Explosively dispersed granular materials frequently exhibit coherent particle clustering and jetting structures. Influencing the mass concentration and related particle reaction and energy release, this phenomenon is of significant interest to… Click to show full abstract
Explosively dispersed granular materials frequently exhibit coherent particle clustering and jetting structures. Influencing the mass concentration and related particle reaction and energy release, this phenomenon is of significant interest to the study of flow instability and mixing in heterogeneous detonation and explosion. Largely inhibited by the complex mesoscale multiphase interactions involved in the dispersal process, the underlying mechanism remains unclear. In this study, mesoscale direct simulations that capture coupled multiphase interactions and deterministic granular dynamics are conducted to investigate particle clustering and jetting formation in explosively dispersed granular payloads consisting of inert particles. Employing a mesoscale simulation framework that models particles as discrete entities and resolves the interfaces and collisions of individual particles in stochastically generated payloads with randomly distributed particle positions and sizes, numerical cases that cover a set of stochastic payloads, burster states, and coefficients of restitution are solved and analyzed. A valid statistical dissipative property of the mesoscale discrete modeling with respect to Gurney velocity is demonstrated. The predicted surface expansion velocities can extend the time range of the velocity scaling law with regard to Gurney energy in the Gurney theory from the steady-state termination phase to the unsteady evolution phase. Dissipation analysis based on the mesoscale discrete modeling of granular payloads suggests that incorporating the effects of porosity can enhance the prediction of Gurney velocity for explosively dispersed granular payloads. On the basis of direct simulations, an explanation for particle clustering and jetting formation is proposed to increase the understanding of established experimental observations in the literature.Explosively dispersed granular materials frequently exhibit coherent particle clustering and jetting structures. Influencing the mass concentration and related particle reaction and energy release, this phenomenon is of significant interest to the study of flow instability and mixing in heterogeneous detonation and explosion. Largely inhibited by the complex mesoscale multiphase interactions involved in the dispersal process, the underlying mechanism remains unclear. In this study, mesoscale direct simulations that capture coupled multiphase interactions and deterministic granular dynamics are conducted to investigate particle clustering and jetting formation in explosively dispersed granular payloads consisting of inert particles. Employing a mesoscale simulation framework that models particles as discrete entities and resolves the interfaces and collisions of individual particles in stochastically generated payloads with randomly distributed particle positions and sizes, numerical cases that cover a set...
               
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