Simulation Study on the Thermal Safety of Ammunition in a Multifunctional Launch Vehicle Fire

The multifunctional launch vehicle caught fire due to an unexpected fuel tank fire, creating a fierce flame-burning environment for the onboard ammunition, and posing a huge threat to operators and launch platforms. In order to obtain the thermal safety performance of vehicle-mounted ammunition in case of vehicle fire, the Russian SS-23 missile was taken as the research object. First, the fire dynamics software FDS was used to calculate and analyze the flame structure characteristics and the change law of ammunition ambient temperature field at different stages of fire development. Then the fluid dynamics software CFD was used to calculate and analyze the temperature field distribution characteristics and thermal stimulation response law of ammunition charge. The research results indicate that the uneven distribution of the flame temperature field formed when the fuel tank accidentally catches fire can cause a complex heating environment for on-board ammunition; The internal charge of ammunition continues to heat up under the combined effect of external heating and self-generated heat, and the high-temperature zone shifts towards the interior of the charge, further accelerating the decomposition and heat accumulation of the explosive, ultimately leading to the reaction of the warhead charge. At the same time, different residual fuel levels in the main fuel tank and different wind directions will have an impact on the firing process of the launch vehicle, and the reaction time and position of the onboard ammunition will also vary.