Numerical study of hydrogen ratio effect on detonation initiation characteristics of aviation kerosene with hydrogen addition

Abstract

Detonation initiation is one of the most important problems in the research of pulse detonation engine (PDE). It is difficult for aviation kerosene to meet the performance requirement of short-distance detonation initiation in PDE. Hydrogen can improve the detonability of fuels. Aviation kerosene with hydrogen addition provides a new method to shorten the detonation initiation distance in PDE. Therefore, hydrogen ratio effect on detonation initiation characteristics of hydrogen-doped aviation kerosene was studied by two-dimensional numerical simulation with the adoption of standard k-ε model, finite rate reaction model and simplified aviation kerosene/hydrogen/air reaction kinetics mechanism. The results indicated that hydrogen-doped aviation kerosene/air mixtures could not be successfully detonated with the minimum hydrogen ratio of 9.73 %, while the detonation was eventually initiated with higher hydrogen ratios, suggesting that the detonability of hydrogen-doped aviation kerosene was improved by increasing hydrogen ratio. The critical hydrogen ratio of 11 % was determined by further research. As the hydrogen ratio increased, the initiation time and distance of the plane detonation wave first increased slowly and then decreased rapidly, while the detonation velocity raised monotonically. The degree of spherical wave decoupling had an influence on the detonation initiation. Specifically, less spherical wave decoupling induced two Mach stems to propagate at the same time, which was conducive to accelerating the initiation of plane detonation.