System-level simulation of liquid filling in microfluidic chips.
System-level simulation of liquid filling in microfluidic chips.
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DOI：
10.1063/1.3589843
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发表时间：
2011-05
期刊：
影响因子：
3.2
通讯作者：
Hongjun Song;Yi Wang;K. Pant
中科院分区：
文献类型：
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作者：
Hongjun Song;Yi Wang;K. Pant
微流体通道中的液体填充是一个复杂的过程，其取决于各种几何、操作和材料参数，诸如微通道几何形状、流速、压力、液体表面张力和通道表面的接触角。对填充过程的准确分析可以提供对填充时间、气泡捕获和死区形成的关键见解，并有助于评估各种设计参数之间的权衡，从而实现最佳芯片设计。然而，复杂微流体网络中液体填充的有效建模仍然是一个重大挑战。从计算的角度来看，高保真计算方法，如流体体积法，是非常昂贵的。另一方面，分析模型主要适用于理想化的几何形状，因此无法准确捕获复杂微流体系统的芯片级行为。本文提出了一个参数化的动态模型，用于三维微流控网络中液体填充的系统级分析。在我们的方法中，一个复杂的微流体网络被解构成一组常用的组件，如水库，微通道和路口。然后根据其空间布局和操作原理组装组件，以实现快速的系统级模型。基于瞬态动量方程建立了微通道内液体前沿的动态模型。在交界处的质量守恒的原则是用来连接的微通道中的流体参数从交界处发出。这些组件模型的组合产生一组微分和代数方程，其在积分时提供液体填充过程的时间信息，特别是液体前沿传播（即，到达时间）。该模型被用来模拟瞬态液体填充过程中的各种微流体结构和多路复用器，代表一个复杂的微流体网络。通过与3D高保真数值研究的比较，验证了我们的系统级模型的精度（相对误差小于7%）和数量级的加速比（30 000 X-4 000 000 X）。我们的研究结果清楚地建立了我们的模型和模拟方法的实用性，用于快速，可靠地分析液体填充，以指导复杂微流体网络的设计优化。
Liquid filling in microfluidic channels is a complex process that depends on a variety of geometric, operating, and material parameters such as microchannel geometry, flow velocity∕pressure, liquid surface tension, and contact angle of channel surface. Accurate analysis of the filling process can provide key insights into the filling time, air bubble trapping, and dead zone formation, and help evaluate trade-offs among the various design parameters and lead to optimal chip design. However, efficient modeling of liquid filling in complex microfluidic networks continues to be a significant challenge. High-fidelity computational methods, such as the volume of fluid method, are prohibitively expensive from a computational standpoint. Analytical models, on the other hand, are primarily applicable to idealized geometries and, hence, are unable to accurately capture chip level behavior of complex microfluidic systems. This paper presents a parametrized dynamic model for the system-level analysis of liquid filling in three-dimensional (3D) microfluidic networks. In our approach, a complex microfluidic network is deconstructed into a set of commonly used components, such as reservoirs, microchannels, and junctions. The components are then assembled according to their spatial layout and operating rationale to achieve a rapid system-level model. A dynamic model based on the transient momentum equation is developed to track the liquid front in the microchannels. The principle of mass conservation at the junction is used to link the fluidic parameters in the microchannels emanating from the junction. Assembly of these component models yields a set of differential and algebraic equations, which upon integration provides temporal information of the liquid filling process, particularly liquid front propagation (i.e., the arrival time). The models are used to simulate the transient liquid filling process in a variety of microfluidic constructs and in a multiplexer, representing a complex microfluidic network. The accuracy (relative error less than 7%) and orders-of-magnitude speedup (30 000X-4 000 000X) of our system-level models are verified by comparison against 3D high-fidelity numerical studies. Our findings clearly establish the utility of our models and simulation methodology for fast, reliable analysis of liquid filling to guide the design optimization of complex microfluidic networks.