A method for simultaneously determining the zeta potentials of the channel surface and the tracer particles using microparticle image velocimetry technique

A pressure resistant and optically accessible deterministic lateral displacement (DLD) device was designed and microfabricated from silicon and glass for high-throughput fractionation of particles between 3.0 and 7.0 µm comprising array segments of varying tilt angles with a post size of 5 µm. The design was supported by computational fluid dynamic (CFD) simulations using OpenFOAM software. Simulations indicated a change in the critical particle diameter for fractionation at higher Reynolds numbers. This was experimentally confirmed by microparticle image velocimetry (µPIV) in the DLD device with tracer particles of 0.86 µm. At Reynolds numbers above 8 an asymmetric flow field pattern between posts could be observed. Furthermore, the new DLD device allowed successful fractionation of 2 µm and 5 µm fluorescent polystyrene particles at Re = 0.5–25.

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Experimental investigation of bubble formation and motion mechanism near the moonpool

Proceedings of the Institution of Mechanical Engineers Part M Journal of Engineering for the Maritime Environment ◽

10.1177/14750902211044962 ◽

2021 ◽

pp. 147509022110449

Author(s):

Xiongliang Yao ◽

Xianghong Huang ◽

Zeyu Shi ◽

Wei Xiao ◽

Kainan Huang

Keyword(s):

High Speed ◽

Bubble Formation ◽

Similarity Criteria ◽

Dominant Factor ◽

Acoustic Detection ◽

Prototype Test ◽

Tracer Particles ◽

Research Ship ◽

Image Velocimetry ◽

Ventilation Method

When a research ship sails at a high speed, there is relative motion between the ship and fluid. The ship is slammed by the fluid. To reduce the direct impact of the fluid, sonar is installed in the moonpool, and acoustic detection equipment is installed along the research ship bottom behind the moonpool. However, during high-speed sailing, a large number of bubbles form in the moonpool. Some bubbles escape from the moonpool and flow backward along the bottom of the ship. When a large number of bubbles are around the sonar and acoustic detection equipment, the equipment malfunctions. However, there have been few studies on bubble formation in the moonpool with sonar and distribution along the ship bottom behind the moonpool. Therefore, a related model was developed and prototype tests were carried out in this study. The appropriate similarity criteria were selected and verified to ensure the reliability of the experiment. Considering the influences of speed, sonar, moonpool shape, and draft, the reason and mechanism of bubble formation in a sonar moonpool were studied. An artificial ventilation method was used to simulate a real navigation environment. Because the bubbles are in a bright state under laser irradiation, the bubbles can be used as tracer particles. A high-speed camera captured illuminated bubbles. The distribution mechanism of bubbles along the ship bottom behind the moonpool was investigated using particle image velocimetry under the influence of the moonpool shape and sailing speed. The model experimental results agreed well with those of the prototype test. The air sucked into the water was the dominant factor in bubble formation in the moonpool. The bubbles were distributed in a W shape under the ship bottom.

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Measurement of Air Flow Outside a Burning Cigarette during a Puff using Particle Image Velocimetry

Beiträge zur Tabakforschung International/Contributions to Tobacco Research ◽

10.2478/cttr-2013-0783 ◽

2004 ◽

Vol 21 (4) ◽

pp. 216-222

Author(s):

A Nagao ◽

K Miura ◽

S Kitao ◽

M Horio

Keyword(s):

Particle Image Velocimetry ◽

Particle Image ◽

Air Flow ◽

Maximum Velocity ◽

Flow Distribution ◽

Combustion Mechanism ◽

Air Flow Rate ◽

Tracer Particles ◽

Image Velocimetry ◽

Cigarette Paper

AbstractIn order to clarify the mechanism for the generation of cigarette smoke, the combustion mechanism of a burning cigarette during a puff was investigated by focusing on air transfer. In particular, the air flow distribution outside a burning cigarette was observed and related to the aerodynamic effects of the cigarette paper and the puffing rate. The air flow rate was measured by Particle Image Velocimetry (PIV), using olive oil droplets as the tracer particles. It was found that air does not flow into the tip of the burning cigarette and that the air flow was concentrated at the region -2 to 2 mm around the cigarette paper char-line. This behavior was independent of the cigarette paper basis weight. When the puffing rate was changed from 2.5 to 35 mL/s, the air flow was concentrated at a region close to the cigarette paper char-line and the maximum velocity around the cigarette paper char-line increased with the puffing rate.

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Resonant Mixing in Glass Bowl Microbioreactor Investigated by Microparticle Image Velocimetry

Micromachines ◽

10.3390/mi10050284 ◽

2019 ◽

Vol 10 (5) ◽

pp. 284 ◽

Cited By ~ 4

Author(s):

Sven Meinen ◽

Lasse Jannis Frey ◽

Rainer Krull ◽

Andreas Dietzel

Keyword(s):

Surface Waves ◽

Growth Conditions ◽

Capillary Surface ◽

Mixing Conditions ◽

Glass Slides ◽

Image Velocimetry ◽

Resonance Frequencies ◽

Microparticle Image Velocimetry ◽

Growing Conditions ◽

Vortex Patterns

Microbioreactors are gaining increased interest in biopharmaceutical research. Due to their decreasing size, the parallelization of multiple reactors allows for simultaneous experiments. This enables the generation of high amounts of valuable data with minimal consumption of precious pharmaceutical substances. However, in bioreactors of all scales, fast mixing represents a crucial condition. Efficient transportation of nutrients to the cells ensures good growing conditions, homogeneous environmental conditions for all cultivated cells, and therefore reproducible and valid data. For these reasons, a new type of batch microbioreactor was developed in which any moving mixer component is rendered obsolete through the utilization of capillary surface waves for homogenization. The bioreactor was fabricated in photosensitive glass and its fluid volume of up to 8 µL was provided within a bowl-shaped volume. External mechanical actuators excited capillary surface waves and stereo microparticle image velocimetry (µPIV) was used to analyze resulting convection at different excitation conditions in varied reactor geometries. Typical vortex patterns were observed at certain resonance frequencies where best mixing conditions occurred. Based on the results, a simplified 1D model which predicts resonance frequencies was evaluated. Cultivation of Escherichia coli BL21 under various mixing conditions showed that mixing in resonance increased the biomass growth rate, led to high biomass concentrations, and provided favorable growth conditions. Since glass slides containing multiple bowl reactors can be excited as a whole, massive parallelization is foreseen.

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The theory of diffraction-limited resolution in microparticle image velocimetry

Measurement Science and Technology ◽

10.1088/0957-0233/14/7/320 ◽

2003 ◽

Vol 14 (7) ◽

pp. 1047-1053 ◽

Cited By ~ 75

Author(s):

Carl D Meinhart ◽

Steven T Wereley

Keyword(s):

Image Velocimetry ◽

Microparticle Image Velocimetry

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Improvement of Micro-PIV Resolution by Selective Seeding

ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels, Parts A and B ◽

10.1115/icnmm2006-96146 ◽

2006 ◽

Cited By ~ 1

Author(s):

Michal M. Mielnik ◽

Lars R. Sætran

Keyword(s):

Optical Measurement ◽

Fluid Layer ◽

Field Measurements ◽

Time Resolved ◽

Micro Piv ◽

Tracer Particles ◽

Seeding Method ◽

Image Velocimetry ◽

Out Of Plane ◽

Measurement Depth

A novel seeding method, permitting high out-of-plane resolution and instantaneous (time-resolved) velocity field measurements using a standard Microscale Particle Image Velocimetry (micro-PIV) setup, is presented. The method relies on selective seeding of a thin fluid layer within an otherwise particle-free flow. The generated particle sheet defines the depth and position of the measurement plane, independently of the details of the optical setup. Therefore, for low magnification objectives in particular, considerable improvement in the measurement depth is possible. Selectively seeded micro-PIV (SeS-PIV) is applied to a microchannel flow, and the measured instantaneous velocity fields are in excellent agreement with the theoretical solution for the flowfield. The currently presented measurements have a depth-wise resolution 20% below the estimated optical measurement depth of the micro-PIV system. In principle, a measurement depth corresponding to the diameter of the tracer particles may be achieved.

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Flow Field Analysis of Dielectrophoretically-Suspended Particles

Volume 11: Micro and Nano Systems, Parts A and B ◽

10.1115/imece2007-41252 ◽

2007 ◽

Author(s):

Stuart J. Williams ◽

Steven T. Wereley

Keyword(s):

Electric Fields ◽

Particle Image ◽

Fluid Velocity ◽

Microfluidic Channel ◽

Velocity Fields ◽

Field Analysis ◽

Tracer Particles ◽

Image Velocimetry ◽

Flow Field Analysis ◽

Complete Investigation

Understanding the fluid dynamics around a particle in suspension is important for a complete investigation of many hydrodynamic phenomena, including microfluidic models. A novel tool that has been used to analyze fluid velocity fields in microfluidics is micro-resolution particle image velocimetry (μPIV) [1]. Dielectrophoresis (DEP) is a technique that can translate and trap particles by induced polarization in the presence of nonuniform electric fields. In this paper, DEP has been used to capture and suspend a single 10.1μm diameter spherical particle in a microfluidic channel. μPIV is then used with smaller tracer particles (0.5μm) to investigate the hydrodynamics of fluid flow past the trapped particle.

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Tuning the dispersion of reactive solute by steady and oscillatory electroosmotic–Poiseuille flows in polyelectrolyte-grafted micro/nanotubes

Journal of Fluid Mechanics ◽

10.1017/jfm.2019.628 ◽

2019 ◽

Vol 880 ◽

pp. 73-112

Author(s):

Milad Reshadi ◽

Mohammad Hassan Saidi

Keyword(s):

Hydrodynamic Dispersion ◽

Asymptotic State ◽

Late Time ◽

Band Broadening ◽

Zeta Potentials ◽

Tracer Particles ◽

Ion Partitioning ◽

Analytical Approaches ◽

Benchmark Solutions ◽

Poiseuille Flows

This paper extends the analysis of solute dispersion in electrohydrodynamic flows to the case of band broadening in polyelectrolyte-grafted (soft) capillaries by accounting for the effects of ion partitioning, irreversible catalytic reaction and pulsatile flow actuation. In the Debye–Hückel limit, we present the benchmark solutions of electric potential and velocity distribution pertinent to steady and oscillatory mixed electroosmotic–pressure-driven flows in soft capillaries. Afterwards, the mathematical models of band broadening based on the Taylor–Aris theory and generalized dispersion method are presented to investigate the late-time asymptotic state and all-time evolution of hydrodynamic dispersion, respectively. Also, to determine the heterogeneous dispersion behaviour of solute through all spatiotemporal stages and to relax the constraint of small zeta potentials, a full-scale numerical simulation of time-dependent solute transport in soft capillaries is presented by employing the second-order-accurate finite difference method. Then, by inspecting the dispersion of passive tracer particles in Poiseuille flows, we examine the accuracy of two analytical approaches against the simulation results of a custom-built numerical algorithm. Our findings from hydrodynamic dispersion in Poiseuille flows reveal that, compared to rigid capillaries, more time is required to approach the longitudinal normality and transverse uniformity of injected solute in soft capillaries. For the case of dispersion in mixed electrohydrodynamic flows, it is found that the characteristics of the soft interface, including the thickness, permittivity, fixed charge density and friction coefficient of the polymer coating layer, play a significant role in determining the Taylor diffusion coefficient, advection speed and dispersion rate of solutes in soft capillaries.

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