Electrostatic charge calibration system and electrostatic particle charging quantity calculation method

Abstract

The present application relates to the technical field of aero-engine state monitoring, in particular to an electrostatic quantity calibration system and an electrostatic particle charging quantity calculation method; the electrostatic quantity calibration system is set to include an electrostatic generator, an electrostatic transmission cable, an electrostatic generator gun, a positioning hopper, an electrostatic sensor and a signal conditioning and acquisition device; the position coordinates of the particles to be tested in the cross section of the engine tail jet path are calculated according to the three-point positioning method; the voltage value measured by the electrostatic quantity correction system and the correction coefficient of the electrostatic quantity correction system are combined to determine the size of the charge quantity of the particles to be tested; and the health state of the engine gas path components is judged according to the size of the charge quantity; the size of the particles to be tested is reflected by calculating the charge quantity, and the reliability of the engine early warning is improved.

Description

Technical Field

[0001] This invention relates to the field of aircraft engine condition monitoring, and more specifically, to an electrostatic calibration system and a method for calculating the charge of electrostatic particles. Background Technology

[0002] Due to their numerous intricate structures and the fact that they operate under harsh conditions such as high temperature, high pressure, variable load, and high stress, aero-engine airflow components are highly susceptible to performance degradation and failures such as blade burning and fatigue damage. These failures can even lead to the malfunction of the entire system, causing significant losses. Airflow components are widely recognized as a major source of aero-engine failure. Therefore, the reliability of airflow components not only affects engine efficiency and operating costs but also equipment safety and personnel safety. Statistics show that in my country's flight accidents over the past decade, engine-related failures accounted for more than 60% of mechanical and maintenance failures, with airflow component failures accounting for approximately 90% of these. These failures not only incur high repair costs but also often result in extremely serious accidents. Therefore, online monitoring of the condition of engine airflow components is essential. Summary of the Invention

[0003] This invention addresses the issue of insufficient reliability in online monitoring and early warning of engine airflow components by proposing an electrostatic calibration system and a method for calculating the charge of electrostatic particles. The electrostatic calibration system comprises an electrostatic generator, an electrostatic transmission cable, an electrostatic generator gun, a positioning funnel, an electrostatic sensor, and a signal conditioning and acquisition device. It calculates the position coordinates of the test particle on the cross-section of the engine's exhaust jet path using a three-point positioning method. Combining the voltage value measured by the electrostatic calibration system with its correction coefficients, the magnitude of the test particle's charge is determined. The health status of the engine airflow components is then judged based on the charge magnitude. By calculating the charge, the size of the test particle is reflected, thus improving the reliability of engine early warning systems.

[0004] The specific implementation details of this invention are as follows: An electrostatic calibration system for calibrating test particles in an engine exhaust nozzle includes an electrostatic generator, an electrostatic transmission cable, an electrostatic generator gun, a positioning funnel, an electrostatic sensor, and a signal conditioning and acquisition device. One end of the electrostatic generator gun is connected to the electrostatic generator via an electrostatic transmission cable, and the other end is connected to the positioning funnel. The central axis of the positioning funnel is coaxial with the central axis of the engine exhaust nozzle; the test particle is located above the central axis of the positioning funnel. The electrostatic sensor is mounted on the engine exhaust nozzle and connected to the signal conditioning and acquisition device via a cable.

[0005] To better realize the present invention, the electrostatic sensor is further configured as three; the axial spacing between adjacent electrostatic sensors among the three electrostatic sensors is m, and they are distributed at an angle of 120° in the axial section projection.

[0006] Based on the electrostatic calibration system proposed above, in order to better realize the present invention, a method for calculating the charge of electrostatic particles is further proposed. The method calculates the position coordinates of the test particle on the cross-section of the exhaust jet path of the engine according to the three-point positioning method, and combines the voltage value measured by the electrostatic calibration system and the correction coefficient of the electrostatic calibration system to determine the magnitude of the charge of the test particle, and judges the health status of the engine gas path components based on the magnitude of the charge.

[0007] To better realize the present invention, the method for calculating the charge of electrostatic particles further includes the following steps: Step 1: Obtain the peak voltage V of the test particle from three electrostatic sensors installed on the engine exhaust nozzle. i And according to the peak voltage V i Obtain the charge correction curve; Step 2: Select one of the electrostatic sensors as the origin to establish a rectangular coordinate system, obtain the distances of the test particle to the three electrostatic sensors respectively, and obtain the voltage ratio of the three electrostatic sensors based on the distances; Step 3: Determine the magnitude of the voltage ratio. If the voltage ratio is equal to 1, the particle under test is located on the perpendicular bisector of the two electrostatic sensors, and the charge of the particle under test is obtained according to the charge correction curve; otherwise, it is located at the center of the circle, and the center coordinates of the circle are calculated; the center of the circle is located on the circle connecting the two electrostatic sensors. Step 4: Based on the center coordinates, establish a set of trajectory equations for the test particle to obtain its position coordinates; Step 5: Based on the location coordinates, combined with the voltage value measured by the electrostatic calibration system and the correction coefficient of the electrostatic calibration system, calculate the charge of the test particle, and determine the health status of the engine air circuit components based on the magnitude of the charge.

[0008] To better implement this invention, step 2, calculating the voltage ratio, is further performed as follows:

[0009] Wherein, d1, d2, and d3 are the distances from the three electrostatic sensors to the particle under test, k1, k2, and k3 are the voltage ratios of the three electrostatic sensors, and v1, v2, and v3 are the peak voltages of the three electrostatic sensors.

[0010] To better realize the present invention, the center coordinates in step 3 are further defined as: O1 O2 O3 ; Where k1, k2, and k3 are the voltage ratios of the three electrostatic sensors, L is the distance between two of the electrostatic sensors, and D is the radius of the engine exhaust nozzle.

[0011] To better realize the present invention, the trajectory equation set established in step 4 is further as follows:

[0012] Where x is the abscissa of the test particle, y is the ordinate of the test particle, k1, k2, and k3 are the voltage ratios of the three electrostatic sensors, L is the distance between two of the electrostatic sensors, and D is the radius of the engine exhaust nozzle.

[0013] To better realize the present invention, further, the specific operation of calculating the charge of the test particle in step 5 is as follows:

[0014] Where g is the correction coefficient of the electrostatic calibration system described above, and v i The voltage value obtained by the electrostatic calibration system, d i The distance between the calculated position coordinates Q(x, y) of the test particle and any one of the three electrostatic sensors.

[0015] The present invention has the following beneficial effects: This invention establishes an electrostatic calibration system and, by combining the voltage value measured by the electrostatic calibration system with the correction coefficient of the electrostatic calibration system, determines the magnitude of the charge of the test particle. The magnitude of the charge reflects the size of the test particle, and the health status of the engine's air passage components is judged based on the magnitude of the charge, thereby improving the reliability of engine early warning. Attached Figure Description

[0016] Figure 1 This is a layout diagram of an electrostatic sensor provided in an embodiment of the present invention.

[0017] Figure 2 This is a diagram of the electrostatic calibration system provided in an embodiment of the present invention.

[0018] Figure 3 This is a positioning calculation diagram provided in an embodiment of the present invention.

[0019] Among them, 1. electrostatic generator, 2. electrostatic transmission cable, 3. electrostatic generator gun, 4. positioning funnel, 5. test particle, 6. engine tail nozzle, 7. electrostatic sensor, 8. cable, 9. signal conditioning and acquisition device, 10. electrostatic sensor A, 11. electrostatic sensor B, 12. electrostatic sensor C. Detailed Implementation

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments, and therefore should not be regarded as a limitation on the scope of protection. 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.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1: This embodiment proposes an electrostatic calibration system for calibrating test particles 5 in an engine tailpipe 6, including an electrostatic generator 1, an electrostatic transmission cable 2, an electrostatic generating gun 3, a positioning funnel 4, an electrostatic sensor 7, and a signal conditioning and acquisition device 9. One end of the electrostatic generator 3 is connected to the electrostatic generator 1 via the electrostatic transmission cable 2, and the other end is connected to the positioning funnel 4; The central axis of the positioning funnel 4 is coaxial with the central axis of the engine tail nozzle 6; the test particle 5 is located above the central axis of the positioning funnel 4. The electrostatic sensor 7 is mounted on the engine exhaust nozzle 6 and is connected to the signal conditioning and acquisition device 9 via a cable 8.

[0023] To better realize the present invention, the electrostatic sensor 7 is further configured as three; the distance between adjacent electrostatic sensors 7 in the axial direction is m, and they are distributed at an angle of 120° in the axial section projection.

[0024] Working principle: such as Figure 2As shown, the electrostatic calibration system is activated, and the test particle 5 is fed into the positioning funnel 4. At this time, the electrostatic generator 1 releases a fixed amount of static charge, which is then transferred to the test particle 5 via the electrostatic transmission cable 2 and the electrostatic generator 3. The test particle 5, carrying a fixed amount of charge, falls downward through the center of the engine exhaust nozzle 6. After the three electrostatic sensors 7 detect the static electricity, the signals are sent to the signal conditioning and acquisition device 9 via the cable 8 for signal amplification. The peak voltage of the amplified signal is V. min ~V max Between. By adjusting electrostatic generator 1, V can be sampled and obtained. min ~V max The voltage values ​​corresponding to the N charges are used to form a charge correction curve, which is stored in the signal conditioning and acquisition device 9.

[0025] Example 2: Based on Embodiment 1 above, this embodiment uses a three-point positioning method combined with small signal sampling technology to calculate the coordinate position of charged particles in the cross-section of the engine exhaust jet path, and further determines the magnitude of the charge of the charged particles, which is then used to determine the health status of engine gas path components.

[0026] Specifically, the following steps are included: Step 1: Obtain the peak voltage V of the test particle 5 from three electrostatic sensors 7 installed on the engine exhaust nozzle. i And according to the peak voltage V i The charge correction curve is obtained.

[0027] Step 2: Select one of the electrostatic sensors 7 as the origin to establish a rectangular coordinate system, and obtain the distances of the test particle 5 to the three electrostatic sensors 7 respectively. Based on the distances, obtain the voltage ratio of the three electrostatic sensors 7.

[0028] Step 3: Determine the magnitude of the voltage ratio. If the voltage ratio is equal to 1, the test particle 5 is located on the perpendicular bisector of the two electrostatic sensors 7, and the charge of the test particle 5 is obtained according to the charge correction curve; otherwise, it is located at the center of the circle, and the center coordinates of the circle are calculated; the center of the circle is located on the circle connecting the two electrostatic sensors 7.

[0029] Step 4: Based on the center coordinates, establish a set of trajectory equations for the test particle 5 to obtain the position coordinates of the test particle 5.

[0030] Step 5: Based on the position coordinates, combined with the voltage value measured by the electrostatic calibration system and the correction coefficient of the electrostatic calibration system, calculate the charge of the test particle 5, and determine the health status of the engine air circuit components based on the magnitude of the charge.

[0031] The layout of the electrostatic sensor 7 on the engine exhaust nozzle 6 is as follows: Figure 1 As shown, the three electrostatic sensors 7 are equidistantly distributed along the axial direction of the engine exhaust nozzle 6 at intervals of m; their projections along the axial section are distributed at equal angles of 120°. When charged particles pass through the engine exhaust nozzle 6 at high speed, the distance difference between the three electrostatic sensors 7 on the engine exhaust nozzle 6 will generate three peak signals on the time axis. These three electrostatic sensors 7 are connected to the same signal conditioning and acquisition device 9 through cables of the same material, length, and structure for amplification. In this way, the peak values ​​of the three signals can be identified as V1, V2, and V3, respectively.

[0032] The measurement of the charge carried by charged particles begins by measuring the peak voltage V of the particle whose charge is to be fixed using a charge calibration system. i， This voltage value is calibrated to the corresponding charge value. Within the designed measurement range, as many calibrations as possible are performed to form a complete calibration curve. During actual measurement, the first peak is generated by electrostatic sensor A10, the second peak by electrostatic sensor B11, and the third peak by electrostatic sensor C12. The corresponding charge Q can be obtained by comparing each peak with the calibration curve. i See the electrostatic calibration system. Figure 2 .

[0033] The determination of the coordinate position of charged particles is determined by... Figure 3 As shown, a rectangular coordinate system is established with point A as the origin. When the measured values ​​V1=V2=V3, the charged particle Q is located at the center O' of the engine exhaust nozzle; otherwise, Q is located at other positions on the exhaust nozzle O'. Assuming the distances from the three electrostatic sensors A10, B11, and C12 to the charged particle Q are d1, d2, and d3 respectively, then: (1) Based on the characteristics of equal-distance curves: when k i When = 1, the trajectory of point Q lies on the perpendicular bisector of the line connecting the two points; otherwise, it lies on a circle whose center is on the line connecting the two points, and the center and radius of the corresponding circle are as follows: (2) Where, k i The ratio of the voltages measured by electrostatic sensors A10, B11, and C12; L is the distance between AB, AC, or BC; and D is the radius of the engine exhaust nozzle.

[0034] Establish the system of equations for the trajectory of point Q: (3) The coordinates of point Q (x, y) can be obtained by solving the system of equations (3).

[0035] Determination of charge Q: Based on the inverse relationship between the charge of a charged particle and the square of the distance, we can obtain: (4) Where g is the correction coefficient, derived from... Figure 2 The electrostatic calibration system shown provides; v i d is the measured value. i To calculate the distance between the Q(x, y) coordinates and one of the points A, B, or C, we can use the distance formula between two points in the given coordinate system:

[0036] Find d i In this way, the charge of the charged particle can be obtained according to equation (4).

[0037] Working principle: In the actual measurement process, such as Figure 2 As shown, similarly, press on the engine exhaust nozzle 6. Figure 1 Three electrostatic sensors 7 are required, connected to a signal conditioning and acquisition device 9 via cables 8. When strong electrostatically charged particles appear in the engine exhaust, the signal conditioning and acquisition device 9 will sample three peak voltages V1, V2, and V3 through the three electrostatic sensors 7. When V1=V2=V3, the electrostatically charged particles are located at the center of the transverse cross-section of the engine exhaust nozzle 6, i.e., at the center of the circle of the engine exhaust nozzle 6. The magnitude of their charge can be obtained by comparing the measured V values ​​with the charge correction curve. When one of the V values ​​differs from the others, the following applies: Figure 3 The positioning calculation diagram is used for calculation. First, calculate d1, d2, and d3 according to formula (1); then determine the center and radius of the three equally spaced circles according to formula (2); then form a system of equally spaced circle equations according to formula (3), and solve for the coordinates Q(x, y) of the charged particle Q point. Finally, calculate the charge of the charged particle according to formula (4).

[0038] The other parts of this embodiment are the same as those in Embodiment 1 above, so they will not be described again.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for calculating the charge of electrostatic particles, characterized in that, First, the position coordinates of the test particle (5) on the cross section of the engine exhaust path are calculated according to the three-point positioning method. Then, the magnitude of the charge of the test particle (5) is determined by combining the voltage value measured by the electrostatic calibration system and the correction coefficient of the electrostatic calibration system. Finally, the health status of the engine air passage components is judged according to the magnitude of the charge. The electrostatic calibration system is used to calibrate the test particles (5) in the engine tail nozzle (6), and includes an electrostatic generator (1), an electrostatic transmission cable (2), an electrostatic generator gun (3), a positioning funnel (4), an electrostatic sensor (7), and a signal conditioning and acquisition device (9). One end of the electrostatic generator (3) is connected to the electrostatic generator (1) via an electrostatic transmission cable (2), and the other end is connected to the positioning funnel (4); The central axis of the positioning funnel (4) coincides with the central axis of the engine tail nozzle (6); The electrostatic sensor (7) is mounted on the engine tail nozzle (6) and connected to the signal conditioning and acquisition device (9) via a cable (8); Specifically, the following steps are included: Step 1: Obtain the peak voltage V of the test particle (5) from three electrostatic sensors (7) installed on the engine exhaust nozzle (6). i And according to the peak voltage V i Obtain the charge correction curve; Step 2: Select one of the electrostatic sensors (7) as the origin to establish a rectangular coordinate system, obtain the distances of the test particle (5) to the three electrostatic sensors (7) respectively, and obtain the voltage ratio of the three electrostatic sensors (7) based on the distances; Step 3: Determine the magnitude of the voltage ratio. If the voltage ratio is equal to 1, the test particle (5) is located on the perpendicular bisector of the two electrostatic sensors (7). The charge of the test particle (5) is obtained according to the charge correction curve. Otherwise, it is located at the center of the circle. Calculate the center coordinates of the circle. The center of the circle is located on the circle connecting the two electrostatic sensors (7). Step 4: Based on the center coordinates, establish a set of trajectory equations for the test particle (5) to obtain the position coordinates of the test particle (5); Step 5: Based on the position coordinates, combined with the voltage value measured by the electrostatic calibration system and the correction coefficient of the electrostatic calibration system, calculate the charge of the test particle (5), and determine the health status of the engine air circuit components based on the magnitude of the charge. Step 2, calculating the voltage ratio, involves the following steps: ； Wherein, d1, d2, and d3 are the distances from electrostatic sensor A (10), electrostatic sensor B (11), and electrostatic sensor C (12) to the test particle (5), respectively; k1 is the voltage ratio measured by electrostatic sensor A (10) and electrostatic sensor B (11); k2 is the voltage ratio measured by electrostatic sensor A (10) and electrostatic sensor C (12); k3 is the voltage ratio measured by electrostatic sensor B (11) and electrostatic sensor C (12); and v1, v2, and v3 are the voltage peak values ​​of electrostatic sensor A (10), electrostatic sensor B (11), and electrostatic sensor C (12), respectively. The coordinates of the center of the circle in step 3 are: O1 O2 O3 ; ； Where L is the distance between electrostatic sensor A (10) and electrostatic sensor B (11), or between electrostatic sensor A (10) and electrostatic sensor C (12), or between electrostatic sensor B (11) and electrostatic sensor C (12); D is the radius of the engine tail nozzle (6).

2. The method for calculating the charge of electrostatic particles according to claim 1, characterized in that, The trajectory equations established in step 4 are as follows: ； Where x is the abscissa of the test particle (5), y is the ordinate of the test particle (5), k1 is the voltage ratio measured by electrostatic sensor A (10) and electrostatic sensor B (11), k2 is the voltage ratio measured by electrostatic sensor A (10) and electrostatic sensor C (12), k3 is the voltage ratio measured by electrostatic sensor B (11) and electrostatic sensor C (12), L is the distance between electrostatic sensor A (10) and electrostatic sensor B (11) or between electrostatic sensor A (10) and electrostatic sensor C (12) or between electrostatic sensor B (11) and electrostatic sensor C (12); D is the radius of the engine tail nozzle (6).

3. The method for calculating the charge of electrostatic particles according to claim 2, characterized in that, The specific operation for calculating the charge of the test particle (5) in step 5 is as follows: ； Where g is the correction coefficient of the electrostatic calibration system, v i The voltage value obtained by the electrostatic calibration system, d i The distance between the calculated position coordinates Q(x, y) of the test particle (5) and the electrostatic sensor.

4. The method for calculating the charge of electrostatic particles according to claim 1, characterized in that, The axial distance between two adjacent electrostatic sensors (7) is m, and the angle between the projections of two adjacent electrostatic sensors (7) on the axial section is 120°.

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