Numerical simulation on the compartment safety of solid propellant storage under accidental jet fire

Abstract

During the storage process of solid rocket motors (SRM), unintentional operations may lead to uncontrolled internal propellant combustion, which threatens to adjacent rocket motors and results in catastrophic outcomes. Consequently, the safety of storing SRM is a critical concern. In this paper, the Computational Fluid Dynamics (CFD) numerical simulation method is applied. The structure and flow parameters of the flow field are obtained using the Naiver-Stokes (N-S) control equations, the Realizable k-epsilon turbulence model, and the finite rate model. We investigate the hazardous properties of a standard storage compartment equipped with an exhaust cover and spray system in the event of an accidental jet fire. Furthermore, the safety parameters of the storage compartment are examined. The results showed that the jet flame was initially directed at the side walls, spread to the upper part, and propagated throughout the storage compartment. Using the response times and thresholds of the temperature and pressure sensors, the study determined the optimal activation time for the pressure relief port and water spray system to be 0.4 s and 0.1 s, corresponding to a spray intensity of 0.5 kg/s. The synergistic effects of the pressure relief exhaust cover and spray mechanisms could quickly reduce the temperature of the compartment below the critical threshold of 500 K, thereby preventing thermal hazards associated with propellant combustion within 10 s. The optimal location and time of entry into the storage compartment are determined based on monitoring the mass fraction of gases in the compartment while maintaining temperature and pressure safety limits. The results will provide theoretical foundations for improving secure memory design practices on SRM.