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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

SELF-ASSEMBLED STABLE CLUSTERS OF DROPLETS OVER THE LOCALLY HEATED WATER SURFACE: MILESTONES OF THE LABORATORY STUDY

Get access (open in a dialog) DOI: 10.1615/IHTC16.kn.000002
pages 65-72

Resumo

The self-assembled clusters of regularly positioned small droplets are formed over the locally heated water surface. This phenomenon was observed for the first time by Alexander Fedorets in 2004. The behavior of levitating droplet clusters in the upcoming gas flow has been studied in detail. The life cycle of clusters from the baby-droplet to the coalescence of heavy droplets with substrate layer of water is quite clear now. In 2015, the first milestone of the work has been reached and we transferred from passive observations to managing the process. The main objective was to stabilize the clusters and avoid their coalescence with water substrate. This was achieved by relatively weak infrared heating of droplets. An alternative way to decrease significantly the rate of droplet growth with the use of a periodic variation of the heating laser power is also analyzed. The optimum period of the power variation is experimentally determined. The problem of generation of droplet clusters in the desired temperature range for the upcoming studies of biochemical processes was solved with the use of a strong cooling of both water layer and ambient air. Life goes on, and we are now at the second milestone. The new stage of the work on entropy analysis of ordinary and small clusters has been recently started in a cooperation with our colleagues from Israel and USA. The work on formation of droplet clusters with the controlled amount of admixtures in water is also in progress now. An additional laboratory equipment with Raman spectroscopy of single droplets will enable us to leave behind the next milestone and begin the study of biochemical processes in the droplets.