A device and method for collecting gas released during solid propellant aging

Abstract

The present invention provides a device and method for collecting gases released during the aging process of solid propellants. A device for collecting gases released during the aging process of solid propellants is characterized in that it includes a shell, a sample bag, a pressure gauge, a pressure regulating unit, a shell sealing unit, an air intake unit, and air inlet and outlet ports. Gas is extracted from the sample bag by the sampling unit, injected into the cavity, and detected by infrared spectroscopy. Compared with the prior art, the collection device in the present invention has the characteristics of novel design, simple structure, easy operation, easy cleaning, and can be used with an infrared spectrometer to quickly detect gas components. The test data obtained has a small error, enriches the means of characterizing the propellant aging process, and is helpful for studying the propellant aging mechanism and estimating the storage life.

Description

Technical Field

[0001] The invention belongs to the technical field of composite solid propellant performance testing, and in particular relates to a device for collecting gas generated during the aging process of a composite solid propellant and a use method thereof. Background Art

[0002] With the widespread application of composite solid propellants in rocket engines and missile weapons and equipment, people pay more and more attention to their storage safety. Composite solid propellants are mainly composed of adhesives, oxidants, curing agents, plasticizers, burning rate additives and other functional additives, and have the characteristics of multiple components and complex ingredients. During the storage process, composite solid propellants are affected by ambient temperature, humidity, radiation, light, heat, oxygen and other factors, and their components undergo thermal decomposition and migration, which changes the components and structure of the propellant, and the performance of the propellant also changes accordingly. Chemical reactions and thermal effects of some components inside the solid propellant will release a variety of gas products. In addition to accelerating the chemical process, the gas of the aging decomposition reaction may also destroy the structural integrity of the grain. When the rate at which the gas diffuses through the propellant is slower than the gas release, the gas pressure built up inside the grain may exceed the strength of the propellant and cause internal cracks.

[0003] The physical properties of composite solid propellants depend on their corresponding chemical composition and structure. Qualitative and quantitative analysis of the gas products during the aging process can help identify subtle changes in the chemical composition and chemical structure of the propellant during aging, which is of great significance for the estimation of the storage life of the propellant.

[0004] At present, the research on propellant aging mainly focuses on parameters such as mechanical properties, degree of gelation, and changes in chemical composition, while there are relatively few studies on gas products. This is mainly due to the difficulty in collecting gas products on the one hand and the difficulty in quantitative analysis of gas products on the other. However, during the actual storage of propellants, not every parameter changes very obviously, and some parameters change very little. Therefore, conducting research on propellant gas products can enrich the means of propellant aging characterization, which is helpful for the study of propellant aging mechanism and the estimation of storage life. Summary of the invention

[0005] In order to overcome the deficiencies in the prior art, the inventors have conducted intensive research and provided a device for collecting gases released during the aging process of solid propellants. The device can be used to collect gases generated during the aging of propellants with different characteristic formulas and can be directly used for infrared spectroscopy detection. The test process is simple and convenient with high accuracy, which can enrich the means of propellant aging characterization and contribute to the study of the propellant aging mechanism and the estimation of the storage life.

[0006] The technical solution provided by the present invention is as follows: a device for collecting gas released during the aging process of solid propellant, comprising a shell, a sample bag, a pressure gauge, a pressure test adjustment unit, a shell sealing unit, an air intake unit, and an air intake and exhaust port;

[0007] The shell forms a sealed cavity through the shell sealing unit, and three air ports are arranged on the shell, one of which is used as an air inlet and an air outlet, one is installed with an air inlet unit, and one is installed with a pressure test adjustment unit;

[0008] The sample bag is used to contain solid propellant, and the sample bag valve is connected to the air intake unit, and the gas released during the aging process is injected into the sealed cavity through the air intake unit under negative pressure;

[0009] The pressure test adjustment unit is used to adjust the vacuum degree in the sealed cavity to meet the preset requirements, and the air inlet and outlet are used to ensure the safety of the sealed cavity.

[0010] Preferably, the air intake unit comprises three air valves, a syringe and a needle;

[0011] The gas port on the shell is connected to two gas valves through a gas pipeline and then a needle is installed. The two gas valves are connected to a third gas valve through a pipeline, and the third gas valve is connected to the syringe; the needle is used to connect to the sample bag valve; the syringe is used to extract aging gas from the sample bag and inject gas into the sealed cavity.

[0012] Preferably, the syringe has a volume of 0 to 50 mL and is replaceable with a scale; the three gas valves are ball valves made of stainless steel; the gas pipeline is a polytetrafluoroethylene tube, and the needle is detachable and replaceable.

[0013] Preferably, the shell sealing unit is respectively located on the left and right sides of the shell, and the left part, starting from the left end face of the shell, includes the following parts in sequence: a sealing gasket, a splint, a sealing gasket, a window piece, a sealing gasket, and a splint, and the above parts are fitted to the shell end face by a plurality of bolts arranged in a ring, and the other parts except the leftmost sealing gasket are tightly fitted by a plurality of screws arranged in a ring; the right part, starting from the right end face of the shell, includes a sealing gasket, a window piece, a sealing gasket, and a splint in sequence, and is fitted to the shell end face by a plurality of bolts arranged in a ring, and the right end face of the shell is tightly fitted to the sealing gasket, the window piece, the sealing gasket, and the splint by a plurality of screws arranged in a ring.

[0014] Preferably, the housing sealing unit is detachable and the housing is washable.

[0015] Preferably, the sealing gaskets on both sides of the window have stepped holes in their centers, forming annular grooves to fix the window.

[0016] Preferably, the window is made of potassium bromide.

[0017] Preferably, the pressure test adjustment unit includes a gas valve switch, a gas pipeline and a vacuum pump; the gas valve switch is a ball valve made of stainless steel; the gas pipeline is a polytetrafluoroethylene tube, and the vacuum pump is equipped with a pressure gauge for adjusting the cavity pressure.

[0018] Preferably, the sample bag is made of Teflon.

[0019] A method for performing aging analysis on a propellant aging gas collection device comprises the following steps:

[0020] Place the propellant in a sample bag, seal it, and then draw a vacuum or flush it with nitrogen;

[0021] Close the air inlet unit and the air inlet and outlet, and open the pressure test adjustment unit to make the sealed cavity reach the preset vacuum degree and ensure the pressure in the sealed cavity is stable;

[0022] Scan the sealed cavity with an infrared spectrometer to obtain a standard spectrum;

[0023] Open the air valve connected to the needle and syringe of the air inlet unit, insert the needle into the valve of the sample bag, extract a certain volume of aging gas, close the air valve connected to the needle, open the air valve connected to the gas port of the shell, and inject gas using a syringe;

[0024] The sealed cavity is scanned by an infrared spectrometer, and the obtained infrared spectrum is compared with the above-mentioned standard spectrum to determine the test result.

[0025] Preferably, in view of the low concentration of the extracted gas and the weak absorption intensity of the infrared spectrum, the three gas valves of the air intake unit are adjusted on and off, and the injector extracts the gas samples multiple times and injects them into the sealed cavity.

[0026] Preferably, the concentration of the gas sample is calculated using a standard curve method.

[0027] The beneficial effects of the present invention compared with the prior art are as follows:

[0028] The device for collecting gas released during the aging process of solid propellants and the method for using the device provided by the present invention can be used for collecting and detecting gas released during the aging process of various solid propellants. Compared with the prior art, the device in the present invention has the characteristics of novel design, simple structure, and easy operation. It can be used in conjunction with an infrared spectrometer to quickly monitor gas composition, and the test data obtained by the test has a small error. Therefore, the invention provides an effective and reliable collection device and method for detecting gas released during the aging process of propellants, and provides strong support for the study of the aging mechanism of propellants. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of a device for collecting gases released during the aging process of solid propellant;

[0030] Figure 2 It is a schematic diagram of the structure of the shell;

[0031] Figure 3 It is a structural schematic diagram of the left end surface of the shell;

[0032] Figure 4 It is a schematic diagram of the structure of the right end face of the shell;

[0033] Figure 5 is a schematic structural diagram of a sealing gasket (27);

[0034] Figure 6 It is a structural schematic diagram of a splint (25);

[0035] Figure 7 is a schematic structural diagram of a sealing gasket (21);

[0036] Figure 8 It is a structural schematic diagram of a clamping plate (26).

[0037] Fig. 9 This is the infrared spectrum of Example 1

[0038] Fig.10 This is the infrared spectrum of Example 2 DETAILED DESCRIPTION

[0039] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0040] According to a first aspect of the present invention, there is provided a device for collecting gas released during the aging process of solid propellant, such as Figure 1 As shown, it includes a shell, a sample bag, a pressure gauge, a pressure regulating unit, a shell sealing unit, an air intake unit, and an air inlet and outlet; wherein the material of the sample bag is preferably Teflon.

[0041] like Figure 2 As shown, the housing 1 includes three gas ports 3 / 12 / 19. Specifically, the gas port 3 is connected to the gas valve 2 and is connected to the vacuum pump 7 through the gas pipeline 6; the gas port 12 is used for deflation or inflation; the gas port 19 is connected to the gas valve 16, one end of which is connected to the syringe 14 through the gas valve 15, and the other end is connected to the needle 17 through the gas valve 18. The gas valve switch 2 is a ball valve made of stainless steel; the gas pipeline is a polytetrafluoroethylene tube, and the vacuum pump 7 is equipped with a high-precision pressure gauge for adjusting the cavity pressure.

[0042] The syringe 14 has a volume of 0 to 50 mL and is replaceable with a scale, and is used to inject and extract gas from the cavity; the gas valve 15 / 16 / 18 is a ball valve made of stainless steel; the gas pipeline 6 is a polytetrafluoroethylene tube, and the needle 17 is detachable and replaceable.

[0043] like Figure 3 As shown, on the left end face of the shell, 6 threaded holes are arranged around the center; Figure 5 As shown, the sealing gasket 27 is surrounded by 6 threaded holes, and the threaded holes correspond to the threaded holes on the left end surface of the shell one by one; Figure 6 As shown, the clamping plate 25 has 6 threaded holes arranged near the center and away from the center. Specifically, the threaded holes near the center are countersunk holes, and the threaded holes away from the center correspond to the threaded holes of the sealing gasket 27 one by one; Figure 7 As described above, the centers of the sealing gaskets 21 and 22 are stepped holes, forming an annular groove to fix the window sheet 24; Figure 8 As shown, the clamping plate 26 is an annular thin plate with 6 threaded holes arranged near the center and 6 threaded holes arranged away from the center. The above components are fastened by bolts and screws arranged in a circle to ensure that the components fit tightly.

[0044] like Figure 4 As shown, the right end face of the shell has 6 threaded holes arranged in a circle near the center and 6 threaded holes arranged in a circle away from the center; the sealing gaskets 11 / 12 are the same as the sealing gaskets 21 and 22, forming an annular groove to fix the window sheet 24; the clamping plate 5 is the same as the clamping plate 26, which is an annular thin plate, has 6 threaded holes arranged in a circle near the center and 6 threaded holes arranged in a circle away from the center, and the above-mentioned components are ensured to fit tightly through the bolts and screws arranged in the circle.

[0045] Specifically, the housing sealing unit is located on the left and right sides of the housing, respectively. The left side, starting from the left end face of the housing, is provided with a sealing gasket 27, a clamping plate 25, a sealing gasket 21, a window sheet 24, a sealing gasket 22, and a clamping plate 26 in sequence. The clamping plate 25, the sealing gasket 21, the window sheet 24, the sealing gasket 22, and the clamping plate 26 are tightly fitted by a ring cloth 6 screws 23. The right side, starting from the right end face of the housing, is provided with a sealing gasket 11, a window sheet 8, a sealing gasket 10, and a clamping plate 5 in sequence. The sealing gasket 11, the window sheet 8, the sealing gasket 10, and the clamping plate 5 are tightly fitted by a ring cloth 6 screws 9 to fit the right end face of the housing with the sealing gasket 11, the window sheet 8, the sealing gasket 10, and the clamping plate 5; the left end face has a large opening, the diameter of which is the same as the inner diameter of the cavity, so that the inner cavity can be easily cleaned after disassembly, and the right end face has a small opening. Therefore, the right end surface is equivalent to the clamping plate, and compared with the right side, the left side is added with a gasket 27 and a clamping plate 25. The material of the window sheet 8 / 24 is potassium bromide.

[0046] The method for using the propellant aging gas collection device according to the second aspect is as follows:

[0047] Place the propellant in a sample bag, seal it, and then draw a vacuum or flush it with nitrogen. After aging, the gas is injected into the gas collection device. Check the air tightness of the device before testing. Specifically, close the air inlet unit and the air inlet and outlet valves before injection, open the air valve of the pressure test adjustment unit, turn on the vacuum pump, let the pressure gauge reach the specified reading, close the air valve of the pressure adjustment unit and the vacuum pump, observe the pressure gauge reading, if the reading changes, it indicates a leak, check and tighten all connections, readjust until the pressure stabilizes, scan the background, open the air valve switch connected to the needle and the syringe, insert the needle into the sampling bag valve, extract a certain volume of gas, close the air valve switch connected to the needle, open the shell air port connection switch, inject gas, perform infrared spectroscopy scanning after injection, and compare the infrared spectrum with the standard spectrum to determine the test results. Compare the test results of propellants at different aging times, predict the possible aging reaction process of the propellant based on the gas generation, and judge the aging speed based on the changes in different spectral intensities.

[0048] Example

[0049] Example 1: Collection and testing of a composite solid propellant of a certain formula after aging for a certain period of time

[0050] Put the propellant in the sample bag, seal it and draw a vacuum, and age it for a certain period of time. Specifically, before injection, close the air inlet unit and the air inlet and exhaust valves, open the air valve of the pressure test adjustment unit, turn on the vacuum pump, let the pressure gauge reach the specified reading, close the air valve of the pressure adjustment unit and the vacuum pump, observe the pressure gauge reading, if the reading changes, it indicates a leak, check and tighten all connections, readjust until the pressure stabilizes, use infrared spectroscopy to scan the background, open the air valve switch connected to the needle and syringe, insert the needle into the sampling bag valve, extract a certain volume of gas, close the air valve switch connected to the needle, open the shell air port connection switch, inject gas, perform infrared spectroscopy scanning after injection, and the test results are as follows Fig. 9 .

[0051] Example 2: Collection and testing of a composite solid propellant of a certain formula after aging for a certain period of time

[0052] Put the propellant in the sample bag, seal it and draw a vacuum, and age it for a certain period of time. Specifically, before injection, close the air inlet unit and the air inlet and exhaust valves, open the air valve of the pressure test adjustment unit, turn on the vacuum pump, let the pressure gauge reach the specified reading, close the air valve of the pressure adjustment unit and the vacuum pump, observe the pressure gauge reading, if the reading changes, it indicates a leak, check and tighten all connections, readjust until the pressure stabilizes, use infrared spectroscopy to scan the background, open the air valve switch connected to the needle and syringe, insert the needle into the sampling bag valve, extract a certain volume of gas, close the air valve switch connected to the needle, open the shell air port connection switch, inject gas, perform infrared spectroscopy scanning after injection, and the test results are as follows Fig.10 .

[0053] The detection of released gas during the solid propellant aging process proposed by the present invention can meet the needs of various types of propellant sample detection, with accurate test data and high test efficiency.

[0054] The present invention has been described in detail above in conjunction with specific implementation methods and examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present invention and its implementation methods, which all fall within the scope of the present invention. The protection scope of the present invention shall be subject to the attached claims.

[0055] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A device for collecting gas released during the aging process of solid propellant, characterized in that: It includes a shell, a sample bag, a pressure gauge, a pressure test adjustment unit, a shell sealing unit, an air intake unit, and an air inlet and outlet; The shell forms a sealed cavity through the shell sealing unit, and three air ports are arranged on the shell, one of which is used as an air inlet and an air outlet, one is installed with an air inlet unit, and one is installed with a pressure test adjustment unit; The sample bag is used to contain solid propellant, and the sample bag valve is connected to the air intake unit, and the gas released during the aging process is injected into the sealed cavity through the air intake unit under negative pressure; The pressure test adjustment unit is used to adjust the vacuum degree in the sealed cavity to meet the preset requirements, and the air inlet and outlet are used to ensure the safety of the sealed cavity; The air intake unit includes three air valves, a syringe and a needle; The gas port on the shell is connected to two gas valves through a gas pipeline and then a needle is installed. The two gas valves are connected to a third gas valve through a pipeline, and the third gas valve is connected to the syringe; the needle is used to connect to the valve of the sample bag; the syringe is used to extract aging gas from the sample bag and inject gas into the sealed cavity; The pressure test adjustment unit includes a gas valve switch, a gas pipeline and a vacuum pump; the gas valve switch is a ball valve made of stainless steel; the gas pipeline is a polytetrafluoroethylene tube, and the vacuum pump is equipped with a pressure gauge for adjusting the cavity pressure; The shell sealing unit is respectively located on the left and right sides of the shell. The left part, starting from the left end face of the shell, includes the following parts in sequence: a sealing gasket, a splint, a sealing gasket, a window sheet, a sealing gasket, and a splint. The above parts are fitted with the shell end face by a plurality of bolts arranged in a ring, and the other parts except the leftmost sealing gasket are tightly fitted by a plurality of screws arranged in a ring; the right part, starting from the right end face of the shell, includes a sealing gasket, a window sheet, a sealing gasket, and a splint in sequence. The sealing gasket is fitted with the shell end face by a plurality of bolts arranged in a ring, and the right end face of the shell is tightly fitted with the sealing gasket, the window sheet, the sealing gasket, and the splint by a plurality of screws arranged in a ring; the left end face of the shell has a large opening, and the diameter is the same as the inner diameter of the cavity, so that the inner cavity can be easily cleaned after disassembly, and the right end face has a small opening; Aging analysis was performed by: Place the propellant in a sample bag, seal it, and then draw a vacuum or flush it with nitrogen; Close the air inlet unit and the air inlet and outlet, and open the pressure test adjustment unit to make the sealed cavity reach the preset vacuum degree and ensure the pressure in the sealed cavity is stable; Scan the sealed cavity using an infrared spectrometer to obtain a standard spectrum; Open the air valve connected to the needle and syringe of the air inlet unit, insert the needle into the valve of the sample bag, extract a certain volume of aging gas, close the air valve connected to the needle, open the air valve connected to the gas port of the shell, and inject gas using a syringe; Scan the sealed cavity using an infrared spectrometer, and compare the obtained infrared spectrum with the above-mentioned standard spectrum to determine the test result; The syringe has a volume of 0 to 50 mL and is replaceable with scales; the three gas valves are ball valves made of stainless steel; the gas pipeline is a polytetrafluoroethylene tube, and the needle is detachable and replaceable.

2. The gas collection device according to claim 1, characterized in that: The housing sealing unit is detachable and the housing is washable.

3. The gas collection device according to claim 2, characterized in that: The material of the window is potassium bromide.

4. The gas collection device according to claim 2, characterized in that: The sealing gaskets on both sides of the window have step holes in their centers, forming an annular groove to fix the window.

5. The gas collection device according to claim 1, characterized in that: The sample bag is made of Teflon.

6. The gas collection device according to claim 1, characterized in that: In view of the low concentration of the extracted gas and the weak absorption intensity of the infrared spectrum, the three gas valves of the air inlet unit are opened and closed, and the injector draws gas samples multiple times and injects them into the sealed cavity.

7. The gas collection device according to claim 1, characterized in that: The concentration of gas samples was calculated using the standard curve method.

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