Experimental study of explosion overpressure and flame propagation of micro-sized and nanosized iron powder

In order to study the explosion of micro-sized and nanosized iron powder, the explosion overpressure and flame propagation were measured in a 20-L near-spherical explosion pressure experiment and a Hartmann tube experiment. The explosion overpressure experiments show that the optimum explosion concentrations of micro-sized and nanosized iron powder are 750 and 375 g/m(3), respectively. The maximum explosion pressure and the maximum explosion pressure rise rate of nanosized iron powder are 0.56 MPa and 46.41 MPa/s, which are 144% and 225% of that of micro-sized iron powder, respectively. Under the optimum explosion concentration, the explosion flame of nanosized iron powder is brighter, and the propagation time is shorter. The maximum propagation velocity of micro-sized and nanosized iron powder flame is 0.84 and 6.55 m/s, respectively, and the flame pulsation degree of micro-sized iron powder is larger. The spherical particles and the cracks on the surface of the product particles were observed in the micro images of the explosion products, and the explosion mechanism model of micro-sized and nanosized iron powder was obtained. It was observed that the deformation of micro-sized iron particles intensifies, forming regular and complete spherical iron oxide particles.