Study on extrusion safety characteristics of parallel coaxial twin⁃screws for processing energetic materials

doi:10.19491/j.issn.1001-9278.2025.12.019

Abstract

Abstract:

Improving the safety and efficiency of processing energetic materials in twin⁃screw extruders is critical. This study investigates the impact of process conditions on extrusion safety using a simulation approach with EDEM， Ludovic， and Polyflow softwares. The parallel coaxial twin⁃screw extrusion process was modeled to analyze key parameters， including temperature， pressure， and average residence time of the material during mixing and plastication. Simulation results provide specific safe operating windows： at a screw speed of 12 r/min， the recommended feed rate is 5.6~8.4 kg/h； at 15 r/min， the safe feed rate range is 5.6~11.2 kg/h. Furthermore， the material's physical properties， specifically the power law index and consistency coefficient， were found to significantly influence extrusion safety. Therefore， to enhance process safety， it is recommended to select materials with an appropriate moisture content range tailored to different stages of the actual process.

Key words: energetic materials, parallel coaxial twin screw, simulation, process conditions, safety

CLC Number:

TQ320.66⁺2

LI Minghua, XUE Ping, WANG Bin, ZHAO Rong, HAN Minyuan, ZHANG Shuai, HAN Jingjing. Study on extrusion safety characteristics of parallel coaxial twin⁃screws for processing energetic materials[J]. China Plastics, 2025, 39(12): 119-126.

Figures/Tables 22

Fig.1. Parallel coaxial twin⁃screw extruder screw element combination diagram

Fig.2. Physical Modeling of Parallel Coaxial Twin Screw Extrusion Sections and Processes

参数	涵义	数值
固相物性参数	颗粒直径/mm	5
	泊松比	0.23
	密度/kg·m^-3	600
	杨氏模量/Pa	6.96×10⁹
设备	泊松比	0.3
	密度/kg·m^-3	7 850
	杨氏模量/Pa	2×10¹¹
塑化物料物性参数	比热容/J·（kg·K）^-1	2 790
	密度/kg·m^-3	1 670
	导热系数/W·（m·K）^-1	0.34

Tab.1. Parameterization of the material conveying process

工艺温度	加料段/℃		混合塑化段/℃		均化段/℃
GYWD⁃1	50	50	70	70	80	80
GYWD⁃2	55	55	65	65	75	75
GYWD⁃3	60	60	70	70	80	80
GYWD⁃4	60	60	65	65	75	75
GYWD⁃5	65	65	75	75	85	85

Tab.2. Setting table for different process temperatures

Fig.3. Simulation results under GYWD⁃1 process conditions

工艺温度	最高温度/ ℃	最大压力/ MPa	平均停留时间/ s	比机械能/ kWh·t^-1
GYWD⁃1	103	25.0	253.7	134
GYWD⁃2	103	25.9	252.3	142
GYWD⁃3	104	24.4	253.9	133
GYWD⁃4	103	25.7	252.4	141
GYWD⁃5	106	22.5	256.1	122

Tab.3. Simulation results of parallel coaxial twin⁃screw extrusion equipment at different process temperatures

Fig.4. Ludovic simulation results of maximum temperature and maximum pressure variation with screw speed at different charging rates

Fig.5. Simulation results of charging section of parallel coaxial twin⁃screw extruder under different screw speeds

Fig.6. Simulation results under GYWD⁃4 process conditions

Fig.7. Simulation results under GYWD⁃2 process conditions

Fig.8. Schematic diagram of homogenization section slicing

Fig.9. Curve of average pressure variation along the axial direction at different screw speeds

Fig.10. Curve of average temperature change along the axial direction at different screw speeds

Fig.11. Curve of average shear rate along axial direction at different screw speeds

Fig.12. Simulation results of charging section of parallel coaxial twin⁃screw extruder under different charging rates

Fig.13. Curve of average pressure variation along the axial direction at different charging rates

Fig.14. Curve of average temperature change along the axial direction at different charging rates

Fig.15. Curve of average shear rate along axial direction at different charging rates

Fig.16. Simulation results with different power law exponents

Fig.17. Simulation results with different power law exponents

Fig.18. Simulation results with different consistency factors

Fig.19. Simulation results with different consistency factors

References 15

[1]	姚昕. ASRM实现推进剂连续混合［J］.固体火箭技术，1991（4）：6.
[2]	张方宇. 我国弹药生产技术和装备发展现状及发展对策初探［J］.兵工自动化，2008（4）：1⁃4+7.
	ZHANG F Y. Research on National Ammunition Technology， Current Equipment Situation and Development Strategy.［J］.military⁃industrial automation，2008（4）：1⁃4+7.
[3]	Keating J W， Sage F， Klager K， et al. 复合推进剂连续混合工艺述评［J］.国外固体火箭技术，1981，（04）：117⁃128.
[4]	US） C M （US） J B （US） S R M.Co⁃extrusion of energetic materials using multiple twin screw extruders［P］.US 20020307535，2006⁃6⁃20.
[5]	李建军，朱晋生. 双螺杆技术用于火药生产中的安全分析［J］.兵工安全技术，1997（4）：21⁃23.
[6]	孟红伟. 单基药代料的双螺杆挤出工艺研究［D］.北京理工大学，2016.
[7]	王浩男. NE62型双螺杆挤出机共混挤出ABS/ABS和PC/ABS工艺与优化［D］.北京理工大学，2016.
[8]	林群章. 含能材料同向双螺杆连续混合过程的安全性分析［D］.北京化工大学，2018.
[9]	丁学良，何红，王克俭，等. 单螺杆挤出过程固体粒子输送的离散单元法模拟［J］.塑料，2012，41（5）：92⁃95.
	DING X L， HE H， WANG K J，et al. Discrete element method simulation of solid particle conveying in single screw extrusion process［J］. Plastics，2012，41（5）：92⁃95.
[10]	夏同友. 含能粉体材料自动过筛装置研制［D］.华中科技大学，2021.DOI：10.27157/d.cnki.ghzku.2021.004549 .
[11]	钟婷婷. 双基推进剂螺压挤出成型工艺流变特性的数值模拟研宄［D］.南京理工大学，2015.
[12]	Ji D， Xiao Y， Huang Q， et al. Safety design and numerical simulation of twin screw extruder for energetic materials［J］.Journal of Physics： Conference Series，2020，1507（2）.
[13]	傅陈超. 推进剂代料用双螺杆挤出机混合塑化过程模拟及验证研究［D］.北京化工大学，2024.DOI：10.26939/d.cnki.gbhgu.2024.001677 .
[14]	王晓倩. CL-20基发射药（代料）界面性质及双螺杆挤出工艺数值模拟研究［D］.北京理工大学，2016.DOI：10.26948/d.cnki.gbjlu.2016.000830 .
[15]	Dombe G， Mehilal D， Bhongale C， et al. Application of Twin Screw Extrusion for Continuous Processing of Energetic Materials［J］. Central European Journal of Energetic Materials， 2015，12（3）：507⁃522.