Visualization

In an effort to understand the fundamental aspects of boiling phenomena, and of wettability and wickability, over the years researchers at the Micro-scale Heat Transfer Laboratory have taken many videos, including high speed videos (up to 4400 frames per second).   Below are links to these videos.

Wicking & Wetting
Water sessile drop, from deposition to static equilibrium, on a plain copper surface
Water sessile drop on, and subsequent wicking into, a microporous coating (~150 micron thick)
Highly dynamic behavior of water sessile drop induced by short distance between needle tip and highly wettable/wickable microporous coating (~150 micron thick)
Water sessile drop, from deposition to static equilibrium, showing increase in wettability (a lower static contact angle) on a nanoporous coating
Wickability of Al-HTCMC (microporous brazed coating for aluminum) in vertical dipping into a pool of water
Effect of nanoporous coating on wettability of 1 mm high copper pin fins (video), compared to wettability of uncoated copper pin fins (video)
Effect of superhydrophilic coating on wettability in 1 mm wide x 40 mm long aluminum channels (video), compared to wettability in uncoated aluminum channels (video)
Effect of superhydrophilic coating on vertical wicking in 1 mm wide x 40 mm long aluminum channels (video), compared to wickability of uncoated channels (video)

 

Pool Boiling
Simultaneous pool boiling of plain and microporous surfaces, showing earlier onset of nucleate boiling in the microporous side of the heater
Single bubble dynamics over a 1 cm x 1 cm flat copper heater in a nanofluid, heat flux of 4 W/m2, bubble diameter ~3 mm, departure frequency ~27 Hz
Ordered and Chaotic Bubble Departure Behavior During Film Boiling  (Pictures)
A Numerical Comparison of Experimental Film Boiling Characteristics (Pictures)
Nucleate and Film Boiling from a Plain, 75-µm Platinum Wire in Saturated FC-72 at Atmospheric Pressure (Videos)
Boiling from a Half-Coated,  510-µm Nichrome Wire in Saturated FC-72 at Atmospheric Pressure (Videos)

 

Flow Boiling
FC-72 flowing over a 1 cm x 1 cm TCMC coated heater in a 1 cm wide, 3 mm high channel, 20 cm from the inlet, at velocity and power inputs of:
1 m/sec, 20 W/cm2
1 m/sec, 30 W/cm2
1 m/sec, 32 W/cm2 (CHF)
0.5 m/sec, 28 W/cm2 (CHF)


       Video on Research