An experimental and modeling study on polyoxymethylene dimethyl ether 3 (PODE₃) oxidation in a jet stirred reactor

Polyoxymethylene dimethyl ether (PODE_n, n ≥ 1) is a class of oxygenated fuels containing unique carbon-oxygen chain structure and a promising alternative fuel for diesel engines. In this study, low-temperature oxidation characteristics of PODE₃ were studied experimentally and numerically. Experiments were performed in a jet-stirred reactor (JSR) at equivalence ratios of 0.5, 1.0 and 2.0, in the temperature range of 500 to 950 K, and at atmospheric pressure. Mole fractions of PODE₃, O₂, H₂, CO, CO₂, CH₃OH and C₁-C₂ hydrocarbons were measured by gas chromatograph (GC). Experimental measurements were compared with the simulation results based on two literature low-temperature oxidation models, denoted as the He model and the Cai model, respectively. Good agreement was obtained between the measured and simulated fuel consumption profiles, while a deviation was observed between the experimental and simulation results on the mole fractions of O₂ and intermediate products at medium temperatures. Reaction pathway analyses based on the two models were performed, revealing that the second O₂-addition reaction pathway is more significant in the prediction by the Cai model than that by the He model. Sensitivity analyses pointed out that the most important reactions affecting fuel consumption are the H-abstraction reactions of PODE₃, and the decomposition of H₂O₂ and the consumption of CH₂O become more sensitive at medium temperatures.