Study of the features of oblique detonation induced by a finite wedge in hydrogen-air mixtures with varying equivalence ratios

摘要

This paper provides a numerical investigation of the features of an oblique detonation process induced by a finite wedge in hydrogen-air mixtures with varying equivalence ratios. The reactive N-S equations with a detailed chemical model are solved to simulate the flow field characteristic of ODW (oblique detonation wave). This paper focuses on the effects of the equivalence ratios and expansion waves, including the initiation characteristics, wave structures, density, and temperature distributions on the ODW. Numerical results demonstrate that the mixtures near the stoichiometric condition have a better performance on the initiation of detonation, both the conditions of lean combustion and rich combustion will result in the no-initiation of oblique detonation. The increasing length of the oblique wedge L-w increases the scope of detonation initiation. It means a decrease in the lower initiation limits and an increase in the upper initiation limits of ODW for different equivalence ratios. The effects of expansion wave on ODW are significant in that the decreased L-w increases the characteristic length in the induction zone at the low and high equivalence ratios.