Modeling The Effects of Shock Pressure and Pore Morphology on Hot Spot Mechanisms in HMX
Modeling The Effects of Shock Pressure and Pore Morphology on Hot Spot Mechanisms in HMX
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DOI：
10.1002/prep.201800082
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发表时间：
2018-06
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影响因子：
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通讯作者：
H. Springer;S. Bastea;A. Nichols;C. Tarver;J. Reaugh
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作者：
H. Springer;S. Bastea;A. Nichols;C. Tarver;J. Reaugh
研究了冲击压力和孔形态对HMX（octahydro-1，3，5，7-tetranitro-1，3，5，7-tetrazocine）中热点形成和生长的影响。在这些研究中使用了非反应性和反应性ALE 3D模拟。我们的非反应性模拟显示，在较低的冲击压力（2-10 GPa）下，由于剪切带的形成，粘性占主导地位的孔隙坍塌模式，以及在较高的冲击压力（20 - 40 GPa）下，由于大量熔化，流体动力学占主导地位的模式。 当通过体冲击加热归一化时，粘性主导的孔隙塌陷模式在产生热点方面更有效。对于固定的孔隙面积和冲击压力，孔隙形态影响塌陷后的温度分布和反应速率。我们发现粘结剂-晶粒界面处的多个表面孔隙往往反应最快。由于它们在HMX颗粒中的上游位置，表面孔比内部孔更快地塌陷;因此，反应的程度通常有利于这些形态，因为它们有更多的时间生长。一般来说，多个较小的热点往往比单个较大的热点反应更快，因为它们会加速彼此的燃烧。然而，对于非反应性和反应性模拟，形态效应的等级顺序并不相同。例如，虽然多个表面孔产生最高的反应速率，但它们不会产生最高的（非反应性）热点温度。我们的数值研究提供的热点机制代替直接测量的见解，并可用于开发先进的冲击起爆模型。
We investigate the effects of shock pressure and pore morphology on the formation and growth of hot spots in HMX (octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine). Both non‐reactive and reactive ALE3D simulations are used in these studies. Our non‐reactive simulations show a viscous‐dominated pore collapse mode at lower shock pressures (2–10 GPa) with shear band formation and a hydrodynamic‐dominated mode at higher shock pressures (20‐40 GPa) due to bulk melting. When normalized by bulk shock heating, viscous‐dominated pore collapse modes are more efficient at generating hot spots. Pore morphology influences the post‐collapse temperature distributions and reaction rate for a fixed pore area and shock pressure. We find that multiple surface pores at the binder‐grain interface tend to react the fastest. Due to their upstream location in the HMX grain, the surface pores collapse sooner than interior pores; thus, the extent of reaction will generally favor these morphologies because they have more time to grow. In general, multiple smaller hot spots tend to react faster than a single larger hot spot because they accelerate one another's burning. The rank order of morphology effects, however, is not the same for non‐reactive and reactive simulations. For example, while multiple surface pores produce the highest reaction rates they do not produce the highest (non‐reactive) hot spot temperatures. Our numerical studies provide insights on hot spot mechanisms in lieu of direct measurements and can be used to develop advanced shock initiation models.