Droplet motion is important in discrete microfluidic operations as well as in emerging site-specific cooling techniques based on electrowetting. The present work reports on carefully characterized experiments that map the shape, advancing and receding contact angles, and contact area of droplets sliding under gravitational actuation as a function of droplet size and velocity. A pseudo-Lagrangia...

The objective of this research is to develop an accurate numerical method to be used in showing the deformation of a liquid fuel droplet in a convective field. To simultaneously solve the internal liquid droplet flow field as well as the external gas phase flow field, a nonstaggered rectangular grid system without any coordinate transformation is used. Transition from the gas field to the liqui...

Two optical methods, light absorption and LDA, are applied to measure the concentration and velocity profiles of droplet suspensions flowing through a tube. The droplet concentration is non-uniform and has two maxima, one near the tube wall and one on the tube axis. The measured velocity profiles are blunted, but a central plug-flow region is not observed. The concentration of droplets on the t...

The motion of droplets on surfaces is crucial to the performance of a wide range of processes; this study examines the initiation of droplet motion through a shearing mechanism generated here by a controlled air flow. Systematic experiments are carried out for a range of fluids and well defined surfaces. A model is postulated that balances surface tension forces at the contact line and the drag...

The extinction of an envelope flame at the forward stagnation point of a liquid fuel droplet due to forced convection is numerically investigated. The droplet is oxidizing within an air stream at atmospheric pressure. Combustion is modeled using finite-rate chemical kinetics and a one-step overall reaction. The gas-phase solution is obtained using the quasi-steady equations of mass, momentum, s...

This paper describes and characterizes the electrowetting-induced movement of droplets in an immiscible medium. When an aqueous droplet undergoes electrowetting-induced motion in a continuous phase of olive oil, the droplet glides through the olive oil at a much higher velocity than is possible in the absence of oil and is able to travel greater than 10 times the electrode separation distance. ...

0894-1777/$ see front matter 2012 Elsevier Inc. A doi:10.1016/j.expthermflusci.2012.01.031 ⇑ Corresponding author. Tel.: +1 513 529 0718; fax E-mail address: [email protected] (A.D. Som 1 Tel.: +1 513 529 1933; fax: +1 513 529 5629. Air-flow induced water droplet movement on micro-patterned aluminum surfaces consisting of parallel grooves tens of microns in width and depth is considered, and ...

We show that very low velocity droplets can be used to carry out an experiment to test whether condensate mediated transmission processes can occur in a superfluid droplet of He. By appropriately choosing the droplet radius and temperature, we can eliminate the competing roton, phonon, and ripplon mediated elastic transmission events. Then a calculation shows that if a few percent or more of th...

Liquid agent transport was investigated around unheated and heated horizontal cylinders (to a near-surface temperature of approximately 423 K, i.e., well above the water boiling point) under ambient conditions. Experimental results are presented for a well-characterized, droplet-laden homogenous turbulent flow field, using water, methoxy-nonafluorobutane (i.e., HFE-7100, C4F9OCH3, with a boilin...

Disclaimer: The findings and conclusions in this article are those of the authors, and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Water spray characteristics, including droplet size and velocity, airborne dust capture potential, and induced airflow quantity for various spray nozzle designs were evaluated to provide basic information for ...