Measurements of Dielectric Properties of Condensed Phase Aluminized Composite Propellants

摘要

Advanced propellant combustion control technologies are required for progression of the solid propulsion field. Previous work has shown using propellants doped with alkali earth metals (e.g. sodium nitrate, NaNO_3), composite propellant flames can be made to have strong coupling with microwaves irradiation, and it has been demonstrated that using such a doping technique with sub-critical microwave excitation, the atmospheric burning rate of a composite solid propellant can be enhanced by 67%. Still, little literature exist on composite propellant condensed phase dielectric properties. In this study, the microwave properties of two aluminized ammonium perchlorate composite propellants being studied as candidates for microwave seeded plasma enhancement of propellant flames are considered. The dielectric properties of propellants are measured in the S-band between 2.3 and 2.65 GHz with an Anritsu Shockline vector network analyzer using the cavity perturbation technique. Using measured bulk propellant properties, finite difference models are developed to predict the field distribution within both a RF-modulated propellant strand combustion cavity and RF heating of the propellant utilizing COMSOL 5.1 Multiphysics to simulate conditions of propellants strand in a TE_(10n) mode cavity for an experiment in a continuous microwave cavity.