Abstract
A fast mixing is critical for subsequent practical development of microfluidic devices, which are often used for assays in the detection of reagents and samples. The present work sets up computational fluid dynamics simulations to explore the flow characteristic and mixing mechanism of fluids in cross-shaped mixers within the laminar regime. First, the effects of increasing an operating parameter on local mixing quality along the microchannels are investigated. It is found that sufficient diffusion cannot occur even though the concentration gradient is large at a high Reynolds number. Meanwhile, a method for calculating local mixing efficiency is also characterized. The mixing efficiency varies exponentially with the flow distance. Second, in order to optimize the cross-shaped mixer, the effects of design parameters, namely aspect ratio, mixing angle and blockage, on mixing quality are captured and the visualization of velocity and concentration distribution are demonstrated. The results show that the aspect ratio and the blockage play an important role in accelerating the mixing process. They can improve the mixing efficiency by increasing the mass transfer area and enhancing the chaotic advection, respectively. In contrast, the inflow angle that affects dispersion length is not an effective parameter. Besides, the surface roughness, which makes the disturbance of fluid flow by roughness more obvious, is considered. Three types of rough elements bring benefits for enhancing mixing quality due to the convection induced by the lateral velocity.
Highlights
In recent years, the lab on a chip (LOC) and micro total analysis systemtechnologies have drawn considerable attention in the detection fields of biology [1], chemistry [2] and medicine [3] due to their unique advantages such as fast analysis speed, less sample consumption, safe operating environment and high throughput [4,5,6]
Compared with conventional macro-scale reactors, the performances of these micro-scale devices are severely restricted by the chemical reaction efficiency, which reduces the assay accuracy
It is known that the mixing of reagents should be done quickly before obvious chemical reaction progress occurs
Summary
The lab on a chip (LOC) and micro total analysis system (μTAS). Technologies have drawn considerable attention in the detection fields of biology [1], chemistry [2] and medicine [3] due to their unique advantages such as fast analysis speed, less sample consumption, safe operating environment and high throughput [4,5,6]. Compared with conventional macro-scale reactors, the performances of these micro-scale devices are severely restricted by the chemical reaction efficiency, which reduces the assay accuracy. It is known that the mixing of reagents should be done quickly before obvious chemical reaction progress occurs. The flow in the microchannel remains laminar and the mass transport process depends mainly on molecular diffusion [7]. The mixing quality can be improved by increasing the interfacial area for mass transport and by minimizing the diffusion distance [9]
Sign-in/Register to view highlights & summary 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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
