Cuboid propellant powder with prefabricated notch grooves

Abstract

The appearance of the cuboid propellant powder is a cuboid, and the front end face and the rear end face of the cuboid propellant powder are square. At least one prefabricated notch groove is formed in the cuboid prefabricated notch groove propellant powder, the prefabricated notch grooves are parallel to the top face of the cuboid prefabricated notch groove propellant powder, the prefabricated notch grooves penetrate through the front end face and the rear end face of the cuboid prefabricated notch groove propellant powder, and the prefabricated notch grooves are evenly distributed in a square. According to the cuboid propellant powder with the prefabricated notch grooves, the multiple notch grooves are prefabricated in the cuboid powder column, so that the adaptability of the appearance of the propellant powder and the internal notch groove structure is improved, and the problem that the cuboid propellant powder is difficult to achieve gradual combustion is solved; by adjusting and controlling the size of the prefabricated notch grooves and the arrangement mode of the prefabricated notch grooves, the combustion gradual increase of the cuboid propellant powder is improved; high loading density can be achieved by taking a proper length-width ratio.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of propellant, in particular to a cuboid prefabricated grooving propellant. BACKGROUND

[0002] The core task of propellant charge research is to improve the propulsive force of the projectile, and there are two technical approaches to complete this core task, namely, improving the total energy of the propellant charge and improving the energy utilization efficiency. Optimizing the combustion progression of the propellant can effectively improve the energy utilization efficiency of the barrel weapon. Developing high-loading-density charges, increasing the single-shot charge amount, selecting high-energy formulations, and improving the propellant force can improve the total charge energy to a certain extent.

[0003] CN202210105813.1 discloses a center-holed sequential split propellant, which has a good combustion progression due to the continuous increase in the combustion area caused by the groove structure and the expansion of the center hole. The designed center-holed sequential split propellant has square grooves distributed circumferentially in the cylindrical propellant. According to the geometric combustion law of the propellant, as the combustion process proceeds, the square grooves gradually expand and will connect with the adjacent grooves and the circular outer edge, so there must be a split surface reduction combustion stage after splitting, that is, the adaptability of the propellant shape and the internal groove structure needs to be further optimized.

[0004] Related research at home and abroad shows that the cuboid shape is beneficial to reducing the gap between the grains, and its bulk density is greater than that of the cylindrical propellant under the same formulation, which can improve the loading density of the propellant. However, the existing cuboid propellants, such as the cuboid four-hole propellant, usually exhibit a surface reduction combustion state in the actual combustion process due to the relatively small number of internal holes and large size deviation. UTILITY MODEL CONTENT

[0005] In view of the problem that the existing cuboid propellant is difficult to achieve gradual combustion, the utility model aims to provide a cuboid prefabricated grooving propellant, which optimizes the adaptability of the shape and internal groove structure of the existing center-holed sequential split propellant, further optimizes the combustion performance, and achieves a high loading density.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0007] A cuboid prefabricated grooving propellant has a cuboid shape, with square front and rear end faces, and the side length of the square face can be adjusted arbitrarily to adapt to different caliber platforms. The cuboid prefabricated grooving propellant has at least one prefabricated groove inside, which is parallel to the top face of the cuboid prefabricated grooving propellant, and the prefabricated groove penetrates the front and rear end faces of the cuboid prefabricated grooving propellant.

[0008] Further, when the number of prefabricated grooves is greater than or equal to 2, all prefabricated grooves are uniformly distributed from top to bottom, the distance between two adjacent prefabricated grooves, the distance between the uppermost prefabricated groove and the top surface of the cuboid prefabricated groove propellant, and the distance between the lowermost prefabricated groove and the bottom surface of the cuboid prefabricated groove propellant are all equal.

[0009] Further, the prefabricated grooves are centrally distributed in the horizontal direction, that is, the distance from the left end point of the groove to the left edge of the propellant is equal to the distance from the right end point of the groove to the right edge of the propellant. The essence of this equal distance design is to require the arc thickness of the two ends to be equal, which is beneficial to the simultaneous burning of each part of the propellant.

[0010] Further, the thickness of the prefabricated groove is 0.15mm-0.25mm. The smaller the groove thickness, the more difficult the process is to implement. If the groove thickness is too large, the total energy loss will increase, and the end sealing difficulty will also increase.

[0011] Further, the width of the prefabricated groove accounts for 30%-70% of the width of the cuboid prefabricated groove propellant. As an important parameter for adjusting the energy release law, the increase of the groove width increases the adjustment range of the energy release law. If the groove width is too long, it will affect the mechanical strength of the grain, and the control of the width accounts for 30%-70% of the length of the propellant.

[0012] Further, the length of the cuboid prefabricated groove propellant is equal to its width, or the length of the cuboid prefabricated groove propellant is an integer multiple of its width, which is beneficial to reducing the gap between the grains and improving the loading density.

[0013] Compared with the prior art, the cuboid prefabricated groove propellant has the following advantages:

[0014] (1) During the combustion process of the cuboid prefabricated groove propellant, the groove is opened and gradually expanded from a closed state, and the combustion surface area continuously increases, so that the actual combustion process of the cuboid propellant has a certain gradual increase.

[0015] (2) The square groove is prefabricated in the cuboid propellant, which optimizes the adaptability of the propellant shape and the internal groove structure. The groove structure does not intersect during the expansion process, avoids the appearance of remaining parts with strong surface reduction such as fan and triangle after the expansion of the groove, and the groove can be continuously expanded in theory until the end of combustion, so that the combustion split point is delayed.

[0016] (3) The front and rear end surfaces of the cuboid prefabricated groove propellant are square. When the appropriate length-width ratio is taken, the single propellant grain is approximately cuboid or other shapes that are convenient to splice, reducing the gap between the charges and obtaining a higher loading density.

[0017] (4) The cuboid pre-grooved propellant improves energy utilization efficiency by enhancing combustion gradual increase and increases the total energy of the propellant charge by increasing the packing density, thereby achieving the simultaneous effect of the two technical approaches to improve the propellant charge's propulsive force on the projectile.

[0018] The cuboid preformed grooved propellant of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 A three-dimensional structural diagram of a cuboid prefabricated grooved propellant.

[0020] Figure 2 A schematic diagram of the front end of a cuboid prefabricated grooved propellant.

[0021] Figure 3 A schematic diagram of the combustion process of a pre-grooved cuboid propellant.

[0022] Figure 4 The LB curves before and after sealing the cuboid pre-grooved propellant in Example 2;

[0023] Figure 5 The LB curves before and after sealing the cuboid pre-grooved propellant in Example 3 are shown.

[0024] Figure 6 These are the combustion LB curves of cuboid four-hole propellants and spherical flat propellants in the existing technology.

[0025] Among them, 1-pre-made groove. Detailed Implementation

[0026] Example 1

[0027] like Figure 1 , Figure 2 As shown, a cuboid pre-grooved propellant has a cuboid shape with a square front and rear face. The cuboid pre-grooved propellant has three pre-grooves 1 inside, which are parallel to the top surface of the cuboid pre-grooved propellant and penetrate the front and rear faces of the cuboid pre-grooved propellant.

[0028] Three pre-formed grooves 1 are evenly distributed from top to bottom. The distance between any two adjacent pre-formed grooves 1, the distance between the topmost pre-formed groove 1 and the top surface of the cuboid pre-formed groove propellant, and the distance between the bottommost pre-formed groove 1 and the bottom surface of the cuboid pre-formed groove propellant are all equal. The pre-formed grooves 1 are centrally distributed in the horizontal direction, that is, the distance from the left end point of the groove to the left edge of the propellant is equal to the distance from the right end point of the groove to the right edge of the propellant.

[0029] The thickness of the prefabricated grooved 1 is 0.2 mm. The width of the prefabricated grooved 1 accounts for 50% of the width of the cuboid prefabricated grooved propellant. In other beneficial variant embodiments, the thickness of the prefabricated grooved 1 can be designed to be 0.15-0.25 mm according to actual needs. The width of the prefabricated grooved 1 can be designed to be 30%-70% of the width of the cuboid prefabricated grooved propellant.

[0030] The length of the cuboid prefabricated grooved propellant is equal to the width of the cuboid prefabricated grooved propellant, that is, the length-width ratio is 1:1 when cutting the propellant.

[0031] The combustion process of the cuboid prefabricated grooved propellant is shown in Figure 3 , the grooves are opened and gradually expanded from the closed state, and the theoretical combustion surface area continues to increase. Compared with the center-opening cylindrical propellant, the groove structure does not intersect during the expansion process, and the groove can continue to expand until the end of combustion. Therefore, the design of the cuboid prefabricated grooved propellant can not only make the cuboid propellant gradually increase in combustion, but also optimize the adaptability of the shape of the propellant and the internal groove structure.

[0032] The preparation method of the cuboid prefabricated grooved propellant can adopt the common solvent method or semi-solvent method process in the field of propellants, and generally goes through typical processes such as gelation, molding, cutting, drying, and post-processing in the field of propellants. After molding, the groove end face can be sealed by solvent dissolution, coating, and patching.

[0033] The implementation method of the groove structure can refer to patent CN202210105813.1, which also includes a mold body, a needle holder, and a plurality of sheet needles. The difference is that the sheet needles of CN202210105813.1 are uniformly distributed in the circumferential direction in the cylinder, while the sheet needles of the cuboid prefabricated grooved propellant are distributed in the radial direction in parallel. The mold body, the mold needle, and the needle holder can be separated from each other, and adjusting the structure and size of the mold needle can adapt to the preparation needs of propellants with different structure parameters, and facilitate disassembly, cleaning, and replacement.

[0034] Example 2

[0035] Compared with Example 1, the difference is that the square side length of the front end face of the cuboid prefabricated grooved propellant is 2.2 mm x 2.2 mm. One groove is prefabricated. The groove length accounts for 70% of the square side length.

[0036] Also prepared by semi-solvent process, and the end face is sealed by solvent dissolution after molding. The length-width ratio of the cut propellant is 1:1. The closed bomb test is used to verify the combustion performance before and after sealing, and the L-B curve shown in Figure 4 is obtained. Figure 4It can be seen that the first half of the cuboid pre-grooved propellant with one groove structure exhibits uniform combustion, while the second half exhibits reduced-surface combustion. This is because the number of grooves is small, and the arc thickness in the direction perpendicular to the grooves is relatively small. Under this propellant type, the propellant cannot burn completely in all directions simultaneously. To further optimize the combustion performance, it is necessary to increase the number of grooves.

[0037] Example 3

[0038] Compared to Example 1, the difference lies in the following: the square side length of the pre-grooved propellant front end face is 2.5mm × 2.5mm. Two grooves are pre-fabricated. The groove length accounts for 50% of the square side length. The aspect ratio of the propellant is 1:1.

[0039] The same semi-solvent method was used for preparation. The prepared propellant had a square cross-section and uniformly distributed grooves, meeting the design expectations, indicating that the process and mold design can meet the requirements for preparing cuboid pre-grooved propellants. After molding, the ends were dissolved and sealed with ethyl acetate. Its combustion performance was verified using a closed-circuit test. Figure 5 The LB curve shown. (From...) Figure 5 It can be seen that the designed and prepared cuboid pre-grooved propellant with two groove structures has a certain degree of combustion escalation, and the process of the grooves going from closed to open after end sealing is added, so the combustion escalation is more significant.

[0040] Figure 6 Comparing the combustion LB curves of the rectangular four-hole propellant and the spherical flat propellant shown in the existing technology (Xu Zhengguang, Liang Hao, Ding Yajun, et al. Calculation of shape function and combustion performance of four-hole rectangular propellant [J]. Energetic Materials, 2020, 28(6):491-497.), it can be seen that the actual combustion law of the rectangular four-hole propellant, which has the same rectangular appearance, exhibits a decreasing surface area combustion characteristic. The experiment shows that by pre-fabricating a grooved structure in the rectangular matrix propellant, the gradual opening and expansion of the grooved structure leads to a continuous increase in the burning surface, which can realize the combustion gradual increase characteristic of the actual combustion process of the rectangular propellant, achieving the design expectation.

[0041] Example 4

[0042] Compared to Example 1, the difference lies in the fact that the square side length of the front end face of the cuboid pre-grooved propellant is 2mm × 2mm. Two grooves are pre-formed. The groove length accounts for 30% of the side length of the square.

[0043] The drug is prepared using a semi-solvent method, and after molding, the ends are sealed with solvent. The aspect ratio of the cut drug is 1:1.

[0044] The propellant generally needs to be treated with "gloss" before loading, and graphite and other gloss agents are attached to the surface of the propellant grains to improve the loading density by improving the flowability of the grains. The test results show that the bulk density of the cuboid prefabricated grooved propellant prepared in Example 3 reaches 0.98 g·cm -3 , which is higher than the bulk density of the cubic four-hole propellant (0.96 g·cm -3 ) and the cylindrical four-hole propellant (0.94 g·cm -3 ) designed in EP2756 259B1, verifying that the cuboid prefabricated grooved propellant is beneficial to improve the loading density due to the small gap between the grains and the absence of internal holes in the propellant column, and can achieve the design expectation.

[0045] The above-described embodiments are merely preferred embodiments of the present application and are not intended to limit the scope of the present application. It should not be understood as limiting the present application, and various modifications and improvements to the technical solutions of the present application made by those of ordinary skill in the art without departing from the design spirit of the present application shall fall within the protection scope defined by the claims of the present application.

Claims

1. A cuboid preformed grooved propellant, characterized in that: The shape is cuboid, the front end surface and the rear end surface are square; the interior of the cuboid prefabricated grooved propellant is provided with at least one prefabricated groove (1), the prefabricated groove (1) is parallel to the top surface of the cuboid prefabricated grooved propellant, and the prefabricated groove (1) penetrates the front end surface and the rear end surface of the cuboid prefabricated grooved propellant.

2. The cuboid preformed grooved propellant according to claim 1, characterized in that: When the number of prefabricated grooves (1) is greater than or equal to 2, all prefabricated grooves (1) are uniformly distributed from top to bottom, the distance between two adjacent prefabricated grooves (1), the distance between the uppermost prefabricated groove (1) and the top surface of the cuboid prefabricated grooved propellant, and the distance between the lowermost prefabricated groove (1) and the bottom surface of the cuboid prefabricated grooved propellant are equal.

3. The cuboid preformed grooved propellant according to claim 1, characterized in that: The prefabricated grooves (1) are centrally distributed in the horizontal direction, that is, the distance from the left end point of the groove to the left edge of the propellant is equal to the distance from the right end point of the groove to the right edge of the propellant.

4. The cuboid preformed grooved propellant according to claim 1, characterized in that: The thickness of the prefabricated groove (1) is 0.15-0.25 mm.

5. The cuboid preformed grooved propellant according to claim 1, characterized in that: The width of the prefabricated groove (1) accounts for 30-70% of the width of the cuboid prefabricated grooved propellant.

6. The cuboid preformed grooved propellant according to claim 5, characterized in that: The length of the cuboid prefabricated grooved propellant is equal to its width, or the length of the cuboid prefabricated grooved propellant is an integer multiple of its width.

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