Test equipment and test method for power turbine rotor across third-order bending criticality

Abstract

The present application discloses a test device and method for a power turbine rotor that crosses the third-order bending criticality, which belongs to the field of aero-engine technology. The device includes a support mechanism for supporting a simulated rotor, a power mechanism, a control system for controlling the power mechanism, a lubricating oil mechanism, and a test system. The simulated rotor includes a rotor shaft, and a disc-shaped power turbine first-stage disc and a power turbine second-stage disc that are connected to the rotor shaft and are interconnected. The device also includes a vacuum mechanism. The support mechanism includes a test platform, a front support, a rear support, and a vacuum box. The vacuum box is provided on the test platform. The vacuum mechanism is connected to the vacuum box. The vacuum mechanism is used to evacuate the vacuum box. The front support and the rear support are spaced apart on the test platform and located in the vacuum box. The front support and the rear support are used to clamp and support the rotor shaft. The rotor shaft is connected to the power mechanism. The present application conducts tests by simulating a rotor instead of a real rotor, which greatly shortens the processing cycle, reduces the test cost, and reduces the test risk.

Description

Technical Field

[0001] The present application relates to the field of aero-engine technology, and in particular to a test apparatus for a power turbine rotor across a third-order bending criticality. Furthermore, the present application also relates to a test method using the test apparatus for a power turbine rotor across a third-order bending criticality. Background Art

[0002] The information provided in this section is for the purpose of generally presenting the background of the present application. To the extent described in this section, the work of the presently named inventors and aspects of the description that may not constitute prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present application.

[0003] In the field of aircraft engine technology, according to aircraft engine airworthiness regulations, the design of compressor and turbine rotor casings must be tolerant of damage caused by rotor blade failure. Blade containment and rotor imbalance tests require that the most critical turbine blade fail during operation at the maximum permissible speed. This blade failure must occur at the outermost retaining groove on the disk; or, for blisk rotors, at least 80% of the blade must be lost. This most critical turbine blade must be determined based on its weight and the strength of the adjacent turbine casing at the temperatures and pressures associated with operation at the maximum permissible speed.

[0004] To verify the above-mentioned requirements, a full-machine containment test based on the free shedding of the power turbine rotor blades is required. This requires that the power turbine disc should not fail before the power turbine blades break and fall off. Normally, the power turbine rotor only needs to cross two critical bending speeds before reaching the rated operating speed. However, the speed at the time of blade shedding is as high as nearly 150% of the rated operating speed, forcing the rotor to cross the third critical bending speed after the rated operating speed. This test involves great risks and technical difficulties, mainly including the vibration characteristics of the rotor outside the rated operating speed, the reliability of the bearings, and the strength of the disc.

[0005] Currently, there is no test method specifically designed to test the rotors of civil turboshaft engines across the third critical bending speed. Only rotor vibration characteristic tests at rated operating speed have been conducted, which only require the rotors to cross the second critical bending speed.

[0006] Existing technical solutions only require dynamic performance testing of the rotor within the rated operating speed, spanning only two critical bending speeds, and fail to consider the need for full-machine testing to contain blade free fall. Dynamic performance outside the rated operating speed, bearing reliability, and disc strength are not comprehensively considered and verified. Because the rotor's vibration characteristics outside the rated operating speed are unknown, following the current method could lead to rotor instability beyond the rated operating speed, compromising test safety.

[0007] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0008] In view of at least one of the above technical problems, the present application provides a cross-third-order bending critical power turbine rotor testing equipment, which can carry out tests by simulating rotors instead of real rotors, greatly shortening the processing cycle, reducing testing costs and lowering testing risks.

[0009] At the same time, the present application also provides a test method using the above-mentioned cross-third-order bending critical power turbine rotor test equipment.

[0010] According to one aspect of the present application, a cross-third-order bending critical power turbine rotor test apparatus is provided, comprising a support mechanism for supporting a simulated rotor, a power mechanism for connecting to the simulated rotor and driving the simulated rotor to rotate, a control system for controlling the power mechanism, a lubricating oil mechanism for communicating with the simulated rotor and supplying lubricating oil, and a test system for detecting and collecting the simulated rotor. The simulated rotor comprises a rotor shaft, and a disc-shaped power turbine first-stage disc and a power turbine second-stage disc connected to each other for connection to the rotor shaft. The power turbine first-stage disc and the power turbine second-stage disc are used to simulate, in a one-to-one correspondence, actual power turbine first-stage blade discs and power turbine second-stage blade discs.

[0011] The power turbine rotor test equipment across the third-order bending criticality also includes a vacuum mechanism. The supporting mechanism includes a test platform, a front support, a rear support and a vacuum box. The vacuum box is arranged on the test platform. The vacuum mechanism is connected to the vacuum box. The vacuum mechanism is used to evacuate the vacuum box. The front support and the rear support are arranged at intervals on the test platform and are located in the vacuum box. The front support and the rear support are used to clamp and support the rotor shaft. The rotor shaft is connected to the power mechanism.

[0012] In some embodiments of the present application, the third-order bending critical power turbine rotor test equipment further includes an explosion-proof chamber, which is used to shield and protect the support mechanism and the simulated rotor.

[0013] According to another aspect of the present application, a method for testing a power turbine rotor across a third-order bending criticality is provided. The method employs the above-mentioned power turbine rotor testing apparatus across a third-order bending criticality. The method comprises the following steps:

[0014] S100, designing a simulated rotor, the simulated rotor including a rotor shaft and a simulated wheel, the simulated wheel including a power turbine first wheel and a power turbine second wheel, the power turbine first wheel and the power turbine second wheel simulating real power turbine first blade disk and power turbine second blade disk;

[0015] S200, performing a finite element analysis of the simulated wheel strength to obtain stress distribution of the first-stage wheel and the second-stage wheel of the power turbine;

[0016] S300, performing a simulated wheel strength test to verify that the strength of the simulated wheel does not break, and if so, adjusting the simulated wheel parameters;

[0017] S400, performing finite element analysis of the dynamic characteristics of the simulated rotor, and calculating the vibration modes of the simulated rotor at the first three critical speeds using rotor dynamics software;

[0018] S500: Conduct a bearing overspeed endurance test to verify the reliability of the real bearing when assembled on a simulated rotor under the third-order critical speed test conditions.

[0019] S600, conduct a simulated rotor cross-third critical speed test verification, clamp the simulated rotor through the third-order bending critical power turbine rotor test equipment and drive the simulated rotor for testing.

[0020] In some embodiments of the present application, in step S100, the material, mass, center of mass, polar moment of inertia and diameter moment of inertia of the first-stage power turbine wheel are consistent with those of the actual first-stage power turbine blade disk; the material, mass, center of mass, polar moment of inertia and diameter moment of inertia of the second-stage power turbine wheel are consistent with those of the actual second-stage power turbine blade disk.

[0021] In some embodiments of the present application, in step S100 , except for the simulated wheel, the other components of the simulated rotor are consistent with the real rotor.

[0022] In some embodiments of the present application, in step S200, stress analysis and calculation are performed on the first-stage power turbine wheel and the second-stage power turbine wheel using finite element analysis software, and the strength of both is checked according to the maximum stress method, that is, the empirical value of the blade free fall speed is selected, and a centrifugal load is applied. If the strength reserve coefficients of the first-stage power turbine wheel and the second-stage power turbine wheel are both greater than 1.0, the requirements are met; otherwise, the simulation wheel parameters are adjusted.

[0023] In some embodiments of the present application, in step S300, the simulated wheel is clamped using an existing vertical wheel rotation tester, and the predetermined speed is set to the speed of the blade free fall speed empirical value. During the rotation test, if the simulated wheel vibrates stably and does not break, it indicates that the strength of the simulated wheel meets the requirements.

[0024] In some embodiments of the present application, in step S400, the bearing unit in the software is used to simulate the supporting bearings of the real rotor, and the vibration modes of the simulated rotor at the first-order critical speed of 0.39 times the rated operating speed, the second-order critical speed of 0.7 times the rated operating speed, and the third-order critical speed of 1.51 times the rated operating speed are calculated.

[0025] In some embodiments of the present application, in step S500, in order to ensure reliable operation of the bearing during the third-order critical speed test, the speed of the bearing overspeed endurance test also covers the empirical speed of blade free fall, to detect whether the bearing is damaged after the test and whether it can rotate flexibly.

[0026] In some embodiments of the present application, in step S600, a displacement sensor is arranged on the rotor shaft of the simulated rotor to measure the vibration displacement of the rotor shaft during the test, and at the same time, vibration acceleration sensors are arranged on the front and rear supports of the support mechanism to measure the vibration acceleration, and at the same time, the temperature of the bearings on the simulated rotor is measured by a temperature sensor.

[0027] This application has the following beneficial effects:

[0028] The present invention relates to a cross-third order bending critical power turbine rotor test device. The test is carried out by replacing the real rotor with a simulated rotor, wherein the simulated rotor adopts a simulated wheel disc, namely a power turbine first wheel disc and a power turbine second wheel disc, and uses the power turbine first wheel disc and the power turbine second wheel disc to simulate the power turbine first blade disc and the power turbine second blade disc respectively. In addition to the simulated wheel disc, the other structures and components of the simulated rotor are consistent with the real rotor. The test can be carried out by the simulated rotor, which greatly shortens the processing cycle, reduces the test cost and reduces the test risk. The support mechanism can clamp and support the simulated rotor, drive the simulated rotor to rotate through the power mechanism, provide lubricating oil to the simulated rotor through the lubricating oil mechanism, and realize the simulated rotor vacuum operation test environment through the vacuum mechanism. Then, the various parameters in the simulated rotor test process are detected by the test system. Since there is no need to process the real complete rotor components, the component processing cost is effectively reduced, the test cycle is shortened, and the overall test cost is reduced.

[0029] The present invention's method for testing a power turbine rotor across the third-order bending criticality also has the aforementioned beneficial effects. It also includes replacing the blade disk with a simulated disc, and obtaining the stress distribution of the first-stage and second-stage turbine discs through finite element analysis. The simulated discs are then subjected to a test run to verify that their strength meets the requirements outside the rated operating speed. Furthermore, after calculating the vibration modes of the simulated rotor at the first three critical speeds using specialized rotor dynamics software, a bearing overrun endurance test is conducted to verify the reliability of the real bearings assembled on the simulated rotor under the third-order critical speed test conditions. Finally, the simulated rotor is clamped and driven using the third-order bending critical power turbine rotor test equipment to conduct a test run across the third-order critical speed. This application as a whole is first based on theoretical analysis and software simulation, combined with test verification, and after theoretical and actual test analysis and verification of the simulated turntable and bearings respectively, finally the simulated rotor is tested across the third-order critical speed to ensure variable control of key components, ensure the stability and reliability of key components during the final test of the simulated rotor, reduce the complexity of variable analysis of the simulated rotor across the third-order critical speed test, which is conducive to improving the accuracy of the test and promoting the efficient completion of the power turbine rotor across the third-order bending critical speed test. It also comprehensively considers and verifies the dynamic characteristics outside the rated operating speed, the bearing working reliability, and the strength of the wheel, etc., to provide support for the whole-machine containment test of the free shedding of the power turbine rotor blades of the civil turboshaft engine.

[0030] Of course, any product implementing this application does not necessarily need to achieve all of the advantages described above. In addition to the purposes, features, and advantages described above, this application also has other purposes, features, and advantages. This application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0032] Figure 1 This is a schematic diagram of the overall structure of a power turbine rotor test device across third-order bending criticality according to a preferred embodiment of the present application;

[0033] Figure 2 Schematic diagram of a simulated rotor according to a preferred embodiment of the present application installed on a power turbine rotor test device across a third-order bending criticality;

[0034] Figure 3 This is an overall schematic diagram of a simulated rotor in a preferred embodiment of the present application;

[0035] Figure 4 This is a schematic structural diagram of a simulated roulette wheel according to a preferred embodiment of the present application;

[0036] Figure 5 is a schematic diagram of a finite element mesh of a simulated roulette wheel according to a preferred embodiment of the present application;

[0037] Figure 6 This is a schematic diagram of stress distribution of a first-stage power turbine disk in a preferred embodiment of the present application;

[0038] Figure 7 This is a schematic diagram of stress distribution of a secondary disk of a power turbine in a preferred embodiment of the present application;

[0039] Figure 8 is a schematic diagram of a finite element model of a simulated rotor in a preferred embodiment of the present application;

[0040] Figure 9 Schematic diagram of the vibration mode corresponding to the first critical speed (0.39 n) of the simulated rotor in the preferred embodiment of the present application;

[0041] Figure 10 Schematic diagram of the vibration mode corresponding to the second critical speed (0.7 n) of the simulated rotor in the preferred embodiment of the present application;

[0042] Figure 11 Schematic diagram of the vibration mode corresponding to the third critical speed (1.51 n) of the simulated rotor in the preferred embodiment of the present application;

[0043] Figure 12 This is a physical schematic diagram of the 1# bearing of the preferred embodiment of the present application after the bearing over-rotation and sustained operation test;

[0044] Figure 13 This is a physical schematic diagram of the 2# bearing of the preferred embodiment of the present application after the bearing over-rotation and sustained operation test;

[0045] Figure 14 This is a physical schematic diagram of the 3# bearing of the preferred embodiment of the present application after the bearing over-rotation and sustained operation test;

[0046] Figure 15 This is a physical schematic diagram of the 4# bearing of the preferred embodiment of the present application after the bearing over-rotation and long-term operation test.

[0047] Legend: 100, simulated rotor; 101, rotor shaft; 102, power turbine first-stage impeller; 103, power turbine second-stage impeller; 1, power mechanism; 2, transmission mechanism; 3, support mechanism; 31, test platform; 32, front support; 33, rear support; 34, vacuum box; 4, lubricating oil mechanism; 5, vacuum mechanism; 6, control system; 7, test system; 8, explosion-proof warehouse. DETAILED DESCRIPTION

[0048] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in a variety of different ways defined and covered below.

[0049] Figure 1 This is a schematic diagram of the overall structure of a power turbine rotor test device across third-order bending criticality according to a preferred embodiment of the present application; Figure 2 Schematic diagram of a simulated rotor according to a preferred embodiment of the present application installed on a power turbine rotor test device across a third-order bending criticality; Figure 3 This is an overall schematic diagram of a simulated rotor in a preferred embodiment of the present application; Figure 4 This is a schematic structural diagram of a simulated roulette wheel according to a preferred embodiment of the present application; Figure 5 is a schematic diagram of a finite element mesh of a simulated roulette wheel according to a preferred embodiment of the present application; Figure 6 This is a schematic diagram of stress distribution of a first-stage power turbine disk in a preferred embodiment of the present application; Figure 7 This is a schematic diagram of stress distribution of a secondary disk of a power turbine in a preferred embodiment of the present application; Figure 8 is a schematic diagram of a finite element model of a simulated rotor in a preferred embodiment of the present application; Figure 9 Schematic diagram of the vibration mode corresponding to the first critical speed (0.39 n) of the simulated rotor in the preferred embodiment of the present application; Figure 10 Schematic diagram of the vibration mode corresponding to the second critical speed (0.7 n) of the simulated rotor in the preferred embodiment of the present application; Figure 11 Schematic diagram of the vibration mode corresponding to the third critical speed (1.51 n) of the simulated rotor in the preferred embodiment of the present application; Figure 12 This is a physical schematic diagram of the 1# bearing of the preferred embodiment of the present application after the bearing over-rotation and sustained operation test; Figure 13 This is a schematic diagram of the No. 2 bearing of the preferred embodiment of the present application after the bearing over-rotation and sustained operation test; Figure 14 This is a physical schematic diagram of the 3# bearing of the preferred embodiment of the present application after the bearing over-rotation and sustained operation test; Figure 15 This is a physical schematic diagram of the 4# bearing of the preferred embodiment of the present application after the bearing over-rotation and long-term operation test.

[0050] A cross-third-order bending critical power turbine rotor test equipment is used to clamp a simulated rotor 100 and drive the simulated rotor 100 for testing. The cross-third-order bending critical power turbine rotor test equipment includes a support mechanism 3 for supporting the simulated rotor 100, a power mechanism 1 for connecting to the simulated rotor 100 and driving the simulated rotor 100 to rotate, a control system 6 for controlling the power mechanism 1, a lubricating oil mechanism 4 for communicating with the simulated rotor 100 and supplying lubricating oil, and a test system 7 for detecting and collecting the simulated rotor 100. The simulated rotor 100 includes a rotor shaft 101, and a disc-shaped power turbine first-stage disc 102 and a power turbine second-stage disc 103 for connecting to the rotor shaft 101 and connected to each other. The power turbine first-stage disc 102 and the power turbine second-stage disc 103 are used to simulate a real power turbine first-stage blade disc and a real power turbine second-stage blade disc in a one-to-one correspondence.

[0051] The cross-third-order bending critical power turbine rotor test equipment also includes a vacuum mechanism 5. The support mechanism 3 includes a test platform 31, a front support 32, a rear support 33 and a vacuum box 34. The vacuum box 34 is arranged on the test platform 31. The vacuum mechanism 5 is connected to the vacuum box 34. The vacuum mechanism 5 is used to evacuate the vacuum box 34. The front support 32 and the rear support 33 are arranged at intervals on the test platform 31 and are located in the vacuum box 34. The front support 32 and the rear support 33 are used to clamp and support the rotor shaft 101. The rotor shaft 101 is connected to the power mechanism 1.

[0052] Here, the “simulated rotor 100 ” means a structure used to simulate a real power turbine rotor. In some embodiments, the simulated rotor 100 mainly includes a power shaft 101 and a simulated wheel, and the simulated wheel includes a power turbine first-stage wheel 102 and a power turbine second-stage wheel 103 .

[0053] In actual design, the simulated wheel is an axisymmetric multi-stage wheel structure. The wheel does not need to be processed into a blade shape. It only needs to ensure that the mass, center of mass, polar moment of inertia and diameter moment of inertia of the simulated wheel and the real blade are consistent, and the material of the simulated wheel is consistent with the real blade. It can play an effective replacement role, and the simulated wheel is subjected to strength analysis and test verification to ensure that the wheel strength meets the requirements.

[0054] During use, the rotor shaft 101 is clamped through the front support 32 and the rear support 33, and the power mechanism 1 can be connected to the rotor shaft 101 through the transmission mechanism 2. The simulated rotor 100 is driven to rotate by the power mechanism 1 to conduct the test, and various test parameters are monitored and collected through the test system 7.

[0055] The present invention relates to a cross-third-order bending critical power turbine rotor test device. The test is conducted by using a simulated rotor 100 instead of a real rotor. The simulated rotor 100 uses simulated wheels, namely, a power turbine first-stage wheel 102 and a power turbine second-stage wheel 103. The power turbine first-stage wheel 102 and the power turbine second-stage wheel 103 respectively simulate the power turbine first-stage blade disk and the power turbine second-stage blade disk. In addition to the simulated wheels, the other structures and components of the simulated rotor 100 are consistent with the real rotor. Therefore, the simulated rotor 100 can be used to conduct tests, significantly shortening the processing cycle, reducing the test cost, and lowering the test risk. The support mechanism 3 can clamp and support the simulated rotor 100, and the power mechanism 1 drives the simulated rotor 100 to rotate. The lubricating oil mechanism 4 provides lubricating oil to the simulated rotor 100, and the vacuum mechanism is used to vacuumize the simulated rotor 100 to achieve a vacuum operating test environment. Subsequently, the various parameters of the simulated rotor 100 during the test are detected by the test system 7. Since there is no need to process the real complete rotor components, the component processing cost is effectively reduced, the test cycle is shortened, and the overall test cost is reduced.

[0056] Preferably, please refer to Figure 1 As shown, the cross-third-order bending critical power turbine rotor test equipment further includes an explosion-proof chamber 8 , which is used to shield and protect the supporting mechanism 3 and the simulated rotor 100 .

[0057] It is understandable that because the test speed of the third-order bending critical speed test exceeds the rated operating speed of the simulated rotor 100, the test equipment of this application is equipped with an explosion-proof chamber 8 to provide explosion-proof protection, shielding and protecting the support mechanism 3 and the simulated rotor 100 as a whole. In addition, the equipment has an emergency stop function, which can be used in the event of abnormal conditions such as test failures. At the same time, the test system 7 of the test equipment of this application also includes monitoring sensors for speed, temperature, oil supply pressure, vibration, etc., implementing various over-limit alarm functions to monitor various test parameters in real time and ensure test safety.

[0058] In addition, the present application also provides a method for testing a power turbine rotor across a third-order bending criticality, which uses the above-mentioned power turbine rotor testing equipment across a third-order bending criticality. The method for testing a power turbine rotor across a third-order bending criticality includes the following steps:

[0059] S100, designing a simulated rotor 100, wherein the simulated rotor 100 includes a rotor shaft 101 and simulated wheels, wherein the simulated wheels include a power turbine first-stage wheel 102 and a power turbine second-stage wheel 103, and the power turbine first-stage wheel 102 and the power turbine second-stage wheel 103 are used to simulate a real power turbine first-stage blade disk and a power turbine second-stage blade disk;

[0060] S200, performing a finite element analysis of the simulated wheel strength to obtain the stress distribution of the power turbine first-stage wheel 102 and the power turbine second-stage wheel 103;

[0061] S300, performing a simulated wheel strength test to verify that the strength of the simulated wheel does not break, and if so, adjusting the simulated wheel parameters;

[0062] S400, performing a finite element analysis of the dynamic characteristics of the simulated rotor 100, and calculating the vibration modes of the simulated rotor 100 at the first three critical speeds using rotor dynamics software, such as SAMCEF / ROTOR;

[0063] S500, performing a bearing over-speed sustained operation test to verify the working reliability of the real bearing assembled on the simulated rotor 100 under the test conditions across the third critical speed;

[0064] S600 , conducting a test run to verify the simulated rotor 100 across the third-order critical speed, clamping the simulated rotor 100 through a power turbine rotor test device across the third-order bending criticality, and driving the simulated rotor 100 for testing.

[0065] This application aims to solve the technical difficulties in testing power turbine rotors across the third-order bending critical speed, and proposes a test device and test method for power turbine rotors across the third-order bending critical speed. A specific test process, steps, and implementation method for power turbine rotors across the third-order bending critical speed are proposed, which solves the problems of high risk, high cost, and long processing cycle of directly using real rotors for testing. At the same time, it solves the technical difficulties in testing power turbine rotors across the bending critical speed outside the rated operating speed. Through this application, a test of a power turbine rotor across the third-order bending critical speed for a civil turboshaft engine was successfully completed, providing support for the whole-machine containment test of the free shedding of blades of the power turbine rotor of a civil turboshaft engine.

[0066] The present invention relates to a test method for a power turbine rotor across third-order bending criticality, in which a simulated disc replaces a blade disc, and obtains the stress distribution of the first-stage disc 102 of the power turbine and the second-stage disc 103 of the power turbine through finite element analysis. At the same time, the simulated disc is subjected to a test run for verification, and it is verified that the strength of the simulated disc outside the rated operating speed meets the requirements. In addition, after the vibration modes of the simulated rotor 100 under the first three critical speeds are calculated through rotor dynamics-specific software, a bearing over-speed endurance test is also carried out to verify the working reliability of the real bearing assembled on the simulated rotor 100 under the test conditions across third-order critical speeds. Finally, the simulated rotor 100 is clamped by the power turbine rotor test equipment across third-order bending criticality and driven to perform a test run across third-order critical speed. This application as a whole is first based on theoretical analysis and software simulation, combined with test verification, and after theoretical and actual test analysis and verification of the simulated turntable and bearings respectively, finally the simulated rotor 100 is tested across the third-order critical speed to ensure variable control of key components, ensure the stability and reliability of key components during the final test of the simulated rotor 100, reduce the complexity of variable analysis of the simulated rotor 100 across the third-order critical speed test, which is conducive to improving the accuracy of the test and promoting the efficient completion of the power turbine rotor across the third-order bending critical speed test. It also comprehensively considers and verifies the dynamic characteristics outside the rated operating speed, the bearing working reliability, and the strength of the wheel, etc., to provide support for the whole-machine containment test of the free shedding of the power turbine rotor blades of the civil turboshaft engine.

[0067] Preferably, in step S100, the material, mass, center of mass, polar moment of inertia and diameter moment of inertia of the power turbine first-stage impeller 102 are consistent with those of the actual power turbine first-stage blade disk; the material, mass, center of mass, polar moment of inertia and diameter moment of inertia of the power turbine second-stage impeller 103 are consistent with those of the actual power turbine second-stage blade disk.

[0068] In this preferred embodiment, except for the simulated wheel disc, the other components of the simulated rotor 100 are consistent with those of a real rotor.

[0069] Understandably, a simulated rotor 100 was designed to avoid the high risks, high costs, and long processing cycles associated with direct testing of a real rotor. To analyze and verify the strength of the simulated disc and ensure that its strength met requirements, the simulated disc was constructed from the same material as the actual bladed disc, and its key parameters were adjusted to within a small margin of error to ensure test validity.

[0070] In some embodiments, the structure of the simulated roulette wheel is as follows Figure 4As shown, it is a multi-stage wheel disc structure, and the blade shape does not need to be processed, wherein the power turbine first-stage wheel disc 102 and the power turbine second-stage wheel disc 103 are interconnected. The quality characteristics of the simulated wheel disc and the real wheel disc are compared in the following table:

[0071] Table 1 is a comparison of the quality characteristics of the simulated wheel and the real blade disk

[0072]

[0073] Preferably, in step S200, stress analysis and calculation are performed on the power turbine first-stage wheel 102 and the power turbine second-stage wheel 103 using finite element analysis software, and the strength of the two is checked according to the maximum stress method, that is, the empirical value of the blade free fall speed is selected, and a centrifugal load is applied. If the strength reserve coefficients of the power turbine first-stage wheel 102 and the power turbine second-stage wheel 103 are both greater than 1.0, the requirements are met, otherwise the simulation wheel parameters are adjusted.

[0074] It is understood that the finite element analysis can be used to preliminarily determine whether the strength of the simulated wheel as a whole meets the test requirements, and the stress distribution of the power turbine first stage wheel 102 and the power turbine second stage wheel 103 of the simulated wheel can be determined. Figure 6 and Figure 7 , which can efficiently identify weak links and facilitate targeted strengthening design.

[0075] It should be noted that the temperature load in the calculation of step S200 is room temperature (because the test is usually carried out at room temperature), and a binding contact is established at the connection position of the power turbine first-stage wheel 102 and the power turbine second-stage wheel 103. Please refer to the established finite element mesh. Figure 5 As shown, the conventional method of applying centrifugal load at a rotation speed (about 32000 r / min in some embodiments) is adopted, and the stress distribution of the simulated wheel disk can be calculated by common finite element software.

[0076] Preferably, in step S300, the simulated wheel is clamped using an existing vertical wheel rotation tester, and the predetermined rotation speed is set to the empirical value of the blade free-falling rotation speed. During the rotation test, if the simulated wheel vibrates stably and does not break, it indicates that the strength of the simulated wheel meets the requirements.

[0077] It is understood that by setting a predetermined speed (approximately 32,000 r / min in some embodiments) based on empirical values ​​for blade free shedding, actual test runs can be conducted to verify that the strength of the simulated disc meets requirements. If cracking or other phenomena occur, targeted structural optimization can be performed in conjunction with finite element analysis results.

[0078] Preferably, in step S400, the bearing unit in the software is used to simulate the supporting bearings of the real rotor, and the vibration modes of the simulated rotor 100 at the first-order critical speed of 0.39 times the rated operating speed, the second-order critical speed of 0.7 times the rated operating speed, and the third-order critical speed of 1.51 times the rated operating speed are calculated.

[0079] It is understood that by analyzing and simulating the dynamic characteristics of the rotor 100 in advance through rotor dynamics software, the critical speed, vibration mode distribution and the third-order critical speed value of the rotor at the rated working speed can be known in advance. Figure 9 、 Figure 10 and Figure 11 , which are the vibration modes of the simulated rotor 100 at the third-order critical speed, respectively. It shows that the first three vibration modes of the simulated rotor 100 are all bending vibration modes, which are typical flexible rotor vibration modes. The key is to obtain the third-order critical speed distribution in order to provide a reference for the dynamic characteristics test.

[0080] Preferably, in step S500, in order to ensure reliable operation of the bearing during the third-order critical speed test, the speed of the bearing overspeed endurance test also covers the empirical speed of blade free fall, to detect whether the bearing is damaged after the test and whether it can rotate flexibly.

[0081] In this preferred embodiment, the bearing overspeed sustained operation test covers the speed at which blades experience free fall, with a margin of approximately 10% to ensure test safety. This overspeed sustained operation test verifies the bearing's operational reliability across three critical speeds.

[0082] In some embodiments, bearings 1#, 2#, 5# and 6# that are consistent with the entire machine are selected to carry out bearing over-rotation endurance test respectively. The endurance test results of each bearing are shown in the following table:

[0083] Table 2 is the bearing over-speed endurance test results

[0084] bearings Test situation 1# bearing The bearing operated at the blade-free shedding speed for over 60 minutes, with the bearing temperature stabilizing at approximately 168°C. After the test, the bearing was found to be in good condition, with no damage to the inner and outer rings, cage, or rolling elements. The bearing rotated freely without any stagnation. 2# bearing The bearing ran continuously for about 4 hours at the blade free shedding speed, with the highest bearing temperature of about 125°C. The bearing temperature was stable during the test, and there was no bearing blocking after the test. 5# bearing The test bearing was operated continuously for 50 hours at the blade free shedding speed and rotated flexibly. 6# bearing After continuous operation for 50 hours at the blade free shedding speed, the maximum bearing temperature is about 165℃. After the test, the bearing rotates flexibly.

[0085] Please refer to the photos of each bearing after the test Figure 12-15 ,From the bearing endurance operation test results, it can be seen that the ,bearings of the simulated rotor 100 can operate stably and durably at the blade free ,shedding speed, and the bearing temperatures do not exceed the allowable ,temperature, thus meeting the requirements of the simulated rotor crossing the ,third-order critical speed test.

[0086] At the same time, in step S600, a displacement sensor is arranged on the rotor shaft 101 of the simulated rotor 100 to measure the vibration displacement of the rotor shaft 101 during the test, and vibration acceleration sensors are arranged on the front support 32 and the rear support 33 of the support mechanism 3 to measure the vibration acceleration. At the same time, the temperature of the bearings on the simulated rotor 100 is measured by a temperature sensor.

[0087] Please refer to Figure 2 As shown, when the 1#, 2#, 5# and 6# bearings are assembled on the rotor shaft 101 to perform a test verification of the simulated rotor 100 across the third-order critical speed, displacement sensors are arranged on the rotor shaft 101 of the simulated rotor 100. Specifically, four displacement sensors (D1 to D4) can be arranged to measure the vibration displacement of the rotor shaft 101 during the test; at the same time, vibration acceleration sensors A1 and A2 are respectively installed on the front support 32, and vibration acceleration sensors A3 and A4 are respectively installed on the rear support 33 to measure the vibration acceleration; the temperature of each bearing is measured by the thermocouples T1 to T4 attached to the outer ring of each bearing, and the strain of the front and rear spring supports of the simulated rotor 100 is measured by the strain gauges S1 to S4. Figure 2 In the figure, “⊥” indicates that each sensor is perpendicular to the rotor shaft 101, and “=” indicates that each sensor is parallel to the horizontal direction of the rotor shaft 101, so as to realize multi-directional comprehensive detection and ensure the measurement accuracy. In this way, various key parameters in the process of the test verification across the third-order critical speed can be monitored in real time to ensure the normal progress of the test, monitor abnormal conditions in real time, and ensure the safety of the test.

[0088] In summary, the present application provides a method for testing a power turbine rotor across third-order bending criticality, including the design and verification steps of a simulated rotor, the design method and strength verification of a simulated wheel, a method for endurance operation of an external bearing at a rated operating speed, and a method for testing a critical speed across third-order bending criticality.

[0089] This application used a simulated rotor 100 in place of a real rotor for testing, significantly shortening the processing cycle, reducing testing costs, and mitigating testing risks. The simulated rotor disc had minimal design errors compared to the real disc, enabling structural substitution for testing. The simulated rotor disc's strength at the rated operating speed was verified to meet requirements. The bearing's reliability for sustained operation at the blade free-fall speed was also verified. A method for conducting rotor cross-third-order bending critical speed testing was also provided, validating the method's accuracy.

[0090] Using the technical solution of this application, a test was completed on a civilian turboshaft engine power turbine rotor across the third-order critical speed of bending. The distribution of the third-order critical speed outside the rated operating speed was obtained. The rotor smoothly passed the third-order critical speed of bending and vibrated smoothly. Based on the test results of 100 simulated rotors, the same method was used to complete a real rotor across the third-order critical speed of bending, laying a solid foundation for the whole-machine containment test of free blade shedding.

[0091] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0092] This article uses specific examples to illustrate the principles and implementation methods of this application. The above examples are only used to help understand the method and core ideas of this application. The above is only the preferred implementation method of this application. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principles of this application, they can make several improvements, modifications or changes, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as protected by this application.

Claims

1. A method for testing a power turbine rotor across a third-order bending criticality, characterized in that: The following steps are involved: S100, designing a simulated rotor (100), the simulated rotor (100) comprising a rotor shaft (101), and a disc-shaped power turbine first-stage disc (102) and a power turbine second-stage disc (103) connected to the rotor shaft (101) and connected to each other, the power turbine first-stage disc (102) and the power turbine second-stage disc (103) being used to simulate a real power turbine first-stage blade disc and a real power turbine second-stage blade disc in a one-to-one correspondence; S200, performing a finite element analysis of the strength of the simulated wheel disc to obtain the stress distribution of the power turbine first-stage wheel disc (102) and the power turbine second-stage wheel disc (103); performing stress analysis calculation on the power turbine first-stage wheel disc (102) and the power turbine second-stage wheel disc (103) using finite element analysis software, and checking the strength of both according to the maximum stress method, that is, selecting an empirical value of the blade free fall speed, applying a centrifugal load, and if the strength reserve coefficients of the power turbine first-stage wheel disc (102) and the power turbine second-stage wheel disc (103) are both greater than 1.0, then the requirements are met, otherwise, the simulated wheel parameters are adjusted; S300, conducting a simulated wheel disc strength test to verify the strength of the simulated wheel disc. The simulated wheel disc is clamped using an existing vertical wheel disc rotation tester. The predetermined rotation speed is set to the empirical value of the blade free shedding speed. During the rotation test, if the simulated wheel disc vibrates stably and does not break, it indicates that the strength of the simulated wheel disc meets the requirements. S400, performing a finite element analysis of the dynamic characteristics of the simulated rotor (100), and calculating the vibration mode of the simulated rotor (100) at the first three critical speeds using rotor dynamics dedicated software; simulating the bearings supporting the real rotor using a bearing unit in the software, and calculating the vibration mode of the simulated rotor (100) at the first critical speed of 0.39 times the rated operating speed, the second critical speed of 0.7 times the rated operating speed, and the third critical speed of 1.51 times the rated operating speed; S500, conducting a bearing over-speed endurance operation test to verify the working reliability of a real bearing assembled on a simulated rotor (100) under a test condition spanning the third critical speed; in order to ensure the reliable operation of the bearing during the test spanning the third critical speed, the speed of the bearing over-speed endurance operation test also covers the blade free fall experience value speed, and detects whether the bearing is damaged after the test and whether it can rotate flexibly; S600, conducting a test run to verify the simulated rotor (100) across a third-order critical speed, clamping the simulated rotor (100) through a third-order bending critical power turbine rotor test device and driving the simulated rotor (100) to perform the test.

2. The method for testing a power turbine rotor across third-order bending criticality according to claim 1, characterized in that: In step S100, the power turbine first stage wheel disk (102) is consistent with the material, mass, center of mass, polar moment of inertia and diametric moment of inertia of the real power turbine first stage blade disk; The material, mass, center of mass, polar moment of inertia and diametric moment of inertia of the power turbine secondary wheel disk (103) are consistent with those of a real power turbine secondary blade disk.

3. The method for testing a power turbine rotor across third-order bending criticality according to claim 1, characterized in that: In step S100, except for the simulated wheel disc, the other components of the simulated rotor (100) are consistent with those of a real rotor.

4. The method for testing a power turbine rotor across third-order bending criticality according to claim 1, characterized in that: In step S600, a displacement sensor is arranged on the rotor shaft (101) of the simulated rotor (100) to measure the vibration displacement of the rotor shaft (101) during the test, and vibration acceleration sensors are arranged on the front support (32) and the rear support (33) of the support mechanism (3) to measure the vibration acceleration, and the temperature of the bearing on the simulated rotor (100) is measured by a temperature sensor.

5. The method for testing a power turbine rotor across third-order bending criticality according to claim 4, wherein: A power turbine rotor test device across third-order bending criticality comprises: a support mechanism (3) for supporting a simulated rotor (100), a power mechanism (1) for connecting with the simulated rotor (100) and driving the simulated rotor (100) to rotate, a control system (6) for controlling the power mechanism (1), a lubricating oil mechanism (4) for communicating with the simulated rotor (100) and supplying lubricating oil, a test system (7) for detecting and collecting the simulated rotor (100), a vacuum mechanism (5), and an explosion-proof chamber (8); The supporting mechanism (3) includes a test platform (31), a front support (32), a rear support (33) and a vacuum box (34). The vacuum box (34) is arranged on the test platform (31). The vacuum mechanism (5) is connected to the vacuum box (34). The vacuum mechanism (5) is used to evacuate the vacuum box (34). The front support (32) and the rear support (33) are arranged on the test platform (31) at intervals and are located in the vacuum box (34). The front support (32) and the rear support (33) are used to clamp and support the rotor shaft (101). The rotor shaft (101) is connected to the power mechanism (1). The explosion-proof chamber (8) is used to shield and protect the supporting mechanism (3) and the simulated rotor (100).

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