Showing papers by "Vasudevan Raghavan published in 2010"
TL;DR: In this article, a numerical study of laminar boundary layer type diffusion flames established over a liquid fuel pool, under the influence of forced air flow parallel to the pool surface, has been carried out.
22 citations
TL;DR: In this article, a numerical study of laminar diffusion flames established over a condensed fuel surface, inclined at several angular orientations in the range of −90°⩽θ−+90° with respect to the vertical axis, under atmospheric pressure and normal gravity environment, is presented.
Abstract: A numerical study of laminar diffusion flames established over a condensed fuel surface, inclined at several angular orientations in the range of –90°⩽θ⩽+90° with respect to the vertical axis, under atmospheric pressure and normal gravity environment, is presented. Methanol is employed as the fuel. A numerical model, which solves transient gas-phase, two-dimensional governing conservation equations, with a single-step global reaction for methanol–air oxidation and an optically thin radiation sub-model, has been employed in the present investigation. Numerical results have been validated against the experimental data from the present study. Thereafter, the model is used to investigate the influence of angular orientation of fuel surface on its quasi-steady burning characteristics. Results in terms of fuel mass burning rate, flame stand-off distances, temperature field, velocity profiles and oxygen contours have been presented and discussed in detail. It is observed that orientation angles in the range of –...
20 citations
TL;DR: In this paper, a numerical model, which employs different chemical kinetics sub-models, including a skeletal mechanism with 43 reaction steps and 18 species and four global reaction mechanisms (two 2-steps and two 4-steps mechanisms), and an optically thin radiation sub-model, has been employed in the simulations.
Abstract: Laminar co-flow methane–oxygen flames issuing into the unconfined atmosphere have been studied. A numerical model, which employs different chemical kinetics sub-models, including a skeletal mechanism with 43 reaction steps and 18 species and four global reaction mechanisms (two 2-steps and two 4-steps mechanisms), and an optically thin radiation sub-model, has been employed in the simulations. Numerical model has been validated against the experimental results available in literature. The numerical predictions from the global kinetic mechanisms have been compared with the 43-steps mechanism predictions. At all oxygen flow rates, the predictions of the distributions of temperature, mass fractions of CH4, O2 and CO2 by the 2-steps mechanisms are closer to 43-steps mechanism. The overall distribution of H2O predicted by 2-steps mechanisms is close to that of 43-steps except for the maximum value. Especially at higher oxygen flow rates, the modified 2-steps mechanism predicts these quantities much closer to t...
17 citations
TL;DR: In this paper, the extinction characteristics of non-premixed flames were used to estimate the single-step kinetics parameters for ethanol oxidation in air. And the extinction velocities for different sphere sizes were employed in a numerical model and extinction characteristics for opposed-flow ethanol-air diffusion flames have been predicted and validated against the available experimental results.
Abstract: In this study, based on the extinction characteristics of nonpremixed flames, global single-step kinetics parameters are estimated for ethanol oxidation in air. Using a quasi-steady heterogeneous experimental setup, the air velocity at which an envelope flame surrounding the sphere transits to a wake flame that burns in the rear region of the sphere, termed as the transition or the extinction velocity, were obtained in a previous study. These extinction velocities for different sphere sizes are employed to estimate the single-step kinetics parameters. The estimated global single-step kinetics has been employed in a numerical model and extinction characteristics of opposed-flow ethanol-air diffusion flames have been predicted and validated against the available experimental results in literature.
17 citations
TL;DR: In this paper, a numerical model was used to investigate gas-phase entropy generation during transient methanol droplet combustion in a low-pressure, zero-gravity, air environment.
15 citations