mechanism.

This presentation focuses on a comprehensive H₂/O₂/N₂ chemical kinetics mechanism and its validation for combustion at both atmospheric plus high-pressure and high-temperature operating conditions. This work is motivated by the lack of validated H₂/Air detailed kinetic mechanisms available for the prediction of NO_x species at high-pressure and high-temperature conditions. Only core H₂/O₂ mechanisms are available at these conditions but those do not enable the assessment of NO_x levels. On another hand, detailed mechanisms with NO_x as well as other species are available but only validated under atmospheric conditions. This presentation is centered on filling this gap to address the prediction of all species including NO_x at relevant operating conditions. The present mechanism development is based on available state-of-the-art experimental measurements and kinetics data. The developed mechanism consists of 33 species and 224 reactions. The method to develop this mechanism has three steps. The first step is to gather an experimental database including fundamental measurement data over a wide range of initial combustion conditions and various experimental devices. The second step is to update the key reaction rates and includes new reaction pathways to form a revised H₂/O₂ core mechanism. The evaluation of four widely utilized NO_x chemistry at both atmospheric and high-pressure conditions for stirred reactor and in-flame data is made to select a baseline. Finally, the last step is to combine both the updated core mechanism with the assessed nitrogen chemistry. The obtained mechanism is validated on a comprehensive data set for a wide range of inlet temperature and pressure for three selected targets: laminar flame speed, ignition time delay, and NO_x level. This process leads to a novel all-reactions and all-species mechanism for H₂/Air and H₂/O₂ mixtures combusting in future thermal-powered aircraft under high pressure and high-temperature conditions with hydrogen fuel.