Ignition by hot gas jets

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Ignition of hydrogen/air mixtures by hot turbulent jets has numerous applications, including nuclear safety, pulse detonation engines, and explosion protection. This work focuses on explosion protection, presenting experimental and numerical investigations of the ignition process. An experimental setup featuring a combustion cell is used, where hot exhaust gas jets impinge on a quiescent hydrogen/air mixture, potentially initiating ignition. Laser diagnostics, including high-speed LIF sequences of hydroxyl radicals (OH) alongside Laser Schlieren visualization, provide spatial and temporal insights into ignition events. Numerical simulations of reactive mixing complement spectroscopic simulations of the OH-LIF signal to interpret results. A novel method combines LIF of seeded NO with numerical and spectroscopic simulations to measure the instantaneous 2D mixture fraction during ignition. Findings reveal the significant impact of hot jet temperature and mixing speed on ignition. High-speed OH-LIF sequences illustrate flame quenching in the nozzle and subsequent ignition. The study also explores two configurations—ignition and non-ignition—capturing the axial decay of jet fluid concentration and axisymmetric radial profiles. Mixture fraction plots reveal distinct mixing behaviors near the jet tip and radial sides. The report discusses limitations and alternative strategies for measuring mixture fraction. The experimental data wil