Physical mechanisms relevant to flow resistance in textured microchannels
Physical mechanisms relevant to flow resistance in textured microchannels
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与纹理微通道中的流动阻力相关的物理机制
DOI：
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发表时间：
2017
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通讯作者：
D. Papageorgiou
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作者：
Simon Game;M. Hodes;E. Keaveny;D. Papageorgiou
通过用与含有惰性气体的纵向凹槽相邻的边界代替平坦的无滑动边界，可以减少流过微通道的液体的流动阻力，从而导致明显的滑动。随着这种纹理化微通道在微流体系统和微电子直接液体冷却等领域的应用，需要可用于设计和优化的预测数学模型。在这项工作中，我们描述了一个模型，它结合了气体粘度（界面剪切），弯月面突起（到凹槽）和通道的纵横比的物理效应，并显示如何生成精确的解决方案，层流场使用切比雪夫配置和区域分解数值方法。虽然这些影响的耦合往往被忽略从其他模型，我们表明，它起着重要的作用，在这种流动的行为。我们发现，例如，气体粘度的存在可能会导致弯月面突出对流速产生比以前认识到的更负面的影响。事实上，我们表明，有通道的几何形状，其中弯月面突起增加了气体粘度的情况下的流速，并降低它在气体粘度的存在下。在这项工作中，我们选择了一个特定的定义通道高度：从一个凹槽的底部到相对凹槽的底部的距离。实际上，这种通道用于受约束的几何形状，因此具有与该定义一致的规定高度。这种选择使我们能够轻松地在纹理通道和占据相同空间的无滑动通道之间进行有意义的比较。电子邮件地址：imperial.ac.uk
Flow resistance of liquids flowing through microchannels can be reduced by replacing flat, noslip boundaries with boundaries adjacent to longitudinal grooves containing an inert gas, resulting in apparent slip. With applications of such textured microchannels in areas such as microfluidic systems and direct liquid cooling of microelectronics, there is a need for predictive mathematical models that can be used for design and optimization. In this work, we describe a model that incorporates the physical effects of gas viscosity (interfacial shear), meniscus protrusion (into the grooves) and channel aspect ratio and show how to generate accurate solutions for the laminar flow field using Chebyshev collocation and domain decomposition numerical methods. While the coupling of these effects are often omitted from other models, we show that it plays a significant role in the behavior of such flows. We find that, for example, the presence of gas viscosity may cause meniscus protrusion to have a more negative impact on the flow rate than previously appreciated. Indeed, we show that there are channel geometries for which meniscus protrusion increases the flow rate in the absence of gas viscosity and decreases it in the presence of gas viscosity. In this work, we choose a particular definition of channel height: the distance from the base of one groove to the base of the opposite groove. Practically, such channels are used in constrained geometries and therefore are of prescribed heights consistent with this definition. This choice allows us to easily make meaningful comparisons between textured channels and no-slip channels occupying the same space. ∗ Email address for correspondence: s.game14@imperial.ac.uk