Reducing the effects of compressibility in DPD-based blood flow simulations through severe stenotic microchannels
Reducing the effects of compressibility in DPD-based blood flow simulations through severe stenotic microchannels
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DOI：
10.1016/j.jcp.2017.01.062
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发表时间：
2017-04-15
影响因子：
4.1
通讯作者：
Bluestein, Danny
中科院分区：
文献类型：
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作者：
Gao, Chao;Zhang, Peng;Bluestein, Danny
基于耗散粒子动力学（DPD）的粘性流体流动模拟在流经严重狭窄的几何形状时可能会产生可压缩流动效应。这是由DPD力场中采用的软排斥势引起的，其限制了基于颗粒的流体系统维持大程度压缩的能力。为了缓解这个问题，一个莫尔斯潜力被添加到DPD力场。我们研究了修改后的流体模型（DPD-Morse）的流体特性，并将其与以前发表的传统的DPD流体模型进行了比较。我们的DPD-Morse模型表现出降低的可压缩性，同时保持其他流体性质，如流体密度和粘度。我们进一步研究了严重的3D狭窄微通道与67%狭窄的流体流动特性，使用这两个模型。DPD流体模型沿着流动方向呈现显著的密度梯度，其中流体密度朝向狭窄的上游增加，并且在恢复其初始值之前从狭窄的下游减小。相比之下，DPD-Morse模型证明了沿流动方向沿着更好的均匀流体密度分布。我们比较了两种解决方案与CFD模拟。DPD Morse流体的行为类似于连续流体模型，而DPD流体偏离了它。为了估计两种DPD配方之间的差异可能对血小板活化潜力的影响，我们进一步在流场中嵌入了血小板模型，并研究了剪切应力沿沿着血小板运输轨迹的累积。在狭窄段，DPD流体比DPD-Morse流体表现出更大的应力梯度。DPD流体的血小板转运期较短，因为其产生了较大的流体密度梯度，高估了血小板通过狭窄的加速度。在降低流体可压缩性的情况下，当计算严重狭窄中的血小板活化潜力时，我们的改良的DPD-Morse流体模型比DPD流体模型更准确。(C)2017爱思唯尔公司All rights reserved.
Viscous fluid flow simulations based on dissipative particle dynamics (DPD) may bear compressible flow effects when flowing through severe stenotic geometries. This is caused by the soft repulsive potential employed in the DPD force field, which limits the particle based fluid system ability to sustain a large degree of compression. To mitigate this problem, a Morse potential was added to the DPD force field. We studied the fluid properties of the modified fluid model (DPD-Morse) and compared it with a previously published conventional DPD based fluid model. Our DPD-Morse model demonstrated reduced compressibility while preserving other fluid properties such as the fluid density and viscosity. We further investigated the fluid flow properties for a severe 3D stenotic microchannel with a 67% stenosis, using the two models. The DPD fluid model presented a significant density gradient along the flow direction, where the fluid density increased upstream towards the stenosis and decreased downstream from the stenosis before regaining its initial value. In contrast, the DPD-Morse model demonstrated a far better uniform fluid density distribution along the flow direction. We compared both solutions with CFD simulations. The DPD-Morse fluid resembled the behavior of the continuum fluid model whereas DPD fluid deviated from it. To estimate the effect that the difference between the two DPD formulations may have on the platelet activation potential, we have further embedded a platelet model within the flow field and investigated the shear stress accumulation along the platelet transport trajectory. In the stenotic section, the DPD fluid demonstrated a larger stress gradient than the DPD-Morse fluid. The platelet transport period was shorter for the DPD fluid as it generated a larger fluid density gradient that overestimated the acceleration of the platelet through the stenosis. With reduced fluid compressibility, our modified DPD-Morse fluid model was more accurate than the DPD fluid model when computing the platelet activation potential in a severe stenosis. (C) 2017 Elsevier Inc. All rights reserved.