A three-dimensional microfluidic mixer of a homogeneous mixing efficiency fabricated by ultrafast laser internal processing of glass

We demonstrate a microfluidic mixer of high mixing efficiency in fused silica substrate using femtosecond laser-induced wet etching and hydroxide-catalysis bonding method. The micromixer has a three-dimensional geometry, enabling efficient mixing based on Baker’s transformation principle. The cross-sectional area of the fabricated micromixer was 0.5 × 0.5 mm2, enabling significantly promotion of the throughput of the micromixer. The performance of the fabricated micromixers was evaluated by mixing up blue and yellow ink solutions with a flow rate as high as 6 mL/min.

Download Full-text

A Numerical Study of Sub-Millisecond Integrated Mix-and-Inject Microfluidic Devices for Sample Delivery at Synchrotron and XFELs

Applied Sciences ◽

10.3390/app11083404 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3404

Author(s):

Majid Hejazian ◽

Eugeniu Balaur ◽

Brian Abbey

Keyword(s):

Molecular Dynamics ◽

Flow Rate ◽

Numerical Study ◽

Three Dimensional ◽

Microfluidic Devices ◽

Liquid Jets ◽

Mixing Efficiency ◽

X Ray Diffraction ◽

Cross Sectional ◽

Time Required

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution for studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency and time-resolution achievable using microfluidic mixers within the parameter range required for producing stable liquid jets. Three-dimensional simulations, validated by experimental data, are used to determine the velocity and concentration distribution within these devices. The results show that by adopting a serpentine geometry, it is possible to induce chaotic mixing, which effectively reduces the time required to achieve a homogeneous mixture for sample delivery. Further, we investigate the effect of flow rate and the mixer microchannel size on the mixing efficiency and minimum time required for complete mixing of the two solutions whilst maintaining a stable jet. In general, we find that the smaller the cross-sectional area of the mixer microchannel, the shorter the time needed to achieve homogeneous mixing for a given flow rate. The results of these simulations will form the basis for optimised designs enabling the study of molecular dynamics occurring on millisecond timescales using integrated mix-and-inject microfluidic devices.

Download Full-text

An Enhanced One-Layer Passive Microfluidic Mixer With an Optimized Lateral Structure With the Dean Effect

Journal of Fluids Engineering ◽

10.1115/1.4030288 ◽

2015 ◽

Vol 137 (9) ◽

Cited By ~ 28

Author(s):

Teng Zhou ◽

Yifan Xu ◽

Zhenyu Liu ◽

Sang Woo Joo

Keyword(s):

Reynolds Number ◽

Topology Optimization ◽

Optimization Method ◽

Mixing Efficiency ◽

Boolean Operation ◽

Microfluidic Mixer ◽

Wide Range ◽

The One ◽

Lateral Structure ◽

Topology Optimization Method

Topology optimization method is applied to a contraction–expansion structure, based on which a simplified lateral flow structure is generated using the Boolean operation. A new one-layer mixer is then designed by sequentially connecting this lateral structure and bent channels. The mixing efficiency is further optimized via iterations on key geometric parameters associated with the one-layer mixer designed. Numerical results indicate that the optimized mixer has better mixing efficiency than the conventional contraction–expansion mixer for a wide range of the Reynolds number.

Download Full-text

Computer modelling and simulation of a novel printing head for complex tissue engineering constructs

MATEC Web of Conferences ◽

10.1051/matecconf/202031801045 ◽

2020 ◽

Vol 318 ◽

pp. 01045

Author(s):

Gokhan Ates

Keyword(s):

Tissue Engineering ◽

Computer Modelling ◽

Three Dimensional ◽

Biological Tissues ◽

Biological Properties ◽

Functionally Graded ◽

Mixing Efficiency ◽

Tissue Constructs ◽

Multiple Materials ◽

Graded Structures

In tissue engineering, three-dimensional functional scaffolds with tailored biological properties are needed to be able to mimic the hierarchical structure of biological tissues. Recent developments in additive biomanufacturing allow to extrude multiple materials enabling the fabrication of more sophisticated tissue constructs. These multi-material biomanufacturing systems comprise multiple printing heads through which individual materials are sequentially printed. Nevertheless, as more printing heads are added the fabrication process significantly decreases, since it requires mechanical switching among the physically separated printheads to enable printing multiple materials. In addition, this approach is not able to create biomimetic tissue constructs with property gradients. To address these limitations, this paper presents a novel static mixing extrusion printing head to enable the fabrication of multi-material, functionally graded structures using a single nozzle. Computational fluid dynamics (CFD) was used to numerically analyze the influence of Reynolds number on the flow pattern of biomaterials and mixing efficiency considering different miscible materials.

Download Full-text

Analysis of Mixing Efficiency in a Multi-Cut Transfermix

Rubber Chemistry and Technology ◽

10.5254/1.3538773 ◽

1995 ◽

Vol 68 (5) ◽

pp. 773-782 ◽

Cited By ~ 3

Author(s):

Tao Li ◽

Hongfei Cheng ◽

Ica Manas-Zloczower

Keyword(s):

Three Dimensional ◽

Mixing Efficiency ◽

Power Law Model ◽

Screw Extruder ◽

Axial Pressure ◽

Three Dimensional Flow ◽

Single Screw ◽

Single Screw Extruder ◽

Model Fluid ◽

Constant Output

Abstract Three-dimensional flow patterns of a power-law model fluid in a Multi-Cut Transfermix were calculated. A particle tracking algorithm was used to study the dynamics of mixing. Distributive mixing efficiency was quantified in terms of length stretch distributions and average values. The influence of rotational speed and axial pressure difference on mixing efficiency, under constant output was analyzed. The mixing performances in the MCT was also compared with that in a single screw extruder with the same dimensions as the entrance region of MCT and operating at the same flow rate.

Download Full-text

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

Journal of Mechanics ◽

10.1017/s1727719100000988 ◽

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.

Download Full-text

A 3D Printed Jet Mixer for Centrifugal Microfluidic Platforms

Micromachines ◽

10.3390/mi11070695 ◽

2020 ◽

Vol 11 (7) ◽

pp. 695 ◽

Cited By ~ 1

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.

Download Full-text

Flow Measurements in a Model Burner—Part 2

Journal of Fluids Engineering ◽

10.1115/1.2910140 ◽

1993 ◽

Vol 115 (2) ◽

pp. 309-316

Author(s):

D. F. G. Dura˜o ◽

M. V. Heitor ◽

A. L. N. Moreira

Keyword(s):

Laser Doppler Velocimetry ◽

Swirling Flow ◽

Laser Sheet ◽

Three Dimensional ◽

Swirling Flows ◽

Dimensional Structure ◽

Mixing Efficiency ◽

Flow Measurements ◽

Circular Jets ◽

Turbulence Production

The isothermal swirling flow in the vicinity of a model oxy-fuel industrial burner is analyzed with laser-Doppler velocimetry together with laser-sheet visualization. The burner consists of a central axisymmetric swirling jet surrounded by sixteen circular jets, simulating the injection of oxygen in practical burners. The results extend those obtained for non-swirling flows, and presented in Part 1 of this paper, to the analysis of the dependence of the mixing efficiency of the burner assembly upon the swirl motion of the central jet and have the necessary detail to allow to assess the accuracy of calculation procedures of the flow in industrial burners. It is shown that swirl attenuates the three-dimensional structure typical of multijet flows in such a way that turbulence production and transport in the near burner zone are dominated by swirl-induced processes.

Download Full-text

Dielectrophoretic Mixing With Novel Electrode Geometry

Volume 2: Fora ◽

10.1115/fedsm2009-78260 ◽

2009 ◽

Author(s):

G. Naga Siva Kumar ◽

Sushanta K. Mitra ◽

Subir Bhattacharjee

Keyword(s):

Electric Field ◽

Cell Activation ◽

Colloidal Particles ◽

Colloidal Suspension ◽

Three Dimensional ◽

Colloidal Suspensions ◽

Navier Stokes ◽

Mixing Efficiency ◽

Computational Domain ◽

Element Analysis

Electrokinetic mixing of analytes at micro-scale is important in several biochemical applications like cell activation, DNA hybridization, protein folding, immunoassays and enzyme reactions. This paper deals with the modeling and numerical simulation of micromixing of two different types of colloidal suspensions based on principle of dielectrophoresis (DEP). A mathematical model is developed based on Laplace, Navier-Stokes, and convection-diffusion-migration equations to calculate electric field, velocity, and concentration distributions, respectively. Mixing of two colloidal suspensions is simulated in a three-dimensional computational domain using finite element analysis considering dielectrophoretic, gravitational and convective (advective)–diffusive forces. Phase shifted AC signal is applied to the alternating electrodes for achieving the mixing of two different colloidal suspensions. The results indicate that the electric field and DEP forces are maximum at the edges of the electrodes and become minimum elsewhere. As compared to curved edges, straight edges of electrodes have lower electric field and DEP forces. The results also indicate that DEP force decays exponentially along the height of the channel. The effect of DEP forces on the concentration profile is studied. It is observed that, the concentration of colloidal particles at the electrodes edges is very less compared to elsewhere. Mixing of two colloidal suspensions due to diffusion is observed at the interface of the two suspensions. The improvement in mixing after applying the repulsive DEP forces on the colloidal suspension is observed. Most of the mixing takes place across the slant edges of the triangular electrodes. The effect of electrode pairs and the mixing length on degree of mixing efficiency are also observed.

Download Full-text

Mixing and Combustion Improvement Using Jet Injection Into Swirling Flowfields

Energy Conversion ◽

10.1115/imece2002-39600 ◽

2002 ◽

Author(s):

David G. Lilley

Keyword(s):

Research Program ◽

Swirling Flow ◽

Three Dimensional ◽

Computer Code ◽

Theoretical Research ◽

Mixing Efficiency ◽

Jet Injection ◽

Mean Velocity ◽

Turbulence Data ◽

Secondary Injection

The aerodynamics benefits of lateral jet injection into swirling crossflow have long been recognized and used by combustion engineers. Studies are reported here on experimental and theoretical research on lateral jet injection into typical combustor flowfields for low-speed turbulent swirling flow conditions in the absence of combustion. The main flow is air in a round cross-sectioned plexiglass tube. The degree of swirl can be varied by varying the angles of the blades of an annular swirler, located upstream of the test section. Lateral jet injection is normal to the main airflow, from round-sectioned nozzles. Either a single lateral jet or two diametrically opposed jets are used for this secondary injection of air into the main airflow. The principal aim is to investigate the trajectory, penetration and mixing efficiency of the lateral injection. Flow visualization with helium-filled soap bubbles and multi-spark ionized path techniques, five-hole pitot probe time-mean velocity measurements, and single-wire time-mean velocity and turbulence data (normal and shear stress) have been obtained in the experimental research program. A fully three-dimensional computer code with two-equation turbulence model has been developed and used in the theoretical research program.

Download Full-text