Explosion characteristics of nano-PMMA particles

Explosion characteristics of PMMA particles with three different diameters (100 nm, 800 nm, and 30 $\mu$m) are studied experimentally. The explosion severity including the maximum explosion pressure and the pressure rise rate of 100-nm PMMA particles significantly exceed those of 800-nm and 30-$\mu$m PMMA particles at low concentrations due to a greater specific surface area. However, the explosion severity of 100-nm PMMA particles gradually decreases below that of 800-nm PMMA particles once the dust concentration reaches 250 g/m$^3$ and above because 100-nm PMMA particles are prone to agglomerate, but it is still higher than that of 30-$\mu$m PMMA particles. In addition, the maximum explosion pressures increase with increasing concentrations of PMMA particles of all sizes, peaking at 250 g/m$^3$, while they do not change significantly as the concentrations go beyond 500 g/m$^3$. According to the explosion classification based on the deflagration index, nano-PMMA particles indicate a higher explosion risk and more serious explosion severity than those of micro-particles.