuracy of dynamic balancing of an engine rotor aims to eliminate noise interference during rotor dynamic balancing measurement and determine the actual dynamic imbalance of the rotor, thereby reducing rotor vibration excitation. The engine rotor comprises a compressor rotor and a turbine rotor. The compressor rotor comprises the rear end face of the tenth-stage compressor disk and the first row of grates of the first-stage compressor disk, and the turbine rotor comprises the radial flange on the front end face of the first-stage turbine disk and the radial flange on the rear end face of the third-stage turbine disk. Weight is added twice cumulatively to key locations of the rear end face of the tenth-stage compressor disk and the first row of grates of the first-stage compressor disk of the compressor rotor, and the radial flange on the front end face of the first-stage turbine disk and the radial flange on the rear end face of the third-stage turbine disk of the turbine rotor. The weight addition material used is cement. Dynamic balancing is performed after each weight addition to obtain multiple residual imbalance values ​​and phase angles. The difference between the residual imbalance values ​​after the second weight addition and the first weight addition at each location on the compressor and turbine rotors is calculated, and the second weight addition is subtracted from the difference to obtain the actual residual imbalance at each location, thereby improving the accuracy of dynamic imbalance of the engine rotor.

[0038] After obtaining the true residual unbalance of each part of the engine rotor, the true residual unbalance of the compressor rotor and turbine rotor can be input into the optimal combination phase angle calculation software of the engine compressor and turbine according to the corresponding theory of rotor dynamics unbalance to calculate the optimal phase angle; when the whole machine is assembled afterwards, after the dynamic balance is qualified, the compressor rotor and turbine rotor are assembled in combination according to the optimal phase angle, which is of significant significance for reducing the vibration value of the engine rotor test.

[0039] The calculation of the above-mentioned optimal phase angle is carried out using the "Aircraft Engine Optimal Assembly Phase Angle Calculation Software Based on Rotor Response Characteristics". The registration number of the calculation software is 2023R11L0238438. It was developed by the applicant of this patent on October 12, 2022 and published on October 28, 2022. The calculation process of the technical software will not be repeated here.

[0040] This embodiment provides a compressor rotor dynamic balancing process to obtain the actual residual unbalance at each location, specifically including the following steps:

[0041] S11. Dynamically balance the compressor rotor according to the conventional dynamic balancing process, then restart the balancing machine to obtain the remaining imbalance size and phase angle, and then shut down.

[0042] S12. Add 2g of putty at the key position of the rear end face of the tenth stage compressor disc for the first time. The weight of 2g is the minimum weight obtained through experimental exploration that can stabilize the dynamic balance measurement value of the compressor rotor, and an integer value is taken to facilitate on-site implementation; start the balancing machine to obtain the new residual imbalance size and phase angle; if the obtained phase angle is far different from the phase angle before adding the putty, readjust the putty position until the two are close (error ≤ 10°) or equal; after the above conditions are met, repeat the start and stop of the dynamic balancing machine four times, and record the residual imbalance size and phase each time; calculate the average residual imbalance size and phase.

[0043] S13. Add 2g of cement to the key position of the first grating tooth of the first-stage compressor disk for the first time, and start the balancing machine to obtain the new residual imbalance size and phase angle; if the obtained phase angle is far different from the phase angle before adding the cement, readjust the position of the cement until the two are close (error ≤ 10°) or equal; after the above conditions are met, repeat the start and stop of the balancing machine four times, and record the residual imbalance size and phase each time; calculate the average residual imbalance size and phase.

[0044] After the above steps, the dynamic balancing of the compressor rotor has good repeatability. The difference in the measurement results of multiple dynamic balancing measurements is only within 0.03g, and the variation is within 2%.

[0045] S14. Add 1g of putty to the key position of the rear end surface of the tenth stage compressor disc for the second time (total 3g), start the balancing machine to obtain the new residual imbalance magnitude and phase angle; after the above conditions are met, repeat the start and stop of the balancing machine four times, recording the residual imbalance magnitude and phase each time; calculate the average residual imbalance magnitude and phase.

[0046] S15. Add 1g of clay to the key position of the first comb tooth of the first stage compressor disk for the second time (total 3g), start the balancing machine to obtain the new residual imbalance magnitude and phase angle; after the above conditions are met, repeat the start and stop of the balancing machine four times, and record the residual imbalance magnitude and phase each time; calculate the average residual imbalance magnitude and phase.

[0047] S16. Subtract the average residual unbalance obtained in S12 from the average residual unbalance obtained in S14, and then subtract the 1g clay increment added for the second time in S14 from this value to obtain the true residual unbalance of the rear end face of the tenth-stage compressor disk; if the true residual unbalance value is positive, the phase angle is the same as the phase angle in S12; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S12.

[0048] S17. Subtract the average residual unbalance obtained in S13 from the average residual unbalance obtained in S15, and then subtract the 1g clay increment added for the second time in S15 from this value to obtain the true residual unbalance at the first comb tooth of the first-stage compressor disk; if the true residual unbalance value is positive, the phase angle is the same as the phase angle in S13; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S13.

[0049] Example 2

[0050] This embodiment provides a turbine rotor dynamic balancing process to obtain the actual residual unbalance at each location, specifically including the following steps:

[0051] S21. Dynamically balance the turbine rotor according to the conventional dynamic balancing process, then restart the balancing machine to obtain the remaining imbalance size and phase angle, and then stop the machine.

[0052] S22. Add 5g of putty at the key position of the radial flange on the front end face of the first-stage turbine disk for the first time. The weight of 5g is the minimum weight obtained through experimental exploration that can stabilize the dynamic balance measurement value of the turbine rotor, and an integer value is taken to facilitate on-site implementation; start the balancing machine to obtain the new residual imbalance size and phase angle; if the obtained phase angle is far different from the phase angle before adding the putty, readjust the putty position until the two are close (error ≤ 10°) or equal; after the above conditions are met, repeat the start and stop of the dynamic balancing machine four times, and record the residual imbalance size and phase each time; calculate the average residual imbalance size and phase.

[0053] S23. Add 5g of putty for the second time at the key position of the radial flange on the front end face of the first-stage turbine disk (total 10g); start the balancing machine to obtain the new residual imbalance magnitude and phase angle; after the above conditions are met, repeat the start and stop of the balancing machine four times, and record the residual imbalance magnitude and phase each time; calculate the average residual imbalance magnitude and phase.

[0054] S24. Remove the 10g of putty added to the radial flange of the front end face of the first-stage turbine disk, and add 5g of putty for the first time to the key position of the radial flange of the rear end face of the third-stage turbine disk; start the balancing machine to obtain the new residual imbalance size and phase angle; if the obtained phase angle is far different from the phase angle before adding the putty, readjust the putty position until the two are close (error ≤ 10°) or equal; after meeting the above conditions, repeat starting and stopping the balancing machine four times, and record the residual imbalance size and phase each time; calculate the average residual imbalance size and phase.

[0055] S25. Add 5g of putty for the second time at the key position of the radial flange on the rear end face of the third-stage turbine disk (total 10g); start the balancing machine to obtain the new residual imbalance magnitude and phase angle; after the above conditions are met, repeat the start and stop of the balancing machine four times, and record the residual imbalance magnitude and phase each time; calculate the average residual imbalance magnitude and phase.

[0056] S26. Subtract the average residual unbalance obtained in S22 from the average residual unbalance obtained in S23, and then subtract the 5g clay increment added for the second time in S23 to obtain the true residual unbalance at the radial flange of the front end face of the first-stage turbine disk; if the true residual unbalance value is positive, the phase angle is the same as the phase angle in S22; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S22.

[0057] S27. Subtract the average residual unbalance obtained in S24 from the average residual unbalance obtained in S25, and then subtract the 5g clay increment added for the second time in S25 to obtain the true residual unbalance at the radial flange of the rear end face of the third-stage turbine disc; if the true residual unbalance value is positive, the phase angle is the same as the phase angle in S23; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S24.

[0058] Example 3

[0059] The difference between this embodiment and embodiment 1 and embodiment 2 is that the number of repeated starts and stops of the dynamic balancing machine in S12 to S15 and S22 to S25 is five or more times.

[0060] Since the implementation of the method of the present invention, more than 40 engines with vibration values ​​exceeding 1.5g in the vertical direction of the rear support plane and in the horizontal direction near the engine center of gravity plane have been dynamically balanced using this method for the compressor rotor and turbine rotor. By obtaining the actual dynamic imbalance of the engine rotor and assembling and testing the compressor rotor and turbine rotor at the optimal combination phase angle based on the actual dynamic imbalance, the vibration values ​​have dropped by more than 40%, ensuring the qualified delivery of the engine.

[0061] According to practical statistics, this method provides relevant actual dynamic unbalance parameters for calculating the optimal combined phase angle for engine rotor assembly, which reduces the proportion of test vibration failures exceeding the standard from more than 6.5% to less than 3%. The vibration failure rate is greatly reduced, which improves the progress and efficiency of engine test and the reliability of engine operation, and has great economic and social benefits.

[0062] Obviously, the above embodiments are merely examples for the purpose of clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A method for improving the dynamic balancing accuracy of an engine rotor, wherein the engine rotor comprises a compressor rotor and a turbine rotor, wherein the compressor rotor comprises a rear end face of a tenth-stage compressor disk and a first row of grating teeth of a first-stage compressor disk, and the turbine rotor comprises a radial flange on a front end face of a first-stage turbine disk and a radial flange on a rear end face of a third-stage turbine disk, characterized in that: Accumulative weight is added twice to key positions of the rear end face of the tenth-stage compressor disk of the compressor rotor, the first grating tooth of the first-stage compressor disk, the radial flange of the front end face of the first-stage turbine disk of the turbine rotor, and the radial flange of the rear end face of the third-stage turbine disk. Dynamic balancing is performed after each weight addition to obtain multiple residual unbalance values ​​and phase angles. The difference in the residual unbalance after the second weight addition and the first weight addition at each location of the compressor rotor and the turbine rotor is calculated, and the second added weight is subtracted from the difference to obtain the actual residual unbalance at each location.

2. The method for improving the dynamic balancing accuracy of an engine rotor according to claim 1, characterized in that: The acquisition of the actual residual imbalance at each location includes the following steps: 1) Compressor rotor dynamic balancing process: S11. Dynamically balance the compressor rotor, then restart the balancing machine to obtain the remaining imbalance magnitude and phase angle; S12. Add weight for the first time at a key position on the rear end face of the tenth-stage compressor disc. The first added weight is the minimum weight that can stabilize the dynamic balance measurement value of the compressor rotor; start the balancing machine to obtain the new residual imbalance size and phase angle; S13. Add weight for the first time at the key position of the first grate teeth of the first stage compressor disc, and the added weight is equal to the added weight in S12; Start the balancing machine to obtain the new residual unbalance value and phase angle; S14. Add weight for the second time at the key position of the rear end surface of the tenth stage compressor disc, the second weight added is 1 / 2 of the weight added in S12; Start the balancing machine to obtain the new residual unbalance value and phase angle; S15. Add weight a second time to the key position of the first grating teeth of the first-stage compressor disk, the added weight being 1 / 2 of the weight added in S13; start the balancing machine to obtain the new residual imbalance magnitude and phase angle; S16. Subtract the residual unbalance value obtained in S12 from the residual unbalance value obtained in S14, and then subtract the weight value added in S14 for the second time, to obtain the true residual unbalance value of the rear end face of the tenth stage compressor disk. If the true residual unbalance value is positive, the phase angle is the same as the phase angle in S12; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S12. S17. Subtract the residual unbalance value obtained in S13 from the residual unbalance value obtained in S15, and then subtract the weight value added in S15 for the second time, to obtain the true residual unbalance value at the first grating tooth of the first-stage compressor disk. If the true residual unbalance value is positive, the phase angle is the same as the phase angle in S13; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S13. 2) Turbine rotor dynamic balancing process: S21. Dynamically balance the turbine rotor, then restart the balancing machine to obtain the remaining imbalance magnitude and phase angle; S22. Add weight to the first stage turbine disk at the key position of the radial flange on the front end face. The first added weight is the minimum weight that can stabilize the dynamic balance measurement value of the turbine rotor; start the balancing machine to obtain the new residual imbalance size and phase angle; S23. Add weight a second time at a key position on the radial flange of the front end of the first-stage turbine disk. The second added weight is equal to the weight added in S22. Start the balancing machine to obtain the new remaining imbalance size and phase angle. S24 removes all weight added at the front end radial flange of the first stage turbine disk, add weight for the first time at the key position of the rear end radial flange of the third stage turbine disk, the added weight is equal to the added weight in S22; Start the balancing machine to obtain the new residual unbalance value and phase angle; S25. Add weight a second time at a key position on the radial flange of the rear end face of the third-stage turbine disk, the added weight being equal to the weight added in S24; start the balancing machine to obtain a new residual imbalance size and phase angle; S26. Subtract the residual unbalance value obtained in S22 from the residual unbalance value obtained in S23, and then subtract the weight value added a second time in S23, to obtain the true residual unbalance value at the radial flange of the front end face of the first-stage turbine disk. If the true residual unbalance value is positive, the phase angle is the same as the phase angle in S22; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S22. S27. Subtract the residual unbalance value obtained in S24 from the residual unbalance value obtained in S25, and then subtract the weight value added for the second time in S25 to obtain the true residual unbalance value at the radial flange of the rear end face of the third-stage turbine disk; if the true residual unbalance value is positive, the phase angle is the same as the phase angle in S23; if the true residual unbalance value is negative, the phase angle is opposite to the phase angle in S24.

3. The method for improving the dynamic balancing accuracy of an engine rotor according to claim 2, characterized in that: The weight added for the first time in S12 is an integer value.

4. The method for improving the dynamic balancing accuracy of an engine rotor according to claim 2, characterized in that: The weight added for the first time in S22 is an integer value.

5. The method for improving the dynamic balancing accuracy of an engine rotor according to claim 2, characterized in that: The first added weight in S12 is 2 g; the first added weight in S22 is 5 g.

6. The method for improving the dynamic balancing accuracy of an engine rotor according to any one of claims 2 to 5, characterized in that: If the phase angles obtained in steps S12, S13, S22, and S24 are not close to the phase angles before adding weight in each step, the weight addition position needs to be adjusted until the two phase angles are close.

7. The method for improving the dynamic balancing accuracy of an engine rotor according to claim 6, characterized in that: The two phase angles being close means that the error between the two phase angles is ≤10°.

8. The method for improving the dynamic balancing accuracy of an engine rotor according to claim 7, characterized in that: After adding weight each time and obtaining a new residual unbalance magnitude and phase angle in S12 to S15 and S22 to S25, the balancing machine needs to be started and stopped repeatedly multiple times to obtain multiple residual unbalance magnitudes and phase angles, and the average value of the multiple residual unbalance magnitudes and phase angles in each step is calculated; The remaining unbalance amounts calculated in S16, S17, S26 and S27 all use the average value.

9. The method for improving the dynamic balancing accuracy of an engine rotor according to claim 8, characterized in that: The number of repeated starts and stops of the balancing machine is four times.

10. The method for improving the dynamic balancing accuracy of an engine rotor according to claim 1, characterized in that: The added weight is cement.