Characterization of in-house perforated membranes for a droplet train generator

• Grant number: 22/14365-0
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: January 23, 2023
• End date: March 22, 2023
• Field of knowledge: Engineering - Mechanical Engineering - Transport Phenomena
• Principal Investigator: Arthur Vieira da Silva Oliveira
• Grantee: João Marcelo Maris da Silva Filho
• 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: 22/05287-5 - High-repeatability monodisperse droplet generator: project, development and validation, BP.IC

Abstract

Droplet generation is fundamental for studies involving fluid-wall interaction. Among others, there are two well-defined methods to generate droplets, which are drop-on-demand (DOD) and continuous-stream. DOD is characterized by a unique droplet detachment, and it is based on the balance forces acting on the fluid mass. In this Undergraduate Research we designed a DOD droplet generator mode, which is under construction and will be used for studies involving single- and multiple-droplet impact tests. Continuous-stream is characterized by a fluid jet that is broken into a train of droplets, and it is founded on the Plateau-Rayleigh instabilities. The continuous-stream has great importance since it can better represent real spray cooling applications. This research internship project has the objective to evaluate the performance of in-house, low-cost perforated membranes built by laser cutting and mounted in a commercial droplet train generator using high-speed imaging. The student will take in-house membranes fabricated in Brazil to be tested at a continuous-stream droplet generator available at LEMTA, Université of Lorraine, in Nancy, France. First, the original and in-house membranes will be compared, more precisely the droplet diameter and repeatability, as well as the breakup length. Then, several different types of in-house membranes (varying the hole diameter, number of holes and distance between holes) will be evaluated in both single and multiple drop train situations. These tests will bring an important know-how to the research group on the perforated membrane fabrication, which will contribute for the Young Investigator project to perform a large amount of experiments to validate the fluid dynamics and heat transfer models of multiple droplet impact, which is lacking in the literature today. Finally, the student will have early contact with a recognized French laboratory, which can provide him with high-level professional experience. (AU)