59053 - Ignition Delay Time Correlation of C1 – C5 Natural Gas Blends for Intermediate and High Temperature Regime 

New ignition delay time (IDT) data for stoichiometric natural gas (NG) blends composed of C₁ – C₅ n-alkanes with methane as the major component were recorded using a high pressure shock tube (ST) at reflected shock pressures (p₅) and temperatures (T₅) in the range 20 – 30 bar and 1000 – 1500 K, respectively. The good agreement of the new IDT experimental data with literature data at the same conditions enhances the importance of using the ST in validating chemical kinetic mechanisms. Comparisons of simulations using NUIGMech1.0 show very good agreement with these experimental results and also with existing data available in the literature. Empirical IDT correlation equations have been developed through multiple linear regression analyses for these C₁ – C₅ n-alkane/air mixtures using constant volume IDT simulations in the pressure range p_C = 10 – 50 bar, at temperatures T_C = 950 – 2000 K in the equivalence ratio (φ) range 0.3 – 3.0. Moreover, a global correlation equation, developed using NUIGMech1.0, to predict ignition delay times (IDTs) for these natural gas mixtures and other relevant data available in the literature. The correlation expression employs a traditional Arrhenius rate form including dependencies on the individual fuel fraction, T_C, φ and p_C.