Surface Functionalization for Studies of Icing of Impacting Droplet

• Grant number: 24/18585-0
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: March 01, 2025
• End date: May 24, 2025
• Field of knowledge: Engineering - Mechanical Engineering - Thermal Engineering
• Principal Investigator: Arthur Vieira da Silva Oliveira
• Grantee: Murillo Augusto Correa Masculi
• Supervisor: Daniel Orejon Mantecon
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: University of Edinburgh, Scotland
• Associated to the scholarship: 23/09775-7 - Characterization of the freezing process of droplets on cold surfaces using optical techniques., BP.IC

Abstract

The impact of droplets on solids is a phenomenon widely present in various areas of engineering, showing different behaviors depending on the type of surface and the thermal conditions involved. In aeronautics, for example, water droplets can impinge an aircraft during ight, especially in rainy conditions, representing a signicant risk. This can compromise visibility in the cabin and, in more critical situations, lead to droplets freezing, resulting in the aerodynamic instabilities and potential failure of essential equipment such as the Pitot Tube, aps and turbine blades. In order to better understand the behavior of droplet freezing on cooled surfaces, an Undergraduate Research funded by FAPESP started in 2023 at EESC/USP (São Carlos). So far, initial droplet freezing tests have been carried out using the Shadowgraph optical technique on aluminum surfaces. However, it is essential to expand the research to assess the impact of droplets on different surfaces, both at room temperature and under freezing conditions, as occurs in the aeronautical context. The study of the impact of droplets on surfaces made of different materials, structures and functionalization, aims to enhance our fundamental understanding of the phenomena and to propose solutions to mitigate the problems mentioned above. In this internship abroad project for a BEPE (Bolsa Estágio de Pesquisa no Exterior) scholarship, surfaces of materials such as aluminum and glass, with hydrophobic, superhydrophobic and hydrophilic characteristics, will be used to analyze the behavior of droplets during impact at different temperatures including room temperature and below 0 °C. In addition, periodic wettability characterization will be carried out based on the contact angle adopted by the droplet on a solid surface, which is considered as a metric determining the interactions between liquids and solid surfaces. More specically, the current project systematically tackles the effect of impact velocity, ambient and surface temperatures, and surface wettability including hydrophilic glass and aluminum, smooth funtionalized hydrophobic and structured hydrophobic or superhydrophobic surfaces. The proposed project is in line with the research interests of the Host Dr. Daniel Orejon Mantecon Senior Lecturer in Chemical Engineering at the University of Edinburgh (UoE). More in particular, the applicant will benet from the experimental capabilities at the Hosts laboratory including environmental chambers, shadowgraphy, microgoniometry, etc. as well as from mastering the different surface funtionalization techniques developed and adopted at the UoE. While the Host will benet from deepening into a new topic on droplet impact and freezing very much related to his interests on droplet manipulation and control as well as the effect of surrounding environment onwetting and phase-change. The surfaces prepared in Edinburgh will later be applied in Brazil to continue the droplet freezing tests, which are the main objective of the Undergraduate Research.