Experimental Study of Impact Force of a Low-Speed Droplet Colliding on the Solid Surface at Different Impact Angles

Erosion problems due to droplet impacts are widely encountered in many fields. This may result in deterioration or even failure of the elements, and should be taken into consideration in the design of machines. The impact force is thought of as an essential factor in material erosion. In this paper, a highly sensitive piezoelectric force transducer was employed to record the impact force of the low-speed droplet colliding on an aluminum plate at different impact angles, in combination with a high-speed camera used to capture the impact process of the droplet. The results showed that the experimental setup can measure the impact force evolution precisely and reliably. The peak of the normal impact force increases with the normal velocity quadratically, while the impulse increases with the normal velocity linearly. In addition, a smaller impact angle would lead to longer time duration of the impact force. The high-speed images show that the initial impact patterns of the droplet have similar behavior in the initial impact process, with regardless of vertical or oblique impacts.