Aero-engine outfield vibration characteristic monitoring and fault diagnosis method

Abstract

The invention belongs to the field of fault diagnosis, and particularly relates to an aero-engine outfield vibration characteristic monitoring and fault diagnosis method, which comprises the following steps: carrying out vibration comparison through engine flight historical data to obtain high-low pressure relative rotation speed in the historical data, and then calculating a vibration average value; obtaining a change curve of the vibration average value along with the rotating speed under the high-pressure relative rotating speed and the low-pressure relative rotating speed; analyzing the vibration characteristic curves of the high-pressure rotor and the low-pressure rotor, and finding out the rotating speed corresponding to the maximum vibration value; and finally, analyzing the change and development trend of the maximum vibration value, and judging the abnormal vibration of the engine in a comparison manner. Compared with a current vibration limit threshold value monitoring method singly used in an external field, the method can find vibration abnormal characteristic expression earlier, provides a new discrimination method for external field vibration monitoring, can greatly improve external field vibration safety monitoring, and further guarantees the use safety of an engine.

Description

Technical Field

[0001] This application belongs to the field of fault diagnosis, and particularly relates to a method for monitoring the vibration characteristics and fault diagnosis of an aero-engine in the field. Background Art

[0002] For the aero-engines currently used in the field, the overall vibration value of the engine, as a monitoring means for the mechanical state or faults of the rotor system, is an important monitoring parameter. Together with other parameters, it can comprehensively judge whether the engine deviates from the good working state, helps to detect early faults, prevents the engine components from generating excessive loads and internal forces due to excessive vibration, and avoids secondary damage. Currently, for the engines used in the field, on the one hand, there are only a few or even only a single vibration measurement point for vibration, and the measurement of the total engine vibration cannot be analyzed in the frequency domain, which brings great difficulties to the early warning of vibration fault diagnosis. On the other hand, the current field monitoring of the overall vibration value of the engine is often a single-threshold judgment and limitation, that is, the engine does not exceed a certain limit value within a certain speed. Its monitoring method is relatively simple, and it is difficult to well identify some potential or developing faults during use, often missing the best time for diagnosis and causing relatively serious faults.

[0003] From the publicly published materials, there are few studies on the vibration safety monitoring of engines actually used in the field; currently, the research on the overall vibration fault prediction of aero-engines is mostly based on theoretical methods, generally based on a large number of measurement points and vibration information including detailed information such as frequency and phase, which is obviously inconsistent with the single measurement point and airborne DC signal of field engines.

[0004] The research on the vibration of field engines mainly focuses on its limit standards. Generally, the overall vibration limit value is obtained based on statistical methods. This method can still only obtain a single limit threshold in the field, and there are deficiencies in the vibration safety monitoring or fault diagnosis of field engines, often resulting in missed alarms in the field, unable to timely detect potential fault hazards, and affecting the safe use of engines.

[0005] To further improve the vibration safety monitoring in the field and ensure the safe use of engines, in combination with the current overall vibration monitoring scheme of field engines, a method for monitoring the vibration characteristics and fault diagnosis of engines based on the historical measured data of field engines is proposed. Summary of the Invention

[0006] The purpose of this application is to provide a method for monitoring the vibration characteristics and fault diagnosis of an aero-engine in the field to solve the problem that the existing fault diagnosis methods are prone to missed detections.

[0007] The technical solution of this application is: A method for monitoring the vibration characteristics and fault diagnosis of an aero-engine in the field, including:

[0008] From the engine flight history data, select the flight vibration data for a certain number of times, respectively obtain the high-pressure relative speed and the low-pressure relative speed in different flight vibration data, and record and save them;

[0009] Segment the high-pressure relative speed and the low-pressure relative speed according to the speed respectively, and then extract the vibration values under the same stable speed condition for each flight to calculate the average vibration value; obtain the curves of the average vibration values under the high-pressure relative speed and the low-pressure relative speed changing with the speed, that is, obtain the curves of the average vibration values of the engine changing with the speed respectively, which are the vibration characteristic curves of the high and low pressure rotors respectively;

[0010] Analyze the vibration characteristic curves of the high and low pressure rotors to find the speed corresponding to the maximum vibration value; take the average value of the vibration values within a certain interval of this speed according to the maximum vibration value, and draw the change trend line of the corresponding vibration value according to the calendar time of engine use, that is, obtain the change and development trend of the maximum vibration value;

[0011] Draw the vibration characteristic curves and the change and development trend lines of the maximum vibration values of multiple engines respectively, and make a comparison. If the vibration value of a certain engine is greater than the maximum vibration value of other engines and the interpolation of the development trend of this engine is continuously increasing, then diagnose that the engine has abnormal vibration.

[0012] Preferably, set a limit value for abnormal judgment. If the interpolation of this development trend does not exceed the limit value and has an increasing trend, it is necessary to compare with the trend of other engines in this working interval; if the interpolation of the development trend exceeds the limit value, directly determine its abnormality.

[0013] Preferably, obtain the development trend data, calculate the variance, peak value and kurtosis value of the development trend, and perform time-domain waveform analysis on the vibration signal. When the time-domain waveform exceeds the limit value, it is judged that the engine has abnormal vibration.

[0014] Preferably, the specific method for finding the maximum vibration value is: define the window length T w , search for the maximum value within the window; then compare the maximum value in the first window with the maximum value in the next window, find the larger vibration value and compare it with the next window; after comparing all the windows, the larger vibration value found is the maximum vibration value.

[0015] Preferably, after obtaining the historical vibration data, use the wavelet threshold denoising method to remove the noise.

[0016] Preferably, the certain number of times is 4 to 6 times, and the certain interval is ±2%.

[0017] The method for monitoring the vibration characteristics and diagnosing faults of an aero-engine in the field compares vibrations through the flight history data of the engine, obtains the high and low pressure relative speeds in the historical data, then calculates the average vibration value, and obtains the curves of the average vibration value varying with the speed at the high pressure relative speed and the low pressure relative speed; then analyzes the vibration characteristic curves of the high and low pressure rotors to find the speed corresponding to the maximum vibration value; finally, judges the abnormal vibration of the engine by analyzing the change and development trend of the maximum vibration value through comparison. Compared with the current method of monitoring only using the vibration limit threshold in the field, it can find the abnormal vibration characteristics earlier, provide a new discrimination method for the vibration monitoring in the field, greatly improve the vibration safety monitoring in the field, and further ensure the safe use of the engine. Brief Description of the Drawings

[0018] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0019] Figure 1 It is a schematic diagram of the overall process of this application. Detailed Embodiments

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] A method for monitoring the vibration characteristics and diagnosing faults of an aero-engine in the field, as Figure 1 described, includes the following steps:

[0022] Step S100, select the historical vibration data of the engine

[0023] Among the historical vibration data of the engine that has flown, select 4 to 6 flight vibration data (evenly distributed in time from the start of the engine's delivery and use to the flight day of analysis); respectively obtain the high pressure relative speed and the low pressure relative speed in different flight vibration data, and record and save them.

[0024] Preferably, after obtaining the historical vibration data, the wavelet threshold denoising method is used to remove the noise so as to obtain more accurate data.

[0025] Step S200, respectively draw the vibration characteristic curves of the high and low pressure rotors of the engine

[0026] Round up the high-pressure relative speed and low-pressure relative speed in the flight vibration data of different aircraft, then segment the high-pressure relative speed and low-pressure relative speed according to the speed respectively, and then extract the vibration values under the same stable speed condition of each flight to calculate the average vibration value; obtain the curves of the average vibration value varying with the speed under the high-pressure relative speed and low-pressure relative speed, that is, obtain the curves of the average vibration value of the engine varying with the speed respectively, which are the vibration characteristic curves of the high- and low-pressure rotors respectively.

[0027] In a specific example, extract the vibration amplitudes B1 to B6 at N H = 85% for 6 flight sorties respectively, and then calculate the average value B 平均 of B1 to B6, that is, obtain the vibration value under the high-pressure rotor speed N H = 85%. By analogy, the average vibration values B 平均， under each speed of the high-pressure and low-pressure can be obtained respectively. 平均 Plot the curve of B

[0028] varying with the speed.

[0029] Step S300: Analyze the vibration characteristic curves and select the maximum speed corresponding to the maximum vibration

[0030] Analyze the vibration characteristic curves of the high- and low-pressure rotors to find the speed corresponding to the maximum vibration. The speed corresponding to the maximum vibration is NH = 94%, that is, the maximum vibration in the high-pressure rotor vibration curve appears at the high-pressure 94% speed.

[0030] Preferably, the specific method for finding the maximum vibration is: Define the window length T w (such as 1 second), search for the maximum value within the window respectively; then compare the maximum value in the first window with the maximum value in the next window, find the larger vibration value and compare it with the next window; after comparing all windows, the larger vibration value found is the maximum vibration value.

[0031] Step S400: Plot the curve of the change and development trend of the maximum engine vibration

[0032] According to the speed corresponding to the maximum vibration, take the average value of the vibration values within the range of ±2% of this speed, and plot the change trend line of the corresponding vibration value according to the calendar time of the engine use, that is, obtain the change and development trend of the maximum vibration.

[0033] In a specific example, the maximum vibration in the high-pressure rotor vibration curve appears at the high-pressure 94% speed. Take the vibration values at the high-pressure speeds of 92% to 96% for each flight sortie respectively, and then calculate the average value, that is, obtain the maximum vibration value of this flight sortie; according to the calendar time of the engine use, plot the change trend line of the average vibration value within this speed range for each flight sortie, that is, obtain the change and development trend of the maximum vibration.

[0034] Step S500: Compare and analyze the vibration characteristics and maximum vibration values of multiple engines to conduct vibration fault diagnosis

[0035] Draw the change and development trend lines of the vibration characteristics and maximum vibration values of multiple engines respectively according to Steps S100 - S400, and make a comparison. If the vibration value of a certain engine is greater than that of other engines and its maximum vibration value, and the interpolation of the development trend of this engine is continuously increasing, although the absolute value of the vibration of this engine does not exceed the limit standard allowed in the field, it can still be diagnosed that the engine has abnormal vibration.

[0036] Preferably, set a limit value for abnormal judgment. If the interpolation of this development trend does not exceed the limit value and has an increasing trend, it is necessary to compare it with the trends of other engines in this working range; if the interpolation of the development trend exceeds the limit value, it is directly determined to be abnormal.

[0037] In a specific example, obtain the development trend data, calculate the variance, peak value, and kurtosis value of the development trend, and conduct time - domain waveform analysis on the vibration signal. When the time - domain waveform exceeds the limit value, it is judged that the engine has abnormal vibration.

[0038] In summary, the present application conducts vibration comparison through the flight history data of the engine, obtains the relative high - and low - pressure speeds in the historical data, then calculates the average vibration value, and obtains the curve of the average vibration value changing with the speed under the relative high - and low - pressure speeds; then analyzes the vibration characteristic curves of the high - and low - pressure rotors to find the speed corresponding to the maximum vibration value; finally, through analyzing the change and development trend of the maximum vibration value, the engine vibration abnormality is judged by comparison. Compared with the current single vibration limit threshold monitoring method used in the field, it can detect the abnormal vibration characteristic performance earlier, provides a new discrimination method for field vibration monitoring, can greatly improve the field vibration safety monitoring, and further ensure the safe use of the engine.

[0039] Finally, it should be noted that: in the attached drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved. For other structures, reference can be made to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0040] Finally: The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for monitoring the vibration characteristics and fault diagnosis of an aero-engine in the field, characterized in that, Including: In the engine flight history data, select the flight vibration data for a certain number of times, respectively obtain the high-pressure relative speed and the low-pressure relative speed in different flight vibration data, and record and save them; Segment the high-pressure relative speed and the low-pressure relative speed according to the speed respectively, and then extract the vibration values under the same stable speed condition of each flight sortie to calculate the average vibration value; obtain the curves of the average vibration values under the high-pressure relative speed and the low-pressure relative speed changing with the speed, that is, obtain the curves of the average vibration values of the engine changing with the speed respectively, which are the vibration characteristic curves of the high and low pressure rotors respectively; Analyze the vibration characteristic curves of the high and low pressure rotors to find the speed corresponding to the maximum vibration value; take the average value of the vibration values within a certain interval of this speed according to the maximum vibration value, and draw the corresponding change trend line of the vibration value according to the calendar time of engine use, that is, obtain the change and development trend of the maximum vibration value; Draw the vibration characteristic curves and the change and development trend lines of the maximum vibration values of multiple engines respectively, and make a comparison. If the vibration value of a certain engine is greater than the maximum vibration value of other engines and the interpolation of the development trend of this engine is continuously increasing, then diagnose that the engine has abnormal vibration.

2. The method for monitoring the vibration characteristics and fault diagnosis of an aero-engine on the field according to claim 1, characterized in that: Set a limit value for abnormal judgment. If the interpolation of this development trend does not exceed the limit value and there is an increasing trend, it is necessary to compare it with the trend of other engines in this working interval; if the interpolation of the development trend exceeds the limit value, directly judge it as abnormal.

3. The method for monitoring the vibration characteristics and fault diagnosis of an aero-engine in the field according to claim 1, wherein: Obtain the development trend data, calculate the variance, peak value and kurtosis value of the development trend, and perform time-domain waveform analysis on the vibration signal. When the time-domain waveform exceeds the limit value, judge that the engine has abnormal vibration.

4. The method for monitoring the vibration characteristics and fault diagnosis of an aero-engine in the field according to claim 1, wherein: The specific method for finding the maximum vibration value is as follows: Define the window length T w , and search for the maximum value within the window; then compare the maximum value in the first window with the maximum value in the next window, find the larger vibration value and compare it with the next window; after comparing all windows, the larger vibration value found is the maximum vibration value.

5. The method for monitoring the vibration characteristics and fault diagnosis of an aero-engine in the field according to claim 1, characterized in that: After obtaining the historical vibration data, adopt the method of wavelet threshold denoising to remove the noise.

6. The method for monitoring the vibration characteristics and fault diagnosis of an aero-engine on the field according to claim 1, wherein: The certain number of times is 4 to 6 times, and the certain interval is ±2%.

Images