Interdisciplinary combustion issues in electrically controlled solid propellant

Abstract

A novel rocket fuel for intelligent solid propulsion system, electrically controlled solid propellant (ECSP), with on-demand on-off capacity and programmable thrust output characteristics, is attracting substantial attention due to conquering the inherent self-sustaining combustion defect of traditional solid propellant. Regrettably, the coupling effects of the external physical energy field, pressure, and electrochemistry have compounded the complexity of combustion chemistry, hindering the technology from gaining widespread support. Herein, the comprehensive combustion characteristics (involving ignition/extinguishment delay, burning rate, mass loss, and dynamic-diffusion flame transition) of propellant was investigated with synchronous elevating pressure and voltage, utilizing a lab-designed high-pressure electrically controlled combustion diagnosis system. Importantly, we proposed a seminal voltage-dominated dual-index burning rate model ($r=a{\left(f\left(U\right)\right)}^{n_1}{p}^{n_2}$ ($0<n_1=0.8081,n_2=0.1427<1$)) through the electrode-interface heterogeneous reaction kinetics, demonstrating that the burning rate can be precisely regulated by the active voltage-control without compromising the operation stability of solid rocket motor (SRM). Targeted investigation of the interface evolution revealed hyperthermic interface could trigger self-sustaining combustion.