Ignition Of Methane/Ethane/Propane Mixtures At Engine Pressures

Shock-tube experiments were conducted to investigate and further understand the impact of higher-order hydrocarbons on methane-based fuels at elevated pressure. Measurements of ignition times behind reflected shock waves were obtained for methane/ethane/propane/air mixtures; the mixtures were methane-based (70-90% by volume), and ethane and propane were varied from 7- 20% and 3-15%, respectively. The pressures, temperatures, and equivalence ratios varied from 1 to 58.6 atm, 1032 to 1577 K, and 0.5 to 2, respectively. The results show the effects of pressure, temperature, stoichiometry, and hydrocarbon content on the combustion chemistry of the blends. From the parametric analysis on the ignition data, in which equivalence ratios and mixture compositions were varied, it was determined that hydrocarbon content has a much greater impact on ignition delay time than does fuel mixture stoichiometry. Ignition delay time increases with increasing equivalence ratios over a comparable range of temperatures