Optimization of a pyrotechnic igniter with the release of reactive particles

This paper deals with the effects of reactive particles on the performance of a pyrotechnic igniter. These particles are placed on the inner surface of a flash tube, released into the main flow of the gas and ignited by the passage of one of the two discontinuities (the shock wave or the contact surface). Two particle sizes have been studied (3m and 10m). It is shown that the best performance is achieved with small particles released into the flow by the shock wave. Another focal point of this study is the combining of two fundamentally different methods to calculate the two phase flow.Nomenclature a₀ sound speed in region 0 - a₂ sound speed in region 2 - C _D drag coefficient - d average particle diameter - d rate change of the particle diameter - e _g total internal energy of the gas - e _s particle internal energy=C ₃ T _s - F drag force - rn mass flow rate - Mo _c shock wave Mach number - N particle number desity - N _u Nusselt number - P pressure - P ₀ pressure in region 0 - P ₂ pressure in region 2 - P _r Prandtl number - Q heat convection - R _e Reynolds number - T _g gas temperature - T _s particle temperature - u ₂ velocity in region 2 - u _g gas velocity - u _s barycentric velocity of the particles - ratio of specific heats - _g thermal conductivity of the gas - _g gas dynamic viscosity - _g gas density - _s apparent density of the particles - _s true density of the particles - defined by (8) This article was processed using Springer-Verlag T_EX Shock Waves macro package 1990.