论文部分内容阅读
A multiscale model is utilized to analyze the compaction processes in granular FPVIX beds composed of different particle sizes .In present study, we extend the localization strategy of Gonthier to account for the effect of compressibility and solid-liquid phase change at grain scale on localized heating. Analysis of the steady-state wave structure indicates that the compaction behavior of a porous material is particle-size dependent It is found that for solid volume fraction<0.88, the fine particle beds provide greater resistance to compaction than coarse beds and propagate compaction waves that traveled at faster speeds. When >0.88, the difference in behavior is small;suggesting the physical state of the compacted bed had become very similar for the two materials. The evolution of the grain scale response is tracked. For subsonic compaction waves, the peak hot spot temperature inside coarse FiMX bed exceeds the ignition temperature at input pressures as low as 0.08GPa and large particles lead to large hot-spots and cool slowly due to thermal conduction. For the microfine particle FPVIX, by contrast, the peak hot spot temperature increases only few K and cool rapidly at the same input. For supersonic compaction waves, the effect of compressibility and solid-liquid phase change plays an important role in localized heating. It increases the localization sphere center radius, the dissipated energy induced by compaction andcompression deposits over a larger volume, so that the grain temperature near the contact surface decreased significantly. The long term objective of this research is the study of the effect of particle size and distribution on the compaction behavior of granular energetic materials.