Burning Velocity of Turbulent Methane/Air Premixed Flames in Subatmospheric Environments

Abstract

The aim of our work was to study turbulent premixed flames in subatmospheric conditions. For this purpose, turbulent premixed flames of lean methane/air mixtures were stabilized in a nozzle-type Bunsen burner and analyzed using Schlieren visualization and image processing to calculate turbulent burning velocities by the mean-angle method. Moreover, hot-wire anemometer measurements were performed to characterize the turbulent aspects of the flow. The environmental conditions were 0.85 atm, 0.98 atm, and 295 ± 2 K. The turbulence–flame interaction was analyzed based on the geometric parameters combined with laminar flame properties (which were experimentally and numerically determined), integral length scale, and Kolmogorov length scale. Our results show that the effects of subatmospheric pressure on turbulent burning velocity are significant. The ratio between turbulent and laminar burning velocities increases with turbulence intensity, but this effect tends to decrease as the atmospheric pressure is reduced. We propose a general empirical correlation as a function between S T / S L and u ′/ S L based on the experimental results obtained in this study and the equivalence ratio and pressure we established.

Experimental study of the correlation for turbulent burning velocity at subatmospheric pressure

“…Similar studies in the literature [22] present the turbulent burning correlation, this correlation presented a relation between pressure and turbulent intensity. In the present work, the turbulent burning velocity relation is presented by turbulence intensity dependence.…”

Dynamics of Thermoacoustic Oscillations in Swirl Stabilized Combustor without and with Porous Inert Media

“…e velocity results in Figure 11 exiting the central region of the PIM are also significantly higher than the turbulent flame speeds [50], making it unlikely for a flame to stabilize in that core flow region within the PIM. Turbulent flame speed between 0.4 and 2 m/s was found by Vargas et al [50] for equivalence ratios between 0.8 and 1 for atmospheric methane combustion.…”

“…e velocity results in Figure 11 exiting the central region of the PIM are also significantly higher than the turbulent flame speeds [50], making it unlikely for a flame to stabilize in that core flow region within the PIM. Turbulent flame speed between 0.4 and 2 m/s was found by Vargas et al [50] for equivalence ratios between 0.8 and 1 for atmospheric methane combustion. As the majority of the burning is interacting with the recirculation zones at the exit of PIM, the pressure gradient induced by PIM and the physical distance to the baseplate significantly reduce burning interaction with the flow entering the combustor.…”

“…is is explained in the next paragraph by the mean velocity and its inverse relation to the convective time delay. e convective time delay is defined as the amount of time it takes the fuel to convect from the injection site to the flame front, which has been previously shown to be a critical parameter in the system stability [4,50].…”

Hacia una estructura de investigación y educación para la prevención de accidentes por incendios y explosiones en Colombianción de accidentes por incendios y explosiones en Colombia

“…Amell et al, 2007;A. M. García & Amell, 2018) Combustión a presiones inferiores a la atmosférica (Cano et al, 2019;Vargas et al, 2020) Combustión de hidrógeno (Burbano et al, 2008;Cardona-Vargas et al, 2020;Juan P. Gómez Montoya et al, 2018) Combustión de gas de síntesis y biogás García, Yepes, et al, 2019;Cacua et al, 2011aCacua et al, , 2011bCano et al, 2019 Suarez-Paba et al, 2019 terremotos, oleaje extremo, relámpagos y truenos, accidentes volcánicos, vientos y desplazamientos de tierra (Alvarado-Franco et al, 2017;Bernal et al, 2017;Kabir et al, 2019;Olivar et al, 2020;Rangel-Buitrago et al, 2018;Salgado-Gálvez et al, 2014;Tovar et Baalisampang, T., Abbassi, R., Garaniya, V., Khan, F., & Dadashzadeh, M. (2018).…”