Spring 2000

ME/IE 8773-8774

COMPUTATIONAL AND EXPERIMENTAL STUDY OF AXISYMMETRIC LAMINAR DIFFUSION FLAMES

by

Mitchell D. Smooke
Chairman and Strathcona Professor
Department of Mechanical Engineering
Yale University
New Haven, CT 06520

Wednesday, April 19, 2000
3:35 - 4:25 p.m.
Room 108 ME
Broadcast on UNITE Channel A
Coffee will be available in 152 ME following the seminar

Recent advances in the development of computational algorithms, reaction kinetics, and high performance workstations have enabled the combustion scientist to investigate chemically reacting systems that were computationally infeasible only a few years ago. In particular, the coupling of adaptive numerical methods with large memory machines has produced an extremely powerful tool with which to probe flame structure. The difficulties in solving high heat release combustion problems, such as flames, center on 1) the large number of equations that must be solved for the elementary chemical species, 2) the exponential nonlinearities that occur in the governing partial differential equations, and 3) the disparate length scales that must be resolved in the computed solution. In this talk we investigate both numerically and experimentally one such reacting system--the axisymmetric laminar diffusion flame. Such flames are important in the interaction of heat and mass transfer with chemical reactions in gas turbines and commercial burners. The ability to predict the coupled effects of complex transport phenomena with detailed chemical kinetics in these flames is critical in the modeling of turbulent reacting flows, in improving engine efficiency and in understanding the processes by which pollutants are formed. In our study we consider an unconfined configuration in which a cylindrical fuel stream is surrounded by a coflowing oxidizer jet. Computationally, we solve the governing conservation equations of mass, momentum, species balance and energy with detailed transport and finite rate chemistry submodels. A discrete solution is obtained on a two-dimensional grid by employing Newton's method with adaptive mesh refinement. Unlike some models in which diffusion in the axial direction is neglected, we consider the fully elliptic problem. Experimentally, we apply spontaneous Raman spectroscopy and laser induced fluorescence to generate profiles of the temperature, the major and some minor species of the flame.

Dr. Mitchell D. Smooke is the Chairman and the Strathcona Professor of Mechanical Engineering at Yale University. He holds a joint appointment in the Department of Applied Physics. Dr. Smooke is also a member of Yale's Research Center for Scientific Computation. He received his Ph.D. in Applied Mathematics from Harvard University in 1978 and his M.B.A. in Management and Finance from the University of California at Berkeley in 1983. Before coming to Yale, he served as a Staff Scientist at Sandia National Laboratory in Livermore, California. His primary research interests lie in the areas of computational combustion, chemical vapor deposition and the numerical solution of ordinary and partial differential equations. Dr. Smooke has published numerous papers on the computational structure of flames and has served on various technical boards, including the ARO panel on nitramine propellants, the NSF Review Committee for Presidential Young Investigators, the SIAM Organizing Committee for the biannual meetings in Computational Combustion and the Program Committee of the International Combustion Symposium. His current research include:

computational studies of NOx and soot formation in flames,
the modeling of multidimensional premixed and nonpremixed flames on shared and distributed memory parallel supercomputers,
flamelet models for turbulent reacting flows, and
microgravity combustion.
His industrial ties include projects with United Technologies Research Center, Cummins Engine, General Electric and General Motors Research Laboratories.

Faculty Host: Prof. Michael R. Zachariah