The Simulation and Experimental Analysis of Hydrodynamic Focusing Effect inside a Rectangular Microchannel

2015 ◽  
Vol 645-646 ◽  
pp. 449-454
Author(s):  
Shuai Jie Feng ◽  
Xin Qun Shi ◽  
Jing Zeng ◽  
Yan Peng ◽  
Mei Liu
Keyword(s):  
Aspect Ratio ◽  
Flow Rate ◽  
Cross Sections ◽  
Experimental Analysis ◽  
Rate Ratio ◽  
Flow Rate Ratio ◽  
Hydrodynamic Focusing ◽  
Rectangular Microchannel ◽  
Focusing Effect ◽  
Simulation Results

This paper models the hydrodynamic focusing performance of a micro-fluidic chip with rectangular cross-sections, and the relationships between the aspect ratio, flow rate ratio of sheath flows to the sample flow, and dimensions and position of the focused sample flow are obtained. The simulation results are consistent with theoretical outcomes. And preliminary experiments were carried out to prove the simulation results.

Pulsed Injector Induced Mixing in High Aspect Ratio Microchannel Flow

2003 ◽  
Author(s):  
B. Siripoorikan ◽  
J. A. Liburdy ◽  
D. V. Pence
Keyword(s):  
Aspect Ratio ◽  
Flow Rate ◽  
High Aspect Ratio ◽  
Rate Ratio ◽  
Main Channel ◽  
Flow Rate Ratio ◽  
Passive Mixing ◽  
Mixing Techniques ◽  
Biochemical Production ◽  
High Degree

Micro-fluid mixing is an important aspect of many of the various micro-fluidic systems used in biochemical production, biomedical industries, microenergy systems and some electronic devices. Active or highly effective passive mixing techniques are often required. In this study, two pulsed injectors are used to actively enhance mixing in a high aspect ratio microchannel (125 μm deep and 1 mm wide). The main channel has two adjacent flowing streams with 100% dye and 0% dye concentrations, respectively. Two injectors (125 μm deep and 250 μm wide) are located on opposite sides of the channel and off-set in the downstream direction. A dye solution is used to map local mixing throughout the channel by measuring concentration variations as a function of both space and time. Images of the concentration variations within the channel are used to quantify mixing. It is shown that there is a high degree of repeatability of concentration distribution as a function of phase of the pulsing cycle. The flow rate ratio between the injectors and main channel is found to be the most influential parameter on overall mixing, and evidence of an optimal flow rate ratio and frequency is presented. A nondimensional correlation is presented that could be used to predict the level of mixing for the conditions studied.

scholarly journals Integration of a Dielectrophoretic Tapered Aluminum Microelectrode Array with a Flow Focusing Technique

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4957
Author(s):  
Naqib Fuad Abd Rashid ◽  
Revathy Deivasigamani ◽  
M. F. Mohd Razip Wee ◽  
Azrul Azlan Hamzah ◽  
Muhamad Ramdzan Buyong
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Microelectrode Array ◽  
Flow Simulation ◽  
Optimization Method ◽  
Micro Milling ◽  
Flow Rate Ratio ◽  
Flow Focusing ◽  
Focusing Effect ◽  
Polystyrene Beads

We present the integration of a flow focusing microfluidic device in a dielectrophoretic application that based on a tapered aluminum microelectrode array (TAMA). The characterization and optimization method of microfluidic geometry performs the hydrodynamic flow focusing on the channel. The sample fluids are hydrodynamically focused into the region of interest (ROI) where the dielectrophoresis force (FDEP) is dominant. The device geometry is designed using 3D CAD software and fabricated using the micro-milling process combined with soft lithography using PDMS. The flow simulation is achieved using COMSOL Multiphysics 5.5 to study the effect of the flow rate ratio between the sample fluids (Q1) and the sheath fluids (Q2) toward the width of flow focusing. Five different flow rate ratios (Q1/Q2) are recorded in this experiment, which are 0.2, 0.4, 0.6, 0.8 and 1.0. The width of flow focusing is increased linearly with the flow rate ratio (Q1/Q2) for both the simulation and the experiment. At the highest flow rate ratio (Q1/Q2 = 1), the width of flow focusing is obtained at 638.66 µm and at the lowest flow rate ratio (Q1/Q2 = 0.2), the width of flow focusing is obtained at 226.03 µm. As a result, the flow focusing effect is able to reduce the dispersion of the particles in the microelectrode from 2000 µm to 226.03 µm toward the ROI. The significance of flow focusing on the separation of particles is studied using 10 and 1 µm polystyrene beads by applying a non-uniform electrical field to the TAMA at 10 VPP, 150 kHz. Ultimately, we are able to manipulate the trajectories of two different types of particles in the channel. For further validation, the focusing of 3.2 µm polystyrene beads within the dominant FDEP results in an enhanced manipulation efficiency from 20% to 80% in the ROI.

scholarly journals Concentration profiles of ions and particles under hydrodynamic focusing in Y-shaped square microchannel

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Norikazu Sato ◽  
Daisuke Kawashima ◽  
Masahiro Takei
Keyword(s):  
Reynolds Number ◽  
Flow Rate ◽  
Rate Ratio ◽  
Flow Direction ◽  
Ion Concentration ◽  
Flow Rate Ratio ◽  
Hydrodynamic Focusing ◽  
Cross Sectional ◽  
Particle Stream ◽  
Square Microchannel

AbstractThree-dimensional ion and particle concentrations under hydrodynamic focusing in a Y-shaped square microchannel are numerically simulated to clarify the decrease of the ion concentration along the flow direction within the focused particle stream. The simulation model is theoretically governed by the laminar flow and advection–diffusion equations. The governing equations are solved by the finite volume method. The ion and particle concentration distributions at five cross sections after the confluence of the branch channels are analyzed in 30 cases in which the sheath to sample flow rate ratio Qsh/Qsam and the Reynolds number Re are varied as parameters. The results show that the decrease of the cross-sectional average ion concentration along the flow direction within the particle stream $$\overline{c}_{i}$$ c ¯ i is described by the diffusion length during the residence time with a characteristic velocity scale. In addition, the deformation of the particle stream due to inertial effects is described by a scaled Reynolds number that is a function of the flow rate ratio. The simulated particle stream thicknesses are validated by theory and a simple experiment. This paper reveals the relationship between the ion and particle concentrations and the dimensionless parameters for hydrodynamic focusing in the Y-shaped square microchannel under typical conditions.

Determination of flow rate ratio for plate valve operating in two-phase medium

1989 ◽  
Vol 25 (7) ◽  
pp. 394-396
Author(s):  
V. E. Shcherba ◽  
I. S. Berezin ◽  
S. S. Danilenko ◽  
I. E. Titov ◽  
P. P. Filippov
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Flow Rate Ratio ◽  
Two Phase ◽  
Plate Valve ◽  
Phase Medium

Effect of the argon/monomer flow-rate ratio on the flowability trend of PECVD-processed micropowder

2017 ◽  
Vol 328 ◽  
pp. 480-487 ◽  
Author(s):  
V.R. Giampietro ◽  
M. Gulas ◽  
P. Rudolf von Rohr
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Flow Rate Ratio

Effects of Respiration and Gravity on Infradiaphragmatic Venous Flow in Normal and Fontan Patients

Circulation ◽  
2000 ◽  
Vol 102 (suppl_3) ◽  
Author(s):  
Tain-Yen Hsia ◽  
Sachin Khambadkone ◽  
Andrew N. Redington ◽  
Francesco Migliavacca ◽  
John E. Deanfield ◽  
...  
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Venous Return ◽  
Fontan Circulation ◽  
Flow Rate Ratio ◽  
Venous Flow ◽  
Beneficial Effects ◽  
In Series ◽  
Expiratory Flow ◽  
Fontan Patients

Background —In the Fontan circulation, pulmonary and systemic vascular resistances are in series. The implications of this unique arrangement on infradiaphragmatic venous physiology are poorly understood. Methods and Results —We studied the effects of respiration and gravity on infradiaphragmatic venous flows in 20 normal healthy volunteers (control) and 48 Fontan patients (atriopulmonary connection [APC] n=15, total cavopulmonary connection [TCPC] n=30). Hepatic venous (HV), subhepatic inferior vena caval (IVC), and portal venous (PV) flow rates were measured with Doppler ultrasonography during inspiration and expiration in both the supine and upright positions. The inspiratory-to-expiratory flow rate ratio was calculated to reflect the effect of respiration, and the supine-to-upright flow rate ratio was calculated to assess the effect of gravity. HV flow depended heavily on inspiration in TCPC compared with both control and APC subjects (inspiratory-to-expiratory flow rate ratio 3.4, 1.7, and 1.6, respectively; P <0.0001). Normal PV flow was higher in expiration, but this effect was lost in TCPC and APC patients (inspiratory-to-expiratory flow rate ratio 0.8, 1.0, and 1.1, respectively; P =0.01). The respiratory influence on IVC flow was the same in all groups. Gravity decreased HV flow more in APC than in TCPC patients (supine-to-upright flow rate ratio 3.2 versus 2.1, respectively; P <0.04) but reduced PV flow equally in all groups. Conclusions —Gravity and respiration have important influences on infradiaphragmatic venous return in Fontan patients. Although gravity exerts a significant detrimental effect on lower body venous return, which is more marked in APC than in TCPC patients, the beneficial effects of respiration in TCPC patients are mediated primarily by an increase in HV flow. These effects may have important short- and long-term implications for the hemodynamics of the Fontan circulation.

scholarly journals Numerical and experimental investigation on the depressurization capacity of a new type of depressure-dominated jet mill bit

2020 ◽  
Vol 17 (6) ◽  
pp. 1602-1615
Author(s):  
Xu-Yue Chen ◽  
Tong Cao ◽  
Kai-An Yu ◽  
De-Li Gao ◽  
Jin Yang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Area Ratio ◽  
Low Flow ◽  
Flow Rate Ratio ◽  
Cuttings Transport ◽  
Horizontal Drilling ◽  
Hole Cleaning ◽  
Bottom Hole ◽  
New Type

AbstractEfficient cuttings transport and improving rate of penetration (ROP) are two major challenges in horizontal drilling and extended reach drilling. A type of jet mill bit (JMB) may provide an opportunity to catch the two birds with one stone: not only enhancing cuttings transport efficiency but also improving ROP by depressuring at the bottom hole. In this paper, the JMB is further improved and a new type of depressure-dominated JMB is presented; meanwhile, the depressurization capacity of the depressure-dominated JMB is investigated by numerical simulation and experiment. The numerical study shows that low flow-rate ratio helps to enhance the depressurization capacity of the depressure-dominated JMB; for both depressurization and bottom hole cleaning concern, the flow-rate ratio is suggested to be set at approximately 1:1. With all other parameter values being constant, lower dimensionless nozzle-to-throat-area ratio may result in higher depressurization capacity and better bottom hole cleaning, and the optimal dimensionless nozzle-to-throat-area ratio is at approximately 0.15. Experiments also indicate that reducing the dimensionless flow-rate ratio may help to increase the depressurization capacity of the depressure-dominated JMB. This work provides drilling engineers with a promising tool to improve ROP.

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