CN203455033U - Optical fiber sensor for gas compressor fluid multi-parameter measurement - Google Patents
Optical fiber sensor for gas compressor fluid multi-parameter measurement Download PDFInfo
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- CN203455033U CN203455033U CN201320452013.3U CN201320452013U CN203455033U CN 203455033 U CN203455033 U CN 203455033U CN 201320452013 U CN201320452013 U CN 201320452013U CN 203455033 U CN203455033 U CN 203455033U
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- optical fiber
- elastic strain
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Abstract
The utility model provides an optical fiber sensor for gas compressor fluid multi-parameter measurement. Bragg grating type optical fibers are symmetrically distributed on the surface of an annular elastic strain sheet, and static pressure is calculated through the offset of an optical fiber central wavelength. Light intensity optical fibers vertically irradiate the center of the elastic strain sheet, two sets of receiving optical fibers receive reflected light, the offset distance of the elastic strain sheet is calculated through the light intensity ratio of the receiving optical fibers, and therefore total pressure is calculated. A temperature measurement grating optical fiber is pasted on the inner wall of a pitot tube, and the total temperature of a gas compressor is calculated through the offset of the central wavelength of the temperature measurement grating optical fiber. The other temperature measurement grating optical fiber is horizontally fixed to the inner side of a barrel-shaped metal outer shell to measure the temperature of a work environment, and temperature compensation is carried out on the total pressure and the static pressure. The optical fiber sensor has the advantages of being small in size, simple in structure and strong in capacity of resisting disturbance, and one sensor can measure the total pressure, the static pressure, the total temperature, the flow and multiple parameters of fluid.
Description
Technical field
The present invention relates to the fiber optic sensor technology field of engine gas flow measurement, be specially a kind of light intensity formula for pneumatic plant fluid measuring multiple parameters and raster pattern hybrid fiber sensor.
Background technology
Optical fiber sensing technology arises from the seventies in last century, and the nineties enters China.Current domestic You Duojia research institution starts to utilize technique to carry out research and development and the making of product.For the gas flow sensor that needs to use under the particular surroundingss such as Aeronautics and Astronautics, be characterized in the linearity of existing higher dynamic response and static measurement preferably, also to there be anti-electromagnetic interference (EMI) and better high-temperature stability.
Pneumatic plant is one of core component of aeromotor, the normal operation important role of its duty to whole engine.And that the pneumatic plant of high pressure ratio is the development trend of military aero-engine is required, be again the parts that easily break down in aeromotor, and generally, pressure ratio is higher, more easily there is surge.If pneumatic plant cisco unity malfunction to such an extent as to surge occurs, may cause the catastrophic failures such as leaf destruction, structural failure, firing chamber overtemperature and engine kill, it is necessary therefore it being carried out to monitoring in real time.And in the monitoring of numerous parameters, the measurement of flow is again Focal point and difficult point wherein.Optic flow sensor is than conventional pressure transducer, and it has higher sensitivity to strain, temperature, displacement etc., has again the advantages such as volume is little, lightweight, anticorrosive, anti-electromagnetic interference (EMI) simultaneously.Therefore using optical fibre sensor is measured pneumatic plant gas flow, for pneumatic plant gas flow is reliable, accurately measures a kind of settling mode is provided.In addition, in high-acruracy survey, solving issues of temperature compensation is also the key issue of optic flow sensor in practical.
The human hairs such as the Cheng Jia of Zhejiang Province Measure Science & Technology Research Institute understand a kind of Multi-section distributed fiber grating hot-type flow sensor (Chinese patent 102564504, on 07 11st, 2012), in this sensor tube wall, there are 3 fiber bragg grating sensors, be arranged symmetrically with into " river " font, and 3 optical fiber are positioned on same sagittal plane.This sensor is measured the temperature of fluid different piece by grating light, draw the flow of fluid.Therefore this flow sensor response speed is very slow; Measured gas composition changes place greatly, and because of cp value and thermal conductivity variation, measured value is more big changes and produces error; Due to mechanical fiber optic intensity difference, for flow velocity blower outlet faster, because pneumatic plant bore is larger, optical fiber may rupture.Therefore further a kind of response for blower outlet of research sensitive, measure accurate flow of light quantity sensor, can be used as a pith of pneumatic plant sensing system.
Summary of the invention
The technical matters solving
The problem existing for solving prior art, the present invention proposes a kind of light intensity formula for pneumatic plant fluid measuring multiple parameters and raster pattern hybrid fiber sensor.
Technical scheme
Light intensity formula and a raster pattern hybrid fiber sensor for pneumatic plant fluid measuring multiple parameters, comprise pitot tube 11; It is characterized in that: also comprise annular static pressure elastic strain sheet 1, circular stagnation pressure elastic strain sheet 2, tubular metal-packaged shell 3, two circle axis light strong reflection formula fibre-optical probe 4, thermometric grating fibers 8 and thermometric grating fibers 10; Tubular metal-packaged shell 3 is connected in the measurement interface of pitot tube 11, at tubular metal-packaged shell 3, be connected part with pitot tube 11 and center be set with the annular static pressure elastic strain sheet 1 of through hole, the other end at tubular metal-packaged shell 3 is provided with through hole, two circle axis light strong reflection formula fibre-optical probes 4 are placed in the vacuum chamber of tubular metal-packaged shell 3, and are drawn and transmitted and received optical fiber by through hole; Between annular static pressure elastic strain sheet 1 and two circle axis light strong reflection formula fibre-optical probe 4, be provided with circular stagnation pressure elastic strain sheet 2; Thermometric grating fibers 10 is arranged on the inwall of pitot tube 11 pitot hole B; Thermometric grating fibers 8 is arranged on the inwall of vacuum chamber of tubular metal-packaged shell 3; Described annular static pressure elastic strain sheet 1 is to paste some tonometric grating fibers on annular static pressure elastic strain sheet, and some tonometric grating fibers 9 distribute along even circumferential; On described two circle axis light strong reflection formula fibre-optical probe 4 transmit and receive optical fiber arrange for: the center of optical fiber is a launching fiber, launching fiber outer is arranged with the six roots of sensation and receives optical fiber and form first group of outer 12 root receiving fiber that are arranged with that receive that 6, the first groups of optical fiber receive optical fiber 6 and form second group and receive optical fiber 7; Described annular static pressure elastic strain sheet 1, circular stagnation pressure elastic strain sheet 2, thermometric grating fibers 8 and thermometric grating fibers 10 are provided with signal output connecting line.
Described measuring pressure grating fibers 9 is Bragg grating optical fiber.
Described two circle axis light strong reflection formula fibre-optical probe 4 is 0.25mm～2.5mm with the distance of circular stagnation pressure elastic strain sheet 2.
The outside of described tubular metal-packaged shell 3 applies high-temperaure coating.
Described annular static pressure elastic strain sheet 1 and circular stagnation pressure elastic strain sheet 2 are selected comprehensive silicon material.
Beneficial effect
The present invention adopts optical fiber as the critical component of measurement and the temperature compensation of engine flow, has proposed a kind of light intensity formula and raster pattern hybrid fiber flow sensor.This sensor construction is simple, volume is little, precision is high, adopt thermometric grating optical fiber measurement compressor delivery temperature, adopt measuring pressure grating fibers to measure static pressure, adopt the distance of light intensity reflection type optical fiber measurement elastic strain sheet to reach the object of total pressure measurement, thereby accurately measure the exact value of the flow of compressor air inlet machine mouth.Adopt raster pattern optical fiber measurement sensor temperature of living in further to improve sensor accuracy in order to carry out the compensation of temperature drift simultaneously.So this sensor of short summary has the following advantages: 1, the present invention adopts elastic strain sheet as sensitive element, application grating fibers and light intensity optical fiber are as measuring sensor, and this mode can effectively improve the precision of flow measurement; 2, the present invention adopts the direct survey sensor of grating fibers environment temperature of living in, utilizes temperature compensation to realize the accurate measurement to pressure; 3, sensor construction of the present invention is simple, volume is little, lightweight, antijamming capability is strong and precision reliability is high.
Accompanying drawing explanation
Fig. 1: structural representation of the present invention;
Fig. 2: gaging pressure grating fibers distribution plan in Fig. 1
Fig. 3: the partial enlarged drawing of two circle axis light strong reflection formula optical fiber in Fig. 1;
Wherein: 1, static pressure elastic strain sheet; 2, stagnation pressure elastic strain sheet; 3, tubular metal shell; 4, fibre-optical probe; 5, launching fiber; 6, receive optical fiber; 17, receive optical fiber 2; 8, thermometric grating fibers 1; 9 pressure measurement grating fibers; 10, thermometric grating fibers 2; 11, pitot tube; A, baroport; B, pitot hole
Embodiment
Below in conjunction with specific embodiment, the present invention is described:
With reference to accompanying drawing 1, a kind of light intensity formula for pneumatic plant fluid measuring multiple parameters and raster pattern hybrid fiber sensor in the present embodiment comprise pitot tube 11; It is characterized in that: also comprise annular static pressure elastic strain sheet 1, circular stagnation pressure elastic strain sheet 2, tubular metal-packaged shell 3, two circle axis light strong reflection formula fibre-optical probe 4, thermometric grating fibers 8 and thermometric grating fibers 10; Tubular metal-packaged shell 3 is connected in the measurement interface of pitot tube 11, at tubular metal-packaged shell 3, be connected part with pitot tube 11 and center be set with the annular static pressure elastic strain sheet 1 of through hole, the other end at tubular metal-packaged shell 3 is provided with through hole, two circle axis light strong reflection formula fibre-optical probes 4 are placed in the vacuum chamber of tubular metal-packaged shell 3, and are drawn and transmitted and received optical fiber by through hole; Between annular static pressure elastic strain sheet 1 and two circle axis light strong reflection formula fibre-optical probe 4, be provided with circular stagnation pressure elastic strain sheet 2; Thermometric grating fibers 10 is arranged on the inwall of pitot tube 11 pitot hole B; Thermometric grating fibers 8 is arranged on the inwall of vacuum chamber of tubular metal-packaged shell 3; Described annular static pressure elastic strain sheet 1 is to paste some tonometric grating fibers on annular static pressure elastic strain sheet, and 8 groups of tonometric grating fibers 9 distribute along even circumferential; On described two circle axis light strong reflection formula fibre-optical probe 4 transmit and receive optical fiber arrange for: the center of optical fiber is a launching fiber, launching fiber outer is arranged with the six roots of sensation and receives optical fiber and form first group of outer 12 root receiving fiber that are arranged with that receive that 6, the first groups of optical fiber receive optical fiber 6 and form second group and receive optical fiber 7; Described annular static pressure elastic strain sheet 1, circular stagnation pressure elastic strain sheet 2, thermometric grating fibers 8 and thermometric grating fibers 10 are provided with signal output connecting line.
Measuring pressure grating fibers is symmetrical and be uniformly distributed in annular static pressure foil gauge surface.
The axis direction of light intensity fibre-optical probe should overlap with the axis direction of elastic strain sheet.
The distance of light intensity fibre-optical probe and elastic strain sheet remains on 0.25mm-2.5mm.
The material of selected elastic strain sheet is special composite material, and that this material has is high temperature resistant, the feature of the higher-strength limit and the higher proportion limit.
Selected tubular metal-packaged shell, the metal that thermal conductivity is good is selected in inner side, and outside adopts the metal of poor thermal conductivity and adds high-temperaure coating.
Between the edge on the outward flange of described annular static pressure elastic strain sheet and described Metal Packaging housing top, by securing member, be connected.
The inward flange of described annular static pressure elastic strain sheet is closely connected with the stagnation pressure tube of described pitot tube, and scribbles high-intensity sealing glue.
The edge of described stagnation pressure elastic strain sheet is connected by securing member with the inner draw-in groove of described Metal Packaging, and scribbles high-intensity sealing glue, and described stagnation pressure elastic strain sheet and the internal cavities of housing form an airtight vacuum chamber.
The material of static pressure elastic strain sheet 1 and stagnation pressure elastic strain sheet 2 is special composite material, that this material has is high temperature resistant, the feature of the higher-strength limit and the higher proportion limit, in the present invention, can select comprehensive silicon material, this is to be 0-5Mpa because the temperature of aero-engine compressor can reach 500K left and right and need the pressure of measuring.
Tubular metal shell 3 is comprised of materials at two layers, and for guaranteeing the strength and stiffness requirement of encapsulating housing, materials at two layers is alloy material.Wherein internal layer is the alloy material that thermal conductivity is good, and to guarantee the thermometric grating fibers operating ambient temperature of survey sensor accurately, the metal of outer employing poor thermal conductivity also adds high-temperaure coating.
Pressure measurement grating fibers 9 sticks on static pressure foil gauge surface by particular adhesive, because the temperature of aero-engine compressor can reach 500k, so this bonding agent will have high-temperature stability.
The incident light source of the light intensity reflection type optical fiber in the present embodiment should be selected according to photoelectric commutator, selects ruddiness as light source in the present invention.And incident light is shining into sealed vacuum chamber and can gets rid of external light source and disturb the impact on sensor.
When light intensity formula of the present invention and the work of raster pattern hybrid fiber flow sensor, when extraneous static pressure acts on static pressure elastic strain sheet 1, there is deformation in static pressure elastic strain sheet 1, paste with pressure measurement grating fibers 9 length on 1 surface and change simultaneously, and then cause that the centre wavelength of optical grating reflection is offset; Stagnation pressure acts on stagnation pressure elastic strain sheet 2 simultaneously, there is deformation in stagnation pressure foil gauge 2, distance generation subtle change between incident optical 5 and stagnation pressure elastic strain sheet 2 lower surface centers, thus the light intensity that makes inner ring receive optical fiber 6 and 7 receptions of outer ring reception optical fiber changes; Meanwhile, the thermometric grating fibers 8 in same temperature field can detect the variation of temperature generation and cause that the centre wavelength of optical grating reflection is offset.Therefore can be according to 9 optical grating reflection centre wavelength and the relation between static pressure elastic strain sheet, and in conjunction with the relation of pressure and the strain of elastic strain sheet, calculate the size of measured static pressure; According to the relation between light intensity variation and variable in distance, and in conjunction with the relation between pressure and the strain of elastic strain sheet, calculate the size of total pressure pressure of surveying; The side-play amount of the optical grating reflection centre wavelength by thermometric grating 8 calculates the size of temperature of living in, thereby realizes accurate measurement and the temperature compensation of pneumatic plant static pressure and stagnation pressure; The side-play amount of the optical grating reflection centre wavelength by thermometric grating 10 calculates pneumatic plant stagnation temperature.According to the relation of static pressure, stagnation pressure, stagnation temperature and gas flow, can calculate the size of surveyed gas flow.Concrete computation process is as follows:
Stagnation pressure elastic strain sheet be subject to stress-strain formula as follows:
z=p*/（AE） （1）
The dependent variable of z for producing in formula, the cross-sectional area that A is pressure-acting, the elastic modulus that E is selected materials, p* is applied pressure.
With reference to accompanying drawing 3, according to the fibre bundle arrangement mode of two circle coaxial optical fiber probes, the light intensity that two groups of reception optical fiber are received is carried out ratio processing, can obtain the computing formula of the output characteristics modulating function of this sensor,
In formula:
M (z)---be two groups of ratios that receive fibre bundle light intensity;
I
r1---represent that first group receives light intensity/cd that fibre bundle receives;
I
r2---represent that second group receives light intensity/cd that fibre bundle receives.
By two groups of ratio M (z) that receive the light intensity of collecting fiber, can calculate the variation z that strain displacement occurs, specific formula for calculation is as follows:
Through type (3) is known, when optical fiber structure parameter incident optical with receive the distance between axles d of optical fiber, the radius a of fibre bundle optical fiber
0, optical fiber maximum incident angle θ
0one regularly, and optical fiber output characteristics is only relevant to the distance z between strain diaphragm with fiber end face, and with the reflectivity of the intensity of light source, reflecting body, the intrinsic loss of optical fiber and the factors such as added losses brought by bending are irrelevant.Therefore light intensity is carried out obtaining its ratio after opto-electronic conversion, through type (3) convolution (1) calculates the stagnation pressure of pneumatic plant.
The relation of static pressure elastic strain sheet dependent variable and static pressure:
During normal operation of sensor, there is pressure differential deltap p in cyclic spring foil gauge both sides:
Δp＝p-p* （4）
In formula, p is static pressure, and p* is stagnation pressure.
Prove by experiment, the dependent variable ε of cyclic spring foil gauge and Δ p are proportional:
ε∝Δp （5）
The relation of grating wavelength side-play amount and strain:
Δλ
B＝(1-P
e)ε·λ
B （6）
P in formula
eit is the strain optical coefficient of optical fiber.
Therefore, Δ p and Δ λ
blinear, by the demodulation to light signal, can draw Δ λ
b, and then can draw Δ p.By formula (1), formula (3), obtain stagnation pressure p*, thereby can draw the static pressure p of fluid.
Can obtain by temperature-measuring optical fiber 10 the stagnation temperature T* of pneumatic plant.The variation of the operating ambient temperature that can record by raster pattern optical fiber 8, compensation is because the measurement of the elastic strain sheet that temperature variation causes is drifted about.The relation that temperature variation changes in grating wavelength:
Δλ＝(α+ξ)λΔT （7）
In formula, the thermal expansivity that α is optical fiber, the thermo-optical coeffecient that ξ is optical fiber, the variation that Δ λ is wavelength, the variation that Δ T is temperature.
According to the relation of static pressure, stagnation pressure, stagnation temperature and gas flow, can calculate the size of surveyed gas flow:
In formula, K is constant, and κ is gas law constant, and A is for measuring the pneumatic area in cross section, and p* is stagnation pressure, and p is static pressure, and T* is stagnation temperature.
By the output terminal of grating fibers is connected on Wavelength demodulation instrument, can record the variation of wavelength, thereby by calculating the variable quantity of temperature, complete the design of the hybrid fiber flow sensor of whole light intensity formula optical fiber and raster pattern optical fiber.
Claims (5)
1. for a Fibre Optical Sensor for pneumatic plant fluid measuring multiple parameters, comprise pitot tube (11); It is characterized in that: also comprise annular static pressure elastic strain sheet (1), circular stagnation pressure elastic strain sheet (2), tubular metal-packaged shell (3), two circle axis light strong reflection formula fibre-optical probes (4), thermometric grating fibers 1(8) and thermometric grating fibers 2(10); Tubular metal-packaged shell (3) is connected in the measurement interface of pitot tube (11), at tubular metal-packaged shell (3), be connected part with pitot tube (11) and center be set with the annular static pressure elastic strain sheet (1) of through hole, the other end at tubular metal-packaged shell (3) is provided with through hole, two circle axis light strong reflection formula fibre-optical probes (4) are placed in the vacuum chamber of tubular metal-packaged shell (3), and are drawn and transmitted and received optical fiber by through hole; Between annular static pressure elastic strain sheet (1) and two circle axis light strong reflection formula fibre-optical probes (4), be provided with circular stagnation pressure elastic strain sheet (2); Thermometric grating fibers 2(10) be arranged on the inwall of pitot tube (11) pitot hole B; Thermometric grating fibers 1(8) be arranged on the inwall of vacuum chamber of tubular metal-packaged shell (3); Described annular static pressure elastic strain sheet (1) is to paste some tonometric grating fibers on annular static pressure elastic strain sheet, and some tonometric grating fibers (9) distribute along even circumferential; On described two circle axis light strong reflection formula fibre-optical probes (4) transmit and receive optical fiber arrange for: the center of optical fiber is a launching fiber, the outer six roots of sensation reception optical fiber that is arranged with of launching fiber forms first group of reception optical fiber (6), and first group of outer 12 root receiving fiber that are arranged with that receive optical fiber (6) forms second group of reception optical fiber (7); Described annular static pressure elastic strain sheet (1), circular stagnation pressure elastic strain sheet (2), thermometric grating fibers 1(8) and thermometric grating fibers 2(10) signal output connecting line be provided with.
2. the Fibre Optical Sensor for pneumatic plant fluid measuring multiple parameters according to claim 1, is characterized in that: described tonometric grating fibers (9) is Bragg grating optical fiber.
3. the Fibre Optical Sensor for pneumatic plant fluid measuring multiple parameters according to claim 1, is characterized in that: described two circle axis light strong reflection formula fibre-optical probes (4) are 0.25mm～2.5mm with the distance of circular stagnation pressure elastic strain sheet (2).
4. the Fibre Optical Sensor for pneumatic plant fluid measuring multiple parameters according to claim 1, is characterized in that: the outside of described tubular metal-packaged shell (3) applies high-temperaure coating.
5. the Fibre Optical Sensor for pneumatic plant fluid measuring multiple parameters according to claim 1, is characterized in that: described annular static pressure elastic strain sheet (1) and circular stagnation pressure elastic strain sheet (2) are selected comprehensive silicon material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320452013.3U CN203455033U (en) | 2013-07-26 | 2013-07-26 | Optical fiber sensor for gas compressor fluid multi-parameter measurement |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320452013.3U CN203455033U (en) | 2013-07-26 | 2013-07-26 | Optical fiber sensor for gas compressor fluid multi-parameter measurement |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103411643A (en) * | 2013-07-26 | 2013-11-27 | 西北工业大学 | Optical fiber sensor and method for measuring multiple parameters of air compressor fluid |
| CN110530277A (en) * | 2019-07-30 | 2019-12-03 | 西安交通大学 | A kind of anti-dust optical fiber sensing probe of wide range for measuring blower air gap |
-
2013
- 2013-07-26 CN CN201320452013.3U patent/CN203455033U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103411643A (en) * | 2013-07-26 | 2013-11-27 | 西北工业大学 | Optical fiber sensor and method for measuring multiple parameters of air compressor fluid |
| CN103411643B (en) * | 2013-07-26 | 2016-09-07 | 西北工业大学 | Fibre Optical Sensor and measuring method for air compressor fluid measuring multiple parameters |
| CN110530277A (en) * | 2019-07-30 | 2019-12-03 | 西安交通大学 | A kind of anti-dust optical fiber sensing probe of wide range for measuring blower air gap |
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Granted publication date: 20140226 Effective date of abandoning: 20160907 |
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| C25 | Abandonment of patent right or utility model to avoid double patenting |