高分子液滴碰撞的耗散粒子动力学模拟

Simulation of Polymer Drop Collision By Dissipative Particle Dynamics

利用耗散粒子动力学模拟了剪切流中两个变形的高分子液滴相互碰撞过程.高分子液滴由多根有限拉伸非线性弹性珠簧链(FENE链)构成.研究了碰撞分离和碰撞聚合两种情形.讨论了由于剪切流导致的液滴自扩散现象.除了Ca与粘性比之外,液滴之间的界面张力系数对于两个液滴碰撞后聚合或者分离过程有重要的影响.当液滴之间存在界面张力,一定条件下可形成复合液滴.剪切流条件下,组成复合液滴的两个子液滴会出现相互翻滚现象.

The collision process of two deformed polymer drops undergoing a shear flow was simulated by using dissipative particle dynamics （DPD）.The polymer drop is made up of many finite extensible non-linear elastic （FENE） bead spring chains.Both separating collision and coalescence collision were considered.The shear-induced anisotropic self-diffusion phenomenon of drops was studied.Besides capillary number（Ca） and viscosity ratio,the interfacial tension between two drops plays an important role in the coalescence collision or separation collision of the two drops.Due to the non-zero surface tension between two drops,a compound drop could be formed under certain conditions,and the compound drop tumbles in simple shear flow.