Optical fiber vector wind speed measuring system based on gallium arsenide crystal and measuring method thereof

Abstract

The invention provides an optical fiber vector wind speed measurement system based on gallium arsenide crystals. The system comprises a detection light source, a heating light source, an optical fiber coupler, a detection instrument, a data acquisition module, a sensing device and a controller. The detection light source, the heating light source, the sensing device and the detection instrument are sequentially connected with ports of the optical fiber coupler, and the detection instrument, the data acquisition module and a port of the controller are sequentially connected; the sensing device comprises a transmission optical fiber, a plurality of optical fiber sensing parts composed of gallium arsenide crystals and the transmission optical fiber, and a porous pipeline. The system is simple in structure, high in stability, long in service life and easy to miniaturize and integrate. The invention further provides a measuring method based on the system, more accurate wind speed vector information is obtained through an average wavelength shift difference wavelength modulation method and an optical fiber sensing array structure angle analysis method by utilizing the characteristic that the gallium arsenide crystal absorption spectrum changes along with the temperature, errors are small, the requirements of various application scenes can be met, and the measuring method is suitable for large-scale popularization and application. Good social and economic values are realized.

Description

Technical Field

[0001] The present invention relates to the field of sensing technology, and in particular to an optical fiber vector wind speed measurement system based on gallium arsenide crystal and a measurement method thereof. Background Art

[0002] Wind speed measurement technology has important social and economic significance in modern industrial and agricultural production, scientific research, environmental and meteorological monitoring, etc. However, traditional anemometers and wind speed measurement technology can no longer meet the needs of modern high-tech development. For example, mechanical anemometers cannot measure weak wind speeds due to the existence of friction; differential pressure anemometers do not measure low wind speeds well; ultrasonic anemometers are large and have high requirements; although traditional electrical thermal anemometers can measure low wind speeds, they are easily affected by adverse factors such as electromagnetic interference, high voltage, and high radiation.

[0003] The anemometer based on fiber optic sensing technology not only combines the low wind speed measurement of thermal anemometer, but also has the advantages of small size, light weight, and strong anti-electromagnetic interference ability. There are two main types of fiber optic anemometers: one is to measure wind speed by bending or twisting the fiber optic structure, mainly using fiber grating or fiber interference structure to detect the stress generated by wind to measure wind speed, but it has the disadvantages of large size and easy damage of fiber optic structure; the other is the fiber optic hot wire anemometer, which uses the temperature change caused by the heat loss of the fiber optic sensing structure to obtain the drift information of the spectrum through the spectrometer to demodulate the wind speed value. However, the existing fiber optic anemometer is not conducive to miniaturization and integration due to its cumbersome system structure, and can generally only complete the measurement of wind speed, and fails to further obtain accurate directional vector information.

[0004] Therefore, developing a fiber optic hot wire measurement system that can obtain more accurate wind intensity and wind direction information and is simpler and more efficient has become a key issue that needs to be urgently addressed in the current field of wind speed measurement technology. Summary of the invention

[0005] The purpose of the present invention is to provide a fiber optic vector wind speed measurement system based on gallium arsenide crystal and a measurement method thereof in view of the defects existing in the prior art, and to utilize the characteristic that the absorption edge spectrum of gallium arsenide semiconductor material changes with temperature, and to reduce the influence of wind direction through the wavelength demodulation method of average wavelength shift difference, so as to further improve the accuracy of measurement information; at the same time, the accurate vector wind speed information is obtained by combining the fiber optic sensor array structure angle analysis method. Another aspect of the present invention provides a measurement method of a fiber optic vector wind speed measurement system based on gallium arsenide crystal, which has a simple structural design, high accuracy and sensitivity, more accurate measurement, and is easy to be miniaturized and integrated, and is suitable for various application scenarios, and has extremely high social and economic value in the fields of modern industrial applications, scientific research, environmental and meteorological monitoring, etc.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A fiber optic vector wind speed measurement system based on gallium arsenide crystal comprises a detection light source, a heating light source, a fiber optic coupler, a detection instrument, a sensor device and a controller; the detection light source, the heating light source, the sensor device and the detection instrument, the data acquisition module and the ports of the fiber optic coupler are connected in sequence, and the detection instrument and the data acquisition module are connected in sequence to the controller port; the sensor device comprises a transmission optical fiber, a plurality of optical fiber sensing components composed of gallium arsenide crystal and the transmission optical fiber, and a porous pipe; the plurality of optical fiber sensing components are arranged in the holes of the pipe; the plurality of optical fiber sensing components are distributed in an array structure.

[0008] Furthermore, one of the multiple optical fiber sensor components is arranged in the middle of the porous pipe, and the other optical fiber sensor components are arranged in a symmetrical distribution; the optical fiber sensor component arranged in the middle of the porous pipe serves as a central heat source.

[0009] Furthermore, the optical fiber sensing component includes an optical fiber sensing probe composed of a gallium arsenide crystal and a transmission optical fiber.

[0010] Furthermore, the optical fiber sensing probe includes a transmission optical fiber, a light source, and a gallium arsenide crystal coated with a dielectric transmission film and a dielectric high reflection film.

[0011] Another aspect of the present invention further provides a measurement method based on the optical fiber vector wind speed measurement system, the method comprising:

[0012] Step S1, using the characteristic that the absorption spectrum of the transition zone of the gallium arsenide crystal changes with temperature, collecting, adjusting and analyzing signal information, and using a mediation method to obtain the corresponding relationship information between the absorption spectrum wavelength and temperature;

[0013] Step S2, collecting, analyzing and processing signal information, and using the wavelength demodulation method of average wavelength shift difference to obtain accurate wind intensity information;

[0014] Step S3: Obtain accurate wind speed vector information through optical fiber sensor array structure angle analysis.

[0015] Furthermore, in step S1, the adverse effects of light intensity are eliminated, including analyzing and eliminating the influence of background noise of detection instruments and sensors, and obtaining the corresponding relationship between the absorption spectrum characteristic wavelength and temperature by collecting, analyzing and processing the absorption spectrum characteristic wavelength, temperature and light intensity data signal information of the gallium arsenide crystal.

[0016] Furthermore, in step S2, by collecting, analyzing and processing the optical fiber sensor signal information, the characteristic wavelength of the absorption spectrum of the gallium arsenide crystal is used, and the temperature changes and drifts due to the different heat taken away by the optical fiber sensor probe. The wavelength demodulation method of the average wavelength shift difference is used to demodulate and calculate the wind speed based on the absorption spectrum characteristic wavelength drift principle; the specific measurement method satisfies the following formula:

[0017]

[0018] In formula (1),

[0019]

[0020] In the formula, It is the transient temperature rise of the circular heat source medium on the same plane at any position in the moving medium; is the transient temperature rise of the central heat source; The wavelength drift caused by the temperature change caused by wind speed; is the gas volume vector; P is the heating power of the heat source; K is the temperature sensitivity of the gallium arsenide crystal; i is a positive integer.

[0021] Furthermore, the i is a positive integer from 1 to 6.

[0022] Furthermore, in step S3, wind direction information of the wind field is obtained by an optical fiber sensing structure angle analysis method; and wind speed direction information is obtained by analyzing the absorption spectrum drift information of the gallium arsenide crystal obtained by the optical fiber sensor probes at different positions.

[0023] Furthermore, the wind direction information is within the range of (θ, θ+60°), wherein θ is the angular position of the optical fiber sensor probe where the absorption spectrum drift is the largest.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The optical fiber vector wind speed measurement system provided by the present invention has a simple structure, small size, strong stability, and long service life. While being able to achieve wide range, high sensitivity, and fast response time measurement, it also has the advantage of being easy to miniaturize and integrate, and can achieve point, pipeline, and insertion measurements, and can be suitable for various application scenarios.

[0026] (2) The measurement method based on the above-mentioned vector wind speed measurement system provided by the present invention utilizes the characteristic that the absorption edge spectrum of gallium arsenide semiconductor material changes with temperature to obtain information on the temperature change of the sensor, establishes the relationship between the absorption edge wavelength drift of gallium arsenide semiconductor material and wind speed, and realizes accurate measurement of wind intensity.

[0027] (3) The present invention combines the wavelength adjustment method of average wavelength shift difference and the optical fiber sensor array structure angle analysis method to obtain more accurate wind speed vector information with small error, which can meet the technical requirements of various application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the optical fiber vector wind speed measurement system based on the thermo-optical effect of the present invention;

[0029] Figure 2 Schematic diagram of the structure of the optical fiber sensing component of this embodiment;

[0030] Figure 3 It is a schematic diagram of the structure of the optical fiber sensor probe;

[0031] Figure 4 Schematic diagram of the flow of the measurement method according to an embodiment of the present invention;

[0032] Figure 5 This is a principle diagram of wavelength drift in the transition region of a gallium arsenide crystal at different temperatures according to an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structural angle analysis of the optical fiber sensor array according to an embodiment of the present invention.

[0034] In the figure:

[0035] 21-transmission optical fiber; 22-gallium arsenide crystal; 23-porous pipe;

[0036] 31- detection light; 32- heating light;

[0037] 61, 62, 63-fiber optic sensor probes; 64, 65, 66-wind direction. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar figure numbers always represent the same or similar parts or parts with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without paying creative work, all of which belong to the concept of the present invention.

[0039] like Figure 1As shown, the present invention provides a fiber optic vector wind speed measurement system based on gallium arsenide crystal, the system includes a detection light source, a heating light source, a fiber optic coupler, a sensor device, a detection instrument, a data acquisition module and a controller. The detection light source, the heating light source, the sensor device and the detection instrument are connected to the ports of the fiber optic coupler in sequence, and the detection instrument, the data acquisition module and the controller port are connected in sequence. The system has a simple design, high accuracy and sensitivity, more accurate measurement, and is easy to be miniaturized and integrated, and is suitable for various application scenarios.

[0040] like Figure 2 As shown, in this system, the sensing device includes a transmission optical fiber 21, an optical fiber sensing component composed of a gallium arsenide crystal 22 and the transmission optical fiber, and a porous pipe 23. According to the actual measurement needs, multiple optical fiber sensor probes can be arranged in the porous pipe, which can further increase the number of optical fiber sensor probes; the optical fiber sensor probes are distributed in an array structure in the porous pipe, and the optical fiber sensing components distributed in the array structure are conducive to the analysis of wind speed vector information; the optical fiber sensing component arranged at the center of the porous pipe serves as a central heat source, so that the optical fiber sensing arrays uniformly arranged around it have the same temperature, and other optical fiber sensing components are symmetrically distributed and arranged in the porous pipe.

[0041] In this embodiment, according to actual measurement needs, the average wavelength shift can be used to further increase the number of optical fiber sensor probes on the basis of reducing the error influence of direction on wind speed measurement results, thereby further reducing the error caused by wind direction.

[0042] The optical fiber sensing component comprises an optical fiber sensing probe composed of a gallium arsenide crystal and a transmission optical fiber.

[0043] Specifically, Figure 3 As shown, the optical fiber sensing probe includes a transmission optical fiber 21, a light source, and a gallium arsenide crystal 22 coated with a dielectric transmission film and a dielectric high reflection film.

[0044] The light source includes a detection light 31 and a heating light 32 .

[0045] Preferably, the operating wavelength of the detection light source is 850-950 nm, and the operating wavelength of the heating light source is 750-850 nm.

[0046] In this embodiment, a measurement method based on the above system is also provided. The method is implemented based on the characteristics of semiconductor materials: when light passes through semiconductor materials, the material absorbs photon energy. When the photon energy exceeds the semiconductor bandgap width E g(T), the wavelength of the transmitted light will change. As a semiconductor material, the absorption edge spectrum change of gallium arsenide crystal is related to the temperature T; when the temperature changes, the wavelength of its absorption edge (transition zone) will drift. Therefore, the relevant temperature information can be obtained through the relationship between the characteristic wavelength of the gallium arsenide crystal absorption spectrum and temperature. The present invention uses the absorption spectrum wavelength demodulation method to use the drift information of the characteristic wavelength of the absorption spectrum to mediate and calculate the wind intensity information; by combining the optical fiber sensor probe array structure angle analysis method, the absorption spectrum drift information obtained by the optical fiber sensor probes at different positions is analyzed to obtain the wind direction information.

[0047] In this embodiment, the principle of the measurement method is as follows: the light emitted by the detection light source enters the fiber optic sensor probe based on gallium arsenide crystal through the fiber optic coupler, and the reflected light after passing through the gallium arsenide crystal is transmitted to the detection instrument through the fiber optic coupler. The detection instrument converts the received light into a digital signal, and the corresponding spectral drift information can be obtained by collecting, adjusting, analyzing and processing the digital signal; then, the wavelength adjustment method of the average wavelength shift difference and the angle analysis method of the fiber optic sensor probe array structure are combined to realize accurate analysis and measurement of wind intensity and wind direction information.

[0048] In this embodiment, the wind speed and wind direction information obtained is more accurate and has a smaller error through the wavelength demodulation method of average wavelength shift difference and the optical fiber sensor array structure angle analysis.

[0049] like Figure 4 As shown, the measurement method specifically includes:

[0050] Step S1, using the characteristic that the absorption spectrum of gallium arsenide semiconductor material changes with temperature, collecting, adjusting and analyzing data signal information, and obtaining relevant temperature information using a mediation method;

[0051] Step S2, collecting, analyzing and processing temperature signal information, and using the wavelength demodulation method of average wavelength shift difference to obtain accurate wind intensity information;

[0052] Step S3: Obtain accurate wind speed vector information through optical fiber sensor array structure angle analysis.

[0053] Wherein, in step S1, the absorption spectrum information of the gallium arsenide crystal is collected, adjusted and processed to obtain the corresponding relationship between the absorption spectrum wavelength and temperature.

[0054] In this step, since light intensity is affected by many factors, we first analyze and eliminate the adverse factors affecting light intensity, focusing on eliminating the noise of the detection instrument and the background noise of sensors, and then analyze and process the information including the characteristic wavelength of the absorption spectrum, light intensity and temperature, and obtain the corresponding relationship between the characteristic wavelength of the gallium arsenide crystal absorption spectrum and temperature.

[0055] In step S2, after eliminating the influence of adverse factors such as light intensity, the optical fiber sensing temperature data signal information is collected, analyzed and processed, and the characteristic wavelength of the absorption spectrum drifts due to the change in temperature caused by the different heat taken away by the optical fiber sensor probe, so as to obtain the corresponding relationship between the characteristic wavelength and the temperature.

[0056] Attached Figure 5 This is the principle of characteristic wavelength drift of the absorption spectrum of the absorption edge (transition zone) of the gallium arsenide crystal at different temperatures in the embodiment of the present invention. Its absorption characteristic wavelength drifts with the change of temperature.

[0057] like Figure 5 As shown in the figure, at different wind speeds, the amount of heat taken away from the fiber optic sensor probe is different, resulting in temperature changes, and the temperature change causes the wavelength of the absorption edge spectrum of the gallium arsenide crystal to shift; and the stronger the wind speed, the more heat is taken away, and the greater the drift of its characteristic wavelength. The drift information of its characteristic wavelength is used, and the wind intensity is calculated by averaging the wavelength shift; this method can reduce the error caused by wind direction, thereby obtaining a more accurate wind speed intensity. This measurement method satisfies the following formula:

[0058]

[0059] In formula (1),

[0060]

[0061] In the formula, It is the transient temperature rise of the circular heat source medium on the same plane at any position in the moving medium; is the transient temperature rise of the central heat source; The wavelength drift caused by the temperature change caused by wind speed; is the gas volume vector; P is the heating power of the heat source; K is the temperature sensitivity of the gallium arsenide crystal; i is a positive integer; further preferably, i is a positive integer of 1-6.

[0062] In this embodiment, the error influence on the wind speed measurement result can be reduced by averaging the wavelength shift difference, and the number of optical fiber sensor probes can be further increased to further reduce the error caused by wind direction.

[0063] In step S3, wind field vector information is obtained by using the optical fiber sensing structure angle analysis method. The specific analysis method is as follows:

[0064] Seven fiber optic sensor probes are distributed in the porous pipe, one of which is set in the middle of the pipe as the central heat source, so that the fiber optic sensor arrays evenly arranged around it have the same temperature. When the wind speed is in different directions, different fiber optic sensor probes take away different amounts of heat, and the temperature changes are also different, which will cause different drifts in the absorption spectrum of the gallium arsenide crystal.

[0065] like Figure 6 As shown, Figure 6 Three different wind directions are shown:

[0066] When the wind speed direction is wind direction 63, the heat taken away by the optical fiber sensor probe 61 is the largest, the temperature drops the most, and the drift of the absorption spectrum of the gallium arsenide crystal is also the largest, while the heat taken away by the optical fiber sensor probe 62 symmetrically distributed with the optical fiber sensor probe 61 is the smallest, the temperature drops the least, and the drift of the absorption spectrum of the gallium arsenide crystal is also the smallest. Therefore, according to the position information of the optical fiber sensor probe 61 and the optical fiber sensor probe 62, the heat information taken away by them, and the drift information of the absorption spectrum of the gallium arsenide crystal, the wind direction information of the wind speed can be analyzed and measured.

[0067] When the wind speed direction is wind direction 64, the heat taken away by the optical fiber sensor probe 61 and the optical fiber sensor probe 63 is the largest, but the optical fiber sensor probe 61 loses more heat than the optical fiber sensor probe 63, and the drift of the absorption spectrum of the gallium arsenide crystal is also larger. Therefore, according to the position information of the optical fiber sensor probe 61 and the optical fiber sensor probe 63, the difference in the heat taken away by them, and the difference in the absorption spectrum drift, the wind direction information of the wind speed can be analyzed and measured.

[0068] When the wind speed direction is wind direction 65, the heat removed by the optical fiber sensor probe 61 is the same as that by the optical fiber sensor probe 63, and the drift of the absorption spectrum of the gallium arsenide crystal is also the same. According to the position information of the optical fiber sensor probe 61 and the optical fiber sensor probe 63, the heat removed by them, and the drift information of the absorption spectrum, the wind direction information of the wind speed can be analyzed and measured.

[0069] The measurement method provided in this embodiment obtains the drift information of the GaAs absorption spectrum by analyzing the temperature information of different positions of the optical fiber sensor probe, and measures the wind direction information of the wind field. The wind direction information can be determined within the range of (θ, θ+60°), where θ is the angular position of the optical fiber sensor probe where the absorption spectrum drift is the largest. The wind direction information obtained by this method is more accurate and has a smaller error.

[0070] The above-mentioned embodiment is only the wind speed vector information measured by the position of the optical fiber sensing component set in the preferred specific mode of the present invention. The present invention can also obtain wind speed vector information by measuring the optical fiber sensing components at different positions, or further increase the number of optical fiber sensing components according to actual measurement needs to further obtain more accurate wind speed vector information.

[0071] The above embodiments are described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, which are merely illustrative rather than limiting. Any modification, variation or equivalent substitution made by a person skilled in the art under the guidance of the present invention without departing from the concept of the present invention shall fall within the scope of protection of the claims of the present invention.

Claims

1. An optical fiber vector wind speed measurement system based on gallium arsenide crystal, characterized in that: It comprises a detection light source, a heating light source, a fiber coupler, a detection instrument, a sensor device and a controller; the detection light source, the heating light source, the sensor device and the detection instrument, the data acquisition module and the ports of the fiber coupler are connected in sequence, and the detection instrument and the data acquisition module are connected in sequence to the controller port; the sensor device comprises a transmission optical fiber, a plurality of optical fiber sensing components composed of gallium arsenide crystals and transmission optical fibers, and a porous pipe; the plurality of optical fiber sensing components are arranged in the holes of the pipe; the plurality of optical fiber sensing components are distributed in an array structure.

2. The optical fiber vector wind speed measurement system according to claim 1, characterized in that: One of the multiple optical fiber sensor components is arranged in the middle of the porous pipe, and the other optical fiber sensor components are arranged in a symmetrical distribution; the optical fiber sensor component arranged in the middle of the porous pipe serves as a central heat source.

3. The optical fiber vector wind speed measurement system according to claim 2, characterized in that: The optical fiber sensing component comprises an optical fiber sensing probe composed of a gallium arsenide crystal and a transmission optical fiber.

4. The optical fiber vector wind speed measurement system according to claim 3, characterized in that: The optical fiber sensing probe comprises a transmission optical fiber, a light source and a gallium arsenide crystal coated with a dielectric transmission film and a dielectric high reflection film.

5. A measurement method based on the optical fiber vector wind speed measurement system according to any one of claims 1 to 4, characterized in that: The method comprises: Step S1, using the characteristic that the absorption spectrum of the transition zone of the gallium arsenide crystal changes with temperature, collecting, adjusting and analyzing signal information, and using a mediation method to obtain the corresponding relationship information between the absorption spectrum wavelength and temperature; Step S2, collecting, analyzing and processing signal information, and using the wavelength demodulation method of average wavelength shift difference to obtain accurate wind intensity information; Step S3: Obtain accurate wind speed vector information through optical fiber sensor array structure angle analysis.

6. The measuring method according to claim 5, characterized in that: In step S1, the adverse effects of light intensity are eliminated, including analyzing and eliminating the effects of background noise from detection instruments and sensors, and obtaining the corresponding relationship between the absorption spectrum characteristic wavelength and temperature by collecting, analyzing and processing the absorption spectrum characteristic wavelength, temperature and light intensity data signal information of the gallium arsenide crystal.

7. The measuring method according to claim 5, characterized in that: In step S2, by collecting, analyzing and processing the optical fiber sensor signal information, the characteristic wavelength of the absorption spectrum of the gallium arsenide crystal is used, and the characteristic wavelength drifts due to the temperature change caused by the different heat taken away by the optical fiber sensor probe. The wavelength demodulation method of the average wavelength shift difference is used to demodulate and calculate the wind speed based on the absorption spectrum characteristic wavelength drift principle; the specific measurement method satisfies the following formula: In formula (1), In the formula, It is the transient temperature rise of the circular heat source medium on the same plane at any position in the moving medium; is the transient temperature rise of the central heat source; The wavelength drift caused by the temperature change caused by wind speed; is the gas volume vector; P is the heating power of the heat source; K is the temperature sensitivity of the gallium arsenide crystal; i is a positive integer.

8. The measuring method according to claim 7, characterized in that: The i is a positive integer from 1 to 6.

9. The measuring method according to claim 5, characterized in that: In step S3, wind direction information of the wind field is obtained by an optical fiber sensing structure angle analysis method; and wind speed direction information is obtained by analyzing the absorption spectrum drift information of gallium arsenide crystals obtained by optical fiber sensor probes at different positions.

10. The measuring method according to claim 9, characterized in that: The wind direction information is within the range of (θ, θ+60°), where θ is the angular position of the optical fiber sensor probe where the absorption spectrum drift is the largest.

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