Screening of metal fuels for use in composite propellants for ramjets

A review of the literature on the methods for activation of the combustion of metallic fuels, mainly boron-containing ones, as the promising components of composite propellants for ramjets is presented. Some methods and ideas were checked experimentally using a laboratory approach developed for comparing the metallic fuels (MF) of different origin. The approach implies the determination of the set of propellant combustion parameters, such as: burning rate, mass of condensed combustion products (CCP), MF combustion completeness, and heat release efficiency (HRE). The CCP particles are firstly quenched in an inert gas, and then sampled and subjected to particle size and chemical analyses. Seventeen propellants, containing different fuels, were studied at pressures of 1.2 and 2.5 МPа. The formulation factors that affect the burning rate and HRE were revealed. Recommendations on future directions of the studies on promising propellant formulations are given.