Research on the combustion mechanism of jet ignition engine fueled with ammonia-hydrogen

Jet ignition is a key ignition technology to improve the ignition and combustion of ammonia internal combustion engine. To achieve better design of jet ignition, the combustion mechanism of jet ignition is numerically studied. Firstly, a zero-dimensional jet ignition engine model is developed based on SENKIN. Then, the jet ignition mechanism of the stratified jets during the jet entrainment process is investigated through the dilution of the jet with various volumes of fresh mixture. Based on the validated model, the influence of the structural parameter of the jet chamber, key radicals, thermal and chemical effects on jet ignition are further revealed. The results show that a slow low-temperature exothermic stage is observed before auto ignition of the jets during the entrainment process. Through the quenching comparison between key radicals, (O) over dot is the most crucial radical to jet ignition. The reaction path of consuming and producing O(H) over dot could be affected by changing the parameter of the jet chamber, resulting a different ignition behavior. Successful jet ignition is the synergistic combination of thermal and chemical effects. The thermal environment established by the jets facilitates chemical reactions, while the heat released from these reactions further amplifies the thermal effect, ensuring the sustainability of the ignition process.