Effect of slippage on the thermocapillary migration of a small droplet

Nguyen, Huy Bich; Chen, Jyh Chen

doi:10.1063/1.3644382

Cited by 10 publications

(3 citation statements)

References 36 publications

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“…The actuation velocity of the liquid droplet first increases significantly, and then decreases dramatically. According to Nguyen and Chen [21][22][23] , the actuation of the behavior of the droplet depends on the net momentum of thermocapillary convection created inside the droplet. The Marangoni number (Ma) represents the strength of thermocapillary convection, which is proportional to the temperature difference inside the droplet.…”

Section: Si3mentioning

confidence: 99%

Numerical investigation of the thermocapillary migration of a water droplet in a microchannel by applying a heat source

Long

Chen

Nguyen

2020

Sci. Tech. Dev. J.- Eng. Tech.

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The migration of a small droplet has been developed during the last two decades due to its applications in industry and high technology such as MEMS and NEMS devices, Lap-On-a- chip, transportation of fluids and so on. There have many studies on this topic in which the energy source as a driving force for the moving of a droplet is quite a difference like heating, magnetics, pressure, electric, laser, and so on. In this study, the numerical computation is used to investigate the transient thermocapillary migration of a water droplet in a micro-channel under the effect of heating source. For tracking the evolution of the free interface between two immiscible fluids, we employed the finite element method with the two-phase level set technique to solve the Navier-Stokes equations and continuity equation coupled with the energy equation. Both the upper wall and the bottom wall of the microchannel are set to be ambient temperature. 40mW heat source is placed at a distance of 1 mm from the initial position of a water droplet. When the heat source is turned on, a pair of asymmetric thermocapillary convection vortices is formed inside the droplet, and the thermocapillary on the receding side is smaller than that on the advancing side. The temperature gradient inside the droplet increases quickly at the initial times and then decreases versus time. Therefore, the actuation velocity of the water droplet first increases significantly and then decreases continuously. Furthermore, the results also indicate that the dynamic contact angle is strongly affected by the oil flow motion and the net thermocapillary momentum inside the droplet. The advancing contact angle is always larger than the receding contact angle during the actuation process.

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Section: Si3mentioning

confidence: 99%

Numerical investigation of the thermocapillary migration of a water droplet in a microchannel by applying a heat source

Long

Chen

Nguyen

2020

Sci. Tech. Dev. J.- Eng. Tech.

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“…In this study, the numerical computation scheme developed by Le at el. [9,10,13] and Nguyen and Chen [15][16][17] is used to explore a small droplet movement in a microchannel under heat source. The conservative level set method and the arbitrary Lagrangian Eulerian (ALE) technique are applied to trace the evolution of the free interface.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of a Small Droplet Movement in a Microchannel under Heat Source

Chen

Nguyen

2019

AMM

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In this study, the numerical computation is used to investigate the transient movement of a water droplet in a microchannel. For tracking the evolution of the free interface between two immiscible fluids, we employed the finite element method with the two-phase level set technique to solve the Navier-Stokes equations coupled with the energy equation. Both the upper wall and the bottom wall of the microchannel are set to be an ambient temperature. 40mW heat source is placed at the distance of 1 mm from the initial position of a water droplet. When the heat source is turned on, a pair of asymmetric thermocapillary convection vortices is formed inside the droplet and the thermocapillary on the receding side is smaller than that on the advancing side. The temperature gradient inside the droplet increases quickly at the initial times and then decreases versus time. Therefore, the actuation velocity of the water droplet first increases significantly, and then decreases continuously. The dynamic contact angle is strongly affected by the oil flow motion and the net thermocapillary momentum inside the droplet. The advancing contact angle is always larger than the receding contact angle during actuation process.

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“…It was a successful conference providing a highly interactive forum that brought together approximately 200 researchers of different disciplines from more than 20 different countries and regions. This special issue is dedicated to the original contributions that were presented at the conference and covers a wide range of research directions from both fundamental and practical application of microfluidics and nanofluidics, including acoustofluidics, 1,2 biosensor 3 and diagnosis, 4 dielectrophorsis, 5-7 droplet microfluidics, [8][9][10][11][12][13][14][15] electrokinetic flow 16,17 and electrophoresis, 18 micro-and nanofabrications, [19][20][21] as well as surface modification. 22 Beginning with acoustofluidics, Wang, Jalikop, and Hilgenfeldt 1 reported a bubble microfluidic device to filter, enrich, and preconcentrate particles of selected sizes through oscillating microbubbles of radius 20-100 lm driven by ultrasound.…”

mentioning

confidence: 99%