Automation and flow control for particle manipulation

Kumar, D. Sriram; Shenoy, Anish; Deutsch, Jonathan; Schroeder, Charles M.

doi:10.1016/j.coche.2020.02.006

Cited by 24 publications

(20 citation statements)

References 41 publications

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“…There were two main flow patterns of the steel particles in the high-pressure tank during the feeding process [28][29][30][31]. One was the overall flow, and all the steel particles flowed at the same time during the feeding.…”

Section: Resultsmentioning

confidence: 99%

Investigation into the Mechanism of the Steel Particle Feeding Process: A Numerical and Experimental Study

Xing

Wang³

et al. 2021

Geofluids

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The particle feeding system is a prerequisite for the realization of particle impact drilling technology. Because of the high density, the storage and flow of the steel particle are different from those of the other nonviscous particles. The differential equation of the particle movement was built with the liquid bridge force model and the discrete element method. The dynamic movement process and the distribution state of particles in the high-pressure tank were analyzed. For 1 mm steel particles, the mass flow rate decreased with the increase in water content. For 2 mm and 3 mm steel particles, the water content of 15% and 20% was the dividing point of the mass flow rate from increasing to decreasing. When the water content was 10% and 20%, the mass flow rate increased with the steel particle size. But when the water content was 30% and 40%, the mass flow rate decreased with the steel particle size. The study of the control mechanism of the uniformity and stability of particles showed that the funnel flow was the major reason causing the instability and blocking of the feeding process. This research results can provide a basis for the further improvement of the differential pressure feeding system.

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Section: Resultsmentioning

confidence: 99%

Investigation into the Mechanism of the Steel Particle Feeding Process: A Numerical and Experimental Study

Xing

Wang³

et al. 2021

Geofluids

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“…It is challenging to observe vesicle dynamics in time-dependent extensional flow for long periods of time while simultaneously imposing precisely controlled flow rates. To achieve this, we used the Stokes trap (Shenoy et al 2016;Kumar et al 2020c) to precisely position the centre-of-mass of single vesicles near the centre of a cross-slot microfluidic device for long times using model predictive control (figure 1a). Briefly, the centroid of a single vesicle is determined in real-time using image processing and fluorescence microscopy and is communicated to the controller.…”

Section: Stokes Trap For Large Amplitude Oscillatory Extensionmentioning

confidence: 99%

“…In extensional flow, fluid elements separate exponentially in time (Leal 1992), and it is generally not possible to observe a single vesicle in flow for long periods of time in the absence of feedback controllers. Automation in flow control techniques using sophisticated feedback algorithms has recently enabled the precise characterization of vesicle dynamics in elongational flows (Shenoy, Tanyeri & Schroeder 2015;Shenoy, Rao & Schroeder 2016;Shenoy et al 2019;Kumar et al 2019Kumar et al , 2020c.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we study the dynamics of single vesicles in LAOE using a combination of microfluidic experiments and boundary integral (BI) simulations. The LAOE experiments are performed using the Stokes trap (Shenoy et al 2016(Shenoy et al , 2019Kumar et al 2019Kumar et al , 2020c, which is a new method for controlling the centre-of-mass position, orientation and trajectories of freely suspended single and multiple vesicles using only fluid flow. We find that single vesicles experience periodic cycles of compression and extension in LAOE with membrane dynamics governed by the dimensionless flow strength capillary number (Ca), reduced volume (measure of vesicle asphericity, ν) and flow frequency Deborah number (De).…”

Section: Introductionmentioning

confidence: 99%

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Vesicle dynamics in large amplitude oscillatory extensional flow

et al. 2021

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Although the behaviour of fluid-filled vesicles in steady flows has been extensively studied, far less is understood regarding the shape dynamics of vesicles in time-dependent oscillatory flows. Here, we investigate the nonlinear dynamics of vesicles in large amplitude oscillatory extensional (LAOE) flows using both experiments and boundary integral (BI) simulations. Our results characterize the transient membrane deformations, dynamical regimes and stress response of vesicles in LAOE in terms of reduced volume (vesicle asphericity), capillary number ( ${Ca}$ , dimensionless flow strength) and Deborah number ( ${De}$ , dimensionless flow frequency). Results from single vesicle experiments are found to be in good agreement with BI simulations across a wide range of parameters. Our results reveal three distinct dynamical regimes based on vesicle deformation: pulsating, reorienting and symmetrical regimes. We construct phase diagrams characterizing the transition of vesicle shapes between pulsating, reorienting and symmetrical regimes within the two-dimensional Pipkin space defined by ${De}$ and ${Ca}$ . Contrary to observations on clean Newtonian droplets, vesicles do not reach a maximum length twice per strain rate cycle in the reorienting and pulsating regimes. The distinct dynamics observed in each regime result from a competition between the flow frequency, flow time scale and membrane deformation time scale. By calculating the particle stresslet, we quantify the nonlinear relationship between average vesicle stress and strain rate. Additionally, we present results on tubular vesicles that undergo shape transformation over several strain cycles. Broadly, our work provides new information regarding the transient dynamics of vesicles in time-dependent flows that directly informs bulk suspension rheology.

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“…Different technologies have their own advantages and disadvantages. The optical and magnetic tweezers have high requirements on material properties 4 . In contrast, the electrokinetic and hydrodynamic tweezers can manipulate the particle without restrictions on the material properties.…”

mentioning

confidence: 99%