Influence of Different Flow Rates and Disturbed Flow on Liquid Droplet Characteristics Using Particle Image Velocimetry and High-Speed Imaging

Abstract

Abstract. The erosion that results from droplet impact on a solid surface is significant for many parts of industrial machinery. Even though many modeling and experimental studies have been done on this subject, few have included quantitative research, particularly in regard to wind turbine blade erosion. Furthermore, most methods assume that there is no local turbulence or vortex shedding and that the striking droplets are perfectly spherical. This study focuses on examining droplet characteristics and movement in a controlled lab environment because the droplet erosion process could be influenced by multiple aspects, including the impact velocity, shape, and size of the droplets. For this, particle image velocimetry (PIV) techniques and high-speed imaging are employed. PIV is utilized in both disturbed and undisturbed flow regimes to quantify the size, velocity, and circularity of the falling droplets. Additional information on the droplets' travel path in the presence of turbulence can be obtained from high-speed camera images. A range of blunt needle gauge sizes 14 GA to 21 GA is used in the experiments to create distinct droplet sizes at different flow rates. It was observed that after each leading droplet, the blunt needles create a train of droplets of varying sizes. By employing PIV and high-speed imaging to investigate a larger range of needle sizes and flow rates, this study builds on the earlier research. It offers a more thorough understanding of droplet behavior and explains their properties and mobility in a laboratory setting under both disturbed and undisturbed flow circumstances. This is an important finding that will directly affect the amount of erosion and should be taken into account in any future modeling projects.