Aero-engine vibration examination test method and system

Abstract

This invention belongs to the field of aero-engine vibration testing technology, and specifically relates to a method and system for aero-engine vibration assessment testing; it includes: determining the most severe vibration environment for the components; determining the engine rotor dwell speed and dwell time at the dwell speed; formulating a vibration assessment test spectrum based on the engine rotor dwell speed and dwell time; conducting a whole-engine test based on the most severe vibration environment for the components and referring to the vibration assessment test spectrum; generating an engine speed versus vibration curve based on the engine whole-engine test measurement data, and formulating component vibration limit values; conducting the component vibration assessment test on the whole engine, and the whole engine used for the component vibration assessment test simulates the maximum possible vibration environment and test temperature of the components across the entire operating cycle and speed range; making the installation and vibration environment more consistent with actual engineering conditions.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine vibration testing technology, and specifically relates to a method and system for aero-engine vibration assessment testing. Background Technology

[0002] Accessories are generally installed on the casing of aircraft engines. In actual operation, they are affected by various vibration loads caused by engine rotor excitation and vibration of their own rotating parts. In order to ensure that the accessories will not suffer structural damage due to vibration during long-term use and can perform stably in different vibration environments, vibration test is required for each type of accessory.

[0003] The existing vibration test method for accessories is as follows: First, an environmental vibration spectrum is formulated with reference to GJB150.16 or DO-160. This vibration spectrum specifies the vibration pattern, frequency range, and vibration amplitude. Then, the accessories are installed on a vibration table and the formulated environmental vibration spectrum is applied through the vibration table. Finally, according to the life requirements of the accessories (currently, the life of engines is generally less than 1000 hours, and the requirements for accessories are higher), a vibration test is carried out in each of the three directions (horizontal, vertical, and axial) for at least 30 minutes, with a cumulative duration of not less than 3 hours.

[0004] The existing vibration testing methods for engine components have the following drawbacks:

[0005] 1) The environmental vibration spectrum of each type of accessory is the same, which leads to some accessories being tested too leniently or too strictly. In reality, the environmental vibration spectrum of each type of accessory will inevitably be different due to factors such as different installation positions in the engine casing and different masses.

[0006] 2) The test process is generally carried out at room temperature, which cannot take into account the influence of temperature factors. In actual work, the temperature at the installation location of some components is above 300℃. High temperature has a significant impact on the stiffness, fatigue and other characteristics of the components. The existing test results cannot completely prove that damage will not occur in actual work.

[0007] 3) The test time is too long. Engine components are generally around type 40, so the cumulative test time will be no less than 120 hours. Summary of the Invention

[0008] To address the above problems, this invention proposes a vibration testing method for aero-engines, comprising:

[0009] The assembly of the engine unit for vibration testing of the components was completed based on the most severe vibration environment of the components.

[0010] Determine the engine rotor dwell speed and dwell time at that speed;

[0011] Based on the engine rotor dwell speed and dwell time at the dwell speed, a vibration test test pattern is formulated;

[0012] The engine was tested in accordance with the vibration test test spectrum.

[0013] Furthermore, the worst vibration environment for the attached components includes:

[0014] Set the worst-case imbalance of the engine rotor;

[0015] Based on the level of the balance accuracy standard, the worst imbalance of the rotating parts of the accessory itself is set.

[0016] Furthermore, determining the engine rotor dwell speed specifically includes:

[0017] The minimum steady-state speed of the rotor is obtained from the engine limit value file. The maximum steady-state speed is The maximum transient speed is The systematic error of rotor speed control is and rotor overshoot ;

[0018] according to , , , and To obtain the minimum rotor speed is and maximum speed is ;

[0019] according to and To obtain the engine rotor dwell speed.

[0020] Furthermore, the dwell time for determining the dwell speed specifically includes: based on the known engine rotor dwell speed being greater than 10 and the number of vibration dwell times of the assembly being no less than 107; it is concluded that the number of vibration dwell times of the assembly at each engine rotor dwell speed is no less than 106.

[0021] The dwell time at the dwell speed is obtained by considering the engine rotor dwell speed and the number of vibration dwell times at the dwell speed.

[0022] Furthermore, the engine whole-machine test was completed;

[0023] Based on the engine whole machine test measurement data, an engine speed and vibration curve is generated, and the vibration limit value is formulated as an accessory.

[0024] In accordance with the quality inspection standards for accessories, the accessories are disassembled and inspected.

[0025] Furthermore, the aforementioned vibration limit values ​​specifically include: engine body vibration values ​​at various stationary speeds, based on engine whole-machine test measurement data. ;Will Sort the engine body vibration values ​​from largest to smallest, and record the top K values ​​as follows: Where K represents the number of engine body vibration values ​​selected from largest to smallest; then the vibration margin is calculated according to formula (1). ;

[0026] (1)

[0027] The vibration limit value V of the accessory is calculated according to formula (2);

[0028] (2).

[0029] Furthermore, the aforementioned according to , , , and Obtain the minimum rotor speed and maximum speed Specifically,

[0030] Calculate the minimum rotor speed according to formula (3). ;

[0031] (3)

[0032] Calculate the maximum rotor speed according to formula (4). ;

[0033] (4).

[0034] Furthermore, the aforementioned according to and To obtain the engine rotor dwell speed, specifically...

[0035] like Then, according to formula (5), the dwell speed of the i-th engine rotor can be obtained. The speed increment is 120 rpm.

[0036] (5)

[0037] in Rated speed is the rated speed;

[0038] like Then, according to formula (6), the dwell speed of the i-th engine rotor can be obtained. Speed ​​steps according to ;

[0039] (6).

[0040] Furthermore, the dwell time at each dwell speed is obtained based on the engine rotor dwell speed and the number of vibration dwell times at that dwell speed. Specifically, it includes:

[0041] The dwell time corresponding to the dwell speed is obtained according to formula (7). ; (7)

[0042] The total cumulative stay time is obtained according to formula (8). ;

[0043] (8).

[0044] This invention proposes a vibration testing system for aero-engines, the system comprising:

[0045] The engine assembly meets the most severe vibration environment requirements for component vibration testing.

[0046] A control device connected to the engine unit, used to control the rotational speed of the engine rotor and calculate the dwell speed and dwell time of the engine rotor.

[0047] Vibration test spectrum generated by the control device;

[0048] The test apparatus is used to input the vibration test spectrum and to conduct engine whole-machine tests.

[0049] Beneficial effects

[0050] The advantages of this invention over the prior art are as follows:

[0051] 1. This application conducts the vibration test of the accessories on the engine as a whole, and the engine used for the vibration test of the accessories simulates the maximum possible vibration environment and test temperature of the accessories in the whole operating cycle and the whole speed range; thus making the installation and vibration environment more in line with the actual engineering situation.

[0052] 2. This application shortens the testing time by placing the complete accessories in the whole machine for testing, which can reduce the testing time by 40-50% and further accelerate the testing progress.

[0053] 3. This application obtains vibration margin and vibration limit values ​​by measuring the vibration data of the engine body in the test, establishes the relationship between the vibration of the engine body and the vibration of the accessories, and formulates vibration limit values ​​for the field monitoring of the accessories, thereby further ensuring the safe use of the engine.

[0054] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 A flowchart of a method according to an embodiment of the present invention is shown.

[0057] Figure 2 A flowchart of the experiment in an embodiment of the present invention is shown.

[0058] Figure 3 The attached resonance response diagram of an embodiment of the present invention is shown.

[0059] Figure 4 A schematic diagram of the test run spectrum of the engine rotor dwell speed under no dwell time limitation is shown in an embodiment of the present invention.

[0060] Figure 5 This diagram illustrates a test run spectrum of the engine rotor dwell speed under a dwell time limitation in an embodiment of the present invention.

[0061] Figure 6 A flowchart illustrating the determination of external vibration limit values ​​in an embodiment of the present invention is shown. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] This application provides a vibration assessment test method for an aero-engine, referencing... Figure 1 and Figure 2 ,include:

[0064] The assembly of the engine unit for vibration testing of the components was completed based on the most severe vibration environment of the components.

[0065] Determine the engine rotor dwell speed and dwell time at that speed;

[0066] Based on the engine rotor dwell speed and dwell time at the dwell speed, a vibration test test pattern is formulated;

[0067] The engine was tested in accordance with the vibration test test spectrum.

[0068] In one embodiment of the present invention, the worst vibration environment for the assembly includes:

[0069] Set the worst-case imbalance of the engine rotor;

[0070] Based on the level of the balance accuracy standard, the worst imbalance of the rotating parts of the accessory itself is set.

[0071] In one embodiment of the present invention, after the engine whole-machine test is completed;

[0072] Based on the engine whole-machine test measurement data, the engine speed and vibration curve is generated, and the vibration limit value of the accessories is formulated; the fatigue damage of accessories is accelerated by the cumulative effect of vibration energy, and the equivalent field service conditions are verified in the laboratory.

[0073] In accordance with the quality inspection standards for accessories, the accessories are disassembled and inspected.

[0074] After the test, the components are disassembled according to the component quality inspection standards, and the functions of each component are checked to determine whether the components are functioning normally. If all components are disassembled and checked and found to be functioning normally, then the vibration fatigue characteristics of the components are considered to meet the usage requirements within the above-mentioned vibration limit values. Conversely, if any component is disassembled and checked and found to be functioning abnormally, then the vibration fatigue characteristics of the components are considered to not meet the usage requirements within the above-mentioned vibration limit values.

[0075] During implementation, the components are mainly subjected to vibration loads caused by engine rotor excitation and vibration of their own rotating parts. These vibration loads are mainly caused by rotor imbalance. Therefore, to simulate the worst vibration environment of the components, it is necessary to adjust the engine rotor imbalance and the component's own rotating parts imbalance to the worst possible state. For the worst-case engine rotor imbalance, the patent "Method and System for Determining Maximum Imbalance of Engine Rotor, Electronic Equipment, and Storage Medium" can be used for pre-design. For the worst-case imbalance of the component's own rotating parts, the factory imbalance is generally controlled according to the G0.4 accuracy level in the international balance accuracy standard ISO1940. However, in actual operation, wear of rotating parts will lead to an increase in imbalance. Considering that the structure of the component's own rotating parts is relatively simple and the operating conditions are relatively stable, the worst-case imbalance of the component's own rotating parts can be reduced by one accuracy level from the factory balance accuracy level, that is, pre-designed according to the G1.0 accuracy level.

[0076] As required, the unbalance of the engine rotor and the rotating parts of the accessories was prefabricated, and the assembly of the engine for vibration testing of the accessories was completed in accordance with the assembly process.

[0077] The vibration environment of the assembly is related not only to the unbalance but also to the rotor speed. Therefore, by determining the engine rotor dwell speed and the dwell time at the engine rotor dwell speed, a test spectrum for the vibration of the assembly under the condition of the whole machine is formulated. Based on the assembled engine machine completed according to the assembly process, the vibration test of the assembly is carried out. In the vibration test, the vibration of the engine body at each engine rotor dwell speed is measured, the engine speed and vibration curve are obtained, and the relationship between the vibration of the engine body and the vibration of the assembly is established.

[0078] This application conducts the vibration test of the accessories on the entire engine, and the engine used for the vibration test of the accessories simulates the maximum possible vibration environment and test temperature of the accessories throughout the entire operating cycle and speed range; thus making the installation and vibration environment more in line with the actual engineering situation.

[0079] In one embodiment of the present invention, determining the engine rotor dwell speed specifically includes:

[0080] The minimum steady-state speed of the rotor is obtained from the engine limit value file. The maximum steady-state speed is The maximum transient speed is The systematic error of rotor speed control is and rotor overshoot ;

[0081] according to , , , and To obtain the minimum rotor speed is and maximum speed is ;

[0082] according to and To obtain the engine rotor dwell speed.

[0083] In one embodiment of the present invention, the dwell time for determining the dwell speed specifically includes: based on the known engine rotor dwell speed being greater than 10 and the number of vibration dwell times of the assembly being not less than 107; it is concluded that the number of vibration dwell times of the assembly at each engine rotor dwell speed is not less than 106.

[0084] The dwell time at the dwell speed is obtained by considering the engine rotor dwell speed and the number of vibration dwell times at the dwell speed.

[0085] Based on the equivalent relationship calculated using Miner's fatigue cumulative damage theory, it is concluded that the vibration dwell time of the attachment is no less than 107 times.

[0086] In one embodiment of the present invention, the method according to , , , and Obtain the minimum rotor speed and maximum speed Specifically,

[0087] Calculate the minimum rotor speed according to formula (3). ;

[0088] (3)

[0089] Calculate the maximum rotor speed according to formula (4). ;

[0090] (4).

[0091] In one embodiment of the present invention, reference is made to Figure 2 , Figure 3 , Figure 4 and Figure 5 According to and To obtain the engine rotor dwell speed, specifically...

[0092] like Then, according to formula (5), the dwell speed of the i-th engine rotor can be obtained. The speed increment is 120 rpm.

[0093] (5)

[0094] in Rated speed is the rated speed;

[0095] like Then, according to formula (6), the dwell speed of the i-th engine rotor can be obtained. Speed ​​steps according to ;

[0096] (6).

[0097] When the assembly is in resonance at a certain speed, insufficient speed control precision will prevent it from maintaining resonance for an extended period, leading to a loose test result. Therefore, during testing, high-precision speed control equipment must be used to control the rotor speed. Based on the component resonance curves and engineering experience, the required speed control precision is within 60 rpm. Therefore, if... Rotor dwell speed during vibration test of components The speed can be increased in 120 rpm increments, starting from the minimum speed. Climb to maximum speed ;

[0098] like , ×45000, ×45000;

[0099] Therefore, the total rotational speed required to stop is (1.02-0.8)×45000 / 120=82.5, which rounds up to 83, greater than 9. =83, plus 1 at the rear boundary, for a total of 84 dwell times.

[0100] ; ; ……, ; ;

[0101] like In the vibration test of the components, the rotor dwell speed can be determined according to... The speed step, from the minimum speed Climb to maximum speed ;

[0102] like , ×45000, ×45000;

[0103] Therefore, the total rotational speed required to stop is (1.02-1.0)×45000 / 120=7.5, which is rounded up to 8, less than 9. At this point, the rotational speed step is... .

[0104] ; ; ……, ; ;

[0105] In one embodiment of the present invention, the dwell time at each dwell speed is obtained based on the engine rotor dwell speed and the number of vibration dwell times at that dwell speed. Specifically, it includes:

[0106] The dwell time corresponding to the dwell speed is obtained according to formula (7). ; (7)

[0107] The total cumulative stay time is obtained according to formula (8). ;

[0108] (8).

[0109] During implementation, taking a certain type of engine as an example, its minimum rotor speed is 28350 rpm and its maximum speed is 46350 rpm. The cumulative total time is calculated based on equations (7) and (8). The test duration is 68.75 hours, while this type of engine has a total of 43 types of accessories. According to the existing test methods, the total cumulative time is no less than 129 hours, which can shorten the test time by 40%-50%.

[0110] In addition, since the rotor dwell speed in the vibration test of the accessories has reached the limit value and the dwell time is more than 20 minutes, but in actual use, the time for the engine to dwell at the limit speed is strictly limited to ensure safety. Therefore, when the dwell speed is above the speed at which the engine is limited in terms of usage time, the dwell time at that dwell speed needs to be split. However, the total time accumulated after splitting must meet the original dwell time requirement.

[0111] Taking a certain type of engine as an example, the engine rotor cannot stay for more than 2 minutes at a speed of 45450 rpm. For a speed greater than 45450 rpm, such as 45510 rpm, the dwell time should be no less than 22 minutes. Therefore, the 22 minutes need to be divided into 11 parts. After running one part, the engine speed is reduced to a low speed and there is no limit to the duration of a single run. This process is repeated until all 11 parts have been tested.

[0112] In one embodiment of the present invention, reference is made to Figure 6 The vibration limit values ​​specified in the appendix specifically include: engine body vibration values ​​at various stationary speeds, based on the engine whole-machine test measurement data. ;Will Sort the engine body vibration values ​​from largest to smallest, and record the top K values ​​as follows: Where K represents the number of engine body vibration values ​​selected from largest to smallest; then the vibration margin is calculated according to formula (1). ;

[0113] (1)

[0114] The vibration limit value V of the accessory is calculated according to formula (2);

[0115] (2).

[0116] Existing vibration assessment tests for engine components cannot provide a reference for monitoring the field use of components. Field use of engines typically involves real-time vibration monitoring of the engine body, but current vibration assessment tests for components are conducted on a component test bench and are pass / fail tests, making it impossible to establish a relationship between engine body vibration and component vibration.

[0117] Vibration testing of components was conducted by establishing a test run pattern for component vibration assessment under complete machine conditions, based on the determined engine rotor dwell speed and dwell time at each dwell speed. During the test, the engine body vibration was measured at each dwell speed, and the engine body vibration value at each dwell speed was recorded as follows: The measured engine vibration values ​​at each stationary speed were arranged in descending order of magnitude, and the 10 largest engine vibration values ​​were selected and recorded as follows: Following the linear equivalence method, the vibration cycle number of the accessory with the smaller engine body vibration value is converted to the vibration cycle number of the engine body with the maximum vibration value, and the vibration margin is obtained by referring to formula (1). Finally, the vibration limit value of the components is obtained according to formula (2); by establishing the relationship between the vibration of the engine body and the vibration of the components, and formulating the vibration limit value for the external monitoring of the components, the safety of engine use is further guaranteed.

[0118] exist The vibration margin is calculated using formula (1) from ten values: 30, 31, 32, ..., 38, 39. 0.885, then obtain the result according to formula (2). 34.5.

[0119] A vibration testing system for an aero-engine, the system comprising:

[0120] The engine assembly meets the most severe vibration environment requirements for component vibration testing.

[0121] A control device connected to the engine unit, used to control the rotational speed of the engine rotor and calculate the dwell speed and dwell time of the engine rotor.

[0122] Vibration test spectrum generated by the control device;

[0123] The test apparatus is used to input the vibration test spectrum and to conduct engine whole-machine tests.

[0124] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vibration testing method for an aero-engine, characterized in that, include: The assembly of the engine unit for vibration testing of the components was completed based on the most severe vibration environment of the components. Determine the engine rotor dwell speed and dwell time at that speed; Based on the engine rotor dwell speed and dwell time at the dwell speed, a vibration test test pattern is formulated; The engine whole-machine test was carried out in accordance with the vibration test test spectrum described above; The assembly of the engine unit for vibration testing of its components was completed based on the most severe vibration environment of the components, including: Set the worst-case imbalance of the engine rotor; Based on the level of the balance accuracy standard, the worst imbalance of the rotating parts of the accessory itself is set. Determining the engine rotor dwell speed specifically includes: The minimum steady-state speed of the rotor is obtained from the engine limit value file. The maximum steady-state speed is The maximum transient speed is The systematic error of rotor speed control is and rotor overshoot ; according to , , , and To obtain the minimum rotor speed is and maximum speed is ; according to and To obtain the engine rotor dwell speed; According to , , , and Obtain the minimum rotor speed and maximum speed Specifically, Calculate the minimum rotor speed according to formula (3). ; （3） Calculate the maximum rotor speed according to formula (4). ; （4）； According to and To obtain the engine rotor dwell speed, specifically... like Then, according to formula (5), the dwell speed of the i-th engine rotor can be obtained. The speed increment is 120 rpm. （5） in 额定 For the quota rotation speed; like Then, according to formula (6), the dwell speed of the i-th engine rotor can be obtained. Speed ​​steps according to ; （6）； The dwell time at each dwell speed is obtained based on the engine rotor dwell speed and the number of vibration dwell times at that dwell speed. Specifically, it includes: The dwell time corresponding to the dwell speed is obtained according to formula (7). ; (7) The total cumulative stay time is obtained according to formula (8). ; （8）。 2. The vibration testing method for an aero-engine according to claim 1, characterized in that, The dwell time for determining the dwell speed specifically includes: based on the known engine rotor dwell speed being greater than 10 and the number of vibration dwell times of the attachments being no less than 10. 7 The number of vibration dwell times at each engine rotor residence speed was determined to be no less than 10. 6 Second-rate; The dwell time at the dwell speed is obtained by considering the engine rotor dwell speed and the number of vibration dwell times at the dwell speed.

3. The vibration testing method for an aero-engine according to claim 1, characterized in that, After the engine test is completed, based on the engine test measurement data, an engine speed and vibration curve is generated, and vibration limit values ​​are set as an attachment. In accordance with the quality inspection standards for accessories, the accessories are disassembled and inspected.

4. The vibration testing method for an aero-engine according to claim 3, characterized in that, The vibration limit values ​​specified in the appendix specifically include: engine body vibration values ​​at various stationary speeds, based on engine whole-machine test measurement data. ;Will Sort the engine body vibration values ​​from largest to smallest, and record the top K values ​​as follows: Where K represents the number of engine body vibration values ​​selected from largest to smallest; then the vibration margin is calculated according to formula (1). ; （1） The vibration limit value V of the accessory is calculated according to formula (2). 限制值 ; （2）。 5. A test system for implementing the vibration assessment test method for an aero-engine as described in any one of claims 1-4, characterized in that, The system includes: The engine assembly meets the most severe vibration environment requirements for component vibration testing. A control device connected to the engine unit, used to control the rotational speed of the engine rotor and calculate the dwell speed and dwell time of the engine rotor. Vibration test spectrum generated by the control device; The test apparatus is used to input the vibration test spectrum and to conduct engine whole-machine tests.

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