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Dynamical System Analysis of Ignition in Reactive Systems By Prof. Mauro Valorani (Sapienza, University of Rome, Italy)

  • Speaker: ​Dr. Mauro Valorani
  • Authors: M. Valorani, S. Paolucci, E. MartelliM
  • Class schedule: Tuesday, Sept. 25th, 2012 from 04:00 pm to 05:00 pm
  • Location: Building 9, Lecture Hall 1, Room 2322
  • Refreshments: Available @ 3:45 pm
  • Seminar material available at: link


Abstract

Ignition of hydrocarbon fuels is controlled by branched-chain reactions and its complexities increase with the length/size of the fuel molecule.

Recent analyses in the Literature pointed out the significance of eigenvalues with a positive real part in ignition and otherlimit phenomena.

Willing to explore ignition with the simplest possible model, we consider a planar (2D) model for spatially homogeneous systems: an isothermal branched-chain explosion model proposed by Williams.  We analyzed Williams' model by means of thelocal (tangential and normal) stretching rate concept introduced in the geometrical analysis of dynamical systems. We also introduce a normalized index measuring the relative contribution of each mode to the tangential stretching rate (TSR). This index can be further combined with the standard Participation Index of reactions to a mode as defined in CSP to obtain a direct link between reactions and the TSR.  We will present the outcome of this novel type of analysis with reference to the ignition of a number of hydrocarbon fuels.


Biography

Dr. Mauro Valorani is Associate Professor of Aerospace Propulsion at the Department of Mechanics and Aerospace Engineering, Sapienza University, Rome, since 1998. In 2010, he obtained the habilitation to Full Professor from Polytechnic     University of Torino, Italy.  He graduated in Mechanical Engineering at Trieste, Italy in 1985. He took the VKI Diploma in Environmental and Applied Fluid Dynamics in 1984, from the Von Karman Institute for Fluid Dynamics, Bruxelles, and the Ph.D. Degree in Applied Mechanics from Sapienza U..

Prof. Valorani research work is mostly related to modeling and computational techniques in Reacting Flows (Combustion, Aero-thermo-chemistry); model reduction, analysis, and solution of large chemical kinetic mechanisms in view of CFD   applications; development of stiff solvers for dissipative systems. He recently started working on UQ problems in Reacting Flow.

He developed a long-standing scientific collaboration with CRF/SANDIA, and several other collaborations with a number of European and US Universities.

He is member of the Scientific Committee of the International Workshop in Model Reduction in Reacting Flow.  

He has chaired or co-chaired a number of international workshops or mini-symposia. He gave seminars and invited lectures at Stanford U., Virginia Tech U., CNES Evry, INRIA Rocquencourt, INRIA Rennes, CRF/Sandia, Patras U., Michigan U.,KAUST.

He is the Scientific and Didactical Coordinator of a Master Course in Space Transportation Systems, Sapienza - University of Rome (http://w3.uniroma1.it/stsmastercourse).

He teaches undergraduate and graduate courses in Aerospace Propulsion (Gas Turbine Engines, Combustion, ...) at the Faculty of Civil and Industrial Engineering, Sapienza - University of Rome.

He acted as consulant for the European Space Agency (ESA), the Italian Space Agency (ASI); AVIO Group, Rivalta, Italy; ENEA Casaccia, Italy; Italian Ship Naval Basin (INSEAN), Italy; CIRA, Italy.

He is Senior Member of the American Institute Aerospace and Astronautics, Member of the Combustion Institute (Italian Section), Member of Von Karman Institute Alumni Association.

He is author and co-author of more than 70 papers on International Archival Journals and International Conference Proceedings.  His papers have collected more than 500 citations (http://w3.uniroma1.it/mauro.valorani/Publication.html).



His five most cited papers (Source: Google Scholar) are:

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M.Valorani, D.A.Goussis, Explicit time-scale splitting algorithm for stiff problems: auto-ignition of gaseous mixtures behind a steady shock, Journal of Computational Physics 169 (1), 44-79, 58 citations, 2001.

M.Valorani, H.N.Najm, D.A.Goussis, CSP analysis of a transient flame-vortex interaction: time scales and manifolds, Combustion and Flame 134 (1-2), 35-53, 51 citations, 2003

M.Valorani, D.A.Goussis, F.Creta, H.N.Najm, Higher order corrections in the approximation of low-dimensional manifolds and the construction of simplified problems with the CSP method, Journal of Computational Physics 209 (2), 754-786, 37 citations, 2005

D.A.Goussis, M.Valorani, An efficient iterative algorithm for the approximation of the fast and slow dynamics of stiff systems, Journal of Computational Physics 214 (1), 316-346, 33 citations, 2006.

A noteworthy papers is:

M.Valorani, S.Paolucci, The G-Scheme: A framework for multi-scale adaptive model reduction, Journal of Computational Physics 228 (13), 4665-4701, 13 citations, 2009.