Abstract: The numerical model of typical industrial plant was established based on the computational fluid dynamics theory.The coupling vented explosion of roof and walls on both sides under natural gas explosion are studied, and the distribution characteristics of indoor explosion overpressure load due to coupling venting are mainly studied. The results show that: Under the coupling of roof and walls on both sides, there are two significant overpressure peaks and multiple oscillatory peaks in the explosion overpressure load in the plant. The first peak overpressure mainly depends on the minimum value of the activation pressure of the entire vent, which is less affected by the coupling vented explosion of roof and walls. The second peak overpressure is more significantly affected by coupling vented explosion of roof and walls on both sides. When the roof is only set with vent, the second peak overpressures are smaller. When the walls on both sides are only set with vents, the second peak overpressures are larger. When both the roof and the walls on both sides are set with vents, the second peak overpressure reach their maximum overpressure away from the ignition source at one end. The roof vent can be more effective to reduce the second peak overpressure within the plant, and the effect of the roof vent area on the peak overpressures and the arrival time is insignificant. The conclusion of the study provides scientific basis for the safety design of the venting explosion facilities of industrial plants, and the investigation and analysis of natural gas explosion.

Key words: natural gas, vented explosion, explosion overpressure, industrial plant