Multistage variable burning rate solid rocket motor and forming method

Patent metadata

Field	Value
Publication number	US-12454928-B2
Application number	US-202418962602-A
Country	US
Kind code	B2
Filing date	Nov 27, 2024
Priority date	Jan 5, 2024
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

The present invention discloses a multistage variable burning rate solid rocket motor and a forming method. A multi-material composite fiber skeleton structure is embedded inside a propellant in the present invention, so that the original burning rate of the propellant presents multistage changes to achieve the function of multistage thrust. The fiber skeleton structure embedded in the solid rocket motor is formed by additive manufacturing, fixed in a combustion chamber, and then charged at one time to complete the forming of a motor grain. The design can greatly increase the burning rates of the propellants of end-burning and bore-burning motors, and can also conduct multistage adjustment for the burning rates of the motors by changing the fiber skeleton and structure, so as to satisfy the requirements of missile weapon systems for multistage power propulsion. The present invention greatly simplifies the technological production process of the existing single-chamber multi-thrust motor.

First claim

The invention claimed is:

1. A multistage variable burning rate solid rocket motor, comprising a combustion chamber case, an insulator, a propellant grain, a fiber skeleton structure and a fixed fiber, wherein
the insulator is bonded on an inner surface of the combustion chamber case;
the fiber skeleton structure is arranged in the combustion chamber case and composed of a plurality of axial fibers perpendicular to an end surface of a main grain and radial fibers parallel to the end surface of the main grain, wherein front ends of the axial fibers are connected with the insulator, and ends of the axial fibers are connected with the fixed fiber; and the radial fibers are distributed along the plurality of axial fibers;
the propellant grain is filled in the combustion chamber case.

2. The multistage variable burning rate solid rocket motor according to claim 1 , wherein the fiber skeleton structure is divided into a plurality of sections with the same structure and different lengths along an axial direction according to the needs of multistage burning rate change; and each section is integrally printed and formed by additive manufacturing mode to form an overall fiber skeleton structure.

3. The multistage variable burning rate solid rocket motor according to claim 2 , wherein the fiber skeleton structure is formed by connecting and combining multiple metal materials with thermal conductivity greater than 100 W/(m·K), and simultaneously satisfies the needs of additive manufacturing and skeleton strength.

4. The multistage variable burning rate solid rocket motor according to claim 3 , wherein the metal materials comprise copper, silver and aluminum.

5. The multistage variable burning rate solid rocket motor according to claim 2 , wherein the fiber skeleton structure is formed by connecting and combining metal materials and non-metal materials with thermal conductivity greater than 100 W/(m·K), and simultaneously satisfies the needs of additive manufacturing and skeleton strength.

6. The multistage variable burning rate solid rocket motor according to claim 5 , wherein when the fiber skeleton structure is combined by multiple metal materials and non-metal materials, carbon fiber materials are used on transition regions of different materials for transition to ensure good connection and uniform transition between two materials; and the non-metal materials comprise graphite and silicon carbide.

7. The multistage variable burning rate solid rocket motor according to claim 1 , wherein the radial fibers of adjacent layers in the fiber skeleton structure are supported and fixed by a plurality of crossed fibers.

8. A forming method of the multistage variable burning rate solid rocket motor according to claim 1 , comprising the following steps:
step 1: according to the needs of multi ballistics of a weapon system, conducting overall design of the multistage variable burning rate solid rocket motor and determining a multistage change range of a burning rate; determining basic burning rate data and a required speed increasing ratio of the propellant grain according to change range of a burning rate, reversely calculating thermal conductivity data of the material according to the speed increasing ratio, selecting the material of the fiber skeleton structure according to the thermal conductivity range, then selecting a combined structure form of the fiber skeleton structure according to the multistage change rule of the burning rate and finally printing a multistage material fiber skeleton structure by additive manufacturing;
step 2: putting the fiber skeleton structure from additive manufacturing into the combustion chamber case; after connecting the front ends of the axial fibers with the insulator through threads of the insulator and connecting the ends with the fixed fiber, making the fixed fiber penetrate through a tooling and then tensioning the fixed fiber; then fixing the fixed fiber with the tooling through the threads of the tooling; and connecting the tooling with the combustion chamber case;
step 3: after vacuuming the combustion chamber case, casting the propellant grain through a charge hole on the tooling by case bonded casting;
step 4: after the propellant grain is completely solidified, removing the threads which connect the fixed fiber in the tooling, then removing the tooling from the combustion chamber case, and finally cutting a part connected with the fixed fiber in the axial fibers to complete the forming of the multistage variable burning rate solid rocket motor.

Assignees

• Univ Dalian Tech

Inventors

• Guo Fengnan
• Ren Yanxiang
• Li Fengrui
• Zhang Hua
• Li Yiming
• Li Wenyu
• Ji Hongfeng
• Fu Lin

Classifications

• F02K9/36 Primary

  Propellant charge supports · CPC title

• B33Y80/00

  Products made by additive manufacturing · CPC title

• B33Y10/00

  Processes of additive manufacturing · CPC title

• Y02P10/25

  Process efficiency · CPC title

• F02K9/34

  Casings; Combustion chambers; Liners thereof · CPC title