| Autor: |
Fedorets AA; X-BIO Institute, University of Tyumen, 6 Volodarskogo St., Tyumen 625003, Russia., Dombrovsky LA; X-BIO Institute, University of Tyumen, 6 Volodarskogo St., Tyumen 625003, Russia.; Heat Transfer Department, Joint Institute for High Temperatures, 17A Krasnokazarmennaya St., Moscow 111116, Russia.; Department of Chemical Engineering, Faculty of Engineering, Ariel University, Ariel 407000, Israel., Bormashenko E; Department of Chemical Engineering, Faculty of Engineering, Ariel University, Ariel 407000, Israel., Frenkel M; Department of Chemical Engineering, Faculty of Engineering, Ariel University, Ariel 407000, Israel., Nosonovsky M; X-BIO Institute, University of Tyumen, 6 Volodarskogo St., Tyumen 625003, Russia.; Department of Chemical Engineering, Faculty of Engineering, Ariel University, Ariel 407000, Israel.; Department of Mechanical Engineering, University of Wisconsin─Milwaukee, 3200 North Cramer St., Milwaukee, Wisconsin 53211, United States. |
| Abstrakt: |
Self-assembled microdroplet clusters can levitate above a locally heated water surface. Normally, the temperature of droplets is in the range of 50-95 °C. However, it is possible to generate clusters at lower temperatures. Here, we study the structure and behavior of such cold-stabilized droplet clusters with variable temperature. It has been established that as the temperature decreases, the role of aerodynamic forces decreases, while electrostatic forces, on the contrary, increase. We studied the behavior of droplet clusters at relatively low temperatures down to 28 °C. A chaotic motion of droplets and a phase transition were observed at the surface temperature of the water below a critical value of about T max = 35 ± 2 °C. The orderliness of the cluster was quantified with the Shannon/Voronoi entropy. Several stages of cluster evolution were observed and analyzed, and a mechanism of this phenomenon is discussed. An inverse phase transition in which cooling of the cluster decreases its orderliness is discussed. Frequencies of the droplets' oscillations coincide qualitatively with the frequency of the plasma oscillations within the cluster. |
