RESUMO
A thin-sheet splash of a droplet impact on a solid surface typically appears as secondary droplets are ejected from a levitated liquid lamella. A recent work (Qin, M.; Tang, C.; Guo, Y.; Zhang, P.; Huang, Z., Langmuir 2020, 36 (18), 4917-4922) identified three subpatterns of a thin-sheet splash on a smooth wall at room temperature (T0). In the present work concerning the high-temperature (TW) surface, we show that subpatterns of the thin-sheet splash can be unified in the three-dimensional phase diagram of Oh-We-TW, where Oh is the Ohnesorge number and We is the Weber number. As TW is sufficiently high, the Leidenfrost effect becomes so prominent that both deposition and thin-sheet splash make a transition to Leidenfrost breakup. For the transition surface temperature TW,cr from thin-sheet splash to deposition, a scaling correlation of TW,cr/T0 â¼ We3/2 is derived based on the analysis of the temperature-dependent destabilizing force on the levitated lamella and agrees well with our experimental data.
RESUMO
When a droplet impacts a smooth solid surface with a sufficiently high inertia, a thin sheet is created and the whole droplet fluid then breaks apart. Latka, A. [Thin-sheet creation and threshold pressures in drop splashing. Soft Matter 2017, 13, 740-747] defined it as thin-sheet splash. In this work, we used a high-speed camera with a long-distance microscope and experimentally showed that thin-sheet splash can be subdivided into three distinct patterns in terms of breakup location. Specifically, pattern 1 is characterized by the breakup of the rim with the thin sheet being intact, pattern 2 by the almost simultaneous breakup of both the rim and the thin sheet, and pattern 3 by the breakup of the thin sheet followed by the breakup of the rim. The effects of the Weber number and the Ohnesorge number on the transitions of these subpatterns were determined over large ranges of their values, and a regime nomogram in the parametric space of We-Oh was obtained.
