A method of integrating optical fiber temperature sensing components inside insulation materials

Abstract

This invention relates to a method for integrating fiber optic temperature sensing components into thermal insulation materials. Specifically, it relates to the field of composite material structure technology / smart composite materials, and more specifically to a method for integrating fiber optic temperature sensing components into thermal insulation materials. This invention addresses the technical problem of high interfacial bonding strength, which significantly affects the thermal insulation performance of materials, encountered in existing technologies for integrating optical fibers into thermal insulation materials. The method includes: 1. Pre-embedding and integrating the optical fiber; 2. Preparing a low-concentration polymer solution; 3. Constructing a weak interface. This invention causes less damage to the material and has a wider range of applications; it achieves a synergistic effect of "precise fixing of measuring points - high temperature measurement accuracy"; the pore structure inside the thermal insulation material has little impact on the material's thermal insulation performance, thus better preserving the pore structure inside the thermal insulation material. This invention is used to prepare temperature sensing components.

Description

Technical Field

[0001] This invention relates to the field of composite material structure technology / smart composite materials, and specifically to a method for integrating fiber optic temperature sensing components into the interior of thermal insulation materials. Background Technology

[0002] Thermal insulation materials, characterized by high temperature resistance, low density, and low thermal conductivity, have been widely used in aerospace, energy, and other fields. However, during service, these materials are highly susceptible to damage from impacts, overheating, and other extreme conditions, leading to a decline in their thermal insulation performance and severely impacting the overall structural reliability. The internal temperature field of a material is one of the effective parameters reflecting its internal structural state. After impact delamination or overheating damage, the temperature field data of the damaged area shows anomalies compared to the normal area. Against this backdrop, researchers have proposed integrating sensing components within the thermal insulation material to obtain real-time temperature data from different measurement points inside the material and to deduce changes in the internal temperature field to assess the material's condition. This allows for timely replacement of materials that do not meet service requirements, thereby improving the overall structural reliability.

[0003] Currently, the sensors used for internal temperature measurement of thermal insulation materials mainly include thermocouples and optical fibers. Among them, thermocouples have advantages such as high temperature measurement accuracy and wide temperature measurement range, and have been widely used. However, thermocouples are difficult to achieve distributed measurement, and their diameter is relatively large (generally >1mm). If high-density temperature measurement points are arranged inside the material, it will inevitably cause the material performance to degrade. In comparison, fiber optic sensors have advantages such as being thin (diameter ~100μm), having strong resistance to electromagnetic interference, and enabling distributed measurement (a single fiber can achieve multiple measurement points). They have received widespread attention in recent years. Existing methods for embedding optical fibers into porous materials mostly involve integrating the optical fiber into the material through drilling / pre-embedding, then injecting a small amount of epoxy resin into the porous material, and finally fixing the optical fiber inside the material after curing. However, with this method, the optical fiber is prone to forming a tight bond with the material. During the heating process, due to the difference between the thermal expansion coefficient of the material and the optical fiber, strain will inevitably be transferred to the optical fiber, resulting in low temperature measurement accuracy. Furthermore, the introduction of a large amount of resin can easily cause a decline in the thermal insulation performance of the material, making it difficult to meet the requirements of practical engineering applications. Summary of the Invention

[0004] To address the technical problem of high interfacial bonding strength, which significantly affects the thermal insulation performance of materials when integrating optical fibers into thermal insulation materials, this invention proposes a technical solution based on a "weak interface" structure for integrating optical fiber sensing components into thermal insulation materials.

[0005] A method for integrating fiber optic temperature sensing components into thermal insulation materials comprises the following steps:

[0006] 1. Pre-embedded integration of optical fibers: Integrate optical fibers into the thermal insulation material and temporarily fix the optical fibers with adhesive;

[0007] II. Preparation of low-concentration polymer solution: Mix the solvent and polymer evenly to form a low-concentration polymer solution;

[0008] III. Construction of weak interfaces: The position where the optical fiber is fixed inside the insulation material in step one is placed in the low-concentration polymer solution obtained in step two for full immersion. After drying and curing, the integration of the optical fiber temperature sensing component inside the insulation material is realized.

[0009] This invention proposes a method for integrating optical fiber temperature sensing components into thermal insulation materials. By impregnating, drying, and curing a low-concentration polymer at the point where the optical fiber is integrated into the thermal insulation material, a weak interface with a porous structure is formed between the optical fiber and the thermal insulation material, thus achieving the integrated integration of the thermal insulation material and the porous material.

[0010] Compared with existing technologies, the advantages are as follows:

[0011] (1) The present invention can integrate fiber optic temperature sensing components inside the insulation material, and the measurement point position and fiber arrangement are highly selectable. Compared with the traditional thermocouple temperature measurement method, it can integrate high-density temperature measurement points inside the insulation material, which causes less damage to the material and has a wider range of applications.

[0012] (2) The porous weak interface between the optical fiber and the heat insulation material formed by the present invention can provide a certain adhesion force for the optical fiber inside the heat insulation material, avoid the relative sliding of the optical fiber during the service of the material, and prevent the measurement point position from being deviated. Compared with the strong interface formed between the traditional resin and the optical fiber, the porous weak interface can largely alleviate the influence of the strain caused by the mismatch between the thermal expansion coefficient of the heat insulation material and the optical fiber on the optical fiber temperature measurement data during temperature change, and realize the synergy of "precise fixing of measurement point - high temperature measurement accuracy".

[0013] (3) In the impregnation process, the present invention uses a low-concentration polymer solution for impregnation. After drying and curing, the material still has a high porosity. Compared with the traditional method, it better preserves the pore structure inside the thermal insulation material and has no significant impact on the thermal insulation performance of the material. This avoids the problem of significant degradation of the thermal insulation performance of the material caused by the large amount of filling of the pores of the thermal insulation material in the traditional method.

[0014] This invention is used to prepare temperature sensing components. Attached Figure Description

[0015] Figure 1 This is an image of the fiber optic temperature sensing component integrated into the thermal insulation material, obtained in Example 2.

[0016] Figure 2 These are spectral images of the changes in fiber optic signals at multiple measurement points under room temperature conditions for the fiber optic temperature sensing component integrated into the thermal insulation material, as prepared in Example 2. Detailed Implementation

[0017] Specific Implementation Method 1: This implementation method describes a method for integrating fiber optic temperature sensing components into thermal insulation materials, specifically following these steps:

[0018] 1. Pre-embedded integration of optical fibers: Integrate optical fibers into the thermal insulation material and temporarily fix the optical fibers with adhesive;

[0019] II. Preparation of low-concentration polymer solution: Mix the solvent and polymer evenly to form a low-concentration polymer solution;

[0020] III. Construction of weak interfaces: The position where the optical fiber is fixed inside the insulation material in step one is placed in the low-concentration polymer solution obtained in step two for full immersion. After drying and curing, the integration of the optical fiber temperature sensing component inside the insulation material is realized.

[0021] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the method of integrating optical fibers into the thermal insulation material described in step one includes:

[0022] If the thermal insulation material is a porous composite material prepared by braiding, then during the braiding process, optical fibers are braided into the interior of the material; or after braiding, channels are obtained by mechanically drilling holes to introduce optical fibers.

[0023] If the insulation material is a composite material prepared by a high-temperature heat treatment method, a channel is obtained by mechanically drilling holes to introduce the optical fiber. Other aspects are the same as in the specific implementation method.

[0024] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the optical fiber integration and arrangement method in the thermal insulation material in step one is as follows: when arranging the optical fiber, the minimum bending radius of the optical fiber is controlled to be greater than the allowable radius of the optical fiber. Everything else is the same as in Specific Implementation Method One or Two.

[0025] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the temporary fixing method for the optical fiber in step one is as follows:

[0026] For optical fibers arranged in a straight line, glue is used to fix the beginning and end points;

[0027] If the optical fiber needs to be wound from the outside of the material during the layout process, grooves should be pre-processed on the outside of the material, and the optical fiber should be fixed with glue at the critical endpoints on the bending path. Other aspects are the same as in one of the specific implementation methods 1 to 3.

[0028] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the optical fiber mentioned in step one is a quartz optical fiber, sapphire optical fiber, or gold-plated quartz optical fiber. Everything else is the same as in Specific Implementation Methods One to Four.

[0029] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the solvent used in step two is methanol, ethanol, or acetone. Otherwise, it is the same as Specific Implementation Methods One to Five.

[0030] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the polymer described in step two is a phenolic resin or a polycarbosilane. Otherwise, it is the same as Specific Implementation Methods One to Six.

[0031] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the mass concentration of the low-concentration polymer solution in step two is 1.5% to 30%. Everything else is the same as in Specific Implementation Methods One to Seven.

[0032] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: the drying method in step three is atmospheric pressure drying or vacuum drying, and the drying temperature is 40–90°C. Everything else is the same as in Specific Implementation Methods One to Eight.

[0033] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that the curing process in step three is performed using an oven, with a curing temperature of 90–240°C. All other aspects are the same as in Specific Implementation Methods One to Nine.

[0034] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

[0035] The beneficial effects of the present invention are verified using the following embodiments:

[0036] Example 1:

[0037] This embodiment describes a method for integrating fiber optic temperature sensing components into thermal insulation materials, which is specifically carried out according to the following steps:

[0038] I. Pre-embedded integration of optical fibers: The thermal insulation material is carbon fiber thermal insulation felt prepared by weaving. During the weaving process, quartz optical fibers are woven into the material. The quartz optical fibers are arranged in a straight line from two opposite center points inside the carbon fiber thermal insulation felt without bending. Adhesive is used to temporarily fix the beginning and end points of the optical fibers to ensure the accuracy of the measuring point position.

[0039] 2. Preparation of low-concentration polymer solution: Methanol and phenolic resin are mixed evenly to form a methanol solution of phenolic resin with a concentration of 1.5 wt.%.

[0040] III. Construction of weak interfaces: The position where the optical fiber is fixed inside the carbon fiber thermal insulation felt in step one is placed in the methanol solution of phenolic resin obtained in step two for full immersion. Then, it is placed in an oven for drying at 40°C and normal pressure and curing at 90°C to realize the integration of optical fiber temperature sensing components into the thermal insulation material.

[0041] Example 2:

[0042] This embodiment describes a method for integrating fiber optic temperature sensing components into thermal insulation materials, which is specifically carried out according to the following steps:

[0043] I. Pre-embedded integration of optical fibers: The heat insulation material is carbon fiber heat insulation felt prepared by weaving. After weaving, gold-plated quartz optical fibers are introduced by mechanically drilling holes to provide a channel for the optical fibers. The optical fibers are arranged in a straight line from two opposite center points inside the felt without bending. The beginning and end points of the optical fibers are temporarily fixed with glue to ensure the accuracy of the measuring point position.

[0044] 2. Preparation of low-concentration polymer solution: Ethanol and phenolic resin are mixed evenly to form an ethanol solution of phenolic resin with a concentration of 7.5 wt.%.

[0045] III. Construction of weak interfaces: The position where the optical fiber is fixed inside the carbon fiber thermal insulation felt in step one is placed in the ethanol solution of phenolic resin obtained in step two for full immersion. Then, it is placed in an oven for vacuum drying at 40°C and curing at 120°C to achieve the integration of optical fiber temperature sensing components inside the thermal insulation material.

[0046] Figure 1 The image shows the optical fiber temperature sensing component integrated into the thermal insulation material as obtained in Example 2. As can be seen from the image, one gold-plated quartz optical fiber is integrated along the material normal and one in the in-plane direction.

[0047] Figure 2 The image shows the spectral changes of fiber optic signals at multiple measurement points under surface heating at 600°C for the fiber optic temperature sensing element integrated into the thermal insulation material obtained in Example 2. As can be seen from the image, the measurement data along the in-plane direction did not shift, indicating that the internal temperature of the material remained consistent along the in-plane direction. However, the measurement data along the normal direction showed differences with temperature changes. This is because the internal temperature of the material away from the heating surface gradually decreased during the single-sided heating test, which is consistent with the actual situation.

[0048] Example 3:

[0049] This embodiment describes a method for integrating fiber optic temperature sensing components into thermal insulation materials, which is specifically carried out according to the following steps:

[0050] I. Pre-embedded integration of optical fibers: The heat insulation material is a ceramic heat insulation tile prepared by high-temperature heat treatment. After weaving, the sapphire optical fiber is introduced by mechanically drilling holes to provide a channel for the optical fiber. Because it is necessary to meet the requirement of multiple measurement points not on the same straight line, the optical fiber needs to be wound from the outside of the ceramic heat insulation tile. Therefore, grooves are processed on the outside of the material where the optical fiber passes, and the optical fiber is fixed with glue at the key endpoints on the bending path to ensure the accuracy of the measurement point position.

[0051] 2. Preparation of low-concentration polymer solution: Mix acetone and polycarbosilane uniformly to form an acetone solution of polycarbosilane with a concentration of 15 wt.%.

[0052] III. Construction of weak interfaces: The position where the integrated optical fiber is fixed inside the ceramic heat insulation tile in step one is placed in the acetone solution of polycarbonylsilane obtained in step two for full immersion. Then, it is placed in an oven for drying at 90°C and normal pressure and curing at 240°C to realize the integration of optical fiber temperature sensing components inside the heat insulation material.

[0053] Example 4:

[0054] This embodiment describes a method for integrating fiber optic temperature sensing components into thermal insulation materials, which is specifically carried out according to the following steps:

[0055] I. Pre-embedded integration of optical fibers: The thermal insulation material is carbon fiber thermal insulation felt prepared by weaving. After weaving, sapphire optical fibers are introduced by mechanically drilling holes to provide a channel for the optical fibers. The optical fibers are arranged in a straight line from two opposite center points inside the felt without bending. Adhesive is used to temporarily fix the beginning and end points of the optical fibers to ensure the accuracy of the measuring point position.

[0056] 2. Preparation of low-concentration polymer solution: Ethanol and phenolic resin are mixed evenly to form an ethanol solution of phenolic resin with a concentration of 22.5 wt.%.

[0057] III. Construction of weak interfaces: The position where the optical fiber is fixed inside the carbon fiber thermal insulation felt in step one is placed in the ethanol solution of phenolic resin obtained in step two for full immersion. Then, it is placed in an oven for vacuum drying at 60°C and curing at 180°C to achieve the integration of optical fiber temperature sensing components inside the thermal insulation material.

[0058] Example 5:

[0059] I. Pre-embedded integration of optical fibers: The heat insulation material is a ceramic heat insulation tile prepared by high-temperature heat treatment. After weaving, gold-plated quartz optical fibers are introduced by mechanically drilling holes to provide a channel for the optical fibers. Because it is necessary to meet the requirement of multiple measurement points not on the same straight line, the optical fibers need to be wound from the outside of the ceramic heat insulation tile. Therefore, grooves are processed on the outside of the material where the optical fibers pass, and the optical fibers are fixed with glue at the key endpoints on the bending path to ensure accurate measurement point positions.

[0060] 2. Preparation of low-concentration polymer solution: Mix acetone and polycarbosilane uniformly to form an acetone solution of polycarbosilane with a concentration of 30 wt.%.

[0061] III. Construction of weak interfaces: The position where the optical fiber is fixed inside the ceramic heat insulation tile in step one is placed in the acetone solution of polycarbonylsilane obtained in step two for full immersion. Then, it is placed in an oven for vacuum drying at 90℃ and curing at 180℃ to realize the integration of optical fiber temperature sensing components into the heat insulation material.

Claims

1. A method of integrating an optical fiber temperature sensing component inside an insulation material, characterized by This method is specifically carried out in the following steps:

1. Pre-embedded integration of optical fibers: Integrate optical fibers into the thermal insulation material and temporarily fix the optical fibers with adhesive; II. Preparation of low-concentration polymer solution: Mix the solvent and polymer evenly to form a low-concentration polymer solution; III. Construction of a weak interface with a porous structure: The position where the optical fiber is fixed inside the insulation material in step one is placed in the low-concentration polymer solution obtained in step two for full immersion. After drying and curing, the integration of the optical fiber temperature sensing component inside the insulation material is realized. The polymer mentioned in step two is a phenolic resin or a polycarbosilane; The mass concentration of the low-concentration polymer solution mentioned in step two is 1.5~30%.

2. A method of integrating an optical fiber temperature sensing component inside a thermal insulation material according to claim 1, characterized in that The method of integrating optical fibers into the thermal insulation material as described in step one includes: If the thermal insulation material is a porous composite material prepared by braiding, then during the braiding process, optical fibers are braided into the interior of the material; or after braiding, channels are obtained by mechanically drilling holes to introduce optical fibers. If the insulation material is a composite material prepared by a high-temperature heat treatment method, then a channel is obtained by mechanically drilling holes to introduce the optical fiber.

3. The method for integrating optical fiber temperature sensing components into a thermal insulation material according to claim 1, characterized in that... In step one, the optical fiber is integrated and arranged in the thermal insulation material as follows: when arranging the optical fiber, the minimum bending radius of the optical fiber is controlled to be greater than the allowable radius of the optical fiber.

4. The method for integrating optical fiber temperature sensing components into a thermal insulation material according to claim 1, characterized in that... The temporary fixing method for the optical fiber mentioned in step one is as follows: For optical fibers arranged in a straight line, glue is used to fix the beginning and end points; If optical fibers need to be wound from the outside of the material during the layout process, grooves are pre-processed on the outside of the material, and adhesive is used to fix the optical fibers at the critical endpoints on the bending path.

5. The method for integrating optical fiber temperature sensing components into a thermal insulation material according to claim 1, characterized in that... The optical fiber mentioned in step one is sapphire optical fiber or gold-plated quartz optical fiber.

6. The method for integrating optical fiber temperature sensing components into a thermal insulation material according to claim 1, characterized in that... The solvent used in step two is methanol, ethanol, or acetone.

7. The method for integrating optical fiber temperature sensing components into a thermal insulation material according to claim 1, characterized in that... Step 3 involves drying under normal pressure or under vacuum, at a temperature of 40-90℃.

8. The method for integrating optical fiber temperature sensing components into a thermal insulation material according to claim 1, characterized in that... The curing process described in step three involves heating in an oven at a temperature of 90~240℃.

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