耗散粒子动力学处理复杂固体壁面的一种有效方法

耗散粒子动力学(dissipative particle dynamics,DPD)作为一种介观尺度拉格朗日型粒子方法,已经成功地应用于微纳米流动和生化科技的研究中.复杂固体壁面的处理和壁面边界条件的实施一直是DPD方法发展及应用的一个障碍.提出了处理复杂固体壁面的一种新的方法.复杂固体区域通过冻结随机分布并且达到平衡状态的DPD粒子代表;所冻结的DPD粒子位于临近流动区域的一个截距内;在靠近固体壁面的流动区域中设置流动反弹层,当流动DPD粒子进入此流动层后反弹回流动区域.应用这种固体壁面处理方法对简单流动区域的Poiseuille流动和复杂多孔介质内的流动进行了分析.研究表明,这种新的固体壁面处理方法能够有效模拟复杂固体区域,准确实施壁面边界条件.

A new boundary treatment algorithm for dissipative particle dynamics

Dissipative particle dynamics (DPD) is a meso-scale, Lagrangian particle method, and has been successfully applied to different areas including micro- and nano-fluidics, bio- and chemical technologies. The treatment of solid matrix and the implementation of solid boundary conditions have been an important task for the development and application of the DPD method. This paper presents a new method of treating complex solid boundary. Solid grains in complex flow geometry can be represented by freezing randomly distributed DPD particles which have reached an equilibrium state. To increase computational efficiency, only the boundary DPD particles within one cut-off distance from the flow region are frozen. A thin layer in the flow region next to the solid boundary is used to bounce mobile DPD particles in this layer back to the flow region. The DPD method and this new boundary treatment algorithm are used to model the Poiseuille flow and a flow problem in a complex porous media. It is demonstrated that this new boundary treatment algorithm can effectively model complex solid matrix and correctly implement non-slip boundary condition.