Study on the Risk and Early Warning of Modified Double-Base Propellant Catastrophic Combustion at Different Process Temperatures

To better understand accidental combustion during MDB propellant production, we studied the combustion behavior at different process temperatures using point-source ignition. The ignition delay, flame morphology, temperature evolution, thermal radiation, and spectral characteristics were analyzed. At 120 °C, the ignition delay was shortened by approximately 110 ms compared to that at 30 °C and approximately 50 ms compared to that at 80 °C. The flame area and radiation intensity increased, with peak values advancing by 42.5 and 21.5%, respectively. The extinguishing time decreased, while the maximum temperature remained at approximately 1130 °C. Flames were consistently detected above 600 °C. Distinct spectral bands were observed, including Na D (588.9 nm), K (766.4, 770.0 nm), and IR bands at 861.5 and 1991.3 nm. At 120 °C, detectable signals at 588.9 and 766.4 nm appeared within 10 ms and reached 65 082 au in 40 ms, providing reliable flame indicators. Higher process temperatures significantly increase the combustion hazard by shortening the ignition delay, enlarging the flame area, accelerating the burning rate, and intensifying the thermal radiation. The ∼600 °C threshold, IR spectral bands, and temperature serve as early warning signals, while visible wavelengths offer key flame-detection indicators. These findings establish a scientific basis for accident prevention and combustion control strategies in MDB propellant production.