Combustion and plume-plasma characteristics of cesium-based solid propellant

Abstract

The high-temperature plume of solid propellant has spawned considerable amount of highly ionized plasma, which can be used to increase the specific impulse of propellant with the external physical field, as well as serve as the charged particles for the magnetohydrodynamic (MHD) generator on the thruster. Unfortunately, the deficiency of workable deal to promote the electrical performance of the plume hinders the development of the above technologies. In this work, cesium-based composite solid propellants (CCSP) were designed and fabricated by introducing cesium-based oxidants into the AP/HTPB/Al propellant as the highly ionized seed. The propulsion properties and plume conductivity of CCSP were preliminarily calculated through theoretical method. The comprehensive combustion-plasma characteristics (plume conductivity, flame morphology and combustion temperature) of CCSP were further investigated, utilizing plume-plasma diagnostic system. Profiting from the high electron derailment capacity of cesium atom with high temperature, the density of charged particles in the plume of CCSP significantly multiplied. The conductivity of CCSP plume with a value of >1000 S/m presented several orders of magnitude enhancement compared with the plume of baseline propellant (3.9 S/m). Additionally, partially replacing AP with CN/CP contributed to the combustion adequacy of Al MPs. The investigation on the burning rate pressure-index of CCSP and baseline using the high-pressure combustion chamber indicated that 0<nbaseline<nCCSP<1, proving the application ability on SRM and the ability to regulate the burning rate over a wide pressure range for CCSP. Overall, the presented work provided a novel method for improving the plume-plasma performance of propellant, exhibiting the admirable application prospects for Rocket-MHD generator technology and enhancement technology of thrust/specific impulse by physical energy field.