Analysis of Propellant Pellets’ Dispersion Characteristics of Single Modular Charge Based on Discrete Element Method for Non-Spherical Particles

doi:10.12382/bgxb.2022.0015

Abstract

Abstract:

A three-dimensional unsteady gas-solid two-phase flow model is proposed to investigate the distribution and stacking characteristics of propellant pellets during the ignition and flame-spreading processes of a single modular charge in the uni-modular charge. Numerical simulations are carried out under different initial conditions at the filling positions of modular cartridges, in which cylindrical pellets are constructed by the multi-element method. The numerical results obtained by the discrete element method (DEM) indicate good agreement with the experimental results, and that the cylindrical particle model is more accurate than the spherical particle model. The simulation results suggest that: when the modular cartridge’s initial loading location is 10mm, 40mm, 70mm, and 100mm from the primer, the pellets are finally distributed on the outside of the right end of the cartridge, showing horizontal and sloped stacking in turn; the axial length of horizontal stacking is reduced from 293.3mm to 203.8mm, and the angle of the sloped stacking decreases from 22.01° to 19.82° when the distance between the initial loading position of the modular cartridge and the primer increases from 10mm to 100mm; in other words, as the modular cartridge moves to the right, the starting point of horizontal stacking moves to the right, and the axial length decreases linearly; however, the axial length of sloped stacking is almost unchanged, and the slope becomes flat.

Key words: artillery, modular charge, discrete element method, cylindrical particles

LI Ziyu, YU Yonggang. Analysis of Propellant Pellets’ Dispersion Characteristics of Single Modular Charge Based on Discrete Element Method for Non-Spherical Particles[J]. Acta Armamentarii, 2023, 44(5): 1330-1338.

Figures/Tables 14

Fig.1 Schematic diagram of a visual experimental platform for the ignition and flame-spreading process

Fig.2 Diagram of the cylindrical propellent pellets

Fig.3 Collision mechanism of cylindrical particles

Fig.4 Diagram of forces and motion of the cylinder pellet

Fig.5 Schematic diagram of experimental devices

Fig.6 Geometry of the calculation model and the cylindrical pellet model

Fig.7 Sequence diagram of the modular charge’s ignition and flame-spreading experiment at 1000ms[20]

Fig.8 Front view of propellant pellets’ final distribution (l0=40mm)

Fig.9 Exprimental and numerical values of propellant pellets’ stacking height

Fig.10 Pressure distribution of the Z=0mm section in the chamber at different moments

Fig.11 Velocity and distribution of propellant pellets in the chamber at different moments

Fig.12 Distribution of pellets under different working conditions

Table 1 Characteristic parameters of propellant pellet stacking

序号	装填轴向位置 l₀/mm	水平轴向堆积长度L/mm	坡状堆积坡度角 α/(°)
1	10	293.3	22.01
2	40	264.6	21.22
3	70	229.7	20.73
4	100	203.8	19.82

Fig.13 Relationship between the axial length of the horizontal stacking of propellant pellets and the horizontal loading position of the modular cartridge

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