2. Outline
• Training
– Equipment/Programs
• Project
– Collecting data
• Problem Encountered
– Different sized water droplets
• Solutions
– Literature Review
– Progress
• Outlook
• References
3. Training
• Equipment
– Set-up for water droplet
experiments
– Process to begin/end an
experiment
– Lab Safety
• Programs
– Phantom Camera Control
Application (PCC 2.14)
• Taking video of water droplet
impact
• Calibrating program
measurement
• Measuring diameter, angle and
velocity of water droplet
4. Summer Project
• Study the fluid dynamics of multiple water
droplet impact
– Observe the velocity, size and spacing of the
droplets
• Also to manufacture a mechanism that creates
similar sized water droplets
5. Problem Encountered
• Two consecutive water droplets at
the surface were of different
diameters
• A difference would cause
inaccurate data or observations of
its impact
• A total of 0.4mm in diameter
difference
6. • Due to the first droplet there was an increase of bubbles within the
second droplet
• Because of the air, at the surface the 2nd drop had decreased in size
• Closer look at second droplet once released:
Problem Encountered Continued
2nd Droplet Forming 2nd Droplet Release
7. Solutions
• Literature Review
– Multiple Drop Impact onto a Dry Solid Substrate
• Mechanism: Two valves at a minimal distance apart
• Possibility: Inaccurate data due to distance between the two
impacts
– Geometrically Mediated Breakup of Drops in
Microfluidic Devices
• Mechanism: Separating droplets within a tube before release
• Possibility: Was more for “micro” level study
– Numerical Simulations and Experimental
Characterization of Heat Transfer From a Periodic
Impingement of Droplets
• Mechanism: Piezoelectric droplet generator
• Possibility: Tried using a speaker emitting a high frequency, but
speaker was too small
8. Solutions Continued
• Progress
– Tried using a speaker, but the speaker was too small.
– Decided to fabricate own mechanism
– Droplet Chopper
• A mechanical system:
– Will form droplets using a disk spinning at a certain velocity
– Control over the spacing between each droplet
• Designs are created on paper, as well as a Solidworks model.
• Thus far have begun creating the motor set-up and interchangeable disc locking
mechanism
• Motor has been tested and is controllable, steadily, from a voltage of 1.2V to 2.61V
10. Outlook
• Will continue working on droplet chopper
– Will attach slicing disk
– Test mechanism
• Begin taking videos/data of multiple droplet
impacts
• Observe videos/data
11. References
Link, D. R., S. L. Anna, D. A. Weitz, and H. A. Stone. "Geometrically
Mediated Breakup of Drops in Microfluidic Devices.“
Roisman, I.V., B. Prunet-Foch, C. Tropea, and M. Vignes-Adler. "Multiple
Drop Impact onto a Dry Solid Substrate." Journal of Colloid and Interface
Science
Trujillo, Mario F., Jorge Alvarado, Eelco Gehring, and Guillermo S. Soriano.
"Numerical Simulations and Experimental Characterization of Heat
Transfer From a Periodic Impingement of Droplets."
