Effect of Hydrogen Peroxide Addition on the Modal and Thermochemical Response of a Hydrogen–Oxygen Rotating Detonation Engine

Rotating detonation engines (RDE) are compact pressure-gain combustors whose practical operation depends on maintaining coherent coupling among rotating-wave propagation, mixture replenishment, ignition, and heat release. This computational study examines whether a low-level hydrogen peroxide ( H 2 O 2 ) addition can act as a reactivity modifier in a nitrogen-diluted H 2 / O 2 RDE. Five 2D unwrapped-domain simulations are compared: a baseline case without H 2 O 2 and four additive cases from 1% to 4%, with the geometry, boundary conditions, initialization, mesh, and numerical settings kept fixed. The baseline case sustains a single rotating detonation wave and provides the reference state for the additive sweep. For 1%–3% H 2 O 2 , the combustor response changes only modestly: the dominant pressure frequency and frequency-inferred wave speed increase slightly; but pressure amplitude, cycle regularity, near Zel’dovich–von Neumann–Döring (ZND) pressure persistence, cumulative heat release, and supplied-mass-normalized heat release remain bounded and nonmonotonic. At 4% H 2 O 2 , the combustor transitions to a weaker dual-wave detonation mode. Although the dominant pressure frequency nearly doubles, the frequency-inferred wave speed decreases relative to its corresponding ideal Chapman–Jouguet velocity, and the pressure amplitude, near-ZND pressure persistence, pressure–heat-release timing consistency, and heat-release intensity all weaken. Region-level species diagnostics show that the 4% case has the largest mean OH and aggregate radical pool, but this reactive radical pool does not translate into stronger pressure or heat-release coupling. Within this controlled numerical configuration, the results show that H 2 O 2 -induced chemical sensitization alone does not guarantee improved RDE operation. The findings therefore suggest that additive levels should be assessed as coupled combustor states, using modal, pressure, heat-release, and species/radical diagnostics rather than chemical reactivity arguments alone.