High-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor

Abstract

The invention belongs to the technical field of high-temperature sensing, and particularly relates to a high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor which comprises a packaging base and a packaging cover plate, a sensing optical fiber and a sensitive diaphragm are arranged in the packaging base, a first Bragg grating and a second Bragg grating with different central wavelengths are arranged on the sensing optical fiber, and the first Bragg grating and the second Bragg grating are arranged on the packaging cover plate. The tail end of the sensing optical fiber is provided with a hollow-core optical fiber, the hollow-core optical fiber is provided with a punching area, temperature and vibration signals are measured through the Bragg gratings with two groups of different central wavelengths, and the tail end of the sensing optical fiber is provided with the punched hollow-core optical fiber to form a Fabry-Perot resonant cavity so as to test noise signals. Synchronous measurement of three parameters of heat, sound and vibration under the high-temperature condition is achieved, the consistency of measured data is high, and the device can be widely applied to high-temperature and high-pressure severe environments such as aerospace, missile launching and nondestructive testing.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature sensing such as aerospace, and particularly relates to a high-temperature-resistant fiber optic thermal-acoustic-vibration three-parameter sensor. Background Art

[0002] With the rapid development of aerospace technology, solid rockets have been widely used in commercial aerospace due to their unique advantages such as fast launch speed, high power, and low cost. However, during the operation of a solid rocket engine combustion chamber, high temperature, strong vibration, and strong noise have a significant impact on its structural stability, often causing irreversible damage to the engine structure and even triggering serious safety accidents. Currently, traditional electrical sensors are difficult to work properly in high-temperature environments due to material limitations, which greatly restricts their application in the monitoring of solid rocket engines.

[0003] Fiber optic sensors have been widely used in the measurement of multiple physical quantities in extremely harsh environments due to their strong anti-electromagnetic interference ability, long transmission distance, and high temperature resistance. Among them, sensors prepared based on fiber Bragg grating and fiber Fabry-Perot interference principles are the two most widely used types of fiber optic sensors. In the past few decades, fiber optic sensing technology has experienced rapid development and has been successfully applied to many key fields such as bridge monitoring, aerospace, petrochemical industry, etc. In practical applications, temperature, vibration, and noise, as crucial physical parameters, their changes often directly correlate with and reflect the operating state and safety of an object. However, fiber optic sensors at the current stage still have limitations. Fiber optic sensors usually can only achieve single-parameter in-situ measurement at a certain point, and it is still impossible to simultaneously obtain the three key physical parameters of temperature, vibration, and noise. This limitation greatly restricts the application range of fiber Bragg grating sensors in complex environments, making it necessary to use multiple sensors for separate measurements in situations where temperature, vibration, and noise need to be monitored simultaneously. This not only increases the complexity and cost of the system but also may lead to errors in measurement results due to the mutual influence between sensors.

[0004] Therefore, in order to better meet the actual needs of the aerospace field, it is necessary to improve the relevant sensor structure to achieve the synchronous acquisition of combustion temperature, vibration, and noise signals of solid rocket engines. Summary of the Invention

[0005] In order to overcome the problem that it is difficult for fiber optic sensors to effectively synchronously obtain temperature, vibration, and noise signals in high-temperature harsh environments in the prior art, the present invention proposes a high-temperature-resistant fiber optic thermal-acoustic-vibration three-parameter sensor to achieve accurate measurement of temperature, vibration, and noise signals in harsh environments such as high temperature and high pressure.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor, comprising: a packaging base and a packaging cover plate, wherein a first cavity is provided inside the packaging base; the packaging cover plate is arranged above the packaging base for packaging the first cavity;

[0007] A first through hole and a second through hole communicating with the first cavity are respectively arranged at two ends of the packaging base; a sensitive diaphragm groove for placing a sensitive diaphragm is arranged on the bottom surface of the first cavity, and a second cavity is arranged at the bottom of the sensitive diaphragm groove; both ends of the sensitive diaphragm are fixedly arranged in the sensitive diaphragm groove, and the first cavity and the second cavity form a vibration space for the sensitive diaphragm;

[0008] A sensing optical fiber is fixedly arranged at the bottom of the first cavity inside the packaging base, the end of the sensing optical fiber is arranged in the second through hole, and the other end extends to the outside of the packaging base through the first through hole after passing above the sensitive diaphragm; a first Bragg grating and a second Bragg grating with different central wavelengths are arranged on the sensing optical fiber, the first Bragg grating is fixed at the bottom of the first cavity, and the second Bragg grating is fixed on the sensitive diaphragm; an air-core optical fiber is arranged on one side of the sensing optical fiber close to the second through hole, a perforated area horizontally penetrating the fiber core is arranged on the air-core optical fiber, and both end faces of the air-core optical fiber form a Fabry-Perot resonator for measuring acoustic signals. The first Bragg grating and the second Bragg grating are respectively used for measuring temperature signals and vibration signals.

[0009] The sensitive diaphragm is in the shape of a cantilever beam, which includes triangular brackets on both sides and a cantilever beam in the center; the triangular brackets are arranged in the sensitive diaphragm groove, and the second cavity is located below the cantilever beam.

[0010] The sensitive diaphragm is fixed to the bottom surface of the sensitive diaphragm groove by a high-temperature inorganic adhesive.

[0011] A first optical fiber groove and a second optical fiber groove are further arranged at the bottom of the first cavity, and the first optical fiber groove and the second optical fiber groove are respectively located on both sides of the sensitive diaphragm groove for arranging the sensing optical fiber.

[0012] A cover plate groove is further arranged above the packaging base, and the cover plate groove matches the outer shape of the packaging cover plate for placing the packaging cover plate.

[0013] The high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor further includes an optical fiber armored tube, and the optical fiber armored tube is arranged in the first through hole for protecting the sensing optical fiber.

[0014] A first threaded hole perpendicular to the first through hole is arranged on the packaging base, and the first threaded hole is used for arranging a screw to fix the optical fiber armored tube.

[0015] A second threaded hole is arranged at the bottom of the packaging base, and the second threaded hole is used for arranging a screw to fix the sensor.

[0016] The materials of the sensitive diaphragm and the sensing optical fiber are both quartz, and the materials of the encapsulation base and the encapsulation cover are stainless steel.

[0017] The assembling method of the high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor includes the following steps:

[0018] Step S: Uniformly apply high-temperature inorganic glue between the sensitive diaphragm groove and the sensitive diaphragm, place the sensitive diaphragm in the sensitive diaphragm groove, and use an oven to bake to cure the high-temperature inorganic glue;

[0019] Step S: Uniformly apply high-temperature inorganic glue at the positions where the sensing optical fiber contacts the encapsulation base and the quartz sensitive diaphragm, place the sensing optical fiber on the encapsulation base and the sensitive diaphragm, and use an oven to bake to cure the high-temperature inorganic glue;

[0020] Step S: Thread the optical fiber armored tube outside the sensing optical fiber and extend it into the first through hole of the encapsulation base, and use screws to fixedly connect the optical fiber armored tube and the encapsulation base;

[0021] Step S: Use a spot welder to fixedly connect the encapsulation cover and the encapsulation base by spot welding around the periphery.

[0022] The present invention has the following beneficial effects compared with the prior art:

[0023] 1. The present invention provides a high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor, which uses two groups of Bragg gratings with different central wavelengths to measure temperature and vibration signals, and forms a Fabry-Perot resonator by arranging a perforated hollow optical fiber at the end of the sensing optical fiber to measure noise signals; specifically, the first Bragg grating is pasted on the surface of the encapsulation base and is only sensitive to temperature. By observing the drift amount of the central wavelength of its reflection signal, the actual temperature change can be detected. At the same time, the second Bragg grating is pasted on the surface of the quartz sensitive diaphragm and is sensitive to both vibration and temperature. By observing the drift amount of the central wavelength of its reflection signal, the change of the superposition of the actual temperature and vibration can be detected. In addition, the hollow optical fiber forming the Fabry-Perot resonator is pasted at the end of the encapsulation base and is sensitive to noise signals. By monitoring the free spectral range of its reflection spectrum, the detection of noise signals can be realized. By using the first Bragg grating to compensate for the influence of temperature on the second Bragg grating, the magnitudes of temperature, vibration, and noise signals in the environment can be simultaneously calculated. Therefore, the present invention can realize the synchronous measurement of thermal-acoustic-vibration three parameters under high-temperature conditions through a simple structure, and the consistency of the measurement data is strong.

[0024] 2. The present invention realizes the encapsulation of the sensing core device through an encapsulation cover plate and an encapsulation base, and the encapsulation materials are all made of 310S stainless steel, achieving a fully rigid connection of the sensor device, ensuring the stability of the optical sensing signal of the sensor in different temperature, vibration, and noise environments, and helping to improve the test accuracy of the sensor in high-temperature environments.

[0025] In summary, the present invention realizes the synchronous monitoring of temperature, vibration, and noise signals for the first time, breaks through the working temperature limit of traditional sensors, realizes the integration of multiple physical parameters, and has practical application value in harsh environments such as aerospace, missile launch, and non-destructive testing with high temperature and high pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the external structure of a high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor provided by an embodiment of the present invention;

[0027] Figure 2 It is a schematic diagram of the internal structure of a high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor provided by an embodiment of the present invention;

[0028] Figure 3 It is a schematic cross-sectional structure of a high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor provided by an embodiment of the present invention;

[0029] Figure 4 It is a schematic three-dimensional structure diagram of the encapsulation base in an embodiment of the present invention;

[0030] Figure 5 It is a schematic partial structure diagram of the hollow-core fiber with holes in the sensing optical fiber in an embodiment of the present invention;

[0031] Figure 6 It is a schematic structure diagram of the sensitive diaphragm in an embodiment of the present invention;

[0032] Figure 7 It is a reflection spectrum diagram of the sensing optical fiber obtained in an embodiment of the present invention;

[0033] In the figure: 1 - encapsulation cover plate, 2 - encapsulation base, 3 - sensitive diaphragm, 4 - optical fiber armor tube, 5 - sensing optical fiber, 21 - second threaded hole, 22 - first threaded hole, 23 - second cavity, 24 - first cavity, 25 - second through hole, 26 - sensitive diaphragm groove, 27 - first optical fiber groove, 28 - first through hole, 29 - cover plate groove, 210 - second optical fiber groove, 31 - triangular bracket, 32 - cantilever beam, 51 - first Bragg grating, 52 - second Bragg grating, 53 - hollow-core fiber, 54 - drilling area. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] As Figures 1 to 4 shown, an embodiment of the present invention provides a high-temperature-resistant fiber optic thermal-acoustic-vibration three-parameter sensor, including: a packaging base 1 and a packaging cover plate 2. A first cavity 24 is provided in the packaging base 1; the packaging cover plate 2 is arranged above the packaging base 1 and is used to package the first cavity 24.

[0036] Among them, a first through hole 28 and a second through hole 25 communicating with the first cavity 24 are respectively arranged at two ends of the packaging base 1; a sensitive diaphragm groove 26 for placing a sensitive diaphragm 3 is arranged on the bottom surface of the first cavity 24, and a second cavity 23 is arranged at the bottom of the sensitive diaphragm groove 26; the sensitive diaphragm 3 is fixedly arranged in the sensitive diaphragm groove 26, and the first cavity 24 and the second cavity 23 form a vibration space for the sensitive diaphragm 3.

[0037] Among them, a sensing optical fiber 5 is fixedly arranged in the packaging base 1. The end of the sensing optical fiber 5 is arranged in the second through hole 25, and the other end extends to the outside of the packaging base 1 through the first through hole 28 after passing above the sensitive diaphragm 3; first Bragg gratings 51 and second Bragg gratings 52 with different central wavelengths are arranged on the sensing optical fiber 5. The first Bragg grating 51 is fixed at the bottom of the first cavity 24, and the second Bragg grating 52 is fixed on the sensitive diaphragm 3. The first Bragg grating 51 and the second Bragg grating 52 are respectively used to measure temperature signals and vibration signals.

[0038] As Figure 5 shown, in this embodiment, a hollow optical fiber 53 fixed to the bottom of the first cavity 24 is arranged on one side of the sensing optical fiber 5 close to the second through hole 25. End faces of the hollow optical fiber 53 form a Fabry-Perot resonator, and a perforated area 54 penetrating the optical fiber core transversely is arranged on the hollow optical fiber 53. An external sound pressure signal enters the first cavity 24 through the second through hole 25 and is further transmitted to the Fabry-Perot resonator through the perforated area 54. Then, the Fabry-Perot resonator is sensitive to noise, and noise signal measurement can be realized by monitoring the change in the free spectral range of the Fabry-Perot resonator.

[0039] Specifically, in this embodiment, the method for setting the hollow-core optical fiber 53 is as follows: Use an optical fiber fusion splicer to fuse a section of hollow-core optical fiber 53 at the end of the sensing optical fiber 5, and then fuse a section of sensing optical fiber 5 at the end of the hollow-core optical fiber 53. Fabry-Perot resonators are formed at both ends of the hollow-core optical fiber 53. Finally, the hollow-core optical fiber 53 is drilled by a femtosecond laser to obtain a drilling area 54 to achieve the propagation of the sound pressure signal to the Fabry-Perot resonator. Specifically, in this embodiment, the core diameter of the hollow-core optical fiber 53 used is 75 μm, the cladding diameter is 125 μm, and the length is about 800 μm. The length of the drilling area 54 is 60 μm, and the width is 30 μm.

[0040] In addition, in this embodiment, both the first Bragg grating 51 and the second Bragg grating 52 are fabricated by femtosecond laser processing, which can ensure that the gratings will not be erased due to high-temperature environments and have the advantages of stability and high reliability.

[0041] Specifically, as Figure 6 shown, in this embodiment, the sensitive diaphragm 3 is in the shape of a cantilever beam, which includes triangular brackets 31 on both sides and a cantilever beam 32 in the center; as Figure 2 shown, the triangular brackets 31 are arranged in the sensitive diaphragm groove 26, and the second cavity 23 is located below the cantilever beam 32. The length of the second cavity 23 is slightly greater than the length of the cantilever beam 32 to ensure that the cantilever beam 32 is completely suspended, thereby enhancing the vibration sensitivity of the sensor, and the triangular brackets 31 at both ends of the sensitive diaphragm 3 are fixed on the bottom surface of the sensitive diaphragm groove 26.

[0042] Specifically, in this embodiment, the depth of the sensitive diaphragm groove 26 is greater than or equal to the thickness of the sensitive diaphragm 3, and the sensitive diaphragm 3 is fixed on the bottom surface of the sensitive diaphragm groove 26 by high-temperature inorganic glue.

[0043] Specifically, both the first through hole 28 and the second through hole 25 are square.

[0044] Specifically, in this embodiment, a first optical fiber groove 27 and a second optical fiber groove 210 are further provided at the bottom of the first cavity 24. The first optical fiber groove 27 and the second optical fiber groove 210 are respectively located on both sides of the sensitive diaphragm groove 26 and are used for arranging the sensing optical fiber 5.

[0045] Specifically, in this embodiment, the first Bragg grating 51 in the sensing optical fiber 5 is fixed in the first optical fiber groove 27 by high-temperature inorganic glue and is only sensitive to temperature. By measuring the drift of the central wavelength of its reflected light, the actual temperature change can be detected. The second Bragg grating 52 in the sensing optical fiber 5 is fixed together with the sensitive diaphragm 3 by high-temperature inorganic glue. Under the vibration of the sensitive diaphragm 3, the second Bragg grating 52 is sensitive to both temperature and vibration signals. By observing the drift of the central wavelength of the reflected light of the second Bragg grating 52, the change of the superposition of the actual temperature and vibration can be detected. Then, by using the offset of the central wavelength of the reflected light of the first Bragg grating 51 to compensate the second Bragg grating 52, the magnitude of the vibration signal can be calculated. Therefore, this embodiment can simultaneously measure the temperature and the magnitude of the vibration signal in the environment.

[0046] Specifically, in this embodiment, the hollow optical fiber 53 in the sensing optical fiber 5 is fixed in the second optical fiber groove 210 on the packaging base 1 by high-temperature inorganic glue.

[0047] Further, as Figure 4 shown, in this embodiment, a cover plate groove 29 is further provided above the packaging base 1. The cover plate groove 29 matches the shape of the packaging cover plate 2 and is used to place the packaging cover plate 2. In this embodiment, the packaging base 1 and the packaging cover plate 2 are tightly connected by spot welding.

[0048] Further, as Figure 4 shown, a high-temperature resistant fiber optic thermal-acoustic-vibration three-parameter sensor in this embodiment further includes an optical fiber armor tube 4. The optical fiber armor tube 4 is arranged in the first through hole 28 and is used to protect the sensing optical fiber 5.

[0049] Further, as Figure 4 shown, a first threaded hole 22 perpendicular to the first through hole 28 is provided on the packaging base 1. The first threaded hole 22 is used to set a screw to fix the optical fiber armor tube 4.

[0050] Further, as Figure 3 shown, a second threaded hole 21 is provided at the bottom of the packaging base 1. The second threaded hole 21 is used to set a screw to realize the fixed connection between the sensor and the object to be measured.

[0051] Specifically, in this embodiment, the materials of the sensitive diaphragm 3 and the sensing optical fiber 5 are both quartz, and the materials of the packaging base 1 and the packaging cover plate 2 are stainless steel.

[0052] In addition, the assembly method of the high-temperature resistant fiber optic thermal-acoustic-vibration three-parameter sensor in this embodiment includes the following steps:

[0053] Step S1: Uniformly apply high-temperature inorganic glue between the sensitive diaphragm groove 26 and the sensitive diaphragm 3, place the sensitive diaphragm 3 in the sensitive diaphragm groove 26, and use an oven to bake to cure the high-temperature inorganic glue;

[0054] Step S2: Using the full-pasting method, uniformly apply high-temperature inorganic glue at the positions where the sensing optical fiber 5 contacts the packaging base 1 and the quartz sensitive diaphragm 3, place the sensing optical fiber 5 on the packaging base 1 and the sensitive diaphragm 3, and use an oven to bake to cure the high-temperature inorganic glue;

[0055] Step S3: Thread the optical fiber armored tube 4 outside the sensing optical fiber 5 and extend it into the first through hole 28 of the packaging base 1, and use an M2 screw to fixedly connect the optical fiber armored tube 4 to the packaging base 1;

[0056] Step S4: Spot-weld and fixedly connect the packaging cover plate 2 and the packaging base 1 around through a spot welder.

[0057] In this embodiment, a group of first Bragg gratings 51 with a central wavelength of 1545 nm and a group of second Bragg gratings 52 with a central wavelength of 1550 nm are inscribed inside the sensing optical fiber 5 by a femtosecond laser. The tail end of the sensing optical fiber 5 is fusion-spliced with a hollow optical fiber 53 using an optical fiber fusion splicer, and a section of sensing optical fiber is fusion-spliced after the hollow optical fiber 53 to form a Fabry-Perot resonator. When the light output from the amplified spontaneous emission light source is sent into the sensing optical fiber 5 through the circulator, and the reflected light generated in the sensing optical fiber 5 enters the spectrometer through the circulator, the reflected spectrum generated by the sensing optical fiber 5 is detected by the spectrometer. As Figure 7 shown, the obtained reflected spectrum includes the reflection peaks of the first Bragg grating 51 and the second Bragg grating 52. By the central drift of the two reflection peaks, the temperature and vibration signals can be demodulated respectively. At the same time, through the change of the free spectral range of the reflected spectrum, the noise signal can also be demodulated. Therefore, the present invention can realize the synchronous measurement of thermal-acoustic-vibration parameters in a high-temperature environment.

[0058] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-temperature resistant fiber optic thermal-acoustic-vibration three-parameter sensor, characterized in that, Comprising: An encapsulation base (1) and an encapsulation cover plate (2), wherein a first cavity (24) is provided inside the encapsulation base (1); The encapsulation cover plate (2) is arranged above the encapsulation base (1) for encapsulating the first cavity (24); At both ends of the encapsulation base (1), a first through hole (28) and a second through hole (25) communicating with the first cavity (24) are respectively provided; on the bottom surface of the first cavity (24), a sensitive diaphragm groove (26) for placing a sensitive diaphragm (3) is provided, and a second cavity (23) is provided at the bottom of the sensitive diaphragm groove (26); both ends of the sensitive diaphragm (3) are fixedly arranged in the sensitive diaphragm groove (26), and the first cavity (24) and the second cavity (23) form a vibration space for the sensitive diaphragm (3); A sensing optical fiber (5) is fixedly arranged at the bottom of the first cavity (24) inside the encapsulation base (1), the end of the sensing optical fiber (5) is arranged in the second through hole (25), and the other end extends to the outside of the encapsulation base (1) through the first through hole (28) after passing above the sensitive diaphragm (3); on the sensing optical fiber (5), a first Bragg grating (51) and a second Bragg grating (52) with different central wavelengths are provided, the first Bragg grating (51) is fixed at the bottom of the first cavity (24), and the second Bragg grating (52) is fixed on the sensitive diaphragm (3); on one side of the sensing optical fiber (5) close to the second through hole (25), a hollow-core optical fiber (53) is provided, a perforation area (54) penetrating the optical fiber core transversely is provided on the hollow-core optical fiber (53), and both end faces of the hollow-core optical fiber (53) form a Fabry - Perot resonator for measuring acoustic signals, and the first Bragg grating (51) and the second Bragg grating (52) are respectively used for measuring temperature signals and vibration signals.

2. The high-temperature resistant optical fiber thermal-acoustic-vibration three-parameter sensor according to claim 1, wherein The sensitive diaphragm (3) is in the shape of a cantilever beam, and it includes triangular brackets (31) on both sides and a cantilever beam (32) in the center; the triangular brackets (31) are arranged in the sensitive diaphragm groove (26), and the second cavity (23) is located below the cantilever beam (32).

3. The high-temperature resistant optical fiber thermal-acoustic-vibration triple-parameter sensor according to claim 1, wherein The sensitive diaphragm (3) is fixed on the bottom surface of the sensitive diaphragm groove (26) by a high-temperature inorganic adhesive.

4. The high-temperature resistant fiber optic thermal-acoustic-vibration three-parameter sensor according to claim 1, characterized in that On the bottom of the first cavity (24), a first optical fiber groove (27) and a second optical fiber groove (210) are further provided, and the first optical fiber groove (27) and the second optical fiber groove (210) are respectively located on both sides of the sensitive diaphragm groove (26) for arranging the sensing optical fiber (5).

5. The high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor according to claim 1, wherein Above the encapsulation base (1), a cover plate groove (29) is further provided, and the cover plate groove (29) matches the outer shape of the encapsulation cover plate (2) for placing the encapsulation cover plate (2).

6. The high-temperature resistant fiber optic thermal-acoustic-vibration three-parameter sensor according to claim 1, characterized in that, An optical fiber armored tube (4) is further included, and the optical fiber armored tube (4) is arranged in the first through hole (28) for protecting the sensing optical fiber (5).

7. The high-temperature resistant optical fiber thermal-acoustic-vibration three-parameter sensor according to claim 6, wherein, On the encapsulation base (1), a first threaded hole (22) perpendicular to the first through hole (28) is provided, and the first threaded hole (22) is used for setting a screw to fix the optical fiber armored tube (4).

8. The high-temperature resistant fiber optic thermal-acoustic-vibration three-parameter sensor according to claim 6, wherein, On the bottom of the encapsulation base (1), a second threaded hole (21) is provided, and the second threaded hole (21) is used for setting a screw to fix the sensor.

9. The high-temperature resistant optical fiber thermal-acoustic-vibration triple-parameter sensor according to claim 1, characterized in that, The materials of the sensitive diaphragm (3) and the sensing optical fiber (5) are both quartz, and the materials of the packaging base (1) and the packaging cover plate (2) are stainless steel.

10. A high-temperature-resistant optical fiber thermal-acoustic-vibration three-parameter sensor according to claim 1, characterized in that, Its assembly method includes the following steps: Step S1: Uniformly apply high-temperature inorganic glue between the sensitive diaphragm groove (26) and the sensitive diaphragm (3), place the sensitive diaphragm (3) in the sensitive diaphragm groove (26), and use an oven to bake to cure the high-temperature inorganic glue; Step S2: Uniformly apply high-temperature inorganic glue at the positions where the sensing optical fiber (5) contacts the packaging base (1) and the quartz sensitive diaphragm (3), place the sensing optical fiber (5) on the packaging base (1) and the sensitive diaphragm (3), and use an oven to bake to cure the high-temperature inorganic glue; Step S3: Thread the optical fiber armored tube (4) outside the sensing optical fiber (5) and extend it into the first through hole (28) of the packaging base (1), and use screws to fixedly connect the optical fiber armored tube (4) to the packaging base (1); Step S4: Use a spot welder to fixedly connect the packaging cover plate (2) and the packaging base (1) by spot welding around the perimeter.

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