Ignition of lean methane-based fuel blends at gas turbine pressures
Abbreviated Journal Title
J. Eng. Gas. Turbines Power-Trans. ASME
OXYGEN-ARGON MIXTURES; NATURAL-GAS; SHOCK-WAVES; AIR MIXTURES; PROPANE; COMBUSTOR; ETHANE; DELAY; TUBE; OXIDATION; Engineering, Mechanical
Shock-tube experiments and chemical kinetics modeling were performed to further understand the ignition and oxidation kinetics of lean methane-based fuel blends at gas turbine pressures. Such data are required because the likelihood of gas turbine engines operating on CH4-based fuel blends with significant (>10%) amounts of hydrogen, ethane, and other hydrocarbons is very high. Ignition delay times were obtained behind reflected shock waves for fuel mixtures consisting of CH4, CH4/H-2, CH4/C2H6, and CH4/C3H8 in ratios ranging from 90/10% to 60/40%. Lean fuel/air equivalence ratios (phi=0.5) were utilized, and the test pressures ranged from 0.54 to 30.0 atm. The test temperatures were from 1090 K to 2001 K. Significant reductions in ignition delay time were seen with the fuel blends relative to the CH4-only mixtures at all conditions. However the temperature dependence (i.e., activation energy) of the ignition times was little affected by the additives for the range of mixtures and temperatures of this study. In general, the activation energy of ignition for all mixtures except the CH4/C3H8 one was smaller at temperatures below approximately 1300 K (similar to 27kcal/mol) than at temperatures above this value (similar to 41 kcal/mol). A methanelhydrocarbon-oxidation chemical kinetics mechanism developed in a recent study was able to reproduce the high-pressure, fuel-lean data for the fuel/air mixtures. The results herein extend the ignition delay time database for lean methane blends to higher pressures (30 atm) and lower temperatures (11100 K) than considered previously and represent a major step toward understanding the oxidation chemistry of such mixtures at gas turbine pressures. Extrapolation of the results to gas turbine premixer conditions at temperatures less than 800 K should be avoided however because the temperature dependence of the ignition time may change dramatically from that obtained herein.
Journal of Engineering for Gas Turbines and Power-Transactions of the Asme
Article; Proceedings Paper
"Ignition of lean methane-based fuel blends at gas turbine pressures" (2007). Faculty Bibliography 2000s. 7521.