Explosion Hazard of AP/HTPB in Fire Condition

To study the thermal stability of solid propellant, a temperature model of pool fire is built to replace the uniform temperature rise model in previous studies. The model can better show the effect of different fire stages on solid propellant. Based on the AP/HTPB cook-off model, an effective method to evaluate the thermal safety of propellants is proposed by changing the heating distance and shell thickness. The thermal explosion process of AP/HTPB in fire conditions is numerically simulated, and the ignition temperature and ignition delay time are predicted. The results show that the ignition delay time increases and the ignition temperature decreases with the extension of heating distance. When the distance exceeds 500 mm, the ignition delay time increases rapidly and the ignition temperature remains stable at about 560 K. The shell thickness has an obvious effect on the ignition delay time, but has little effect on ignition temperature. The ignition delay time increases by 25% for each 2 mm increase in shell thickness. The simulation results fit the experimental data well, which provides a reliable reference for the assessment of the explosion hazard of AP/HTPB in fire conditions.