An easily fabricated three-dimensional threaded lemniscate-shaped micromixer for a wide range of flow rates

Abstract

Mixing fluid samples or reactants is a paramount function in the fields of micro total analysis system (lTAS) and microchemical processing. However, rapid and efficient fluid mixing is difficult to achieve inside microchannels because of the difficulty of diffusive mass transfer in the laminar regime of the typical microfluidic flows. It has been well recorded that the mixing efficiency can be boosted by migrating from two-dimensional (2D) to three-dimensional (3D) geometries. Although several 3D chaotic mixers have been designed, most of them offer a high mixing efficiency only in a very limited range of Reynolds numbers (Re). In this work, we developed a 3D fine-threaded lemniscate-shaped micromixer whose maximum numerical and empirical efficiency is around 97% and 93%, respectively, and maintains its high performance (i.e., >90%) over a wide range of 1 < Re < 1000 which meets the requirements of both the lTAS and microchemical process applications. The 3D micromixer was designed based on two distinct mixing strategies, namely, the inducing of chaotic advection by the presence of Dean flow and diffusive mixing through thread-like grooves around the curved body of the mixers. First, a set of numerical simulations was performed to study the physics of the flow and to determine the essential geometrical parameters of the mixers. Second, a simple and cost-effective method was exploited to fabricate the convoluted structure of the micromixers through the removal of a 3D-printed wax structure from a block of cured polydimethylsiloxane. Finally, the fabricated mixers with different threads were tested using a fluorescent microscope demonstrating a good agreement with the results of the numerical simulation. We envisage that the strategy used in this work would expand the scope of the micromixer technology by broadening the range of efficient working flow rate and providing an easy way to the fabrication of 3D convoluted microstructures. Published by AIP Publishing.

A Review on Micromixers

“…The simulation and experimental results showed that the micromixer had a high mixing efficiency of 99% for a wide range of low Re (0.003–30). In addition, Rafeie et al [ 148 ] presented an effective micromixer (mixing efficiency > 90%) which incorporates the 3D spiral and fine-threaded microchannels for a wider range of Re (1–1000) ( Figure 20 c).…”

“… Schematic of the 3D spiral based micromixer ( a ) with two spiral microchannels and an erect channel; ( b ) with double helical channels in opposite directions; and ( c ) with 3D spiral and fine-threaded microchannel. Reproduced with permission from [ 112 , 113 , 148 ]. …”

Method for determining mixing index in microfluidics by RGB color model

“…In other words, HSI ,mix is frame‐dependent. To accommodate frame‐varying mean intensity into the calculation of mixing index, the following equation has been proposed: where HSI ,avg is the average value of the entire pixels contained in a single image frame.…”

“…In other words, I HSI, mix is frame-dependent. To accommodate frame-varying mean intensity into the calculation of mixing index, the following equation has been proposed 6,19,[25][26][27][28] :…”

Biotechnology for Formation of Aromatic Properties of National- Foodstuffs on the Basis of Meat Raw Material under Influence of Bacterial Crops and Chromato-Mass-Spectrometric Analysis of the Flavoring Components

“…Recently, studies of spatial formation of materials on the principle of 3D printing have been developed [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. For computer manufacturing in the space of different objects, information on the component composition of the material is needed.…”