Numerical simulation on detonation initiation and propagation in supersonic combustible mixtures with nonuniform species

Cai, Xiaodong, Liang, Jianhan, Deiterding, Ralf and Lin, Zhiyong (2015) Numerical simulation on detonation initiation and propagation in supersonic combustible mixtures with nonuniform species. 20th AIAA International Space Planes and Hypersonic Systems and Technologies Conference, Glasgow, United Kingdom. 06 - 09 Jul 2015. 19 pp . (doi:10.2514/6.2015-3527).

Abstract

High-resolution numerical simulations of gaseous detonation initiation by means of a hot jet injection were conducted on detonation initiation and propagation in supersonic combustible mixtures with a spatially nonuniform species distribution adopting the adaptive mesh refinement open-source program AMROC. Three different groups of mixtures, which represent different rates of chemical activity, were investigated in total. The results show that when the mixtures in general have a high chemical activity, detonation initiation can be finally realized successfully both through the Mach reflection and the DDT mechanism in the flowfield, no matter how the mixtures are distributed in the channel. Four processes of detonation initiation, detonation attenuation, initiation failure and detonation re-initiation together make up periodical transition process with the help of the lateral expansion of the detonation. When the mixtures in general have an intermediate chemical activity, detonation combustion can be fully realized in the whole channel with different overdrive degrees in the upper half part and lower half part. After the shutdown of the hot jet, the overdriven detonation attenuates gradually, and finally a slightly strong detonation and a slightly weak detonation are formed together, which can be regarded as a new stable “CJ” state. However, whether detonation initiation can be realized or not in this case is determined by the distribution of different mixtures. When the mixtures in general have a low chemical activity, detonation initiation cannot be realized successfully. The reliable approach for the successful realization of detonation initiation in this case should be the application of a stronger hot jet.

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Contributors

Author: Ralf Deiterding

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