
Abstract Flame surface characteristics were measured in turbulent premixed flames of hydrogen-enriched methane–air mixtures at elevated pressures. The equivalence ratio range was from 0.6 to 0.8 and the hydrogen mole fraction in the fuel was varied from 0 to 0.2. The pressure range covered from atmospheric to 0.9 MPa. Planar Mie scattering measurements were performed to obtain the flame front images, which were further analyzed for fractal parameters, flame front curvature statistics, and flame surface density. Non-dimensional turbulence intensity, u′/SL, changed in proportion to the pressure and was 1.53 at atmospheric pressure and 6.51 at 0.9 MPa. With increasing pressure the flame images displayed finer structures indicating that the flame surface area was increasing with pressure. This was also indicated by the probability density function of the flame front curvature as a function of the pressure. Fractal dimension showed a strong dependence on pressure and increased from about 2.1 at atmospheric pressure to about 2.25 at 0.9 MPa. Fractal parameters, including inner and outer cut-offs, agree to a certain extend with the previous experimental data obtained at atmospheric and elevated pressures. The sensitivity of the fractal dimension to u′/SL was found to depend on the way u′/SL was varied. A strong correlation between the inner cut-off scale and the average flame radius of curvature was demonstrated. The implications of these results for flame surface density estimations are discussed.
Fractal characteristics of premixed flames, Hydrogen-enriched methane flames, Combustion, Surface density of high-pressure flames, [SPI.FLUID] Engineering Sciences [physics]/Reactive fluid environment, Premixed turbulent combustion, High-pressure premixed turbulent flames, Hydrogen
Fractal characteristics of premixed flames, Hydrogen-enriched methane flames, Combustion, Surface density of high-pressure flames, [SPI.FLUID] Engineering Sciences [physics]/Reactive fluid environment, Premixed turbulent combustion, High-pressure premixed turbulent flames, Hydrogen
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 35 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
