Non-invasive aero-engine state monitoring system and implementation method

Abstract

The application provides a non-invasive aero-engine state monitoring system and an implementation method.The whole system comprises an electric field sensor, an exhaust gas electric field sensing device, a signal acquisition device and a computer.The electric field sensor is carried on the exhaust gas electric field sensing device to obtain the electric quantity of the exhaust gas, and the measured data is sent to the computer through the signal acquisition device, and the signal processing, analysis and display are completed in the computer.The aero-engine state sensing adopts the mode of measuring the electric field value around the electrically charged particles in the exhaust gas, the analysis mode adopts a total charge amount estimation method in a closed space based on Gauss theorem, the charge amount of the electrically charged particles in the exhaust gas is estimated based on the measured electric field, the corresponding relationship between the exhaust gas charge amount and the working state of the aero-engine is obtained by using a data mining technology, and thus the monitoring of the working state of the aero-engine is realized, and the system has high accuracy, is easy to implement and has low cost.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine condition monitoring and fault diagnosis, specifically relating to a non-intrusive aero-engine condition monitoring system and its implementation method, including the overall architecture and measurement method of the system, which is suitable for condition monitoring during aero-engine ground test. Background Technology

[0002] Sensing and acquiring engine operating status is a crucial means of engine condition monitoring, as well as an important detection method for engine operation fault monitoring and engine design defect diagnosis. Traditional engine condition sensing methods, such as those based on blade vibration, gas path parameters, and gas path thermodynamic models, often require the fault to deteriorate to a certain extent before corresponding changes can be detected. Furthermore, the inherent limitations of these technologies, such as sensor installation restrictions and difficulties in signal localization, will persist for a long time.

[0003] When an aircraft engine is operating, exhaust particles acquire a certain amount of electrical charge through contact, adsorption, atomic ionization, and chemical reactions in the combustion chamber. In a healthy aircraft engine, the exhaust primarily contains soot particles, which are the result of soot formed in the main combustion zone and subsequently oxidized in the high-temperature zone. These particles have a small electrical charge, are numerous, and are relatively evenly distributed. When engine performance declines or malfunctions occur, such as blade erosion, wear-related failures in engine airflow components, or aging issues due to components reaching the end of their service life, the exhaust will contain abnormal solid particles. These abnormal particles have a large electrical charge, are few in number, and are sparsely distributed. Furthermore, as the malfunction worsens, the electrical charge of these abnormal particles gradually increases with the severity of the malfunction. Therefore, by sensing the electrical charge of the charged particles in the aircraft engine's exhaust, the operating status of the aircraft engine can be monitored.

[0004] Aero-engine condition monitoring technology based on charged particles in exhaust gas is a passive measurement method with advantages such as good linearity, strong robustness, and low cost. Existing electrostatic monitoring methods for aero-engine exhaust gas include contact electrostatic sensing and inductive electrostatic sensing methods. Contact electrostatic sensing methods typically involve deploying numerous probes, which are sensitive to charge signals at the center of the duct; however, the probes penetrating deep into the flow field can interfere with the electrostatic field, leading to measurement errors. Inductive electrostatic sensors do not directly contact charged particles, but they are insensitive to charged particles in the central region. Therefore, there is an urgent need to develop a new system for measuring the charge in aero-engine exhaust gas, providing a novel means for monitoring aero-engine operational faults. Summary of the Invention

[0005] To overcome the aforementioned problems in the prior art, this invention discloses a non-intrusive aero-engine condition monitoring system and its implementation method, and proposes a method for estimating the total charge in a closed space based on Gauss's law. The purpose of this invention is to achieve aero-engine condition monitoring by sensing the charge of charged particles in the aero-engine exhaust gas.

[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution: a non-intrusive aero-engine condition monitoring system and implementation method, wherein the monitoring system includes an exhaust gas electric field sensing device, multiple electric field sensors, a data acquisition module, and a computer; the implementation method is based on the arrangement rules of the multiple electric field sensors on the exhaust gas electric field sensing device, and calculates the real-time charge of charged particles in the exhaust gas electric field sensing device using a method for estimating the total charge in a closed space based on Gauss's theorem, and then obtains the aero-engine operating status based on the relationship between the charge of the aero-engine exhaust gas and the aero-engine operating status.

[0007] The exhaust gas electric field sensing device is installed in the vicinity of the engine exhaust nozzle, allowing the exhaust gas to flow through its center while the electric field sensor is housed inside. Since the exhaust gas contains carbon soot particles and will diffuse to some extent, a horn-shaped structure is chosen to avoid affecting the movement of these particles. The radius of the front bottom surface of the exhaust gas sensing device must take into account the influence of airflow temperature to meet the sensor's operating temperature requirements. The length of the exhaust gas sensing device needs to consider manufacturing difficulty and system accuracy. Each array of electric field sensors (m in length) is evenly distributed to form a sensing plane array, with each array plane fixed along the exhaust gas sensing device at h-meter intervals.

[0008] The multi-channel electric field sensors are installed at specific points on the exhaust gas sensing device: a spatial rectangular coordinate system is established at the center of the front bottom surface of the exhaust gas electric field sensing device, with the z-axis pointing towards the rear bottom surface. An XOY cross section with a z-coordinate interval of h meters is selected from the front bottom surface to the rear bottom surface of the exhaust gas sensing device as the electric field sensing plane to arrange the electric field sensors. Electric field sensors with similar characteristics are evenly divided into multiple groups, each group containing m sensors, and evenly arranged at m points along the edge of the aforementioned cross section. Each group of sensors is fixed to the exhaust gas electric field sensing device in a back-mounted manner. Non-contact electric field sensors are used, which have wider applicability.

[0009] The signal acquisition module includes an acquisition card with multiple channels, which can meet the signal acquisition requirements of multiple electric field sensors. The acquisition card is required to have a high frequency of use, and each channel can synchronously output the real-time acquired electric field sensor signal to the computer to complete high-precision and high-speed signal acquisition.

[0010] The computer includes a data processing and storage module, a charge soft measurement module, and a display module. The data processing and storage module receives data from the high-speed signal acquisition module. The charge soft measurement module performs signal conversion based on a Gaussian law-based method for estimating the total charge in a closed space, as proposed in this invention, converting the acquired electric field data into the required charge data. The display module displays the calculated charge data and electric field data.

[0011] The described charge measurement module is a method for estimating the total charge in a closed space based on Gauss's law. Taking into account the arrangement of 24 electric field sensors, the exhaust gas electric field sensing device is used as a closed surface. The charge within the entire closed surface is accurately and efficiently estimated using the spatial electric field values ​​measured at finite locations by the electric field sensor array. The method includes the following steps:

[0012] Step 1: Import the electric field signal from the real-time electric field sensing array on the exhaust gas sensing device;

[0013] Step 2: The exhaust gas sensor, considered as a closed curved surface, can be divided into a circular surface S1 with a front bottom radius of r, a side fan-shaped annular surface S2, and a circular surface S3 with a rear bottom radius of R, as follows: Figure 4 As shown. S1 and S2 can be obtained by multiplying the average value of the electric field sensor on the surface by its area. The fan ring S2 can be divided into n small fan rings according to the number of layers of the sensor plane array, and each small fan ring can be divided into m small regions according to the number of sensors contained in each layer of electric field sensing plane. The electric field value of each small region is approximated by the average electric field value of step one at the vertex position of the small region.

[0014] Step 3: Based on Gauss's theorem, the electric flux through any closed surface is equal to the algebraic sum of the charges within that closed surface divided by the vacuum permittivity ε0. Therefore, perform area integration of the electric field value for each small region. Finally, sum the electric flux of each part to obtain the total electric flux of the entire funnel-shaped closed surface. Multiplying this by ε0 gives the charge within the closed surface.

[0015] Furthermore, in the method for estimating the total charge in a closed space based on Gauss's law of the present invention, the calculation of the charge within the exhaust gas sensing device in step three based on Gauss's law is as follows:

[0016]

[0017] Among them, Ψ E This represents the electrical flux on the closed curved surface of the exhaust gas sensor, where S1 represents the flared front bottom surface, S3 represents the flared rear bottom surface, and S2 represents the flared side surface. E k This represents the average electric field value in each small region.

[0018]

[0019] in, ε0 represents the amount of charge within the closed curved surface of the exhaust gas sensing device, where ε0 is the vacuum permittivity.

[0020] In addition, the present invention also proposes a monitoring method based on this system, comprising the following steps:

[0021] Step 1: Place the monitoring system around the tailpipe of the aircraft engine so that the exhaust gas can flow through the exhaust gas sensing device.

[0022] Step 2: Conduct tests in five stages of normal engine operation, including the main engine slowly accelerating to 10% of its maximum speed under the drive of the auxiliary engine, engine ignition and rapid increase in speed to the maximum value, engine slowly decreasing speed, engine gradually accelerating again, and engine slowly decreasing speed until it stabilizes.

[0023] Step 3: Using the electric field value measured by the electric field sensing array, and based on the soft charge measurement method, calculate the charge in the exhaust gas sensing device from the electric field value, and measure the standard charge of the exhaust gas as the engine state changes.

[0024] Step 4: By analyzing the deviation between the charge of charged particles in the exhaust gas during engine operation and the standard charge, the status of the aero-engine can be monitored. Specifically: if the deviation exceeds a certain threshold, the engine is judged to be in a fault state; if the deviation is within the threshold, the engine is judged to be in a normal operating stage.

[0025] Compared with the prior art, the present invention has the following significant advantages:

[0026] This invention provides a non-invasive method for sensing and monitoring the condition of aero-engines, offering a novel approach to aero-engine fault diagnosis. Compared to traditional monitoring methods, this invention indirectly measures the aero-engine's condition based on exhaust gas, providing real-time performance.

[0027] The present invention proposes to estimate the charge of charged particles in exhaust gas by measuring the electric field value of exhaust gas using an electric field sensing array, thereby measuring the state of aero-engines. This method is low in cost and has high measurement accuracy.

[0028] The exhaust gas electric field sensing device proposed in this invention allows the electric field sensing array to be arranged outside the aero-engine without requiring modifications to the engine or test environment. Therefore, it is easy to implement from an engineering perspective. At the same time, the electric field sensor is arranged along the exhaust gas electric field sensing device, which can avoid the high temperature of the exhaust gas, thus reducing the requirements for the sensor and lowering the cost of the required sensor.

[0029] The method for estimating the total charge in a closed space based on Gauss's law proposed in this invention has strong applicability and is suitable for calculating the charge of charged particles in an exhaust gas electric field sensing device, with small measurement error.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the non-intrusive aero-engine condition monitoring system based on soft measurement of charged particles in exhaust gas, as per the present invention.

[0032] Figure 2 This is a schematic diagram of the system operation of the present invention;

[0033] Figure 3 This is a flowchart of the data acquisition program in this invention;

[0034] Figure 4 This is a diagram showing the estimation error of the charge quantity of charged particles in the exhaust gas in the embodiment.

[0035] Figure 5 This is a schematic diagram of the computer display module in this invention;

[0036] Figure 6 This is a schematic diagram of the method for estimating the total charge in a closed space based on Gauss's law in this invention.

[0037] Among them, 1-electric field sensor, 2-exhaust gas electric field sensing device, 3-data acquisition card, 4-computer, 5-exhaust nozzle, 6-menu bar, 7-display area for each electric field sensor value, 8-charged particle point cloud display area, 9-electric field sensor curve display area, 10-exhaust gas charged particle charge curve display area Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings.

[0039] This invention relates to a non-intrusive aircraft engine condition monitoring system, such as... Figure 1As shown, the system consists of the following parts: electric field sensor 1, exhaust gas sensing device 2, data acquisition card 3, and computer 4. The electric field sensors are arranged in groups of eight to form an electric field sensing planar array for collecting electric field signals. The exhaust gas electric field sensing device is a structure that mounts fixed electric field sensors, preferably with a front bottom radius of 1 meter and a horn-shaped angle of 8°. Each electric field planar array is evenly arranged along the exhaust gas sensing device, preferably in three layers, with each layer containing eight electric field sensors, arranged along the edge of the exhaust gas sensing device. The data acquisition card is connected to all sensors, processes and stores the sensor values, and outputs the processed electric field data to the computer. The computer stores the electric field data and uses a charge soft measurement algorithm to convert the electric field data into the required charge value. Finally, the developed software displays the charge and the corresponding electric field value.

[0040] like Figure 2 The diagram shows the overall operation of this system. The exhaust gas electric field sensing device is placed after the exhaust nozzle, with the cross-section of the exhaust nozzle aligned with the cross-sectional plane of the device, and the perpendicular bisectors of the two planes coinciding, allowing the exhaust gas flow to pass through the center of the device. When the exhaust gas flows past the device, the surrounding electric field changes due to the charged particles in the exhaust gas, causing the electric field sensor signal to change continuously. The signal acquisition module collects the signal from the electric field sensor and outputs the real-time electric field signal to the computer, where the computer performs soft measurement and display of the charge quantity.

[0041] like Figure 3 The diagram shows the data acquisition program flowchart of this invention. To implement the acquisition program, the acquisition card's acquisition program is encapsulated as a dynamic link library (DLL). The acquisition function is achieved by passing corresponding parameters to the DLL interface. Specifically, after clicking "Manual Acquisition," parameters such as the set sampling rate are passed to the DLL via a function interface, and a new array of appropriate length is created to store the data. Once the data acquisition card completes acquisition, the obtained electric field value is stored in the array. Since the acquisition time of each acquisition channel is not completely synchronized, the data in the array is synchronized and output for calculation when a set amount of data is reached, thus achieving data synchronization.

[0042] like Figure 4The diagram illustrates a calculation method for estimating the total charge in a closed space based on Gauss's law, according to the present invention. To accurately and efficiently estimate the electric flux of the entire closed surface using the spatial electric field values ​​measured at a finite number of points by an electric field sensor array, the closed surface is divided into multiple small regions. The area integral of the electric field value is performed on each small region to obtain the electric flux of each region. Finally, the electric flux of all regions is summed to obtain the total electric flux on the entire closed surface. Taking a trumpet-shaped closed surface as an example, it can be divided into a circular surface S1 on the front bottom, a fan-shaped annular surface S2 on the side, and a circular surface S3 on the rear bottom. The electric flux of S1 and S2 can be obtained by multiplying the average value of the electric field sensors on the surface by its area. The fan-shaped annular surface S2 can be divided into three small fan-shaped annular surfaces according to the number of layers of the sensor plane array. Each small fan-shaped annular surface can be divided into eight small regions according to each layer of the electric field sensor plane. The electric field value of each small region is approximated by the average electric field value of the four vertices of the region. The area integral of the electric field value is performed for each small region. Finally, by summing up the electric flux of each part, the total electric flux of the entire horn-shaped closed surface can be obtained. Multiplying this by the vacuum permittivity, the amount of charge within the closed surface can be calculated.

[0043] like Figure 5 The image shows the page structure of the display module. The software page contains five parts: the menu bar allows importing configurations and data to set the acquisition card; the upper left part is the data bar, displaying the real-time electric field value of each channel of the acquisition card; the lower left 3D stereoscopic image displays the real-time electric field point cloud map of the electric field sensing array; the two columns on the right are 2D waveform display areas, with the upper right area showing the fluctuation of the electric field value of the sensing array over time, and the lower right area showing the real-time fluctuation of the charge obtained by the soft measurement method.

[0044] like Figure 6 The diagram illustrates the measurement error of the soft measurement method for charged particles in exhaust gas. Three types of charged particles with known charge values ​​are placed at arbitrary positions on the middle cross-section of the exhaust gas sensing device. The system of this invention is used to measure the charge of the charged particles, and the relative error between the estimated and actual charge values ​​is calculated. A graph showing the relationship between the relative error and the distance of the charged particle position from the center of the cross-section is plotted. The accuracy of the total charge estimation method in a closed space based on Gauss's theorem is independent of the charge magnitude, and the method is verified to be effective. The maximum measurement error of the estimated charge is 26.15%, and the average is 11.80%. The accuracy of the charge estimated based on Gauss's theorem is related to the charge position; the closer to the center, i.e., the farther away from the sensor on the monitoring plane, the higher the accuracy.

[0045] The applicant of this invention has provided a detailed description of the specific embodiments of the invention in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above embodiments are merely preferred embodiments of the invention. The detailed description is only intended to help readers better understand the spirit of the invention and is not intended to limit the scope of protection of the invention. On the contrary, any improvements or modifications made based on the inventive spirit of the invention should fall within the scope of protection of the invention.

Claims

1. A method for implementing a non-intrusive aircraft engine condition monitoring system, characterized in that: The non-intrusive aero-engine condition monitoring system consists of four parts: an electric field sensor, an exhaust gas electric field induction device, a signal acquisition device, and a computer. The exhaust gas electric field induction device is a support that fixes the positions of the electric field sensors. The electric field sensors, as sensing units, measure the electric field value at a specific location. Multiple electric field sensors form a planar array, which is arranged along the exhaust gas electric field induction device. Exhaust gas is ejected from the exhaust nozzle and flows through the exhaust gas electric field induction device. The electric field sensors detect the electric field value near the exhaust gas, and the signal acquisition device sends the electric field value to the computer for further data processing. The implementation method involves estimating the real-time charged particle charge within the exhaust gas electric field induction device using a method based on Gauss's law for estimating the total charge in a closed space. Data mining techniques are then used to obtain the correspondence between the exhaust gas charge and the operating state of the aero-engine, thereby achieving the monitoring of the aero-engine's operating state.

2. The method for implementing the non-intrusive aero-engine condition monitoring system according to claim 1, characterized in that: The electric field sensor is a non-contact electric field sensor, which is installed on the exhaust gas electric field sensing device. It features small size, low power consumption, and high reliability, and can measure the electric field value at a certain location in a non-contact manner.

3. The method for implementing the non-intrusive aero-engine condition monitoring system according to claim 1, characterized in that: The exhaust gas electric field sensing device has a fixed electric field sensor in a funnel shape. The charged particles in the exhaust gas flow will not interfere with the sensor. The exhaust gas flow has a high temperature, and the electric field sensor is placed on the exhaust gas electric field sensing device to avoid the high temperature of the exhaust gas and ensure its normal operation. The electric field sensors form an electric field sensing planar array along the exhaust gas electric field sensing device, which can obtain the field strength at multiple locations on the exhaust gas electric field sensing device. It can restore the charge of charged particles in the exhaust gas electric field sensing device with high accuracy and low cost.

4. The implementation method of the non-intrusive aero-engine condition monitoring system according to claim 1, characterized in that: The signal acquisition device is a signal acquisition card with multiple channels. Each channel is connected to an electric field sensor, and the signal output terminal is connected to a computer. The acquisition program synchronously outputs the values ​​of the electric field sensors from each channel to the computer for processing. To implement the acquisition program, the acquisition program of the acquisition card is encapsulated as a dynamic link library. The acquisition function is realized by passing the corresponding parameters to the dynamic link library interface. Specifically, after clicking manual acquisition, the parameters are passed to the dynamic link library according to the set sampling rate parameters, and an array of the appropriate length is created to store the data. When the signal acquisition card finishes acquiring data, the obtained electric field value data is stored in the array. Since the acquisition time of each acquisition channel is not completely synchronized, the data in the array is set to be synchronously output for calculation when the data reaches a set amount, so as to achieve data synchronization.

5. The method for implementing the non-intrusive aero-engine condition monitoring system according to claim 1, characterized in that: The computer includes a data processing module, a charge soft measurement module, and a software display module. The data processing module can store the electric field signal of the signal acquisition device. The charge soft measurement module is based on the Gaussian theorem and uses a method to estimate the total charge in a closed space to convert the measured electric field value into the charge of charged particles in the exhaust gas electric field sensing device. The software display module uses developed software to display the electric field value and charge.

6. The method for implementing the non-intrusive aero-engine condition monitoring system according to claim 1, characterized in that: When the non-intrusive aero-engine condition monitoring system is working, the exhaust gas electric field sensing device is used as a closed surface. Since the electric field signal at any point on the closed surface is different, the entire closed surface is divided into multiple small regions. In each small region, the average value of the electric field signal at a limited position on the edge of the exhaust gas electric field sensing device collected by the system is used as the electric field value of the small region. Then, the electric flux of the small region is obtained by surface integration. Finally, the electric flux of the entire closed surface is obtained by summing them up. The charge of charged particles in the entire closed surface is estimated by calculation using Gauss's theorem.

7. The method for implementing the non-intrusive aero-engine condition monitoring system according to claim 5, characterized in that: The software display module's page consists of five parts: a menu bar for importing configurations and data, and for setting up the acquisition card; and a data bar in the upper left corner, which displays the real-time electric field value of each channel of the acquisition card. The lower left 3D view shows the real-time electric field point cloud map of the electric field sensing planar array; The two columns on the right are two-dimensional waveform display areas. The upper right area shows the fluctuation of the electric field value of the electric field sensing plane array over time, and the lower right area shows the real-time fluctuation of the charge obtained by the soft measurement method.

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