Preparation method of probe type optical fiber gas pressure sensor

Abstract

The invention belongs to the technical field of optical fiber sensors, and particularly relates to a preparation method of a probe type optical fiber gas pressure sensor, which comprises the following steps: step 1, mixing an elastomer and a curing agent thereof, and processing to obtain a mixed solution; treating the Fe3O4-elastomer mixed solution to obtain a Fe3O4-elastomer mixed solution; step 3, filling the Fe3O4-elastomer mixed solution obtained in the step 2 into the first hollow-core optical fiber, and carrying out curing operation; forming the Fe3O4-elastomer magnetorheological elastomer; and step 4, finally, cutting and welding are carried out to obtain the section of the hollow-core optical fiber as a pressure sensing hole structure of the probe type optical fiber pressure sensor. The applicability of the optical fiber gas pressure sensor is improved, the sensing sensitivity is improved, and the high-performance optical fiber sensor is prepared on the basis of a magnetorheological elastomer membrane material; the method can be used in the fiber sensing field.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber sensors, and in particular relates to a method for preparing a probe type optical fiber gas pressure sensor. Background Art

[0002] Tunnel pulsation wind pressure testing is a key experimental technology used to simulate various aerodynamic conditions encountered by aircraft in actual flight, helping researchers to evaluate and optimize aircraft design and ensure the performance and structural stability of aircraft under high speed and different airflow conditions; traditional wind pressure measurements usually rely on mechanical sensors, but these devices have dynamic response limitations in high-frequency pulsation measurements; fiber optic sensors can accurately capture the rapidly changing pressure data generated in complex flow states, thereby providing a more detailed wind pressure distribution map, which is crucial for analyzing the aerodynamic load, vibration characteristics of the aircraft and its response to sudden airflow changes.

[0003] Fiber optic sensors detect various physical and chemical changes by utilizing the characteristics of optical fiber to conduct light waves. This type of sensor has the advantages of small size, light weight, strong anti-electromagnetic interference ability, and can work in extreme environmental conditions, such as high temperature, high pressure or corrosive environment. The core principle of fiber optic sensors is to sense changes in the external environment by monitoring the changes in the intensity, phase, polarization or wavelength of light passing through the optical fiber. The fiber optic sensor based on the Fabry-Perot interference principle (FP) forms an optical resonant cavity through two parallel reflection surfaces, one of which is fixed and the other moves with the change of gas pressure, thereby changing the optical path length of the cavity. When the gas pressure acts on the sensor probe, the movable reflection surface is displaced, resulting in changes in interference fringes. This change is transmitted to the optical signal demodulation device through the optical fiber to realize the quantitative detection of gas pressure. At present, the sensitivity, measurement range, response frequency and other characteristics of the fiber optic pressure sensor based on the FP principle are closely related to the material properties of the diaphragm. Once the material of the diaphragm is fixed, the sensing characteristics of the sensor cannot be adjusted by other methods, which limits the application scope of the pressure sensor to a certain extent.

[0004] Magnetorheological elastomer is a smart material composed of tiny magnetic particles suspended in a polymer matrix. The characteristic of this material is that its mechanical properties such as stiffness and damping performance can be changed rapidly and reversibly under the action of an external magnetic field. Due to these characteristics, magnetorheological elastomers show great application potential in the fields of vibration control, impact absorption and dynamic load adjustment. Using magnetorheological elastomer as the diaphragm material of the optical fiber pressure sensor based on the FP principle, the sensitivity, measurement range, response frequency and other characteristics of the sensor can be changed in real time and non-contact by changing the magnetic field applied to the outside of the sensor, thereby improving the performance and adaptability of the sensor. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a probe-type optical fiber gas pressure sensor, so as to realize a pulsating wind pressure sensor with small size, high frequency response, simple preparation and tunable sensitivity. Since the patent proposes an optical fiber gas pressure sensor based on the Fabry-Perot interference principle (FP), the diaphragm material is a high-reflectivity magnetorheological elastomer, and the Young's modulus of the diaphragm can be adjusted by changing the external magnetic field strength under non-contact conditions, thereby adjusting the sensor performance. It has more advantages than ordinary FP optical fiber pressure sensors in terms of adaptability to the measurement environment and sensitivity.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for preparing a probe-type optical fiber gas pressure sensor comprises the following steps:

[0008] Step 1: Mix the elastomer and its curing agent according to the formula, stir until the two are evenly mixed, and place the mixture under vacuum conditions for a certain period of time to obtain a mixed solution of the elastomer and its curing agent;

[0009] Step 2: Adding magnetic Fe3O4 particles with a particle size of 20 nm into the mixed solution obtained in step 1, and stirring until the magnetic particles are dispersed in the mixed solution, and after oscillation, obtaining a Fe3O4-elastomer mixed solution in which nanoparticles are evenly dispersed;

[0010] Step 3: Filling the Fe3O4-elastic mixed solution obtained in step 2 into the first hollow core optical fiber and performing a curing operation; the Fe3O4-elastic solution in the first hollow core optical fiber is cured to form a Fe3O4-elastic magnetorheological elastomer;

[0011] Step 4: Use a fiber fusion splicer to splice the second hollow-core fiber with the single-mode fiber; at the same time, the first hollow-core fiber filled with the Fe3O4-elastic magnetorheological elastomer obtained in step 3 is fused with the second hollow-core fiber: then place the spliced ​​fiber structure in Figure 2 The optical fiber precision cutting platform shown in the figure has both ends of the optical fiber fixed by optical fiber clamps. The fusion point between the hollow-core optical fiber and the optical fiber filled with material is found on the microscope camera. Then, by adjusting the translation distance L2=5μm of the three-dimensional displacement stage, the excess part of the optical fiber filled with material under the optical fiber cutting knife is used. The length of the optical fiber filled with material is L2, and it is used as the thickness of the Fe3O4-elastomer magnetorheological elastomer film. Finally, the first hollow-core optical fiber structure is spliced ​​again with a section of the third hollow-core optical fiber to obtain this section of hollow-core optical fiber as the pressure-sensing hole structure of the probe-type optical fiber pressure sensor.

[0012] Preferably, in step 1, the elastomer uses dimethylsiloxane, and the curing agent of dimethylsiloxane uses PDMS polydimethylsiloxane high-transparency curing agent or dibutyl phthalate; the mass ratio of dimethylsiloxane to its curing agent is 10:1.

[0013] Preferably, in step 1, the elastomer is rubber, the rubber curing agent is a yellowing-resistant curing agent or di-o-tolylguanidine, and the mass ratio of the rubber to the curing agent is 10:0.2-0.5.

[0014] Preferably, in step 1, the mixture of the elastomer and its curing agent is placed under vacuum for 10 minutes.

[0015] Preferably, in both step 1 and step 2, a glass rod is used to mix and stir the solution.

[0016] In the step 2, the oscillation method is to put the solution mixed with the magnetic particles into an ultrasonic oscillator and oscillate for 5 minutes to complete the uniform dispersion of the magnetic particles; in the present invention, the dispersion speed of the magnetic solution in the solution is accelerated by using an ultrasonic oscillator for oscillation.

[0017] Preferably, in step 3, the filling length is 1 mm; the curing operation is: placing the hollow-core optical fiber filled with the Fe3O4-elastomer mixed solution in a drying oven for curing, the temperature is set to 100°C, and the curing time is set to 1 hour.

[0018] Preferably, in step 4, the length of the second hollow-core optical fiber is L1=50 μm; the outer diameters of the first hollow-core optical fiber, the second hollow-core optical fiber and the third hollow-core optical fiber are 125 μm and the inner diameters are 75 μm.

[0019] The technical effects achieved by the present invention are:

[0020] The present invention uses magnetorheological elastomer as the diaphragm of the FP optical fiber pressure sensor. Compared with other types of FP optical fiber pressure sensors, the Young's modulus of the sensor diaphragm can be changed in real time and contactlessly by changing the external environmental magnetic field, thereby adjusting the performance of the sensor, and has greater flexibility.

[0021] At the same time, by using the optical fiber precision cutting platform, the reflection cavity length and the thickness of the magnetorheological elastomer diaphragm of the FP optical fiber pressure sensor can be precisely controlled, so that the sensor can obtain higher sensitivity; by changing the external environmental magnetic field, the sensitivity and measurement range of the sensor can be adjusted to enable it to match different pulsating pressure measurement environments.

[0022] The present invention improves the applicability of optical fiber gas pressure sensors, improves sensing sensitivity, and prepares high-performance optical fiber sensors based on magnetorheological elastomer diaphragm materials; the optical fiber sensors can be used in the field of optical fiber sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the probe type optical fiber gas pressure sensor of the present invention;

[0024] Figure 2 Schematic diagram of the high-precision optical fiber cutting platform of the present invention.

[0025] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0026] 1. Single-mode optical fiber; 2. Optical fiber fusion point; 3. Second hollow-core optical fiber; 4. Fe3O4-elastomer magnetorheological elastomer film; 5. First hollow-core optical fiber; 6. Optical fiber clamp; 7. Optical fiber cutting knife; 8. Microscope camera; 9. Adjustment of three-dimensional displacement stage; 10. Third hollow-core optical fiber. DETAILED DESCRIPTION

[0027] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present invention, and does not strictly limit the scope of protection of the specific claims of the present invention.

[0028] Embodiment 1:

[0029] like Figure 1 As shown, a method for preparing a probe-type optical fiber gas pressure sensor comprises the following steps:

[0030] Step 1: Mix dimethylsiloxane as an elastomer with its curing agent, the English abbreviation of dimethylsiloxane is PDMS; the curing agent of dimethylsiloxane uses PDMS polydimethylsiloxane high-transparency curing agent or dibutyl phthalate; the mass ratio of dimethylsiloxane and its curing agent is 10:1, and use a glass rod to stir until the two are evenly mixed, and place the mixture under vacuum conditions for a certain time, specifically the time the mixture is placed under vacuum is 10 minutes, to obtain a mixed solution of the elastomer and its curing agent;

[0031] Step 2: Put the magnetic Fe3O4 particles with a particle size of 20 nm into the mixed solution obtained in step 1, and stir with a glass rod until the magnetic particles are dispersed in the mixed solution. The oscillation method is to put the solution mixed with the magnetic particles into an ultrasonic oscillation instrument and oscillate for 5 minutes to complete the uniform dispersion of the magnetic particles. In the present invention, the dispersion speed of the magnetic solution in the solution is accelerated by oscillating with an ultrasonic oscillation instrument, and after oscillation, a Fe3O4-PDMS mixed solution with uniformly dispersed nanoparticles is obtained;

[0032] Step 3: Fill the Fe3O4-PDMS mixed solution obtained in step 2 into the first hollow-core optical fiber 5, with a filling length of 1 mm; and perform a curing operation; the curing operation is: place the hollow-core optical fiber filled with the Fe3O4-elastomer mixed solution in a drying oven for curing, the temperature is set to 100°C, and the curing time is set to 1 hour; the Fe3O4-PDMS solution in the first hollow-core optical fiber 5 is cured to form a Fe3O4-PDMS magnetorheological elastomer;

[0033] Step 4: Use a fiber fusion splicer to splice the second hollow-core fiber 3 with the single-mode fiber 1; at the same time, the first hollow-core fiber 5 filled with Fe3O4-PDMS magnetorheological elastomer obtained in step 3 is fused with the second hollow-core fiber 3: then place the spliced ​​fiber structure in Figure 2 The optical fiber precision cutting platform shown in the figure has both ends of the optical fiber fixed by the optical fiber clamp 6, and the fusion point between the hollow-core optical fiber and the optical fiber filled with material is found on the microscope camera 8, and then the translation distance L2=5μm is adjusted by adjusting the three-dimensional displacement stage 9, and the excess part of the optical fiber filled with material under the optical fiber cutting knife 7 is used. The length of the optical fiber filled with material is L2, and it is used as the thickness of the Fe3O4-elastomer magnetorheological elastomer film 4; in this embodiment, the Fe3O4-elastomer magnetorheological elastomer film 4 is a Fe3O4-PDMS magnetorheological elastomer film; finally, the first hollow-core optical fiber 5 structure is spliced ​​again with a section of the third hollow-core optical fiber 10, and this section of the hollow-core optical fiber is obtained as the pressure-sensing hole structure of the probe-type optical fiber pressure sensor.

[0034] In step 4, the length of the second hollow-core optical fiber 3 is L1 = 50 μm; the outer diameters of the first hollow-core optical fiber 5, the second hollow-core optical fiber 3 and the third hollow-core optical fiber 10 are 125 μm and the inner diameters are 75 μm.

[0035] Embodiment 2:

[0036] The difference between this embodiment and the first embodiment is that:

[0037] In step 1, the elastomer is rubber, the rubber curing agent is a yellowing-resistant curing agent or di-o-tolylguanidine, and the mass ratio of the rubber to the curing agent is 10:0.2-0.5.

[0038] It should be noted that if Figure 1 As shown, the single-mode optical fiber 1 and the second hollow-core optical fiber 3 are fused to obtain an optical fiber fusion point 2.

[0039] The present invention uses magnetorheological elastomer as the diaphragm of the FP optical fiber pressure sensor. Compared with other types of FP optical fiber pressure sensors, the Young's modulus of the sensor diaphragm can be changed in real time and contactlessly by changing the external environmental magnetic field, thereby adjusting the performance of the sensor, and has greater flexibility.

[0040] At the same time, the optical fiber precision cutting platform can precisely control the reflection cavity length and the thickness of the magnetorheological elastomer diaphragm of the FP optical fiber pressure sensor, so that the sensor can obtain higher sensitivity; by changing the external environmental magnetic field, the sensitivity and measurement range of the sensor can be adjusted to match different pulsating pressure measurement environments.

[0041] The present invention improves the applicability of optical fiber gas pressure sensors, improves sensing sensitivity, and prepares high-performance optical fiber sensors based on magnetorheological elastomer diaphragm materials; the optical fiber sensors can be used in the field of optical fiber sensing.

[0042] The above is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art unless otherwise specified and limited.

Claims

1. A method for preparing a probe-type optical fiber gas pressure sensor, characterized in that: The following steps are involved: Step 1: Mix the elastomer and its curing agent according to the formula, stir until the two are evenly mixed, and place the mixture under vacuum conditions for a certain period of time to obtain a mixed solution of the elastomer and its curing agent; Step 2: Adding magnetic Fe3O4 particles with a particle size of 20 nm into the mixed solution obtained in step 1, and stirring until the magnetic particles are dispersed in the mixed solution, and after oscillation, obtaining a Fe3O4-elastomer mixed solution in which nanoparticles are evenly dispersed; Step 3: Filling the Fe3O4-elastomer mixed solution obtained in step 2 into the first hollow core optical fiber (5), and performing a curing operation; the Fe3O4-elastomer solution in the first hollow core optical fiber (5) is cured to form a Fe3O4-elastomer magnetorheological elastomer; Step 4: Use a fiber fusion splicer to splice the second hollow-core optical fiber (3) with the single-mode optical fiber (1); at the same time, the first hollow-core optical fiber (5) filled with Fe3O4-elastic magnetorheological elastomer obtained in step 3 is fused with the second hollow-core optical fiber (3): then the spliced ​​optical fiber structure is placed on an optical fiber precision cutting platform, and both ends of the optical fiber are fixed by optical fiber clamps (6). The fusion point between the hollow-core optical fiber and the optical fiber filled with material is found on a microscope camera (8), and then the three-dimensional displacement stage (9) is adjusted to translate the distance L2 = 5μm. The excess part of the optical fiber filled with material under the optical fiber cutting knife (7) is used. The length of the optical fiber filled with material is L2 and is used as the thickness of the Fe3O4-elastic magnetorheological elastomer film (4); finally, the first hollow-core optical fiber (5) structure is spliced ​​again with a section of the third hollow-core optical fiber (10) to obtain this section of hollow-core optical fiber as a pressure-sensitive hole structure of a probe-type optical fiber pressure sensor.

2. The method for preparing a probe-type optical fiber gas pressure sensor according to claim 1, characterized in that: In the step 1, the elastomer uses dimethylsiloxane, and the curing agent of dimethylsiloxane uses PDMS polydimethylsiloxane high-transparency curing agent or dibutyl phthalate; the mass ratio of dimethylsiloxane to its curing agent is 10:

1.

3. The method for preparing a probe-type optical fiber gas pressure sensor according to claim 1, characterized in that: In step 1, the elastomer is rubber, and the rubber curing agent is a yellowing-resistant curing agent or di-o-tolylguanidine, and the mass ratio of the rubber to the curing agent is 10:0.2-0.

5.

4. The method for preparing a probe-type optical fiber gas pressure sensor according to claim 3 or 2, characterized in that: In the step 1, the mixture of the elastomer and the curing agent is placed under vacuum for 10 minutes.

5. The method for preparing a probe-type optical fiber gas pressure sensor according to claim 4, characterized in that: In both step 1 and step 2, a glass rod is used to mix and stir the solution.

6. The method for preparing a probe-type optical fiber gas pressure sensor according to claim 5, wherein in said step 2, the oscillation method is to put the solution mixed with magnetic particles into an ultrasonic oscillation instrument and oscillate for 5 minutes to achieve uniform dispersion of the magnetic particles.

7. The method for preparing a probe-type optical fiber gas pressure sensor according to claim 6, characterized in that: In the step 3, the filling length is 1 mm; the curing operation is: placing the hollow-core optical fiber filled with the Fe3O4-elastomer mixed solution in a drying oven for curing, the temperature is set to 100°C, and the curing time is set to 1 hour.

8. The method for preparing a probe-type optical fiber gas pressure sensor according to claim 7, characterized in that: In step 4, the length of the second hollow-core optical fiber (3) is L1=50 μm; the outer diameters of the first hollow-core optical fiber (5), the second hollow-core optical fiber (3) and the third hollow-core optical fiber (10) are 125 μm and the inner diameters are 75 μm.

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