CN210533292U - Rotor and stator axial clearance online measurement system based on Fizeau common-path structure - Google Patents
Rotor and stator axial clearance online measurement system based on Fizeau common-path structure Download PDFInfo
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- CN210533292U CN210533292U CN201920820092.6U CN201920820092U CN210533292U CN 210533292 U CN210533292 U CN 210533292U CN 201920820092 U CN201920820092 U CN 201920820092U CN 210533292 U CN210533292 U CN 210533292U
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Abstract
The utility model relates to a non-contact range finding field for providing a rotor stator axial clearance on-line measuring system based on fexol common optical path structure. The system realizes non-contact real-time online accurate measurement of the axial clearance of the rotor and the stator of the aircraft engine under the conditions of high temperature and limited space by designing a Fizeau common-path interference structure and a small-size high-temperature-resistant optical fiber sensor, monitors the running state of the rotor and the stator of the engine, and provides a basic data source for the optimal design and control of the axial clearance of the rotor and the stator of the modern aircraft engine. Therefore, the utility model discloses, rotor stator axial clearance on-line measuring system based on fexole common optical path structure, include: the device comprises a sweep frequency light source, an optical fiber, a coupler, a circulator, an optical fiber probe, a photodiode, a signal conditioning module, a signal acquisition module, a coupler, an optical fiber delayer, a balance receiving module, a zero-crossing detection module and a controller. The utility model discloses mainly be applied to non-contact range finding occasion.
Description
Technical Field
The utility model belongs to the technical field of non-contact range finding and specifically relates to an aeroengine rotor stator axial clearance measures the field.
Background
The aircraft engine is called pearl on the industrial crown, is the heart of an aircraft, and is one of the bottlenecks restricting the development of the aviation industry in China. Modern aircraft engines are developing towards high thrust-weight ratio, high supercharging ratio and high turbine front temperature, and engine core components work in extreme states, wherein axial movement between rotors and stators is one of important factors influencing engine performance and safety. In the transition state of the operation state, the aero-engine bears the action of a plurality of nonlinear excitation sources, so that the rotor and stator components of the aero-engine are directly deformed and axially moved, and the axial clearance between a casing and a rotor, between a sealing comb tooth and a blade and between a moving blade grid and a static blade grid is changed. Meanwhile, the temperature distribution inside the engine is not uniform, and a rotor and stator system rotating at a high speed generates non-uniform temperature stress and non-uniform thermal expansion, so that axial movement is generated between the rotor and the stator. The common coupling of the above two factors directly causes the axial clearance between the rotor and the stator of the aircraft engine to change greatly, even exceeding 10mm under extreme conditions. When the rotor and the stator move greatly in the axial direction, the engine can be damaged, and huge economic loss is caused and even personal safety is threatened. In addition, researches show that when the axial clearance inside the air compressor of the aircraft engine is reduced from large to small, the potential flow interference between blade rows is enhanced, the diffusion capacity is improved, and the efficiency of the engine can be obviously improved. Meanwhile, modern aircraft engines are developing towards the direction of compact arrangement of the interstage, and the optimal design of the axial clearance can effectively improve the efficiency and the performance of the engines.
The problems of high measurement environment temperature (300 ℃/450 ℃) and narrow measurement space, complex signal wire leading-out path, large measurement range (the blade tip clearance range is generally about 3mm, the axial clearance range is generally about 10 mm), high measurement precision requirement, narrow sensor installation space and the like exist in the measurement process of the rotor-stator axial clearance of the aircraft engine, and no effective rotor-stator axial clearance measurement means exists up to now. The dynamic change rule of the axial clearance between the rotor and the stator of the aero-engine is not clear, and the data loss caused by the dynamic change rule becomes one of the bottlenecks which restrict the optimization design and the operation safety monitoring of the aero-engine. The axial clearance of the rotor and the stator of the aircraft engine is listed as an important optimization and control parameter of the modern aircraft engine design. Therefore, the non-contact real-time online accurate measurement of the rotor and stator axial clearance of the aircraft engine is not only crucial to the health monitoring of the rotor and stator running state of the aircraft engine, but also can provide an important basic data source for the optimal design and control of the rotor and stator axial clearance of the modern advanced aircraft engine.
Disclosure of Invention
For overcoming the deficiencies of the prior art, the utility model aims at providing a rotor-stator axial clearance on-line measuring system based on the structure of the common light path of the Fizeau. The system realizes non-contact real-time online accurate measurement of the axial clearance of the rotor and the stator of the aircraft engine under the conditions of high temperature and limited space by designing a Fizeau common-path interference structure and a small-size high-temperature-resistant optical fiber sensor, monitors the running state of the rotor and the stator of the engine, and provides a basic data source for the optimal design and control of the axial clearance of the rotor and the stator of the modern aircraft engine. Therefore, the utility model discloses the technical scheme who takes is, based on the rotor stator axial gap on-line measuring system of the common light path structure of fexole, include: the device comprises a sweep frequency light source, an optical fiber, a coupler, a circulator, an optical fiber probe, a photodiode, a signal conditioning module, a signal acquisition module, a coupler, an optical fiber delayer, a balance receiving module, a zero-crossing detection module and a controller;
the sweep frequency light source emits sweep frequency laser which is coupled into the input end of the coupler through the optical fiber; the first output end of the coupler is connected with the input end of the circulator through an optical fiber; the first output end of the circulator is connected with the optical fiber probe through an optical fiber; the surface of the optical fiber probe is specially processed, so that one part of the sweep frequency laser is emitted to the surface of a measured object and reflected, the other part of the sweep frequency laser is directly reflected on the surface of the optical fiber probe, the reflected light on the surface of the measured object is interfered with the reflected light on the surface of the optical fiber probe, the sweep frequency laser returns to the first output end of the circulator through the optical fiber and is transmitted out from the second output end of the circulator, and an interference optical signal is transmitted out from the second output end of the circulator and then is received by the photodiode through the optical; the photodiode receives the interference light signal to generate an electric signal, and transmits the electric signal to the first signal conditioning module, and the first signal conditioning module conditions the electric signal and transmits the conditioned electric signal to the signal acquisition module; the second output end of the coupler enters the input end of the first coupler through the optical fiber; the first output end of the first coupler is connected with the optical fiber delayer through an optical fiber; the second output end of the first coupler is connected with the first input end of the second coupler through an optical fiber; the output end of the optical fiber delayer is connected with the second input end of the second coupler through an optical fiber; the two paths of optical signals interfere in the second coupler and are received by the balanced receiving module, and the optical signals received by the balanced receiving module are conditioned by the second signal conditioning module; the signal conditioned by the second signal conditioning module enters a zero-crossing comparator to generate sampling clock signals with equal k intervals; the sampling clock signals with equal k intervals generated by the zero-crossing comparator drive the signal acquisition module; the signal collected by the signal collection module is output through the controller control.
The controller controls the sweep frequency light source 1 and the second acquisition module.
The device also comprises an upper computer, the controller controls the output signal to estimate the frequency of the interference signal through Fourier transform by the upper computer, and non-contact online measurement of rotor and stator axial gap signals is realized according to the formula (1), wherein X (k) is rotor and stator gap measurement value, x (n) is collected interference signal, k is discrete frequency position, and n is discrete time position:
the frequency sweep light source adopts a common equal frequency interval frequency sweep light source or an equal wavelength interval frequency sweep light source; the optical fiber is a mode optical fiber; the coupler adopts a common optical fiber splitter; the circulator can adopt a polarization-maintaining three-port optical circulator, an optical fiber circulator and an optical fiber three-port circulator; the circulator functions to transmit the interference optical signal to the photodiode but not to the coupler.
The optical fiber probe can adopt a graded index lens or a sensor structure of an optical fiber and a quartz lens, a weak reflection film is plated on the end face of the optical fiber, the circulator, the optical fiber probe and the optical fiber between the circulator and the optical fiber probe form a Fizeau interference structure, a reference light signal reflected by the end face of the optical fiber probe and a reflected light signal at the side face of the optical fiber probe are transmitted in the same optical fiber, and temperature drift and phase jitter caused by temperature drift and vibration are counteracted; the interference signal is transmitted to the photodiode when it reaches the circulator.
The photodiode can adopt an avalanche photodiode or a PIN diode; the first signal conditioning module can be composed of a transimpedance amplifying circuit and a filter circuit; the signal acquisition module can adopt an analog-digital conversion module; the coupler can adopt an optical fiber splitter, the optical fiber delayer selects a single-mode optical fiber or a multi-mode optical fiber with optical path difference, the equivalent optical path difference of the optical fiber extender is s, and the equivalent optical path difference of the axial distance is s0Then s is less than or equal to s0。
The balanced receiving module can be composed of two groups of photodiodes and a transimpedance amplifying circuit.
The utility model discloses a characteristics and beneficial effect are:
adopt the utility model provides a rotor stator axial clearance on-line measuring system based on fexole is light path structure altogether can obtain following beneficial effect:
1) the rotor and stator axial clearance online measurement system based on the Fizeau common-path structure realizes the online measurement of the rotor and stator axial clearance of the engine under the extreme service condition by designing the small-size and high-temperature-resistant optical fiber probe.
2) The rotor-stator axial clearance online measurement system based on the Fizeau common-path structure has the advantages that the Fizeau common-path interference structure is designed, so that sweep frequency optical signals are interfered firstly and then transmitted, temperature drift and phase jitter generated in the transmission process of optical signals can be eliminated, and the clearance measurement precision is improved.
Description of the drawings:
FIG. 1 shows an on-line measurement system for rotor and stator axial clearance based on Fizeau common-path structure
In fig. 1, 1 is a swept-frequency light source, 2 is an optical fiber, 3 is a coupler, 4 is a circulator, 5 is an optical fiber probe, 6 is a photodiode, 7 is a signal conditioning module, 8 is a signal acquisition module, 9 is a 3dB coupler, 10-bit optical fiber delayer, 11 is a balanced receiving module, 12 is a zero-crossing detection module, 13 is a controller, and 14 is an upper computer.
Detailed Description
In order to realize the utility model discloses the purpose, the online measurement system of rotor and stator axial clearance based on fexol common optical path structure that proposes, as shown in fig. 1, include: the device comprises a sweep frequency light source 1, an optical fiber 2, a coupler 3, a circulator 4, an optical fiber probe 5, a photodiode 6, a signal conditioning module 7, a signal acquisition module 8, a 3dB coupler 9, an optical fiber delayer 10, a balanced receiving module 11, a zero-crossing detection module 12, a controller 13 and an upper computer 14.
A rotor-stator axial clearance online measurement system based on a Fizeau common-path structure is disclosed, wherein a sweep frequency light source 1 emits sweep frequency laser, and the sweep frequency laser is coupled into an input end of a coupler 3 through an optical fiber 2.
Further, a first output of the coupler 3 is connected to an input of the circulator 4 via the optical fiber 2.
Further, the first output end of the circulator 4 is connected with the fiber probe 5 through the optical fiber 2.
Furthermore, the surface of the fiber probe 5 is specially processed, so that one part of the sweep laser is emitted to the surface of the object to be measured and reflected, and the other part of the sweep laser is directly reflected on the surface of the fiber probe 5.
Further, the reflected light from the surface of the object to be measured interferes with the reflected light from the surface of the fiber probe 5, returns to the first output end of the circulator 4 through the optical fiber 2, and is transmitted out from the second output end of the circulator 4.
Further, the interference optical signal is transmitted from the second output end of the circulator 4 and then received by the photodiode 6 via the optical fiber 2.
Further, the photodiode 6 receives the interference light signal and generates an electrical signal, which is transmitted to the signal conditioning module 7.
Further, the signal conditioning module 7 conditions the electrical signal and transmits the conditioned electrical signal to the signal acquisition module 8.
Further, a second output of the coupler 3 enters the input of the first 3dB coupler 9 via the optical fiber 2.
Further, the first output of the first 3dB coupler 9 is connected to the fiber delay 10 via the fiber 2.
Further, a second output of the first 3dB coupler 9 is connected to a first input of the second 3dB coupler 9 via the optical fiber 2.
Further, the output of the fiber delay 10 is connected to the second input of the second 3dB coupler 9 via the fiber 2.
Further, the two optical signals interfere at the second 3dB coupler 9 and are received by the balanced receiving module 11.
Further, the optical signal received by the balanced receiving module 11 is conditioned by the signal conditioning module 8.
Further, the signal conditioned by the signal conditioning module 8 enters the zero-crossing comparator 12 to generate the sampling clock signals with equal k intervals.
Further, the sampling clock signals of equal k intervals generated by the zero-crossing comparator 12 drive the signal acquisition module 8.
Further, the signal collected by the signal collection module 8 is transmitted to the upper computer 14 via the controller 13.
Further, the controller 13 may control the swept-frequency light source 1.
Further, the controller 13 may control the signal acquisition module 8.
Further, the upper computer 14 estimates the frequency of the interference signal through fourier transform, and realizes non-contact on-line measurement of the rotor and stator axial gap signal according to the formula (1). Where X (k) is the rotor-stator gap measurement and x (n) is the interference signal collected. Where k is the discrete frequency location and n is the discrete time location.
Further, the swept source 1 may be a common constant frequency interval swept source or a common constant wavelength interval swept source. Such as with an equi-frequency spaced swept source.
Further, the optical fiber 2 may be an optical fiber or a multimode optical fiber. Such as using single mode optical fibers.
Further, the coupler 3 may employ a common fiber optic splitter. For example, an optical fiber splitter with a splitting ratio of 1:4 is adopted, and the first output port is divided into 80% of light intensity, and the second output port is divided into 20% of light intensity.
Further, the circulator 4 may employ a common polarization maintaining three-port optical circulator, a fiber optic circulator, a fiber three-port circulator, or the like. Such as with a fiber optic circulator. The circulator 4 functions to transmit the interference optical signal to the photodiode 6, but not to the coupler 3.
Further, the optical fiber probe 5 can adopt a graded index lens or a sensor structure of an optical fiber and a quartz lens, and a weak reflection film is plated on the end face of the optical fiber. For example, a sensor structure of optical fiber + quartz lens is adopted, and a weak reflection film is plated on the end face of the optical fiber. This structure has several advantages: enabling a portion of the optical signal to be reflected at the end face and another portion to be emitted laterally and interfere at the end face; the rotor and stator axial clearance measurement device can resist 450 ℃ high temperature and realize the measurement of the rotor and stator axial clearance under the condition of extremely short service of an engine.
Furthermore, the circulator 4, the optical fiber probe 5 and the optical fiber 2 between the circulator 4 and the optical fiber probe 5 form a fizeau interference structure, and a reference light signal reflected at the end face of the optical fiber probe 5 and a reflected light signal at the side face propagate in the same optical fiber, so that temperature drift and phase jitter caused by temperature drift, vibration and the like can be counteracted. Meanwhile, the interference signal reaches the circulator 4 and is transmitted to the photodiode 6. The utility model discloses a high temperature resistant fizeau interference structure suitable for engine rotor stator field of measurement can realize the high accuracy on-line measuring of engine rotor stator.
Further, the photodiode 6 may employ a common avalanche photodiode or PIN diode or the like. Such as a PIN diode.
Further, the signal conditioning module 7 may be composed of a transimpedance amplification circuit and a filter circuit. Such as a transimpedance amplifier circuit and a second-order active band-pass filter designed based on a high-precision and high-speed budget amplifier OPA 847.
Further, the signal acquisition module 8 may adopt an analog-digital conversion module. Such as a high-speed acquisition card designed based on an FPGA model EP4CE622C 8N.
Further, the 3dB coupler 9 may employ a conventional fiber optic splitter. For example, a fiber optic splitter with a splitting ratio of 1:1 is used.
Further, the fiber retarder 10 may be a single mode fiber or a multimode fiber with a certain optical path difference. Let the equivalent optical path difference of the optical fiber extender 13 be s, and the axial distance equivalent optical path difference be s0Then s is less than or equal to s0min. If the equivalent optical path difference is s ═ s0minA single mode optical fiber of/2.
Further, the balanced receiving module 11 may be composed of two paths of photodiodes and a transimpedance amplifier circuit. Such as a transimpedance amplifier circuit designed based on a high-precision and high-speed budget amplifier OPA847 and adopting two-way PIN diodes.
Further, the zero-crossing comparison module 12 may employ a zero-crossing comparison circuit. Such as designing a zero-crossing comparison circuit based on the high-speed comparator LM 311.
Further, the controller 13 may employ an advanced reduced instruction set machine (ARM), a Field Programmable Gate Array (FPGA), or the like.
Further, the upper computer 14 may be a general personal computer.
Claims (6)
1. The utility model provides a rotor stator axial clearance on-line measuring system based on fexole common optical path structure which characterized by includes: the device comprises a sweep frequency light source, an optical fiber, a coupler, a circulator, an optical fiber probe, a photodiode, a signal conditioning module, a signal acquisition module, an optical fiber delayer, a balance receiving module, a zero-crossing detection module and a controller; the sweep frequency light source emits sweep frequency laser which is coupled into the input end of the coupler through the optical fiber; the first output end of the coupler is connected with the input end of the circulator through an optical fiber; the first output end of the circulator is connected with the optical fiber probe through an optical fiber; the surface of the optical fiber probe is processed, so that one part of the sweep frequency laser is emitted to the surface of a measured object and reflected, the other part of the sweep frequency laser is directly reflected on the surface of the optical fiber probe, the reflected light on the surface of the measured object is interfered with the reflected light on the surface of the optical fiber probe, returns to the first output end of the circulator through the optical fiber and is transmitted out from the second output end of the circulator, and an interference light signal is transmitted out from the second output end of the circulator and then is received by the photodiode through the optical fiber; the photodiode receives the interference light signal to generate an electric signal, and transmits the electric signal to the first signal conditioning module, and the first signal conditioning module conditions the electric signal and transmits the conditioned electric signal to the signal acquisition module; the second output end of the coupler enters the input end of the first coupler through the optical fiber; the first output end of the first coupler is connected with the optical fiber delayer through an optical fiber; the second output end of the first coupler is connected with the first input end of the second coupler through an optical fiber; the output end of the optical fiber delayer is connected with the second input end of the second coupler through an optical fiber; the two paths of optical signals interfere in the second coupler and are received by the balanced receiving module, and the optical signals received by the balanced receiving module are conditioned by the second signal conditioning module; the signal conditioned by the second signal conditioning module enters a zero-crossing comparator to generate sampling clock signals with equal k intervals; the sampling clock signals with equal k intervals generated by the zero-crossing comparator drive the signal acquisition module; the signal collected by the signal collection module is output through the controller control.
2. The system for on-line measurement of rotor-stator axial gap based on Fizeau common optical path structure as claimed in claim 1, wherein the controller controls the swept-frequency light source (1) and the second acquisition module.
3. The system according to claim 1, wherein the swept-frequency light source is a common constant-frequency interval swept-frequency light source or a constant-wavelength interval swept-frequency light source; the optical fiber is a mode optical fiber; the coupler adopts a common optical fiber splitter; the circulator can adopt a polarization-maintaining three-port optical circulator, an optical fiber circulator and an optical fiber three-port circulator; the circulator functions to transmit the interference optical signal to the photodiode but not to the coupler.
4. The system according to claim 1, wherein the optical fiber probe is a graded index lens or a fiber + quartz lens sensor structure, and is coated with a weak reflective film on the end surface of the optical fiber, the circulator, the optical fiber probe, and the optical fiber between the circulator and the optical fiber probe form a fizeau interference structure, and the reference optical signal reflected at the end surface of the optical fiber probe and the reflected optical signal reflected at the side surface propagate in the same optical fiber to cancel out temperature drift and phase jitter caused by temperature drift and vibration; the interference signal is transmitted to the photodiode when it reaches the circulator.
5. The system according to claim 1, wherein the photodiode can be an avalanche photodiode or a PIN diode; the first signal conditioning module can be composed of a transimpedance amplifying circuit and a filter circuit; the signal acquisition module can adopt an analog-digital conversion module; the coupler can adopt an optical fiber splitter, the optical fiber delayer selects a single-mode optical fiber or a multi-mode optical fiber with optical path difference, the equivalent optical path difference of the optical fiber extender is s, and the equivalent optical path difference of the axial distance is s0Then s is less than or equal to s0。
6. The system according to claim 1, wherein the balanced receiving module comprises two sets of photodiodes and a transimpedance amplifier.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110081829A (en) * | 2019-05-31 | 2019-08-02 | 天津大学 | Turn stator axial gap on-line measurement system based on what Feisuo was total to light channel structure |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110081829A (en) * | 2019-05-31 | 2019-08-02 | 天津大学 | Turn stator axial gap on-line measurement system based on what Feisuo was total to light channel structure |
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