A study of the effects of diluents on near-limit H2–air flames in microgravity at normal and reduced pressures

Comprehensive H2/O2 kinetic model for high‐pressure combustion

“…model and that of Li et al [12] agree within 20%, or reported experimental error bars, except for equivalence ratios lower than 0.4 (corresponding to adiabatic flame temperatures less than ∼1500 K). Similar to comparisons of experiments from Qiao et al [7] and predictions of the present model and that of Li et al [12], the largest disagreement is observed at conditions that correspond to the lowest flame temperatures-reaching a factor of 2.7 at equivalence ratio 0.3 at 1 atm. Figures 28 and 29 show comparisons of laminar burning velocities extracted from measurements [5] and Egolfopoulos and Law [140]; solid lines the present model; dashed lines the model of Li et al [12].…”

“…While the model of Li et al [12] predicts burning rates within a factor of two of those measured by Burke et al [8,9], the present model predicts burning rates within 20% of those measured. Figures 25 and 26 show comparisons of laminar burning velocities extracted from more recent measurements of outwardly propagating flames using stretch correction by Qiao et al [7] and those predicted by the present model and that of Li et al [12]. Figure 25 shows the dilution dependence of the laminar burning velocity for H 2 /air/diluent flames of equivalence ratio 1.0 (Fig.…”

“…Closed symbols represent experimental data at normal gravity conditions, and open symbols represent experimental data at microgravity conditions from Qiao et al [7]; solid lines the present model; dashed lines the model of Li et al [12]. Closed symbols represent experimental data at normal gravity conditions, and open symbols represent experimental data at microgravity conditions from Qiao et al [7]; solid lines the present model; dashed lines the model of Li et al [12]. …”

“…A number of studies (e.g., [4][5][6][7][8][9][10][11]) have recently emerged that present experimental data at high-pressure and/or low-temperature conditions. Comparisons of these experimental data and model predictions using recently published kinetic models [12][13][14][15][16][17][18] reveal noteworthy disagreement, particularly for high-pressure and/or dilute flames [6][7][8][9]. Since the publication of many of these studies [4][5][6][7][8][9][10][11], Hong et al [19] published an updated H 2 /O 2 model on the basis of their recent shock tube measurements to determine improved rate constants for several reactions.…”

Research on Cellular Instabilities of Lean Premixed Syngas Flames under Various Hydrogen Fractions Using a Constant Volume Vessel

“…Up to now, a few studies have reported the cellular instabilities from experimental investigations; some scholars have studied the cellular instabilities of premixed hydrogen-air flames [25][26][27][28][29]. The cellular instabilities of mixtures of premixed hydrogen-hydrocarbon-air flames have also been studied by many scholars [30][31][32][33][34][35].…”