The disintegration limits depend on the properties of the liquids but are also strongly related with surface topography and wettability. In partial wetting systems, different disintegration mechanisms are identified (prompt splash, finger break-up and receding break-up) which can be distributed in several regions, as depicted in the figure, representing the disintegrating limits for water droplets impacting onto targets made of different materials and with different surface topographies.
Liquid fuels behave differently since they completely wet the surface, as it happens with liquids with small surface tension. In this case the droplets are observed to disintegrate with crown formation. The surface tension of the studied fuels does not differ much, so the increase of the critical Weber number for the occurrence of disintegration is attributed to an increase of the kinematic viscosity. The use of liquid fuels with larger viscosity also alters the morphology of the crown and the secondary droplet characteristics, giving rise to less and larger secondary droplets.