Physics

Geology

Wetting

Weber number

Reynolds number

Heat transfer

Mechanics

Oceanography

Magnet

Heat flux

Composite material

Turbulence

Dimensionless quantity

Materials science

Thermal

Substrate (aquarium)

Breakup

Computer science

Drop impact

Quantum mechanics

Drop (telecommunication)

Dewetting

Levitation

Telecommunications

Thermodynamics

Journal of Fluid Mechanics

This experimental study is focused on the mechanisms of thermal atomisation of a drop impacting onto a hot substrate. This phenomenon is characterised by the wetting and dewetting of the substrate, caused not by the rim dynamics, but induced by thermal effects. These thermal effects lead to the lamella evaporation, levitation and disintegration, generation of a vertical spray of fine droplets and consequently, drop breakup. A typical contact time of the drop before complete detachment is theoretically estimated. This estimation agrees very well with the experiments. It is shown that the Weber number, often used for describing splashing drops, is not a relevant parameter for thermal atomisation. Finally, a regime map is plotted, using a combination of the dimensionless contact time and the dimensionless heat flux at the substrate.

Thermal atomisation of a liquid drop after impact onto a hot substrate