Solid rocket engine lining curing detection method based on fiber bragg grating

Abstract

The invention discloses a solid rocket engine lining curing detection method based on a fiber Bragg grating, which comprises the following steps: S1, preparing lining slurry according to process requirements, spraying or blade-coating the lining slurry on a heat insulation surface according to engine technical index requirements, and feeding into a curing oven for constant-temperature rotary curing; s2, a detection device is sent into the engine, and the detection device is placed on the surface of the lining layer; and S3, acquiring the signal change of the grating sensor in the detection process by utilizing an optical fiber detection system, and judging the curing state of the lining according to detection data and a data processing algorithm. Based on the advantages of small size, high precision, low cost, intrinsic safety and the like of the fiber bragg grating, physical characteristics such as strain, temperature, pressure and the like of the structure can be effectively detected, the defects of large occupied area, high price and the like of ultrasonic, infrared ray and other methods and equipment are overcome, and in-situ and nondestructive detection of the curing state of the lining is realized.

Description

Technical Field

[0001] The invention relates to the field of nondestructive testing, and in particular to a solid rocket engine lining curing detection method based on fiber Bragg grating. Background Art

[0002] Solid rocket engines are the main power devices of today's aerospace equipment. The liner is an important bonding transition layer between the propellant and the insulation layer in the engine combustion chamber. Its bonding performance directly affects the quality of the charge and has an important impact on the integrity of the engine structure and its working reliability.

[0003] The curing process of the lining is a long-term, gentle phase change process from liquid phase to solid phase. During the curing process, the thickness, morphology, viscoelasticity, density, impedance, modulus and other characteristic parameters of the lining will change to varying degrees. Its appearance changes from the initial viscous flow state to the drawing state, then to the slightly sticky "semi-cured" state, and finally to a non-sticky and fully cured state. According to the changes in the physical and appearance properties of the lining during the curing process, existing research has developed ultrasonic methods, manual methods and infrared spectroscopy methods to detect the curing process of the lining, but the above methods have limitations such as high price, complex operation, and inability to detect in situ. Summary of the invention

[0004] The present invention provides a solid rocket engine lining curing detection method based on fiber Bragg grating, which effectively solves the problems of high price, complicated operation and insufficient or excessive curing easily caused by manual judgment in traditional methods.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A solid rocket engine lining curing detection method based on fiber Bragg grating includes the following detection steps:

[0007] S1. Prepare lining slurry according to process requirements, spray or scrape the lining slurry on the insulation surface according to engine technical indicators, and send it into a curing furnace for constant temperature rotation curing;

[0008] S2. Send the detection device into the engine and place it on the surface of the lining;

[0009] S3. Use the optical fiber detection system to obtain the changes in the grating sensor signal during the detection process, and determine the curing state of the lining layer based on the detection data and data processing algorithm.

[0010] As a preferred embodiment of the above scheme, in step S1, the lining is a solid engine lining, including conventional linings of HTPB / IPDI and HTPB / TDI thermal curing systems and novel linings.

[0011] As a preferred embodiment of the above scheme, in step S2, the detection device includes a grating sensor, a fiber clamp, a counterweight, and a fiber cutter. The grating sensor is clamped by the fiber clamp, a counterweight is provided on the top of the fiber clamp, and a fiber cutter is provided on the inner wall of one side of the fiber clamp.

[0012] As a preferred embodiment of the above scheme, in step S2, a constant clamping force is pre-applied to the grating sensor through the optical fiber clamp, the grating sensor is in direct contact with the lining layer, and the grating sensor is buried in the lining layer through a counterweight block.

[0013] As a preferred embodiment of the above scheme, in step S2, for engines of the same model, size and lining manufacturing process, the diameter of the grating sensor carried by the detection device, the coating, and the clamping force applied by the detection device to the sensor, i.e., the weight of the counterweight block, remain consistent.

[0014] As a preferred embodiment of the above solution, step S2 specifically includes:

[0015] S21, clamping the grating sensor in the optical fiber holder, the center of the grating area and the center of gravity of the counterweight block are on the same straight line, and the sensor clamping force is controlled by a micromotor;

[0016] S22, select a suitable position of the inner lining of the solid rocket engine, send the detection device to the designated position, press down the counterweight block, and bury the grating sensor in the lining;

[0017] S23, using a fiber optic cutter to cut one side of the grating sensor, and connecting the other side of the grating sensor to the fiber optic detection system.

[0018] As a preferred embodiment of the above scheme, in step S3, the optical fiber detection system includes a demodulation module and a data analysis module that are interconnected. The demodulation module is connected to the grating sensor to measure the optical fiber signal generated by the retraction of the grating sensor in the lining layer and transmit the data to the data analysis module.

[0019] As a preferred embodiment of the above solution, in step S3, the lining curing detection is realized by using the signal data generated by the retraction of the grating sensor in the lining.

[0020] As a preferred embodiment of the above solution, step S3 specifically includes:

[0021] S31. According to multiple test experiments, the optical fiber signal data during the process of the lining layer changing from liquid phase to solid phase is obtained, and the normalized curves λ(t) and k(t) of the grating wavelength change Δλ and the wavelength change rate k during the retraction process and the lining layer curing time are respectively established, and the curve ψ(t) of the curing index and the curing time during the lining layer curing process is constructed;

[0022] S32, install the optical fiber detection system in the engine of the same model and size, obtain the sensor model characteristics during the sensor retraction process, and calculate the measured curing index ψ(t i ), by comparing and analyzing ψ(t i ) and ψ(t) to determine the current lining solidification state.

[0023] As a preferred embodiment of the above scheme, the grating wavelength change Δλ=|λ 1 -λ 2 |, where λ 1 is the wavelength value after the sensor is implanted into the interface, λ 2 is the wavelength value of the sensor after shearing and retraction stabilization; the grating wavelength change rate k = Δλ / ΔT, where ΔT is the retraction time of the sensor in the lining; the curing index ψ(t) = λ(t)+k(t), where t is time.

[0024] Due to the above structure, the beneficial effects of the present invention are:

[0025] (1) Based on the advantages of fiber Bragg grating, such as small size, high precision, low cost, and intrinsic safety, the present invention can effectively detect physical characteristics of the structure, such as strain, temperature, and pressure. The grating sensor is implanted in the lining layer, and the physical characteristics of the viscosity change during the curing process of the lining layer are used to analyze the signal generated by the retraction of the grating sensor in the lining layer. The defects of ultrasonic and infrared ray methods, such as large equipment space and high price, are overcome, and the in-situ and non-destructive detection of the curing state of the lining layer can be realized.

[0026] (2) The present invention conducts in-depth analysis on the grating signal data, extracts the grating signal characteristics caused by the viscosity during the grating retraction process, and quantitatively analyzes the curing state of the lining, thereby solving the problem of insufficient or excessive curing caused by manual judgment, and provides scientific support for subsequent processes such as charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below.

[0028] Figure 1 It is a curing detection flow chart of the present invention;

[0029] Figure 2 It is a schematic diagram of the detection device of the present invention;

[0030] Figure 3 This is a schematic diagram of the lining curing judgment principle of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, this embodiment provides a solid rocket engine lining curing detection method based on fiber Bragg grating, including the following detection steps:

[0033] S1. Prepare lining slurry according to process requirements, spray (scrape) the lining slurry on the insulation surface according to engine technical indicators, and send it into a curing furnace for constant temperature rotation curing; the lining is a solid engine lining, including conventional linings and new linings of HTPB / IPDI and HTPB / TDI thermal curing systems, that is, all linings involving liquid to solid phase transition can adopt the method of the present invention.

[0034] S2, sending the detection device 000 into the engine, and placing the detection device 000 on the surface of the lining; wherein, Figure 2 As shown, the detection device 000 includes a grating sensor 001, a fiber clamp 002, a counterweight 003, and a fiber cutter 4. The grating sensor 001 is clamped by the fiber clamp 002, and the counterweight 003 is provided on the top of the fiber clamp 002, and the fiber cutter 4 is provided on the inner wall of one side of the fiber clamp 002. The grating sensor 001 is pre-applied with a constant clamping force by the fiber clamp 002, and the grating sensor 001 is directly in contact with the lining layer, and the grating sensor 001 is buried in the lining layer through the counterweight 003. For engines of the same model, size and lining manufacturing process, the diameter, coating of the grating sensor 001 carried by the detection device 000, and the clamping force applied to the sensor by the detection device 000, that is, the weight of the counterweight 003, are consistent. Specifically, the following steps are included:

[0035] S21. Clamp the grating sensor 001 in the optical fiber holder 002, with the center of the grating area and the center of gravity of the counterweight block 003 on the same straight line. The clamping force of the sensor is controlled by a micromotor. The sensors (diameter, coating) and clamping force implanted in solid rocket engines of the same model and size are kept consistent;

[0036] S22, select a suitable position of the inner lining of the solid rocket engine, send the detection device 000 to the designated position, press down the counterweight 003, bury the grating sensor 001 in the lining, and keep the weight and action time of the solid rocket engine counterweight 003 of the same model and size consistent;

[0037] S23, use the optical fiber cutter 4 to cut off one side of the grating sensor 001, and the other side of the grating sensor 001 is connected to the optical fiber detection system. After the measurement is completed, the counterweight block 003 is pulled up and the optical fiber detection device 000 is withdrawn.

[0038] S3. Use the optical fiber detection system to obtain the signal change of the grating sensor 001 during the detection process, and judge the curing state of the lining layer according to the detection data and the data processing algorithm. The optical fiber detection system includes a demodulation module 100 and a data analysis module 200 which are connected to each other. The demodulation module 100 is connected to the grating sensor 001 to measure the optical fiber signal generated by the grating sensor 001 retracting in the lining layer, and transmit the data to the data analysis module 200. The signal data generated by the grating sensor 001 retracting in the lining layer is used to realize the curing detection of the lining layer. Specifically, the following steps are included:

[0039] S31. For a certain type and size of engine lining, install a fiber optic detection system to obtain fiber optic signal data during the process of the lining changing from liquid to solid. The test results of grating sensor 001 are as follows: Figure 3 As shown, the wavelength value of the grating sensor 001 after implantation into the interface is λ 1 , the wavelength value after shear retraction is stable is λ 2 , the sensor retraction time is ΔT, calculate the grating wavelength change Δλ=λ 1 -λ 2 | and wavelength change rate k = Δλ / ΔT. During the curing process of the engine lining of this model and size, multiple tests were conducted to establish the normalized curves λ(t) and k(t) of Δλ, k and curing time t during the curing process of the lining, and to construct the curve of curing index and curing time ψ(t) during the curing process of the lining. The i-th test index ψ(t i )=λ(t i )+k(t i )) to analyze the lining curing index threshold value ψ within the lining optimal bonding performance period 1 With ψ 2 , ψ 1 < 2 ;

[0040] S32, install the optical fiber detection system in the engine of the same model and size, obtain the sensor model characteristics during the sensor retraction process, and calculate the measured curing index ψ(t i ), by comparing ψ(t i ) and ψ(t) to determine the current lining solidification state.

[0041] This embodiment is based on the advantages of fiber Bragg grating such as small size, high precision, low cost, and intrinsic safety. It can effectively detect physical characteristics of the structure such as strain, temperature, and pressure. The grating sensor is implanted in the lining layer, and the physical characteristics of the viscosity change during the lining curing process are used to analyze the signal generated by the retraction of the grating sensor in the lining layer. This overcomes the defects of ultrasonic and infrared methods such as large equipment space and high price, and realizes in-situ and non-destructive detection of the curing state of the lining.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A solid rocket engine lining curing detection method based on fiber Bragg grating, characterized in that: The following detection steps are included: S1. Prepare lining slurry according to process requirements, spray or scrape the lining slurry on the insulation surface according to engine technical indicators, and send it into a curing furnace for constant temperature rotation curing; S2. Send the detection device into the engine and place it on the surface of the lining; S3. Use the optical fiber detection system to obtain the changes in the grating sensor signal during the detection process, and determine the curing state of the lining layer based on the detection data and data processing algorithm.

2. The solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 1 is characterized in that: In step S1, the lining is a solid engine lining, including conventional linings of HTPB / IPDI and HTPB / TDI thermal curing systems and novel linings.

3. The solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 1 is characterized in that: In step S2, the detection device includes a grating sensor, a fiber clamp, a counterweight, and a fiber cutter. The grating sensor is clamped by the fiber clamp, a counterweight is provided on the top of the fiber clamp, and a fiber cutter is provided on the inner wall of one side of the fiber clamp.

4. The solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 1 is characterized in that: In step S2, a constant clamping force is pre-applied to the grating sensor through the optical fiber clamp, the grating sensor is in direct contact with the lining layer, and the grating sensor is buried in the lining layer through the counterweight block.

5. The solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 1, characterized in that: In step S2, for engines of the same model, size and lining manufacturing process, the diameter of the grating sensor carried by the detection device, the coating, and the clamping force applied by the detection device to the sensor, i.e., the weight of the counterweight block, remain consistent.

6. The solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 1, characterized in that: Step S2 specifically includes: S21, clamping the grating sensor in the optical fiber holder, the center of the grating area and the center of gravity of the counterweight block are on the same straight line, and the sensor clamping force is controlled by a micromotor; S22, select a suitable position of the inner lining of the solid rocket engine, send the detection device to the designated position, press down the counterweight block, and bury the grating sensor in the lining; S23, using a fiber optic cutter to cut one side of the grating sensor, and connecting the other side of the grating sensor to the fiber optic detection system.

7. The solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 1 is characterized in that: In step S3, the optical fiber detection system includes a demodulation module and a data analysis module which are interconnected. The demodulation module is connected to the grating sensor to measure the optical fiber signal generated by the grating sensor retracting in the lining layer and transmit the data to the data analysis module.

8. The solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 1, characterized in that: In step S3, the lining layer solidification detection is implemented using the signal data generated by the grating sensor retracting in the lining layer.

9. The solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 1, characterized in that: Step S3 specifically includes: S31. According to multiple test experiments, the optical fiber signal data during the process of the lining layer changing from liquid phase to solid phase is obtained, and the normalized curves λ(t) and k(t) of the grating wavelength change Δλ and the wavelength change rate k during the retraction process and the lining layer curing time are respectively established, and the curve ψ of the curing index and the curing time during the lining layer curing process is constructed. ( t ) ; S32. Install the optical fiber detection system in the engine of the same model and size, obtain the sensor model characteristics during the sensor retraction process, and calculate the measured curing index ψ corresponding to the i-th test ( t i) , by comparing and analyzing ψ ( t i) With ψ ( t ) Determine the current lining curing status.

10. A solid rocket engine lining curing detection method based on fiber Bragg grating according to claim 9, characterized in that: Grating wavelength change Δλ= | λ1-λ 2| , where λ1 is the wavelength value after the sensor is implanted into the interface, λ2 is the wavelength value after the sensor is sheared and retracted to stabilize; grating wavelength change rate k = Δλ / ΔT, where ΔT is the retraction time of the sensor in the lining; curing index ψ ( t ) =λ ( t ) +k ( t ) , where t is time.

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