Numerical Evaluation of Liquid Mixing in a Serpentine Square Convergent-divergent Passive Micromixer

2020 ◽  
Vol 15 (2) ◽  
Author(s):  
Shasidhar Rampalli ◽  
T. Manoj Dundi ◽  
S. Chandrasekhar ◽  
V. R. K. Raju ◽  
V. P. Chandramohan
Keyword(s):  
Three Dimensional ◽  
Mixing Efficiency ◽  
Square Wave ◽  
Mixing Performance ◽  
Total Analysis System ◽  
Pure Diffusion ◽  
Passive Mixers ◽  
Passive Micromixer ◽  
Total Analysis ◽  
Analysis System

AbstractMicromixers are crucial components to carry out chemical, biomedical and bio-chemical analyses on µTAS (micro total analysis system) or Lab-on-chips. Simple planar type passive mixers are always most desirable over three dimensional or complex geometries of passive mixers or active mixers as they are less expensive, easy to fabricate, and easy to integrate into complex miniaturized systems. However, at very low Reynolds numbers (0 to 100), due to the inherent laminar nature of the microfluidic flows, mixing remains challenging in passive mixers. Previous studies reported that serpentine square-wave micromixer is one of the simple and effective passive device for micromixing. In the present study, to further enhance the mixing efficiency of the device, horizontal straight portions of serpentine square wave mixer are replaced with convergent-divergent passages and the mixing performance of both mixers are evaluated in the Re range of 0 to 100. It is observed in the low Re (0 to 10), mixing in the square wave mixer with convergent-divergent portions (SQW-CD mixer) is governed completely by pure diffusion as in the case of square wave mixer with straight horizontal portions (SQW mixer). However, at high Re (Re > 10), the presence of convergent-divergent portions in the SQW-CD mixer considerably intensify the stretching and folding of samples in the mixing channel. Additionally, the extra recess available at the bends of SQW-CD mixer creates recirculation zones in the mixer. Therefore, a significant improvement in the mixing performance is achieved at high Re (Re > 10) for SQW-CD mixer as compared to conventional SQW mixer. This would allow shorter mixing lengths for SQW-CD mixer as compared to Sq wave mixer. However, with increase in Re, the rise in pressure drop is considerably high for SQW-CD mixer as compared to SQW mixer.

Numerical simulation of three-dimensional passive micromixer based on the principle of Koch fractal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Siyue Xiong ◽  
Xueye Chen
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Cross Section ◽  
Three Dimensional ◽  
Mixing Efficiency ◽  
Mixing Performance ◽  
Chaotic Convection ◽  
Passive Micromixer ◽  
Koch Fractal ◽  
Koch Fractal Principle

Abstract In this paper, We arrange the obstacles based on the Koch fractal principle (OKF) in the micromixer. By changing the fluid flow and folding the fluid, a better mixing performance is achieved. We improve the mixing efficiency by placing OKF and changing the position of OKF, then we studied the influence of the number of OKF and the height of the micromixer on the mixing performance. The results show that when eight OKF are staggered in the microchannel and the height is 0.2 mm, the mixing efficiency of the OKF micromixer can reach 97.1%. Finally, we compared the velocity cross section and velocity streamline of the fluid, and analyzed the influence of OKF on the concentration trend. Through analysis, it is concluded that OKF can generate chaotic convection in the fluid, and enhance the mixing of fluids by generating vortices and folding the fluid. It can effectively improve the mixing efficiency of the micromixer.

scholarly journals A 3D Printed Jet Mixer for Centrifugal Microfluidic Platforms

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 695 ◽  
Author(s):  
Yunxia Wang ◽  
Yong Zhang ◽  
Zheng Qiao ◽  
Wanjun Wang
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Mixing Efficiency ◽  
Medical Applications ◽  
Microfluidic Platforms ◽  
Mixing Performance ◽  
Wide Range ◽  
3D Printed ◽  
Miscible Liquids ◽  
Biological And Medical Applications

Homogeneous mixing of microscopic volume fluids at low Reynolds number is of great significance for a wide range of chemical, biological, and medical applications. An efficient jet mixer with arrays of micronozzles was designed and fabricated using additive manufacturing (three-dimensional (3D) printing) technology for applications in centrifugal microfluidic platforms. The contact surface of miscible liquids was enhanced significantly by impinging plumes from two opposite arrays of micronozzles to improve mixing performance. The mixing efficiency was evaluated and compared with the commonly used Y-shaped micromixer. Effective mixing in the jet mixer was achieved within a very short timescale (3s). This 3D printed jet mixer has great potential to be implemented in applications by being incorporated into multifarious 3D printing devices in microfluidic platforms.

Detection of Directivity of Fluorescence From a Mixed Specimen Which Consists of Micro Particles Attached Different Fluorescent Substances Using a Light Waveguide Incorporated Optical TAS

2018 ◽  
Author(s):  
Toshifumi Ohkubo ◽  
Nobuyuki Terada ◽  
Yoshikazu Yoshida
Keyword(s):  
Microfluidic Channel ◽  
Laser Source ◽  
Microfluidic Channels ◽  
Fluorescent Substance ◽  
Total Analysis System ◽  
Micro Particles ◽  
Total Analysis ◽  
Light Waveguide ◽  
Analysis System ◽  
Near Future

A resin-based optical total analysis system (O-TAS) which consists both of microfluidic channels and light waveguides [1] is thought to be one of the most promising components in developing a “ubiquitous human healthcare system” in the near future. Along with this technology trend, we have already developed a transparent epoxy-resin-based optical TAS chip which has a specially prepared light waveguide structure of radially arranged configuration at an intersection portion with a microfluidic channel, in order to detect directivity of fluorescence from fluorescent substance attached micro particles [2],[3]. Schematic diagram of the optical TAS is shown in Figure 1. In the latest research, utilizing an AC modulated laser source and time-series averaging function on detected signal waveforms, we could have successfully obtained directivities of fluorescence from 5-μm-diameter particles with higher signal to noise (S/N) ratio [3].

Micro Particle Imaging Velocimetry Measurements in High Aspect Ratio Passive Microfluidic Components

2005 ◽  
Author(s):  
Paul Chiarot ◽  
Pierre Sullivan ◽  
Ridha Ben Mrad
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Particle Imaging Velocimetry ◽  
Passive Component ◽  
Total Analysis System ◽  
Micro Piv ◽  
Micro Total Analysis Systems ◽  
Total Analysis ◽  
Analysis System ◽  
Particle Imaging

In this work, micro particle imaging velocimetry (micro-PIV) was performed on the fundamental components of a micro total analysis system. Specifically, high aspect ratio passive valves and mixers were designed, fabricated, and characterized. The components were built using Micralyne Protolyne technology on a glass substrate and operated at reasonably achievable pressures. The flows through the components were analyzed both qualitatively and quantitatively with the goal of developing a more complete understanding of internal device performance. Using the results of the micro-PIV developed velocity fields it was found that the high aspect ratio passive valves are able to perform at reasonably achievable pressures. However, it was determined that the high aspect ratio passive mixers offer limited performance enhancements because of the low Reynolds number flows. The results of this work contribute to the understanding of passive component operation and address some of the challenges associated with developing completely integrated micro total analysis systems that use passive devices.

scholarly journals Miniaturization of fluorescence sensing in optofluidic devices

2020 ◽  
Vol 24 (9) ◽  
Author(s):  
Daniel Măriuţa ◽  
Stéphane Colin ◽  
Christine Barrot-Lattes ◽  
Stéphane Le Calvé ◽  
Jan G. Korvink ◽  
...  
Keyword(s):  
Lab On A Chip ◽  
Time Data ◽  
Fluorescence Sensing ◽  
Successful Development ◽  
Total Analysis System ◽  
Total Analysis ◽  
Integration Strategies ◽  
Analysis System ◽  
On Chip ◽  
Industrial Sensing

Abstract Successful development of a micro-total-analysis system (µTAS, lab-on-a-chip) is strictly related to the degree of miniaturization, integration, autonomy, sensitivity, selectivity, and repeatability of its detector. Fluorescence sensing is an optical detection method used for a large variety of biological and chemical assays, and its full integration within lab-on-a-chip devices remains a challenge. Important achievements were reported during the last few years, including improvements of previously reported methodologies, as well as new integration strategies. However, a universal paradigm remains elusive. This review considers achievements in the field of fluorescence sensing miniaturization, starting from off-chip approaches, representing miniaturized versions of their lab counter-parts, continuing gradually with strategies that aim to fully integrate fluorescence detection on-chip, and reporting the results around integration strategies based on optical-fiber-based designs, optical layer integrated designs, CMOS-based fluorescence sensing, and organic electronics. Further successful development in this field would enable the implementation of sensing networks in specific environments that, when coupled to Internet-of-Things (IoT) and artificial intelligence (AI), could provide real-time data collection and, therefore, revolutionize fields like health, environmental, and industrial sensing.

Water glass bonding for micro-total analysis system

2002 ◽  
Vol 81 (2-3) ◽  
pp. 187-195 ◽  
Author(s):  
Takeshi Ito ◽  
Kazuharu Sobue ◽  
Seishiro Ohya
Keyword(s):  
Water Glass ◽  
Micro Total Analysis System ◽  
Total Analysis System ◽  
Total Analysis ◽  
Analysis System

A SU-8 microfluidic total analysis system integrating silicon photodiodes and buried waveguides

2005 ◽  
Author(s):  
P. de la Fuente ◽  
J.A. Etxeberria ◽  
J. Berganzo ◽  
M.T. Arroyo ◽  
E. Castano ◽  
...  
Keyword(s):  
Total Analysis System ◽  
Total Analysis ◽  
Analysis System

Analysis of a Novel Y-Y Micromixer for Mixing at a Wide Range of Reynolds Numbers

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Vladimir Viktorov ◽  
Carmen Visconte ◽  
Md Readul Mahmud
Keyword(s):  
Three Dimensional ◽  
Interfacial Area ◽  
Reynolds Numbers ◽  
Mixing Efficiency ◽  
Change Of Direction ◽  
Analysis Technique ◽  
Wide Range ◽  
Passive Micromixer ◽  
In Series ◽  
Flow Through

A novel passive micromixer, denoted as the Y-Y mixer, based on split-and-recombine (SAR) principle is proposed and studied both experimentally and numerically over Reynolds numbers ranging from 1 to 100. Two species are supplied to a prototype via a Y inlet, and flow through four identical elements repeated in series; the width of the mixing channel varies from 0.4 to 0.6 mm, while depth is 0.4 mm. An image analysis technique was used to evaluate mixture homogeneity at four target areas along the mixer. Numerical simulations were found to be a useful support for observing the complex three-dimensional flow inside the channels. Comparison with a known mixer, the tear-drop one, based on the same SAR principle, was also performed, to have a point of reference for evaluating performances. A good agreement was found between numerical and experimental results. Over the examined range of Reynolds numbers Re, the Y-Y micromixer showed at its exit an almost flat mixing characteristic, with a mixing efficiency higher than 0.9; conversely, the tear-drop mixer showed a relevant decrease of efficiency at the midrange. The good performance of the Y-Y micromixer is due to the three-dimensional 90 deg change of direction that occurs in its channel geometry, which causes a fluid swirling already at the midrange of Reynolds numbers. Consequently, the fluid path is lengthened and the interfacial area of species is increased, compensating for the residence time reduction.

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