气流对飞秒激光加工炸药装药过程的热安全性影响分析

Due to the low thermal conductivity and high sensitivity to temperature of explosive, it is highly possible to form heat accumulation inside the explosive during the continuous processing of multi-pulse femtosecond lasers, leading to dangerous events such as ignition and combustion. To reduce the thermal effects during laser processing of materials, applying airflow is a common choice. To study the motion law of ablation products generated by explosive under the action of femtosecond laser and the temperature changes in explosive under the action of airflow, a two-dimensional fluid-solid coupling calculation model of femtosecond laser processing explosive under the action of airflow is established. Numerical simulation calculations are conducted on the process of processing cyclotetramethylene-tetranitramine (HMX) explosive using femtosecond laser under the action of subsonic airflow with different incidence angles on one or both sides. The calculation results show that a unilateral airflow will form a vortex flow on the surface of the explosive, causing the ablation products to rotate on the surface of the explosive, exacerbating the thermal effect of the ablation products on the explosive; The bilateral airflow will form a large vortex flow far from the surface of the explosive, causing the ablation products to leave the surface of the explosive quickly, effectively reducing the temperature of the explosive and improving the safety in the process of femtosecond laser processing explosive.