Department d'Enginyeria Qumica, ETSEQ, Universitat Rovira i Virgili, Tarragona, Spain.
Department of Molecular and Mesoscopic Modelling, Institute of Chemical Process Fundamentals of the CAS, Prague, Czech Republic and Department of Physics, Faculty of Science, J. E. Purkinje University, Úst n. Lab., Czech Republic.
Phys Chem Chem Phys. 2019 Dec 7;21(45):24891-24911. doi: 10.1039/c9cp04404c. Epub 2019 Nov 6.
We present a generalised, energy-conserving dissipative particle dynamics (DPDE) method appropriate for the non-isothermal simulation of particle interaction force fields that are both density- and temperature-dependent. A detailed derivation is formulated in a bottom-up manner by considering the thermodynamics of small systems with the appropriate consideration of the fluctuations. Connected to the local volume is a local density and corresponding local pressure, which is determined from an equation-of-state based force field that depends also on a particle temperature. Compared to the original DPDE method, the formulation of the generalised DPDE method requires a change in the independent variable from the particle internal energy to the particle entropy. As part of the re-formulation, the terms dressed particle entropy and the corresponding dressed particle temperature are introduced, which depict the many-body contributions in the local volume. The generalised DPDE method has similarities to the energy form of the smoothed dissipative particle dynamics method, yet fundamental differences exist, which are described in the manuscript. The basic dynamic equations are presented along with practical considerations for implementing the generalised DPDE method, including a numerical integration scheme based on the Shardlow-like splitting algorithm. Demonstrations and validation tests are performed using analytical equation-of-states for the van der Waals and Lennard-Jones fluids. Particle probability distributions are analysed, where excellent agreement with theoretical estimates is demonstrated. As further validation of the generalised DPDE method, both equilibrium and non-equilibrium simulation scenarios are considered, including adiabatic flash heating response and vapour-liquid phase separation.
我们提出了一种通用的、能量守恒的耗散粒子动力学（DPDE）方法，适用于密度和温度相关的粒子相互作用力场的非等温模拟。通过考虑小系统的热力学，并适当考虑波动，以自下而上的方式制定了详细的推导。与局部体积相关联的是局部密度和相应的局部压力，这是由依赖于粒子温度的基于状态方程的力场确定的。与原始 DPDE 方法相比，通用 DPDE 方法的公式要求将独立变量从粒子内能更改为粒子熵。作为重新公式化的一部分，引入了穿衣粒子熵和相应的穿衣粒子温度的概念，它们描述了局部体积中的多体贡献。通用 DPDE 方法与平滑耗散粒子动力学方法的能量形式具有相似性，但存在根本性的差异，本文对此进行了描述。基本的动力学方程与实现通用 DPDE 方法的实际考虑因素一起呈现，包括基于 Shardlow 类似分裂算法的数值积分方案。使用范德华和 Lennard-Jones 流体的分析状态方程进行了演示和验证测试。分析了粒子概率分布，展示了与理论估计的极好一致性。作为通用 DPDE 方法的进一步验证，考虑了平衡和非平衡模拟场景，包括绝热闪蒸加热响应和汽液分相。
