Micro PIV measurement of two-fluid flow with different refractive indices

Kim, Byoung Jae; Yz, Liu; Sung, Hyung Jin

doi:10.1088/0957-0233/15/6/008

Cited by 42 publications

(31 citation statements)

References 16 publications

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“…This technique has been widely utilized since it is proposed in 1998 (Santiago et al 1998). For example, the measurements of blood flow (Park et al (Kim et al 2004), counter current flow (Shinohara et al 2004), and flow field in a fluidic oscillator (Yang et al 2006) have all been obtained using this method. In addition, the data of the velocity vectors can also be used to evaluate the pressure fields in laminar channel flows by solving the Poisson equation (Fujisawa et al 2006).…”

Section: Motivations and Objectivesmentioning

confidence: 99%

Unsteady flow behaviors in an obstacle-type valveless micropump by micro-PIV

Sheen

Hsu

et al. 2007

Microfluid Nanofluid

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In this paper, a PZT micropump excited by amplified squarewave signals with various frequencies was used to study the transient flow behaviors in an obstacletype valveless micropump. A micro-particle-image-velocimetry (micro-PIV) with an external trigger was developed to obtain flow fields at the outlet and around the obstacle with various phases in a cycle. In comparison with previous studies on the pump performance, such as pump pressure and volume flow rate, more detailed information about the pump was obtained. The velocity profiles and periodic sectional mean velocities exhibited the unsteady flow nature. The total net flow generation efficiency per cycle was obtained experimentally by integrating the phase-dependent velocities. The flow recirculation around the obstacle was observed and quantified to investigate the influence on the pump performance. The duration, circulation, and the size of the recirculation regions indicated that this flow behavior could enhance the flow-directing capability. These results are very useful for the design and improvement of obstacle-type valveless micropumps. Keywords Valveless micropump Á Externally triggered micro-PIV Á Micro oscillating flow Á Flow recirculation List of symbols A o Area of grid cell (mm 2 ) d Diameter of a glass tube d p Diameter of seeding particle (lm) D f Diffusion coefficient (m 2 /s) h Height of liquid in a glass tube I Fluid inductance (Pa s 2 /m 3 ) n Radial oscillating frequency n o Refraction ratio NA Numerical aperturê Q Volume of flow rate (m 3 /s) r Characteristic length of channel (lm) R Flow resistance (Pa s/m 3 ) t Specific time in a time period (s) t r Response time of tracer particle (s) T Time of a period (s) u i Velocity in x or y direction (mm/s) U o Maximum velocity at each velocity profile (mm/s) Wo Womersley number Y o Channel width (lm) Z Complex form of flow impedance (Pa s/m 3 )Greek alphabets dz o Depth of correlation (lm) DP Complex form of pressure drop (Pa) DtTime interval between the laser pulses (s) e i Errors due to Brownian motion G Circulation (mm 2 /s) gThe flow-directing efficiency of a valveless flow rectifier g o Flow rate ratio of pump/supply

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Section: Motivations and Objectivesmentioning

confidence: 99%

Unsteady flow behaviors in an obstacle-type valveless micropump by micro-PIV

Sheen

Hsu

et al. 2007

Microfluid Nanofluid

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“…The standard Smoluchowski approach with Debye Huckel linear approximation under low zeta potential (ψ < 25 mV) has been pro-posed to predict the velocity field of EO driven flow 8,13,[15][16][17] . Measurement methods, such as current monitoring and microparticle image velocimetry (micro-PIV), were introduced and utilized to determine velocity field of EO driven flow [18][19][20][21][22][23] . These theoretical predictions have been proven to accurately model the experimental measurements.…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical investigations of non-Newtonian electro-osmotic driven flow in rectangular microchannels

et al. 2016

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With the development of microfluidics, electro-osmotic (EO) driven flow has gained intense research interest as a result of its unique flow profile and the corresponding benefits in its application in the transportation of sensitive samples. Sensitive samples, such as DNA, are incapable of enduring strong flow shear induced by conventional hydrodynamic driven methods. EO driven flow is thus a niche area. However, even though there are a few research studies focusing on bio-fluidic samples related to EO driven flow, the majority of them are merely theoretical modeling without solid evidence from experiments due to the inherent complex rheological behavior of the bio-fluids. Challenges occur when the EO driven mechanism meets with complex rheology; vital questions such as can the zeta potential still be assumed to be constant when dealing with fluids with complex rheology? and "Does the shear thinning effect enhance electro-osmotic driven flow?" need to be answered. We conducted experiments using current monitoring and microscopy fluorescence methods, and developed a theoretical model by coupling a generalized Smoluchowski approach with the power-law constitutive model. We calculated the zeta potential and compared the experimental results with modeling to answer the questions. The results show a reduction of zeta potential in the presence of PEO aqueous solutions. A constant zeta potential is also indicated by varying the PEO concentration and the electric field strength.The shear thinning effect is also addressed via experimental data and theoretical calculations. The results show a promising enhancement of the EO driven velocity due to the shear thinning effect.

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“…During the last decade, the micro-PIV technique has been applied to various microscale flows such as a pressuredriven flow inside a microfabricated inkjet head (Meinhart and Zhang 2000), electrokinetic flow (Cummings 2000), electro-osmosis-driven microchannel flows (Kim et al 2002), flows with apparent slip velocity Meinhart 2002, 2004), two-fluid flow with different refractive indices (Kim et al 2004), and transient flow in microfluidic devices (Shinohara et al 2004). …”

Section: Introductionmentioning

confidence: 99%