Ignition delay times of diethyl ether measured in a high-pressure shock tube and a rapid compression machine

Abstract

Ignition delay times of diethyl ether (DEE)/air/argon mixtures were studied in a shock tube in the temperature range from 900 to 1300K at pressures of 10, 20, and 40bar and in a rapid compression machine (RCM) at various equivalence ratios between 500 and 1060K at pressures between 2.5 and 13bar. Between 2.5 and 5.5bar, the RCM results show that ignition delay times of DEE exhibit a region (between 590 and 800K) where ignition delay times are weakly temperature dependent only, while above 833K and below 590K, the ignition delay times are strongly temperature dependent. Two-stage ignition was observed in the temperature range from 500 to 665K in the RCM measurements. At the conditions of the shock tube, a strong pressure and temperature dependence of the ignition delay times was observed, but no non-thermal (NTC) behavior was found in the investigated temperature range. Simulations based on detailed chemistry using the mechanism of Yasunaga et al. (2010) [15] indicate that at high pressures ignition delay times show a high sensitivity towards the two H-atom abstraction reactions by HO2 from diethyl ether. By increasing the rate coefficients of these two reactions relative to the original values by a factor of five, the mechanism well describes our measurements and still well reproduces the original data of Yasunaga et al. (2010) [15].