Research on the evolution of state field and damage range of multiple source cloud explosions

•The distribution law of cloud explosion field with multipoint explosion is revealed.•A full-size finite element model of multipoint cloud explosion is established.•The multipoint cloud explosion power evaluation based on P-I criterion is realized. Multi-source cloud detonations, as a form of industrial hazard, pose a significantly increased risk. To investigate the distribution of the state field and the extent of damage caused by multi-source cloud detonations, an experimental setup in an open space, along with numerical simulation, was employed to reconstruct the state field. The equivalent area method was utilized to analyze the distribution patterns of the overpressure field, impulse field, and the combined overpressure-impulse field associated with multi-source cloud detonations. The study demonstrates that the numerical simulation method developed aligns with experimental outcomes within a 10 % margin of error, thereby validating the accuracy of the simulation model. As the distance between the multiple explosive sources in a cloud detonation increases, the overpressure field, impulse field, and the combined overpressure-impulse field all exhibit a trend of initially increasing and then decreasing. Notably, the threshold ranges of 0.1 MPa, 0.05 MPa, and 0.03 MPa for multi-point cloud detonations each reach their maximum when the distribution distance of the explosive sources is twice the radius of the threshold range for a single explosive source. The overpressure-impulse criterion is found to be a more rational metric for characterizing the damage extent of multi-point cloud detonations. According to this criterion, the extent of level-five damage under various conditions is approximately located at a position 5.5 times the scale distance.