CN-121576901-B - High-temperature-resistant transparent shell type eddy current blade tip gap measuring device and method

Abstract

The invention discloses a high-temperature-resistant transparent shell type eddy current blade tip gap measuring device and a method, belonging to the technical field of gap measurement, wherein the device comprises a sensor probe module, a signal conditioning module, a data acquisition module and a data processing module; the sensor probe module is arranged on the outer wall of the casing and comprises a permanent magnet excitation source, a soft magnet core and a receiving coil, the signal conditioning module is electrically connected with the receiving coil and used for amplifying, filtering and integrating weak induction signals, the data acquisition module is electrically connected with the signal conditioning module and used for converting analog signals into digital signals, and the data processing module is used for processing the acquired digital signals and extracting blade tip clearance information.

Inventors

• DUAN FAJIE
• LIANG CHUNJIANG
• YE DECHAO

Assignees

• 善测（天津）科技有限公司

Dates

Publication Date

20260508

Application Date

20260128

Claims (6)

1. 1. The high-temperature-resistant transparent shell type eddy current blade tip clearance measuring device is characterized by comprising a sensor probe module, a signal conditioning module, a data acquisition module and a data processing module; the sensor probe module is arranged on the outer wall of the casing and is made of non-magnetic materials, and comprises a permanent magnet excitation source, a soft magnetic core and a receiving coil, wherein the permanent magnet excitation source generates a constant static magnetic field, magnetic lines of force penetrate through the casing wall to reach the rotating blade area; The system comprises a signal conditioning module, a data acquisition module, a data processing module, a control module and a control module, wherein the signal conditioning module is electrically connected with a receiving coil and is used for amplifying, filtering and integrating weak induction signals; The signal conditioning module comprises a preamplifier, a band-pass filter and an integrating circuit, wherein the signal conditioning module is electrically connected with the receiving coil and is used for amplifying, filtering and integrating weak induction signals; The preamplifier adopts a high-performance instrument amplifier chip to amplify mV-level weak signals output by the receiving coil to a range of 0.1-5V; the band-pass filter adopts a second-order Butterworth active filter, the passband range is 100Hz-300kHz, and the gain of the filter is 20dB; the integrating circuit adopts an RC active integrator; the data processing module comprises: the Gaussian peak detection unit is used for judging the threshold value of the acquired digital signal and identifying the peak position of the Gaussian waveform, wherein each peak corresponds to a blade passing event; The Gaussian fitting unit is used for extracting waveform data segments around each detected peak value, carrying out Gaussian function fitting, and extracting amplitude parameters as the input of gap calculation after fitting; the rotating speed calculating unit is used for calculating the rotating speed according to the time interval and the number of the blades of the passing events of the two adjacent blades; The clearance calculation unit is used for calculating the blade tip clearance through a pre-calibrated mapping relation according to the amplitude value obtained by Gaussian fitting and the rotating speed obtained by rotating speed calculation; And the data output and display unit is used for outputting the clearance value, the rotating speed and the time stamp of each blade in real time, displaying the clearance value, the rotating speed and the time stamp in the form of numerical values, waveforms and trend curves, and recording and storing data.
2. 2. The high-temperature-resistant transparent shell type eddy current blade tip gap measuring device according to claim 1, wherein the permanent magnet excitation source is a samarium cobalt permanent magnet or a neodymium iron boron permanent magnet, the shape is cylindrical, the magnetization direction is axial, and the magnetic induction intensity of the permanent magnet excitation source is 200-500mT; the soft magnetic core is made of permalloy or ferrite material, and has a relative magnetic permeability of mu r not less than 10,000 and a temperature resistance of not less than 350 ℃; The receiving coil is wound on the soft magnetic core by adopting an enamelled copper wire, the wire diameter of the enamelled copper wire is 0.1-0.3mm, the number of turns is 500-3000 turns, the inductance is 50-200mH, and the direct current resistance is 200-800 omega.
3. 3. The high temperature resistant transparent shell type eddy current tip clearance measurement apparatus of claim 1, wherein the sensor probe module further comprises a cooling system and a shielding device; The cooling system adopts an air path cooling mode, and cools the soft magnetic core and the receiving coil through compressed air, and the shielding device comprises a stainless steel shell for packaging the sensor probe module, an electromagnetic shielding layer is arranged for reducing external electromagnetic interference, and a twisted pair or a coaxial cable is adopted for outputting signals.
4. 4. The high-temperature-resistant transparent shell type eddy current blade tip clearance measuring device according to claim 1, wherein the data acquisition module comprises a high-speed analog-to-digital converter and a data buffering and communication interface, and is electrically connected with the signal conditioning module to convert analog signals into digital signals; the high-speed analog-to-digital converter adopts a continuous sampling mode to continuously collect the integrated Gaussian signal waveform data; The data buffering and communication interface adopts an FPGA or a high-performance MCU to perform data buffering and preprocessing, and transmits digital signals to the upper computer through the Ethernet interface; and the data package of the data acquisition module adopts a UDP protocol.
5. 5. A high temperature resistant transparent shell type eddy current tip clearance measuring method according to any one of claims 1 to 4, characterized by comprising the steps of: Establishing a casing and rotating blade calibration system, collecting Gaussian signal amplitude values output by a sensor under different rotating speeds and different clearance conditions, and establishing a mapping relation of the rotating speed, the amplitude value and the clearance based on the Gaussian signal amplitude values; The sensor probe module is arranged on the outer wall of the casing, and the Gaussian signals after amplification, filtering and integration are continuously obtained through the signal conditioning module; The data processing module performs peak detection, gaussian fitting and rotation speed calculation on the real-time digital signal flow, calculates a blade tip clearance by using the mapping relation of the rotation speed, the amplitude and the clearance and outputs a measurement result; The sensor probe module is arranged on the outer wall of the casing, the Gaussian signals after amplification, filtering and integration processing are continuously obtained through the signal conditioning module, the data acquisition module acquires the waveform data of the Gaussian signals after integration, and the acquisition of the real-time digital signal stream comprises the following steps: the sensor probe module is arranged on the outer wall of the casing, so that the front end of the probe is tightly attached to the casing wall, the axis of the probe is perpendicular to the casing wall, and the probe is aligned with the scanning area of the blade; Starting a signal conditioning module, setting the sampling rate of the ADC to be more than or equal to 1MSPS, and setting the sampling mode to be continuous sampling; The signal conditioning module continuously collects induction signals output by the receiving coil, the signals are processed by a pre-amplifier, a band-pass filter and an integrating circuit to obtain Gaussian signals, the gain of the pre-amplifier is 40-60dB, the frequency of the band-pass filter is 100Hz-300kHz, and the time constant of the integrating circuit is 5-10 mu s; The data acquisition module acquires the integrated Gaussian signal waveform data to obtain a real-time digital signal stream, and the real-time digital signal stream is buffered by the FPGA/MCU and then transmitted to the data processing module; The data processing module performs peak detection, gaussian fitting and rotation speed calculation on the real-time digital signal stream, and the calculating of the tip clearance and the outputting of the measurement result by using the rotation speed-amplitude-clearance mapping relation comprises the following steps: The data processing module receives the real-time digital signal stream and processes the real-time digital signal stream, and firstly carries out digital filtering to remove high-frequency noise; the method comprises the steps of carrying out threshold judgment on an acquired digital signal, detecting the Gaussian peak position, setting a threshold value by adopting a 3 sigma criterion, judging the signal amplitude to be an effective Gaussian peak when the signal amplitude exceeds the threshold value and meets the condition of local maximum value, and recording the peak index and the time stamp; extracting a single Gaussian waveform data segment corresponding to each peak value, and collecting a preset second threshold value sampling point; carrying out Gaussian function fitting on a single Gaussian waveform, namely adopting a nonlinear least square method to carry out fitting, and extracting amplitude parameters, peak value centers and widths after fitting; calculating a fitting goodness R 2 ; calculating the rotating speed according to the time interval and the number of blades of two adjacent peaks; Substituting the amplitude and the rotating speed into a calibration relation to calculate the tip clearance, namely adopting a bilinear interpolation method to search four adjacent points according to the calibration table and calculating the tip clearance according to an interpolation formula; outputting a measurement result, wherein the measurement result comprises a blade number, a blade tip gap, a rotating speed, a time stamp and a fitting goodness R 2 ; Carrying out statistical analysis on the clearance values of a plurality of blades in each circle, calculating the mean value and the standard deviation, and eliminating abnormal values exceeding the range of +/-3 sigma; The real-time display of the measurement results comprises numerical display of the current rotating speed and the clearance value of each blade, waveform display of the original signal waveform, the integrated Gaussian signal waveform and a fitting curve, trend curve of the clearance trend or the change trend of the rotating speed, alarm according to the preset alarm rule; all measured data is recorded and stored for subsequent fault diagnosis, life prediction and performance assessment.
6. 6. The high-temperature-resistant transparent shell type eddy current blade tip clearance measurement method is characterized in that the machine box and rotating blade calibration system comprises a high-speed rotating platform, a precise displacement platform and a simulation machine box, wherein the rotating speed range of the high-speed rotating platform is 0-30,000rpm, the rotating speed precision is +/-0.1%, the stroke of the precise displacement platform is more than or equal to 10mm, the positioning precision is less than or equal to 5 mu m, the simulation machine box is made of the same material as an actual machine box, and the thickness of the simulation machine box is 3-8mm; The construction steps of the construction machine case and rotating blade calibration system comprise: a blade simulation piece is arranged on a high-speed rotating table, the number of the blades is 6-12, and the material is titanium alloy or stainless steel; setting a plurality of rotating speed points, wherein the rotating speed range covers the actual working range of 0-30,000rpm; setting a plurality of clearance points, wherein the clearance range covers the measurement range by 0.5-5mm; the acquisition of Gaussian signal amplitude values output by the sensor under different rotating speeds and different clearance conditions comprises the following steps: for each speed-gap combination, the following operations are performed: Setting the rotating speed of the rotating table as ni, and waiting for a first preset time period; The precise displacement table moves to a gap position dj and waits for a second preset time period; repeatedly measuring the first preset times for several times, collecting first preset number of blade passing events each time, and recording corresponding Gaussian signal amplitude values; the establishing a mapping relation between the rotating speed and the amplitude and the gap based on the Gaussian signal amplitude comprises the following steps: establishing a rotating speed-amplitude-gap three-dimensional mapping relation table, and storing all calibration data points; calibration verification, namely selecting 5-10 intermediate points which do not participate in calibration, actually measuring and comparing with a theoretical value, and requiring errors; The calculated average amplitude and standard deviation are obtained.

Description

High-temperature-resistant transparent shell type eddy current blade tip gap measuring device and method Technical Field The invention belongs to the technical field of gap measurement, and particularly relates to a high-temperature-resistant transparent shell type eddy current blade tip gap measurement device and method. Background Tip clearance refers to the radial clearance between the top end of a rotating blade of an aero-engine turbine and the inner wall of a casing, and is a key parameter affecting engine performance, efficiency and reliability. Too large a tip clearance can cause air leakage and reduce engine efficiency and thrust, while too small a tip clearance can cause blade and casing rub, causing blade damage and even catastrophic failure. Studies have shown that every 0.25mm increase in tip clearance, engine efficiency decreases by about 1% and fuel consumption increases by about 1.5%. Therefore, accurate measurement of tip clearance is of great importance for engine performance optimization, condition monitoring and fault diagnosis. The prior art mainly comprises a capacitance type measuring method, an optical fiber type measuring method, a microwave/millimeter wave measuring method and an electric vortex measuring method, wherein the capacitance formed between a blade and a sensor is used for measuring along with the change of the gap, the sensor is required to be installed on a casing through an opening, the structural integrity of the casing is damaged, the influence of temperature and oil stains is large, the optical fiber type measuring method comprises the steps of radiating the blade through an optical fiber probe, calculating the gap according to reflected light intensity or flight time, enabling an optical window to be easily polluted, and the reliability under high-temperature, high-speed and vibration environments is poor, the microwave/millimeter wave measuring method is used for measuring the gap by using the electromagnetic wave reflection principle, the system is complex, the cost is high, the space resolution is low, the electric vortex sensor is installed on the inner wall of the casing, the blade tip gap is directly measured, and the electric vortex sensor is exposed in the severe environments with high temperature and high pressure, the service life is short, and maintenance is difficult. The common disadvantages of the prior art are that the sensors are required to be installed on the casing through holes or grooves, the structural integrity and the pneumatic tightness of the casing are damaged, the installation difficulty and the maintenance cost are increased, and the sensors are required to be installed in the casing to face extreme working environments such as high temperature (600-1000 ℃), high pressure, high-speed airflow and strong vibration, so that the reliability and the service life of the sensors are difficult to guarantee. Therefore, a high-temperature-resistant transparent shell type eddy current blade tip clearance measuring device and method are needed to solve the technical problems that a casing is required to be perforated, a sensor is poor in working environment and poor in reliability. Disclosure of Invention The invention aims to provide a transparent shell type eddy current blade tip clearance measurement device and method, which are used for solving the problems that in the prior art, a casing is required to be perforated, the working environment of a sensor is bad, the reliability is poor and the like, and realizing the blade tip clearance measurement with non-contact, transparent shell, high precision and high reliability. The invention aims to provide a high-temperature-resistant transparent shell type eddy current blade tip clearance measuring device which comprises a sensor probe module, a signal conditioning module, a data acquisition module and a data processing module, wherein the sensor probe module is connected with the sensor probe module; The sensor probe module is arranged on the outer wall of the casing and is made of non-magnetic materials, and comprises a permanent magnet excitation source, a soft magnetic core and a receiving coil, wherein the permanent magnet excitation source generates a constant static magnetic field, magnetic lines of force penetrate through the casing wall to reach the rotating blade area, the soft magnetic core is arranged in the radiation direction of the magnetic field of the permanent magnet excitation source and is separated from the permanent magnet excitation source and used for guiding the magnetic field and serving as a magnetic core of the receiving coil, and the receiving coil is used for inducing a secondary magnetic field to generate induction voltage; The system comprises a signal conditioning module, a data acquisition module, a data processing module and a control module, wherein the signal conditioning module is electrically connected with a receiving coil and used for amplifying, filtering an