Numerical study of external explosion characteristics induced by indoor natural gas vented explosion

Purpose - The purpose of this paper is to ascertain the harm to personnel and equipment caused by an external explosion during natural gas explosion venting. The external explosion characteristics induced by the indoor natural gas explosion are the focal points of the investigation. Design/methodology/approach - Computational fluid dynamics technology was used to investigate the large-scale explosion venting process of natural gas in a 6 x 3 x 2.5 m room, and the characteristics of external explosion under different scaled vent size (K-v = A(v)/V2/3, 0.05, 0.08, 0.13, 0.18) were numerically analyzed. Findings - When K-v = 0.08, the length and duration of the explosion fireball are 13.39 and 450 ms, respectively, which significantly expands the degree and range of high-temperature hazards. The suitable flow-field structure causes the external explosion overpressure to be more than twice that indoors, i.e. the natural gas explosion venting overpressure may be considerably more hazardous in an outdoor environment than inside a room. A specific range for the K-v can promote the superposition of outdoor rupture waves and explosion shock waves, thereby creating a new overpressure hazard. Originality/value - Little attention has been devoted to investigating systematically the external explosion hazards. Based on the numerical simulation and the analysis, the external explosion characteristics induced by the indoor large-scale gas explosion were obtained. The research results are theoretically significant for mitigating the effects of external gas explosions on personnel and equipment.