Pressure Effects on the Turbulent Consumption Speeds of High H2 Mixtures

摘要

This paper describes measurements and correlations of turbulent consumption speeds, S_(T,GC), of hydrogen/carbon monoxide (H_2/CO) fuel mixtures, with a focus on recently acquired elevated pressure data. Turbulent consumption speed data were obtained at mean flow velocities and turbulence intensities of 30 < U_0 < 50 m/s and 5 < u'_(mis)/S_(L,0)< 30,respectively, for H2/CO mixtures ranging from 30-90% H_2 by volume at 5 and 10 atm. Experiments were conducted where the mixture equivalence ratio, Φ, was adjusted at each fuel composition to have nominally the same un-stretched laminar flame speed, S_(L,0). In comparing two blends with the same composition, S_(L,0 ))value, and flow conditions, the 5 and 10 atm data have S_(T,GC) values that are consistently about 1.8 and 2.2 times larger than the 1 atm data, respectively. These data are also correlated with a scaling law derived from quasi-steady leading points concepts using detailed kinetics calculations of highly stretched flames. For a given pressure, these scalings do an excellent job in scaling data obtained across the H_2/CO fuel composition and fuel/air range. However, the pressure sensitivities are not captured by this scaling. This pressure sensitivity may be more fundamentally a reflection of the non-quasi-steady nature of the flame leading points. In support of this argument, we show that the spread in the data can largely be correlated with the ratio of a chemical time scale to a flow time scale.