Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates.
Department of Aerospace Engineering, Khalifa University of Science and Technology, Abu Dhabi 127788, United Arab Emirates.
J Chem Phys. 2019 Feb 7;150(5):054901. doi: 10.1063/1.5079835.
We have used a dissipative particle dynamics (DPD) model to study the movement of microparticles in a microfluidic device at extremely low Reynolds number (Re). The particles, immersed in a medium, are transported in the microchannel by a flow force and deflected transversely by an external force along the way. An in-house Fortran code is developed to simulate a two-dimensional fluid flow using DPD at Re ≥ 0.0005, which is two orders of magnitude less than the minimum Re value previously reported in the DPD literature. The DPD flow profile is verified by comparing it with the exact solution of Hagen-Poiseuille flow. A bioparticle based on a rigid spring-bead model is introduced in the DPD fluid, and the employed model is verified via comparing the velocity profile past a stationary infinite cylinder against the profile obtained via the finite element method. Moreover, the drag force and drag coefficient on the stationary cylinder are also computed and compared with the reported literature results. Dielectrophoresis (DEP) is investigated as a case study for the proposed DPD model to compute the trajectories of red blood cells in a microfluidic device. A mapping mechanism to scale the external deflecting force from the physical to DPD domain is performed. We designed and built our own experimental setup with the aim to compare the experimental trajectories of cells in a microfluidic device to validate our DPD model. These experimental results are used to investigate the dependence of the trajectory results on the Reynolds number and the Schmidt number. The numerical results agree well with the experiment results, and it is found that the Schmidt number is not a significant parameter for the current application; Reynolds numbers combined with the DEP-to-drag force ratio are the only important parameters influencing the behavior of particles inside the microchannel.
我们使用耗散粒子动力学（DPD）模型研究了在极低雷诺数（Re）下微流控装置中微颗粒的运动。颗粒沉浸在介质中，通过流体力在微通道中输送，并在沿途中被外力横向偏转。开发了一个内部 Fortran 代码，用于在 Re≥0.0005 时使用 DPD 模拟二维流体流动，这比以前在 DPD 文献中报道的最小 Re 值低两个数量级。通过将 DPD 流型与 Hagen-Poiseuille 流的精确解进行比较，验证了 DPD 流型。在 DPD 流体中引入了基于刚性弹簧珠模型的生物颗粒，通过将经过静止无限圆柱的速度分布与通过有限元方法获得的速度分布进行比较，验证了所采用的模型。此外，还计算了静止圆柱上的阻力和阻力系数，并与文献报道的结果进行了比较。以介电泳（DEP）为例研究了所提出的 DPD 模型，以计算微流控装置中红细胞的轨迹。执行了一种将外部偏转力从物理域映射到 DPD 域的映射机制。我们设计并建立了自己的实验装置，目的是将细胞在微流控装置中的实验轨迹与我们的 DPD 模型进行比较，以验证我们的模型。这些实验结果用于研究轨迹结果对雷诺数和施密特数的依赖性。数值结果与实验结果吻合良好，发现施密特数不是当前应用的重要参数；雷诺数与 DEP 到阻力的比值是影响微通道内颗粒行为的唯一重要参数。
