PhD Seminar Series: “Time resolved reaction and diffusion limited carbon oxidation dynamics at the micro-scale”and “Particle-laden flows, from incompressible turbulence to supersonic jets”.

We will continue with our Seminar Series on Tue, 16 dec 2021.

On site: Aula de Grados Leganés

Online: https://media.uc3m.es/live/event/61b7081b8f42083ce68b459c

For the upcoming event of the Aerospace PhD Seminar Series we will have the pleasure to host Dr. Francesco Panerai and Dr. Laura Villafañe from University of Illinois Urbana-Champaign.

The event will take place in Salón de Grado on Thursday December 16th at 13.00, and will be broadcasted in streaming.

“Time resolved reaction and diffusion limited carbon oxidation dynamics at the micro-scale”

Prof. Francesco Panerai.

Prof. Francesco Panerai is an Assistant Professor in Aerospace Engineering at the University of Illinois at Urbana-Champaign. Prior to Illinois, he was a research scientist at NASA Ames Research Center in California. His research covers advanced materials for extreme environments, transport in porous media, and hypersonic aerothermodynamics. Francesco received his PhD and Research Master in Aeronautics and Aerospace from von Karman Institute for Fluid Dynamics (Belgium) and a M.Sc. and a B.Sc. in Mechanical Engineering from the University of Perugia (Italy). He is recipient of the 2019 Air Force Young Investigator Award.

Abstract: High-temperature porous media constitute critical elements of hypersonic flight systems. To be safe and effective throughout the extreme conditions of re-entry, their design must anticipate and be robust to changes in the aerodynamic shape and surface roughness due to ablation. This talk will focus on lightweight carbon fiber systems, a prominent ablator class developed at NASA for planetary entry systems. To resolve ablation phenomena, laboratory experiments were conducted with the goal of simulating aerothermal loads encountered in real flight conditions. We will discuss how X-ray tomography imaging at high resolution enables understanding the micro-structure and quantify the response of porous architectures used in charring ablators. The core of the talk will focus on new experiments performed at the Swiss Light Source (SLS) synchrotron facility, where carbon fiber oxidation at high-temperature was resolved for the first time in 4D, using real-time X-ray micro-tomography. From the high spatial and temporal resolution scans we were able resolve oxidation processes at different conditions found in high-speed flight, from the reaction-limited to the diffusion-limited regime. These data constitute the basis for predictive modeling tools for carbon ablation and high speed vehicle design.

“Particle-laden flows, from incompressible turbulence to supersonic jets”

Prof. Laura Villafañe.

Prof. Laura Villafañe is an Assistant Professor in the Department of Aerospace Engineering at the University of Illinois at Urbana-Champaign. Her research focuses on turbulence, multiphase flows, and on the development of experimental diagnostics and data analysis tools to study complex fluid mechanic problems. Laura received her B.Sc./M.Sc. degrees in Aerospace Engineering from the Polytechnic University of Madrid, and a Research Master in Fluid Mechanics and a Ph.D. from the von Karman Institute for Fluid Dynamics, Belgium. Prior to joining UIUC she was Postdoctoral Fellow and Research Associate at the Center for Turbulence Research at Stanford University. Laura is the recipient of two NASA Early-Stage-Innovation awards in 2019 and 2020.

Abstract: Small inertial particles dispersed on a moving fluid often distribute non-homogeneously and may alter the dynamics of the carrier flow. Our ability to predict the dispersion of pollutants, optimize a wide range of industrial processes and ensure safe landings in sandy environments relies on advances on particle-laden flows across a range of flow and particle loading regimes. In this talk we will discuss two distinct ongoing efforts. We will first present a complex high-speed multi-physics problem with implications to planetary exploration. The impingement of a supersonic plume onto a granular surface leads to a dense ejecta cloud and high-speed radial particle-laden jets.  The optically opaque particle-fluid mixture prevents quantitative measurements. We will focus on a novel millimeter wave interferometer capable of providing time-resolved measurements of path-integrated ejecta concentration. Results for different jet-expansion-ratios will be correlated to flow dynamics from flat-plate impingement experiments. The second part of the talk will cover a more fundamental particle-turbulence interaction study focused on particle preferential concentration. We will present a new method for cluster identification rooted on density-based clustering algorithms that outperforms Voronoi methods in terms of computational cost, while facilitating temporal tracking of clusters.

The seminars will begin at 13 CEST and will take place in the Auditorium Salon de Grados (Padre Soler) campus of Leganés.
No previous registration is required.

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