Investigation of micromixing by acoustically oscillated sharp-edges
Investigation of micromixing by acoustically oscillated sharp-edges
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DOI：
10.1063/1.4946875
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发表时间：
2016-03-01
期刊：
影响因子：
3.2
通讯作者：
Costanzo, Francesco
中科院分区：
文献类型：
--
作者：
Nama, Nitesh;Huang, Po-Hsun;Costanzo, Francesco
最近，声学振荡尖边被用来实现微通道中快速而均匀的混合。在这里，我们提出了一个数值模型来研究存在背景流的锐边微混合器内的声学混合。我们利用微扰分析和广义拉格朗日平均(GLM)理论，结合对流扩散方程，扩展了我们以前报道的数值模型，以包括混合现象。我们将流量变量分为零阶、一阶和二阶变量。这产生了分别表示背景流、声学响应和时间平均流的三组方程。然后依次求解这些方程，得到平均拉格朗日速度，并与对流扩散方程相结合预测浓度分布。通过不同流量下混合指数的实验结果与数值计算结果的比较，验证了数值模型的正确性。进一步，我们利用我们的模型研究了外加输入功率和背景流对基于锐边的微混合器混合性能的影响。我们还建议对之前报道的基于锐边的微混合器进行潜在的设计更改，以提高其性能。最后，我们研究了微沟道内锐边结构的线性排列所产生的可调浓度梯度。由AIP出版公司出版。
Recently, acoustically oscillated sharp-edges have been utilized to achieve rapid and homogeneous mixing in microchannels. Here, we present a numerical model to investigate acoustic mixing inside a sharp-edge-based micromixer in the presence of a background flow. We extend our previously reported numerical model to include the mixing phenomena by using perturbation analysis and the Generalized Lagrangian Mean (GLM) theory in conjunction with the convection-diffusion equation. We divide the flow variables into zeroth-order, first-order, and second-order variables. This results in three sets of equations representing the background flow, acoustic response, and the time-averaged streaming flow, respectively. These equations are then solved successively to obtain the mean Lagrangian velocity which is combined with the convection-diffusion equation to predict the concentration profile. We validate our numerical model via a comparison of the numerical results with the experimentally obtained values of the mixing index for different flow rates. Further, we employ our model to study the effect of the applied input power and the background flow on the mixing performance of the sharp-edge-based micromixer. We also suggest potential design changes to the previously reported sharp-edge-based micromixer to improve its performance. Finally, we investigate the generation of a tunable concentration gradient by a linear arrangement of the sharp-edge structures inside the microchannel. Published by AIP Publishing.