Chemical behavior research of high-energy aerospace propellant with a mesoscale heterogeneous packing model

Abstract

The NEPE propellant has a wide range of applications in the aerospace field, playing a crucial role in enhancing the performance and efficiency of propulsion systems. In this study, we have developed an elaborate physical–chemical model to simulate the transient reaction characteristics of NEPE propellants. Our approach entails a sequential algorithm to explore the microstructure of NEPE propellants, incorporating a novel semi-global kinetic reaction mechanism designed to accurately represent real-world scenarios during propellant combustion. The interplay between the condensed phase and gas phase is handled through the use of the source term method. A comprehensive examination is carried out to ensure the statistical convergence of the propellant particle distribution. Moreover, we have compared the simulated burning rate of NEPE propellant under different formulations and operating pressures (ranging from 0.5 to 2.5 MPa) with experimental cases. The predictions demonstrate excellent agreement within a 10 % margin of the experimental data, highlighting the precision with which our proposed model depicts propellant combustion. Furthermore, we have conducted simulations of the combustion of specific NEPE disk packs composed of 19.63 % 100 µm AP, 35.3 % 60 µm HMX, 8.83 % 50 µm HMX, and 36.25 % NG/BTTN binder. Our findings reveal that the variation of statistical burning rates can be described by the equation rb=3.93P0.453, Additionally, the adiabatic flame temperature of the disk packs, under various pressures, typically falls within the range of 3200–3700 K. To gain a deeper understanding of the impact of different components within the propellant on combustion, we have carried out burning tests on a series of NEPE disk packs with varying formulations, accompanied by particle-scale combustion analysis. Our observations indicate that substituting 1 % HMX particles for AP particles leads to a significant enhancement in the propellant’s burning rate, approximately 0.02 mm/s. This phenomenon confirms that HMX particles act as a potent explosive source, thereby contributing to an increased flame standoff distance. Consequently, a jet-like diffusion flame with a length scale of several microns commonly appears above the AP-binder-HMX unit.