Quantitative characterization of micromixing simulation

Abstract

Micromixers with floor-grooved microfluidic channels have been successfully demonstrated in experiment. In this work, we numerically simulated the mixing within the devices and used the obtained concentration versus channel length profiles to quantitatively characterize the process. It was found that the concentration at any given cross-section location of the microfluidic channel periodically oscillates along the channel length, in coordination with the groove-caused helical flow during the mixing, and eventually converges to the neutral concentration value of two the mixing fluids. With these data, the specific channel length required for each helical flow to complete, the mixing efficiency of the devices, and the total channel length required to complete a mixing were easily defined and quantified, and were used to directly and comprehensively characterize the micromixing. This concentration versus channel length profile-based characterization method was also demonstrated in quantitatively analyzing the micromixing within a classic T mixer. It has clear advantages over the traditional concentration image-based characterization method that is only able to provide qualitative or semiquantitative information about a micromixing, and is expected to find an increasing use in studying mixing and optimizing device structure through numerical simulations.

A simplified design of the staggered herringbone micromixer for practical applications

“…This L m value is much smaller than 5.0 mm, which was needed in a SGM under similar flow conditions. 34 This conclusion is in good agreement with the reported observations that SHM is more effective than SGM due to the formation of two helical flows in the mixing process. 8,20 …”

“…34 This was used to gain insights into the dynamic micromixing process within a SHM since concentration change is related to both vortices and mixing occurs along channel length. In comparison with the commonly used color coded cross-sectional concentration profiles, as shown in Fig.…”

Evaluation of Floor-grooved Micromixers using Concentration-channel Length Profiles

“…As generally discussed in the literature, a helical flow is created inside the microchannel of SGM due to a down-channel flow component as well as transversely rotational flow component [10,19,30]. All concentration profiles of SGM, as seen in Figures 3(a), (c) and (e), showed that the concentrations oscillated along the channel length as the two mixing fluids travelled helically and mixed along the channel length.…”

“…However, mixers for DEP-based microcencentrator aimed at circulating particles, instead of mixing two particle populations. In a previous study, we proposed to use a concentration profile vs. channel length method to characterize and analyze micromixing in SGM [30]. We showed that this new method provided specific quantitative data to directly characterize the performance of a mixer of interest.…”

Study on the fluid dynamics of nitrogen and hydrogen gases subjected to wires element in monolithic channel

“…Furthermore, great flow dynamic is preferred in a channel if intimate mixing is desired between two streams [9]. Several patterns of channel were investigated formerly to address the significant of mixing such as serpentine shaped channel [10], linked twist map barriers [11], floor-grooved channel [12] and rhombic micromixer [13]. In this project, the simulation is done through configuring the wires assembly in parallel arrangement inside the channel that will induce dynamic mixing via chaotic advection to increase the efficiency of ammonia production.…”