Leng, YupengJi, XiangZhang, ChengchengSimms, NigelDai, LimingYu, Chunkan2024-03-212024-03-212024-03-12Leng Y, Ji X, Zhang C, et al., (2024) Numerical study of premixed PODE3-4/CH4 flames at engine-relevant conditions. Fuels, Volume 5, Issue 1, March 2024, pp.90-106https://doi.org/10.3390/fuels5010006https://dspace.lib.cranfield.ac.uk/handle/1826/21056Polyoxymethylene dimethyl ether (PODEn, n ≥ 1) is a promising alternative fuel to diesel with higher reactivity and low soot formation tendency. In this study, PODE3-4 is used as a pilot ignition fuel for methane (CH4) and the combustion characteristics of PODE3-4/CH4 mixtures are investigated numerically using an updated PODE3-4 mechanism. The ignition delay time (IDT) and laminar burning velocity (LBV) of PODE3-4/CH4 blends were calculated at high temperature and high pressure relevant to engine conditions. It is discovered that addition of a small amount of PODE3-4 has a dramatic promotive effect on IDT and LBV of CH4, whereas such a promoting effect decays at higher PODE3-4 addition. Kinetic analysis was performed to gain more insight into the reaction process of PODE3-4/CH4 mixtures at different conditions. In general, the promoting effect originates from the high reactivity of PODE3-4 at low temperatures and it is further confirmed in simulations using a perfectly stirred reactor (PSR) model. The addition of PODE3-4 significantly extends the extinction limit of CH4 from a residence time of ~0.5 ms to that of ~0.08 ms, indicating that the flame stability is enhanced as well by PODE3-4 addition. It is also found that NO formation is reduced in lean or rich flames; moreover, NO formation is inhibited by too short a residence time.en-UKAttribution 4.0 InternationalPODE/CH4 mixtureignition delay timelaminar burning velocitykinetic analysisperfectly stirred reactorArticle2673-3994