论文标题
微通道中的珠子,气泡和下降:中心位置和平衡速度的稳定性
Beads, bubbles and drops in microchannels: stability of centered position and equilibrium velocity
论文作者
论文摘要
在许多天然,工业和技术情况下,了解和预测微流体中分散的微观对象的动态至关重要。在本文中,我们通过实验表征了平衡速度$ v $和横向位置$ \ varepsilon $在各种分散的微型物体中,例如珠子,气泡和滴滴,在圆柱形微通道中,在空中范围内的广泛参数范围内。通过系统地改变无量纲的对象大小($ d \ in [0.1; 1] $),粘度比($λ\ in [10^{ - 2}; \ infty [$),密度比($φ\ in [10^{ - 3}; 2] $)以及毛细血管数($ \ text {ca} \ in [10^{ - 3}; 0.3] $),我们提供一项一项一项一项一项一项一项一项探讨从不可衍射的粘性体制到可变形的Visco Entrotio-capillary策略的各种动态,从而强调唯一和综合惯性和capillation capillation和Capillation的角色,并将其迁移到后来的效果上。将实验与稳定的3D Navier-Stokes模型进行了比较,并对不可压缩的两相流体进行了很好的处理,包括惯性的影响和可能的界面变形。该模型使实验可以合理化,并就问题的主要参数的影响提供详尽的参数分析,主要是在两个方面:中心位置的稳定性和分散对象的速度。有趣的是,我们提出了对象速度$ v $作为$ d $,$ \ varepsilon $和$λ$的函数的有用相关性,该功能是在$ \ text {re} = \ text {ca} = 0 $ limit中获得的,但实际上对$ \ \ text {re} $和$ \ text lin lin line and line and line and line实际上有效,但实际上有效。
Understand and predict the dynamics of dispersed micro-objects in microfluidics is crucial in numerous natural, industrial and technological situations. In this paper, we experimentally characterized the equilibrium velocity $V$ and lateral position $\varepsilon$ of various dispersed micro-objects such as beads, bubbles and drops, in a cylindrical microchannel over an unprecedent wide range of parameters. By systematically varying the dimensionless object size ($d \in [0.1; 1]$), the viscosity ratio ($λ\in [10^{-2}; \infty[$), the density ratio ($φ\in [10^{-3}; 2]$), the Reynolds number ($\Re \in [10^{-2}; 10^2]$), and the capillary number ($\text{Ca} \in [10^{-3}; 0.3]$), we offer a general study exploring various dynamics from the nonderformable viscous regime to the deformable visco-inertio-capillary regime, thus enabling to highlight the sole and combined roles of inertia and capillary effects on lateral migration. The experiments are compared and well-agree with a steady 3D Navier-Stokes model for incompressible two-phase fluids including both the effects of inertia and possible interfacial deformations. This model enables to rationalize the experiments and to provide an exhaustive parametric analysis on the influence of the main parameters of the problem, mainly on two aspects: the stability of the centered position and the velocity of the dispersed object. Interestingly, we propose a useful correlation for the object velocity $V$ as functions of the $d$, $\varepsilon$ and $λ$, obtained in the $\text{Re}=\text{Ca}=0$ limit, but actually valid for a larger range of values of $\text{Re}$ and $\text{Ca}$ in the linear regimes.