Towards predictive simplified chemical kinetics for hydrogen detonations

Abstract

A methodology to develop predictive simplified kinetics schemes (one-step/three-step chain-branching) is presented in which detonation velocity-curvature (𝐷 − 𝜅) curves computed with detailed thermochemistry are used as the fitting target aiming to capture the turning point of the curve (𝜅crit). This was motivated by the similar trend observed between the 𝜅crit values obtained using the simplified schemes of Taileb et al. (2020), fitted using conventional methods, and the critical reactive layer heights for detonation propagation under yielding confinement (ℎcrit) reported by the same authors. Both updated schemes satisfactorily reproduce the target 𝐷 − 𝜅 curves and are used to (re)compute multidimensional cellular detonations propagating in channels and confined by inert layers. Simulations show a much better agreement with the results obtained with detailed kinetics for the detonation flow fields, cell sizes distributions, and ℎcrit. Moreover, it is observed that the average curvatures of the computed fronts are in line with those predicted by the 𝐷 − 𝜅 formulation, providing supporting evidence of the applicability of reduced order models for fast and inexpensive estimates of detonation limiting behaviors in safety studies