Dispersion interferometry rotor-stator blade tip clearance measurement device and method based on blade tip pulse signal triggering

Abstract

The present invention discloses a dispersion interferometric rotor-stator blade tip clearance measurement device and method based on blade tip pulse signal triggering, which belongs to the field of engine detection technology. The device includes a wide-spectrum light source, a circulator, an optical fiber sensor, a coupler, a spectrometer optical path module, a CCD, a gap resolution module, a photodetector, and a CCD trigger module. The wide-spectrum light source, the circulator, and the optical fiber sensor are connected in sequence; after the circulator is connected to the coupler, it is divided into two paths, one path passes through the spectrometer optical path module and the CCD in sequence and then enters the gap resolution module, and the other path passes through the photodetector and enters the CCD trigger module; the CCD trigger module is connected to the CCD to provide a trigger signal for it. The present invention can extract the light intensity of the optical fiber gap sensing signal and shape it as a CCD integral trigger signal to control the start and end time of the CCD integral, so that the integral is synchronized with the blade arrival time, thereby improving the accuracy of the gap measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of engine detection, and in particular to a dispersion interferometry rotor-stator blade tip clearance measurement device and method based on blade tip pulse signal triggering. Background Art

[0002] The state parameters of the core components of aircraft engines (rotors, moving blades, etc.) directly affect the operating state, work efficiency and safety performance of the equipment. In particular, the change in the radial clearance between the rotor and the stator is one of the main factors affecting the performance and safety of the equipment. In order to improve the performance and efficiency of the equipment, closed-loop active clearance control has become an important development direction, and online monitoring of the rotor-stator clearance is a prerequisite for realizing active clearance control. The frequency domain interferometric rotor-stator clearance measurement method is an effective clearance measurement method developed in recent years. It uses the probe end face return light to interfere with the reflected light of the measured surface, and analyzes the spectrum of the interference light intensity through a spectrometer to achieve clearance measurement. It has the advantages of small probe size, high measurement accuracy and strong anti-interference ability. However, limited by the frame rate of the spectrometer, the maximum measurement frequency of this method is only tens of kilohertz. If the object to be measured is a rotating blade, the system may not be able to capture the signal in time when the blade reaches the sensor, resulting in measurement loss.

[0003] Therefore, when measuring the rotor-stator blade tip clearance, a dispersion interferometry rotor-stator blade tip clearance measurement device and method based on blade tip pulse signal triggering is needed to capture the signal in time to make the clearance measurement more accurate. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for measuring the rotor-stator blade tip clearance based on a dispersion interferometric method triggered by a blade tip pulse signal.

[0005] A dispersion interferometric rotor-stator blade tip gap measuring device based on blade tip pulse signal triggering comprises a wide-spectrum light source, a circulator, an optical fiber sensor, a coupler, a spectrometer optical path module, a CCD, a gap resolution module, a photoelectric detector, and a CCD trigger module. The wide-spectrum light source, the circulator, and the optical fiber sensor are connected in sequence; after the circulator is connected to the coupler, the circulator is divided into two paths, one path passes through the spectrometer optical path module and the CCD in sequence and then enters the gap resolution module, and the other path passes through the photoelectric detector and enters the CCD trigger module; the CCD trigger module is connected to the CCD to provide a trigger signal for it.

[0006] The inner core of the optical fiber sensor uses a pigtail with a PC end face, and the end face is perpendicular to the optical axis.

[0007] The invention discloses a measuring method of a dispersion interference rotor-stator blade tip clearance measuring device triggered by a blade tip pulse signal. The laser emitted by a wide-spectrum light source reaches a circulator through an optical fiber, and then reaches a fiber sensor through an optical fiber. A part of the laser is directly reflected from the end face of the fiber sensor as a reference light, and another part of the laser passes through the fiber sensor as a measuring light. The measuring light passes through the gap space and irradiates the radial end face of the rotor. Part of the reflected measuring light is received by the fiber sensor, passes through the fiber sensor again and is coupled into the original fiber. At this time, the reflected measuring light and the reference light interfere with each other to form interference light. The interference light passes through the circulator again and reaches the coupler, and is divided into two beams of light by the coupler. One beam of light enters the optical path module of the spectrometer and is split and irradiated onto the CCD to be received, and the other beam of light reaches the photodetector. The photodetector converts the gap sensing light signal into an electrical signal and transmits it to the CCD trigger module. The CCD trigger module extracts its pulse envelope after filtering, amplifying and conditioning the electrical signal. An integration start trigger signal and an integration stop trigger signal are transmitted to the CCD according to the pulse envelope, so as to control the start and end time of the CCD integration. The CCD integration output signal is transmitted to the gap solving module to solve the gap.

[0008] The beneficial effects of the present invention are as follows: the device and method proposed in the present invention extract the light intensity of the optical fiber gap sensing signal and shape it as a CCD integration trigger signal to control the start and end time of the CCD integration, so that the integration is synchronized with the blade arrival time, thereby improving the accuracy of the gap measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural schematic diagram of the device for measuring rotor-stator blade tip clearance based on the dispersion interferometry triggered by the blade tip pulse signal of the present invention;

[0010] Figure 2 Schematic diagram of CCD synchronous trigger integration. DETAILED DESCRIPTION

[0011] The present invention proposes a device and method for measuring rotor-stator blade tip clearance based on a dispersion interferometric method triggered by a blade tip pulse signal. The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0012] Figure 1 The schematic diagram of the structure of the dispersion interferometric rotor-stator blade tip clearance measurement device based on blade tip pulse signal triggering is shown in Figure 1. The device includes a wide-spectrum light source, a circulator, a fiber optic sensor, a coupler, a spectrometer optical path module, a CCD, a gap resolution module, a photodetector, and a CCD trigger module. The wide-spectrum light source, the circulator, and the fiber optic sensor are connected in sequence; after the circulator is connected to the coupler, it is divided into two paths, one path passes through the spectrometer optical path module and CCD in sequence and then enters the gap resolution module, and the other path passes through the photodetector and enters the CCD trigger module; the CCD trigger module is connected to the CCD to provide it with a trigger signal.

[0013] During the gap measurement process, the broad spectrum laser generated by the broad spectrum light source reaches the circulator through the optical fiber, and then reaches the optical fiber sensor through the optical fiber. Part of the laser is directly reflected from the end face of the optical fiber sensor as the reference light, and most of the laser passes through the optical fiber sensor as the measurement light. The inner core of the optical fiber sensor uses a PC end face pigtail, whose end face is perpendicular to the optical axis, so it can enhance the intensity of the reflected light from the end face of the optical fiber sensor, that is, the reference light. After the measurement light passes through the optical fiber sensor, it passes through a distance of The reflected light from the radial end face of the rotor is received by the optical fiber sensor, passes through the optical fiber sensor again, and is coupled into the original optical fiber. At this time, the reflected measurement light and the reference light interfere with each other. The interference light passes through the circulator again and reaches the coupler, where it is divided into two beams of light. One beam of light enters the optical path module of the spectrometer and is split and irradiated onto the CCD to be received, while the other beam of light reaches the photodetector PD. PD converts the optical signal into an electrical signal and transmits it to the CCD trigger module. The CCD trigger module filters, amplifies, and conditions the gap sensor signal and then extracts its pulse envelope, such as Figure 2 As shown. In addition, the integration start trigger signal and the integration stop trigger signal are transmitted to the CCD according to the gap sensing signal pulse envelope, thereby controlling the CCD integration start and end time. The CCD integration output signal is transmitted to the gap calculation module, and the tip gap is calculated according to the frequency domain interference absolute distance measurement principle, thereby realizing the tip gap measurement.

[0014] The present invention can extract the optical fiber gap sensing signal intensity and shape it as a CCD integration trigger signal to control the CCD integration start and end time, so that the integration is synchronized with the blade arrival time, thereby improving the accuracy of gap measurement.

Claims

1. A measuring method of a dispersion interferometric rotor-stator blade tip clearance measuring device based on blade tip pulse signal triggering, the device comprising a wide spectrum light source, a circulator, an optical fiber sensor, a coupler, a spectrometer optical path module, a CCD, a clearance solving module, a photoelectric detector, and a CCD trigger module, characterized in that: The wide-spectrum light source, circulator, and optical fiber sensor are connected in sequence; after the circulator is connected to the coupler, it is divided into two paths, one path passes through the spectrometer optical path module and CCD in sequence and then enters the gap resolution module, and the other path passes through the photoelectric detector and enters the CCD trigger module; The CCD trigger module is connected to the CCD to provide a trigger signal for it; The laser emitted by the wide-spectrum light source reaches the circulator through the optical fiber, and then reaches the optical fiber sensor through the optical fiber. A part of the laser is directly reflected from the end face of the optical fiber sensor as reference light, and the other part of the laser passes through the optical fiber sensor as measurement light; the measurement light passes through the gap space and irradiates the radial end face of the rotor, and part of the reflected measurement light is received by the optical fiber sensor, passes through the optical fiber sensor again and is coupled into the original optical fiber; at this time, the reflected measurement light and the reference light interfere with each other to form interference light; the interference light passes through the circulator again to reach the coupler, and is divided into two beams of light by the coupler, one of which enters the optical path module of the spectrometer to be split and irradiated onto the CCD to be received, and the other beam of light reaches the photodetector, which converts the gap sensing light signal into an electrical signal and transmits it to the CCD trigger module, which filters, amplifies and conditions the electrical signal and extracts its pulse envelope; an integration start trigger signal and an integration stop trigger signal are emitted to the CCD according to the pulse envelope, thereby controlling the start and end time of the CCD integration; The CCD integral output signal is transmitted to the gap calculation module to calculate the gap.

2. According to claim 1, the measuring method of the dispersion interferometry rotor-stator blade tip clearance measuring device based on blade tip pulse signal triggering is characterized in that: The inner core of the optical fiber sensor uses a pigtail with a PC end face, and the end face is perpendicular to the optical axis.

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