Aero-engine surge margin screening method based on compressor parameters

Abstract

The invention provides an aero-engine surge margin screening method based on gas compressor parameters. The aero-engine surge margin screening method comprises the following steps that firstly, pressure value parameter collection is conducted in the engine test run rotating speed rising process through two outlet total pressure measuring sensors; 2, processing based on the collected pressure value parameter to obtain a secondary processing pressure value parameter; and 3, calculating by utilizing the secondary processing pressure value parameter, and returning a characteristic curve. According to the method, the surge margin of the engine is quickly and efficiently judged by performing data feature processing on the pressure monitoring parameters of the conventional compressor of the aero-engine, and a new method and thought are provided for screening the surge margin of the aero-engine; the method is applied to the surge screening work of the aero-engine; theoretical analysis and test verification show that after the method is applied, the surge screening result optimization effect is obvious, the surge screening requirement is fully met, and the test cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft engine testing, and in particular to an aircraft engine surge margin screening method based on compressor parameters. Background Art

[0002] The surge margin of aircraft engines is an important indicator to measure the ability of aircraft engines to work stably under non-design conditions. Surge is an unstable working state of aircraft engines, which is manifested by strong pulsation of airflow and sharp deterioration of engine performance. The surge margin reflects the distance between the normal working state of the engine and the surge boundary. Therefore, the screening of aircraft engine surge margin is of great significance to ensure the stability and safety of the engine.

[0003] For the screening of aircraft engine surge margin, according to the existing test methods, the surge margin is tested by simulating the conditions of intake distortion or fuel surge. It is mainly through changing the engine inlet airflow field or increasing the fuel flow under the engine working state to simulate the engine main engine oil-gas mismatch condition. This method can achieve the purpose of finding the engine surge margin, but it needs to increase additional test time and test costs, resulting in a great waste of test resources. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention proposes a method for screening surge margin of aircraft engines based on compressor parameters, which solves the problem of extra consumption caused by cumbersome supplementary tests in the surge margin screening process of aircraft engines; by performing data feature processing on conventional compressor pressure monitoring parameters of aircraft engines, the surge margin of the engine is quickly and efficiently determined, providing a new method and idea for surge margin screening of aircraft engines.

[0005] In view of this, a method for screening surge margin of an aircraft engine based on compressor parameters of the present invention comprises the following steps:

[0006] Step 1: Collect pressure value parameters during the engine test speed increase process using two outlet total pressure measurement sensors;

[0007] Step 2: Processing the collected pressure value parameters to obtain secondary processed pressure value parameters;

[0008] Step three: Calculate using the secondary processing pressure value parameters and return a pressure characteristic curve; when a pressure characteristic sudden drop level greater than 100 units appears in the pressure characteristic curve, it is determined that the surge margin of the engine is insufficient.

[0009] Preferably, the two types of outlet total pressure measurement sensors in step one are respectively a transient analog signal total pressure measurement sensor and a discrete digital signal total pressure measurement sensor; the data collected by the transient analog signal total pressure measurement sensor is an analog signal pressure value parameter, and the data collected by the discrete digital signal total pressure measurement sensor is a digital signal pressure value parameter.

[0010] Preferably, in the step 2, high-pass filtering is performed on the collected digital signal pressure value parameters to obtain secondary processed digital signal pressure value parameters.

[0011] Preferably, the high-pass filtering process is to process the digital signal pressure value parameter according to formula (1) to obtain a secondary processed digital signal pressure value parameter, wherein formula (1) is:

[0012]

[0013] In the formula, is the secondary processing digital signal pressure value parameter of the nth point, is the digital signal pressure value parameter of the nth point, for The digital signal pressure parameter value corresponding to the interval time T' before the point, for The digital signal pressure parameter value corresponding to the interval time before the point is 2T', for The digital signal pressure parameter value corresponding to the interval time before the point is 3T', for The interval time before the point is 4T' corresponding to the digital signal pressure parameter value, where T' is the unit time interval.

[0014] Preferably, in step three, the characteristic data is obtained by secondary processing of the difference between the digital signal pressure value parameter and the analog signal pressure value parameter.

[0015] Preferably, the difference calculation process is to perform difference processing on the analog signal pressure value parameter and the secondary processed digital signal pressure value parameter according to formula (2). For any time, formula (2) is:

[0016]

[0017] In the formula, is the feature data of the nth point, is the pressure value parameter of the analog signal at the nth point, It is the pressure value parameter of the secondary processed data signal at the nth point.

[0018] Preferably, in the step three, a pressure characteristic curve is drawn according to the characteristic data and the number of revolutions of the engine.

[0019] The beneficial effects of the present invention are:

[0020] 1. During the routine delivery test of aircraft engines, the present invention processes conventional compressor pressure monitoring parameters, amplifies slight differences in aircraft engine pressure monitoring parameters, and makes them become pressure change characteristic lines per unit data acquisition cycle. By drawing a relationship curve between the pressure change characteristic line and a specific speed in the engine transition state, the pressure anomaly of an engine with a low margin is discovered. By accumulating periodic data, an empirical boundary curve is drawn. By judging the processed data, the engine surge margin can be quickly and efficiently surveyed.

[0021] 2. The present invention has been applied to the surge screening of aircraft engines; data processing is performed on conventional compressor pressure monitoring parameters to achieve feature amplification and quickly and effectively determine the surge margin of the engine main engine. Through theoretical analysis and experimental verification, the optimization effect of the surge screening results after applying this method is obvious, which fully meets the needs of surge screening and reduces the test cost.

[0022] 3. The surge screening method of the present invention can realize surge margin screening more quickly and determine the surge margin of the engine main engine, providing a new, fast and efficient method for the cumbersome and complex problem of surge margin screening of aircraft engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The characteristic curve of the relationship between the compressor pressure difference and the speed of the engine with abnormal surge margin of the present invention;

[0024] Figure 2 The characteristic curve of the relationship between the compressor pressure value and the rotation speed of the engine with normal surge margin of the present invention;

[0025] Figure 3 The curve showing the relationship between the compressor pressure simulation signal and the rotation speed of the engine with abnormal surge margin of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] The basic principles of the compressor parameter-based aero-engine surge margin screening method of the present invention are as follows:

[0028] During routine delivery tests of aircraft engines, the conventional compressor pressure monitoring parameters are processed to become the pressure change characteristic line per unit data acquisition cycle. By plotting the relationship curve between the pressure change characteristic line and the specific speed of the engine transition state, the pressure anomaly of the engine with a low margin is discovered. By accumulating data over a certain period of time, an empirical boundary curve is drawn to quickly determine the surge margin of the engine main engine.

[0029] Example 1

[0030] The present invention provides a method for screening surge margin of an aircraft engine based on compressor parameters, comprising the following steps:

[0031] Step 1: Collect pressure value parameters during the engine test speed increase process using two outlet total pressure measurement sensors;

[0032] Step 2: Processing the collected pressure value parameters to obtain secondary processing pressure value parameters;

[0033] Step 3: Calculate using the secondary processing pressure value parameters and return the pressure characteristic curve; when a pressure characteristic sudden drop level greater than 100 units appears in the pressure characteristic curve, it is determined that the engine surge margin is insufficient.

[0034] In step 1, two outlet total pressure measurement sensors are installed at the outlet of the engine compressor. The two outlet total pressure measurement sensors are a transient analog signal total pressure measurement sensor and a discrete digital signal total pressure measurement sensor. The two sensors are used to record the pressure value parameter P of the engine during the speed increase process. DIG and P SIM , where P SIM P is the analog signal pressure value parameter collected by the transient analog signal total pressure measurement sensor, DIG It is the digital signal pressure value parameter collected by the discrete digital signal total pressure measurement sensor.

[0035] In step 2, according to the pressure value parameter P of the collected digital signal DIG Perform high-pass filtering to obtain the secondary processing digital signal pressure value parameter P SL .

[0036] In step 3, the pressure value parameter P of the digital signal is processed twice. SL The analog signal pressure value parameter P SIM The characteristic data P is calculated by the difference between T , and according to the characteristic data P T The pressure characteristic curve is plotted against the engine speed N'.

[0037] In this embodiment, the above difference calculation method needs to be based on the following principle: When the sensor measures the inside of the engine compressor, it usually collects the airflow pressure around a point on the airflow cross section. Since the airflow in the real state is uneven, judging the airflow state on the entire cross section by one point is one-sided and it is easy to miss the key pressure characteristic changes. Therefore, when applying this method, it is necessary to consider the airflow difference on the cross section under specific conditions or increase the number of sensors to improve the sampling authenticity;

[0038] Further, in step 3, according to the pressure value parameter of the digital signal at the nth point And the secondary processing digital signal pressure value parameter of the nth point Calculate the characteristic data of the nth point And take the nth point feature data is the vertical coordinate, the speed of the nth point is N' n Plot the pressure characteristic curve on the abscissa.

[0039] Example 2

[0040] A method for screening an aircraft engine surge margin based on compressor parameters in this embodiment includes the following steps:

[0041] Step 1: Install two outlet total pressure measurement sensors at the outlet of the engine compressor, namely, a transient analog signal total pressure measurement sensor and a discrete digital signal total pressure measurement sensor. Use the two outlet total pressure measurement sensors to record the pressure value parameters of the engine during the speed increase process, and obtain two sets of pressure value parameters with a time interval of T', which are the analog signal pressure value parameters P SIM And the digital signal pressure value parameter P DIG , and each data point obtains the corresponding actual engine speed N', and the data examples are shown in Table 1 below.

[0042] Table 1 Data set after collection

[0043]

[0044] Step 2: For any point n, convert the digital signal pressure value parameter P of the nth point DIG The pressure value parameter of the secondary processed digital signal of the nth point is obtained by processing according to the following formula (1): Formula (1) is as follows:

[0045]

[0046] In the formula, is the digital signal pressure value parameter of the nth point; for The digital signal pressure parameter value corresponding to the interval time T' before the point; for The digital signal pressure parameter value corresponding to the interval time before the point is 2T'; for The digital signal pressure parameter value corresponding to the interval time before the point is 3T'; for The interval time before the point is 4T' corresponding to the digital signal pressure parameter value; T' is the unit time interval.

[0047] Substituting the data in Table 1 into formula (1), a new set of data is obtained, as shown in Table 2 below:

[0048] Table 2 Data set after secondary processing

[0049]

[0050] Step 3: For any point n, set the analog signal pressure value parameter P SIM And the secondary processing digital signal pressure value parameter P SL Perform difference processing. For any time nT', the difference processing formula (2) is as follows:

[0051]

[0052] In the formula, is the characteristic data of the nth point; The pressure value parameter of the analog signal at the nth point; It is the pressure value parameter of the secondary processed data signal at the nth point.

[0053] Substituting the data in Table 2 into formula (2), a new set of data is obtained, as shown in Table 3 below:

[0054] Table 3 Final data

[0055]

[0056] The characteristic data of the nth point after the difference processing of the corresponding time series is the ordinate, speed N' n A pressure characteristic curve is drawn as the horizontal axis; when a pressure characteristic sudden drop level greater than 100 units appears in the pressure characteristic curve, it is judged that the engine surge margin is insufficient, as described below:

[0057] See also Figure 1 and Figure 2 As shown, Figure 1 The characteristic curve of the relationship between the compressor pressure difference and the speed of the engine with abnormal surge margin; Figure 2 This is the characteristic curve of the relationship between compressor pressure and speed of an engine with normal surge margin; Figure 1 and Figure 2 It can be seen that Figure 2 The marked part in the middle is the characteristic performance of low surge margin.

[0058] See also Figure 3 As shown, Figure 3 This is the relationship curve between the compressor pressure simulation signal and the speed of the engine with abnormal surge margin. Figure 1 and Figure 3 The curves obtained from the tests conducted on the same engine are compared Figure 1 and Figure 3 It can be seen that Figure 3 It is not possible to directly find abnormal pressure value parameters, but after processing and calculation, Figure 1 The curve clearly shows the abnormality of the pressure value parameter.

[0059] The working principle of the compressor parameter-based aero-engine surge margin screening method of the present invention is as follows:

[0060] The increase in engine speed is achieved by increasing the fuel supply. In this process, surge is more likely to occur due to a certain degree of mismatch between the inlet air flow and the fuel. Surge is manifested in the engine compressor as air loss or pressure pulsation. Mild air loss or pressure pulsation will not cause surge, but a certain degree of air loss or pressure pulsation is not easy to detect and will cause the surge margin to decrease.

[0061] As the engine fuel supply increases and the speed rises (usually Figure 1 During the process of the horizontal coordinate 75 to 92 in the middle), the pressure at the compressor outlet will increase monotonically. The original rising process is filtered by high-pass signal through secondary processing of the digital signal to reduce the signal rising slope, and then the difference processing with the analog signal part is performed to obtain the characteristic performance. Since the fuel supply increases monotonically in the speed range of 75 to 92, the growth rate of the analog signal part will be significantly higher than that of the high-pass signal filtering part. If there is a sharp drop, it proves that there is gas loss or pressure pulsation inside the compressor, resulting in abnormal increase in the compressor outlet pressure (see Figure 1 Marked part), a slight drop or fluctuation is within an acceptable range. The present invention uses this method to quickly find abnormalities inside the engine by numerically characterizing the incremental abnormalities that are difficult to find, replacing conventional additional test methods. Through the surge margin screening of this method, the surge margin of the engine main engine can be quickly determined, and special adjustments or remedial work can be performed on engines with low surge margins to eliminate the impact of the problem and control engines with quality risks before the delivery cycle.

Claims

1. A method for screening surge margin of an aircraft engine based on compressor parameters, characterized in that: The steps include: Step 1: Collect pressure value parameters during the engine test speed increase process using two outlet total pressure measurement sensors; Step 2: Processing the collected pressure value parameters to obtain secondary processed pressure value parameters; Step three: Calculate using the secondary processing pressure value parameters and return a pressure characteristic curve; when a pressure characteristic sudden drop level greater than 100 units appears in the pressure characteristic curve, it is determined that the surge margin of the engine is insufficient.

2. The method for screening surge margin of an aircraft engine based on compressor parameters according to claim 1, characterized in that: The two types of outlet total pressure measurement sensors in step one are respectively a transient analog signal total pressure measurement sensor and a discrete digital signal total pressure measurement sensor; the data collected by the transient analog signal total pressure measurement sensor is an analog signal pressure value parameter, and the data collected by the discrete digital signal total pressure sensor is a digital signal pressure value parameter.

3. The method for screening surge margin of an aircraft engine based on compressor parameters according to claim 2, characterized in that: In the step 2, high-pass filtering is performed on the collected digital signal pressure value parameters to obtain secondary processed digital signal pressure value parameters.

4. The method for screening aircraft engine surge margin based on compressor parameters according to claim 3, characterized in that: The high-pass filtering process is to process the digital signal pressure value parameter according to formula (1) to obtain the secondary processing digital signal pressure value parameter, wherein formula (1) is: In the formula, is the secondary processing digital signal pressure value parameter of the nth point, is the digital signal pressure value parameter of the nth point, for The digital signal pressure parameter value corresponding to the interval time T' before the point, for The digital signal pressure parameter value corresponding to the interval time before the point is 2T', for The digital signal pressure parameter value corresponding to the interval time before the point is 3T', for The interval time before the point is 4T' corresponding to the digital signal pressure parameter value, where T' is the unit time interval.

5. The method for screening aircraft engine surge margin based on compressor parameters according to claim 3, characterized in that: In the step three, characteristic data is obtained by secondary processing the difference between the digital signal pressure value parameter and the analog signal pressure value parameter.

6. The method for screening aircraft engine surge margin based on compressor parameters according to claim 5, characterized in that: The difference calculation process is to perform difference processing on the analog signal pressure value parameter and the secondary processing digital signal pressure value parameter according to formula (2). For any time, formula (2) is: In the formula, is the feature data of the nth point, is the pressure value parameter of the analog signal at the nth point, It is the pressure value parameter of the secondary processed data signal at the nth point.

7. The method for screening aircraft engine surge margin based on compressor parameters according to claim 5, characterized in that: In the step three, a pressure characteristic curve is drawn according to the characteristic data and the engine speed.

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