A forming core mold and forming method for a radial annular groove grain of a solid rocket motor

Abstract

The present invention discloses a forming core mold and a forming method for a radial annular groove grain of a solid rocket motor, belonging to the technical field of aerospace. The present invention combines a combustible core mold assembly with an ablatable core mold. By using the ablatability of the ablatable core mold, strength support is provided during the propellant loading process, enabling the grain to form a specific structure. After the propellant loading, it is removed by ablation. The combustible core mold assembly, on the one hand, provides protection for the grain during the removal process of the ablatable core mold, and on the other hand, burns rapidly after the engine ignition without affecting the internal ballistic characteristics of the engine. The present invention solves the problem of difficult forming of the radial annular groove grain, and can realize the rapid forming and production of multiple radial annular groove grain structures; the present invention can realize the rapid preparation of complex grain structures such as radial annular grooves, providing a rapid and efficient means for the design and production of complex grain structures. At the same time, compared with the existing disassembled combined core mold, this method can improve the production efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace technology, and relates to a forming method for the core mold structure of a solid rocket motor, and particularly to a forming method for a special type of annular groove grain structure. Background Art

[0002] Generally, a solid rocket motor realizes its specific thrust characteristics through the design of the grain structure. The radial annular groove grain structure is a new type of grain structure, which can significantly reduce the stress level of a high loading grain structure. Through calculation, it can be known that under the condition of the same loading ratio, the maximum stress of the radial annular groove grain structure is reduced by more than 5% compared with the finned grain structure. Although this grain structure has certain advantages in reducing the grain stress level, at present, the application of this kind of charge structure in missile motors is not very extensive, and the main reason is that there are many difficulties in the process implementation of this special grain structure.

[0003] At present, the forming of the grain structure of a solid rocket motor generally adopts the process mode of combined core mold demolding. However, for a grain structure containing multiple complex radial annular grooves, due to the narrow central inner hole of the radial annular groove grain structure and the complex radial annular groove structure, the traditional core mold demolding method cannot effectively demold. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a combustible and ablatable combined forming core mold and a forming method. This forming core mold can realize the rapid preparation of multiple radial annular groove grain structures, achieving the effect of reducing the internal stress of the grain. The present invention combines a combustible core mold component with an ablatable core mold. By utilizing the ablatability of the ablatable core mold, it provides certain strength support during the charging process, enabling the grain to form a specific structure, and removing it by ablation after charging. The combustible core mold component, on the one hand, protects the grain during the removal process of the ablatable core mold, and on the other hand, burns rapidly after the engine ignition without affecting the internal ballistic characteristics of the engine.

[0005] The technical solution of the present invention:

[0006] A forming core mold for a radial annular groove grain of a solid rocket motor includes a radial annular groove core mold component 1, a main core rod 2, a connection and sealing structure 3, a solution pipeline 4, and a suction hose 5.

[0007] The main core rod 2 is a hollow cylindrical structure, which is installed in the middle of the combustion chamber housing 11 and is used to fix the radial annular groove core mold component 1 during the forming process of the radial annular groove grain, and the main core rod 2 is disassembled after the radial annular groove grain is cured.

[0008] The described radial annular groove core mold assembly 1 includes a combustible core mold assembly housing 6 and an ablatable core mold assembly 7; both the combustible core mold assembly housing 6 and the ablatable core mold assembly 7 are circular rings, and the combustible core mold assembly housing 6 is closely attached to the outside of the ablatable core mold assembly 7; internal communication holes and surface grooves are provided in the ablatable core mold assembly 7 to facilitate rapid ablation when encountering a solution.

[0009] The described connection and sealing structure 3 includes a connection bolt 8 and a sealing ring 9, which are used to connect the radial annular groove core mold assembly 1 to the main mandrel 2. A connection hole 10 is provided at the connection position between the main mandrel 2 and the radial annular groove core mold assembly 1.

[0010] The solution channel 4 is connected to the connection hole 10 position of the main mandrel 2 and is in communication with the connection hole 10; after the charge is completed, a solution is injected into the inside of the radial annular groove core mold assembly 1 through the solution channel 4. The extraction hose 5 is arranged inside the solution channel 4. After the ablatable core mold assembly 7 is completely ablated, the solution inside the combustible core mold assembly housing 6 is extracted through the extraction hose 5. The solution should have good dissolution characteristics for the ablatable core mold material, and in this solution environment, the ablatable core mold material is easy to ablate.

[0011] Further, the combustible core mold assembly housing 6 is made of a cellulose-based material with a lower ignition point and meets the requirements of additive manufacturing; preferably materials such as celluloid.

[0012] Further, the ablatable core mold assembly 7 is made of a water-soluble polymer material and has a strong bonding property with the combustible core mold assembly housing 3; preferably materials such as polylactic acid.

[0013] Further, a plurality of the radial annular groove core mold assemblies 1 are provided.

[0014] Further, for a combustion chamber structure with smaller front and rear openings, the radial annular groove core mold assembly 1 is set in a split docking form to facilitate placement through the combustion chamber opening.

[0015] Using the above-mentioned solid rocket engine radial annular groove grain forming core mold, a method for forming a radial annular groove grain structure includes the following steps:

[0016] Step 1: Design the combustible core mold assembly housing 6 and the ablatable core mold assembly 7 according to the matching of the radial annular groove grain structure;

[0017] Step 2: Integrally prepare the combustible core mold assembly housing 6 and the ablatable core mold assembly 7 by additive manufacturing; or separately prepare the combustible core mold assembly housing 6 and the ablatable core mold assembly 7 by the mold method and reliably bond the two components with an adhesive to form the radial annular groove core mold assembly 1;

[0018] Step 3: Design and machine the main mandrel 2 according to the inner hole structure of the radial annular groove grain, and open a connection hole 10 at the position where the main mandrel 2 is connected to the radial annular groove core mold assembly 1;

[0019] Step 4: Place the extraction hose 5 inside the solution channel 4, and during the placement process, the length of the hose does not exceed that of the solution channel 4;

[0020] Step 5: Tightly connect the solution channel 4 to the connection hole 10 of the main mandrel 2;

[0021] Step 6: Assemble the radial annular groove core mold assembly 1 and the main mandrel 2 through the connection sealing structure 3, and install them together inside the combustion chamber shell 11;

[0022] Step 7: Pour and cure the grain 12 according to the requirements;

[0023] Step 8: After the grain 12 is completely cured, inject the solution that can dissolve the core mold material into the solution channel 4, slowly rotate the combustion chamber to make the solution fully contact with the dissolvable core mold assembly 7, and complete the complete ablation of the core mold;

[0024] Step 9: Use the extraction hose 5 to extract the solution inside the radial annular groove core mold assembly 1, and if necessary, insert the extraction hose 5 deep into the radial annular groove core mold assembly 1 for extraction;

[0025] Step 10: After the extraction is completed, disassemble the connection sealing structure 3, take out the main mandrel 2 from the combustion chamber, and complete the formation of the grain 12 structure.

[0026] Advantages of the present invention: The present invention solves the problem of difficult forming of the radial annular groove grain, and can realize the rapid forming and production of multiple radial annular groove grain structures; the present invention can realize the rapid preparation of complex grain structures such as radial annular grooves, provides a rapid and efficient means for the design and production of complex grain structures, and can improve the production efficiency compared with the existing disassembled combined core mold. Description of the Drawings

[0027] Figure 1 It is a sectional view of the combustion chamber structure of a typical solid rocket motor with a radial annular groove grain.

[0028] Figure 2 It is a sectional view of the forming core mold of a solid rocket motor.

[0029] Figure 3 It is a sectional view of the connection between the radial annular groove core mold assembly and the main mandrel.

[0030] Figure 4 It is a detailed view of the forming core mold of a solid rocket motor.

[0031] Figure 5It is a schematic diagram of the forming of the radial annular groove grain structure for a solid rocket motor.

[0032] Figure 6 It is a schematic diagram of the formed core mold after ablation of the ablatable core mold assembly.

[0033] In the figure: 1 Radial annular groove core mold assembly; 2 Main core rod; 3 Connection and sealing structure; 4 Solution channel; 5 Extraction hose; 6 Outer shell of the combustible core mold assembly; 7 Ablatable core mold assembly; 8 Connection bolt; 9 Sealing ring; 10 Connection hole; 11 Combustion chamber shell; 12 Grain. Detailed implementation manners

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following will combine with the accompanying drawings to describe in detail the specific implementation manners of the present invention.

[0035] As Figure 2-3 shown, a forming core mold for a radial annular groove grain of a solid rocket motor includes a radial annular groove core mold assembly 1, a main core rod 2, a connection and sealing structure 3, a solution pipeline 4 and an extraction hose 5.

[0036] As Figure 4 shown, the radial annular groove core mold assembly 1 is an annular structure composed of an outer shell 6 of the combustible core mold assembly and an ablatable core mold assembly 7, and the outer shell 6 of the combustible core mold assembly is closely attached to the outside of the ablatable core mold assembly 7; internal communication holes and surface grooves are provided in the ablatable core mold assembly 7 to facilitate rapid ablation after encountering the solution.

[0037] The main core rod 2 is a hollow cylindrical structure, which is installed in the middle of the combustion chamber shell 11, and a connection hole 10 is provided at the connection position with the radial annular groove core mold assembly 1. The solution channel 4 is connected to the main core rod 2 through the connection hole 10, and the extraction hose 5 is located inside the solution channel 4. The connection and sealing structure 3 includes a connection bolt 8 and a sealing ring 9 for connecting the radial annular groove core mold assembly 1 and the main core rod 2.

[0038] As Figure 5 、 Figure 6 shown, after the charging is completed, a solution is injected into the ablatable core mold assembly 7. After the ablatable core mold assembly 7 is completely ablated, the extraction hose 5 is used to extract the solution inside the radial annular groove core mold assembly 1.

[0039] Using the above-mentioned forming core mold for the radial annular groove grain of a solid rocket motor, the method for forming the radial annular groove grain includes the following steps:

[0040] Step 1: Design the outer shell 6 of the combustible core mold assembly and the ablatable core mold assembly 7 according to the structure of the radial annular groove grain.

[0041] Step 2: Integrally prepare the combustible core mold component housing 6 and the ablatable core mold component 7 by an additive manufacturing method; or separately prepare the combustible core mold component housing 6 and the ablatable core mold component 7 by a mold method, and reliably bond the two components with an adhesive to form a radial annular groove core mold component 1;

[0042] Step 3: Design and machine the main mandrel 2 according to the matching of the inner hole structure of the radial annular groove grain, and set a connection hole 10 at the position where the main mandrel 2 is connected to the radial annular groove core mold component 1;

[0043] Step 4: Place the extraction hose 5 inside the solution channel 4, and the length of the hose does not exceed the solution channel 4 during the placement process;

[0044] Step 5: Tightly connect the solution channel 4 to the connection hole 10 of the main mandrel 2;

[0045] Step 6: Assemble the radial annular groove core mold component 1 and the main mandrel 2 through the connection sealing structure 3, and install them together inside the combustion chamber housing 11;

[0046] Step 7: Pour and cure the grain 12 according to the requirements;

[0047] Step 8: After the grain 12 is completely cured, inject the solution of the ablatable core mold material into the solution channel 4, slowly rotate the combustion chamber to make the solution fully contact with the ablatable core mold component 7, and complete the complete ablation of the core mold;

[0048] Step 9: Use the extraction hose 5 to extract the solution inside the radial annular groove core mold component 1, and if necessary, insert the extraction hose 5 deep into the radial annular groove core mold component 1 for extraction;

[0049] Step 10: After the extraction is completed, disassemble the connection sealing structure 3, take out the main mandrel 2 from the combustion chamber, and complete the forming of the grain 12 structure.

Claims

1. A forming core mold for a radial annular groove grain of a solid rocket motor, characterized in that The formed core mold includes a radial annular groove core mold assembly (1), a main core rod (2), a connection sealing structure (3), a solution channel (4), and a suction hose (5); The main core rod (2) is a hollow cylindrical structure and is installed in the middle of the combustion chamber housing; The radial annular groove core mold assembly (1) includes a combustible core mold assembly housing (6) and an ablatable core mold assembly (7); both the combustible core mold assembly housing (6) and the ablatable core mold assembly (7) are circular rings, and the combustible core mold assembly housing (6) is closely attached to the outside of the ablatable core mold assembly (7); internal communication holes and surface grooves are provided in the ablatable core mold assembly (7) to facilitate rapid ablation when encountering the solution; The connection sealing structure (3) includes connection bolts (8) and sealing rings (9) for connecting the radial annular groove core mold assembly (1) to the main core rod (2); connection holes (10) are provided at the connection position between the main core rod (2) and the radial annular groove core mold assembly (1); The solution channel (4) is connected to the connection hole (10) position of the main core rod (2) and communicates with the connection hole (10); after the charge is completed, the solution is injected into the inside of the radial annular groove core mold assembly (1) through the solution channel (4); The suction hose (5) is arranged inside the solution channel (4). After the ablatable core mold assembly (7) is completely ablated, the solution inside the radial annular groove core mold assembly (1) is extracted through the suction hose (5).

2. The forming core mold for the radial annular groove grain of a solid rocket motor according to claim 1, wherein The combustible core mold assembly housing (6) is made of cellulose-based materials; the ablatable core mold assembly (7) is made of water-soluble polymer materials.

3. A forming core mold for a radial annular groove grain of a solid rocket motor according to claim 1 or 2, characterized in that, A plurality of the radial annular groove core mold assemblies (1) are provided.

4. A forming core mold for a radial annular groove grain of a solid rocket motor according to claim 1 or 2, characterized in that, For combustion chambers with smaller front and rear openings, the radial annular groove core mold assembly (1) is arranged in a split docking form to facilitate placement through the combustion chamber opening.

5. A method for forming a solid rocket motor radial annular groove grain using a forming core mold as described in any one of claims 1-4, characterized in that, The method includes the following steps: Step 1: Design the combustible core mold assembly housing (6) and the ablatable core mold assembly (7) according to the structure of the radial annular groove grain; Step 2: Integrally prepare the combustible core mold assembly housing (6) and the ablatable core mold assembly (7) by additive manufacturing; Step 3: Design and machine the main core rod (2) according to the inner hole structure of the radial annular groove grain, and open connection holes (10) at the connection positions between the main core rod (2) and the radial annular groove core mold assembly (1); Step 4: Place the suction hose (5) inside the solution channel (4), and the length of the hose during placement does not exceed the solution channel (4); Step 5: Tightly connect the solution channel (4) to the connection hole (10) position of the main core rod (2); Step 6: Assemble the radial annular groove core mold assembly (1) and the main core rod (2) through the connection sealing structure (3) and install them together inside the combustion chamber housing; Step 7: Pour and cure the grain according to requirements; Step 8: After the grain is completely cured, inject the solution of the ablatable core mold material into the solution channel (4), slowly rotate the combustion chamber to make the solution fully contact with the ablatable core mold assembly (7), and complete the complete ablation of the core mold; Step 9: Extract the solution inside the radial annular groove core mold assembly (1) using the suction hose (5); Step 10: After the extraction is completed, disassemble the connection sealing structure (3), take out the main mandrel (2) from the combustion chamber, and complete the forming of the grain structure.

6. The method according to claim 5, wherein In the said Step 2, either the combustible core mold assembly shell (6) and the ablatable core mold assembly (7) are respectively prepared by the mold method, and the two assemblies are reliably bonded by an adhesive to form a radial annular groove core mold assembly (1).

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