密闭空间内爆炸载荷抑制效应实验研究

炸药在密闭空间内爆炸时的爆炸载荷与在敞开环境中有很大差异，在密闭空间内，TNT炸药的爆炸产物能够与周围空气充分混合并发生燃烧反应进而释放额外的能量，使密闭空间内的反射冲击波及准静态压力均明显增加。为探究不同气体环境对密闭空间内爆炸载荷的抑制效应，开展了3种不同药量的TNT分别在空气、水雾和氮气环境密闭空间内的爆炸实验研究，通过理论计算和实验对比分析了密闭空间内的爆炸载荷压力、温度及受载钢板试件响应特性。结果表明，水雾和氮气均能有效降低空间内的准静态压力和温度，对准静态压力的平均降幅分别为36.0%和51.7%，对温度的平均降幅分别为42.6%和40.3%；在水雾和氮气环境中的爆炸载荷作用下，钢板试件动态响应较空气环境中显著降低，其中160 g药量下，水雾和氮气环境中钢板试件的最终变形分别减少了15.9%和23.5%，氮气的减弱效果优于水雾；水雾和氮气均能及时有效地抑制封闭空间内的爆炸载荷，降低结构的损伤程度。

Experimental study on the mitigation effects of confined-blast loading

The blast loading from an explosion in a confined space is quite different from that in an open environment. The detonation products of TNT can be fully mixed with the surrounding air, and release additional energy through combustion effect, resulting in a significantly increase of the reflected shockwaves and quasi-static pressure in the confined space.In order to investigate the mitigation effect of different atmosphere on explosion load in confined space, the experimental tests of TNT with three different charge masses were performed in a fully confined chamber filled with air, water mist and nitrogen, respectively. The explosive load pressure, temperature and the response characteristics of blast-loaded steel plates in the confined space were analyzed by theoretical calculation and experiment. The results show that both the water mist and the nitrogen can effectively reduce the reflected shock wave, the quasi-static pressure and the temperature in the confined chamber. The average reduction rate of quasi-static pressure is 36.0% and 51.7%, and the average reduction rate of temperature is 42.6% and 40.3%, respectively. The ideal gas state equation was used to calculate the theoretical value of quasi-static pressure in the confined space filled with nitrogen. It is found that the theoretical value is slightly larger than the experimental value, which is due to the insufficient combustion of detonation products in the test. The dynamic response of blast-loaded steel plates in water mist and nitrogen atmosphere is significantly lower than that in the air condition, and the residual deformation of the steel plate at 160 g TNT in water mist and air conditions, the attenuating effect of nitrogen is better than that of water mist. It is revealed that the mechanism of the water mist and nitrogen in mitigating the confined blast load and the subsequent dynamic response of structure is restraining the energy release from the combustion of the detonation products. The conclusions can provide references for the design of anti-blast structure.