Shock-Tube Study of Dimethoxymethane Ignition at High Temperatures

Autoignition delay time measurements were performed for dimethoxymethane/oxygen/argon mixtures at pressures of approximately 2, 4, and 10 atm, temperatures of 1103–1454 K, argon/oxygen dilution ratios of 11.25, 23.75, and 48.75, and equivalence ratios of 0.5, 1.0, and 2.0 in a shock-tube facility. Ignition delay times were determined using OH* emission and reflected shock pressure signals monitored at the shock-tube sidewall. The dependence of the ignition delay time upon the temperature, pressure, dilution ratio, and equivalence ratio was characterized. An empirical correlation for the ignition delay times with the experimental parameters was formulated by linear regression of these data. Experimental results were compared to the kinetic modeling predictions of two available chemical kinetic mechanisms to test the performance of mechanisms. Glaude’s mechanism yielded good agreement with the experimental results at 4 and 10 atm but underestimated the ignition delay times at 2 atm. Sensitivity analysis on ignition delay time was conducted, and the dominant reactions during the ignition process were identified. Better predictions on ignition delay times were achieved after modifying the reaction rate of selected small radical reactions. Moreover, fuel reaction pathway analysis was conducted to investigate the consumption of dimethoxymethane.