Shock tube and modeling study on autoignition properties of ammonia/diethyl ether mixtures at high temperatures.

• Measured ignition delay time of ammonia/diethyl ether mixtures using a shock tube. • Proposed a new ammonia/diethyl ether model (NH 3 –DEE). • Conducted kinetic analyses using the NH 3 –DEE model. Ammonia (NH 3) can be used as a fuel in gas turbines and internal combustion engines. However, it exhibits a long ignition delay time (IDT), which could be reduced by mixing highly reactive fuels with it. Few studies have been conducted on the IDT by adding diethyl ether (DEE) as a reactive fuel to NH 3 at high temperatures. Therefore, this study explores the influence of DEE on the autoignition characteristics and chemical kinetics of NH 3 using experimental, simulation, and theoretical approaches. The IDT of NH 3 /DEE mixtures were measured using a shock tube considering DEE fractions of 0 %, 5 %, 10 %, and 30 %, equivalence ratios of 0.5, 1.0, and 2.0, pressures of 0.14 and 1.0 MPa, and temperatures of 1220–1980 K. A new NH 3 –DEE model was developed and validated against experimental data, reliably predicting the IDT. Chemical reaction kinetic analysis using this model reveals a nonlinear decrease in the IDT of NH 3 with increasing DEE content, where adding only 5 % DEE reduced the IDT by over 80 %. The rapid consumption of DEE in the initial stages leads to the generation of numerous active radicals crucial for promoting NH 3 combustion. With the increase in DEE content, the reaction flux of DEE consumed through H-abstraction reaction increases. Additionally, increasing the proportion of DEE increases the mole fraction of CH 3 in the radical pool. This increase in CH 3 , when reacting with NH 2 , results in a higher concentration of cyanide, a highly toxic species. [ABSTRACT FROM AUTHOR]