Study of water droplet impinging on surface

Abstract

This report presents an investigation on measuring the maximum spreading diameter of fluid droplets after impinging onto dry substrates through the use of high-speed imaging techniques (a “Phantom V711” digital high-speed camera designed by Vision Research). Dynamics of drop impacts of fluid on dry surfaces have been investigated for over a hundred years due to its applications in the industrial area such as fuel injection, spray painting, ink-jet printing and spray cooling. Since the dynamical process occurs over a very short period of time, which is too short to be observed with the naked eye, and it requires high-resolution images for detailed observation. A digital high-speed camera, which is able to capture up to one million frames per second, is commonly used to record the entire process of droplet impact and to measure the fluid dynamic quantities such as the spreading diameter, the retracting speed and the rebounding height by analyzing its captured images. In this project, three influencing parameters are considered in the experiment: drop diameter, falling height and fluid viscosity. Images captured by the digital high-speed camera are collected, processed and analyzed. In addition, reviews on previous studies of the dynamic behaviors of drop impact of fluid and the related influencing factors are presented in separate sections to provide a systematic and clear research direction to the follow-up students.