Research on aluminum agglomeration characteristics of Al/NEPE propellant

Abstract Adding aluminum particles to solid propellants is used to improve the energy density of the propellant and the specific impulse of the engine. However, the aluminum particles will agglomerate to form large-sized condensed combustion products, which can cause nozzle erosion and two-phase flow loss. Therefore, it is necessary to study the aluminum agglomeration characteristics of solid propellants. In this paper, the combustion process of the Al/NEPE propellant was recorded by a high speed camera and a fiber optic spectrometer, and the condensed combustion products of the propellant were collected. The microstructure of the condensed combustion products was analyzed by a scanning electron microscope coupled with energy dispersive (SEM-EDS). These results show that the agglomeration process of aluminum particles may go through three stages: accumulation, aggregation and agglomeration. The condensed combustion products are mainly divided into aluminum agglomerates and smoke oxide particles. Generally, the size of agglomerates exceeds 50 μm, while the size of smoke oxide particles is less than 1 μm.