A propellant structure and solid rocket motor that eliminates free-loading erosion combustion

Abstract

This invention provides a propellant loading structure and a solid rocket motor that eliminates erosive combustion during free-loading. The propellant loading structure includes a propellant grain with a central inner hole coaxially extending through both ends. A U-shaped slot is formed at one end of the propellant grain, penetrating the sidewall and communicating with the central inner hole. This invention, by designing the propellant grain structure and creating a U-shaped slot at the end close to the deflector plate, and connecting the U-shaped slot to the gas passage of the deflector plate, eliminates erosive combustion that occurs during densely packed propellant loading.

Description

Technical Field

[0001] This invention belongs to the field of rocket engine propellant technology, specifically relating to a propellant structure and solid rocket engine that eliminates free-loading erosion combustion. Background Technology

[0002] When a solid rocket motor uses a freely loaded tubular double-base propellant, a baffle is placed in front of the nozzle to prevent the double-base propellant from moving backward and blocking the nozzle throat during engine operation, which could cause abnormal engine operation or even an explosion.

[0003] When an engine uses a small-diameter tubular double-base propellant and the combustion chamber cross-sectional area is packed with a large density, the area of ​​the gas passage on the baffle plate is often limited to prevent the small-diameter propellant from flowing directly out of the baffle plate's gas passage. In the design of the baffle plate, the inner hole area of ​​the tubular double-base propellant is generally 100% directly connected to the gas passage of the baffle plate, allowing the gas produced by combustion within the propellant's inner hole to be smoothly discharged to the nozzle. However, to prevent the propellant from moving backward, the baffle plate must be in solid contact with the propellant, thus limiting the passage area of ​​the gas produced by combustion on the outer surface of the propellant. This restricts the area of ​​direct communication between the outer passage area of ​​the propellant and the gas passage area of ​​the baffle plate, preventing the rapid discharge of external gas and potentially leading to corrosive combustion, abnormally high pressure within the combustion chamber, and even the destruction and disintegration of the combustion chamber shell. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem that existing small-diameter tubular double-base propellant grains are prone to erosion and combustion when the packing density is high, which can cause a significant increase in the internal pressure of the engine and lead to the destruction and disintegration of the engine casing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A propellant charge structure for eliminating free-loading erosion combustion includes a propellant grain, wherein a central inner hole is coaxially formed on the propellant grain, penetrating both ends of the propellant grain, and a U-shaped slot is formed at one end of the propellant grain, the U-shaped slot penetrating the side wall of the propellant grain and communicating with the central inner hole.

[0007] Furthermore, the diameter of the central inner hole is D, the width L of the U-shaped groove is 0.2D to 3D, and the depth H of the U-shaped groove is 0.5D to 25D.

[0008] Furthermore, the center of the U-shaped groove is located on the axis of the propellant grain.

[0009] Furthermore, the depth direction of the U-shaped groove is parallel to the axial direction of the propellant grain.

[0010] Furthermore, the propellant grain is a double-base propellant grain.

[0011] In addition, the present invention also provides a solid rocket motor for eliminating free-loading erosion combustion, comprising a propellant combustion chamber, a baffle plate, a nozzle assembly, and the aforementioned propellant loading structure. The nozzle assembly is installed at the outlet end of the propellant combustion chamber, the baffle plate is located between the nozzle assembly and the propellant combustion chamber, the baffle plate is provided with a gas passage, the propellant grain is filled into the propellant combustion chamber, the U-shaped slot faces the baffle plate, and the central inner hole and at least part of the U-shaped slot communicate with the gas passage.

[0012] Furthermore, the combustion chamber is filled with several sets of annular propellant columns, each set of propellant columns is arranged coaxially along the radial direction of the combustion chamber, and each set of propellant columns consists of multiple propellant columns arranged circumferentially along the combustion chamber.

[0013] Furthermore, the U-shaped slots on each propellant grain of each propellant grain group are arranged in a circular pattern.

[0014] Furthermore, the baffle plate is provided with several sets of annular gas passage groups, each of which is arranged coaxially at radial intervals along the combustion cylinder of the propellant charge. Each set of gas passage groups consists of multiple gas passages arranged at intervals along the circumference of the combustion cylinder of the propellant charge.

[0015] Furthermore, the gas passage is an arc-shaped groove extending circumferentially along the combustion cylinder, and the width of the arc-shaped groove is greater than the diameter of the central inner hole.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] (1) The present invention designs the structure of the propellant grain, opens a U-shaped slot at one end of the propellant grain close to the baffle plate, and connects the U-shaped slot with the gas passage of the baffle plate, thereby eliminating the erosion and combustion caused by dense loading of propellant grains.

[0018] (2) The charge structure provided by the present invention, which eliminates free filling erosion and combustion, can be processed on a general CNC machine tool. It has a simple structure, is easy to process and inspect, and the product quality can be guaranteed.

[0019] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a front view of the charge structure of the present invention that eliminates free-filling erosion combustion;

[0021] Figure 2This is a right view of the charge structure of the present invention that eliminates free-filling erosion combustion;

[0022] Figure 3 yes Figure 1 Cross-sectional view of AA;

[0023] Figure 4 This is a schematic diagram of the solid rocket motor of the present invention that eliminates free-loading erosion combustion;

[0024] Figure 5 yes Figure 4 Cross-sectional view of BB;

[0025] Figure 6 yes Figure 4 Cross-sectional view of CC.

[0026] Explanation of reference numerals in the attached diagram: 1. Propellant grain; 2. U-shaped groove; 3. Central inner hole; 4. Combustion chamber; 5. Baffle plate; 6. Gas passage. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an abutting connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. In the description of this invention, unless otherwise stated, "a plurality of" or "several" means two or more.

[0030] Example 1:

[0031] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment provides a propellant loading structure to eliminate free-loading erosion combustion, including a propellant grain 1. The propellant grain 1 has a central inner hole 3 coaxially extending through both ends. One end of the propellant grain 1 has a U-shaped slot 2, which extends through the sidewall of the propellant grain 1 and communicates with the central inner hole 3. The propellant grain 1 is a double-base propellant grain. To address the problem of erosion combustion that easily occurs with double-base propellant grains when the free-loading density is high, this embodiment's loading structure, during operation, places the end of the propellant grain 1 with the U-shaped slot 2 close to a baffle plate. Simultaneously, the central inner hole 3 and the U-shaped slot 2 of the propellant grain 1 are directly connected to the gas passage on the baffle plate. The central inner hole 3 allows the gas generated by combustion within the propellant grain 1 to be smoothly discharged into the nozzle, while the U-shaped slot 2 allows the gas generated by combustion on the outer surface of the propellant grain 1 to be quickly and directly discharged into the nozzle, thus effectively preventing erosion combustion. The propellant loading structure provided in this embodiment, which eliminates free-loading erosion combustion, has a U-shaped groove 2 on the end face of the propellant grain 1. It can be machined on a general CNC machine tool. The structure is simple, easy to process and inspect, and the product quality can be guaranteed.

[0032] Specifically, the diameter of the central inner hole 3 of the propellant grain 1 is D, the width L of the U-shaped groove 2 is 0.2D to 3D, and the depth H of the U-shaped groove 2 is 0.5D to 25D. For the structural dimension design of the U-shaped groove 2, it is necessary to ensure that the quotient of the combustion area of ​​the outer surface of the propellant grain 1 divided by the area of ​​the gas flow channel generated by the combustion surface is not greater than 100. The area of ​​the gas flow channel generated by the combustion of the outer surface of the propellant grain 1 is the sum of the gas channel areas of the part of the baffle plate that communicates with the U-shaped groove 2 of the propellant grain 1.

[0033] Preferably, the depth direction of the U-shaped slot 2 is designed to be parallel to the axial direction of the propellant grain 1. The center of the U-shaped slot 2 is located on the axis of the propellant grain 1. Specifically, in some embodiments, the U-shaped slot 2 can be designed as a straight structure, extending radially along the propellant grain 1. This type of U-shaped slot 2 not only has a large opening area, which facilitates a larger direct connection between the U-shaped slot 2 and the gas passage of the baffle plate 5 during propellant grain filling, but also facilitates processing. In other embodiments, the U-shaped slot 2 can also be designed with a certain curvature, so that when multiple propellant grains 1 are filled in the solid rocket engine, the U-shaped slots 2 on each propellant grain 1 can form a common circle, thereby directly connecting a larger area with the gas passage of the baffle plate 5, and thus improving the exhaust efficiency of the gas generated by combustion on the outer surface of the propellant grain 1.

[0034] Example 2:

[0035] like Figure 4 , Figure 5 and Figure 6 As shown, this embodiment provides a solid rocket motor that eliminates free-loading erosion combustion, including a propellant combustion chamber 4, a baffle plate 5, a nozzle assembly, and the propellant loading structure described in the above embodiment. The nozzle assembly is installed at the outlet end of the propellant combustion chamber 4, the baffle plate 5 is located between the nozzle assembly and the propellant combustion chamber 4, and the baffle plate 5 has a gas passage 6. The propellant grain 1 is filled inside the propellant combustion chamber 4, and one end of the propellant grain 1 with a U-shaped slot 2 faces and is close to the baffle plate 5. The central inner hole 3 and at least part of the U-shaped slot 2 of the propellant grain 1 are connected to the baffle plate 5. The gas passage 6 is connected; in this embodiment, the solid part of the propellant grain 1 contacts the baffle plate 5, thereby preventing the propellant grain 1 from moving backward and blocking the nozzle assembly. At the same time, the central inner hole 3 and the U-shaped groove 2 of the propellant grain 1 are connected to the gas passage 6 of the baffle plate 5. The gas generated by the combustion of the propellant grain 1 in the inner hole can be smoothly discharged to the nozzle assembly through the central inner hole 3. The gas generated by the combustion of the propellant grain 1 on the outer surface can also be directly and quickly discharged through the U-shaped groove 2. This can eliminate the erosion and combustion phenomenon of the dense propellant grain 1 filled in the combustion cylinder 4 when the engine is working, and ensure the normal and safe operation of the engine.

[0036] In an optimized implementation, the combustion chamber 4 is filled with several sets of annular propellant column groups. Each propellant column group is coaxially arranged radially along the combustion chamber 4, and each group consists of multiple propellant columns 1 arranged circumferentially along the combustion chamber 4. Correspondingly, the baffle plate 5 is provided with several sets of annular gas passage groups. Each gas passage group is coaxially arranged at intervals radially along the combustion chamber 4, and each group consists of multiple gas passages 6 arranged at intervals circumferentially along the combustion chamber 4. When the propellant columns 1 are filled into the combustion chamber 4, the propellant columns 1 and the gas passages 6 on the baffle plate 5 have a certain correspondence, that is, the area of ​​the central inner hole 3 of each propellant column 1 can be completely connected with the gas passage 6 of the baffle plate 5, and at the same time, the U-shaped slot 2 of each propellant column 1 is directly connected to the gas passage 6 of the baffle plate 5 with the largest possible area.

[0037] Specifically, the gas passage 6 is designed as an arc-shaped groove extending circumferentially along the combustion cylinder 4, and the width of the arc-shaped groove is greater than the diameter of the central inner hole 3 of the propellant column 1, ensuring that the area of ​​the central inner hole 3 of the propellant column 1 is completely connected with the gas passage 6 of the baffle plate 5.

[0038] Preferably, the U-shaped slots 2 on each propellant grain 1 of each propellant grain group are arranged in a cocircular pattern. In this case, the cross-section of the U-shaped slots 2 on each propellant grain 1 is arc-shaped. The cocircular U-shaped slots 2 facilitate correspondence with the corresponding gas passage groups on the baffle plate, thereby ensuring that the U-shaped slots 2 of each propellant grain 1 are directly connected to the gas passages 6 of the baffle plate 5 with the maximum area. Of course, when the U-shaped slots 2 on each propellant grain 1 are straight, the U-shaped slots 2 on each propellant grain 1 of each propellant grain group can be designed to be tangent to the same reference circle, which is coaxial with the propellant combustion cylinder 4.

[0039] The effects of using the propellant grain with a U-shaped groove in this invention are illustrated below through specific embodiments.

[0040] The combustion chamber of a certain engine has an inner diameter of Φ69.2mm and is filled with 34 tubular propellant grains. Each propellant grain is 54mm long, has a central inner diameter of Φ4.15mm, and an outer diameter of 9.75mm. Before adopting conventional propellant grains (i.e., without U-shaped notches on the propellant grain end face), the engine's maximum operating pressure reached 29.4MPa. However, when using the propellant grains of this invention, with U-shaped notches on the propellant grain end face (U-shaped notches with a width L of 4mm and a depth H of 6mm), the maximum operating pressure is only about 11MPa, which matches the theoretical calculation curve.

[0041] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A solid rocket motor that eliminates free-loading erosion combustion, characterized in that: The device includes a propellant combustion cylinder, a baffle plate, a nozzle assembly, and a propellant loading structure. The propellant loading structure includes a propellant grain with a central inner hole coaxially extending through both ends. One end of the propellant grain has a U-shaped slot that extends through the sidewall of the propellant grain and communicates with the central inner hole. The nozzle assembly is installed at the outlet end of the propellant combustion cylinder. The baffle plate is located between the nozzle assembly and the propellant combustion cylinder and has a gas passage. The propellant grain is filled into the propellant combustion cylinder, with the U-shaped slot facing the baffle plate. The central inner hole and at least part of the U-shaped slot communicate with the gas passage. The propellant combustion cylinder contains several sets of annular propellant grain groups, each set of propellant grains arranged coaxially along the radial direction of the propellant combustion cylinder. Each set of propellant grains consists of multiple propellant grains arranged circumferentially along the propellant combustion cylinder.

2. The solid rocket motor as described in claim 1, characterized in that: The diameter of the central inner hole is D, the width L of the U-shaped groove is 0.2D to 3D, and the depth H of the U-shaped groove is 0.5D to 25D.

3. The solid rocket motor as described in claim 1, characterized in that: The center of the U-shaped groove is located on the axis of the propellant grain.

4. The solid rocket motor as described in claim 1, characterized in that: The depth direction of the U-shaped groove is parallel to the axial direction of the propellant grain.

5. The solid rocket motor as described in claim 1, characterized in that: The propellant grains are double-base propellant grains.

6. The solid rocket motor as described in claim 1, characterized in that: The U-shaped slots on each propellant grain in each propellant grain group are arranged in a circular pattern.

7. The solid rocket motor as described in claim 1, characterized in that: The baffle plate is provided with several sets of annular gas passage groups. Each set of gas passage groups is arranged coaxially at radial intervals along the combustion cylinder of the charge. Each set of gas passage groups consists of multiple gas passages arranged at intervals along the circumference of the combustion cylinder of the charge.

8. The solid rocket motor as described in claim 7, characterized in that: The gas passage is an arc-shaped groove extending circumferentially along the combustion cylinder, and the width of the arc-shaped groove is greater than the diameter of the central inner hole.

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