Experimental and CFD simulation of interactions between water droplets with different surface features to understand water droplet erosion

Water droplet erosion (WDE) has received considerable attention in recent years. Different approaches have been proposed to understandWDE and find lasting solutions. Among them is understanding the interaction between the droplet impacts and the target surface, especially at the erosion initiation stage. For this reason, we studied the interactions between water droplets and different surface features to understand WDE. These surface features included flat smooth surfaces and grooved and porous samples. For the grooved samples, depths of 1.0 and 0.5 mm were studied and their WDE performance was evaluated. The 0.5 mm groove showed a longer incubation period than the flat reference sample. This work suggested that a thin water film is formed in the groove, which aids in dampening the impacts of subsequent water droplets. However, the maximum erosion rate is not affected by introducing these grooves. The WDE performance of the porous samples is better than that of the solid material. This is because the porous structure dissipates the impact energy of the water droplets. The simulation results were in agreement with the experimental observations in this work. Furthermore, the simulation showed that the water droplet impacting patterns on different surface features are attributed to the effect of radial and axial airflows.