Ethyl Tertiary Butyl Ether Ignition and Combustion Using a Shock Tube and Spherical Bomb

Abstract

Ignition delay times and laminar flame speeds of Ethyl tertiary butyl ether (ETBE) were measured in both a shock tube and a spherical bomb, respectively. Ignition delay times of ETBE/O2/Ar mixtures were derived from OH radicals emission. Mixtures containing 0.1−0.4% of fuel were oxidized over the temperature range 1280−1750 K and for two different pressures, 0.2 and 1 MPa. The equivalence ratio was varied from 0.25 to 1.5. Furthermore, laminar flame velocities of ETBE/Air (79% N2 + 21% O2) mixtures were measured at room temperature and atmospheric pressure over an extensive range of equivalence ratios (0.5−1.5). The laminar flame speed measurements were performed in a spherical bomb using shadowgraph imaging system coupled to a high speed camera. Experimental results from both shock tube and spherical bomb were compared to those computed using a detailed chemical kinetic reaction mechanism. The mechanism used, containing 145 species and 998 reversible reactions, was validated earlier by simulating jet-stirred reactor (JSR) and on shock tube experiments on the oxidation of gasoline surrogate mixtures. The detailed chemical kinetic mechanism satisfactorily reproduces the experiments in shock tube at low pressure, but some improvements are required for relatively low temperature at high pressure. For the laminar flame velocities, the mechanism slightly over-predicts the experimental results around stoichiometric conditions. The main pathways and sensitivity analyses for ETBE oxidation under freely propagating flame and shock tube conditions were examined.