Comparison of experimental data of dissipated energy during a droplet impact on heated walls and spray cooling

• Grant number: 23/14469-2
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: December 20, 2023
• End date: March 11, 2024
• Field of knowledge: Engineering - Mechanical Engineering - Transport Phenomena
• Principal Investigator: Arthur Vieira da Silva Oliveira
• Grantee: Carlos Eduardo Brasil de Mendonça Rocha
• Supervisor: Yutaku Kita
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Institution abroad: King's College London, England
• Associated to the scholarship: 23/03243-3 - Spray cooling: transient thermal modeling with the Monte Carlo method, BP.IC

Abstract

Droplet impact on surfaces is a process found in various engineering applications, such as metallurgy, nuclear reactors, internal combustion engines, propulsion turbines, cooling of electronic components, among others. To better characterize the hydrodynamic and thermal processes during the impact of one or more droplets on a heated surface, a research project was initiated in 2022 with the support of FAPESP Young Researcher at EESC/USP (São Carlos), in which several optical techniques will be used to perform the necessary measurements. To date, some tests involving the impact of a single droplet on the wall have been conducted, but it is necessary to advance the work to examine the impact of multiple droplets during the cooling of a metal plate, i.e., spray cooling. In this Undergraduate Research, we will perform three-dimensional and transient numerical heat conduction simulations representing spray cooling of a metal plate. As boundary conditions for these simulations, we will use mechanistic hydrodynamic and thermal models of droplet impact on a heated wall available in the literature. However, there are plenty of discrepancies between the results in the literature and the source of these discrepancies is not easily determined because of the different methods of droplet generation, different forms of analyzes of the experimental data, and other experimental approaches. For this reason, it is important to have not only available data in the literature to compare, but also different raw experimental data to process and find the reasons that may explain the large difference between the results from different papers. Therefore, the current Research Internships Abroad (BEPE) project seeks to compile and compare experimental data on energy dissipation for isolated droplets: those obtained in Brazil during prior projects, those collected by Dr. Kita's, lecturer at King's College London, and others published in the literature. Experimental data from spray cooling experiments conducted by Dr. Kita will also be available for analysis, enabling the acquisition of reliable results for comparison with the spray cooling numerical simulations that are the objective of the Undergraduate Research in Brazil. (AU)