Development and Application of HEMSim: A Novel Thermochemical Code for Multiphase Combustion Analysis of Rocket and Gun Propellants

This study presents a comparison between HEMSim, a thermochemical code for energetic materials, and other thermochemical codes. The analysis focuses on the behavior of energetic materials under different regimes: isobaric combustion (rocket propellants) and isochoric combustion. HEMSim models complex multiphase systems, accounting for both condensed and gaseous products, with the gaseous phase described using a virial equation of state. In addition, the study examines the influence of the intermolecular potential model on the results, specifically comparing the widely used Lennard-Jones (L-J) potential with the more detailed Buckingham EXP-6 formulation. The goal is to assess whether the added complexity of the EXP-6 model leads to significant differences in the predicted thermodynamic properties. The results demonstrate the efficacy of HEMSim in capturing the thermodynamic behavior of propellants and provide valuable insights into the performance differences associated with varying potential models.