Department of Molecular and Mesoscopic Modelling, Institute of Chemical Process Fundamentals of the CAS, Prague, Czech Republic.
Weapons and Materials Research Directorate, U.S. Army Combat Capabilities Development Command Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005-5066, USA.
J Chem Phys. 2019 Sep 21;151(11):114112. doi: 10.1063/1.5117904.
We present a general, flexible framework for a constant-energy variant of the dissipative particle dynamics method that allows chemical reactions (DPD-RX). In our DPD-RX approach, reaction progress variables are assigned to each particle that monitor the time evolution of an extent-of-reaction associated with the prescribed reaction mechanisms and kinetics assumed to occur within the particle, where chemistry can be modeled using complex or reduced reaction mechanisms. We demonstrate our DPD-RX method by considering thermally initiated unimolecular decomposition of the energetic material, cyclotrimethylene trinitramine (RDX), into a molecular gas mixture. Studies are performed to demonstrate the effect of a spatially averaged particle internal temperature and a local reaction volume term in the chemical kinetics expressions, where both provide implicit mechanisms for capturing condensed phase reactivity. We also present an analysis of the expansion of the product gas mixture during decomposition. Finally, a discussion of other potential applications and extensions of the DPD-RX method is given.
我们提出了一种用于耗散粒子动力学方法的恒能量变体的通用、灵活的框架，该方法允许进行化学反应（DPD-RX）。在我们的 DPD-RX 方法中，反应进度变量被分配给每个粒子，这些变量监测与规定的反应机制相关的反应程度的时间演化，这些反应机制和动力学被假设在粒子内发生，其中可以使用复杂或简化的反应机制来模拟化学。我们通过考虑热引发的高能材料，环三亚甲基三硝胺（RDX），分解成分子气体混合物，来演示我们的 DPD-RX 方法。研究表明，粒子内部温度的空间平均和化学动力学表达式中的局部反应体积项对反应的影响，这两者都为捕捉凝聚相反应性提供了隐含机制。我们还对分解过程中产物气体混合物的膨胀进行了分析。最后，讨论了 DPD-RX 方法的其他潜在应用和扩展。
