Non-reactive shock tube data-based model to reproduce non-ideal gas-dynamics effects to predict ignition delay times

This study focuses on methods to correct the non-ideal behaviors of a gas following a reflected shock wave, as applied in chemical kinetic modeling. These non-ideal behaviors of gas were experimentally observed through an increase in the pressure (P5) of the inert argon gas behind the reflected shock wave. The impact of the initial temperature in the driven section (T1) and the concentration of a diatomic gas, O2, in argon on the P5 pressure trace is discussed. The experimental results show a negligible dependence between the rise in P5 pressure and both the initial temperature T1 (40–80 °C) and significant concentrations of O2, up to 25%. To account for facility-related non-ideal effects in chemical kinetic models, two methods found in the literature were analyzed, as well as the commonly used assumptions of constant volume or constant internal energy. Updated approaches are proposed to improve the prediction of both the ignition delay times and the evolution of pressure during fuel combustion by using pressure traces of argon as the test gas. The updated methods yielded promising results regardless of the fuel/O2/Ar mixtures for temperatures ranging from 825 to 1,700 K at 20 bar in a 50 mm internal diameter shock tube, especially below 1,200 K.