Combustion waves in composite solid material of shell–core type

Abstract

In this article, an asymptotic and numerical analysis of combustion wave propagation in shell–core composite solid energetic material is undertaken based on the diffusional–thermal model with an overall Arrhenius reaction step. Flame speed and structure are found for a broad range of parameter values. Two different regimes of flame propagation are identified. In the weak recuperation regime, the temperatures of the shell and core are monotonic functions of the coordinates, and they differ only slightly in the reaction zone of the flame. In the strong recuperation regime, the temperature of the shell is significantly higher than that of the core and has a sharp peak in the reaction zone with the maximum value exceeding the adiabatic flame temperature for pure energetic material. It is found that the highest level of flame acceleration in the composite material can be attained in the strong recuperation regime. The competition of these flame propagation regimes may lead to the coexistence of multiple combustion waves travelling with different velocities. The stability is investigated of combustion waves in the practically important strong recuperation regime.

Keywords:

• combustion waves
• thermal–diffusive instabilities
• composite energetic materials
• flame multiplicity

Additional information

Funding

V. V. Gubernov and A. V. Kolobov would like to acknowledge financial support from the Russian Foundation for Basic Research [Grant No. 13-03-00282]. V. N. Kurdyumov would like to acknowledge the support of Spanish MEC [Grant No. ENE2011-27686-C02-01 and CSD2011-00011].