Maddala Jeevan, Vanapalli Siva A, Rengaswamy Raghunathan
Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79401-3121, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Feb;89(2):023015. doi: 10.1103/PhysRevE.89.023015. Epub 2014 Feb 26.
Droplets moving in a microfluidic loop device exhibit both periodic and chaotic behaviors based on the inlet droplet spacing. We observe that the periodic behavior is an outcome of carrier phase mass conservation principle, which translates into a droplet spacing quantization rule. This rule implies that the summation of exit spacing is equal to an integral multiple of inlet spacing. This principle also enables identification of periodicity in experimental systems with input scatter. We find that the origin of chaotic behavior is through intermittency, which arises when drops enter and leave the junctions at the same time. We derive an analytical expression to estimate the occurrence of these chaotic regions as a function of system parameters. We provide experimental, simulation, and analytical results to validate the origin of periodic and chaotic behavior.
在微流体循环装置中移动的液滴，根据入口液滴间距会呈现出周期性和混沌行为。我们观察到，周期性行为是载流相质量守恒原理的结果，这转化为液滴间距量化规则。该规则意味着出口间距的总和等于入口间距的整数倍。这一原理还能够识别具有输入散射的实验系统中的周期性。我们发现混沌行为的起源是通过间歇性产生的，当液滴同时进入和离开节点时就会出现这种情况。我们推导了一个解析表达式，以估计这些混沌区域的出现情况作为系统参数的函数。我们提供了实验、模拟和分析结果，以验证周期性和混沌行为的起源。
