Cross-third-order bending critical power turbine rotor test equipment and test method

Abstract

The invention discloses a cross-third-order bending critical power turbine rotor test device and method, and belongs to the technical field of aero-engines, the cross-third-order bending critical power turbine rotor test device comprises a supporting mechanism used for supporting a simulation rotor, a power mechanism, a control system used for controlling the power mechanism, a lubricating oil mechanism and a test system, the power turbine first-stage wheel disc and the power turbine second-stage wheel disc are used for being connected with a rotor shaft, are in wheel disc shapes and are connected with each other, the bearing mechanism comprises a test platform, a front support, a rear support and a vacuum box, the vacuum box is arranged on the test platform, and the vacuum mechanism is connected with the vacuum box. The vacuum mechanism is used for vacuumizing the vacuum box, the front support and the rear support are arranged on the test platform in a spaced mode and located in the vacuum box, the front support and the rear support are used for clamping and supporting a rotor shaft, and the rotor shaft is connected with the power mechanism. The simulation rotor replaces a real rotor to carry out the test, the processing period is greatly shortened, the test cost is reduced, and the test risk is reduced.

Description

Technical Field

[0001] The present application relates to the field of aeroengine technology, and in particular, to a three-step bending critical power turbine rotor test device. In addition, the present application also relates to a test method using the three-step bending critical power turbine rotor test device. 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 the relevant regulations on aircraft engine airworthiness, the design of compressor and turbine rotor casings must be inclusive of damage caused by rotor blade failure. The blade inclusion and rotor imbalance test stipulates that the most dangerous turbine blade fails during operation at the maximum allowable speed. The blade failure must occur at the outermost fixing groove on the disk; or for an integral blade rotor, the blade must be at least 80% missing. The most dangerous turbine blade must be determined based on the weight of the turbine blade and the strength of its adjacent turbine casing at the temperature and pressure associated with the maximum allowable speed operation.

[0004] In order to verify the above-mentioned items, a whole-machine containment test based on the free shedding of the power turbine rotor blades is required, requiring that the power turbine disc should not fail before the power turbine blades break and fall off. Usually, the power turbine rotor only needs to cross two critical bending speeds before running to the rated operating speed. However, the speed when the blades fall off is as high as nearly 150% of the rated operating speed, so that the rotor needs to cross the third critical bending speed after the rated operating speed. The test has 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, etc.

[0005] At present, there is no test method specifically for civil turboshaft engine power turbine rotors across the third critical bending speed. Only the rotor vibration characteristic test at rated operating speed has been carried out, which only requires crossing two critical bending speeds.

[0006] The existing technical solution only needs to conduct dynamic characteristic tests of the rotor within the rated operating speed, and only needs to cross two critical bending speeds, without considering the need for a whole machine containment test for free blade shedding. The dynamic characteristics outside the rated operating speed, the working reliability of the bearings, and the strength of the wheel have not been comprehensively considered and verified. Since the vibration characteristics of the rotor outside the rated operating speed are unknown, if the current method is used, the rotor may become unstable after the rated operating speed, affecting the safety of the test.

[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 the present application, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0008] In view of at least one of the above technical problems, the present application provides a third-order bending critical power turbine rotor test equipment, which can carry out tests by simulating rotors instead of real rotors, greatly shortening the processing cycle, reducing test costs and lowering test 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 device 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, wherein the simulated rotor comprises a rotor shaft, and a disc-shaped power turbine first-stage wheel disk and a power turbine second-stage wheel disk connected to the rotor shaft, wherein the power turbine first-stage wheel disk and the power turbine second-stage wheel disk are used to simulate a real power turbine first-stage blade disk and a power turbine second-stage blade disk in a one-to-one correspondence; The cross-third-order bending critical power turbine rotor test equipment 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 on the test platform at intervals 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.

[0011] 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.

[0012] According to another aspect of the present application, a method for testing a power turbine rotor across a third-order bending criticality is also provided, 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: S100, designing a simulated rotor, wherein the simulated rotor includes a rotor shaft and a simulated wheel disc, wherein the simulated wheel disc includes a first-stage wheel disc of a power turbine and a second-stage wheel disc of a power turbine, and the first-stage wheel disc of the power turbine and the second-stage wheel disc of the power turbine are used to simulate a real first-stage blade disc of a power turbine and a real second-stage blade disc of a power turbine; S200, performing finite element analysis of the strength of a simulated wheel disc to obtain stress distribution of a first-stage wheel disc of a power turbine and a second-stage wheel disc of a power turbine; S300, perform a simulated roulette strength test to verify that if the simulated roulette does not break, the strength meets the requirements; otherwise, adjust the simulated roulette parameters; S400, perform finite element analysis on the dynamic characteristics of the simulated rotor, and obtain the vibration modes of the simulated rotor at the first three critical speeds by calculating with dedicated rotor dynamics software; S500, conduct bearing over-speed endurance test to verify the working reliability of the real bearing assembled on the simulated rotor under the test condition of crossing the third-order critical speed; S600, conduct a simulated rotor cross-third critical speed test verification, and clamp the simulated rotor through the third-order bending critical power turbine rotor test equipment and drive the simulated rotor for testing.

[0013] 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 wheel disc of the power turbine are consistent with those of the actual first-stage blade disc of the power turbine; the material, mass, center of mass, polar moment of inertia and diameter moment of inertia of the second-stage wheel disc of the power turbine are consistent with those of the actual second-stage blade disc of the power turbine.

[0014] In some embodiments of the present application, in step S100, except for the simulated wheel disc, the other parts of the simulated rotor are consistent with the real rotor.

[0015] In some embodiments of the present application, in step S200, stress analysis and calculation are performed on the first-stage impeller and the second-stage impeller of the power turbine 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 impeller and the second-stage impeller of the power turbine are both greater than 1.0, the requirements are met, otherwise the simulation impeller parameters are adjusted.

[0016] In some embodiments of the present application, in step S300, the simulated wheel disc is clamped using an existing vertical wheel disc rotation tester, and the predetermined rotation speed is set to the rotation speed of the blade free fall speed empirical value. 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.

[0017] In some embodiments of the present application, in step S400, the bearing unit in the software is used to simulate the bearings that support 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.

[0018] 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.

[0019] 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 a vibration acceleration sensor is arranged on the front support and the rear support of the support mechanism to measure the vibration acceleration, and the temperature of the bearings on the simulated rotor is measured by a temperature sensor.

[0020] This application has the following beneficial effects: The present invention crosses the third-order bending critical power turbine rotor test equipment to carry out the test by simulating the rotor instead of the real rotor, wherein the simulated rotor adopts the simulated wheel disc, namely the power turbine first wheel disc and the power turbine second wheel disc, and the power turbine first wheel disc and the power turbine second wheel disc are used to simulate the power turbine first blade disc and the power turbine second blade disc respectively, and the simulated rotor, except for the simulated wheel disc, has the same other structures and parts as the real rotor, so the test can be carried out by the simulated rotor, which can greatly shorten the processing cycle, reduce the test cost and reduce 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, and then detect various parameters in the simulated rotor test process through the test system, because there is no need to process the real complete rotor parts, the parts processing cost is effectively reduced, the test cycle is shortened, and the overall test cost is reduced.

[0021] The test method for power turbine rotor across the third-order bending criticality of the present application also has the above-mentioned beneficial effects. It also includes replacing the blade disk with a simulated wheel disk, and obtaining the stress distribution of the first-stage wheel disk of the power turbine and the second-stage wheel disk of the power turbine through finite element analysis. At the same time, the simulated wheel disk is tested and verified, and the strength of the simulated wheel disk outside the rated working speed is verified to meet the requirements; in addition, after the vibration mode of the simulated rotor under the first three critical speeds is calculated by the rotor dynamics special software, the bearing over-rotation and long-term operation test is also carried out to verify the working reliability of the real bearing assembled on the simulated rotor under the third-order critical speed test condition; finally, the simulated rotor is clamped by the power turbine rotor test equipment across the third-order bending criticality and the simulated rotor is driven to perform the test verification across the third-order critical speed. The present 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, the simulated rotor is finally 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 beneficial to improving the accuracy of the test, and promote 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 working reliability of the bearing, and the strength of the wheel, to provide support for the whole-machine containment test of the free fall of the power turbine rotor blades of the civil turboshaft engine.

[0022] Of course, any product implementing this application does not necessarily need to achieve all the advantages described above at the same time. In addition to the purposes, features and advantages described above, this application also has other purposes, features and advantages. The following will further describe this application in detail with reference to the figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 It is a schematic diagram of the overall structure of a power turbine rotor test device across three-order bending criticality according to a preferred embodiment of the present application; Figure 2 is a schematic diagram of a simulated rotor of a preferred embodiment of the present application installed on a power turbine rotor test device across a third-order bending criticality; Figure 3 is an overall schematic diagram of a simulated rotor of a preferred embodiment of the present application; Figure 4 This is a schematic diagram of the structure 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 in a preferred embodiment of the present application; Figure 6 It is a schematic diagram of stress distribution of a first-stage disk of a power turbine in a preferred embodiment of the present application; Figure 7 It 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; Fig. 9 It is a 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; Fig.10 It is a 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; Fig.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; Fig.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; Fig.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; Fig.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; Fig.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 sustained operation test.

[0024] Legend: 100, simulated rotor; 101, rotor shaft; 102, first-stage impeller of power turbine; 103, second-stage impeller of power turbine; 1, power mechanism; 2, transmission mechanism; 3, supporting 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

[0025] The embodiments of the present application are described in detail below in conjunction with the accompanying drawings, but the present application can be implemented in a variety of different ways defined and covered below.

[0026] Figure 1 It is a schematic diagram of the overall structure of a power turbine rotor test device across three-order bending criticality according to a preferred embodiment of the present application; Figure 2 is a schematic diagram of a simulated rotor of a preferred embodiment of the present application installed on a power turbine rotor test device across a third-order bending criticality; Figure 3 is an overall schematic diagram of a simulated rotor of a preferred embodiment of the present application; Figure 4 This is a schematic diagram of the structure 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 in a preferred embodiment of the present application; Figure 6 It is a schematic diagram of stress distribution of a first-stage disk of a power turbine in a preferred embodiment of the present application; Figure 7 It 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; Fig. 9 It is a 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; Fig.10 It is a 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; Fig.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; Fig.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; Fig.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; Fig.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; Fig.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 sustained operation test.

[0027] A three-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 three-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 wheel disc 102 and a power turbine second-stage wheel disc 103 connected to the rotor shaft 101 and connected to each other. The power turbine first-stage wheel disc 102 and the power turbine second-stage wheel disc 103 are used to simulate a real power turbine first-stage blade disc and a power turbine second-stage blade disc in a one-to-one correspondence. The cross-third-order bending critical power turbine rotor test equipment also includes a vacuum mechanism 5. 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 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.

[0028] 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. The simulated wheel includes a power turbine first-stage wheel 102 and a power turbine second-stage wheel 103 .

[0029] In actual design, the simulated wheel disc is an axisymmetric multi-stage wheel disc structure as a whole. The wheel disc does not need to be processed into a blade shape. It can play an effective substitution role by ensuring that the mass, center of mass, polar moment of inertia and diameter moment of inertia of the simulated wheel disc and the real blade disc are consistent, and the material of the simulated wheel disc is consistent with the real blade disc. The simulated wheel disc is then subjected to strength analysis and test verification to ensure that the wheel disc strength meets the requirements.

[0030] When in use, the rotor shaft 101 is clamped by the front support 32 and the rear support 33, the power mechanism 1 can be connected to the rotor shaft 101 through the transmission mechanism 2, and the simulated rotor 100 is driven to rotate by the power mechanism 1 to carry out the test, and various test parameters are monitored and collected by the test system 7.

[0031] The present invention crosses the third-order bending critical power turbine rotor test equipment to carry out the test by simulating the rotor 100 instead of the real rotor, wherein the simulated rotor 100 adopts a simulated wheel, namely the power turbine first-stage wheel 102 and the 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 the power turbine first-stage blade disk and the power turbine second-stage blade disk respectively, and the simulated rotor 100, except for the simulated wheel, has the same other structures and parts as the real rotor, so the test can be carried out by the simulated rotor 100, which greatly shortens the processing cycle, reduces the test cost and reduces the test risk. The support mechanism 3 can clamp and support the simulated rotor 100, drive the simulated rotor 100 to rotate through the power mechanism 1, provide lubricating oil to the simulated rotor 100 through the lubricating oil mechanism 4, and realize the simulated rotor 100 vacuum operation test environment by vacuuming through the vacuum mechanism, and then detect various parameters of the simulated rotor 100 during the test process through the test system 7, because there is no need to process the real complete rotor parts, the parts processing cost is effectively reduced, the test cycle is shortened, and the overall test cost is reduced.

[0032] Preferably, please refer to Figure 1 As shown, the third-order bending critical power turbine rotor test equipment also includes an explosion-proof chamber 8 , which is used to shield and protect the supporting mechanism 3 and the simulated rotor 100 .

[0033] It is understandable that, since the test speed of the cross-third-order bending critical speed test exceeds the rated operating speed of the simulated rotor 100, the test equipment of the present application is equipped with an explosion-proof chamber 8 to play an explosion-proof role, 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 stopped in an emergency when abnormal conditions such as test failures occur. At the same time, the test system 7 of the test equipment of the present application also includes monitoring sensors such as speed, temperature, oil supply pressure, and vibration, to realize various over-limit alarm functions, so as to monitor various test parameters in real time and ensure the safety of the test.

[0034] 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, and the method for testing a power turbine rotor across a third-order bending criticality includes the following steps: S100, designing a simulated rotor 100, wherein the simulated rotor 100 includes a rotor shaft 101 and a simulated wheel disc, wherein the simulated wheel disc includes a power turbine first-stage wheel disc 102 and a power turbine second-stage wheel disc 103, and the power turbine first-stage wheel disc 102 and the power turbine second-stage wheel disc 103 are used to simulate a real power turbine first-stage blade disc and a power turbine second-stage blade disc; 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; S300, perform a simulated roulette strength test to verify that if the simulated roulette does not break, the strength meets the requirements; otherwise, adjust the simulated roulette parameters; S400, performing finite element analysis of dynamic characteristics of the simulated rotor 100, and calculating and obtaining vibration modes of the simulated rotor 100 at the first three critical speeds by using rotor dynamics dedicated software, such as SAMCEF / ROTOR; 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 a third-order critical speed; S600, conducting a test run verification of the simulated rotor 100 across the third-order critical speed, by clamping the simulated rotor 100 through a third-order bending critical power turbine rotor test device and driving the simulated rotor 100 for testing.

[0035] This application aims to solve the technical difficulties of power turbine rotor testing across the third-order bending critical speed, and proposes a power turbine rotor testing equipment and testing method across the third-order bending critical speed. The specific testing process, steps and implementation method of the power turbine rotor 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, and at the same time solves the technical difficulties of power turbine rotor testing across the bending critical speed outside the rated working speed. Through this application, the third-order bending critical speed test of a power turbine rotor of a civil turboshaft engine was successfully completed, providing support for the whole machine containment test of the free shedding of the blades of the power turbine rotor of the civil turboshaft engine.

[0036] The present invention relates to a power turbine rotor test method that crosses the third-order bending criticality by replacing the blade disk with a simulated disk, and obtains the stress distribution of the first-stage disk 102 of the power turbine and the second-stage disk 103 of the power turbine through finite element analysis. At the same time, the simulated disk is subjected to a test run for verification, and it is verified that the strength of the simulated disk meets the requirements outside the rated working speed. 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 sustained operation test is also carried out to verify the working reliability of the real bearing assembled on the simulated rotor 100 under the third-order critical speed test condition. Finally, the simulated rotor 100 is clamped by the power turbine rotor test equipment that crosses the third-order bending criticality and driven to perform a test run for verification across the third-order critical speed. The present 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, the simulated rotor 100 is finally 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 test across the third-order critical speed of the simulated rotor 100, which is beneficial to improving the accuracy of the test, and promote the efficient completion of the power turbine rotor across the third-order bending critical speed test, and comprehensively consider and verify the dynamic characteristics outside the rated operating speed, the working reliability of the bearing, and the strength of the wheel, so as to provide support for the whole-machine containment test of the free fall of the power turbine rotor blades of the civil turboshaft engine.

[0037] Preferably, in step S100, the power turbine first-stage impeller 102 is consistent with the material, mass, center of mass, polar moment of inertia and diameter moment of inertia of the actual power turbine first-stage blade disk; the power turbine second-stage impeller 103 is consistent with the material, mass, center of mass, polar moment of inertia and diameter moment of inertia of the actual power turbine second-stage blade disk.

[0038] In this preferred embodiment, except for the simulated wheel disc, the other parts of the simulated rotor 100 are consistent with the real rotor.

[0039] It is understandable that in order to avoid the high risk, high cost, long processing cycle and other problems brought by directly using the real rotor test, the simulated rotor 100 is designed. In order to perform simulated wheel strength analysis and test verification so that the wheel strength meets the requirements, the simulated wheel is made of the same material as the real blade disk, and the key parameters of the simulated wheel are adjusted to a small error with the blade disk to ensure the effectiveness of the test.

[0040] In some embodiments, the structure of the simulated roulette wheel is as follows Figure 4 As shown, it is a multi-stage wheel disc structure, and there is no need to process the shape of the blades, in which the power turbine first-stage wheel disc 102 and the power turbine second-stage wheel disc 103 are connected to each other. The quality characteristics of the simulated wheel disc and the real wheel disc are compared in the following table: Table 1 is a comparison of the quality characteristics of the simulated wheel and the real blade disk

[0041] 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 by 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 the 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.

[0042] It is understandable that the finite element analysis can be used to preliminarily determine whether the strength of the simulated wheel meets the test requirements. The stress distribution of the first-stage wheel 102 and the second-stage wheel 103 of the simulated wheel can be determined by referring to Figure 6 and Figure 7 , which can efficiently identify weak links and facilitate targeted strengthening design.

[0043] It should be noted that the temperature load in the calculation in step S200 is room temperature (because the test run is usually carried out at room temperature), and a binding contact is established at the connection position between the first-stage power turbine wheel 102 and the second-stage power turbine wheel 103. The established finite element mesh is shown in FIG. Figure 5 As shown, the conventional method of applying centrifugal load at a rotation speed (about 32000r / min in some embodiments) is adopted, and the stress distribution of the simulated wheel disk can be calculated by using common finite element software.

[0044] Preferably, in step S300, the simulated wheel disc is clamped using an existing vertical wheel disc 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 disc vibrates stably and does not break, it indicates that the strength of the simulated wheel disc meets the requirements.

[0045] It is understandable that by setting a predetermined speed (about 32000r / min in some embodiments) as the empirical value of the free falling speed of the blades, it is possible to verify whether the strength of the simulated wheel disk meets the requirements through actual test runs. If cracking or other phenomena occur, targeted structural optimization can be performed in combination with the finite element analysis results.

[0046] Preferably, in step S400, the bearing unit in the software simulates the bearings that support the real rotor, and calculates the vibration mode 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.

[0047] It is understandable that by analyzing and simulating the dynamic characteristics of the rotor 100 in advance through the rotor dynamics dedicated software, the critical speed, vibration mode distribution and the third-order critical speed value of the rotor outside the rated working speed can be known in advance. Fig. 9 , Fig.10 and Fig.11 , respectively, are the vibration modes of the simulated rotor 100 at the third-order critical speed, indicating 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.

[0048] 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.

[0049] In this preferred embodiment, the speed of the bearing overspeed endurance test also covers the blade free fall experience speed, and a margin of about 10% can be left to ensure the safety of the test. The working reliability of the bearing in the third-order critical speed test can be verified through the bearing overspeed endurance test.

[0050] In some embodiments, 1#, 2#, 5# and 6# bearings consistent with the whole machine are selected to carry out bearing over-rotation endurance operation tests respectively. The endurance operation test results of each bearing are shown in the following table: Table 2 is the table of bearing over-speed endurance test results Bearings Test situation 1# bearing The blades were running at the free falling speed for more than 60 minutes, and the bearing temperature was stable at about 168°C. After the test, the bearing was in good condition, and there was no damage to the inner and outer rings, cages, and rolling elements of the bearing; the bearing rotated flexibly without any obstruction. 2# bearing The bearing ran continuously for about 4 hours at the blade free-falling speed, with the highest bearing temperature of about 125°C. The bearing temperature was stable during the test, and there was no blocking phenomenon in the bearing after the test. 5# bearing The test bearing was operated continuously for 50 hours at the blade free falling speed and rotated flexibly. 6# bearing After running continuously for 50 hours at the blade free falling speed, the maximum bearing temperature is about 165℃. After the test, the bearing rotates flexibly. Please refer to the photos of each bearing after the test Figure 12-15 ,From the bearing endurance operation test results, it can be known 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, which meets the test requirements of the simulated rotor crossing the third order critical speed.

[0051] 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 a vibration acceleration sensor is 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.

[0052] 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 simulated rotor 100 cross-third critical speed test verification, a displacement sensor is arranged on the rotor shaft 101 of the simulated rotor 100. Specifically, four displacement sensors (D1-D4) can be arranged to measure the vibration displacement of the rotor shaft 101 during the test; at the same time, A1 and A2 vibration acceleration sensors are respectively installed on the front support 32, and A3 and A4 vibration acceleration sensors are respectively installed on the rear support 33 to measure the vibration acceleration; and the temperature of each bearing is measured by the thermocouples T1-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-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.

[0053] 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 disc, a method for endurance operation of an external bearing at a rated operating speed, and a method for testing a third-order bending critical speed.

[0054] This application uses a simulated rotor 100 to replace the real rotor for testing, which greatly shortens the processing cycle, reduces the test cost and reduces the test risk. The design error between the simulated wheel and the real wheel is very small, and the test can be replaced in structure, and it is verified that the strength of the outer wheel at the rated working speed meets the requirements. The reliability of the bearing's long-term operation at the blade free fall speed is verified. A method for implementing the rotor cross-third-order bending critical speed test is provided to verify the correctness of the method.

[0055] The technical solution of this application was used to complete the third-order bending critical speed test for a civil turboshaft engine power turbine rotor, and the distribution of the third-order critical speed outside the rated operating speed was obtained. The rotor smoothly passed the third-order bending critical and the vibration was stable. Based on the test results of the simulated rotor 100, the same method was used to complete the real rotor third-order bending critical speed test, laying a solid foundation for the whole machine containment test of blade free shedding.

[0056] 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 other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0057] 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 its 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 and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of this application, 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 the protection of this application.

Claims

1. A third-order bending critical power turbine rotor test device, comprising a support mechanism (3) for supporting a 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), characterized in that: The simulated rotor (100) comprises 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, wherein 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; 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 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), and the rotor shaft (101) is connected to the power mechanism (1).

2. The three-order bending critical power turbine rotor test equipment according to claim 1 is characterized in that: The third-order bending critical power turbine rotor test equipment also includes an explosion-proof chamber (8), which is used to shield and protect the support mechanism (3) and the simulated rotor (100).

3. A method for testing a power turbine rotor across a third-order bending criticality, characterized in that: Using the three-stage bending critical power turbine rotor test equipment as described in any one of claims 1-2, the three-stage bending critical power turbine rotor test method includes the following steps: S100, designing a simulated rotor (100), wherein the simulated rotor (100) comprises a rotor shaft (101) and a simulated wheel, and the simulated wheel comprises a first-stage wheel (102) of a power turbine and a second-stage wheel (103) of a power turbine; S200, performing a simulated wheel disc strength finite element analysis to obtain stress distribution of a first-stage wheel disc (102) of a power turbine and a second-stage wheel disc (103) of a power turbine; S300, perform a simulated roulette strength test to verify that if the simulated roulette does not break, the strength meets the requirements; otherwise, adjust the simulated roulette parameters; S400, performing 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 dedicated software; 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 a third-order critical speed; S600, conducting a simulated rotor (100) cross-third critical speed test verification, by clamping the simulated rotor (100) through a cross-third bending critical power turbine rotor test device and driving the simulated rotor (100) for testing.

4. The method for testing a power turbine rotor across a third-order bending criticality according to claim 3, characterized in that: In step S100, the material, mass, center of mass, polar moment of inertia and diameter moment of inertia of the first-stage wheel disk (102) of the power turbine are consistent with those of the actual first-stage blade disk of the power turbine; 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.

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

6. The method for testing a power turbine rotor across a third-order bending criticality according to claim 3, characterized in that: In step S200, stress analysis calculation is 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 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 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 simulated wheel parameters are adjusted.

7. The method for testing a power turbine rotor across third-order bending criticality according to claim 3, characterized in that: In step S300, the simulated wheel disc is clamped using an existing vertical wheel disc rotation tester, and the predetermined rotation speed is set to the rotation speed of the blade free fall speed experience value. 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.

8. The method for testing a power turbine rotor across third-order bending criticality according to claim 3, characterized in that: In step S400, a bearing unit in the software is used to simulate a bearing supporting a real rotor, and the vibration mode of the simulated rotor (100) at a first-order critical speed of 0.39 times the rated operating speed, a second-order critical speed of 0.7 times the rated operating speed, and a third-order critical speed of 1.51 times the rated operating speed is calculated.

9. The method for testing a power turbine rotor across third-order bending criticality according to claim 3, characterized in that: 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.

10. The method for testing a power turbine rotor across third-order bending criticality according to claim 3, 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.

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