A high-pressure kinetics model for the ignition of natural-gas fuel blends Conference Paper uri icon

abstract

  • Shock-tube data and chemical kinetics simulations have been used to optimize a combustion mechanism for the ignition of methane-based fuel blends. This work is part of an on-going project to measure the combustion characteristics of natural-gas fuel blends at practical conditions. The model was assembled from various literature sources based on the well-known methane chemistry of GRI-Mech 3.0. Additional compounds and reactions were added to account for oxidation pathways that become important at gas-turbine operating pressures, i.e. 20-30 atm, and to model C2- and C3- compounds. The starting mechanism was updated with recent data, especially the H2/O2 mechanism and the enthalpy of formation of OH. Sensitivity and pathway analyses were used to identify the important elementary reactions, whose rates were then modified, within their experimental uncertainty, to best-fit experimental data collected at pressures from 10-50 atm and temperatures from 1000-1500 K. Results are presented for mixtures of H 2/O2/Ar, CH4/O2/Ar, CH 4/Air, CH4/H2/Air, and CH4/C 2H6/Air. The new model is able to reproduce the experimental ignition times for all mixtures over the range of conditions studied. While further work is planned to measure a broader range of fuels and blending, the present work documents the modeling process that will be used throughout and provides excellent performance at the conditions studied thus far. This model has practical applications in the design and operation of gas-turbine power generation systems and of propulsion systems operating at similar conditions.

author list (cited authors)

  • Hall, J. M., & Petersen, E. L.

publication date

  • December 2006