Premixed flame extinction by inert particles in normal- and micro-gravity

• Published in: Combustion and flame Vol. 129; no. 1-2; pp. 179 - 191
• Main Authors: ANDAC, M. G, EGOLFOPOULOS, F. N, CAMPBELL, C. S
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Science 01.04.2002
• Subjects: Applied sciences; Combustion of gaseous fuels; Combustion. Flame; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Theoretical studies. Data and constants. Metering; Methane; Extinction; Premixed flame; Numerical simulation; Experimental study; Microgravity; Inert particle
• ISSN: 0010-2180; 1556-2921
• DOI: 10.1016/S0010-2180(02)00337-1

The extinction response of strained, atmospheric, premixed methane /air flames was studied experimentally and numerically in the presence of chemically inert particles. The experiments were conducted in normal- and micro-gravity using the opposed-jet configuration and by seeding the particles from the bottom burner. The numerical simulations were conducted by solving the conservation equations of mass, momentum, energy, and species with detailed descriptions of chemical kinetics, molecular transport, and thermal radiation for both phases, along the stagnation streamline of the counter-flow. The experimental data were compared with numerical simulations and insight was provided into the effects of equivalence ratio, strain rate, heat loss, particle size and type, gravity, and flame configuration. It has previously been shown experimentally and numerically that for low strain rates larger particles can cool the flames more efficiently compared to smaller particles. Numerical simulations have further shown that this trend is reversed at high strain rates. This prediction was experimentally confirmed in the present study, which also revealed that the crossover point depends not only on the particle size but also on the equivalence ratio of the gas-phase. (Author)