A computational study and correlation of premixed isooctane-air laminar reaction front properties under spark ignited and spark assisted compression ignition engine conditions

作者：Martz J B^*; Middleton R J; Lavoie G A; Babajimopoulos A; Assanis D N

来源：Combustion and Flame, 2011, 158(6): 1089-1096.

DOI：10.1016/j.combustflame.2010.09.014

• Spark ignition
• HCCI
• Spark assisted compression ignition
• Low temperature combustion
• Laminar burning velocity
• Isooctane

To address the need for reliable premixed laminar burning velocity and thickness information within the spark assisted compression ignition (SACI) combustion regime, a large dataset of simulated reaction fronts has been generated in this work. A transient one dimensional premixed laminar flame simulation was applied to isooctane-air mixtures using a 215 species chemical kinetic mechanism. The simulation was exercised over fuel-air equivalence ratios, unburned gas temperatures and pressures ranging from 0.1 to 1.0, 298 to 1000 K and 1 to 250 bar, respectively, a range that extends beyond that of previous researchers. Steady reaction fronts with burning velocities in excess of 5 cm/s could not be established under all of these conditions, especially when burned gas temperatures were below 1500 K and/or when characteristic reaction front times were on the order of the unburned gas ignition delay. Steady premixed laminar burning velocities were correlated using a modified two-equation form based upon the asymptotic structure of a laminar flame, which produced an average error of 2.5% between the simulated and correlated laminar burning velocities, with a standard deviation of 3.0%. Additional correlations were constructed for reaction front thickness and adiabatic flame temperature. The resulting premixed laminar burning velocity correlation showed good agreement with experiments and existing correlations within the spark-ignited (SI) regime. Analysis of the simulated characteristic reaction front times and ignition delays suggests that homogeneous SACI combustion is most useful under medium and high load operating conditions.

• 出版日期2011-6