Hydrogen　and　ammonia　have　attracted　increasing　attention　as　carbon-free　fuels.　Ammonia　is　considered　to　be　an　effective　energy　storage　and　hydrogen　storage　medium.　However,　a　small　amount　of　unremoved　NH3　is　still　present　in　the　product　during　the　decomposition　of　ammonia　to　produce　hydrogen.　Therefore,　it　is　very　essential　to　investigate　the　self-ignition　of　hydrogen-ammonia　mixtures　in　order　to　accommodate　the　various　scenarios　of　hydrogen　energy　applications.　In　this　paper,　the　effect　of　NH3　addition　on　the　self-ignition　of　high-pressure　hydrogen　release　is　numerically　investigated.　The　RNG　k-Ε　turbulence　model,　EDC　combustion　model,　and　213-step　detailed　NH3/H2　combustion　mechanism　are　used.　CHEMKIN-Pro　programs　for　zero-dimensional　homogeneous　and　constant　volume　adiabatic　reactor　models　are　used　for　sensitivity　analysis　and　ignition　delay　time　of　the　chemical　reaction　mechanism.　The　results　showed　that　the　minimum　burst　pressure　required　for　self-ignition　increased　significantly　after　the　addition　of　ammonia.　The　maximum　temperature　and　shock　wave　intensity　inside　the　tube　decreases　with　increasing　ammonia　concentration.　The　ignition　delay　time　and　H,　HO2,　and　OH　radicals　reduce　with　increasing　ammonia　concentration.　H　and　HO2　radicals　are　suggested　as　indicators　for　tracking　the　second　and　third　flame　branches,　respectively.　©　2023　The　Authors