Woodruff School of Mechanical Engineering
Heat and Mass Transfer Resulting in Eruptive Jetting from Stems and Leaves during Distillation Stage of Forest Fire
Prof. Alexander Yarin
University of Illinois at Chicago
Tuesday, February 16, 2021 at 1:00:00 PM
Forest fires are common large-scale environmental disasters with annual death toll and damages on the scale of tens of billions of dollars. We explore experimentally and theoretically a novel mechanism responsible for fuel and water vapor supply into flame in the form of volatiles-water vapor jets erupting from plants engulfed in fire. This mechanism is significantly accelerated in comparison with the ordinary-implied evaporation/sublimation and diffusion characteristic of the diffusion flames. The eruptive jets accelerate fuel supply into the flame zone and plant drying before burning, which facilitates forest fire. They also ballast the flame zone with water vapor, i.e. provide a counter-acting flame-quenching path. The eruptive jets are observed in the experiments with horizontal stems and leaves subjected to the engulfing flame, and the results are explained and predicted theoretically. Also, as a model system, a horizontal syringe needle filled with liquids and subjected to the surrounding flame is used as a stem substitute to separate the effect of water vapor from that of combustible volatiles modeled by ethanol. The predicted eruption velocity of ~10 m/s is in good agreement with the experimental data.
MSc-1977 (in Applied Physics), PhD (in Physics and Mathematics)-1980, DSc (Habilitation, (in Physics and Mathematics)-1989. Affiliations: The Institute for Problems in Mechanics of the Academy of Sciences of the USSR, Moscow (1977-1990); Professor at The Technion-Israel Institute of Technology (1990-2006; Eduard Pestel Chair Professor in Mechanical Engineering at The Technion in 1999-2006); Distinguished Professor at The University of Illinois at Chicago, USA (2006-present); Fellow of the American Physical Society. Prof. Yarin is the author of 5 books, 12 book chapters, 400 research papers, and 12 patents. Prof. Yarin was the Fellow of the Rashi Foundation, The Israel Academy of Sciences and Humanities, and was awarded The Gutwirth Award, The Hershel Rich Prize, and The Prize for Technological Development for Defense against Terror of the American-Technion Society. He is one of the three co-Editors of ‘Springer Handbook of Experimental Fluid Mechanics’, 2007, the Associate Editor of the journal “Experiments in Fluids”, and the member of the Editorial Advisory Board of ‘Physics of Fluids’, the Bulletin of the Polish Academy of Sciences, and ‘Archives of Mechanics’.