ISSN Online: 2377-424X
ISBN Print: 978-1-56700-474-8
ISBN Online: 978-1-56700-473-1
International Heat Transfer Conference 16
HYDROTHERMAL WAVE CONTROL IN A STEADY STATE EVAPORATING DROPLET
Resumo
We investigate the hydrothermal waves (HTWs) in the sessile droplets under steady state evaporation on two
substrates while the substrate temperature and the supplying flow rate from the droplet bottom are kept constant.
The two substrates have the different designs: one can confine the three-phase line and the other cannot.
As the substrates are heated to reach and maintain at the predetermined surface temperatures in the experiments,
the different stable HTW patterns are exhibited distinctly on the two substrates. HTWs accumulate at
the periphery of the droplet with the confined three-phase line, while HTWs are much more extended toward
the droplet center without the confinement of the contact line. With an increase of the substrate temperature,
the stable HTW numbers increase in the droplets on both the substrates, and follow linear fitting relations with
the dimensionless factor incorporating the normalized temperature difference between the substrate and the
surroundings and the droplet aspect ratio. The HTW number in the droplet with the confined contact line is
roughly twice that in the counterpart without the confined three-phase line. It is inferred that the temperature
gradients and the droplet dimensions, influenced by the droplet three-phase line, can control HTWs.