AI 中文总结
开发粒子模拟方法，预测长球棒稠密悬浮液的粘度与微观结构，验证实验数据，为该类材料的流体力学等研究提供工具。
AI 中文摘要
杆状颗粒稠密悬浮液广泛存在于自然界与工业制造中，其流体力学特性至关重要。我们开发了一种粒子模拟方法，用于模拟该类悬浮液在简单剪切流中的行为，可针对给定的固体体积分数和颗粒长径比预测其粘度与微观结构。该模型追踪长球棒在短程摩擦接触力与流体动力作用下的运动轨迹，其灵感来源于已为球形颗粒悬浮液研究提供新见解的同类工具；模型融入了长球棒间润滑力计算的新方案及时间步长的动态确定方法。对于长径比达20的情况，模型预测剪切启动时会出现粘度峰值，随后进入稳态，且稳态粘度随体积分数与长径比的增加而系统性上升；同时，颗粒取向随体积分数增加而增强，直至达到与长径比相关的临界点。我们的模型验证了已有的有限的颗粒状杆悬浮液流变学实验数据，为深入探究这类广泛存在材料的流体力学、微观结构及流变学提供了工具。
英文摘要
Dense suspensions of rod-shaped granular particles are widespread in nature and manufacturing, where their fluid mechanical properties are often paramount. We have developed a particle-based simulation that models such suspensions under simple shear flow, providing predictions of the viscosity and microstructure for a given solids volume fraction and particle aspect ratio. The model tracks the trajectories of spherocylindrical rods under the action of short-range frictional contact and hydrodynamic forces, inspired by similar tools that have generated new insight into suspensions of granular spheres. It incorporates new schemes for the computation of lubrication forces between spherocylinders and the dynamic determination of the timestep. For aspect ratios up to 20, the model predicts a viscosity spike at shear start-up, giving way to steady state viscosities that increase systematically with volume fraction and aspect ratio. Likewise, particle alignment increases with volume fraction up to an aspect-ratio-dependent critical point. Our model corroborates the limited experimental rheology data available for suspensions of granular rods, and offers a tool for fundamental exploration of the fluid mechanics, microstructure and rheology of this widespread material.
Comments27 pages, 6 figures
