A device and method for testing the content of a solid propellant binder in a composite solid propellant grain

Abstract

The application provides a testing device and method for the content of a solidifying agent in a composite solid propellant slurry, and particularly relates to a sampling device for a composite solid propellant slurry, an adjustable pressure device of an infrared spectrometer and a testing method for the content of a solidifying agent in a composite solid propellant slurry, which can test the content of the solidifying agent in the propellant slurry with different solidification degrees. The application has the characteristics of simple method and convenient operation, and the sampling device and the pressure adjusting device have the characteristics of novel design and easy operation, can improve the testing precision of the infrared spectroscopy method, improve the accuracy of quantitative analysis data, establish a testing method for the content of a solidifying agent in a composite solid propellant slurry, provide a new method for monitoring the change rule of the content of the solidifying agent in the solidification process of the slurry, provide a quantitative basis for studying the solidification degree of the interface between the propellant and the lining, and provide data support for solving the interface debonding of the solid propellant.

Description

Technical Field

[0001] This application relates to the technical field of testing the curing agent content of composite solid propellant slurry, and in particular to a sampling device for composite solid propellant slurry, an adjustable pressure device for an infrared spectrometer, and a method for testing the curing agent content of composite solid propellant slurry. Background Technology

[0002] Solid composite propellants are energetic composite materials based on polymers and possessing specific properties; they are the energy source for solid rocket engines. Adhesion failure is one of the most common failure modes in solid rocket engines. This failure is attributed to physical and chemical changes in the materials during bonding and storage, which can lead to debonding of the propellant and liner, causing engine malfunction.

[0003] Composite solid propellants typically use isocyanates as curing agents. During the curing process, the degree to which the curing agent isocyanate forms a cross-linked network with the polymer materials in the propellant significantly affects the interfacial adhesion between the propellant and the liner. However, the rapid reaction rate of isocyanate with various propellant components during curing makes long-term monitoring of isocyanate in the propellant slurry impossible. Therefore, there is an urgent need to establish a rapid and simple method for detecting the curing agent content in composite solid propellant slurry, providing a new approach for monitoring the changes in curing agent content during the slurry curing process. Summary of the Invention

[0004] To address the issue of the inability to monitor the curing agent content of composite solid propellant slurry over extended periods, this application provides a simple and rapid method for testing the curing agent content of propellant slurry, and also provides a propellant slurry sampling device and an adjustable pressure device for the sample cell of an infrared spectrometer with multiple internal reflection accessories, thereby improving the accuracy of infrared spectroscopy testing.

[0005] In one aspect, a sampling device for composite solid propellant slurry is provided, including an adjusting handle, an upper cover, a pressurizing chamber, a slider, and a storage chamber;

[0006] The pressurizing chamber is connected between the upper cover and the storage chamber. The upper cover is used to seal the opening of the pressurizing chamber away from the storage chamber. The inner cavity of the pressurizing chamber is in communication with the storage space of the storage chamber. The inner diameter of the space in which the pressurizing chamber and the storage chamber communicate with each other is the same.

[0007] The adjusting handle extends into the pressurization chamber through the inlet of the upper cover;

[0008] The slider is located at one end of the adjusting handle inside the pressurizing chamber, and the slider is in close contact with the inner wall of the pressurizing chamber or the storage chamber.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the adjusting handle and the inlet thread are engaged.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the material extruded by the sampling device satisfies Wherein, V is the amount of slurry fluid extruded, θ is the rotation angle of the adjusting handle, P is the thread pitch of the adjusting handle, and S is the cross-sectional area of ​​the slider.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the adjusting handle includes a handle portion and a moving rod; the handle portion is located on the side of the upper cover away from the pressurization chamber, and the outer diameter of the handle portion is larger than the inner diameter of the inlet; the moving rod cooperates with the inlet, and the inner diameter of the moving rod is smaller than the inner diameter of the pressurization chamber.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, a sealing ring is provided on the slider, the slider is sealed to the pressurization chamber by the sealing ring, and the slider is sealed to the storage chamber by the sealing ring.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the connection between the pressurization chamber and the storage chamber is sealed by a sealing ring.

[0014] Secondly, an adjustable pressure device for an infrared spectrometer is provided, the device comprising: an adjusting handle, a screw, a top plate, a positioning pin, a set screw, a retaining ring, a pressure plate, a spring, a base plate, and a pressure plate;

[0015] The adjusting handle is connected to the screw, which passes through the center hole of the top plate and engages with the retaining spring. The top plate is supported on the bottom plate by the positioning pin. The space between the top plate and the bottom plate is used to accommodate the pressure plate and the spring. The retaining spring is used to apply pressure to the pressure plate to cause the spring to deform. The set screw fixes the bottom plate to the infrared multiple internal reflection accessory sample cell. The pressure plate is used to apply pressure to the infrared multiple internal reflection accessory sample cell under the action of the spring.

[0016] In conjunction with the second aspect, in some implementations of the second aspect, pressure is applied to satisfy:

[0017] Wherein, F is the pressure applied by the adjustable pressure device to the infrared multiple internal reflection accessory sample cell, k is the spring coefficient of the spring, θ is the rotation angle of the adjusting handle, and P is the thread pitch of the screw.

[0018] Thirdly, a method for testing the content of curing agent in composite solid propellant slurry is provided, including:

[0019] Step 1: Select the composite solid propellant slurry to be tested and determine the curing temperature;

[0020] Step 2: Under set temperature conditions, Fourier transform infrared spectroscopy was used to test the composite solid propellant slurry with different curing reaction times.

[0021] Step 3: Using Fourier transform infrared spectroscopy to test the results, establish a model for the change in curing agent content during the curing process of the propellant slurry;

[0022] Step 4: Calculate the curing agent content corresponding to the curing reaction time of the same propellant slurry without Fourier transform infrared spectroscopy test based on the model.

[0023] In conjunction with the third aspect, in some implementations of the third aspect, step 2 specifically includes:

[0024] Step 2-1: Using the sampling device described in any of the implementation methods of the first aspect above, take an appropriate amount of sample and coat the sample cell of the infrared multiple internal reflection accessory.

[0025] Step 2-2: Use a Fourier transform infrared spectrometer, with 16–64 scans and a resolution of 4 cm⁻¹. -1 The wavelength range is 4000cm. -1 ~650cm -1 The sample cell is pressurized by an adjustable pressure device as described in any of the second aspects above, and an infrared spectrum is obtained. The infrared spectral data is stored in the form of absorbance.

[0026] In conjunction with the third aspect, in some implementations of the third aspect, step 3 specifically includes:

[0027] Step 3-1: Process the infrared spectral data. Select one of the following: original spectrum, first derivative spectrum, or second derivative spectrum. Select one of the following: no smoothing, SG smoothing, or Norris smoothing for the smoothing method.

[0028] Step 3-2: Establish a quantitative model, using one or more of the following methods: Beer-Lambert law, least squares (CLS), stepwise multiple linear regression, partial least squares (PLS), and principal component regression (PCR).

[0029] Step 3-3: Establish a model for the content of the slurry curing agent.

[0030] This application solves the problem of the inability to monitor the content of curing agent in composite solid propellant slurry for extended periods, establishes a simple and rapid method for testing the curing agent content in propellant slurry, and provides a propellant slurry sampling device and an adjustable pressure testing device for the sample cell of an infrared spectrometer with multiple internal reflection accessories, thereby improving the accuracy of infrared spectroscopy testing.

[0031] This application features a simple method and convenient operation. The sampling device and pressure testing device are novel in design and easy to operate. It can improve the accuracy of infrared spectroscopy testing, enhance the accuracy of quantitative analysis data, establish a testing method for the content of curing agent in composite solid propellant slurry, provide a new method for monitoring the change law of curing agent content during slurry curing, provide a quantitative basis for studying the degree of curing at the propellant and liner interface, and provide data support for solving the problem of solid propellant interface debonding. Attached Figure Description

[0032] Figure 1 This is a diagram of the sampling device in this invention.

[0033] Figure 2 This is a diagram of the infrared spectroscopy multiple internal reflection accessory sample cell pressure adjustment device in this invention.

[0034] Figure 3 This is a partial view of the infrared spectroscopy multiple internal reflection accessory sample cell pressure adjustment device in this invention. Detailed Implementation

[0035] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 As shown in the figure, this application provides a sampling device for composite solid propellant slurry. The sampling device may include: an adjusting handle 1, an upper cover 2, a pressure chamber 3, a slider 4, a storage chamber 5, and a sealing ring 6.

[0037] The adjusting handle 1, upper cover 2, pressure chamber 3, and slider 4 can be a set used to squeeze and discharge material from the storage chamber 5. The pressure chamber 3 can be used to connect the upper cover 2 and the storage chamber 5. One end of the outer circumference of the pressure chamber 3 can be threadedly connected to the large end opening of the upper cover 2, and the other end of the outer circumference of the pressure chamber 3 can be threadedly connected to the large end opening of the storage chamber 5.

[0038] The pressure chamber 3 has an internal cavity for the adjustment handle 1 to move. The adjustment handle 1 may include a handle portion and a moving rod. The handle portion may be located on the side of the upper cover 2 away from the pressure chamber 3. The outer diameter of the handle portion may be larger than the inner diameter of the small end opening of the upper cover 2 (the small end opening of the upper cover 2 is located on the side of the upper cover 2 away from the pressure chamber 3 and is located at the center of the upper cover 2), so that the handle portion is always located outside the pressure chamber 3. The moving rod may be threaded into the small end opening of the upper cover 2 and enter the pressure chamber 3 through the small end opening of the upper cover 2. The inner diameter of the moving rod may be smaller than the inner diameter of the pressure chamber 3, so that the moving rod can move smoothly within the pressure chamber 3.

[0039] The inner cavity of the pressure chamber 3 can communicate with the storage space of the storage chamber 5. The inner diameters of the communicating spaces of the pressure chamber 3 and the storage chamber 5 can be the same. The end of the moving rod of the adjusting handle 1 away from the handle portion can be fixedly connected to the slider 4. The adjusting handle 1 and the slider 4 can be fixed together, for example, by welding. The slider 4 can fit tightly against the inner wall of the pressure chamber 3 or the inner wall of the storage chamber 5. Specifically, when the adjusting handle 1 extends relatively shortly into the pressure chamber 3, the outer periphery of the slider 4 can contact the inner wall of the pressure chamber 3. When the adjusting handle 1 extends relatively shortly into the pressure chamber 3, the outer periphery of the slider 4 can contact the inner wall of the storage chamber 5. To ensure stable material extrusion, a sealing ring 6 can be provided on the slider 4, so that the movement of the slider 4 in the pressure chamber 3 and the storage chamber 5 is sealed by the sealing ring 6. The connection between the pressure chamber 3 and the storage chamber 5 can also be sealed by the sealing ring 6.

[0040] Combination Figure 1 Add propellant slurry to storage chamber 5. After installing the adjusting handle 1, upper cover 2, pressure chamber 3, and slider 4 as shown in the diagram, connect the pressure chamber 3 to storage chamber 5 via threads. Rotating the threads of the adjusting handle 1 and upper cover 2 depresses the slider, discharging the slurry through the outlet of storage chamber 5. The amount of slurry extruded can be quantitatively calculated by the rotation angle of the handle. The calculation formula is as follows:

[0041] in,

[0042] V—Extrusion rate of the slurry fluid.

[0043] θ — the rotation angle of adjustment handle 1.

[0044] P—Adjusting the thread pitch of handle 1 and upper cover 2.

[0045] S — is the cross-sectional area of ​​slider 4.

[0046] Figure 2 and Figure 3This application provides an adjustable pressure device for an infrared spectrometer. The device may include: a handle 11, a screw 12, a top plate 13, a locating pin 14, a set screw 15, a retaining ring 16, a pressure plate 17, a spring 18, a base plate 19, and a pressure plate 20. The handle 11 is connected to the screw 12. The screw 12 can pass through the center hole of the top plate 13 and engage with the retaining ring 16. The top plate 13 can be supported on the base plate 19 by the locating pin 14. The space between the top plate 13 and the base plate 19 can be used to accommodate the retaining ring 16, the pressure plate 17, and the spring 18.

[0047] The base plate 19 is fixed to the infrared multiple internal reflection accessory sample cell using the set screw 15. Rotating the adjusting handle 11 one revolution rotates the screw 12 one revolution, feeding one thread pitch axially, which in turn allows the retaining spring 16 to apply pressure to the pressure plate 17 axially. Adjusting the handle 11 changes the position of the pressure plate 17, causing the spring 18 to deform, thus allowing the pressure plate 20 to apply pressure to the infrared multiple internal reflection accessory sample cell. The magnitude of the pressure can be calculated using the compression amount. The calculation formula is as follows:

[0048] in,

[0049] F—Pressure applied by the pressure device to the sample cell of the infrared multiple internal reflection accessory.

[0050] k—the spring constant of spring 18.

[0051] Δx — Displacement of pressure plate 17

[0052] θ — the rotation angle of the adjustment handle 11.

[0053] P—Thread pitch of screw 12.

[0054] The present invention provides a method for testing the content of curing agent in composite solid propellant slurry, comprising the following steps:

[0055] Step 1: Select a suitable composite solid propellant slurry formulation and determine the curing time and temperature. Specifically, select a propellant slurry with isocyanate as the curing agent.

[0056] Step 2: Under set temperature conditions, Fourier transform infrared spectroscopy was used to test the composite solid propellant slurry with different curing reaction times. Specifically:

[0057] Step 2-1: Using a propellant slurry sampling device, take an appropriate amount of sample and coat the sample cell of the infrared multiple internal reflection accessory.

[0058] Step 2-2: Use a Fourier transform infrared spectrometer, with 16–64 scans and a resolution of 4 cm⁻¹. -1 The wavelength range is 4000cm. -1~650cm -1 An adjustable pressure device is set to pressurize the sample cell to obtain an infrared spectrum, and the infrared spectral data is stored in the form of absorbance.

[0059] Step 3: Using Fourier transform infrared spectroscopy (FTIR) results, establish a model for the change in curing agent content during the curing process of the propellant slurry. Specifically:

[0060] Step 3-1: Process the infrared spectral data. Select one of the following: original spectrum, first derivative spectrum, or second derivative spectrum. Select one of the following smoothing methods: no smoothing, SG smoothing, or Norris smoothing.

[0061] Step 3-2: Establish a quantitative model, using one or more of the following methods: Beer-Lambert law, least squares (CLS), stepwise multiple linear regression, partial least squares (PLS), and principal component regression (PCR).

[0062] Step 3-3: Establish a model for the content of the curing agent in the slurry, and verify the established model.

[0063] Step 4: Calculate the content of residual curing agent in slurries with different curing degrees under the same formulation based on the model. Specifically, obtain the infrared spectrum of the propellant with the same formulation obtained from subsequent tests, and select the target mode in the model through step 3-3 to obtain the content of curing agent in the propellant.

[0064] Example 1

[0065] Hydroxybutadiene propellant was selected for testing. The binder was hydroxyl-terminated polybutadiene, the curing agent was isophorone diisocyanate, the plasticizer was dioctyl sebacate, the curing temperature was 60℃, and the curing time was 8 hours. The specific test methods and procedures are as follows:

[0066] The infrared spectrometer parameters were set to 32 scans and 4 cm⁻¹ resolution. -1 The wavelength range is 4000cm. -1 ~650cm -1 First, a blank background is collected. Then, the propellant slurry is placed in the infrared total reflection sample cell using a sampler. The sample is pressed and covered using the adjustable pressure device of the internal reflection accessory sample cell multiple times. The sample image is then collected to obtain the infrared spectrum of the butyl hydroxyl propellant slurry.

[0067] Samples were taken every hour, and infrared spectra were scanned. The infrared spectral data were processed, using either the original spectrum, the first derivative spectrum, or the second derivative spectrum, and smoothing methods including no smoothing, SG smoothing, or Norris smoothing. A quantitative model was then established using one or more of the following methods: Beer-Lambert law, least squares (CLS), stepwise multiple linear regression, partial least squares (PLS), and principal component regression (PCR). The established model was then validated. The content of the curing agent in the hydroxyl-butyl propellant could be determined by using the infrared spectra of the same propellant obtained from subsequent tests and applying them to the target mode in the model.

[0068] Example 2

[0069] The test used an azide propellant, with 3,3-bis(azidomethyl)oxetane / tetrahydrofuran copolyether as the binder, toluene diisocyanate as the curing agent, and dioctyl sebacate as the plasticizer. The curing temperature was 60℃, and the curing time was 6 hours. The specific test methods and procedures are as follows:

[0070] The infrared spectrometer parameters were set to 32 scans and 4 cm⁻¹ resolution. -1 The wavelength range is 4000cm. -1 ~650cm -1 First, a blank background is collected. Then, the propellant slurry is placed in the infrared total reflection sample cell using a sampler. The sample is pressed and covered using the adjustable pressure device of the internal reflection accessory sample cell multiple times. The sample image is then collected to obtain the infrared spectrum of the azide propellant slurry.

[0071] Samples were taken every hour, and infrared spectra were scanned. The infrared spectral data were processed, using either the original spectrum, the first derivative spectrum, or the second derivative spectrum, and smoothing methods including no smoothing, SG smoothing, or Norris smoothing. A quantitative model was then established, employing one or more of the following methods: Beer-Lambert law, least squares (CLS), stepwise multiple linear regression, partial least squares (PLS), and principal component regression (PCR). The established model was then validated. By applying the infrared spectra of the same propellant obtained from subsequent tests to the target mode in the model, the content of the curing agent in the azide propellant could be determined.

[0072] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. A method for testing the content of curing agent in composite solid propellant slurry, characterized in that, include: Step 1: Select the composite solid propellant slurry to be tested and determine the curing temperature; Step 2, under the set temperature condition, the composite solid propellant slurry with different curing reaction time is tested by Fourier infrared spectrum; including: taking appropriate sample by sampling device, and coating the sample in the infrared multiple internal reflection accessory sample cell; setting the scanning times of Fourier infrared spectrometer to 16-64 times, setting the resolution to 4 cm -1 , the wavelength range is 4000 cm -1 ~ 650 cm -1 , and the sample cell is pressurized by an adjustable pressure device to obtain an infrared spectrum, and the infrared spectrum data is stored in the form of absorbance; Step 3: Using Fourier transform infrared spectroscopy to test the results, establish a model for the change in curing agent content during the curing process of the propellant slurry; Step 4: Calculate the curing agent content corresponding to the curing reaction time of the same propellant slurry without Fourier transform infrared spectroscopy test based on the model; The sampling device includes: a first adjusting handle (1), an upper cover (2), a pressure chamber (3), a slider (4), and a storage chamber (5); wherein, the pressure chamber (3) is connected between the upper cover (2) and the storage chamber (5); the inner cavity of the pressure chamber (3) is in communication with the storage space of the storage chamber (5), and the inner diameter of the space in which the pressure chamber (3) and the storage chamber (5) are in communication is consistent; the first adjusting handle (1) extends into the pressure chamber (3) through the inlet of the upper cover (2); a slider (4) is provided at one end of the first adjusting handle (1) located in the pressure chamber (3), and the slider (4) is in close contact with the inner wall of the pressure chamber (3) or the storage chamber (5); The first adjusting handle (1) is threaded into the inlet; the sliding block (4) is pressed down by rotating the threads of the first adjusting handle (1) and the upper cover (2), and the slurry is discharged through the outlet of the storage chamber (5). The amount of slurry extruded can be quantitatively calculated by rotating the first adjusting handle (1); the material extruded by the sampling device meets the following requirements: ,in, This refers to the extrusion volume of the slurry fluid. The rotation angle of the first adjusting handle (1), The thread pitch of the first adjusting handle (1) is... Let be the cross-sectional area of ​​slider (4); An adjustable pressure device includes: a second adjusting handle (11), a screw (12), a top plate (13), a positioning pin (14), a set screw (15), a snap ring (16), a pressure plate (17), a spring (18), a bottom plate (19), and a pressure plate (20); wherein, the second adjusting handle (11) is connected to the screw (12); the screw (12) passes through the center hole of the top plate (13) and cooperates with the snap ring (16); the top plate (13) is supported on the bottom plate (19) by the positioning pin (14), and the space between the top plate (13) and the bottom plate (19) is used to accommodate the pressure plate (17) and the spring (18); the snap ring (16) is used to apply pressure to the pressure plate (17) to cause the spring (18) to deform; the set screw (15) fixes the bottom plate (19) to the infrared multiple internal reflection accessory sample cell; the pressure plate (20) is used to apply pressure to the infrared multiple internal reflection accessory sample cell under the action of the spring (18); The position of the pressure plate (17) is changed by the second adjusting handle (11), which causes the spring (18) to deform, so that the pressure plate (20) applies pressure to the infrared multiple internal reflection accessory sample cell. The pressure calculation formula is: ,in, The adjustable pressure device applies pressure to the sample cell of the infrared multiple internal reflection accessory. The spring constant of spring (18) is... The rotation angle of the second adjusting handle (11), The thread pitch of the screw (12) is denoted as .

2. The method according to claim 1, characterized in that, Step 3 specifically includes: processing the infrared spectral data, selecting one of the original spectrum, the first derivative spectrum, or the second derivative spectrum, and selecting one of the smoothing methods: no smoothing, SG smoothing, or Norris smoothing; establishing a quantitative model, using one or more of the following methods: Lambert-Beer law, least squares method, stepwise multiple linear regression, partial least squares method, and principal component regression; and establishing a model for the content of the slurry curing agent.

3. The test method according to claim 1, characterized in that, The upper cover (2) is used to seal the opening of the pressurized chamber (3) away from the storage chamber (5).

4. The test method according to claim 1, characterized in that, The first adjustment handle (1) includes a handle part and a moving rod; the handle part is located on the side of the upper cover (2) away from the pressure chamber (3), and the outer diameter of the handle part is larger than the inner diameter of the inlet; the moving rod is engaged with the inlet, and the inner diameter of the moving rod is smaller than the inner diameter of the pressure chamber (3).

5. The test method according to claim 1, characterized in that, A sealing ring (6) is provided on the slider (4). The slider (4) is sealed to the pressure chamber (3) by the sealing ring (6), and the slider (4) is sealed to the storage chamber (5) by the sealing ring (6).

6. The test method according to claim 1, characterized in that, The connection between the pressurization chamber (3) and the storage chamber (5) is sealed by a sealing ring (6).

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