Investigation of CL-20/NEPE propellant: thermal decomposition, ignition and combustion characteristics

Abstract

CL-20/NEPE propellants, due to their high energy levels, superior combustion performance, and low signature characteristics, hold significant application value in the field of propellant technology. However, their thermal decomposition, ignition and combustion characteristics are highly complex, necessitating a deeper understanding. In this study, a thermal gravimetric analyzer was deployed to study the thermal decomposition characteristics of CL-20/NEPE propellant, and then a high-pressure combustion chamber was established to observe the ignition process and combustion characteristics. The thermal decomposition of CL-20/NEPE propellant was observed to occur in three phases: low-temperature rapid mass loss stage (50 °C–280 °C), medium-temperature slow mass loss stage (290 °C–400 °C), and high-temperature slow mass loss stage (400 °C–500 °C). The propellant undergoes five phases during ignition and combustion: initial flame formation, flame diffusion, steady combustion, flame recession, and flame extinction. The microstructure of condensed combustion products post-combustion was analyzed using a scanning electron microscope, we broadly categorized the CCPs into three types according to their morphology. Finally, we constructed an agglomeration model predicated on the pocket model to forecast aluminum agglomerate sizes within CL-20/NEPE propellant. The experimental data closely match the model's predictions, validating the model's efficacy in agglomeration prediction for this propellant.