Fluid-structure interaction modelling of propellant combustion

Abstract

The controlled combustion of solid propellants is vital to rocket motor design, weapon system design and gas generators used for airbag inflation and fire suppression. Given the characteristics of any propellant and structural system, a model of combustion should be able to establish the energy release and corresponding pressure generated by the propellant on the system. Due to inherent complexities associated with propellant ignition and combustion, the description of propellant burn and consequent impact on structural design is not well understood. This article investigates the nature of propellant burn through the development of a computer simulated model. More specifically, governing equations of solid propellant combustion based on the Nobel--Abel equation of state are introduced into a finite element environment to perform fluid-structure interaction modelling on the system. The Nobel--Abel Equation of State in conjunction with a steady state burning law, which describes the recession rate of the burning propellant, is incorporated into a finite element environment through a user subroutine. The fluid-structure interaction capabilities allowed for the impact of the evolving gasses on the structure of the system to be analysed. The derived model empowered the analysis of a wide range of system parameters their effect on system performance. Results of material stress/\penalty \exhyphenpenalty strain and fluid dynamics are presented.