Laminar flow reactor experiments for ignition delay time and species measurements at low temperatures: Linear alkanes and dimethyl ether

A laminar flow reactor has been developed for measurements of first stage ignition delay times and intermediate species at low temperatures. The design concept, technical details, and data evaluation schemes are presented and discussed in detail. Ignition delays of up to one second can be measured in the laminar flow reactor, which extends the measurement range of rapid compression machines and shock tubes significantly. First stage ignition delay time measurements were performed for a wide variety of fuels with well-validated low temperature chemistry to provide the initial classification of the laminar flow reactor. Further, the low temperature asymptote was clearly measured for the investigated fuels. For the linear alkanes n-pentane, n-hexane, n-heptane, and n-decane, as well as for dimethyl ether, ignition delay times were obtained at stoichiometric condition and atmospheric pressure. These ignition delays were compared against recent kinetic models and experimental data from the literature. Very good agreement was found for n-pentane, n-decane, and dimethyl ether. Interestingly, the agreement is less satisfactory for n-hexane, whose model (Zhang et al., 2016) is hierarchically built on the n-pentane model (Bugler et al., 2015) and for n-heptane, which is modeled using the same n-alkane reaction mechanism (Cai et al., 2016) as for n-decane. For n-heptane, the agreement with the ignition data of Campbell et al. (2015) is far better than the agreement with the model. (C) 2018 Published by Elsevier Inc. on behalf of The Combustion Institute.