In this work, the inertial focusing of a microparticle in spiral channels is investigated numerically using a numerical solver developed in the framework of OpenFOAM open-source software. A special periodic boundary condition was implemented for a developed immersed boundary method to mimic the long microchannel, along with an adaptive meshing procedure to significantly reduce memory resources and shorten computation time. Simulation of a microparticle moving inside a square duct confirmed the existence of eight equilibrium positions over the channel’s cross section, four of which are located close to the channel wall centers, whereas the others are positioned near the corners, which has been reported in many studies before. Most importantly, we present, for the first time, a direct numerical simulation for the inertial sorting phenomenon of a microparticle in the spiral channel of rectangular and trapezoidal cross sections. Comprehensive analysis of the resulting lateral force field maps and Dean vortex configurations provides more insight into the focusing mechanism of a microparticle, which is beneficial for the design and optimization of cell separation microfluidic devices.

中文翻译：

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螺旋微通道中微粒惯性聚焦的数值模型研究

在这项工作中，使用在OpenFOAM开源软件框架内开发的数值求解器，对螺旋通道中微粒的惯性聚焦进行了数值研究。针对开发的沉浸式边界方法（模仿长微通道）实施了特殊的周期性边界条件，并采用了自适应网格划分程序来显着减少内存资源并缩短了计算时间。微粒在方管内运动的模拟证实了通道横截面上存在八个平衡位置，其中四个位置靠近通道壁中心，而其他位置则位于拐角附近，这在许多研究中已有报道。之前。最重要的是，我们第一次展示 矩形和梯形截面螺旋通道中微粒惯性分选现象的直接数值模拟。对产生的侧向力场图和Dean涡旋构型的综合分析可提供对微粒聚焦机制的更多见解，这对于设计和优化细胞分离微流控装置非常有用。