聚甲氧基二甲醚–2 燃烧动力学模型及试验研究

The combustion characteristics of polyoxymethylene dimethyl ethers-2 (PODE₂) at medium and low temperatures were investigated by kinetic modeling and experimental study. Following the rection class-based rate rules,a detailed reaction mechanism for PODE₂ was constructed according to the detailed mechanism of dimethoxymethane (DMM). The PODE₂ kinetic mechanism was validated against available literature experimental data. Ignition delay time of PODE₂ was measured in a rapid compression machine (RCM) platform in the temperature range of 650~900 K and at the equivalence ratios of 0. 5、1. 0、2. 0. The controlling factors of PODE₂ auto-ignition process at medium and low temperatures were analyzed in conjunction with the constructed detailed mechanism. The results show that the constructed PODE₂ reaction mechanism can well reproduce the experimentally measured ignition delay time. The PODE₂ auto-ignition shows a clear two-stage ignition phenomenon and does not exhibit any negative temperature coefficient(NTC) behaviors. The first-stage ignition delay time of PODE₂ varies linearly with temperature in the low temperature range,and shows a plateaus in the mid-temperature range of 720~820 K. The low temperature reactivity of PODE₂ is derived from three alternative channels,and the typical low temperature chain branching reaction sequence initiated by the oxygen addition reaction is inhibited.