A Novel Three-Dimensional Passive Micromixer with Replaceable Mixing Chamber

2014 ◽  
Vol 513-517 ◽  
pp. 3090-3093
Author(s):  
He Zhang ◽  
Li Tian ◽  
Xiao Wei Han ◽  
Xiao Wei Liu
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Mixing Efficiency ◽  
Mixing Chamber ◽  
Result Show ◽  
Passive Micromixer ◽  
Left And Right

In this paper, we design and fabricate a three-dimensional passive-micromixer with a replaceable mixing chamber. The rectangular mixing chamber has a dimension of 20 mm × 3 mm in length and width and 2 mm in height, the chamber can be fitted with different microstructures to accelerate mixing. Then, we compare the no structure chamber to left and right interdigitated chamber by using numerical simulation, the result show that the mixing efficiency has been significantly improved. The photomicrographs proved the effectiveness of the design finally.

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.

A Study on Mixing Efficiency in a Two-Channel Circular Micromixer

2006 ◽  
Vol 22 (4) ◽  
pp. 331-338
Author(s):  
M. Chang ◽  
Y.-H. Hu ◽  
S.-W. Chau ◽  
K.-H. Lin
Keyword(s):  
Three Dimensional ◽  
Numerical Prediction ◽  
Mixing Efficiency ◽  
Experimental Measurements ◽  
Inspection Method ◽  
Flow Rates ◽  
Two Fluids ◽  
Finite Volume Discretization ◽  
Mixing Chamber ◽  
Image Inspection

AbstractThe mixing behavior of a two-channel micromixer with a circular mixing chamber at four different chamber depths and six different flow rates had been investigated. Experiments were implemented with the mixings of two fluids. An image inspection method using the variance of the image gray level contrast as the measurement parameter to determine the mixing efficiency distribution in these mixers. The steady, three-dimensional and laminar flow fields inside the micromixers were also simulated numerically with a finite volume discretization. Through the numerical integration over the chamber depth, the three-dimensional numerical prediction could be compressed into a two-dimensional result, which could be directly used to compare with the experimental measurements. Experimental results show that the measured mixing efficiency is raised with the increase of chamber depth. The numerical prediction of mixing efficiency agreed qualitatively with those obtained from the experimental measurements, while the ratio of the depth to diameter of the mixing chamber is big enough to eliminate the viscosity effect.

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.

Numerical Simulation of a Novel Passive Micromixer With Curved Channel and Slanted Grooves

2010 ◽  
Author(s):  
Yanfeng Fan ◽  
Ibrahim Hassan
Keyword(s):  
Numerical Simulation ◽  
Rotation Angle ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Mixing Efficiency ◽  
Curved Channel ◽  
Passive Micromixer ◽  
Present Design ◽  
High Reynolds ◽  
Rotation Strength

A novel passive micromixer with slanted grooves on the top and bottom of curved microchannel, denoted as CMG, is investigated numerically. The total mixing length is fixed at approximate 5.17 mm. The curved channel is applied to generate Dean vortices in the microchannel at high Reynolds numbers. The slanted grooves are used to assist to create the rotation of flow at low Reynolds numbers. The validation of present numerical simulation is done through the comparison with literatures. Three parameters, the slanted angle (θ), the grooves width angle (ω), and the height ratio of grooves (Hg/H), are selected to achieve the optimization. The tested Reynolds numbers range from 1 to 50. Compared with slanted grooved micromixer (SGM) and the curved microchannel (CM), the present micromixer has better mixing efficiency. In order to investigate the flow characteristics, a particle located at one inlet is selected and the trajectory is performed to observe the flow rotation. The rotation angle is defined to estimate the rotation strength. The results show that CMG has largest rotation angle than CM and SGM, which indicates a stronger rotation/helical motion generated in the curved channel. The mixing efficiency of present design has 60% at Re = 50 with a pressure drop of 1.8 kPa.

Mixing Enhancement of a Passive Micromixer by Applying Boundary Protrusion Structures

2009 ◽  
Vol 74 ◽  
pp. 77-80 ◽  
Author(s):  
Chang Yu Hsieh ◽  
An Shik Yang
Keyword(s):  
Three Dimensional ◽  
Mixing Efficiency ◽  
Mixing Enhancement ◽  
Shape Effect ◽  
Governing Equations ◽  
Species Concentration ◽  
Flow Transport ◽  
Mixing Behavior ◽  
Passive Micromixer ◽  
Simplec Algorithm

The purpose of this study is to examine the mixing behavior of two test fluids flowing via a passive micromixer with protruded structures arranged at the boundary of the mixer. In the analysis, the theoretical model was based on the three-dimensional conservation equations of mass, momentum and species concentration; whereas, the governing equations were numerically solved by using an iterative SIMPLEC algorithm to resolve flow/transport properties. The predicted mixing efficiency at different axial locations was compared with available measured results in the literature for code validation. Numerical experiments were extended to study the shape effect of boundary protrusion structures on mixing enhancement of a passive micromixer with diamond-shaped obstructions.

scholarly journals Chaotic Micromixer Based on 3D Horseshoe Transformation

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 398 ◽  
Author(s):  
He Zhang ◽  
Xin Li ◽  
Rongyan Chuai ◽  
Yingjie Zhang
Keyword(s):  
Convective Diffusion ◽  
Three Dimensional ◽  
Mixing Efficiency ◽  
Inverse Transformation ◽  
Mixing Index ◽  
Chaotic Flow ◽  
Buffer Solutions ◽  
Mixing Chamber ◽  
Microscope Images ◽  
Ph Buffer

To improve the efficiency of mixing under laminar flow with a low Reynolds number (Re), a novel three-dimensional Horseshoe Transformation (3D HT) was proposed as the basis for the design of a micromixer. Compared with the classical HT, the Lyapunov exponent of the 3D HT, which was calculated based on a symbolic dynamic system, proved the chaotic enhancement. Based on the 3D HT, a micromixer with a mixing length of 12 mm containing six mixing units was obtained by sequentially applying “squeeze”, “stretch”, “twice fold”, “inverse transformation”, and “intersection” operations. Numerical simulation and Peclet Number (Pe) calculations indicated that when the squeeze amplitude 0 < α < 1/2, 0 < β < 1/2, the stretch amplitude γ > 4, and Re ≥ 1, the mass transfer in the mixer was dominated by convective diffusion induced by chaotic flow. When Re = 10, at the outlet of the mixing chamber, the simulated mixing index was 96.4%, which was far less than the value at Re = 0.1 (σ = 0.041). Microscope images of the mixing chamber and the curve trend of pH buffer solutions obtained from a mixing experiment were both consistent with the results of the simulation. When Re = 10, the average mixing index of the pH buffer solutions was 91.75%, which proved the excellent mixing efficiency of the mixer based on the 3D HT.

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 WITH VARIABLE-ANGLE GROOVES AND BAFFLES

2021 ◽  
pp. 2150037
Author(s):  
SIYUE XIONG ◽  
XUEYE CHEN
Keyword(s):  
Fluid Flow ◽  
Three Dimensional ◽  
Geometric Parameters ◽  
Mixing Efficiency ◽  
Flow State ◽  
Number Range ◽  
Variable Angle ◽  
Structure Changes ◽  
Chaotic Convection ◽  
Passive Micromixer

In this paper, we have studied the effect of variable-angle grooves and baffles on the mixing efficiency of the micromixer. In order to explore the influence on the micromixer with different types of grooves and baffles, we designed grooves and baffles with different geometric parameters and placed them in T-channels to interfere with fluid flow. We studied VAM30∘ (variable-angle grooves and baffles micromixer with an angle of 30∘) directions and distributions as well as their different groove depths and baffle heights affect the mixing performance. We tried to divide the grooves and baffles into five groups, and discussed the effects of staggered depth and height on mixing efficiency. The mixing efficiencies of micromixer in the Re (Reynolds number) range of 0.1–100 were calculated, and the fluid flow in the microchannel was analyzed. The simulation results show that VAM30∘ is more favorable for solution mixing. The mixing efficiency of the micromixer could reach 98.9% with the change of different geometric parameters. This is because when the structure changes, the flow state of the fluid is improved, which is conducive to lengthening the residence time of the fluid in the channel. With the increase of Re, it is also conducive to enhancing the chaotic convection and improving the mixing efficiency.

The three-dimensional structure of frozen-hydrated left- and right-handed forms of bacterial flagellar filaments from an identical serotype

1986 ◽  
Vol 44 ◽  
pp. 298-299
Author(s):  
S. Trachtenberg ◽  
D. J. DeRosier
Keyword(s):  
Ionic Strength ◽  
Basal Body ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Protein Species ◽  
Liquid Environment ◽  
Bacterial Flagellum ◽  
Left And Right ◽  
Rotary Motor ◽  
Helical Parameters

The bacterial cell is propelled through the liquid environment by means of one or more rotating flagella. The bacterial flagellum is composed of a basal body (rotary motor), hook (universal coupler), and filament (propellor). The filament is a rigid helical assembly of only one protein species — flagellin. The filament can adopt different morphologies and change, reversibly, its helical parameters (pitch and hand) as a function of mechanical stress and chemical changes (pH, ionic strength) in the environment.

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