Heat and momentum losses in H₂–O₂–N₂/Ar detonations: on the existence of set-valued solutions with detailed thermochemistry

The effect of heat and momentum losses on the steady solutions admitted by the reactive Euler equations with sink/source terms is examined for stoichiometric hydrogen–oxygen mixtures. Varying degrees of nitrogen and argon dilution are considered in order to access a wide range of effective activation energies, Ea,eff/RᵤT₀ E a,eff / R u T 0 , when using detailed thermochemistry. The main results of the study are discussed via detonation velocity-friction coefficient ( D – cf c f ) curves. The influence of the mixture composition is assessed, and classical scaling for the prediction of the velocity deficits, D(cf,crit)/DCJ D ( c f,crit ) / D CJ , as a function of the effective activation energy, Ea,eff/Rᵤ T₀ E a,eff / R u T 0 , is revisited. Notably, a map outlining the regions where set-valued solutions exist in the Ea,eff/RᵤT₀--α E a,eff / R u T 0 -- α space is provided, with α α denoting the momentum–heat loss similarity factor, a free parameter in the current study.