Effect of CO2 diluent on fuel versus oxidizer side of spherical diffusion flames in microgravity

A computational study of spherical diffusion flames in microgravity with gas radiation. Part II: Parametric studies of the diluent effects on flame extinction

“…The larger sensitivity of flame radius and temperature to oxidizer-side dilution is in contrast to an earlier experimental study [9,15] in which the flame radius and temperature behavior for some cases was found to be more sensitive to the fuel-side dilution. In the experiments, however, the comparison between fuelside and oxidizer-side dilution conditions was not conducted in a consistent manner throughout the entire experimental data set, such that it was difficult to draw a definite conclusion.…”

“…Various experimental studies have been conducted in the NASA 2.2-s drop tower facility. Atreya and coworkers [5][6][7][8][9] have conducted experimental measurements of flame radius and temperature evolution, considering the effects of diluent gases. Tse et al [10] also experimentally measured flame radius growth, which was used to validate various radiation models employed in their simulations.…”

“…Therefore, the objective of the present study is to systematically investigate fundamental aspects of radiative extinction for a wide range of mixture conditions by utilizing the one-dimensional computational model with detailed radiation models described in the previous paper (referred to as Part I). The models have been carefully validated against the temporally and spatially resolved flame radius and temperature measurements [9], such that comprehensive computational parametric studies can be performed with high fidelity for a long period of time. In particular, one of the key issues in the present study is the effect of various diluent gases, both in the fuel and oxidizer-side, on the flame growth and extinction behavior.…”

Extinction of premixed methane/air flames in microgravity by diluents: Effects of radiation and Lewis number

“…Such gases may be essential, for example, for extinguishing fires in confined environments such as spacecraft. The extinguishing mechanisms of these diluents have been studied experimentally and computationally for various flame configurations at terrestrial or microgravity conditions [1][2][3][4][5][6][7][8].…”

A Detailed Numerical Study of NOx Kinetics in Counterflow Methane Diffusion Flames: Effects of Fuel-Side versus Oxidizer-Side Dilution

“…To obtain a fundamental understanding of the effect of dilution position (i.e., through air or fuel stream) on flame characteristics, attention has also been paid to one-dimensional diffusion flames, which excludes the burner's complexity and flow field in multidimension flames. Using spherical diffusion flames, Chernovsky et al [19] experimentally investigated the impact of adding CO 2 on the oxidizer side versus the fuel side. eir results showed that CO 2 dilution affects the flame in these two dilution scenarios by different mechanisms.…”