High temperature nonisothermal desorption in a water–salt droplet

•Experimental data on dynamics of nucleate boiling in the droplets of LiBr water solution were obtained.•Kinetics of the bubble growth is mainly characterizes by the surface Marangoni flow.•The Marangoni force is determined by a significant longitudinal gradient of salt concentration.•At high crystallization rates the different crystalline-hydrate structures are formed.

Experimental data on dynamics of nucleate boiling in the droplets of LiBr water solution were obtained. Time dependences for a change in bubble geometry were determined and characteristic desorption regimes were distinguished. The rate of bubble growth decreases with a rise in salt concentration and boiling stops completely at high concentration of LiBr. An increase in salt concentration in a liquid layer of the bubble bottom leads to a considerable decrease in the rate of desorption, and the rate of bubble diameter increase decreases significantly, and a dry spot is not formed. The growth features of the crystalline-hydrate film depend on the rate of crystallization. Thermal measurements were carried out by means of thermal imager lenses with ten-fold magnification. The video and thermal recording allowed us to distinguish the self-organized crystalline-hydrate structures at high crystallization rates: rod-like, dendrite, and dome-shaped ones. Complex morphology of these structures promotes an increase in the rate of water desorption from the surface of crystalline-hydrate film.