Impact freezing of water droplet on an inclined hydrophobic surface

• Main Author: Neo, Min Yee
• Other Authors: Charles Yang Chun
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Aeronautical engineering
• Online Access: https://hdl.handle.net/10356/167577
• Institution: Nanyang Technological University

The impact behaviours of freezing water droplets are experimentally studied in this project in relation to the effects of hydrophobic surface inclination. Surface inclination angle, drop release height, and cooling temperature are three variables that were varied to a set of predetermined values during the experiment. To get exact adjustments for reliable readings and analysis, an experimental setup with a goniometer and retort stand was used. In the experimental method, a single drop of water was discharged at varying heights to hit a hydrophobic substrate that is positioned at various angles. In order to capture the impact process, a high-speed camera was utilized in conjunction with a lighting system positioned in the background. The open-source ImageJ software was then used to quantitatively analyse and research the photographs. The outcomes of the experiments were then examined and analysed to show how water droplets behave under the influence of various conditions. In this study, intriguing patterns have emerged from the introduction of water droplets onto an inclined surface. Droplet spreading time decreases as impact velocity increases. Droplet spreading time decreases as temperature decreases due to the different nucleation formation and impact freezing mechanism. The wettinging size of the droplet increase as impact velocity increase, while horizontal the wetting size spread more horizontally, vertical wetting size spread more vertically at different substrate angle due to the introduction of gravity at a steeper angle. The study also examined rivulet formation and proposed mechanisms that affect the length of the rivulet.