Mesoscale study on explosion-induced formation and thermochemical response of PTFE/Al granular jet

Abstract

The dynamic formation, shock-induced inhomogeneous temperature rise and corresponding chemical reaction behaviors of PTFE/Al reactive liner shaped charge jet (RLSCJ) are investigated by the combination of mesoscale simulation, reaction kinetics and chemical energy release test. A two-dimensional granular model is developed with the randomly normal distribution of aluminum particle sizes and the particle delivery program. Then, the granular model is employed to study the shock-induced thermal behavior during the formation and extension processes of RLSCJ, as well as the temperature history curves of aluminum particles. The simulation results visualize the motion and temperature responses of the RLSCJ at the grain level, and further indicate that the aluminum particles are more likely to gather in the last two-thirds of the jet along its axis. Further analysis shows that the shock, collision, friction and deformation behaviors are all responsible for the steep temperature rise of the reactive jet. In addition, a shock-induced chemical reaction extent model of RLSCJ is built based on the combination of the Arrhenius model and the Avrami-Erofeev kinetic model, by which the chemical reaction growth behavior during the formation and extension stages is described quantitatively. The model indicates the reaction extent highly corresponds to the aluminum particle temperature history at the formation and extension stages. At last, a manometry chamber and the corresponding energy release model are used together to study the macroscopic chemical energy release characteristics of RLSCJ, by which the reaction extent model is verified.