CN115717946A - Optical fiber sensor and measuring system for measuring temperature field of flow section of liquid metal - Google Patents
Optical fiber sensor and measuring system for measuring temperature field of flow section of liquid metal Download PDFInfo
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- CN115717946A CN115717946A CN202211433909.7A CN202211433909A CN115717946A CN 115717946 A CN115717946 A CN 115717946A CN 202211433909 A CN202211433909 A CN 202211433909A CN 115717946 A CN115717946 A CN 115717946A
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Abstract
The invention provides an optical fiber sensor and a measuring system for measuring a temperature field of a flowing section of liquid metal, wherein the measuring system comprises an array optical fiber sensor, a laser emitter, an optical fiber grating analyzer, a data acquisition computer and a liquid metal container, a flow channel is arranged in the liquid metal container, and the array optical fiber sensor is positioned in the flow channel; the array type optical fiber sensor comprises a buncher, an integrated board and N optical fiber temperature probes which are arranged on the integrated board in parallel, wherein N is more than 2, and the integrated board is arranged perpendicular to a flow channel; the laser emitter is arranged opposite to the buncher and can emit an excitation laser signal; the fiber bragg grating analyzer is in communication connection with the array type fiber optic sensor; and the data acquisition computer is in communication connection with the fiber grating analyzer. According to the invention, the measurement of the internal temperature of the liquid metal with high temperature, high pressure and corrosiveness is realized through the optical fiber temperature probe, and the temperature measurement requirements in the fields of nuclear reactors and the like and the temperature measurement requirements of related scientific research personnel during experimental research are favorably met.
Description
Technical Field
The invention relates to the technical field of multiphase flow parameter measurement and the field of nuclear reactor thermal hydraulic power, in particular to an optical fiber sensor and a measurement system for measuring a liquid metal flow cross-section temperature field, and particularly relates to an array type optical fiber temperature probe and a measurement system for measuring the liquid metal flow cross-section temperature field.
Background
The lead-based fast reactor has good neutron economy, strong heat transfer capability, good safety and the like, and is one of the main reactor types of the fourth generation nuclear reactor. However, the temperature measurement in the flowing process is very difficult due to the high temperature, the huge pressure difference, the complex thermal hydraulic phenomenon between loops and the corrosion characteristics of the lead-bismuth alloy, and certain hidden troubles are brought to the safe operation of the nuclear reactor. Therefore, accurate measurement of temperature field distribution information of the liquid metal in the flowing process is a key problem to be solved urgently for safety of the lead-based fast reactor, is an essential link for scientific research personnel to carry out experimental research, and provides an effective means for optimization design of a reactor structure, research on a flowing mechanism of the liquid metal and prevention and treatment of accidents.
On one hand, the application of most of traditional temperature measurement sensors is limited by high-temperature and high-pressure corrosive measurement environments, and on the other hand, the single-head temperature sensor cannot realize temperature field measurement of the whole section. Therefore, at present, a temperature sensor system which is resistant to high temperature and high pressure, corrosion-resistant, easy to process and wide in measurement dimension is urgently needed to be developed to realize accurate measurement of a cross-section temperature field in a liquid metal flowing process.
Patent document CN113865735A discloses a device and method for synchronously measuring speed and temperature of opaque liquid metal under magnetic field, which solves the problem of difficulty in speed measurement due to opaque property of liquid metal, and on this basis solves the problem of how to synchronously measure speed and temperature in liquid metal flow field in space and time. Due to the physical properties of liquid metal MHD flow, opacity, chemical corrosiveness and often high temperatures, and the presence of magnetic fields, accurate measurement of local velocities in liquid metal MHD flow requires special instrumentation. The invention uses potential probes made of two thermocouple wires to measure the induced potential generated by the liquid metal flow cutting magnetic induction line under the action of a magnetic field, so as to calculate the speed of the liquid metal, and obtains temperature signals at the same time and the same position through the electric signals of the thermocouple wires, thereby completing the synchronous measurement of the speed and the temperature of the liquid metal. This solution does not allow the measurement of the temperature field over the entire cross section of the flowing liquid metal.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide an optical fiber sensor and a measuring system for measuring the flow cross-section temperature field of liquid metal.
The optical fiber sensor for measuring the temperature field of the flow section of the liquid metal comprises an array optical fiber sensor, wherein the array optical fiber sensor comprises a buncher, an integrated board and N optical fiber temperature probes which are arranged on the integrated board in parallel, and N is more than 2;
the optical fiber temperature probe comprises a capillary tube, a coupler, a jumper wire head and M optical fiber gratings, wherein M is greater than 2;
the M fiber gratings are consistent in size and are fixedly arranged in the capillary close to one end of the capillary at equal intervals along the length direction of the capillary;
the other end of the capillary tube is connected with a jumper wire head through a coupler, and the jumper wire heads of the N optical fiber temperature probes are all connected with a buncher.
Preferably, an armor pipe is arranged between the coupler and the jumper head.
Preferably, the coupler includes a coupling bolt and a coupling nut that are matched with each other.
Preferably, a dustproof cap is detachably arranged on the jumper head.
Preferably, the capillary tube comprises a stainless steel capillary tube;
and the stainless steel capillary is subjected to leak detection and annealing treatment before being manufactured.
Preferably, the N fiber optic temperature probes are arranged equidistantly.
Preferably, the side surface of the integrated board is provided with N parallel slots, and the optical fiber temperature probes are correspondingly arranged in the slots one to one.
The measuring system for measuring the temperature field of the flow section of the liquid metal comprises a laser transmitter, a fiber grating analyzer, a data acquisition computer, a liquid metal container and a fiber sensor for measuring the temperature field of the flow section of the liquid metal;
a flow channel is arranged in the liquid metal container, the array type optical fiber sensor is positioned in the flow channel, and an integrated plate in the array type optical fiber sensor is arranged perpendicular to the flow channel;
the laser transmitter is arranged opposite to a buncher in the array type optical fiber sensor and can transmit an excitation laser signal;
the fiber bragg grating analyzer is in communication connection with the array type fiber optic sensor and can receive and analyze the temperature signal measured by the array type fiber optic sensor;
the data acquisition computer is in communication connection with the fiber grating analyzer and can store data analyzed by the fiber grating analyzer.
Preferably, the integrated plate is the same as the inner wall of the flow channel in material, and the size of the integrated plate is matched with that of the flow channel.
Preferably, the number of the array optical fiber sensors is multiple, and the array optical fiber sensors are uniformly arranged along the length direction of the flow channel;
the laser transmitters are arranged in one-to-one correspondence with the array type optical fiber sensors.
Compared with the prior art, the invention has the following beneficial effects:
1. the temperature measuring device is simple in structure and convenient to operate, realizes the measurement of the temperature in the high-temperature high-pressure corrosive liquid metal through the optical fiber temperature probe, and is beneficial to meeting the temperature measuring requirements in the fields of nuclear reactors and the like and the temperature measuring requirements of related scientific researchers during experimental research.
2. The invention adopts the technical means that the array-type optical fiber sensors are formed by the array-type arrangement of the optical fiber temperature probes, realizes the accurate measurement of the temperature on the flow section, the measurement dimension is expanded from one dimension to two dimensions, and adopts the technical means that a plurality of array-type optical fiber sensors are arranged on the flow channel, the measurement of the temperature field in the whole flow process is realized, and the measurement dimension is expanded to three dimensions.
3. According to the optical fiber temperature measurement principle, the measurement precision reaches +/-0.2 ℃, the response time reaches 100ms, the temperature sensitivity coefficient reaches 0.02979 nm/DEG C, the accurate temperature measurement is realized, and the method is not only suitable for measuring liquid metal, but also suitable for measuring a temperature field in an environment with normal temperature and normal pressure or common fluid.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic view of a measurement system according to the present invention;
FIG. 2 is a schematic top view of the fiber sensor of the present invention;
FIG. 3 is a schematic side view of the optical fiber sensor of the present invention;
FIG. 4 is a schematic diagram of a fiber optic temperature probe according to the present invention;
FIG. 5 is a graph showing the calibration results of the measurement accuracy of the fiber optic temperature probe.
The figures show that:
array type optical fiber sensor 1 capillary 9
The fiber grating analyzer 4 is connected with a nut 12
Buncher 6 jumper head 14
Optical fiber temperature probe 8
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will aid those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any manner. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the invention.
The invention discloses an optical fiber sensor and a measuring system for measuring a temperature field of a flow section of liquid metal, according to the optical fiber temperature measuring principle, the measuring precision reaches +/-0.2 ℃, the response time reaches 100ms, the temperature sensitivity coefficient reaches 0.02979 nm/DEG C, the accurate measurement of the temperature is realized, the invention is not only suitable for the measurement of the liquid metal, but also can be used for measuring the temperature field in the environment of normal temperature and normal pressure or common fluid.
According to the optical fiber sensor for measuring the flow cross-section temperature field of the liquid metal, as shown in fig. 2 and 3, the optical fiber sensor comprises an array type optical fiber sensor 1, wherein the array type optical fiber sensor 1 comprises a buncher 6, an integrated board 7 and N optical fiber temperature probes 8, N >; the N optical fiber temperature probes 8 are arranged at equal intervals. Preferably, the arrangement pitch of the optical fiber temperature probes 8 is 2mm.
Preferably, the side surface of the integrated board 7 is provided with N parallel slots, the optical fiber temperature probes 8 are correspondingly arranged in the slots one by one, the array type optical fiber sensor 1 is sealed after being manufactured, and no glue mark is left on the surface.
As shown in fig. 4, the fiber optic temperature probe 8 includes a capillary 9, a coupler, a jumper head 14, and M fiber gratings 10, M >; the M fiber gratings 10 are uniform in size and are fixedly arranged in the capillary 9 close to one end of the capillary 9 at equal intervals along the length direction of the capillary 9; the other end of the capillary 9 is connected with a jumper wire head 14 through a coupler, and the jumper wire heads 14 of the N optical fiber temperature probes 8 are all connected with the buncher 6. After the plurality of optical fiber temperature probes 8 are all installed on the integrated board 7, the buncher 6 is adopted to access and integrate the conducting wires, and the buncher 6 does not influence the signal excitation of the laser emitter 3.
An armored pipe 13 is arranged between the coupler and the jumper head 14. The coupler comprises a connecting bolt 11 and a connecting nut 12 which are matched with each other. The jumper head 14 is detachably provided with a dustproof cap 15. The capillary 9 comprises a stainless steel capillary 9; the stainless steel capillary 9 is subjected to leak detection and annealing treatment before being manufactured. The jumper head 14 comprises an FCAPC jumper head 14. And no glue mark is left on the surface of the optical fiber temperature probe 8.
The measuring system for measuring the temperature field of the flow section of the liquid metal comprises a laser transmitter 3, a fiber grating analyzer 4, a data acquisition computer 5, a liquid metal container and a fiber sensor for measuring the temperature field of the flow section of the liquid metal; a flow channel 2 is arranged in the liquid metal container, the array type optical fiber sensor 1 is positioned in the flow channel 2, and an integrated plate 7 in the array type optical fiber sensor 1 is arranged perpendicular to the flow channel 2;
the laser emitter 3 is arranged opposite to the buncher 6 in the array type optical fiber sensor 1 and can emit laser to carry out signal excitation, the signal changes under the influence of temperature at the measuring point of the fiber grating, and the fiber grating analyzer 4 is in communication connection with the array type optical fiber sensor 1 and can receive and analyze the temperature signal measured by the array type optical fiber sensor 1; the data acquisition computer 5 is in communication connection with the fiber grating analyzer 4 and can store data analyzed by the fiber grating analyzer 4. Thereby realizing the measurement of the temperature field of the flow section of the liquid metal. Preferably, the material of the integration plate 7 is the same as that of the inner wall of the flow channel 2, and the size of the integration plate 7 is matched with that of the flow channel 2.
The array type optical fiber sensors 1 are multiple, and the array type optical fiber sensors 1 are uniformly arranged along the length direction of the flow channel 2; the laser transmitters 3 are arranged in one-to-one correspondence with the array type optical fiber sensors 1. The temperature field measurement in the whole flowing process of the liquid metal is realized, and the measurement dimension is expanded to three dimensions.
The processing technology is not complex, the device is suitable for high-temperature and high-pressure severe environments with corrosiveness, and the three-dimensional temperature field information acquisition of the full-flow process is realized by arranging the plurality of array type optical fiber sensors 1 along the way.
Example 1
As shown in fig. 4, the optical fiber temperature probe 8 in the present embodiment includes a stainless steel capillary 9, M (M > 2) fiber gratings 10, a coupler, a jumper head 14, and a dust cap 15; the fiber gratings 10 are identical in size and are fixedly arranged in the stainless steel capillary 9 at equal intervals.
Leak detection and annealing treatment are carried out before the stainless steel capillary 9 is manufactured, the fiber bragg grating 10 is hermetically fixed inside the stainless steel capillary 9, the diameter of the stainless steel capillary 9 is 0.5mm, the diameter of the fiber bragg grating 10 is 0.155mm, the length of the fiber bragg grating is 2mm, and the arrangement interval is 1mm.
The coupler comprises a connecting bolt 11 and a connecting nut 12, sealing is carried out during connection, the size of the connecting bolt 11 is 1.3x20mm, and the size of the connecting nut 12 is 2.8x20mm.
The whole optical fiber temperature probe 8 is of a sealing structure, no glue mark is left on the surface, and the size of the armored pipe 13 is 2.3x200mm.
The working principle of the invention is as follows:
(1) And (3) grating temperature measurement principle. In the optical fiber temperature probe 8, the temperature is measured by using a fiber grating method, that is, the refractive index of the fiber core in the grating section is periodically changed, so that the light in the central wavelength range of the grating is reflected from the optical fiber, and the light in the rest wavelength ranges continuously propagates forwards along the optical fiber. The most general principle is shown in the following formula:
λ B ＝2η eff Λ
in the formula: λ B is the central wavelength of the reflection spectrum, η eff is the effective refractive index of the core region, and Λ is the period of the grating.
The fiber grating method uses a non-functional fiber sensor, i.e. a fiber sensor whose measurement principle does not depend on some sensitive characteristic of the fiber itself. In the working process of the grating, the period of the grating is changed due to the change of the external temperature, so that the central wavelength of the reflection spectrum is influenced, the change condition of the temperature is reflected through the influence degree of the wavelength, and the temperature measurement is realized.
(2) And (4) data acquisition principle. During the use, calibration is needed, the liquid metal with known temperature flows through the flow channel 12, the laser emitter 3 emits an excitation light signal, and the central wavelength of the reflection spectrum is recorded. And during formal measurement, measuring the offset of the central wavelength of the reflection spectrum under two working conditions to obtain the temperature change of the position of the grating under the two working conditions. The excitation light signal passes through the fiber grating 10 on the fiber temperature probe 8 in turn, and the offset change of the wavelength is obtained by analyzing on the fiber grating analyzer 4. The temperature field measurement on the flow section can be realized by exciting optical signals to a plurality of optical fiber temperature probes 8 on the array type optical fiber sensor 1 at the same time and adjusting by an analyzer. Since the signal response time is extremely short, the collected temperature information can be considered instantaneous.
The method is simple and convenient to operate, can complete parameter measurement of the three-dimensional temperature field in the liquid metal flowing process only by connecting the circuit, and can meet the real-time measurement requirements of the nuclear reactor field and related scientific research personnel on the flowing temperature of the liquid metal with high temperature, high pressure and strong corrosivity.
FIG. 5 shows that the invention has high precision, high sensitivity and strong applicability. The optical fiber temperature probe 8 and the measuring system provided by the invention simplify the probe manufacturing process and improve the measurement dimension, and simultaneously solve the problem of measuring the temperature of the liquid metal two-phase flow.
In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.
Claims (10)
1. An optical fiber sensor for measuring a temperature field of a flow section of liquid metal is characterized by comprising an array optical fiber sensor (1), wherein the array optical fiber sensor (1) comprises a buncher (6), an integrated board (7) and N optical fiber temperature probes (8) which are arranged on the integrated board (7) in parallel, and N is more than 2;
the optical fiber temperature probe (8) comprises a capillary tube (9), a coupler, a jumper head (14) and M optical fiber gratings (10), wherein M is more than 2;
the M fiber gratings (10) are consistent in size and are fixedly arranged in the capillary tube (9) close to one end at equal intervals along the length direction of the capillary tube (9);
the other end of the capillary tube (9) is connected with a jumper wire head (14) through a coupler, and the jumper wire heads (14) of the N optical fiber temperature probes (8) are all connected with the buncher (6).
2. The fiber optic sensor for measuring temperature field of flow cross section of liquid metal according to claim 1, characterized in that a sheathed tube (13) is provided between the coupler and the jumper head (14).
3. The fiber optic sensor for measuring temperature field of flow cross section of liquid metal according to claim 1, characterized in that the coupler comprises a coupling bolt (11) and a coupling nut (12) that are matched to each other.
4. The optical fiber sensor for measuring the temperature field of the flow section of liquid metal as claimed in claim 1, wherein a dust cap (15) is detachably arranged on the jumper head (14).
5. The fiber optic sensor of claim 1, wherein the capillary tube (9) comprises a stainless steel capillary tube (9);
the stainless steel capillary (9) is subjected to leak detection and annealing treatment before being manufactured.
6. Optical fiber sensor for measuring the temperature field of the flow cross section of a liquid metal according to claim 1, characterized in that said N optical fiber temperature probes (8) are arranged equidistantly.
7. The system for measuring the temperature field across the flow cross-section of liquid metal of claim 1, wherein the side of the integrated board (7) is provided with N parallel slots, and the optical fiber temperature probes (8) are arranged inside the slots in a one-to-one correspondence.
8. A measuring system for measuring a liquid metal flow cross section temperature field is characterized by comprising a laser transmitter (3), a fiber grating analyzer (4), a data acquisition computer (5), a liquid metal container and the fiber sensor for measuring the liquid metal flow cross section temperature field as claimed in any one of claims 1 to 7;
a flow channel (2) is arranged in the liquid metal container, the array type optical fiber sensor (1) is positioned in the flow channel (2), and an integrated plate (7) in the array type optical fiber sensor (1) is arranged perpendicular to the flow channel (2);
the laser transmitter (3) is arranged opposite to the buncher (6) in the array type optical fiber sensor (1) and can transmit an excitation laser signal;
the fiber bragg grating analyzer (4) is in communication connection with the array type fiber sensor (1) and can receive and analyze the temperature signal measured by the array type fiber sensor (1);
the data acquisition computer (5) is in communication connection with the fiber grating analyzer (4) and can store data analyzed by the fiber grating analyzer (4).
9. A measuring system for measuring the temperature field across the flow of liquid metal according to claim 8, characterised in that the manifold plate (7) is of the same material as the inner wall of the flow channel (2), the dimensions of the manifold plate (7) matching the flow channel (2).
10. A measuring system for measuring the temperature field across the flow of liquid metal according to claim 8, characterised in that said array of optical fibre sensors (1) is plural, the plural array of optical fibre sensors (1) being arranged uniformly along the length of the flow channel (2);
the laser transmitters (3) are arranged in one-to-one correspondence with the array type optical fiber sensors (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211433909.7A CN115717946A (en) | 2022-11-16 | 2022-11-16 | Optical fiber sensor and measuring system for measuring temperature field of flow section of liquid metal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211433909.7A CN115717946A (en) | 2022-11-16 | 2022-11-16 | Optical fiber sensor and measuring system for measuring temperature field of flow section of liquid metal |
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| CN115717946A true CN115717946A (en) | 2023-02-28 |
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| CN202211433909.7A Pending CN115717946A (en) | 2022-11-16 | 2022-11-16 | Optical fiber sensor and measuring system for measuring temperature field of flow section of liquid metal |
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| CN (1) | CN115717946A (en) |
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