Three Dimensional Triangle Chaotic Micromixer

2014 ◽  
Vol 875-877 ◽  
pp. 1189-1193 ◽  
Author(s):  
Lin Li ◽  
Qing De Chen ◽  
C.T. Tsai
Keyword(s):  
Numerical Investigation ◽  
Three Dimensional ◽  
Microfluidic System ◽  
Chaotic Advection ◽  
Mixing Efficiency ◽  
Mixing Index ◽  
Ansys Fluent ◽  
Essential Component ◽  
Highly Efficient

Micromixer is essential component of microfluidic system which has wide application in the field of chemistry and biochemistry. A highly efficient and easily fabricated three dimensional micromixer based on chaotic advection is proposed and investigated. The depth of 25μm for each layer of micromixer and two kinds of fluids, which have viscosities of 0.00097kgm-1s-1and 0.186kgm-1s-1with Re number from 0.001 to 150, are adopted for numerical investigation of mixing efficiency by using ANSYS-Fluent. High mixing index of more than 90% can be obtained by using less than 300μm of length under Re number of 0.01 for mixing Fluid 1. However, it requires 850μm to achieve mixing index of more than 90% for hard-to-mix Fluid 2.

scholarly journals Numerical Investigation of Liquid–Liquid Mixing in Modified T Mixer with 3D Obstacles

2021 ◽  
pp. 25-32
Author(s):  
Md. Readul Mahmud
Keyword(s):  
Numerical Investigation ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Channel Length ◽  
Navier Stokes ◽  
Mixing Efficiency ◽  
Mixing Performance ◽  
Wide Range

The fluids inside passive micromixers are laminar in nature and mixing depends primarily on diffusion. Hence mixing efficiency is generally low, and requires a long channel length and longtime compare to active mixers. Various designs of complex channel structures with/without obstacles and three-dimensional geometries have been investigated in the past to obtain an efficient mixing in passive mixers. This work presents a design of a modified T mixer. To enhance the mixing performance, circular and hexagonal obstacles are introduced inside the modified T mixer. Numerical investigation on mixing and flow characteristics in microchannels is carried out using the computational fluid dynamics (CFD) software ANSYS 15. Mixing in the channels has been analyzed by using Navier–Stokes equations with water-water for a wide range of the Reynolds numbers from 1 to 500. The results show that the modified T mixer with circular obstacles has far better mixing performance than the modified T mixer without obstacles. The reason is that fluids' path length becomes longer due to the presence of obstacles which gives fluids more time to diffuse. For all cases, the modified T mixer with circular obstacle yields the best mixing efficiency (more than 60%) at all examined Reynolds numbers. It is also clear that efficiency increase with axial length. Efficiency can be simply improved by adding extra mixing units to provide adequate mixing. The value of the pressure drop is the lowest for the modified T mixer because there is no obstacle inside the channel. Modified T mixer and modified T mixer with circular obstacle have the lowest and highest mixing cost, respectively. Therefore, the current design of modified T with circular obstacles can act as an effective and simple passive mixing device for various micromixing applications.

scholarly journals A Novel High-Throughput Chaotic Advection Microreactor for the Preparation of Uniform BaSO4 Nanoparticles

2021 ◽  
Author(s):  
Hua Yang ◽  
Shi-Xiao Wei ◽  
Han Chen ◽  
Lang Chen ◽  
Chak-tong Au ◽  
...  
Keyword(s):  
High Throughput ◽  
Three Dimensional ◽  
Volumetric Flow Rate ◽  
Secondary Flows ◽  
Chaotic Advection ◽  
Narrow Particle Size Distribution ◽  
Chaotic Mixing ◽  
Mixing Efficiency ◽  
Size Uniformity ◽  
Average Size

Owing to high mixing efficiency, microreactors are used to synthesize uniform BaSO4 nanoparticles, but application in industrial scale is limited due to poor throughput. In this work, a high-throughput passive four-stage asymmetric oscillating feedback microreactor using chaotic mixing mechanism was developed to prepare BaSO4 nanoparticles of high size uniformity. Three-dimensional unsteady simulations showed that chaotic mixing could be induced by three unique secondary flows (i.e., vortex, recirculation, and oscillation), and the fluid oscillation mechanism was examined in detail. Simulations and Villermaux-Dushman experiments indicate that almost complete mixing in molecular level could be achieved when total volumetric flow rate Qtotal was larger than 10 mL/min, and the prepared BaSO4 nanoparticles were with narrow particle size distribution (PSD). Through the adjustment of Qtotal and reactant concentrations, it is easy to control the average size. An average size of 26 nm with narrow PSD could be achieved at Qtotal = 160 mL/min.

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.

Experimental and Numerical Analysis of a Motorcycle Air Intake System Aerodynamics and Performance

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
M. A. Abd Halim ◽  
N. A. R. Nik Mohd ◽  
M. N. Mohd Nasir ◽  
M. N. Dahalan
Keyword(s):  
Combustion Process ◽  
Three Dimensional ◽  
Engine Performance ◽  
Internal Flow ◽  
Rapid Expansion ◽  
Navier Stokes ◽  
Turbulent Fluctuation ◽  
Ansys Fluent ◽  
Induction System ◽  
Acceleration And Deceleration

Induction system or also known as the breathing system is a sub-component of the internal combustion system that supplies clean air for the combustion process. A good design of the induction system would be able to supply the air with adequate pressure, temperature and density for the combustion process to optimizing the engine performance. The induction system has an internal flow problem with a geometry that has rapid expansion or diverging and converging sections that may lead to sudden acceleration and deceleration of flow, flow separation and cause excessive turbulent fluctuation in the system. The aerodynamic performance of these induction systems influences the pressure drop effect and thus the engine performance. Therefore, in this work, the aerodynamics of motorcycle induction systems is to be investigated for a range of Cubic Feet per Minute (CFM). A three-dimensional simulation of the flow inside a generic 4-stroke motorcycle airbox were done using Reynolds-Averaged Navier Stokes (RANS) Computational Fluid Dynamics (CFD) solver in ANSYS Fluent version 11. The simulation results are validated by an experimental study performed using a flow bench. The study shows that the difference of the validation is 1.54% in average at the total pressure outlet. A potential improvement to the system have been observed and can be done to suit motorsports applications.

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

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.

scholarly journals Enhanced bacterial disinfection by CuI–BiOI/rGO hydrogel under visible light irradiation

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20446-20456
Author(s):  
Xi Ma ◽  
Ziwei Wang ◽  
Haoguo Yang ◽  
Yiqiu Zhang ◽  
Zizhong Zhang ◽  
...  
Keyword(s):  
Electron Transport ◽  
Visible Light ◽  
Network Structure ◽  
Visible Light Irradiation ◽  
Three Dimensional ◽  
Light Irradiation ◽  
Transport Capacity ◽  
Highly Efficient ◽  
Dimensional Network ◽  
Bacterial Disinfection

Compared with traditional layered graphene, graphene hydrogels have been used to construct highly efficient visible light-excited photocatalysts due to their particular three-dimensional network structure and efficient electron transport capacity.

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