This research work represents an experimental study of the interaction between water drops deposited on a substrate at ambient temperature. To examine this phenomenon, the evaporation of a single drop deposited on a substrate was first investigated. Then, several drops were deposited alongside on the same substrate under the same conditions. The central drop dynamic behavior was also examined and compared with that of a single drop. This comparison shows the effect of the interaction between the neighboring drops, which delayed the evaporation of these drops and particularly the central droplet, on evaporation. In fact, three configurations were studied by changing the initial distance, d, between the drops (d = 0.2 mm, d = 7 mm, and d = 15 mm). The obtained results reveal that the interaction phenomenon becomes less important by increasing the distance between the drops. This is important for optimizing many industrial applications, such as spray drying, fuel injection in combustion engines, and other applications.

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The evaporation of a drop deposited on a heated substrate is a complex process, which combines several phenomena such as the Marangoni effect, mass and thermal transfers, etc. We developed, in this paper, a mathematical model and a numerical simulation code used to carry out an in-depth study about the evaporation of a drop deposited on a heated substrate surrounded by air. This numerical study was supported by experimental work. The numerical findings obtained showed the existence of a condensation phenomenon for certain configurations. At the beginning of the experiment, the evaporation started at the triple point. However, a local region of the interface remained relatively cold. In this region, the concentration gradient (C v , C sat) directed from the liquid-gas interface to the air resulted in condensation of water steam. Although this phenomenon is temporary and visible only at the start of evaporation process, its study makes it possible to better understand and optimize the evaporation kinetics.