Abstract
<jats:p>Hydrogen has strong potential as a fuel for advanced pressure-gain combustion due to its high energy density, rapid reaction kinetics, and emission-free combustion. In this study, numerical analysis with Cantera software was carried out to evaluate the impact of equivalence ratio (Φ = 0.2–2.0) and initial pressure (1–5 bar) on Chapman–Jouguet (CJ) detonation parameters, Zel'dovich–von Neumann–Döring (ZND) reaction characteristics, and equilibrium concentrations of species and radicals in hydrogen–air mixtures. The results show that the peak CJ temperature and pressure occur in slightly rich mixtures (Φ ≈ 1.0–1.1). An increase in initial pressure leads to a substantial rise in detonation pressure, with values reaching up to 80 bar at an initial pressure of 5 bar. Elevated initial pressures result in shorter induction and exothermic reaction zones and shift the thermicity peak closer to the leading shock front. The equilibrium species and radical concentration profiles demonstrate increased H2O production and reduced levels of H, O, and OH radicals as pressure increases, highlighting the critical role of P0 in governing detonation chemistry. These outcomes provide a basis for optimizing hydrogen detonation performance and advancing the development of efficient, high-performance pressure-gain combustion systems.</jats:p>