Prediction of half reaction length for H 2 –O 2 –Ar detonation with an extended vibrational nonequilibrium Zel'dovich −von Neumann −DÖring (ZND) model

Abstract

An extended Zel'dovich–von Neumann–Döring (ZND) model has been proposed to address vibrational nonequilibrium mechanism. To expand the application of this extended ZND model in predicting flow characteristics under thermal nonequilibrium for hydrogen-related detonation simulations, a case of one-dimensional stoichiometric hydrogen-oxygen detonation with argon dilution is adopted for comparative study. A vibrational relaxation timescale is introduced in the extended ZND model together with simplified single-step and two-step chemical reaction models. In addition, a numerical simulation using the conservation element and solution element (CE/SE) algorithm and detailed chemistry with vibrational nonequilibrium coupling is conducted to serve as a benchmark for the model predictions. In this specific case study, predictions of half reaction length are in good agreement with simulations if the single-step Arrhenius model and the characteristic vibrational temperature of hydrogen are used. Compared with the detailed numerical simulations, the current extended ZND model and the simplified chemical models are demonstrated feasible and economical to predict the half reaction thickness under the vibrational nonequilibrium condition and can serve as one of the analytical tools in studying large-scale H 2 –O 2 detonation.