In this paper, a numerical study of a chaotic mixing process that involves a highly viscous fluid is presented. The investigated mixer is composed of two circular rods maintained vertically inside a cylindrical tank. The tank and the rods are heated and can rotate around their revolution axis. Chaotic flows are obtained by imposing a temporal modulation of the rotational velocity. Unsteady equa...

A novel micromixer which utilizes chaotic mixing induced by ferrofluid actuation is developed. The micromixer is fabricated by a polydimethylsiloxane micromolding technique. The micromixer consists of a T-shaped main mixing channel and two parallel sub-channels that intersect the main channel. Oscillation of a couple of ferrofluid slugs in the sub-channels, induced by external permanent magnet ...

This paper proposes a new "twisted" 3D microfluidic mixer fabricated by a laser writing/microfabrication technique. Effective and efficient mixing using the twisted micromixers can be obtained by combining two general chaotic mixing mechanisms: splitting/recombining and chaotic advection. The lamination of mixer units provides the splitting and recombination mechanism when the quadrant of circl...

Laminar flow and mixing of a Newtonian fluid are characterized in a four-element Koch-Glitsch SMX static mixer. The computational analysis on a fine, unstructured mesh containing more than 3.5 million tetrahedral elements led to high-resolution numerical data for ®elocity and pressure. Computed pressure drops agreed excellently with those in the literature. The flow in this static mixer is esse...

We conducted a numerical study on mixing in a barrier embedded micromixer with an emphasis on the effect of periodic and aperiodic sequences of mixing protocols on mixing performance. A mapping method was employed to investigate mixing in various sequences, enabling us to qualitatively observe the progress of mixing and also to quantify both the rate and the final state of mixing. First, we int...

An active inline mixer, called Rotating Arc-Wall mixer (RAW), suitable for flows at low Reynolds number and high P\'eclet number, is studied. The forcing protocol, imposed by three rotating circular arc-walls, time periodic. We use simple phenomenological arguments to estimate heuristically the mixing efficiency with two nondimensional control parameters: frequency of strength cross flow relati...

We consider the mixing of similar, cohesionless granular materials in quasi-two-dimensional rotating containers by means of theory and experiment. A mathematical model is presented for the flow in containers of arbitrary shape but which are symmetric with respect to rotation by 180 degrees and half-filled with solids. The flow comprises a thin cascading layer at the flat free surface, and a fix...

The objective of the present work is to describe a new mapping tool using anisotropic unstructured meshes to study mixing within a spatially periodic pipe %ow. Instead of tracking the boundaries of elementary cell %ow domains as it was done in the original mapping method established by Kruijt et al. (A.I.Ch.E. J. 47 (5) (2001a) 1005; Int. Polym. Process. 16 (2) (2001b) 151) and Galaktionov et a...

In this work, we proposed a novel design of microfluidic mixer utilizing the amplified Marangoni chaotic advection induced by AC continuous electrowetting of a metal droplet situated in electrolyte solution, due to the linear and quadratic voltage-dependence of flow velocity at small or large voltages, respectively. Unlike previous researchers exploiting the unidirectional surface stress with D...

Rapid freeze-quench (RFQ) trapping of short-lived reaction intermediates for spectroscopic study plays an important role in the characterization of biological reactions. Recently there has been considerable effort to achieve submillisecond reaction deadtimes. We present here a new, robust, high-velocity microfluidic mixer that enables such rapid freeze-quenching. It is a based on the mixing met...