Comprehensive experimental study of droplet impact on heated sapphire substrates in the Leidenfrost and the transition boiling regimes.

• Grant number: 24/17883-7
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: February 01, 2025
• End date: January 19, 2026
• Field of knowledge: Engineering - Mechanical Engineering - Transport Phenomena
• Principal Investigator: Arthur Vieira da Silva Oliveira
• Grantee: Alvaro Felipe Campos Araya
• Supervisor: Michel Guy Alain Gradeck
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: Université de Lorraine (UL), France
• Associated to the scholarship: 23/15397-5 - Wall rewetting during single and multiple droplet impact on a heated surface: theoretical and experimental investigation, BP.DD

Abstract

Droplet impact has garnered significant interest in academia due to its numerous industrialapplications, such as steam turbines, falling film evaporators, internal combustion engines,and spray cooling. Despite the broad range of applications, the heat transfer processes betweendroplets and heated surfaces are not yet fully understood, largely due to the numerousvariables involved, such as fluid and surface properties. This research internship, in collaborationwith the Laboratoire Énergies et Mécanique Théorique et Appliquée at the Universityof Lorraine in Nancy, France, aims to characterize the thermal and hydrodynamic behaviorof single and multiple simultaneous droplet impacts on heated sapphire substrates, with a focuson the Leidenfrost and transition boiling regimes. The project will involve assembling anexperimental setup able to apply Infrared Thermography and Laser-Induced Fluorescenceto study the impact of a single droplet. Subsequently, the setup will be upgraded to applythe same techniques for a simultaneous multiple droplet impact. Furthermore, this study willgenerate an extensive experimental database to evaluate the effects of substrate temperatureand droplet impact velocity on heat transfer, extract key parameters such as temperaturefields of both the substrate and droplets, aiming to develop physical models to estimate criticalparameters like the heat transfer coefficient and Leidenfrost temperature. This internshipwill enable experiments under different and unique conditions, expanding the research scopeand complementing the experimental data currently available at the São Carlos School ofEngineering.