Numerical study on flashover in aircraft cargo under varying pressure and ventilation conditions

A numerical simulation study was conducted to analyze flashover in a full-scale aircraft cargo compartment, utilizing FDS (Fire Dynamics Simulator) and PyroSim (visual modeling) software. The study aims to: (i) examine how varying heat release rates (HRR), pressures, and vent sizes influence the hot gas layer temperature during flashover in confined spaces, and (ii) establish a semi-empirical model to predict flashover. Experimental results indicate that when the vent size is 1.86 m × 1.06 m and the pressure is 101 kPa, the minimum hot gas layer temperature required to trigger flashover is approximately 410 °C. When the pressure is reduced to 80 kPa and 60 kPa, the critical temperature increases to approximately 436 °C and 460 °C, respectively. These findings provide critical temperature benchmarks for predicting flashover in aircraft cargo fires. Furthermore, a semi-empirical engineering calculation model was developed to predict the hot gas layer temperature under various conditions during flashover. Validation against experimental data from the literature demonstrated good agreement (deviation of ≈20 %), confirming the model's applicability in diverse scenarios.