Study on the propagation and distribution of blast waves along the axial direction of the explosion venting vessel

Blast waves along the direction of explosion venting generated by an explosion in a partially confined space are characterized by high and multi-overpressure peaks, which can cause damage to external personnel and equipment. To further reveal the characteristics, the propagation and distribution of blast waves along the axial direction of the explosion venting vessel were investigated. The internal explosion tests with 30 g TNT on the explosion venting vessel were carried out and overpressure sensors were set in front of the vessel opening to record the pressure time history. A quarter numerical model of the explosion venting vessel was established and 50/90 gauges were set along the direction of explosion venting. The effectiveness of the model was illustrated, showing that the error of the impulse of gauge 5 ranges from 5% to 15% at two detonation locations. The propagation of blast waves was analyzed considering the influence of the charge shape and the detonation location. Moreover, the variation of peak overpressure, positive pressure duration, and specific impulse of blast waves from the explosion venting vessel were revealed. The results show that during the explosion venting process, the shape of the wave front can be summarized into three types: straw-hat, jellyfish, and semicircle shape, and the reason for their formation was explained. Compared with the spherical charge, cylindrical charges would affect the shape of the wave front and increase the propagation velocity of blast waves. The charge shape has a significant effect on the peak overpressure, when the scaled distance is less than 1.19 m/kg1/3. As the axial distance from the vessel opening increases, the average impulse decreases at first, then increases, and decreases in the end. It is indicated that using impulse as a parameter can better reflect the characteristic of blast loading acting on the outside.