论文标题
离子液体通过非均匀微流体装置的电荷依赖性滑动流动：压落和电动效应
Charge-dependent slip flow of ionic liquids through the non-uniform microfluidic device: pressure drop and electroviscous effects
论文作者
论文摘要
这项工作研究了在稳定的压力驱动层流在对称（1：1）电解质液体的稳定压力驱动层流中，通过均匀充满电的缝隙收缩 - 膨胀（4：1：4）微流体设备的稳定效应。包括Poisson的Nernst-Planck，Navier-Stokes和当前的连续性方程组成的数学模型是使用有限元方法（FEM）来求解的。已经获得了流场（电势，电荷，诱导的电场强度，压降和电动校正系数）并显示了诸如Debye长度（k = 2-20），表面电荷密度（s = 4-16）（s = 4-16）和滑移长度（$ 0 \ le b_0 \ le b_0 \ le b_0 \ le b_0 \ le b_0 \ le 0.20 $）的广泛参数（sc = 1000）（sc sc = 1000）（sc = 1000）（RE = 1000）（RE = 1000）。流场显示了对管理参数的复杂依赖性。与无滑动条件相比，依赖电荷依赖性滑动具有进一步增强的依赖性复杂性。总电势（$ |ΔU| $）最大地增加了78.68％，而压力下降（$ |ΔP| $）在条件范围内最大地减少了63.42％，相对于无滑动流量。在No-Slip（$ b_0 = 0 $）条件下，电动校正系数（$ Y = $ y = $ y =明显的物理粘度比率）增加了33.58％。对于电荷依赖性滑动，它（$ y $）的最大增加比在未防滑流量的情况下增加了72.10％。一个简单的分析模型，可以根据单个均匀切片的Poiseuille流量和由于薄孔造成的压力损失而开发了电流流中压力下降的模型。该模型高估了数值的压力下降2-4％。最后，描绘了数值结果对管理参数的功能依赖性的预测关系，用于在微流体设备的设计和工程中的实际使用。
This work investigates electroviscous effects in presence of charge-dependent slip in steady pressure-driven laminar flow of a symmetric (1:1) electrolyte liquid through a uniformly charged slit contraction - expansion (4:1:4) microfluidic device. The mathematical model comprising Poisson's, Nernst-Planck, Navier-Stokes, and current continuity equations are solved numerically using finite element method (FEM). The flow fields (electrical potential, charge, induced electric field strength, pressure drop, and electroviscous correction factor) have been obtained and presented for a wide range of parameters like inverse Debye length (K=2-20), surface charge density (S=4-16) and slip length ($0\le B_0\le 0.20$) at fixed Schmidt number (Sc=1000) and low Reynolds number (Re=0.01). The flow fields have shown complex dependence on governing parameters. The charge-dependent slip has further enhanced complexity of dependency in comparison to no-slip condition. The total electrical potential ($|ΔU|$) maximally increases by 78.68%, and pressure drop ($|ΔP|$) maximally decreases by 63.42%, relative to no-slip flow, over the ranges of conditions. The electroviscous correction factor ($Y=$ ratio of apparent to physical viscosity) increases by 33.58% under the no-slip ($B_0=0$) condition. It ($Y$) increases maximally by 72.10% for charge-dependent slip than in no-slip flow for considered ranges of the conditions. A simple analytical model to estimate the pressure drop in the electroviscous flow has been developed based on the Poiseuille flow in individual uniform sections and pressure loss due to thin orifice. The model overpredicts pressure drop by 2 - 4% from the numerical values. Finally, the predictive relations, depicting the functional dependence of numerical results on governing parameters, are presented for their practical use in design and engineering of microfluidic devices.
