Explosion mechanism of nano-sized dust cloud in interconnected vessels

The effect of pipe diameter and volume ratio on overpressure characteristics and flame propagation behavior of nano-sized PMMA dust in interconnected vessels is investigated in this study. To reveal the explosion mechanism of nano-sized dust clouds in interconnected vessels, a model to predict the pre-compression level of turbulence and choking flow is established. The results show that the dust explosions in interconnected vessels go through three stages: the forward flow of the medium, the violent combustion of the pre-compressed dust cloud, and pressure oscillations. Due to changes in the geometry of the pipe inlet, the flame front is stretched and accelerated propagates. The loss of kinetic energy and the suspended acceleration of the flame front depend heavily on the diameter of the pipe. The increase in volume ratio significantly enhances the explosion intensity in the second vessel. Particularly, for a pipe diameter of 40 mm, the maximum explosion overpressure with a volume ratio of 6 is 2.6 times that of a 1/6 volume ratio, and the maximum pressure rise rate is 10.14 times higher. The prediction model accurately predicts the pre-compression in the second vessel, which supports the safety design of interconnected vessels in industrial processes.