Abstract
As an extension of our previous study, the flow and mixing characteristics of a serpentine mixer in non-creeping flow conditions are investigated numerically. A periodic velocity field is obtained for each spatially periodic channel with the Reynolds number (Re) ranging from 0.1 to 70 and the channel aspect ratio from 0.25 to one. The flow kinematics is visualized by plotting the manifold of the deforming interface between two fluids. The progress of mixing affected by the Reynolds number and the channel geometry is characterized by a measure of mixing, the intensity of segregation, calculated using the concentration distribution. A mixer with a lower aspect ratio, which is a poor mixer in the creeping flow regime, turns out to be an efficient one above a threshold value of the Reynolds number, Re = 50. This is due to the combined effect of the enhanced rotational motion of fluid particles and back flows near the bends of the channel driven by inertia. As for a mixer with a higher aspect ratio, the intensity of segregation has its maximum around Re = 30, implying that inertia does not always have a positive influence on mixing in this mixer.
Highlights
In microfluidic systems that integrate laboratory functions on a single chip using extremely small liquid volumes in either biology or chemistry, mixing is one of the key tasks in determining the overall success of the system [1,2,3,4]
According to the theory of the linked twist maps (LTMs) [10], a necessary condition for chaos is the crossing of streamlines, which should occur at different times in a two-dimensional time-periodic flow
We numerically investigated the flow and mixing characteristics of the chaotic serpentine mixer (CSM) in non-creep flow conditions
Summary
In microfluidic systems that integrate laboratory functions on a single chip using extremely small liquid volumes in either biology or chemistry, mixing is one of the key tasks in determining the overall success of the system [1,2,3,4]. The typical diffusion time scale td is represented by td ∼ l2 /D, where l is the characteristic length and D the coefficient of molecular diffusion To overcome such difficulties, chaotic advection [7,8,9,10], which has been successfully applied to the development of macroscale mixers working in the laminar flow regime, were adopted in micromixers [11,12,13,14]. As an extension to our previous work [25], in this study, the effect of inertia on the fluid flow and the mixing performance of the CSM will be examined using a Reynolds number ranging from 0.1 to 70. The progress of mixing in a mixer geometry is characterized using a measured of mixing, called the intensity of segregation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
