scholarly journals Numerical Investigation of Mixing by Induced Electrokinetic Flow in T-Micromixer with Conductive Curved Arc Plate

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 915
Author(s):  
Vahabodin Goodarzi ◽  
Saeed Hayati Jafarbeygi ◽  
Ramezan Ali Taheri ◽  
Mikhail Sheremet ◽  
Mohammad Ghalambaz
Keyword(s):  
Flat Plate ◽  
Numerical Study ◽  
Orientation Angle ◽  
Mixing Efficiency ◽  
Span Length ◽  
Symmetric Flow ◽  
Electrokinetic Flow ◽  
Conductive Plate ◽  
Arc Shape

Mixing is essential in microdevices. Therefore, increasing the mixing efficiency has a significant influence on these devices. Using conductive obstacles with special geometry can improve the mixing quality of the micromixers. In this paper, a numerical study on the mixing caused by an induced-charge electrokinetic micromixer was carried out using a conductive plate with a curved arc shape instead of a conductive flat plate or other non-conductive obstacles for Newtonian fluids. This study also explored the effect of the different radius curves, span length, the number of curved arc plates in the channel, the pattern of arrangement, concavity direction, and the orientation angle against the flow on the mixing. Furthermore, the efficiency of the T-micromixer against a flow with a low diffusion coefficient was investigated. It should be noted that the considered channel is symmetric regarding to the middle horizontal plane and an addition of flat plate reflects a formation of symmetric flow structures that do not allow to improve the mixture process. While an addition of non-symmetric curved arc plates al-lows to increase the mixing by creating vortices. These vortices were created owing to the non-uniform distribution of induced zeta potential on the curved arc plate. A rise in the span length of the curved arc plate when the radius was constant improved the mixing. When three arc plates in one concavity direction were used, the mixing efficiency was 91.86%, and with a change in the concavity direction, the mixing efficiency increased to 95.44%. With a change in the orientation angle from 0 to 25, the mixing efficiency increased by 19.2%.

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.

A Non-Cooperative Game Analysis of Competition between Content Providers in the Internet Market

2019 ◽  
Vol 15 (1) ◽  
pp. 88-104 ◽  
Author(s):  
M'hamed Outanoute ◽  
Hamid Garmani ◽  
Mohamed Baslam ◽  
Rachid El Ayachi ◽  
Belaid Bouikhalene
Keyword(s):  
Quality Of Service ◽  
Detailed Analysis ◽  
Cooperative Game ◽  
Price Of Anarchy ◽  
Numerical Study ◽  
Pure Nash Equilibrium ◽  
Game Analysis ◽  
Different Types ◽  
Internet Market

In internet market, content providers (CPs) continue to play a primordial role in the process of accessing different types of data. Competition in this area is fierce; customers are looking for providers that offer them good content (credibility of content and quality of service) with a reasonable price. In this work, the authors analyze this competition between CPs and the economic influence of their strategies on the market. The authors formulate their problem as a non-cooperative game among multiple CPs for the same market. Through a detailed analysis, the researchers prove uniqueness of a pure Nash Equilibrium (NE). Furthermore, a fully distributed algorithm to converge on the NE point is presented. In order to quantify how efficient the NE point is, a detailed analysis of the Price of Anarchy (PoA) is adopted to ensure the performance of the system at equilibrium. Finally, an extensive numerical study is provided to describe the interactions between CPs and to point out the importance of quality of service (QoS) and credibility of content in the market.

Film cooling characteristics on a grooved surface with different injection orientation angles

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Peng Yang ◽  
Guangchao Li ◽  
Jianyong Zhu
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
Orientation Angle ◽  
Hole Injection ◽  
Blowing Ratio ◽  
Reverse Trend ◽  
Grooved Surface ◽  
Shaped Hole

Abstract The film effectiveness was investigated on a grooved surface with the injection orientation angles of 30°, 90°, and 150° at the blowing ratios of 0.5, 0.8, 1.1, and 1.4. The injection orientation angle and the groove on the surface caused the effect of the various and irregular shaped hole injection due to the different orientation injection. The results showed that the new phenomenon of film effectiveness distributions was found on the grooved surface compared with the flat plate case. Film effectiveness distributions for the β = 30° were found to be the discontinuous strips. The surface averaged film effectiveness with the orientation angle of 30° was found to decrease with the increase of the blowing ratio. Additionally, the reverse trend was observed with the orientation angle of 150°. The film effectiveness with the orientation angle of 90° only slightly changed with the increase of the blowing ratio.

Film cooling characteristics on a grooved surface with different injection orientation angles

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Peng Yang ◽  
Guangchao Li ◽  
Jianyong Zhu
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
Orientation Angle ◽  
Hole Injection ◽  
Blowing Ratio ◽  
Reverse Trend ◽  
Grooved Surface ◽  
Shaped Hole

AbstractThe film effectiveness was investigated on a grooved surface with the injection orientation angles of 30°, 90°, and 150° at the blowing ratios of 0.5, 0.8, 1.1, and 1.4. The injection orientation angle and the groove on the surface caused the effect of the various and irregular shaped hole injection due to the different orientation injection. The results showed that the new phenomenon of film effectiveness distributions was found on the grooved surface compared with the flat plate case. Film effectiveness distributions for the β = 30° were found to be the discontinuous strips. The surface averaged film effectiveness with the orientation angle of 30° was found to decrease with the increase of the blowing ratio. Additionally, the reverse trend was observed with the orientation angle of 150°. The film effectiveness with the orientation angle of 90° only slightly changed with the increase of the blowing ratio.

Numerical Study of Boundary Layers With Reverse Wedge Flows Over a Semi-Infinite Flat Plate

2009 ◽  
Vol 77 (2) ◽  
Author(s):  
R. Ahmad ◽  
K. Naeem ◽  
Waqar Ahmed Khan
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Numerical Study ◽  
Boundary Layer Equation ◽  
Wedge Angle ◽  
Adverse Pressure Gradient ◽  
Problem Solution ◽  
Weighted Residual Method ◽  
Boundary Layer Problem ◽  
Layer Problem

This paper presents the classical approximation scheme to investigate the velocity profile associated with the Falkner–Skan boundary-layer problem. Solution of the boundary-layer equation is obtained for a model problem in which the flow field contains a substantial region of strongly reversed flow. The problem investigates the flow of a viscous liquid past a semi-infinite flat plate against an adverse pressure gradient. Optimized results for the dimensionless velocity profiles of reverse wedge flow are presented graphically for different values of wedge angle parameter β taken from 0≤β≤2.5. Weighted residual method (WRM) is used for determining the solution of nonlinear boundary-layer problem. Finally, for β=0 the results of WRM are compared with the results of homotopy perturbation method.

Simulation of Two Designs of Micro-Mixers With Enhanced Advection Mechanisms

2011 ◽  
Author(s):  
S. A. Kazemi ◽  
M. Passandideh-Fard ◽  
J. Esmaeelpanah
Keyword(s):  
Numerical Study ◽  
Control Volume ◽  
Numerical Technique ◽  
Chaotic Advection ◽  
Mixing Efficiency ◽  
Mixing Length ◽  
Surface Development ◽  
Mixer Design ◽  
Gas Liquid Flow ◽  
Micro Mixer

In this paper, a numerical study of two new designs of passive micro-mixers based on chaotic advection is presented. The advection phenomenon in a T-shaped micro-mixer is enhanced using a segmented gas-liquid flow; and a peripheral/axial mixing mechanism. The simulations are performed for two non-reactive miscible gases: oxygen and methanol. The numerical model employed for this study is based on the solution of the physical governing equations namely the continuity, momentum, species transport and an equation to track the free surface development. The equations are discretized using a control volume numerical technique. The distribution of the species concentration within the domain is calculated based on which a mixing intensity factor is introduced. This factor is then used as a criterion for the mixing length. In the first micro-mixer design with a drop injection mechanism for a typical condition, the mixing length is reduced by nearly 15%. Compared to that of a simple T-shaped micro-mixer with the same flow rates, the two gases interface area is increased in axisymmetric micro-mixer leading to an increase of the mixing efficiency and a reduction of the mixing length. Also, the effects of the baffles height and span on the mixing efficiency and length in axisymmetric micro-mixer are studied. Having baffles in the channel can substantially decrease the mixing length.

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