Simulation of aggregating particles in complex flows by the lattice kinetic Monte Carlo method
Simulation of aggregating particles in complex flows by the lattice kinetic Monte Carlo method
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DOI：
10.1063/1.3521395
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发表时间：
2011-01-21
影响因子：
4.4
通讯作者：
Diamond, Scott L.
中科院分区：
文献类型：
--
作者：
Flamm, Matthew H.;Sinno, Talid;Diamond, Scott L.
我们开发并验证了一个有效的晶格动力学蒙特卡罗（LKMC）方法模拟粒子聚集在层流空间变化的剪切速率，如抛物线流或流动与驻涡。开发了接触时间模型来描述作为局部剪切速率G和接近角θ的函数的颗粒-颗粒碰撞效率。该模型有效地解释了接近粒子之间的流体动力学相互作用，这在LKMC框架中没有明确考虑。对于不完全碰撞，推导出的碰撞效率[π = 1 - integral（pi/2）（0）sin theta exp（-2cot theta Gamma（agg）/G）d theta]被发现仅取决于Gamma（agg）/G，其中Gamma（agg）是指定的聚集速率。对于管流中聚集的血小板，Gamma（agg）= 0.683 s（-1）预测了生理范围内（G = 40-1000 s（-1））的实验测量e，并且与alpha（2b）beta（3）-纤维蛋白原键动力学一致。聚集在抛物线流导致最大的聚集体形成的剪切速率和停留时间是最大的壁附近，然而，中间区域之间的壁和中心表现出最高的聚集率，由于耗尽的反应物最接近的壁。然后，出于狭窄或瓣膜流动，我们采用LKMC模拟这里开发的挡板的几何形状，表现出区域的挤压流和常设回流区。在这些计算中，最大的聚集体形成在涡流内（最大停留时间），而挤压流区域对应于聚集速率最高的区域。(C)2011年美国物理学会。[doi：10.1063/1.3521395]
We develop and validate an efficient lattice kinetic Monte Carlo (LKMC) method for simulating particle aggregation in laminar flows with spatially varying shear rate, such as parabolic flow or flows with standing vortices. A contact time model was developed to describe the particle-particle collision efficiency as a function of the local shear rate, G, and approach angle, theta. This model effectively accounts for the hydrodynamic interactions between approaching particles, which is not explicitly considered in the LKMC framework. For imperfect collisions, the derived collision efficiency [epsilon = 1 - integral(pi/2)(0) sin theta exp(-2cot theta Gamma(agg)/G)d theta] was found to depend only on Gamma(agg)/G, where Gamma(agg) is the specified aggregation rate. For aggregating platelets in tube flow, Gamma(agg) = 0.683 s(-1) predicts the experimentally measured e across a physiological range (G = 40-1000 s(-1)) and is consistent with alpha(2b)beta(3)-fibrinogen bond dynamics. Aggregation in parabolic flow resulted in the largest aggregates forming near the wall where shear rate and residence time were maximal, however intermediate regions between the wall and the center exhibited the highest aggregation rate due to depletion of reactants nearest the wall. Then, motivated by stenotic or valvular flows, we employed the LKMC simulation developed here for baffled geometries that exhibit regions of squeezing flow and standing recirculation zones. In these calculations, the largest aggregates were formed within the vortices (maximal residence time), while squeezing flow regions corresponded to zones of highest aggregation rate. (C) 2011 American Institute of Physics. [doi:10.1063/1.3521395]