Comparative Study of Droplet Impact onto Sloped Surface versus a Droplet Impact onto a Surface with a Crossflow

Abstract

Droplet impact is a common phenomenon that occurs frequently in several applications such as fuel injection in internal combustion engines, processes involving spray paints and cooling of electronic equipment. In the study of droplet impingement, the influencing parameters are the liquid, along with its physical properties, the impact surface, the surrounding environment and others conditions. The major goal of the present work is a comparison that involves an experimental study of the phenomena occurring during the impact of liquid droplets onto a dry surface with a cross flowing air and droplets impacting onto a sloped surface. Due to the crossflow, the droplet does not have the same direction as the gravitational acceleration and suffers a certain deformation that seems to vary the impact condition. For the sloped surface, the droplet is spherical throughout the trajectory and both the gravitational acceleration and movement of the droplet have the same direction. Four fluids were used: 100% Jet-Fuel, 75% Jet-Fuel-25% HVO, 50% Jet-Fuel-50%. HVO and H2O (pure water) as a reference. In order to maintain the coherence of the results between the two experimental works, the impact velocity and incident angle were kept approximately the same.