On the acoustically induced fluid flow in particle separation systems employing standing surface acoustic waves – Part I

Sachs, Sebastian; Baloochi, Mostafa; Cierpka, Christian; König, Jörg

doi:10.1039/d1lc01113h

Cited by 26 publications

(23 citation statements)

References 98 publications

(174 reference statements)

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“…The displacement amplitude

is an important parameter for this work, which only influences the energy of SAW in the investigated power range. The estimation of

with the supplied electrical power

is based on the following relationship [ 35 ].

where

is the aperture of the IDTs and

is a material dependent factor.…”

Section: Experimental Set-up Materials and Methodsmentioning

confidence: 99%

Enhanced Detection in Droplet Microfluidics by Acoustic Vortex Modulation of Particle Rings and Particle Clusters via Asymmetric Propagation of Surface Acoustic Waves

Liu

et al. 2022

Biosensors

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As a basis for biometric and chemical analysis, issues of how to dilute or concentrate substances such as particles or cells to specific concentrations have long been of interest to researchers. In this study, travelling surface acoustic wave (TSAW)-based devices with three frequencies (99.1, 48.8, 20.4 MHz) have been used to capture the suspended Polystyrene (PS) microspheres of various sizes (5, 20, 40 μm) in sessile droplets, which are controlled by acoustic field-induced fluid vortex (acoustic vortex) and aggregate into clusters or rings with particles. These phenomena can be explained by the interaction of three forces, which are drag force caused by ASF, ARF caused by Leaky-SAW and varying centrifugal force. Eventually, a novel approach of free transition between the particle ring and cluster was approached via modulating the acoustic amplitude of TSAW. By this method, multilayer particles agglomerate with 20 μm wrapped around 40 μm and 20 μm wrapped around 5 μm can be obtained, which provides the possibility to dilute or concentrate the particles to a specific concentration.

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“…The displacement amplitude

is an important parameter for this work, which only influences the energy of SAW in the investigated power range. The estimation of

with the supplied electrical power

is based on the following relationship [ 35 ].

where

is the aperture of the IDTs and

is a material dependent factor.…”

Section: Experimental Set-up Materials and Methodsmentioning

confidence: 99%

Enhanced Detection in Droplet Microfluidics by Acoustic Vortex Modulation of Particle Rings and Particle Clusters via Asymmetric Propagation of Surface Acoustic Waves

Liu

et al. 2022

Biosensors

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“…As the volume flow rate was controlled in the experiment a smaller cross-section results in larger velocities. To quantitatively assess the agreement in the patterns a correlation between the experimental and simulated velocity fields was performed (for more details see Sachs et al 36 ). This analysis gives correlation coefficients 37 of ≥95% for the data of Fig.…”

Section: Discussionmentioning

confidence: 99%

Highly efficient passive Tesla valves for microfluidic applications

et al. 2022

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A multistage optimization method is developed yielding Tesla valves that are efficient even at low flow rates, characteristic, e.g., for almost all microfluidic systems, where passive valves have intrinsic advantages over active ones. We report on optimized structures that show a diodicity of up to 1.8 already at flow rates of 20 μl s−1 corresponding to a Reynolds number of 36. Centerpiece of the design is a topological optimization based on the finite element method. It is set-up to yield easy-to-fabricate valve structures with a small footprint that can be directly used in microfluidic systems. Our numerical two-dimensional optimization takes into account the finite height of the channel approximately by means of a so-called shallow-channel approximation. Based on the three-dimensionally extruded optimized designs, various test structures were fabricated using standard, widely available microsystem manufacturing techniques. The manufacturing process is described in detail since it can be used for the production of similar cost-effective microfluidic systems. For the experimentally fabricated chips, the efficiency of the different valve designs, i.e., the diodicity defined as the ratio of the measured pressure drops in backward and forward flow directions, respectively, is measured and compared to theoretical predictions obtained from full 3D calculations of the Tesla valves. Good agreement is found. In addition to the direct measurement of the diodicities, the flow profiles in the fabricated test structures are determined using a two-dimensional microscopic particle image velocimetry (μPIV) method. Again, a reasonable good agreement of the measured flow profiles with simulated predictions is observed.

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“…A detailed description on the fabrication of the microchannel using polydimethylsiloxane (PDMS) can be found in Part I. 34…”

Section: Methodsmentioning

confidence: 99%

“…Although this provides a useful guidance for the design of basic setups, a critical particle size cannot be used universally, as demonstrated in Part I of this work. 34 Furthermore, Devendran et al (2016) 35 and Fakhfouri et al (2018) 36 showed that there is an additional spatial dependence of the relative dominance between the two forces.…”

Section: Introductionmentioning

confidence: 99%