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AE Presents: Prof. Francesco Carbone, Yale University

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"Unveiling the Gas-to-Particles Transition in Flames: Resolving a Centuries-old Challenge"

Francesco Carbone

Department of Mechanical Engineering and Materials Science
Yale University

Montgomery Knight Room 317, 11 a.m.

Abstract

Flame-based technologies have ancient origins but still dominate the vast majority of energy conversion applications. They involve the formation of particles that are either pollutant byproducts of the process, primarily in the form of a carbonaceous material, i.e. soot, or, in some cases, engineered materials produced commercially (e.g., carbon black). Unveiling the fundamental mechanisms causing the gaseous reactants/intermediates in a flame to transition to particles is crucial from a fundamental perspective, but has also a practical impact, since the ability to control such a transition may yield substantial improvements in the flame processes. Such improvements would benefit the environment, climate and human health through emission abatement. Additionally, the fundamental knowledge gained could provide improved routes for large scale manufacturing of advanced materials.

The unresolved challenge of unveiling the gas-to-particle transition mechanisms in flames resides in the intrinsic difficulty to interrogate experimentally the growth chemistry of the gas phase and the physics of the aerosol in the nanometric dimensional scale of relevance, while minimizing the perturbation of the flame. I will present an overview of the results obtained with some innovative approaches in controlled sampling of both gas and particle phases and parametric variation of flame conditions (e.g., temperature). One approach provided an extensive experimental database of the gas phase structure of flames at pressures up to 25 bar, including the concentration profiles of polycyclic aromatic hydrocarbons, whose chemistry is fundamental to soot formation mechanisms. Perhaps remarkably, another approach has allowed for a virtually artifact-free measurement of the size distribution function of nascent soot particles in the dimensional range below 10 nm (i.e., at the molecule-to-particle transition, which I seek to help define). These novel experimental results highlighted pitfalls in the existing literature and areas of improvement in the understanding soot nucleation.

About the speaker

Francesco Carbone is an Associate Research Scientist in the Department of Mechanical Engineering and Materials Science at Yale University. His research focuses on multiphase reactive flows for energy applications and encompasses reaction kinetics, transport phenomena and aerosol dynamics. He authored over fifteen articles on peer-reviewed journals and contributed to the understanding of the fundamental mechanisms leading to pollutant nanoparticle emissions from combustion applications. He graduated with a PhD in Chemical Engineering from the University of Naples Federico II (Italy) and was subsequently appointed for postgraduate research positions in the Combustion Research Institute at the National Research Council (Italy, 2009-2010), in the Department of Mechanical Engineering at Yale University (2010-2012), and in the Department of Aerospace and Mechanical Engineering at the University of Southern California (2012-2014.

Status

  • Workflow Status:Published
  • Created By:Margaret Ojala
  • Created:02/02/2017
  • Modified By:Fletcher Moore
  • Modified:04/13/2017