Energy balance during a droplet impact on a heated wall

• Grant number: 24/10845-2
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2024
• End date: July 31, 2026
• Field of knowledge: Engineering - Mechanical Engineering - Transport Phenomena
• Principal Investigator: Arthur Vieira da Silva Oliveira
• Grantee: Marina Holanda Feitosa
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 21/01897-0 - Experimental study of droplets impact onto heated walls using combined optical techniques: single droplets, multiple droplets and sprays, AP.JP

Abstract

The use of combined optical techniques is an important step forward to better characterize complex thermal-hydraulic phenomena. For example, for droplet impact studies, using simultaneously Shadowgraph (SDG), Laser-Induced Fluorescence (LIF), Infrared Thermography (IRT) and Total Internal Reflection (TIR) allows measuring, at the same time, the droplet shape (SDG), velocity (SDG) and temperature (LIF), as well as the wall temperature (IRT) and the wall-fluid contact area (TIR). Nevertheless, their implementation is a difficult task because not only images must be synchronized but also these independent results must be processed and interpreted together to analyze comprehensively the involved phenomena. The main objective of the present master project is implement combined optical techniques, focusing on the development of the IRT and LIF techniques for the wall and fluid transient temperature maps, and evaluate the parameters uncertainties and sensitivities in single droplet studies. The master student will perform experiments with both sessile and impacting water droplets on a sapphire substrate with ITO or FTO coating.The master student will perform experiments for all the heat transfer regimes with sessile droplets, including single-phase evaporation (no bubble formation) and nucleate boiling (with bubble formation) where the solid-liquid contact is established, and compare the energy dissipated by the droplet from the wall and the sensible heat with the droplet heating.