Natural gas explosion characteristics and structural failures in typical residence under different ignition positions

Based on typical residence, a full-scale large space explosion test platform of 280.35 m³ was built, and an equal-scale physical model was established. The explosion characteristics and structural failure of natural gas in residence under different ignition positions were investigated by experiment and simulation. Results indicated the flame venting followed a sequence from the ignition room window to the bathroom window or entrance door and finally to the window of the most adjacent room for different ignition positions. Compared with igniting in the small space, the peak temperature and peak overpressure of the indoor explosion showed an increasing trend when igniting in the large space. The peak flame temperature at ignition in the dining room was the highest, reaching 2492.75 K, which was 3.75 % higher than the lowest peak flame temperature. When igniting in the living room, the time required to reach injure Level IV in the residence was the longest, which was 35.21 % higher than that when igniting in the bathroom. In addition, the explosion intensity (explosion peak overpressure) generated by different ignition positions was as follows: living room and dining room > bedroom > bathroom. Compared with igniting in the dining room, the velocity and mass proportion of glass fragments were higher when igniting in the bathroom, which were 32.06 m/s and 53.12 % respectively. Under the effect of overpressure difference, the masonry wall in the residence opened from the small space to the large space.